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1.
  • Aaltonen, H. Laura, et al. (författare)
  • Airspace dimension assessment with nanoparticles as a proposed biomarker for emphysema
  • 2021
  • Ingår i: Thorax. - : BMJ. - 0040-6376 .- 1468-3296. ; 76:10, s. 1040-1043
  • Tidskriftsartikel (refereegranskat)abstract
    • Airspace dimension assessment with nanoparticles (AiDA) is a novel method to measure distal airspace radius non-invasively. In this study, AiDA radii were measured in 618 individuals from the population-based Swedish CArdiopulmonary BioImaging Study, SCAPIS. Subjects with emphysema detected by computed tomography were compared to non-emphysematous subjects. The 47 individuals with mainly mild-to-moderate visually detected emphysema had significantly larger AiDA radii, compared with non-emphysematous subjects (326±48 μm vs 291±36 μm); OR for emphysema per 10 μm: 1.22 (1.13-1.30, p<0.0001). Emphysema according to CT densitometry was similarly associated with larger radii compared with non-emphysematous CT examinations (316±41 μm vs 291 μm±26 μm); OR per 10 μm: 1.16 (1.08-1.24, p<0.0001). The results are in line with comparable studies. The results show that AiDA is a potential biomarker for emphysema in individuals in the general population.
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2.
  • Alterbeck, Max, et al. (författare)
  • A pilot study of an organised population-based testing programme for prostate cancer
  • 2024
  • Ingår i: BJU International. - 1464-4096. ; 133:1, s. 87-95
  • Tidskriftsartikel (refereegranskat)abstract
    • ObjectiveTo determine the feasibility of a digitally automated population-based programme for organised prostate cancer testing (OPT) in Southern Sweden.Patients and MethodsA pilot project for a regional OPT was conducted between September 2020 and February 2021, inviting 999 randomly selected men aged 50, 56, or 62 years. Risk stratification was based on prostate-specific antigen (PSA) level, PSA density (PSAD), and bi-parametric prostate magnetic resonance imaging (MRI). Men with a PSA level of 3-99 ng/mL had an MRI, and men with elevated PSA level (& GE;3 ng/mL) had a urological check-up, including a digital rectal examination and transrectal ultrasonography (TRUS). Indications for targeted and/or systematic transrectal prostate biopsies were suspicious lesions on MRI (Prostate Imaging-Reporting and Data System [PI-RADS] 4-5) and/or PSAD > 0.15 ng/mL/mL. Additional indications for prostate biopsies were palpable tumours, PSA ratio < 0.1, or cancer suspicion on TRUS. Patient selection, mail correspondence, data collection, and algorithm processing were performed by an automated digital management system. Feasibility is reported descriptively.ResultsA total of 418 men had a PSA test (42%), with increasing participation rates by age (50 years, 38%; 56 years, 44%; and 62 years, 45%). Among these, 35 men (8%) had elevated PSA levels (& GE;3 ng/mL: one of 139, aged 50 years; 10/143, aged 56 years; and 24/146, aged 62 years). On MRI, 16 men (48%) had a negative scan (PI-RADS < 3), seven men (21%) had PI-RADS 3, nine men (27%) had PI-RADS 4, and one man (3%) had PI-RADS 5. All men with PI-RADS 4 or 5 underwent prostate biopsies, as well as two men with PI-RADS 3 due to PSAD > 0.15 ng/mL/mL or a suspicious finding on TRUS. Prostate cancer was diagnosed in 10 men. Six men underwent active treatment, whereas four men were assigned to active surveillance.ConclusionOur OPT model is feasible from an operational point of view, but due to the limited scale of this study no conclusions can be made regarding the efficacy of the diagnostic model or outcome.
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3.
  • Andersson, Ingvar, et al. (författare)
  • Breast tomosynthesis and digital mammography: a comparison of breast cancer visibility and BIRADS classification in a population of cancers with subtle mammographic findings.
  • 2008
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 18, s. 2817-2825
  • Tidskriftsartikel (refereegranskat)abstract
    • The main purpose was to compare breast cancer visibility in one-view breast tomosynthesis (BT) to cancer visibility in one- or two-view digital mammography (DM). Thirty-six patients were selected on the basis of subtle signs of breast cancer on DM. One-view BT was performed with the same compression angle as the DM image in which the finding was least/not visible. On BT, 25 projections images were acquired over an angular range of 50 degrees, with double the dose of one-view DM. Two expert breast imagers classified one- and two-view DM, and BT findings for cancer visibility and BIRADS cancer probability in a non-blinded consensus study. Forty breast cancers were found in 37 breasts. The cancers were rated more visible on BT compared to one-view and two-view DM in 22 and 11 cases, respectively, (p < 0.01 for both comparisons). Comparing one-view DM to one-view BT, 21 patients were upgraded on BIRADS classification (p < 0.01). Comparing two-view DM to one-view BT, 12 patients were upgraded on BIRADS classification (p < 0.01). The results indicate that the cancer visibility on BT is superior to DM, which suggests that BT may have a higher sensitivity for breast cancer detection.
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4.
  • Axelsson, Rebecca, et al. (författare)
  • Computer model of mechanical imaging acquisition for virtual clinical trials
  • 2021
  • Ingår i: Medical Imaging 2021 : Physics of Medical Imaging - Physics of Medical Imaging. - : SPIE. - 1605-7422. - 9781510640191 ; 11595, s. 1-115950
  • Konferensbidrag (refereegranskat)abstract
    • Malignant breast tumours can be distinguished from benign lesions and normal tissue based on their mechanical properties. Our pilot studies have demonstrated the potential of using Mechanical Imaging (MI) combined with mammography to reduce recalls and false positives in breast cancer screening by more accurately identifying benign lesions. To enable further optimization of MI we propose a computer simulation of the MI acquisition, for use in a Virtual Clinical Trial (VCT) framework. VCTs are computer simulated clinical trials used to efficiently evaluate clinical imaging systems. A linear elastic finite element (FE) model of the breast under dynamic compression was implemented using an open-source FE solver. A spherical tumour (15 mm in diameter) was inserted into the simulated predominantly adipose breast. The location and stiffness of the tumour was varied. The average stress on the compressed breast surface was calculated and compared with the local average stress at the tumour location and the Relative Mean Pressure over lesion Area (RMPA) was calculated. Preliminary results were within a realistic range with an average stress on the breast (tumour) of 5.9-16.6 kPa which is in agreement with published values between 1.0 - 22.5 kPa. This corresponds to RMPA values of 0.96-2.15 depending on stiffness and location of the tumour. This can lead to more detailed validation of various MI acquisition schemes through VCTs before their use in clinical studies.
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5.
  • Axelsson, Rebecca, et al. (författare)
  • Finite element model of mechanical imaging of the breast
  • 2022
  • Ingår i: Journal of Medical Imaging. - 2329-4302. ; 9:3, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Malignant breast lesions can be distinguished from benign lesions by their mechanical properties. This has been utilized for mechanical imaging in which the stress distribution over the breast is measured. Mechanical imaging has shown the ability to identify benign or normal cases and to reduce the number of false positives from mammography screening. Our aim was to develop a model of mechanical imaging acquisition for simulation purposes. To that end, we simulated mammographic compression of a computer model of breast anatomy and lesions. Approach: The breast compression was modeled using the finite element method. Two finite element breast models of different sizes were used and solved using linear elastic material properties in open-source virtual clinical trial (VCT) software. A spherical lesion (15 mm in diameter) was inserted into the breasts, and both the location and stiffness of the lesion were varied extensively. The average stress over the breast and the average stress at the lesion location, as well as the relative mean pressure over lesion area (RMPA), were calculated. Results: The average stress varied 6.2-6.5 kPa over the breast surface and 7.8-11.4 kPa over the lesion, for different lesion locations and stiffnesses. These stresses correspond to an RMPA of 0.80 to 1.46. The average stress was 20% to 50% higher at the lesion location compared with the average stress over the entire breast surface. Conclusions: The average stress over the breast and the lesion location corresponded well to clinical measurements. The proposed model can be used in VCTs for evaluation and optimization of mechanical imaging screening strategies.
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6.
  • Axelsson, Rebecca, et al. (författare)
  • Simultaneous digital breast tomosynthesis and mechanical imaging in women recalled from screening - A preliminary analysis
  • 2022
  • Ingår i: 16th International Workshop on Breast Imaging, IWBI 2022. - : SPIE. - 0277-786X .- 1996-756X. - 9781510655843 ; 12286
  • Konferensbidrag (refereegranskat)abstract
    • We have developed a method for simultaneous tomosynthesis and mechanical imaging, called DBTMI. Mechanical imaging measures the stress distribution over the compressed breast surface. Malignant tissue is usually stiffer than benign, which results in higher stress on the compressed breast and enables to distinguish malignant from benign findings. By combining tomosynthesis and mechanical imaging, we could improve cancer detection accuracy by reducing the number of false positive findings. In this study we have analysed clinical DBTMI data, collected from 52 women from an ongoing pilot study at the Skåne University Hospital, Malmö, Sweden. We measured the range of the average stress over the breast surface, the range of average stress over the location of suspected lesions, and the normalized stress over the lesion location. Preliminary results show that the range of stress over the breast surface was 1.23-5.84 kPa, the range over the lesion location 2.10-10.10 kPa, and the normalized stress 1.12-2.44 over the lesion location. Overall, the local stress over malignant lesions was higher than the average stress over the entire breast surface. This is the first step investigating criteria to distinguish between malignant and benign findings based upon clinical DBTMI data.
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7.
  • Bakic, Predrag R., et al. (författare)
  • Artifact reduction in simultaneous tomosynthesis and mechanical imaging of the breast
  • 2019
  • Ingår i: Medical Imaging 2019 : Physics of Medical Imaging - Physics of Medical Imaging. - : SPIE. - 9781510625433 ; 10948
  • Konferensbidrag (refereegranskat)abstract
    • Mechanical imaging (MI) uses a pressure sensor array to estimate the stiffness of lesions. Recent clinical studies have suggested that MI combined with digital mammography may reduce false positive findings and negative biopsies by over 30%. Digital breast tomosynthesis (DBT) has been adopted progressively in cancer screening. The tomographic nature of DBT improves lesion visibility by reducing tissue overlap in reconstructed images. For maximum benefit, DBT and MI data should be acquired simultaneously; however, that arrangement produces visible artifacts in DBT images due to the presence of the MI sensor array. We propose a method for reducing artifacts during the DBT image reconstruction. We modified the parameters of a commercial DBT reconstruction engine and investigated the conspicuity of artifacts in the resultant images produced with different sensor orientations. The method was evaluated using a physical anthropomorphic phantom imaged on top of the sensor. Visual assessment showed a reduction of artifacts. In a quantitative test, we calculated the artifact spread function (ASF), and compared the ratio of the mean ASF values between the proposed and conventional reconstruction (termed ASF ratio, RASF). We obtained a mean RASF of 2.74, averaged between two analyzed sensor orientations (45° and 90°). The performance varied with the orientation and the type of sensor structures causing the artifacts. RASF for wide connection lines was larger at 45° than at 90° (5.15 vs. 1.00, respectively), while for metallic contacts RASF was larger at 90° than at 45° (3.31 vs. 2.21, respectively). Future work will include a detailed quantitative assessment, and further method optimization in virtual clinical trials.
