| 1. |
- Almlöv, Karin, et al.
(författare)
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MRI Lymph Node Evaluation for Prediction of Metastases in Rectal Cancer
- 2020
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Ingår i: Anticancer Research. - : International Institute of Anticancer Research. - 0250-7005 .- 1791-7530. ; 40:5, s. 2757-2763
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To explore whether the size and characteristics of the largest regional lymph node in patients with rectal cancer, based on magnetic resonance imaging (MRI), following neoadjuvant therapy and before surgery, is able to identify patients at high risk of developing metachronous metastases.Patients and Methods: A retrospective case–control study with data from the Swedish Colo-Rectal Cancer Registry. Forty patients were identified with metachronous metastases (M+), and 40 patients without metastases (M0) were matched as controls.Results: Patients with M+ disease were more likely to have a regional lymph node measuring ≥5 mm than patients with M0. (87% vs. 65%, p=0.02). There was also a significant difference between the groups regarding the presence of an irregular border of the largest lymph node (68% vs. 40%, p=0.01).Conclusion: Lymph nodes measuring ≥5 mm with/without displaying irregular borders at MRI performed after neoadjuvant therapy emerged as risk factors for metachronous metastases in patients with rectal cancer. Intensified follow-up programmes may be indicated in these patients.
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| 2. |
- Bivik Stadler, Caroline, 1986-, et al.
(författare)
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Proactive Construction of an Annotated Imaging Database for Artificial Intelligence Training
- 2021
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Ingår i: Journal of digital imaging. - : Springer-Verlag New York. - 0897-1889 .- 1618-727X. ; 34, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- Artificial intelligence (AI) holds much promise for enabling highly desired imaging diagnostics improvements. One of the most limiting bottlenecks for the development of useful clinical-grade AI models is the lack of training data. One aspect is the large amount of cases needed and another is the necessity of high-quality ground truth annotation. The aim of the project was to establish and describe the construction of a database with substantial amounts of detail-annotated oncology imaging data from pathology and radiology. A specific objective was to be proactive, that is, to support undefined subsequent AI training across a wide range of tasks, such as detection, quantification, segmentation, and classification, which puts particular focus on the quality and generality of the annotations. The main outcome of this project was the database as such, with a collection of labeled image data from breast, ovary, skin, colon, skeleton, and liver. In addition, this effort also served as an exploration of best practices for further scalability of high-quality image collections, and a main contribution of the study was generic lessons learned regarding how to successfully organize efforts to construct medical imaging databases for AI training, summarized as eight guiding principles covering team, process, and execution aspects.
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| 3. |
- Björkman, Ann-Sofi, 1983-, et al.
(författare)
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Mobile learning device increased study efficiency for radiology residents but with risk of temporary novelty effect
- 2019
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Ingår i: Acta Radiologica Open. - : Sage Publications. - 2058-4601. ; 8:11, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Digital resources in learning are increasingly available and offer new possibilities in education. Mobile learning devices (MLD) such as tablets provide easy and flexible access for users.Purpose: To investigate whether the introduction of MLDs in radiology education affected time spent on studies over a longer time frame and whether learning behavior and attitudes changed.Material and Methods: The radiology residents employed during 2015–2016 were invited to participate in this 12-month MLD intervention study. Results were evaluated using online questionnaires at six months (6 m) and 12 months (12 m).Results: Thirty-one residents were included, of whom half were in the early stages of residency (<2 years). After the MLD introduction, most participants (91% [6 m] and 83% [12 m]) estimated increased time spent on studies. Of these, 32% stated “a lot more” at 6 m but only 8% at 12 m (P ¼ 0.12). The MLDs showed positive effects on the experience of radiology studies, as a majority of participants stated better quality and effectiveness in their studies (100% [6 m]–92% [12 m]), that MLD facilitated access to educational materials to a high degree (83% [6 m]–75% [12 m]), and that studies had become better and more fun (96% [6 m]–100% [12 m]).Conclusion: The use of MLDs seems to facilitate learning effectively for radiologic residents. However, a larger scale study is required as a trend of decreasing figures in the longer term was seen, but our results did not show a significant reduction of time spent on radiology studies.
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| 4. |
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| 5. |
- Falk, Magnus, et al.
(författare)
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Modifierad brittisk modell kortade ledtid till datortomografi av kolon
- 2015
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Ingår i: Läkartidningen. - Stockholm, Sweden : Läkartidningen Förlag AB. - 0023-7205 .- 1652-7518. ; 112
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Tidskriftsartikel (refereegranskat)abstract
- The British national Institute for Health and Care Excellence (NICE) has presented guidelines based on signs and symptoms which should raise a suspicion of colorectal cancer. A slightly modified version of these guidelines, adapted to Swedish conditions, named Swedish NICE (sNICE) criteria, was implemented at eight primary care centres. By following the sNICE criteria, cases with higher degree of suspicion of colorectal cancer were advised for computer tomography (CT) of the colon, whereas cases of low degree of suspicion were advised for the considerably less time and patient demanding CT of the abdomen. For patients with isolated anal symptoms without presence of sNICE criteria, active expectancy for six weeks was recommended, followed by renewed consideration. Results showed that the ratio between CT colon and CT abdomen was reduced from 2.2 to 1.1 after introduction of the sNICE criteria. Also, the proportion of patients undergoing CT colon within two weeks from admittance was increased from 3 to 25 %. We conclude that the sNICE criteria may be a useful supportive tool for the primary care physician.
