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| 2. |
- Ericsson, Anders, et al.
(författare)
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Automated interpretation of ventilation-perfusion lung scintigrams for the diagnosis of pulmonary embolism using support vector machines
- 2003
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Ingår i: 13th Scandinavian Conference, SCIA 2003 Halmstad, Sweden, June 29 – July 2, 2003 Proceedings/Lecture Notes in Computer Science. - 0302-9743 .- 1611-3349. - 9783540406013 ; 2749, s. 415-421
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Konferensbidrag (refereegranskat)abstract
- The purpose of this study was to develop a new completely automated method for the interpretation of ventilation-perfusion (V-P) lung scintigrams for the diagnosis of pulmonary embolism. A new way of extracting features, characteristic for pulmonary embolism is presented. These features are then used as input to a Support Vector Machine, which discriminates between pulmonary embolism or no embolism. Using a material of 509 training cases and 104 test cases, the performance of the system, measured as the area under the ROC curve, was 0.86 in the test group. It is concluded that a completely automatic method can be used for interpretation of V-P scintigrams. It is faster and more robust than a previously presented method [4,5] and the accuracy is at the same level as the the previous method. It also handles abnormalities in the lungs.
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| 3. |
- Evander, Eva, et al.
(författare)
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Role of ventilation scintigraphy in diagnosis of acute pulmonary embolism: an evaluation using artificial neural networks.
- 2003
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 30:7, s. 961-965
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to assess the value of the ventilation study in the diagnosis of acute pulmonary embolism using a new automated method. Either perfusion scintigrams alone or two different combinations of ventilation/perfusion scintigrams were used as the only source of information regarding pulmonary embolism. A completely automated method based on computerised image processing and artificial neural networks was used for the interpretation. Three artificial neural networks were trained for the diagnosis of pulmonary embolism. Each network was trained with 18 automatically obtained features. Three different sets of features originating from three sets of scintigrams were used. One network was trained using features obtained from each set of perfusion scintigrams, including six projections. The second network was trained using features from each set of (joint) ventilation and perfusion studies in six projections. A third network was trained using features from the perfusion study in six projections combined with a single ventilation image from the posterior view. A total of 1,087 scintigrams from patients with suspected pulmonary embolism were used for network training. The test group consisted of 102 patients who had undergone both scintigraphy and pulmonary angiography. Performances in the test group were measured as area under the receiver operation characteristic curve. The performance of the neural network in interpreting perfusion scintigrams alone was 0.79 (95% confidence limits 0.71–0.86). When one ventilation image (posterior view) was added to the perfusion study, the performance was 0.84 (0.77–0.90). This increase was statistically significant (P=0.022). The performance increased to 0.87 (0.81–0.93) when all perfusion and ventilation images were used, and the increase in performance from 0.79 to 0.87 was also statistically significant (P=0.016). The automated method presented here for the interpretation of lung scintigrams shows a significant increase in performance when one or all ventilation images are added to the six perfusion images. Thus, the ventilation study has a significant role in the diagnosis of acute lung embolism.
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| 4. |
- Garpered, Sabine, et al.
(författare)
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Measurement of airway inflammation in current smokers by positron emission tomography
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 39:6, s. 393-398
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Tidskriftsartikel (refereegranskat)abstract
- Background Accumulation of activated neutrophilic leucocytes is known to increase uptake of F-18-fluorodeoxyglucose (F-18-FDG) into lung tissue. Available evidence suggests that smokers and subjects with chronic obstructive pulmonary disease (COPD) have neutrophilic inflammation in peripheral airways. The aim of this study was to examine whether current smokers have higher lung tissue uptake of F-18-FDG than never-smokers when correcting for air fraction of the lungs. Methods We prospectively recruited 33 current smokers and 33 never-smokers among subjects referred for diagnosis or staging of cancer, other than lung cancer, with combined positron emission tomography/computed tomography (PET/CT) with F-18-FDG. Subjects with focal F-18-FDG uptake or focal CT abnormalities in the lungs were excluded. The lungs were segmented in the CT image, and lung density measured. F-18-FDG uptake was measured in the corresponding volume and corrected for air fraction. Results Lung uptake of F-18-FDG, corrected for air fraction, was 12 center dot 5 and 8 per cent higher in the right and left lungs, respectively, in current smokers than in never-smokers (P<0 center dot 05). Conclusion Abnormal lung tissue uptake of F-18-FDG may be masked by reduced lung density if the uptake is not related to air fraction. Increased uptake of F-18-FDG in lung tissue in current smokers relative to never-smokers may reflect inflammation in peripheral airways. Measurements of F-18-FDG uptake in the lung tissue may be useful for animal and human studies of airways disease in COPD and the relation between airway and systemic inflammation.