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8.
  • Bakic, Predrag R., et al. (författare)
  • Evaluation of a flat fielding method for simultaneous DBT and MI acquisition
  • 2020
  • Ingår i: 15th International Workshop on Breast Imaging, IWBI 2020. - : SPIE. - 1996-756X .- 0277-786X. - 9781510638310 ; 11513
  • Konferensbidrag (refereegranskat)abstract
    • We are developing a prototype system for simultaneous digital breast tomosynthesis (DBT) and mechanical imaging (MI). MI maps the local pressure distribution during clinical exams, to distinguish breast abnormalities from the normal tissue. Both DBT alone, and MI when combined with digital mammography, have demonstrated the ability to reduce false positives; however, the benefit of combining DBT with MI has not been investigated. A practical limitation in simultaneous DBT and MI is the presence of the MI sensor in DBT images. Metallic elements of the sensor generate noticeable artifacts, which may interfere with clinical analysis. Previously, we shown that the sensor artifacts can be reduced by flat fielding, which combines projections of the sensor acquired with and without the breast. In this paper we evaluate the flat fielding by assessing artifact reduction and visibility of breast abnormalities. Images of a physical anthropomorphic breast phantom were acquired using a clinical wide-angle DBT system. Visual evaluation was performed by experienced medical physicists. Image quality descriptors were calculated in images with and without flat fielding. To evaluate the visibility of abnormalities we estimated the full width at half maximum (FWHM) for calcifications modeled in the phantom. Our preliminary results suggest a substantial reduction of artifacts by flat fielding (on average 83%). Few noticeable artifacts remain near the breast edge, in the reconstructed image with the sensor in focus. We observed a 17% reduction in the FWHM. Future work would include a detailed assessment, and method optimization using virtual trials as a design aid.
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9.
  • Bakic, Predrag R., et al. (författare)
  • Pre-processing for image quality improvement in simultaneous DBT and mechanical imaging
  • 2020
  • Ingår i: Medical Imaging 2020 : Physics of Medical Imaging - Physics of Medical Imaging. - : SPIE. - 1605-7422. - 9781510633919 ; 11312
  • Konferensbidrag (refereegranskat)abstract
    • Simultaneous digital breast tomosynthesis (DBT) and mechanical imaging (MI) offer the potential to combine anatomic information from DBT with functional information from MI. This makes it possible to associate tissue stiffness with specific anatomic structures in the breast, a combination that can reduce false-positive findings by using the MI data to discriminate between ambiguous lesions in DBT. This, in turn, will reduce the frequency of negative biopsies. Simultaneous imaging requires that the MI sensor array be present during DBT acquisition. This introduces artifacts, since the sensor is attenuating. Previously, we demonstrated that the DBT reconstruction could be modified to reduce sensor conspicuity in DBT images. In this paper, we characterize the relative attenuation of the breast and the sensor, to calculate the artifact reduction in DBT reconstruction. We concentrate on pre-processing DBT projections prior to reconstruction. Using commercially available a DBT system, we have confirmed that the sensor array does not completely attenuate the x-rays. This suggests that a pre-processing method based upon flat fielding can be used to reduce artifacts. In a proof-of-concept study, we performed flat fielding by combining DBT projections of the MI sensor with and without an anthropomorphic breast phantom. Visual evaluation confirmed substantially improved image quality. The artifacts were reduced throughout the image for all sensor elements. Few residual artifacts are noticeable where the phantom thickness decreases. The investigation of additional pre-processing, including beam hardening correction is ongoing. Future work includes quantitative validation, noise stabilization, and method optimization in virtual clinical trials and subsequent patient studies.
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10.
  • Barufaldi, Bruno, et al. (författare)
  • Virtual Clinical Trials in Medical Imaging System Evaluation and Optimisation
  • 2021
  • Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 195:3-4, s. 363-371
  • Tidskriftsartikel (refereegranskat)abstract
    • Virtual clinical trials (VCTs) can be used to evaluate and optimise medical imaging systems. VCTs are based on computer simulations of human anatomy, imaging modalities and image interpretation. OpenVCT is an open-source framework for conducting VCTs of medical imaging, with a particular focus on breast imaging. The aim of this paper was to evaluate the OpenVCT framework in two tasks involving digital breast tomosynthesis (DBT). First, VCTs were used to perform a detailed comparison of virtual and clinical reading studies for the detection of lesions in digital mammography and DBT. Then, the framework was expanded to include mechanical imaging (MI) and was used to optimise the novel combination of simultaneous DBT and MI. The first experiments showed close agreement between the clinical and the virtual study, confirming that VCTs can predict changes in performance of DBT accurately. Work in simultaneous DBT and MI system has demonstrated that the system can be optimised in terms of the DBT image quality. We are currently working to expand the OpenVCT software to simulate MI acquisition more accurately and to include models of tumour growth. Based on our experience to date, we envision a future in which VCTs have an important role in medical imaging, including support for more imaging modalities, use with rare diseases and a role in training and testing artificial intelligence (AI) systems.
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11.
  • Bejnö, Anna, et al. (författare)
  • Artificial intelligence together with mechanical imaging in mammography
  • 2020
  • Ingår i: 15th International Workshop on Breast Imaging, IWBI 2020. - : SPIE. - 0277-786X .- 1996-756X. - 9781510638310 ; 11513
  • Konferensbidrag (refereegranskat)abstract
    • Artificial intelligence (AI) applications are increasingly seeing use in breast imaging, particularly to assist in or automate the reading of mammograms. Another novel technique is mechanical imaging (MI) which estimates the relative stiffness of suspicious breast abnormalities by measuring the distribution of pressure on the compressed breast. This study investigates the feasibility of combining AI and MI information in breast imaging to provide further diagnostic information. Forty-six women recalled from screening were included in the analysis. Mammograms with findings scored on a suspiciousness scale by an AI tool, and corresponding pressure distributions were collected for each woman. The cases were divided into three groups by diagnosis; biopsy-proven cancer, biopsy-proven benign and non-biopsied, very likely benign. For all three groups, the relative increase of pressure at the location of the finding marked most suspicious by the AI software was recorded. A significant correlation between the relative pressure increase at the AI finding and the AI score was established in the group with cancer (p=0.043), but neither group of healthy women showed such a correlation. This study suggests that AI and MI indicate independent markers for breast cancer. The combination of these two methods has the potential to increase the accuracy of mammography screening, but further research is needed.
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12.
  • Bengtsson, Johan, et al. (författare)
  • Correlation between ADC, ADC ratio, and Gleason Grade group in prostate cancer patients undergoing radical prostatectomy : Retrospective multicenter study with different MRI scanners
  • 2023
  • Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: MRI is an important tool in the prostate cancer work-up, with special emphasis on the ADC sequence. This study aimed to investigate the correlation between ADC and ADC ratio compared to tumor aggressiveness determined by a histopathological examination after radical prostatectomy.Methods: Ninety-eight patients with prostate cancer underwent MRI at five different hospitals prior to radical prostatectomy. Images were retrospectively analyzed individually by two radiologists. The ADC of the index lesion and reference tissues (contralateral normal prostatic, normal peripheral zone, and urine) was recorded. Absolute ADC and different ADC ratios were compared to tumor aggressivity according to the ISUP Gleason Grade Groups extracted from the pathology report using Spearman’s rank correlation coefficient (ρ). ROC curves were used to evaluate the ability to discriminate between ISUP 1-2 and ISUP 3-5 and intra class correlation and Bland-Altman plots for interrater reliability.Results: All patients had prostate cancer classified as ISUP grade ≥ 2. No correlation was found between ADC and ISUP grade. We found no benefit of using the ADC ratio over absolute ADC. The AUC for all metrics was close to 0.5, and no threshold could be extracted for prediction of tumor aggressivity. The interrater reliability was substantial to almost perfect for all variables analyzed.Conclusions: ADC and ADC ratio did not correlate with tumor aggressiveness defined by ISUP grade in this multicenter MRI study. The result of this study is opposite to previous research in the field.
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13.
  • Bick, Ulrich, et al. (författare)
  • Image-guided breast biopsy and localisation : recommendations for information to women and referring physicians by the European Society of Breast Imaging
  • 2020
  • Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We summarise here the information to be provided to women and referring physicians about percutaneous breast biopsy and lesion localisation under imaging guidance. After explaining why a preoperative diagnosis with a percutaneous biopsy is preferred to surgical biopsy, we illustrate the criteria used by radiologists for choosing the most appropriate combination of device type for sampling and imaging technique for guidance. Then, we describe the commonly used devices, from fine-needle sampling to tissue biopsy with larger needles, namely core needle biopsy and vacuum-assisted biopsy, and how mammography, digital breast tomosynthesis, ultrasound, or magnetic resonance imaging work for targeting the lesion for sampling or localisation. The differences among the techniques available for localisation (carbon marking, metallic wire, radiotracer injection, radioactive seed, and magnetic seed localisation) are illustrated. Type and rate of possible complications are described and the issue of concomitant antiplatelet or anticoagulant therapy is also addressed. The importance of pathological-radiological correlation is highlighted: when evaluating the results of any needle sampling, the radiologist must check the concordance between the cytology/pathology report of the sample and the radiological appearance of the biopsied lesion. We recommend that special attention is paid to a proper and tactful approach when communicating to the woman the need for tissue sampling as well as the possibility of cancer diagnosis, repeat tissue sampling, and or even surgery when tissue sampling shows a lesion with uncertain malignant potential (also referred to as “high-risk” or B3 lesions). Finally, seven frequently asked questions are answered.
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14.