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| 6. |
- Henriksson, Lilian, et al.
(författare)
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The transluminal attenuation gradient does not add diagnostic accuracy to coronary computed tomography
- 2021
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Ingår i: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; , s. 867-874
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Tidskriftsartikel (refereegranskat)abstract
- Background A method for improving the accuracy of coronary computed tomography angiography (CCTA) is highly sought after as it would help to avoid unnecessary invasive coronary angiographies. Measurement of the transluminal attenuation gradient (TAG) has been proposed as an alternative to other existing methods, i.e. CT perfusion and CT fractional flow reserve (FFR). Purpose To evaluate the incremental value of three types of TAG in high-pitch spiral CCTA with invasive FFR measurements as reference. Material and Methods TAG was measured using two semi-automatic methods and one manual method. A receiver operating characteristic (ROC) analysis was made to determine the usefulness of TAG alone as well as TAG combined with CCTA for detection of significant coronary artery stenoses defined by an invasive FFR value <= 0.80. Results A total of 51 coronary vessels in 37 patients were included in this retrospective study. Hemodynamically significant stenoses were found in 13 vessels according to FFR. The ROC analysis TAG alone resulted in areas under the curve (AUCs) of 0.530 and 0.520 for the semi-automatic TAG and 0.557 for the manual TAG. TAG and CCTA combined resulted in AUCs of 0.567, 0.562 for semi-automatic TAG, and 0.569 for the manual TAG. Conclusion The results from our study showed no incremental value of TAG measured in single heartbeat CCTA in determining the severity of coronary artery stenosis degrees.
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| 7. |
- Kalra, Mannudeep K., et al.
(författare)
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Radiation Dose Reduction with Sinogram Affirmed Iterative Reconstruction Technique for abdominal Computer Tomography
- 2012
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Ingår i: Journal of Computer Assisted Tomography. - USA : Lippincott Williams & Wilkins. - 0363-8715. ; 36:3, s. 339-346
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The objective of this study was to assess the effect of Sinogram Affirmed Iterative Reconstruction (SAFIRE) and filtered back-projection (FBP) techniques on abdominal computed tomography (CT) performed with 50% and 75% radiation dose reductions.Methods: Twenty-four patients (mean age, 64 ± 14 years; male-female ratio, 10:14) gave informed consent for an institutional review board–approved prospective study involving acquisition of additional research images through the abdomen on 128-slice multi–detector-row CT (SOMATOM Definition Flash) at quality reference mAs of 100 (50% lower dose) and 50 (75% lower dose) over a scan length of 10 cm using combined modulation (CARE Dose 4D). Standard-of-care abdominal CT was performed at 200 quality reference mAs, with remaining parameters held constant. The 50- and 100-mAs data sets were reconstructed with FBP and at 4 SAFIRE settings (S1, S2, S3, S4). Higher number of SAFIRE settings denotes increased strength of the algorithm resulting in lower image noise. Two abdominal radiologists independently compared the FBP and SAFIRE images for lesion number, location, size and conspicuity, and visibility of small structures, image noise, and diagnostic confidence. Objective noise and Hounsfield units (HU) were measured in the liver and the descending aorta.Results: All 43 lesions were detected on both FBP and SAFIRE images. Minor blocky, pixelated appearance of 50% and 75% reduced dose images was noted at S3 and S4 SAFIRE but not at S1 and S2 settings. Subjective noise was suboptimal in both 50% and 75% lower-dose FBP images but was deemed acceptable on all SAFIRE settings. Sinogram Affirmed Iterative Reconstruction images were deemed acceptable in all patients at 50% lower dose and in 22 of 24 patients at 75% lower dose. As compared with 75% reduced dose FBP, objective noise was lower by 22.8% (22.9/29.7), 35% (19.3/29.7), 44.3% (16.7/29.3), and 54.8% (13.4/29.7) on S1 to S4 settings, respectively (P < 0.001).Conclusions: Sinogram Affirmed Iterative Reconstruction–enabled reconstruction provides abdominal CT images without loss in diagnostic value at 50% reduced dose and in some patients also at 75% reduced dose.
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| 8. |
- Kalra, Mannudeep K., et al.
