Computer-aided detection (CAD) for breast MRI: evaluation of efficacy at 3.0 T.

OBJECTIVE: The purpose of the study was to evaluate the accuracy of 3.0-T breast MRI interpretation using manual and fully automated kinetic analyses. MATERIAL AND METHODS: Manual MRI interpretation was done on an Advantage Workstation. Retrospectively, all examinations were processed with a computer-aided detection (CAD) system. CAD data sets were interpreted by two experienced breast radiologists and two residents. For each lesion automated analysis of enhancement kinetics was evaluated at 50% and 100% thresholds. Forty-nine malignant and 22 benign lesions were evaluated. RESULTS: Using threshold enhancement alone, the sensitivity and specificity of CAD were 97.9% and 86.4%, respectively, for the 50% threshold, and 97.9% and 90%, respectively, for the 100% threshold. Manual interpretation by two breast radiologists showed a sensitivity of 84.6% and a specificity of 68.8%. For the same two radiologists the mean sensitivity and specificity for CAD-based interpretation was 90.4% (not significant) and 81.3% (significant at p < 0.05), respectively. With one-way ANOVA no significant differences were found between the two breast radiologists and the two residents together, or between any two readers separately. CONCLUSION: CAD-based analysis improved the specificity compared with manual analysis of enhancement. Automated analysis at 50% and 100% thresholds showed a high sensitivity and specificity for readers with varying levels of experience.

Feasibility of MRI-guided large-core-needle biopsy of suspiscious breast lesions at 3 T.

The feasibility of large-core-needle magnetic resonance imaging (MRI)-guided breast biopsy at 3 T was assessed. Thirty-one suspicious breast lesions shown only by MRI were detected in 30 patients. Biopsy procedures were performed in a closed-bore 3-T clinical MR system on a dedicated phased-array breast coil with a commercially available add-on stereotactic biopsy device. Tissue sampling was technically successful in 29/31 (94%) lesions. Median lesion size (n = 29) was 9 mm. Histopathological analysis showed 19 benign lesions (66%) and one inconclusive biopsy result (3%). At follow-up of these lesions, 15 lesions showed no malignancy, no information was available in three patients and two lesions turned out to be malignant (one lesion at surgical excision 1 month after biopsy and one lesion at a second biopsy because of a more malignant enhancement curve at 12-months follow-up MRI). Nine biopsy results showed a malignant lesion (31%) which were all surgically removed. No complications occurred. MRI-guided biopsy at 3 T is a safe and effective method for breast biopsy in lesions that are occult on mammography and ultrasound. Follow-up MRI at 6 months after the biopsy should be performed in case of a benign biopsy result.

Radiofrequency-assisted intact specimen biopsy of breast tumors: critical evaluation according to the IDEAL recommendations.

Radiofrequency-assisted intact specimen biopsy (RFIB) has been introduced for percutaneous biopsy or removal of breast tumors. Using radiofrequency cutting, the system enables the radiologist to obtain an intact sample of the target lesion. According to the IDEAL recommendations, we performed a critical evaluation of our initial experience with RFIB. Between June and November 2010, radiography-guided RFIB was performed in 19 female patients. All patients presented with suspicious microcalcifications (BI-RADS III-V) on mammography. Biopsy specimen integrity, thermal damage and histologic diagnosis were assessed by an expert breast pathologist. Data on technical success, diagnostic and therapeutic accuracy and periprocedural complications were collected and analyzed. The median age of the patients was 59 years. Median lesion diameter on mammography was 8 mm (range 2-76 mm). The procedure was successful in 16/19 (84%) patients and unsuccessful in 3/19 (16%) patients (2 non-representative samples, 1 sample with extensive thermal damage). Histologic analysis of the RFIB specimen revealed 12/19 (63%) benign lesions and 7/19 (37%) malignancies (4 ductal carcinoma in situ (DCIS) lesions and 3 invasive ductal carcinomas). In 1 patient, a DCIS lesion was completely removed with RFIB. Overall, 3 periprocedural complications occurred (1 wound leakage, 1 arterial hemorrhage and 1 infection requiring oral antibiotics). Tissue sampling of suspicious breast lesions can be performed successfully with RFIB. In 1 patient DCIS was radically excised with RFIB, which illustrates its potential as a minimally invasive therapeutic procedure for removal of small breast tumors. This is an interesting focus for further research when larger probe sizes become available.