  • Bjerkén, Anna, et al. (författare)
  • Dose evaluation of simultaneous breast radiography and mechanical imaging
  • 2023
  • Ingår i: Medical Imaging 2023 : Physics of Medical Imaging - Physics of Medical Imaging. ; 12463
  • Konferensbidrag (refereegranskat)abstract
    • This study investigates the impact in terms of radiation dose when performing simultaneous digital breast tomosynthesis(DBT) and mechanical imaging (MI) – DBTMI. DBTMI has demonstrated the potential to increase specificity of cancerdetection, and reduce unnecessary biopsies, as compared to digital mammography (DM) screening. The presence of theMI sensor during simultaneous image acquisition may increase the radiation dose when automatic exposure control is used.In this project, a radiation dose study was conducted on clinically available breast imaging systems with and without theMI sensor. We have investigated three approaches to analyse the dose increase in DBTMI, using (i) the estimates of averageglandular dose (AGD) reported in DICOM headers of radiography images; (ii) AGD measured by a conventionaldosemeter; and (iii) AGD measured by optically stimulated luminescence using NaCl pellets. The relative increase in AGDestimated from DICOM headers when using the MI sensor was on average 10.7% and 12.4%, for DM and DBTmeasurements, respectively. The relative increase in AGD using the conventional dosemeter was 11.2% in DM mode and12.2% in DBT mode. The relative increase in AGD using NaCl pellets was 14.6% in DM mode. Our measurements suggestthat the use of simultaneous breast radiography and MI increases the AGD by 13% on average. The increase in dose is stillbelow the acceptable values in mammography screening recommended by the European Guidelines.
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15.
  • Bjöersdorff, Mimmi, et al. (författare)
  • Detection of lymph node metastases in patients with prostate cancer: Comparing conventional and digital F-18 -fluorocholine PET-CT using histopathology as a reference
  • 2022
  • Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X.
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Positron emission tomography-computed tomography (PET-CD with [F-18]-fluorocholine (FCH) is used to detect and stage metastatic lymph nodes in patients with prostate cancer. Improvements to hardware and software have recently been made. We compared the capability of detecting regional lymph node metastases using conventional and digital silicon photomultiplier (SiPM)-based PET-CT technology for FCH. Extended pelvic lymph node dissection (ePLND) histopathology was used as a reference method. Methods: The study retrospectively examined 177 patients with intermediate or high-risk prostate cancer who had undergone staging with FCH PET-CT before ePLND. Images were obtained with either the conventional Philips Gemini PET-CT (n = 93) or the digital SiPM-based GE Discovery MI PET-CT (n = 84) and compared. Results: Images that were obtained using the Philips Gemini PET-CT system showed 19 patients (20%) with suspected lymph node metastases, whereas the GE Discovery MI PET-CT revealed 36 such patients (43%). The sensitivity, specificity, and positive and negative predictive values were 0.3, 0.84, 0.47, and 0.72 for the Philips Gemini, while they were 0.58, 0.62, 0.31, and 0.83 for the GE Discovery MI, respectively. The areas under the curves in a receiver operating characteristic curve analysis were similar between the two PET-CT systems (0.57 for Philips Gemini and 0.58 for GE Discovery MI, p = 0.89). Conclusions: Marked differences in sensitivity and specificity were found for the different PET-CT systems, although the overall diagnostic performance was similar. These differences are probably due to differences in both hardware and software, including reconstruction algorithms, and should be considered when new technology is introduced.
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16.
  • Bjöersdorff, Mimmi, et al. (författare)
  • Impact of penalizing factor in a block-sequential regularized expectation maximization reconstruction algorithm for 18 F-fluorocholine PET-CT regarding image quality and interpretation
  • 2019
  • Ingår i: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 6:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Recently, the block-sequential regularized expectation maximization (BSREM) reconstruction algorithm was commercially introduced (Q.Clear, GE Healthcare, Milwaukee, WI, USA). However, the combination of noise-penalizing factor (β), acquisition time, and administered activity for optimal image quality has not been established for 18 F-fluorocholine (FCH). The aim was to compare image quality and diagnostic performance of different reconstruction protocols for patients with prostate cancer being examined with 18 F-FCH on a silicon photomultiplier-based PET-CT. Thirteen patients were included, injected with 4 MBq/kg, and images were acquired after 1 h. Images were reconstructed with frame durations of 1.0, 1.5, and 2.0 min using β of 150, 200, 300, 400, 500, and 550. An ordered subset expectation maximization (OSEM) reconstruction with a frame duration of 2.0 min was used for comparison. Images were quantitatively analyzed regarding standardized uptake values (SUV) in metastatic lymph nodes, local background, and muscle to obtain contrast-to-noise ratios (CNR) as well as the noise level in muscle. Images were analyzed regarding image quality and number of metastatic lymph nodes by two nuclear medicine physicians. Results: The highest median CNR was found for BSREM with a β of 300 and a frame duration of 2.0 min. The OSEM reconstruction had the lowest median CNR. Both the noise level and lesion SUV max decreased with increasing β. For a frame duration of 1.5 min, the median quality score was highest for β 400-500, and for a frame duration of 2.0 min the score was highest for β 300-500. There was no statistically significant difference in the number of suspected lymph node metastases between the different image series for one of the physicians, and for the other physician the number of lymph nodes differed only for one combination of image series. Conclusions: To achieve acceptable image quality at 4 MBq/kg 18 F-FCH, we propose using a β of 400-550 with a frame duration of 1.5 min. The lower β should be used if a high CNR is desired and the higher if a low noise level is important.
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17.
  • Boita, Joana, et al. (författare)
  • Development and content validity evaluation of a candidate instrument to assess image quality in digital mammography : A mixed-method study
  • 2021
  • Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X. ; 134
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To develop a candidate instrument to assess image quality in digital mammography, by identifying clinically relevant features in images that are affected by lower image quality. Methods: Interviews with fifteen expert breast radiologists from five countries were conducted and analysed by using adapted directed content analysis. During these interviews, 45 mammographic cases, containing 44 lesions (30 cancers, 14 benign findings), and 5 normal cases, were shown with varying image quality. The interviews were performed to identify the structures from breast tissue and lesions relevant for image interpretation, and to investigate how image quality affected the visibility of those structures. The interview findings were used to develop tentative items, which were evaluated in terms of wording, understandability, and ambiguity with expert breast radiologists. The relevance of the tentative items was evaluated using the content validity index (CVI) and modified kappa index (k*). Results: Twelve content areas, representing the content of image quality in digital mammography, emerged from the interviews and were converted into 29 tentative items. Fourteen of these items demonstrated excellent CVI ≥ 0.78 (k* > 0.74), one showed good CVI < 0.78 (0.60 ≤ k* ≤ 0.74), while fourteen were of fair or poor CVI < 0.78 (k* ≤ 0.59). In total, nine items were deleted and five were revised or combined resulting in 18 items. Conclusions: By following a mixed-method methodology, a candidate instrument was developed that may be used to characterise the clinically-relevant impact that image quality variations can have on digital mammography.
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18.
  • Boita, Joana, et al. (författare)
  • How does image quality affect radiologists’ perceived ability for image interpretation and lesion detection in digital mammography?
  • 2021
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 31:7, s. 5335-5343
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: To study how radiologists’ perceived ability to interpret digital mammography (DM) images is affected by decreases in image quality. Methods: One view from 45 DM cases (including 30 cancers) was degraded to six levels each of two acquisition-related issues (lower spatial resolution and increased quantum noise) and three post-processing-related issues (lower and higher contrast and increased correlated noise) seen during clinical evaluation of DM systems. The images were shown to fifteen breast screening radiologists from five countries. Aware of lesion location, the radiologists selected the most-degraded mammogram (indexed from 1 (reference) to 7 (most degraded)) they still felt was acceptable for interpretation. The median selected index, per degradation type, was calculated separately for calcification and soft tissue (including normal) cases. Using the two-sided, non-parametric Mann-Whitney test, the median indices for each case and degradation type were compared. Results: Radiologists were not tolerant to increases (medians: 1.5 (calcifications) and 2 (soft tissue)) or decreases (median: 2, for both types) in contrast, but were more tolerant to correlated noise (median: 3, for both types). Increases in quantum noise were tolerated more for calcifications than for soft tissue cases (medians: 3 vs. 4, p = 0.02). Spatial resolution losses were considered less acceptable for calcification detection than for soft tissue cases (medians: 3.5 vs. 5, p = 0.001). Conclusions: Perceived ability of radiologists for image interpretation in DM was affected not only by image acquisition-related issues but also by image post-processing issues, and some of those issues affected calcification cases more than soft tissue cases. Key Points: • Lower spatial resolution and increased quantum noise affected the radiologists’ perceived ability to interpret calcification cases more than soft tissue lesion or normal cases. • Post-acquisition image processing-related effects, not only image acquisition-related effects, also impact the perceived ability of radiologists to interpret images and detect lesions. • In addition to current practices, post-acquisition image processing-related effects need to also be considered during the testing and evaluation of digital mammography systems.
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19.
  • Boita, Joana, et al. (författare)
  • Validation of a candidate instrument to assess image quality in digital mammography using ROC analysis
  • 2021
  • Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 139
  • Tidskriftsartikel (refereegranskat)abstract
    • PurposeTo validate a candidate instrument, to be used by different professionals to assess image quality in digital mammography (DM), against detection performance results.MethodsA receiver operating characteristics (ROC) study was conducted to assess the detection performance in DM images with four different image quality levels due to different quality issues. Fourteen expert breast radiologists from five countries assessed a set of 80 DM cases, containing 60 lesions (40 cancers, 20 benign findings) and 20 normal cases. A visual grading analysis (VGA) study using a previously-described candidate instrument was conducted to evaluate a subset of 25 of the images used in the ROC study. Eight radiologists that had participated in the ROC study, and seven expert breast-imaging physicists, evaluated this subset. The VGA score (VGAS) and the ROC and visual grading characteristics (VGC) areas under the curve (AUCROC and AUCVGC) were compared.ResultsNo large differences in image quality among the four levels were detected by either ROC or VGA studies. However, the ranking of the four levels was consistent: level 1 (partial AUCROC: 0.070, VGAS: 6.77) performed better than levels 2 (0.066, 6.15), 3 (0.061, 5.82), and 4 (0.062, 5.37). Similarity between radiologists’ and physicists’ assessments was found (average VGAS difference of 10 %).ConclusionsThe results from the candidate instrument were found to correlate with those from ROC analysis, when used by either observer group. Therefore, it may be used by different professionals, such as radiologists, radiographers, and physicists, to assess clinically-relevant image quality variations in DM.
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20.