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| 5. |
- Ly, John, et al.
(författare)
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Semi-automatic analysis of standard uptake values in serial PET/CT studies in patients with lung cancer and lymphoma
- 2012
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Ingår i: BMC Medical Imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Changes in maximum standardised uptake values (SUVmax) between serial PET/CT studies are used to determine disease progression or regression in oncologic patients. To measure these changes manually can be time consuming in a clinical routine. A semi-automatic method for calculation of SUVmaxin serial PET/CT studies was developed and compared to a conventional manual method. The semi-automatic method first aligns the serial PET/CT studies based on the CT images. Thereafter, the reader selects an abnormal lesion in one of the PET studies. After this manual step, the program automatically detects the corresponding lesion in the other PET study, segments the two lesions and calculates the SUVmaxin both studies as well as the difference between the SUVmaxvalues. The results of the semi-automatic analysis were compared to that of a manual SUVmaxanalysis using a Philips PET/CT workstation. Three readers did the SUVmaxreadings in both methods. Sixteen patients with lung cancer or lymphoma who had undergone two PET/CT studies were included. There were a total of 26 lesions.Results: Linear regression analysis of changes in SUVmaxshow that intercepts and slopes are close to the line of identity for all readers (reader 1: intercept = 1.02, R2= 0.96; reader 2: intercept = 0.97, R2= 0.98; reader 3: intercept = 0.99, R2= 0.98). Manual and semi-automatic method agreed in all cases whether SUVmaxhad increased or decreased between the serial studies. The average time to measure SUVmaxchanges in two serial PET/CT examinations was four to five times longer for the manual method compared to the semi-automatic method for all readers (reader 1: 53.7 vs. 10.5 s; reader 2: 27.3 vs. 6.9 s; reader 3: 47.5 vs. 9.5 s; p < 0.001 for all).Conclusions: Good agreement was shown in assessment of SUVmaxchanges between manual and semi-automatic method. The semi-automatic analysis was four to five times faster to perform than the manual analysis. These findings show the feasibility of using semi-automatic methods for calculation of SUVmaxin clinical routine and encourage further development of programs using this type of methods. © 2012 Ly et al; licensee BioMed Central Ltd.
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| 6. |
- Ly, John, et al.
(författare)
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The use of a proposed updated EARL harmonization of 18F-FDG PET-CT in patients with lymphoma yields significant differences in Deauville score compared with current EARL recommendations
- 2019
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Ingår i: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Deauville score (DS) is a clinical tool, based on the comparison between lesion and reference organ uptake of 18F-fluorodeoxyglucose (FDG), used to stratify patients with lymphoma into categories reflecting their disease status. With a plethora of positron emission tomography with computed tomography (PET-CT) hard- and software algorithms, standard uptake value (SUV) in lesions and reference organs may differ which affects DS classification and therefore medical treatment. The EANM Research Ltd. (EARL) harmonization program from the European Association of Nuclear Medicine (EANM) partly mitigates this issue, but local preferences are common in clinical practice. We have investigated the discordance in DS calculated from patients with lymphoma referred for 18F-FDG PET-CT reconstructed with three different algorithms: the newly introduced block-sequential regularization expectation-maximization algorithm commercially sold as Q. Clear (QC, GE Healthcare, Milwaukee, WI, USA), compliant with the newly proposed updated EARL recommendations, and two settings compliant with the current EARL recommendations (EARLlower and EARLupper, representing the lower and upper limit of the EARL recommendations). Methods: Fifty-two patients with non-Hodgkin and Hodgkin lymphoma were included (18 females and 34 males). Segmentation of mediastinal blood pool and liver were semi-automatically performed, whereas segmentation of lesions was done manually. From these segmentations, SUVmax and SUVpeak were obtained and DS calculated. Results: There was a significant difference in DS between the QC algorithm and EARLlower/EARLupper (p < 0.0001 for both) but not between EARLlower and EARLupper (p = 0.102) when SUVmax was used. For SUVpeak, there was a significant difference between QC and EARLlower (p = 0.001), but not for QC vs EARLupper (p = 0.071) or EARLlower vs EARLupper (p = 0.102). Five non-responders (DS 4–5) for QC were classified as responders (DS 1–3) when EARLlower/EARLupper was used, both when SUVmax and SUVpeak were investigated. Conclusion: Using the proposed updated EARL recommendations compared with the current recommendations will significantly change DS classification. In select cases, the discordance would affect the choice of medical treatment. Specifically, the current EARL recommendations were more often prone to classify patients as responders.
