Can breast MRI computer-aided detection (CAD) improve radiologist accuracy for lesions detected at MRI screening and recommended for biopsy in a high-risk population?

AIM: To evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) computer-aided detection (CAD) for breast MRI screen-detected lesions recommended for biopsy in a high-risk population. MATERIAL AND METHODS: Fifty-six consecutive Breast Imaging Reporting and Data System (BI-RADS) 3-5 lesions with histopathological correlation [nine invasive cancers, 13 ductal carcinoma in situ (DCIS) and 34 benign] were retrospectively evaluated using a breast MRI CAD prototype (CAD-Gaea). CAD evaluation was performed separately and in consensus by two radiologists specializing in breast imaging, blinded to the histopathology. Thresholds of 50, 80, and 100% and delayed enhancement were independently assessed with CAD. Lesions were rated as malignant or benign according to threshold and delayed enhancement only and in combination. Sensitivities, specificities, and negative predictive values (NPV) were determined for CAD assessments versus pathology. Initial MRI BI-RADS interpretation without CAD versus CAD assessments were compared using paired binary diagnostic tests. RESULTS: Threshold levels for lesion enhancement were: 50% to include all malignant (and all benign) lesions; and 100% for all invasive cancer and high-grade DCIS. Combined use of threshold and enhancement patterns for CAD assessment was best (73% sensitivity, 56% specificity and 76% NPV for all cancer). Sensitivities and NPV were better for invasive cancer (100%/100%) than for all malignancies (54%/76%). Radiologists' MRI interpretation was more sensitive than CAD (p=0.05), but less specific (p=0.001) for cancer detection. CONCLUSION: The breast MRI CAD system used could not improve the radiologists' accuracy for distinguishing all malignant from benign lesions, due to the poor sensitivity for DCIS detection.

Fat halo sign in the bowel wall of patients with Crohn's disease.

AIM: To evaluate the prevalence and localization of the deposition of submucosal fat, the "fat halo sign" (FHS), using computed tomography (CT) in the bowel wall of patients with Crohn's Disease, and to assess its relation to the duration of the disease. MATERIALS AND METHODS: The abdominal CT examinations of 100 consecutive patients were reviewed for the presence of the FHS in the bowel wall. A measurement of less than -10HU was regarded as indicative of fat. CT findings were correlated with the duration of the disease and statistically tested by simple regression analysis. The patients were divided into two groups: group A included 26 patients with a disease duration of less than 1 year and group B included 73 with a longer disease duration. In one patient disease duration was unknown. To test the relationship between disease duration and FHS the cumulative number of FHS positive and negative patients was plotted against disease duration. RESULTS: The FHS was present in 17 of the 100 patients in 20 bowel segments, mainly in the ileum (10) and the ascending colon (8). The FHS was present in 3.8% in group A and in 21.9% in group B (p<0.0375). CONCLUSION: The FHS was present in 17% of patients with CD. Its location was mainly in the terminal ileum and ascending colon, typical sites of the disease. Its prevalence was significantly duration dependent.