  • Bolejko, Anetta, et al. (författare)
  • A roller coaster of emotions and sense : coping with the perceived psychosocial consequences of a false-positive screening mammography
  • 2014
  • Ingår i: Journal of Clinical Nursing. - : John Wiley & Sons. - 0962-1067 .- 1365-2702. ; 23:13-13, s. 2053-2062
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims and objectives To explore coping with the perceived psychosocial consequences of a false-positive screening mammography. Background Mammographic screening has been found effective to decrease breast cancer (BC) mortality, yet there are adverse effects. Psychosocial consequences of false-positive mammographic screening have mainly been investigated from a population-based perspective. A call for qualitative studies to further explore these consequences has thus been postulated. To date, qualitative studies have elucidated women's experiences following their recall breast examinations, but their coping with perceived psychosocial consequences of a false-positive screening mammography has not yet been explored. Design An explorative qualitative study. Methods Face-to-face interviews were held with a purposive heterogeneous sample of 13 Swedish-speaking women with a false-positive screening mammography. The transcripts were analysed by the use of an inductive content analysis. Results Coping with the perceived psychosocial consequences of a false-positive screening mammography implied a roller coaster of emotion and sense. Women described how they imagined the worst and were in a state of uncertainty feeling threatened by a fatal disease. Conversely, they felt protected, surrounded by their families and being professionally taken care of, which together with perceived sisterhood and self-empowerment evoked strength and hope. Being aware of family responsibility became a crucial matter. Experiencing false-positive screening raised thoughts of thankfulness and reappraisal of life, although an ounce of BC anxiety remained. Consequently, gained awareness about BC screening and values in life surfaced. Conclusions Experiencing a false-positive screening mammography triggers agonising experiences evoking a variety of coping strategies. Provision of screening raises the issue of responsibility for an impact on psychosocial well-being among healthy women. Relevance to clinical practice Gained knowledge might provide a basis for interventions to prevent psychosocial consequences of false-positive mammographic screening and provide support for women with a potentially compromised ability to overcome such consequences.
  •  
21.
  • Bolejko, Anetta, et al. (författare)
  • A roller coaster of emotions and sense : coping with the perceived psychosocial consequences of a false-positive screening mammography
  • 2014
  • Ingår i: Journal of Clinical Nursing. - : John Wiley & Sons. - 0962-1067 .- 1365-2702. ; 23:13-14, s. 2053-2062
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims and objectives To explore coping with the perceived psychosocial consequences of a false-positive screening mammography. Background Mammographic screening has been found effective to decrease breast cancer (BC) mortality, yet there are adverse effects. Psychosocial consequences of false-positive mammographic screening have mainly been investigated from a population-based perspective. A call for qualitative studies to further explore these consequences has thus been postulated. To date, qualitative studies have elucidated women's experiences following their recall breast examinations, but their coping with perceived psychosocial consequences of a false-positive screening mammography has not yet been explored. Design An explorative qualitative study. Methods Face-to-face interviews were held with a purposive heterogeneous sample of 13 Swedish-speaking women with a false-positive screening mammography. The transcripts were analysed by the use of an inductive content analysis. Results Coping with the perceived psychosocial consequences of a false-positive screening mammography implied a roller coaster of emotion and sense. Women described how they imagined the worst and were in a state of uncertainty feeling threatened by a fatal disease. Conversely, they felt protected, surrounded by their families and being professionally taken care of, which together with perceived sisterhood and self-empowerment evoked strength and hope. Being aware of family responsibility became a crucial matter. Experiencing false-positive screening raised thoughts of thankfulness and reappraisal of life, although an ounce of BC anxiety remained. Consequently, gained awareness about BC screening and values in life surfaced. Conclusions Experiencing a false-positive screening mammography triggers agonising experiences evoking a variety of coping strategies. Provision of screening raises the issue of responsibility for an impact on psychosocial well-being among healthy women.
  •  
22.
  • Bolejko, Anetta, et al. (författare)
  • Adaptation to Swedish and further development of the ‘Consequences of Screening – Breast Cancer’ questionnaire : a multimethod study
  • 2013
  • Ingår i: Scandinavian Journal of Caring Sciences. - : Springer. - 0283-9318 .- 1471-6712. ; 27:2, s. 475-486
  • Tidskriftsartikel (refereegranskat)abstract
    • Rationale:  Experiencing a false-positive screening mammography can cause considerable psychosocial distress. The Consequences of Screening – Breast Cancer questionnaire (COS-BC parts 1 and 2), recently developed in Denmark, is the only condition-specific questionnaire for measuring short- and long-term psychosocial consequences of false-positive mammographic screening. Additional studies are needed to further test the COS-BC before use across cultures. Furthermore, studies have suggested that the consequences of false-positive screening results are partly common across cancer screening settings, although this hypothesis remains largely untested.Objectives:  This study (i) assesses content validity of a Swedish version of the COS-BC, (ii) tests whether items expressing long-term consequences of false-positive lung cancer screening results are relevant in a breast cancer screening context and (iii) explores the usefulness of taking results from Rasch analyses of the source version as an aid in questionnaire translation and adaptation.Methods:  Following dual-panel translation, content validity was assessed through qualitative interviews with representatives of the target population and the content validity index (CVI). Item locations and Rasch model fit of the source questionnaires were considered in the translation and assessment process.Results:  The COS-BC items were generally found relevant and provided coverage of the target construct. Content validity was supported also for nine of 10 lung cancer screening items. Scale CVI values were ≥0.81. Previous Rasch data were useful in facilitating translation and assessing item content validity. The resulting Swedish version of the COS-BC parts 1 and 2 consists of 34 and 23 items, respectively.Conclusion:  This study illustrates the value of methodological triangulation and use of data from previous Rasch analyses in questionnaire translation and adaptation. We found support for the hypothesis that consequences of false-positive screening are common across cancer screening settings. Psychometric properties of the Swedish COS-BC remain to be established.
  •  
23.
  • Bolejko, Anetta, et al. (författare)
  • Adaptation to Swedish and further development of the 'Consequences of Screening - Breast Cancer' questionnaire : a multimethod study
  • 2013
  • Ingår i: Scandinavian Journal of Caring Sciences. - : Springer. - 0283-9318 .- 1471-6712. ; 27:2, s. 475-486
  • Tidskriftsartikel (refereegranskat)abstract
    • Experiencing a false-positive screening mammography can cause considerable psychosocial distress. The Consequences of Screening - Breast Cancer questionnaire (COS-BC parts 1 and 2), recently developed in Denmark, is the only condition-specific questionnaire for measuring short- and long-term psychosocial consequences of false-positive mammographic screening. Additional studies are needed to further test the COS-BC before use across cultures. Furthermore, studies have suggested that the consequences of false-positive screening results are partly common across cancer screening settings, although this hypothesis remains largely untested. This study (i) assesses content validity of a Swedish version of the COS-BC, (ii) tests whether items expressing long-term consequences of false-positive lung cancer screening results are relevant in a breast cancer screening context and (iii) explores the usefulness of taking results from Rasch analyses of the source version as an aid in questionnaire translation and adaptation.Following dual-panel translation, content validity was assessed through qualitative interviews with representatives of the target population and the content validity index (CVI). Item locations and Rasch model fit of the source questionnaires were considered in the translation and assessment process.The COS-BC items were generally found relevant and provided coverage of the target construct. Content validity was supported also for nine of 10 lung cancer screening items. Scale CVI values were ≥0.81. Previous Rasch data were useful in facilitating translation and assessing item content validity. The resulting Swedish version of the COS-BC parts 1 and 2 consists of 34 and 23 items, respectively. This study illustrates the value of methodological triangulation and use of data from previous Rasch analyses in questionnaire translation and adaptation. We found support for the hypothesis that consequences of false-positive screening are common across cancer screening settings. Psychometric properties of the Swedish COS-BC remain to be established.
  •  
24.
  • Bolejko, Anetta, et al. (författare)
  • Prevalence, Long-term Development, and Predictors of Psychosocial Consequences of False-Positive Mammography among Women Attending Population-Based Screening
  • 2015
  • Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 24:9, s. 1388-1397
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Cancer screening aims to detect cancer at an asymptomatic stage, although side effects from screening also occur. We investigated the prevalence, longitudinal development, and predictors of psychosocial consequences of false-positive breast cancer screening. METHODS: Three hundred ninety-nine women with false-positive screening mammography responded to the Consequences of Screening-Breast Cancer (COS-BC) questionnaire immediately after a negative diagnosis (free from breast cancer) following recall examination(s) (baseline), and 6 and 12 months later. Age-matched controls (n = 499) with a negative mammogram responded to the COS-BC at the same occasions. Five COS-BC scales (Sense of dejection, Anxiety, Behavioral, Sleep, and Existential values) were used as outcome measures. RESULTS: Women with false-positive mammography had consistently higher prevalence of all five consequences compared with controls (P < 0.001). The prevalences decreased between baseline and 6 months (P < 0.001) but were stable between 6 and 12 months (P ≥ 0.136). Early recall profoundly predicted long-term consequences for all five outcomes (OR, 3.05-10.31), along with dissatisfaction with information at recall (OR, 2.28-2.56), being foreign-born (OR, 2.35-3.71), and lack of social support (OR, 1.13-1.25). CONCLUSION: This 1-year longitudinal study shows that women experience psychosocial consequences of false-positive screening mammography. Early recall should be performed cautiously, and provision of information as well as social support may reduce psychosocial consequences. IMPACT: Although delivery of population-based screening reduces breast cancer mortality, it also raises the issue of its impact on the psychosocial well-being of healthy women. Our findings identify predictors that can be targeted in future efforts to reduce the side effects of mammographic screening.
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25.
