PURPOSE:The purpose of this study was to compare, across readers with varying experience, the characterisation of prostate MRI lesions as grade group (GG) ≥ 2 cancer, by using the PI-RADS version 2.1 (PI-RADSv2.1) score alone and by combining prostate specific antigen density (PSAd), the PI-RADSv2.1 score and the output of a radiomics-based algorithm (Q-CAD). MATERIALS AND METHODS:The MULTI database in which 21 readers (seven experienced seniors, seven less-experienced seniors, seven juniors) had assigned a PI-RADSv2.1 score to 240 prostate MRI lesions was retrospectively used. The lesions were outlined by two independent experts to compute their Q-CAD score. For each reader, four biopsy strategies were simulated. PI-RADS3 and PI-RADS4 strategies triggered biopsy in PI-RADSv2.1 ≥ 3 and PI-RADSv2.1 ≥ 4 lesions respectively. Combined3 and Combined4 strategies triggered biopsy when at least two of the following conditions were fulfilled: positive PI-RADSv2.1 score (≥ 3 for Combined3; ≥ 4 for Combined4), positive Q-CAD score (≥ 0.45 in peripheral zone; ≥ 0.79 in transition zone), PSAd ≥ 0.15 ng/mL/cm3. RESULTS:A total of 232 lesions were included. Using lesions' delineations by Expert 1 for the three readers' experience groups, the Combined3 strategy was significantly less sensitive for GG ≥ 2 cancers (87-88% vs. 91-96%; P = 0.026 to < 0.001), but significantly more specific (45%-55% vs. 15%-34%; P < 0.001) than the PI-RADS3 strategy. The Combined4 strategy was less sensitive than the PI-RADS4 strategy (84%-86% vs. 85%-91%) but the difference was significant only for less-experienced seniors (P = 0.023); it was significantly more specific (51%-63% vs. 27%-50%; P < 0.001) in all groups. The Combined4 strategy provided the highest net benefit for risk thresholds >12%-16%. Using lesions' delineations by Expert 2 yielded similar results. CONCLUSION:The combined strategies significantly increased specificity, at the cost of slightly reducing sensitivity for GG ≥ 2 cancers.
PURPOSE:The purpose of this study was to compare the image quality and lesion detection between ultra-low dose (ULD) chest-abdomen-pelvis computed tomography (CAP-CT) reconstructed with a deep-learning image reconstruction (DLR) algorithm, and standard-dose CT (STD-CT) in cancer follow-up. MATERIALS AND METHODS:A total of 106 patients undergoing CAP-CT for the follow-up of cancer were prospectively included. Each patient underwent both STD-CT and ULD-CT acquisitions. ULD-CT images were reconstructed using two DLR levels (Smooth/Smoother). Dosimetric indicators, objective image quality, subjective image quality, and lesion detection were compared. Agreement between protocols and readers was assessed using Gwet's AC1 or AC2 coefficients. RESULTS:ULD-CT significantly reduced radiation exposure, with a mean CTDIvol reduction of -71.5% and dose-length product reduction of -71.5% (P < 0.05). Minor but statistically significant differences in HU values were observed between STD-CT and ULD-CT across most tissues. For all organs or tissues, image noise was significantly higher with ULD-CT-Smooth than with STD-CT (P < 0.001), and with ULD-CT-Smoother than with STD-CT, except for dorsal vertebra (P = 0.39) and trachea (P = 0.26). For all organs or tissues, image noise was significantly lower with the Smoother DLR level than with Smooth DLR level (P < 0.001). Agreement between STD-CT and ULD-CT regarding lesion detection was almost perfect for thoracic, abdominal, and bone lesions. Detection of infracentimetric hepatic was lower with ULD-CT, whereas detection of larger lesions (≥ 10 mm) remained similar. Subjective image quality was lower with ULD-CT, with moderate inter-reader agreement, and lower diagnostic confidence than with STD-CT. One of the two readers considered that 19%-24% of ULD-CT examinations were uninterpretable. CONCLUSION:ULD-CT with DLR offers substantial radiation dose reduction but resulted in poorer image quality and lower detection of small low-contrast abdominal lesions compared with STD-CT. Although lesion detection remained equivalent for thoracic and skeletal lesions, the high proportion of suboptimal or uninterpretable examinations may limit routine use of ULD protocols in cancer follow-up.
PURPOSE:The purpose of this study was to evaluate the association between systemic low bone mineral density (BMD) and subchondral insufficiency fracture (SIF) of the knee in women, and to explore whether this association is modified by radial meniscal tears. MATERIALS AND METHODS:In this case-control study, women with and without MRI-confirmed SIF who had available dual-energy X-ray absorptiometry T-score measurements were included. Systemic BMD was categorized using T-scores. Multivariable logistic regression models with BMD as the exposure and SIF as the outcome, adjusting for age and body mass index were fitted. An exploratory stratified analysis to assess potential effect modification by meniscal radial tear status was also conducted. RESULTS:A total of 121 women with SIF (mean age, 69.1 ± 7.5 [standard deviation] years) and 124 controls (70.4 ± 8.3 [standard deviation] years) were analyzed. After adjustment, osteoporosis was associated with higher odds of SIF (odds ratio [OR], 2.29; 95% confidence interval [CI]: 1.03-5.09), whereas osteopenia (OR, 1.33; 95% CI: 0.69-2.55) showed no significant association. In exploratory stratified analysis to test for effect modification, there were no significant interactions between low BMD and radial root tears (P-interaction = 0.178). However, small strata likely limited the power to detect a significant effect modification, as evidenced by overlapping wide 95% CIs. CONCLUSION:Osteoporosis is associated with higher odds of SIF of the knee in women, while osteopenia is not.
PURPOSE:The purpose of this study was to evaluate the relationship between subchondral insufficiency fracture (SIF) of the knee and radial meniscal tears on magnetic resonance imaging (MRI) and to examine within the medial compartment the potential mediating role of meniscal extrusion in this relationship. MATERIALS AND METHODS:A retrospective matched case-control study of knee MRI examinations obtained from November 2021 to November 2024 was performed. MRIs were reviewed for SIF, meniscal tear morphology, and meniscal extrusion grade. Associations between radial tears and SIF (overall and medial compartment) were evaluated using conditional logistic regression adjusted for age, sex, and body mass index. Medial-compartment mediation was examined using a natural effects model with medial meniscal extrusion as the mediator. RESULTS:The cohort included 343 patients with SIF (65.4 ± 10.1 [standard deviation] years; 226 women) and 343 patients without SIF (66.4 ± 10.0 [standard deviation] years; 224 women). Compared with knees without radial tears, odds of SIF were higher in the presence of radial root tears (odds ratio [OR], 7.62; 95% confidence interval [CI]: 4.40-13.21) and radial non-root tears (OR, 5.26; 95% CI: 2.48-11.15), with similar findings in the medial compartment. In mediation analysis, medial radial root tears showed an indirect association with medial SIF through medial meniscal extrusion (OR, 1.46; 95% CI: 1.16-1.84), accounting for 16.6% of the total effect. CONCLUSION:Radial root and non-root tears are strongly associated with SIF on MRI, particularly in the medial compartment. Meniscal extrusion explained a small proportion of this association, suggesting that additional biomechanical pathways are likely in play.