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| 7. |
- Minarik, David, et al.
(författare)
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Perfusion vector-a new method to quantify myocardial perfusion scintigraphy images: a simulation study with validation in patients.
- 2015
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Ingår i: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The interpretation of myocardial perfusion scintigraphy (MPS) largely relies on visual assessment by the physician of the localization and extent of a perfusion defect. The aim of this study was to introduce the concept of the perfusion vector as a new objective quantitative method for further assisting the visual interpretation and to test the concept using simulated MPS images as well as patients.
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| 8. |
- Reza Felix, Mariana, et al.
(författare)
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Bone Scan Index and Progression-free Survival Data for Progressive Metastatic Castration-resistant Prostate Cancer Patients Who Received ODM-201 in the ARADES Multicentre Study
- 2016
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Ingår i: European Urology Focus. - : Elsevier BV. - 2405-4569. ; 2:5, s. 547-552
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Tidskriftsartikel (refereegranskat)abstract
- Background ODM-201, a new-generation androgen receptor inhibitor, has shown clinical efficacy in prostate cancer (PCa). Quantitative methods are needed to accurately assess changes in bone as a measurement of treatment response. The Bone Scan Index (BSI) reflects the percentage of skeletal mass a given tumour affects. Objective To evaluate the predictive value of the BSI in metastatic castration-resistant PCa (mCRPC) patients undergoing treatment with ODM-201. Design, setting, and participants From a total of 134 mCRPC patients who participated in the Activity and Safety of ODM-201 in Patients with Progressive Metastatic Castration-resistant Prostate Cancer clinical trial and received ODM-201, we retrospectively selected all those patients who had bone scan image data of sufficient quality to allow for both baseline and 12-wk follow-up BSI-assessments (n = 47). We used the automated EXINI bone BSI software (EXINI Diagnostics AB, Lund, Sweden) to obtain BSI data. Outcome measurements and statistical analysis We used the Cox proportional hazards model and Kaplan-Meier estimates to investigate the association among BSI, traditional clinical parameters, disease progression, and radiographic progression-free survival (rPFS). Results and limitations In the BSI assessments, at follow-up, patients who had a decrease or at most a 20% increase from BSI baseline had a significantly longer time to progression in bone (median not reached vs 23 wk, hazard ratio [HR]: 0.20; 95% confidence interval [CI], 0.07–0.58; p = 0.003) and rPFS (median: 50 wk vs 14 wk; HR: 0.35; 95% CI, 0.17–0.74; p = 0.006) than those who had a BSI increase >20% during treatment. Conclusions The on-treatment change in BSI was significantly associated with rPFS in mCRPC patients, and an increase >20% in BSI predicted reduced rPFS. BSI for quantification of bone metastases may be a valuable complementary method for evaluation of treatment response in mCRPC patients. Patient summary An increase in Bone Scan Index (BSI) was associated with shorter time to disease progression in patients treated with ODM-201. BSI may be a valuable method of complementing treatment response evaluation in patients with advanced prostate cancer.
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| 9. |
- Reza Felix, Mariana, et al.