  • Bolejko, Anetta, et al. (författare)
  • Psychometric properties of a Swedish version of the Consequences of Screening : Breast Cancer questionnaire
  • 2014
  • Ingår i: Journal of Advanced Nursing. - : John Wiley & Sons. - 0309-2402 .- 1365-2648. ; 70:10, s. 2373-2388
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: To evaluate the psychometric properties of a questionnaire addressing psychosocial consequences of false-positive mammographic screening.BACKGROUND: The Consequences of Screening - Breast Cancer and Lung Cancer questionnaires target psychosocial consequences of false-positive cancer screening. The Consequences of Screening - Breast Cancer questionnaire and ten items not considered lung cancer specific from the Lung Cancer questionnaire have been adapted for use in mammographic screening in Sweden, but remain psychometrically untested.DESIGN: Instrument development paper with psychometric cross-sectional and test-retest design.METHODS: Twelve scales of a Swedish questionnaire version were tested by the Rasch model and traditional psychometric methods. Women with false-positive (Group I, n = 640) and negative (Group II, n = 802) screening mammography responded to the study questionnaire and the Nottingham Health Profile during 2009-2011.RESULTS: Iterative analyses resulted in nine scales demonstrating Rasch model fit, but all scales exhibited poor targeting with relatively large floor effects. Corrected item-total correlations exceeded the recommended criterion. Score differences between Groups I and II and correlations with Nottingham Health Profile sections followed an expected pattern. Cronbach's α and test-retest reliability was acceptable for group-level assessments for ten and seven scales, respectively.CONCLUSIONS: Five scales (Sense of dejection, Anxiety, Behavioural, Sleep and Existential values) of the Swedish questionnaire version demonstrated the best psychometric properties. Other scales should be used more cautiously. Although filling an important gap, causes of concern were identified across scales. The questionnaire should therefore be considered for group-level assessments rather than for measurement of individual degrees of psychosocial consequences.
  •  
26.
  • Bolejko, Anetta, et al. (författare)
  • Psychometric properties of a Swedish version of the Consequences of Screening : Breast Cancer questionnaire
  • 2014
  • Ingår i: Journal of Advanced Nursing. - : John Wiley & Sons. - 0309-2402 .- 1365-2648. ; 70:10, s. 2373-2388
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: To evaluate the psychometric properties of a questionnaire addressing psychosocial consequences of false-positive mammographic screening. BACKGROUND: The Consequences of Screening--Breast Cancer and Lung Cancer questionnaires target psychosocial consequences of false-positive cancer screening. The Consequences of Screening--Breast Cancer questionnaire and ten items not considered lung cancer specific from the Lung Cancer questionnaire have been adapted for use in mammographic screening in Sweden, but remain psychometrically untested. DESIGN: Instrument development paper with psychometric cross-sectional and test-retest design. METHODS: Twelve scales of a Swedish questionnaire version were tested by the Rasch model and traditional psychometric methods. Women with false-positive (Group I, n = 640) and negative (Group II, n = 802) screening mammography responded to the study questionnaire and the Nottingham Health Profile during 2009-2011. RESULTS: Iterative analyses resulted in nine scales demonstrating Rasch model fit, but all scales exhibited poor targeting with relatively large floor effects. Corrected item-total correlations exceeded the recommended criterion. Score differences between Groups I and II and correlations with Nottingham Health Profile sections followed an expected pattern. Cronbach's α and test-retest reliability was acceptable for group-level assessments for ten and seven scales, respectively. CONCLUSIONS: Five scales (Sense of dejection, Anxiety, Behavioural, Sleep and Existential values) of the Swedish questionnaire version demonstrated the best psychometric properties. Other scales should be used more cautiously. Although filling an important gap, causes of concern were identified across scales. The questionnaire should therefore be considered for group-level assessments rather than for measurement of individual degrees of psychosocial consequences.
  •  
27.
  • Boraka, Öykü, et al. (författare)
  • FGF/FGFR1 system in paired breast tumor-adjacent and tumor tissues, associations with mammographic breast density and tumor characteristics
  • 2023
  • Ingår i: Frontiers in Oncology. - 2234-943X. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • INTRODUCTION: Mammographic breast density (MBD) is an established breast cancer risk factor, yet the underlying molecular mechanisms remain to be deciphered. Fibroblast growth factor receptor 1 (FGFR1) amplification is associated with breast cancer development and aberrant FGF signaling found in the biological processes related to both high mammographic density and breast cancer microenvironment. The aim of this study was to investigate the FGF/FGFR1 expression in-between paired tumor-adjacent and tumor tissues from the same patient, and its associations with MBD and tumor characteristics.METHODS: FGFR1 expression in paired tissues from 426 breast cancer patients participating in the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA) cohort study was analyzed by immunohistochemistry. FGF ligand expression was obtained from RNA-sequencing data for 327 of the included patients.RESULTS: FGFR1 levels were differently expressed in tumor-adjacent and tumor tissues, with increased FGFR1 levels detected in 58% of the tumors. High FGFR1 expression in tumor tissues was associated with less favorable tumor characteristics; high histological grade (OR=1.86, 95% CI 1.00-3.44), high Ki67 proliferative index (OR=2.18, 95% CI 1.18-4.02) as well as tumors of Luminal B-like subtype (OR=2.56, 95%CI 1.29-5.06). While no clear association between FGFR1 expression and MBD was found, FGF ligand (FGF1, FGF11, FGF18) expression was positively correlated with MBD.DISCUSSION: Taken together, these findings support a role of the FGF/FGFR1 system in early breast cancer which warrants further investigation in the MBD-breast cancer context.
  •  
28.
  • Bratt, Ola, 1963, et al. (författare)
  • Population-based Organised Prostate Cancer Testing: Results from the First Invitation of 50-year-old Men
  • 2024
  • Ingår i: European Urology. - 0302-2838 .- 1873-7560. ; 85:3, s. 207-214
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The European Union recently recommended evaluation of the feasibility of organised prostate cancer screening. In Sweden, regional population-based organised prostate cancer testing (OPT) programmes were introduced in 2020. Objective: To describe initial participation rates and diagnostic outcomes. Design, setting, and participants: The three most populated Swedish regions invited all men aged 50 yr to OPT by a letter in 2020–2022. Men with prostate-specific antigen (PSA) ≥3 ng/ml were referred for prostate magnetic resonance imaging (MRI). PSA assays differed across regions. Men with Prostate Imaging Reporting and Data System (PI-RADS) 1–3 and PSA density ≥0.15 ng/ml/cm3 or PI-RADS 4–5 were referred for a biopsy. Data were obtained from the Swedish Register for Organised Prostate Cancer Testing. Outcome measurements and statistical analysis: Overall and regional participation rates, PSA distributions, PI-RADS score distributions, cancer detection, and treatment were evaluated. Results and limitations: A total of 23 855 (35%) of 68 060 invited men participated; 696 (2.9%) had PSA ≥3 ng/ml, and of them, 306 (44%) had a biopsy indication and 221 (32%) had a biopsy. On biopsy, 93 (42%) had Gleason grade group ≥2 (0.39% of PSA-tested men) and 44 (20%) Gleason grade group 1 cancer. Most men with cancer had treatment with curative intent (70%) or were under active surveillance (28%). Across regions, proportions of men with PSA ≥3 ng/ml ranged from 2.3% to 4.0%, and those with PI-RADS score 4–5 ranged from 12% to 21%. A limitation is that results are applicable only to first testing of men in their early 50s. Conclusions: The OPT programmes are feasible with good compliance to the diagnostic pathway. The use of MRI and PSA density avoided a biopsy for over half of the men with PSA ≥3 ng/ml. Inter-regional differences in diagnostic outcomes show a need for standardisation of the diagnostic pathway's components. Patient summary: We report the diagnostic outcomes of inviting 68 000 50-yr-old men to organised prostate cancer testing.
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29.
  • Chaudhry, Nadia, et al. (författare)
  • Breast Cancer Diagnosis Using Extended-Wavelength–Diffuse Reflectance Spectroscopy (EW-DRS) : Proof of Concept in Ex Vivo Breast Specimens Using Machine Learning
  • 2023
  • Ingår i: Diagnostics. - 2075-4418. ; 13:19, s. 1-12
  • Tidskriftsartikel (refereegranskat)abstract
    • This study aims to investigate the feasibility of using diffuse reflectance spectroscopy (DRS) to distinguish malignant breast tissue from adjacent healthy tissue, and to evaluate if an extended-wavelength range (450–1550 nm) has an advantage over the standard wavelength range (450–900 nm). Multivariate statistics and machine learning algorithms, either linear discriminant analysis (LDA) or support vector machine (SVM) are used to distinguish the two tissue types in breast specimens (total or partial mastectomy) from 23 female patients with primary breast cancer. EW-DRS has a sensitivity of 94% and specificity of 91% as compared to a sensitivity of 40% and specificity of 71% using the standard wavelength range. The results suggest that DRS can discriminate between malignant and healthy breast tissue, with improved outcomes using an extended wavelength. It is also possible to construct a simple analytical model to improve the diagnostic performance of the DRS technique.
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30.
  • Cossío, Fernando, et al. (författare)
  • VAI-B: a multicenter platform for the external validation of artificial intelligence algorithms in breast imaging
  • 2023
  • Ingår i: Journal of Medical Imaging. - : SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS. - 2329-4302 .- 2329-4310. ; 10:06
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Multiple vendors are currently offering artificial intelligence (AI) computer-aided systems for triage detection, diagnosis, and risk prediction of breast cancer based on screening mammography. There is an imminent need to establish validation platforms that enable fair and transparent testing of these systems against external data.Approach: We developed validation of artificial intelligence for breast imaging (VAI-B), a platform for independent validation of AI algorithms in breast imaging. The platform is a hybrid solution, with one part implemented in the cloud and another in an on-premises environment at Karolinska Institute. Cloud services provide the flexibility of scaling the computing power during inference time, while secure on-premises clinical data storage preserves their privacy. A MongoDB database and a python package were developed to store and manage the data on-premises. VAI-B requires four data components: radiological images, AI inferences, radiologist assessments, and cancer outcomes.Results: To pilot test VAI-B, we defined a case-control population based on 8080 patients diagnosed with breast cancer and 36,339 healthy women based on the Swedish national quality registry for breast cancer. Images and radiological assessments from more than 100,000 mammography examinations were extracted from hospitals in three regions of Sweden. The images were processed by AI systems from three vendors in a virtual private cloud to produce abnormality scores related to signs of cancer in the images. A total of 105,706 examinations have been processed and stored in the database.Conclusions: We have created a platform that will allow downstream evaluation of AI systems for breast cancer detection, which enables faster development cycles for participating vendors and safer AI adoption for participating hospitals. The platform was designed to be scalable and ready to be expanded should a new vendor want to evaluate their system or should a new hospital wish to obtain an evaluation of different AI systems on their images.
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31.
