Computerized image analysis: estimation of breast density on mammograms

An automated image analysis tool is being developed for the estimation of mammographic breast density. This tool may be useful for risk estimation or for monitoring breast density change in prevention or intervention programs. In this preliminary study, a data set of 4-view mammograms from 65 patients was used to evaluate our approach. Breast density analysis was performed on the digitized mammograms in three stages. First, the breast region was segmented from the surrounding background by an automated breast boundary-tracking algorithm. Second, an adaptive dynamic range compression technique was applied to the breast image to reduce the range of the gray level distribution in the low frequency background and to enhance the differences in the characteristic features of the gray level histogram for breasts of different densities. Third, rule-based classification was used to classify the breast images into four classes according to the characteristic features of their gray level histogram. For each image, a gray level threshold was automatically determined to segment the dense tissue from the breast region. The area of segmented dense tissue as a percentage of the breast area was then estimated. To evaluate the performance of the algorithm, the computer segmentation results were compared to manual segmentation with interactive thresholding by five radiologists. A "true" percent dense area for each mammogram was obtained by averaging the manually segmented areas of the radiologists. We found that the histograms of 6% (8 CC and 8 MLO views) of the breast regions were misclassified by the computer, resulting in poor segmentation of the dense region. For the images with correct classification, the correlation between the computer-estimated percent dense area and the "truth" was 0.94 and 0.91, respectively, for CC and MLO views, with a mean bias of less than 2%. The mean biases of the five radiologists' visual estimates for the same images ranged from 0.1% to 11%. The results demonstrate the feasibility of estimating mammographic breast density using computer vision techniques and its potential to improve the accuracy and reproducibility of breast density estimation in comparison with the subjective visual assessment by radiologists.     

Is mammography useful in screening for local recurrences in patients with TRAM flap breast reconstruction after mastectomy for multifocal DCIS?

Background: Skin-sparing mastectomy with immediate transverse rectus abdominis musculocutaneous (TRAM) flap reconstruction is being used more often for the treatment of breast cancer. Mammography is not used routinely to evaluate TRAM flaps in women who have undergone mastectomy. We have identified the potential value of its use in selected patients. Methods and Results: We report on four women who manifested local recurrences in TRAM flaps after initial treatment for ductal carcinoma in situ (DCIS) or DCIS with microinvasion undergoing skin-sparing mastectomy and immediate reconstruction. All four patients presented with extensive, high-grade, multifocal DCIS that precluded breast conservation. Three of four mastectomy specimens demonstrated tumor close to the surgical margin. Three of the four recurrences were detected by physical examination; the remaining local recurrence was documented by screening mammography. The recurrences had features suggestive of malignancy on mammography. Conclusion: We conclude that all patients undergoing mastectomy and TRAM reconstruction for extensive, multifocal DCIS should undergo regular routine mammography of the reconstructed breast. Our experience with this subgroup of patients raises concern about the value of skin-sparing mastectomy with immediate reconstruction for therapy. Adjuvant radiation therapy should be recommended for those patients with negative but close surgical margins.     

Breast masses: computer-aided diagnosis with serial mammograms

PURPOSE: To retrospectively evaluate effects of computer-aided diagnosis (CAD) involving an interval change classifier (which uses interval change information extracted from prior and current mammograms and estimates a malignancy rating) on radiologists' accuracy in characterizing masses on two-view serial mammograms as malignant or benign. MATERIALS AND METHODS: The data collection protocol had institutional review board approval. Patient informed consent was waived for this HIPAA-compliant retrospective study. Ninety temporal pairs of two-view serial mammograms (depicting 47 malignant and 43 benign biopsy-proved masses) were obtained from 68 patient files and were digitized. Biopsy was the reference standard. Eight Mammography Quality Standards Act of 1992-accredited radiologists and two breast imaging fellows assessed digitized two-view temporal pairs (in preselected regions of interest only) by estimating likelihood of malignancy and Breast Imaging Reporting and Data System (BI-RADS) category without and with CAD. Observers' rating data were analyzed with Dorfman-Berbaum-Metz (DBM) multireader multicase method. Statistical significance of differences was estimated with the DBM method and Student two-tailed paired t test. RESULTS: Average area under the receiver operating characteristic curve for likelihood of malignancy across the 10 observers was 0.83 (range, 0.74-0.88) without CAD and improved to 0.87 (range, 0.80-0.92) with CAD (P < .05). The average partial area index above a sensitivity of 0.90 for likelihood of malignancy was 0.35 (range, 0.13-0.54) without CAD and 0.49 (range, 0.18-0.73) with CAD--a nonsignificant improvement (P = .11). For BI-RADS assessment, it was estimated that with CAD, six radiologists would correctly recommend additional biopsies for malignant masses (range, 4.3%-10.6%) and five would correctly recommend reduction of biopsy (ie, fewer biopsies) for benign masses (range, 2.3%-9.3%). However, five radiologists would incorrectly recommend additional biopsy for benign masses (range, 2.3%-14.0%), and one would incorrectly recommend reduction of biopsy (4.3%). CONCLUSION: CAD involving interval change analysis of preselected regions of interest can significantly improve radiologists' accuracy in classifying masses on digitized screen-film mammograms as malignant or benign.     

Evaluation of traumatic groin arteriovenous fistulas with duplex Doppler sonography

Femoral arteriovenous fistula is a rare complication of percutaneous transfemoral catheterization. We report the duplex Doppler findings of three such cases. Continuous positive diastolic arterial flow, as well as an abnormal venous flow pattern, was observed in all cases. When present, these Doppler spectral changes support the diagnosis of arteriovenous fistula.     

Assessment of mammographic breast density after sleeve gastrectomy

Background

Mammographic breast density (BD) is an independent risk factor for breast cancer. The effects of bariatric surgery on BD are unknown.

Extent of Lumpectomy for Breast Cancer After Diagnosis by Stereotactic Core Versus Wire Localization Biopsy

Background: Stereotactic core biopsy of mammographically defined breast abnormalities is an alternative to wire localization biopsy. The purpose of this study was to evaluate the extent of lumpectomy in patients diagnosed by stereotactic core versus wire localization biopsy.Methods: A total of 67 consecutive patients diagnosed with invasive cancers or ductal carcinoma in situ (DCIS) were retrospectively reviewed. Thirty-four were diagnosed by core biopsy and the remaining 33 by wire localization biopsy.Results: Approximately 65% of patients subsequently had breast-conserving surgical therapy. Seventy-nine percent of patients undergoing wire localization biopsies had positive surgical margins. Achievement of negative surgical margins for lumpectomies performed after wire localization or stereotactic core biopsies was 100% and 89%, respectively, which was not significantly different. However, the total volume of breast tissue removed for breast conservation in patients undergoing lumpectomy after wire localization versus core biopsies was 183 cm³ and 104 cm³, respectively, which was significantly different (P = .003).Conclusions: Diagnosis by stereotactic core biopsies resulted in less tissue removal to achieve margin-negative lumpectomies for breast conservation. Stereotactic core biopsy is the method of choice for biopsying nonpalpable, suspicious breast lesions.