(författare)
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Bone Scan Index as an Imaging Biomarker in Metastatic Castration-resistant Prostate Cancer : A Multicentre Study Based on Patients Treated with Abiraterone Acetate (Zytiga) in Clinical Practice
- 2016
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Ingår i: European Urology Focus. - : Elsevier BV. - 2405-4569. ; 2:5, s. 540-546
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Tidskriftsartikel (refereegranskat)abstract
- Background Abiraterone acetate (AA) prolongs survival in metastatic castration-resistant prostate cancer (mCRPC) patients. To measure treatment response accurately in bone, quantitative methods are needed. The Bone Scan Index (BSI), a prognostic imaging biomarker, reflects the tumour burden in bone as a percentage of the total skeletal mass calculated from bone scintigraphy. Objective To evaluate the value of BSI as a biomarker for outcome evaluation in mCRPC patients on treatment with AA according to clinical routine. Design, setting, and participants We retrospectively studied 104 mCRPC patients who received AA following disease progression after chemotherapy. All patients underwent whole-body bone scintigraphy before and during AA treatment. Baseline and follow-up BSI data were obtained using EXINI BoneBSI software (EXINI Diagnostics AB, Lund, Sweden). Outcome measurements and statistical analysis Associations between change in BSI, clinical parameters at follow-up, and overall survival (OS) were evaluated using the Cox proportional hazards regression models and Kaplan-Meier estimates. Discrimination between variables was assessed using the concordance index (C-index). Results and limitations Patients with an increase in BSI at follow-up of at most 0.30 (n = 54) had a significantly longer median survival time than those with an increase of BSI >0.30 (n = 50) (median: 16 vs 10 mo; p = 0.001). BSI change was also associated with OS in a multivariate Cox analysis including commonly used clinical parameters for prognosis (C-index = 0.7; hazard ratio: 1.1; p = 0.03). The retrospective design was a limitation. Conclusions Change in BSI was significantly associated with OS in mCRPC patients undergoing AA treatment following disease progression in a postchemotherapy setting. BSI may be a useful imaging biomarker for outcome evaluation in this group of patients, and it could be a valuable complementary tool in monitoring patients with mCRPC on second-line therapies. Patient summary Bone Scan Index (BSI) change is related to survival time in metastatic castration-resistant prostate cancer (mCRPC) patients on abiraterone acetate. BSI may be a valuable complementary decision-making tool supporting physicians monitoring patients with mCRPC on second-line therapies.
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| 10. |
- Reza, Mariana, et al.
(författare)
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Automated Bone Scan Index as an Imaging Biomarker to Predict Overall Survival in the Zometa European Study/SPCG11
- 2021
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Ingår i: European Urology Oncology. - : Elsevier BV. - 2588-9311. ; 4:1, s. 49-55
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Owing to the large variation in treatment response among patients with high-risk prostate cancer, it would be of value to use objective tools to monitor the status of bone metastases during clinical trials. Automated Bone Scan Index (aBSI) based on artificial intelligence has been proposed as an imaging biomarker for the quantification of skeletal metastases from bone scintigraphy.OBJECTIVE: To investigate how an increase in aBSI during treatment may predict clinical outcome in a randomised controlled clinical trial including patients with high-risk prostate cancer.DESIGN, SETTING, AND PARTICIPANTS: We retrospectively selected all patients from the Zometa European Study (ZEUS)/SPCG11 study with image data of sufficient quality to allow for aBSI assessment at baseline and at 48-mo follow-up. Data on aBSI were obtained using EXINIboneBSI software, blinded for clinical data and randomisation of zoledronic acid treatment. Data on age, overall survival (OS), and prostate-specific antigen (PSA) at baseline and upon follow-up were available from the study database.OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Association between clinical parameters and aBSI increase during treatment was evaluated using Cox proportional-hazards regression models, Kaplan-Meier estimates, and log-rank test. Discrimination between prognostic variables was assessed using the concordance index (C-index).RESULTS AND LIMITATIONS: In this cohort, 176 patients with bone metastases and a change in aBSI from baseline to follow-up of ≤0.3 had a significantly longer median survival time than patients with an aBSI change of >0.3 (p<0.0001). The increase in aBSI was significantly associated with OS (p<0.01 and C-index=0.65), while age and PSA change were not.CONCLUSIONS: The aBSI used as an objective imaging biomarker predicted outcome in prostate cancer patients in the ZEUS/SPCG11 study. An analysis of the change in aBSI from baseline to 48-mo follow-up represents a valuable tool for prognostication and monitoring of prostate cancer patients with bone metastases.PATIENT SUMMARY: The increase in the burden of skeletal metastases, as measured by the automated Bone Scan Index (aBSI), during treatment was associated with overall survival in patients from the Zometa European Study/SPCG11 study. The aBSI may be a useful tool also in monitoring prostate cancer patients with newly developed bone metastases.
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