  • Cossío, Fernando, et al. (författare)
  • VAI-B: A multicenter platform for the external validation of artificial intelligence algorithms in breast imaging
  • 2023
  • Ingår i: Journal of Medical Imaging. - : SPIE-Intl Soc Optical Eng. - 2329-4302 .- 2329-4310. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Multiple vendors are currently offering artificial intelligence (AI) computer-aided systems for triage detection, diagnosis, and risk prediction of breast cancer based on screening mammography. There is an imminent need to establish validation platforms that enable fair and transparent testing of these systems against external data. Approach: We developed validation of artificial intelligence for breast imaging (VAI-B), a platform for independent validation of AI algorithms in breast imaging. The platform is a hybrid solution, with one part implemented in the cloud and another in an on-premises environment at Karolinska Institute. Cloud services provide the flexibility of scaling the computing power during inference time, while secure on-premises clinical data storage preserves their privacy. A MongoDB database and a python package were developed to store and manage the data onpremises. VAI-B requires four data components: radiological images, AI inferences, radiologist assessments, and cancer outcomes. Results: To pilot test VAI-B, we defined a case-control population based on 8080 patients diagnosed with breast cancer and 36,339 healthy women based on the Swedish national quality registry for breast cancer. Images and radiological assessments from more than 100,000 mammography examinations were extracted from hospitals in three regions of Sweden. The images were processed by AI systems from three vendors in a virtual private cloud to produce abnormality scores related to signs of cancer in the images. A total of 105,706 examinations have been processed and stored in the database. Conclusions: We have created a platform that will allow downstream evaluation of AI systems for breast cancer detection, which enables faster development cycles for participating vendors and safer AI adoption for participating hospitals. The platform was designed to be scalable and ready to be expanded should a new vendor want to evaluate their system or should a new hospital wish to obtain an evaluation of different AI systems on their images.
  •  
32.
  • Dahlblom, Victor, et al. (författare)
  • Artificial intelligence detection of missed cancers at digital mammography that were detected at digital breast tomosynthesis
  • 2021
  • Ingår i: Radiology: Artificial Intelligence. - : Radiological Society of North America (RSNA). - 2638-6100. ; 3:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To investigate how an artificial intelligence (AI) system performs at digital mammography (DM) from a screening population with ground truth defined by digital breast tomosynthesis (DBT), and whether AI could detect breast cancers at DM that had originally only been detected at DBT. Materials and Methods: In this secondary analysis of data from a prospective study, DM examinations from 14 768 women (mean age, 57 years), examined with both DM and DBT with independent double reading in the Malmӧ Breast Tomosynthesis Screening Trial (MBTST) (ClinicalTrials.gov: NCT01091545; data collection, 2010–2015), were analyzed with an AI system. Of 136 screening-detected cancers, 95 cancers were detected at DM and 41 cancers were detected only at DBT. The system identifies suspicious areas in the image, scored 1–100, and provides a risk score of 1 to 10 for the whole examination. A cancer was defined as AI detected if the cancer lesion was correctly localized and scored at least 62 (threshold determined by the AI system developers), therefore resulting in the highest examination risk score of 10. Data were analyzed with descriptive statistics, and detection performance was analyzed with receiver operating characteristics. Results: The highest examination risk score was assigned to 10% (1493 of 14 786) of the examinations. With 90.8% specificity, the AI system detected 75% (71 of 95) of the DM-detected cancers and 44% (18 of 41) of cancers at DM that had originally been detected only at DBT. The majority were invasive cancers (17 of 18). Conclusion: Almost half of the additional DBT-only screening-detected cancers in the MBTST were detected at DM with AI. AI did not reach double reading performance; however, if combined with double reading, AI has the potential to achieve a substantial portion of the benefit of DBT screening.
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33.
  • Dahlblom, Victor, et al. (författare)
  • Breast cancer screening with digital breast tomosynthesis : comparison of different reading strategies implementing artificial intelligence
  • 2023
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 33:5, s. 3754-3765
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: Digital breast tomosynthesis (DBT) can detect more cancers than the current standard breast screening method, digital mammography (DM); however, it can substantially increase the reading workload and thus hinder implementation in screening. Artificial intelligence (AI) might be a solution. The aim of this study was to retrospectively test different ways of using AI in a screening workflow.METHODS: An AI system was used to analyse 14,772 double-read single-view DBT examinations from a screening trial with paired DM double reading. Three scenarios were studied: if AI can identify normal cases that can be excluded from human reading; if AI can replace the second reader; if AI can replace both readers. The number of detected cancers and false positives was compared with DM or DBT double reading.RESULTS: By excluding normal cases and only reading 50.5% (7460/14,772) of all examinations, 95% (121/127) of the DBT double reading detected cancers could be detected. Compared to DM screening, 27% (26/95) more cancers could be detected (p < 0.001) while keeping recall rates at the same level. With AI replacing the second reader, 95% (120/127) of the DBT double reading detected cancers could be detected-26% (25/95) more than DM screening (p < 0.001)-while increasing recall rates by 53%. AI alone with DBT has a sensitivity similar to DM double reading (p = 0.689).CONCLUSION: AI can open up possibilities for implementing DBT screening and detecting more cancers with the total reading workload unchanged. Considering the potential legal and psychological implications, replacing the second reader with AI would probably be most the feasible approach.KEY POINTS: • Breast cancer screening with digital breast tomosynthesis and artificial intelligence can detect more cancers than mammography screening without increasing screen-reading workload. • Artificial intelligence can either exclude low-risk cases from double reading or replace the second reader. • Retrospective study based on paired mammography and digital breast tomosynthesis screening data.
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34.
  • Dahlblom, Victor, et al. (författare)
  • Correspondence between areas causing recall in breast cancer screening and artificial intelligence findings
  • 2022
  • Ingår i: 16th International Workshop on Breast Imaging, IWBI 2022. - : SPIE. - 0277-786X .- 1996-756X. - 9781510655843 ; 12286
  • Konferensbidrag (refereegranskat)abstract
    • False positive recall is a major issue in breast cancer screening and the introduction of artificial intelligence (AI) might affect which women who are unnecessarily recalled. We have investigated how an AI system works on false positive recalls at screening and compared with radiologist findings. Two-view digital mammography (DM) examinations from 656 recalled women (136 with screening detected cancer), were analysed with a commercial AI system. The AI findings were matched with the areas on the images causing the recalls. The agreement was studied both at the examination level and for individual findings. Scores were compared between true positive and false positive recalls. ROC analysis was used to study the AI-system's ability to distinguish between true and false positive recalls. It was also studied how the AI system performed on cases where there were discordant readings. AI identified the same areas as radiologists in 80% of the cases recalled on DM. For true positives both the proportion of matching areas and AI scores were higher than for false positive recalls. The AI system also had a relatively large AUC (0.83) for differentiating between false positive recalls and cancers. Further, the AI system identified most of the findings leading to recall in cases where only one of the readers had marked the case for discussion. There is a relatively large agreement between the AI system and radiologists. The AI system scores the false positives lower than true positives. AI complements a single reader in a way similar to a second reader.
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35.
  • Dahlblom, Victor, et al. (författare)
  • Malmö Breast ImaginG database: objectives and development
  • 2023
  • Ingår i: Journal of Medical Imaging. - 2329-4302. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • PurposeWe describe the design and implementation of the Malmö Breast ImaginG (M-BIG) database, which will support research projects investigating various aspects of current and future breast cancer screening programs. Specifically, M-BIG will provide clinical data to: 1. investigate the effect of breast cancer screening on breast cancer prognosis and mortality; 2. develop and validate the use of artificial intelligence and machine learning in breast image interpretation; and 3. develop and validate image-based radiological breast cancer risk profiles.ApproachThe M-BIG database is intended to include a wide range of digital mammography (DM) and digital breast tomosynthesis (DBT) examinations performed on women at the Mammography Clinic in Malmö, Sweden, from the introduction of DM in 2004 through 2020. Subjects may be included multiple times and for diverse reasons. The image data are linked to extensive clinical, diagnostic, and demographic data from several registries.ResultsTo date, the database contains a total of 451,054 examinations from 104,791 women. During the inclusion period, 95,258 unique women were screened. A total of 19,968 examinations were performed using DBT, whereas the rest used DM.ConclusionsWe describe the design and implementation of the M-BIG database as a representative and accessible medical image database linked to various types of medical data. Work is ongoing to add features and curate the existing data.
  •  
36.
  • Dahlblom, Victor, et al. (författare)
  • Personalised breast cancer screening with selective addition of digital breast tomosynthesis through artificial intelligence
  • 2020
  • Ingår i: 15th International Workshop on Breast Imaging, IWBI 2020. - : SPIE. - 0277-786X .- 1996-756X. - 9781510638310 ; 11513
  • Konferensbidrag (refereegranskat)abstract
    • Breast cancer screening is predominantly performed using digital mammography (DM), but higher sensitivity has been demonstrated with digital breast tomosynthesis (DBT). A partial DBT screening in selected groups with a clear benefit from DBT might be more feasible than a full implementation, and using artificial intelligence (AI) to select women for DBT might be a possibility. This study used data from Malmö Breast Tomosynthesis Screening Trial, where all women prospectively were examined with separately read DM and DBT. We retrospectively analysed DM examinations (n=14768) with a breast cancer detection software and used the provided risk score (1-10) for risk stratification. We tested how different score thresholds for adding DBT to an initial DM affects the number of detected cancers, additional DBT examinations needed, detection rate, and false positives. If using a threshold of 9.0, 25 (26 %) more cancers would be detected compared to using DM alone. Of the 41 cancers only detected on DBT, 61 % would be detected, with only 1797 (12 %) of the women examined with both DM and DBT. The detection rate for the added DBT would be 14/1000 women, while the false positive recalls would be increased with 58 (21 %). Using DBT only for selected high gain cases could be an alternative to a complete DBT screening. AI could be used for analysing DM to identify high gain cases, where DBT can be added during the same visit. There might be logistical challenges and further studies in a prospective setting are necessary.
  •  
37.
  • Dahlblom, Victor, et al. (författare)
  • Personalized breast cancer screening with selective addition of digital breast tomosynthesis through artificial intelligence
  • 2023
  • Ingår i: Journal of Medical Imaging. - 2329-4302. ; 10:Suppl 2
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: Breast cancer screening is predominantly performed using digital mammography (DM), but digital breast tomosynthesis (DBT) has higher sensitivity. DBT demands more resources than DM, and it might be more feasible to reserve DBT for women with a clear benefit from the technique. We explore if artificial intelligence (AI) can select women who would benefit from DBT imaging.APPROACH: We used data from Malmö Breast Tomosynthesis Screening Trial, where all women prospectively were examined with separately double read DM and DBT. We retrospectively analyzed DM examinations (n=14768) with a breast cancer detection system and used the provided risk score (1 to 10) for risk stratification. We tested how different score thresholds for adding DBT to an initial DM affects the number of detected cancers, additional DBT examinations needed, detection rate, and false positives.RESULTS: If using a threshold of 9.0, 25 (26%) more cancers would be detected compared to using DM alone. Of the 41 cancers only detected on DBT, 61% would be detected, with only 1797 (12%) of the women examined with both DM and DBT. The detection rate for the added DBT would be 14/1000 women, whereas the false-positive recalls would be increased with 58 (21%).CONCLUSION: Using DBT only for selected high gain cases could be an alternative to complete DBT screening. AI can analyze initial DM images to identify high gain cases where DBT can be added during the same visit. There might be logistical challenges, and further studies in a prospective setting are necessary.