(författare)
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Sinogram-Affirmed Iterative Reconstruction of Low-Dose Chest CT: Effect on Image Quality and Radiation Dose
- 2013
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Ingår i: American Journal of Roentgenology. - : American Roentgen Ray Society (ARRS). - 0361-803X .- 1546-3141. ; 201:2, s. W235-W244
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. The purpose of this study is to compare sinogram-affirmed iterative reconstruction (SAFIRE) and filtered back projection (FBP) reconstruction of chest CT acquired with 65% radiation dose reduction.SUBJECTS AND METHODS. In this prospective study involving 24 patients (11 women and 13 men; mean [+/- SD] age, 66 +/- 10 years), two scan series were acquired using 100 and 40 Quality Reference mAs over a 10-cm scan length in the chest with a 128-MDCT scanner. The 40 Quality Reference mAs CT projection data were reconstructed with FBP and four settings of Safire (S1, S2, S3, and S4). Six image datasets (FBP with 100 and 40 Quality Reference mAs, and S1, S2, S3, S4 with 40 Quality Reference mAs) were displayed on a DICOM-compliant 55-inch 2-megapixel monitor for blinded evaluation by two thoracic radiologists for number and location of lesions, lesion size, lesion margins, visibility of small structures and fissures, and diagnostic confidence. Objective noise and CT values were measured in thoracic aorta for each image series, and the noise power spectrum was assessed. Data were analyzed with analysis of variance and Wilcoxon signed rank tests.RESULTS. All 186 lesions were seen on 40 Quality Reference mAs SAFIRE images. Diagnostic confidence on SAFIRE images was higher than that for FBP images. Except for the minor blotchy appearance on SAFIRE settings S3 and S4, no significant artifacts were noted. Objective noise with 40 Quality Reference mAs S1 images (21.1 +/- 6.1 SD of HU) was significantly lower than that for 40 Quality Reference mAs FBP images (28.5 +/- 8.1 SD of HU) (p andlt; 0.001). Noise power spectra were identical for SAFIRE and FBP with progressive noise reduction with higher iteration SAFIRE settings.CONCLUSION. Iterative reconstruction (SAFIRE) allows reducing the radiation exposure by approximately 65% without losing diagnostic information in chest CT.
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| 9. |
- Kataria, Bharti, 1955-, et al.
(författare)
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Image quality in CT thorax: effect of altering reconstruction algorithm and tube load : Image quality in CT thorax
- 2024
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press. - 0144-8420 .- 1742-3406. ; 200:5, s. 504-514
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Tidskriftsartikel (refereegranskat)abstract
- Non-linear properties of iterative reconstruction (IR) algorithms can alter image texture. We evaluated the effect of a model-basedIR algorithm (advanced modelled iterative reconstruction; ADMIRE) and dose on computed tomography thorax image quality.Dual-source scanner data were acquired at 20, 45 and 65 reference mAs in 20 patients. Images reconstructed with filteredback projection (FBP) and ADMIRE Strengths 3–5 were assessed independently by six radiologists and analysed using an ordinallogistic regression model. For all image criteria studied, the effects of tube load 20 mAs and all ADMIRE strengths were significant(p < 0.001) when compared to reference categories 65 mAs and FBP. Increase in tube load from 45 to 65 mAs showed imagequality improvement in three of six criteria. Replacing FBP with ADMIRE significantly improves perceived image quality for allcriteria studied, potentially permitting a dose reduction of almost 70% without loss in image quality
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| 10. |
- Klintström, Benjamin, et al.
(författare)
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Photon-counting detector CT and energy-integrating detector CT for trabecular bone microstructure analysis of cubic specimens from human radius
- 2022
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Ingår i: European radiology experimental. - : Springer Nature. - 2509-9280. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Background As bone microstructure is known to impact bone strength, the aim of this in vitro study was to evaluate if the emerging photon-counting detector computed tomography (PCD-CT) technique may be used for measurements of trabecular bone structures like thickness, separation, nodes, spacing and bone volume fraction. Methods Fourteen cubic sections of human radius were scanned with two multislice CT devices, one PCD-CT and one energy-integrating detector CT (EID-CT), using micro-CT as a reference standard. The protocols for PCD-CT and EID-CT were those recommended for inner- and middle-ear structures, although at higher mAs values: PCD-CT at 450 mAs and EID-CT at 600 (dose equivalent to PCD-CT) and 1000 mAs. Average measurements of the five bone parameters as well as dispersion measurements of thickness, separation and spacing were calculated using a three-dimensional automated region growing (ARG) algorithm. Spearman correlations with micro-CT were computed. Results Correlations with micro-CT, for PCD-CT and EID-CT, ranged from 0.64 to 0.98 for all parameters except for dispersion of thickness, which did not show a significant correlation (p = 0.078 to 0.892). PCD-CT had seven of the eight parameters with correlations rho > 0.7 and three rho > 0.9. The dose-equivalent EID-CT instead had four parameters with correlations rho > 0.7 and only one rho > 0.9. Conclusions In this in vitro study of radius specimens, strong correlations were found between trabecular bone structure parameters computed from PCD-CT data when compared to micro-CT. This suggests that PCD-CT might be useful for analysing bone microstructure in the peripheral human skeleton.
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