  •  
38.
  • Dahlbäck, Cecilia, et al. (författare)
  • Accuracy of magnetic resonance imaging staging of tumour and nodal stage in rectal cancer treated by primary surgery : a population-based study
  • 2022
  • Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 24:9, s. 1047-1053
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: The preoperative stage of rectal cancer is an important prognostic factor affecting treatment recommendations. Currently, magnetic resonance imaging (MRI) is used for clinical staging to identify patients who should be recommended for neoadjuvant oncological treatment. The aim of this work was to investigate the accuracy of the preoperative T- and N-stage and also involvement of the mesorectal fascia (MRF) as determined by MRI in a Swedish national cohort. Method: Patients who had undergone resectional surgery for rectal cancer without neoadjuvant treatment in Sweden in the period 2013–2017 were identified through the Swedish Colorectal Cancer Registry (n = 2062). The T- and N-stage determined by preoperative MRI were compared with the histopathological results. The MRI-assessed MRF status was compared with the circumferential resection margin. Results: Sensitivity for differentiating T1-2 from T3-4 was 69% and specificity 77%. Sensitivity to detect N1-2 was 42% and specificity 81%. Sensitivity for MRF positivity was 50% and specificity 92%. Agreement analysed by weighted kappa analysis was 0.47 for T-stage [confidence interval (CI) 0.44–0.51], 0.24 for N-stage (CI 0.19–0.24) and 0.20 for MRF status (CI 0.12–0.29). Conclusion: In this study, accuracy of the preoperative MRI was lower than expected for rectal cancers. Overstaging might lead to potentially harmful neoadjuvant treatment and understaging can lead to a higher risk of tumour recurrence. The results of this study show that efforts should be made to increase the accuracy of the preoperative evaluation in order to optimize treatment recommendations.
  •  
39.
  • Dalene Skarping, Ida, et al. (författare)
  • Neoadjuvant breast cancer treatment response; tumor size evaluation through different conventional imaging modalities in the NeoDense study
  • 2020
  • Ingår i: Acta Oncologica. - 1651-226X. ; 59:12, s. 1528-1537
  • Tidskriftsartikel (refereegranskat)abstract
    • Neoadjuvant chemotherapy (NACT) is offered to an increasing number of breast cancer (BC) patients, and comprehensive monitoring of treatment response is of utmost importance. Several imaging modalities are available to follow tumor response, although likely to provide different clinical information. We aimed to examine the association between early radiological response by three conventional imaging modalities and pathological complete response (pCR). Further, we investigated the agreement between these modalities pre-, during, and post-NACT, and the accuracy of predicting pathological residual tumor burden by these imaging modalities post-NACT.
  •  
40.
  • Dustler, Magnus, et al. (författare)
  • Application of the fractal Perlin noise algorithm for the generation of simulated breast tissue
  • 2015
  • Ingår i: Medical Imaging 2015: Physics of Medical Imaging. - : SPIE. - 1996-756X .- 0277-786X. ; 9412, s. 94123-94123
  • Konferensbidrag (refereegranskat)abstract
    • Software breast phantoms are increasingly seeing use in preclinical validation of breast image acquisition systems and image analysis methods. Phantom realism has been proven sufficient for numerous specific validation tasks. A challenge is the generation of suitably realistic small-scale breast structures that could further improve the quality of phantom images. Power law noise follows the noise power characteristics of breast tissue, but may not sufficiently represent certain (e.g., non-Gaussian) properties seen in clinical breast images. The purpose of this work was to investigate the utility of fractal Perlin noise in generating more realistic breast tissue through investigation of its power spectrum and visual characteristics. Perlin noise is an algorithm that creates smoothly varying random structures of an arbitrary frequency. Through the use of a technique known as fractal noise or fractional Brownian motion (fBm), octaves of noise with different frequency are combined to generate coherent noise with a broad frequency range. fBm is controlled by two parameters - lacunarity and persistence - related to the frequency and amplitude of successive octaves, respectively. Average noise power spectra were calculated and beta parameters estimated in sample volumes of fractal Perlin noise with different combinations of lacunarity and persistence. Certain combinations of parameters resulted in noise volumes with beta values between 2 and 3, corresponding to reported measurements in real breast tissue. Different combinations of parameters resulted in different visual appearances. In conclusion, Perlin noise offers a flexible tool for generating breast tissue with realistic properties.
  •  
41.
  • Dustler, Magnus, et al. (författare)
  • Breast compression in mammography: pressure distribution patterns
  • 2012
  • Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 53:9, s. 973-980
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Breast compression is important in mammography in order to improve image quality, better separate tissue components, and reduce absorbed dose to the breast. In this study we use a method to measure and visualize the distribution of pressure over a compressed breast in mammography. Purpose: To measure and describe the pressure distribution over the breast as a result of applied breast compression in mammography. Material and Methods: One hundred and three women aged 40.7-74.3 years (median, 48.9 years) invited for mammographic screening consented to take part in this study. They were subjected to two additional breast compressions of the left breast (standard force and approximately 50% reduction). Pressure images of the compressed breast were obtained using force sensing resistor (FSR) sensors placed underneath the compression plate. Subjects rated their experience of pain on a visual analogue scale (VAS). Results: Four pressure patterns were identified, fitting 81 of the 103 breasts, which were grouped accordingly. The remaining 22 breasts were found to correspond to a combination of any two patterns. Two groups (43 breasts) showed pressure mainly over the juxtathoracic part of the breast, had significantly greater breast thickness (P = 0.003) and had a lower mean pressure over dense tissue (P < 0.0001) than those with more evenly distributed pressure. Reducing compression force increased average breast thickness by 1.8 mm (P < 0.0001). Conclusion: The distribution of pressure differed greatly between breasts. In a large proportion of breasts the compression plate did not provide optimal compression of the breast, the compression force being absorbed in juxtathoracic structures.
  •  
42.
  • Dustler, Magnus, et al. (författare)
  • Can mechanical imaging increase the specificity of mammography screening?
  • 2017
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 27:8, s. 3217-3225
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: This study aimed to investigate the effects of adding adjunct mechanical imaging to mammography breast screening. We hypothesized that mechanical imaging could detect increased local pressure caused by both malignant and benign breast lesions and that a pressure threshold for malignancy could be established. The impact of this on breast screening was investigated with regard to reductions in recall and biopsy rates. Methods: 155 women recalled from breast screening were included in the study, which was approved by the regional ethical review board (dnr 2013/620). Mechanical imaging readings were acquired of the symptomatic breast. The relative mean pressure on the suspicious area (RMPA) was defined and a threshold for malignancy was established. Results: Biopsy-proven invasive cancers had a median RMPA of 3.0 (interquartile range (IQR) = 3.7), significantly different from biopsy-proven benign at 1.3 (IQR = 1.0) and non-biopsied cases at 1.0 (IQR = 1.3) (P < 0.001). The lowest RMPA for invasive cancer was 1.4, with 23 biopsy-proven benign and 33 non-biopsied cases being below this limit. Had these women not been recalled, recall rates would have been reduced by 36% and biopsy rates by 32%. Conclusions: If implemented in a screening situation, this may substantially lower the number of false positives. Key Points: • Mechanical imaging is used as an adjunct to mammography in breast screening.• A threshold pressure can be established for malignant breast cancer.• Recalls and biopsies can be substantially reduced.
  •  
43.
  • Dustler, Magnus, et al. (författare)
  • Distribution of pressure on the breast in mammography using flexible and rigid compression plates : implications on patient handling
  • 2021
  • Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 62:12, s. 1583-1591
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Breast compression in mammography is important but is a source of discomfort and has been linked to screening non-attendance. Reducing compression has little effect on breast thickness, and likely little effect on image quality, due to force being absorbed in the stiff juxta thoracic area instead of in the central breast. Purpose: To investigate whether a flexible compression plate can redistribute force to the central breast and whether this affects perceived pain. Material and Methods: Twenty-eight women recalled from mammography screening were compressed with flexible and rigid plates while retaining force and positioning, 15 in the craniocaudal (CC) view and 13 in the mediolateral oblique (MLO) view. Pressure distribution was continuously measured using pressure sensors. Results: The flexible plate showed greater mean breast pressure in both views: 2.8 versus 2.3 kPa for CC (confidence interval [CI] = 0.2–0.8) and 1.0 versus 0.5 kPa for MLO (CI = 0.2–0.6). The percentage of applied force distributed to the breast was significantly higher with the flexible plate, both on CC (36% vs. 22%, CI = 1–11) and MLO (30% vs. 14%, CI = 4–13). Conclusion: The flexible plate redistributes pressure to the central breast, achieving a better compression, particularly in the MLO view, though much applied force is still applied to the juxta thoracic region.
  •  
44.
  • Dustler, Magnus, et al. (författare)
  • The characteristics of malignant breast tumors imaged using a prototype mechanical imaging system as an adjunct to mammography
  • 2016
  • Ingår i: Breast Imaging : 13th International Workshop, IWDM 2016, Malmö, Sweden, June 19-22, 2016, Proceedings - 13th International Workshop, IWDM 2016, Malmö, Sweden, June 19-22, 2016, Proceedings. - Cham : Springer International Publishing. - 1611-3349 .- 0302-9743. - 9783319415451 - 9783319415468 ; 9699, s. 282-288
  • Konferensbidrag (refereegranskat)abstract
    • Breast cancer is diagnosed by a combination of modalities. Measuring the elasto-mechanical properties of suspicious lesions, by e.g. ultrasound elastography, can help differentiate malignant from benign findings. Using a prototype Mechanical Imaging (MI) system as an adjunct to mammography, the aim of this study was to characterize tumors using MI and compare the readings to those from the contralateral breast. Thirteen bilateral MI sets from women with malignant breast lesions were included in this study, drawn from a larger set of 155 women recalled from screening. The results showed that mean lesion pressure was significantly greater than the mean pressure of the corresponding breast, 7.5 ± 7.0 kPa compared to 2.5 ± 1.6 kPa (P = 0.01). There was no evidence for a difference in mean pressure or standard deviation of the MI image between symptomatic and contralateral asymptomatic breasts (P = 0.24 and 0.68). The results support that it is possible to use MI to distinguish malignant cancers from normal breast tissue. Still, further investigations of the characteristics of benign lesions are necessary to ascertain the usefulness of the system.
  •  
45.
  • Dustler, Magnus, et al. (författare)
  • The effect of breast density on the performance of deep learning-based breast cancer detection methods for mammography
  • 2020
  • Ingår i: 15th International Workshop on Breast Imaging, IWBI 2020. - : SPIE. - 1996-756X .- 0277-786X. - 9781510638310 ; 11513
  • Konferensbidrag (refereegranskat)abstract
    • Mammographic sensitivity in breasts with higher density has been questioned. Higher breast density is also linked to an increased risk for breast cancer. Even though digital breast tomosynthesis (DBT) offers an attractive solution, for varied reasons it has not yet been widely adopted in screening. An alternative could be to boost the performance of standard mammography by using computer-aided detection based on deep learning, but it remains to be proven how such methods are affected by density. A deep-learning based computer-aided detection program was used to score the suspicion of cancer on a scale of 1 to 10. A set of 13838 mammography screening exams were used. All cases had BIRADS density values available. The set included 2304 exams (11 cancers) in BIRADS 1, 5310 (51 cancers) in BIRADS 2, 4844 (73 cancers) in BIRADS 3 and 1223 (22 cancers) in BIRADS 4. A Kruskal-Wallis analysis of variance showed no statistically significant differences between the cancer risk scores of the density categories for cases diagnosed with cancer (P=0.9225). An identical analysis for cases without cancer, showed significant differences between the density categories (P<0.0001). The results suggest that the risk categorization of the deep-learning software is not affected by density, as though some density categories receive higher risk assessments in general, this does not hold for cancer cases, which show uniformly high risk values despite density. This shows the potential for deep-learning to improve screening sensitivity even for women with high density breasts.
  •  
46.
  • Ekelund, Göran, et al. (författare)
  • Population-based screening for colorectal cancer with faecal occult blood test-do we really have enough evidence?
  • 2010
  • Ingår i: International Journal of Colorectal Disease. - : Springer Science and Business Media LLC. - 1432-1262 .- 0179-1958. ; 25, s. 1269-1275
  • Tidskriftsartikel (refereegranskat)abstract
    • INTRODUCTION: Population-based randomised controlled trials (RCT) have shown that invitation to biennial screening with faecal occult blood testing (FOBT) during 10 or more years reduced colorectal cancer-specific mortality. These results have stimulated plans to introduce mass screening in various countries; however, none of these trials has been able to show any reduction of total mortality, which should be expected with reduced disease-specific mortality in a RCT. METHODS: The aim of this review is to analyse, in more detail, the findings in these trials. The results of the trials have, in this review, been systematised and discussed in the context of potential bias, validity and effectiveness. RESULTS: It is found that the reduced cancer-specific mortality is modest and that the clinical significance may be discussed. The number of persons needed to be invited for multiple screening rounds to avoid one death in colorectal cancer (CRC) is high, ranging from about 600 to 1,200. A remarkable finding is that only one fourth of the carcinomas in those invited to the screening were actually detected by this intervention. The absence of reduced total mortality in all series is a serious problem and evokes questions about the validity in determination of cause of death. None of these trials showed any effect on incidence of CRC by removal of precancerous adenomas. CONCLUSIONS: It seems reasonable to conclude that the scientific evidence to support introduction of population-based screening programmes with FOBT appears not yet strong enough. In addition, harm/benefit and cost/effectiveness ratios are not well determined.
  •  
47.
  • Eriksson, Mikael, et al. (författare)
  • Identification of Women at High Risk of Breast Cancer Who Need Supplemental Screening
  • 2020
  • Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 297:2, s. 327-333
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Mammography screening reduces breast cancer mortality, but a proportion of breast cancers are missed and are detected at later stages or develop during between-screening intervals. Purpose To develop a risk model based on negative mammograms that identifies women likely to be diagnosed with breast cancer before or at the next screening examination. Materials and Methods This study was based on the prospective screening cohort Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA), 2011-2017. An image-based risk model was developed by using the Stratus method and computer-aided detection mammographic features (density, masses, microcalcifications), differences in the left and right breasts, and age. The lifestyle extended model included menopausal status, family history of breast cancer, body mass index, hormone replacement therapy, and use of tobacco and alcohol. The genetic extended model included a polygenic risk score with 313 single nucleotide polymorphisms. Age-adjusted relative risks and tumor subtype specific risks were estimated by using logistic regression, and absolute risks were calculated. Results Of 70 877 participants in the KARMA cohort, 974 incident cancers were sampled from 9376 healthy women (mean age, 54 years ± 10 [standard deviation]). The area under the receiver operating characteristic curve (AUC) for the image-based model was 0.73 (95% confidence interval [CI]: 0.71, 0.74). The AUCs for the lifestyle and genetic extended models were 0.74 (95% CI: 0.72, 0.75) and 0.77 (95% CI: 0.75, 0.79), respectively. There was a relative eightfold difference in risk between women at high risk and those at general risk. High-risk women were more likely to be diagnosed with stage II cancers and with tumors 20 mm or larger and were less likely to have stage I and estrogen receptor-positive tumors. The image-based model was validated in three external cohorts. Conclusion By combining three mammographic features, differences in the left and right breasts, and optionally lifestyle factors and family history and a polygenic risk score, the model identified women at high likelihood of being diagnosed with breast cancer within 2 years of a negative screening examination and in possible need of supplemental screening.
  •  
48.
  • Eriksson, Pontus, et al. (författare)
  • Urodrill - a novel MRI-guided endoscopic biopsy technique to sample and molecularly classify muscle-invasive bladder cancer without fractionating the specimen during transurethral resection
  • 2023
  • Ingår i: European Urology Open Science. - 2666-1691. ; 53, s. 78-82
  • Tidskriftsartikel (refereegranskat)abstract
    • The current diagnostic pathway for patients with muscle-invasive bladder cancer (MIBC), which involves with computed tomography urography, cystoscopy, and transurethral resection of the bladder (TURB) to histologically confirm MIBC, delays definitive treatment. The Vesical Imaging-Reporting and Data System (VI-RADS) has been suggested for MIBC identification using magnetic resonance imaging (MRI), but a recent randomized trial reported misclassification in one-third of patients. We investigated a new endoscopic biopsy device (Urodrill) for histological confirmation of MIBC and assessment of molecular subtype by gene expression in patients with VI-RADS 4 and 5 lesions on MRI. In ten patients, Urodrill biopsies were guided by MR images to the muscle-invasive portion of the tumor via a flexible cystoscope under general anesthesia. During the same session, conventional TURB was subsequently performed. A Urodrill sample was successfully obtained in nine of ten patients. MIBC was verified in six of nine patients, and seven of nine samples contained detrusor muscle. In seven of eight patients for whom a Urodrill biopsy sample was subjected to RNA sequencing, single-sample molecular classification according to the Lund taxonomy was feasible. No complications related to the biopsy device occurred. A randomized trial comparing this new diagnostic pathway for patients with VI-RADS 4 and 5 lesions and the current standard (TURB) is warranted. Patient summary: We report on a novel biopsy device for patients with muscle-invasive bladder cancer that facilitates histology analysis and molecular characterization of tumor samples.
  •  
49.
  • Evans, Andrew, et al. (författare)
  • Breast ultrasound : recommendations for information to women and referring physicians by the European Society of Breast Imaging
  • 2018
  • Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 9:4, s. 449-461
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: This article summarises the information that should be provided to women and referring physicians about breast ultrasound (US). After explaining the physical principles, technical procedure and safety of US, information is given about its ability to make a correct diagnosis, depending on the setting in which it is applied. The following definite indications for breast US in female subjects are proposed: palpable lump; axillary adenopathy; first diagnostic approach for clinical abnormalities under 40 and in pregnant or lactating women; suspicious abnormalities at mammography or magnetic resonance imaging (MRI); suspicious nipple discharge; recent nipple inversion; skin retraction; breast inflammation; abnormalities in the area of the surgical scar after breast conserving surgery or mastectomy; abnormalities in the presence of breast implants; screening high-risk women, especially when MRI is not performed; loco-regional staging of a known breast cancer, when MRI is not performed; guidance for percutaneous interventions (needle biopsy, pre-surgical localisation, fluid collection drainage); monitoring patients with breast cancer receiving neo-adjuvant therapy, when MRI is not performed. Possible indications such as supplemental screening after mammography for women aged 40–74 with dense breasts are also listed. Moreover, inappropriate indications include screening for breast cancer as a stand-alone alternative to mammography. The structure and organisation of the breast US report and of classification systems such as the BI-RADS and consequent management recommendations are illustrated. Information about additional or new US technologies (colour-Doppler, elastography, and automated whole breast US) is also provided. Finally, five frequently asked questions are answered. Teaching Points: • US is an established tool for suspected cancers at all ages and also the method of choice under 40. • For US-visible suspicious lesions, US-guided biopsy is preferred, even for palpable findings. • High-risk women can be screened with US, especially when MRI cannot be performed. • Supplemental US increases cancer detection but also false positives, biopsy rate and follow-up exams. • Breast US is inappropriate as a stand-alone screening method.
  •  
50.
  • Fieselmann, Andreas, et al. (författare)
  • Volumetric breast density measurement for personalized screening : Accuracy, reproducibility, and agreement with visual assessment
  • 2018
  • Ingår i: 14th International Workshop on Breast Imaging (IWBI 2018). - : SPIE. - 9781510620070 ; 10718
  • Konferensbidrag (refereegranskat)abstract
    • Assessment of breast density at the point of mammographic examination could lead to optimized breast cancer screening pathways. The onsite breast density information may offer guidance when to recommend supplemental imaging for women in a screening program. In this work, performance evaluation of a new software (Insight BD, Siemens Healthcare GmbH) for fast onsite quantification of volumetric breast density is presented. Accuracy of volumetric measurement is evaluated using breast tissue equivalent phantom experiments. Reproducibility of measurement results is analyzed using 8150 4-view mammography exams. Furthermore, agreement between breast density categories computed by the software with those determined visually by radiologists is examined. The results of the performance evaluation demonstrate that the software delivers accurate and reproducible measurements that agree well with the visual assessment of breast density by radiologists.
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