In the digital era, architectural distortion remains a challenging radiological task.

AIM: To compare readers' performance in detecting architectural distortion (AD) compared with other breast cancer types using digital mammography. MATERIALS AND METHODS: Forty-one experienced breast screen readers (20 US and 21 Australian) were asked to read a single test set of 30 digitally acquired mammographic cases. Twenty cases had abnormal findings (10 with AD, 10 non-AD) and 10 cases were normal. Each reader was asked to locate and rate any abnormalities. Lesion and case-based performance was assessed. For each collection of readers (US; Australian; combined), jackknife free-response receiver operating characteristic (JAFROC), figure of merit (FOM), and inferred receiver operating characteristic (ROC), area under curve (Az) were calculated using JAFROC v.4.1 software. Readers' sensitivity, location sensitivity, JAFROC, FOM, ROC, Az scores were compared between cases groups using Wilcoxon's signed ranked test statistics. RESULTS: For lesion-based analysis, significantly lower location sensitivity (p=0.001) was shown on AD cases compared with non-AD cases for all reader collections. The case-based analysis demonstrated significantly lower ROC Az values (p=0.02) for the first collection of readers, and lower sensitivity for the second collection of readers (p=0.04) and all-readers collection (p=0.008), for AD compared with non-AD cases. CONCLUSIONS: The current work demonstrates that AD remains a challenging task for readers, even in the digital era.

Ghost imaging in MRI.

Needle biopsies and other interventions done under MR Fluoroscopy sometimes do not show the target well, either because the rapid sequence does not have adequate contrast or because a contrast agent may have washed out of the target. In these cases, an image that shows the target can be saved and scaled to match the spatial parameters of the fluoroscopic sequence, and used as a virtual or ghost field upon which the fluoroscopic images are superimposed, thus providing a view of the target, useful for needle pre-localization and for monitoring its progress as it is inserted.

Calcifications of lobular carcinoma in situ of the breast: radiologic-pathologic correlation.

OBJECTIVE: Because lobular carcinoma in situ is thought to be an incidental finding at breast pathology, the finding of lobular carcinoma in situ at core biopsy poses a diagnostic dilemma of radiologic-pathologic concordance. The purpose of this article is to describe the radiologic-pathologic correlation of calcifications associated with lobular carcinoma in situ of the breast. MATERIALS AND METHODS: Between July 1999 and July 2000, seven excisional biopsies resulted in findings of lobular carcinoma in situ of mammographic calcifications. The radiographic features of the calcifications were characterized by the Breast Imaging Reporting and Data System lexicon, and pathologic features were reviewed. RESULTS: Two forms of lobular carcinoma in situ were associated with calcifications: the classic form with small, uniform cells, and the pleomorphic form with larger cells frequently associated with central necrosis. On mammography, all calcifications were clustered, punctate, high density, and smaller than or equal to 0.5 mm, although mammographically visible calcifications found in the pleomorphic type tended to be larger and more dense. Additionally, infiltrating lobular carcinoma was found after surgical excision in two (40%) of five patients with pleomorphic lobular carcinoma in situ. CONCLUSION: Calcifications can be associated with lobular carcinoma in situ and therefore concordant at stereotactic core biopsy. The classic form may be incidental and clinically innocuous. The pleomorphic form is morphologically similar to ductal carcinoma in situ and may have a greater tendency for invasion.

Ghost imaging for targeting breast masses with MR imaging: a phantom study.

RATIONALE AND OBJECTIVES: The purpose of this study was to test the accuracy of ghost magnetic resonance (MR) imaging for guiding core biopsies of simulated breast masses in a tissue phantom. MATERIALS AND METHODS: A tissue MR phantom implanted with 20 grapes as targets was placed into an interventional breast MR coil. The locations of the centers of the targets were determined, recorded, and saved as ghost images. A nonmagnetic phantom needle was constructed to avoid imprecision secondary to magnetic field inhomogeneity and was used to determine the three-dimensional location of the needle tip in the center of each grape on the ghost image. Once the positions were determined, the true needle was placed and biopsy specimens were taken. The needle was inspected for the presence of pulp after each pass. Each grape was inspected to determine the location of the needle track in relation to the center of the grape. The duration of the procedure was recorded. RESULTS: All grapes were hit by the biopsy needle, as demonstrated either by pulp within the needle or by a needle track within the grape. Seventeen of the 20 grapes (85%) were hit centrally. Three were sampled eccentrically, up to 5-6 mm from the center. Each biopsy took approximately 1 hour. CONCLUSION: These results suggest that ghost imaging may be ideal for needle guidance in core biopsy or preoperative localization, as it extends the period of visibility after a bolus injection of contrast material. Additionally, using a phantom needle for localization appears to overcome imprecision due to magnetic field inhomogeneity of the needle.

Sonography of palpable breast cancer.

PURPOSE: Because of the increasing use of sonography to rule out cancer in women with palpable breast abnormalities, this study was performed to determine the rate of sonographically occult malignancy in this clinical setting. METHODS: Women who were recommended for biopsy based on mammographic and/or clinical findings underwent breast sonography. This study retrospectively analyzed the subset of patients with palpable malignant lesions. Lesions were classified as visible or occult on mammography and sonography. Patients without a tissue diagnosis of tumor were excluded. RESULTS: Of 1,346 masses that underwent biopsy or aspiration, 616 lesions were palpable, and of these, 293 were malignant. Sonography detected all 293 palpable malignant lesions (95% confidence interval for sensitivity, 99-100%). Eighteen lesions were mammographically occult. The median lesion size as determined by sonography was 1.8 cm; for the lesions that were mammographically occult, the median size was 1.6 cm. The most common histopathologic diagnosis for both groups of lesions was infiltrating ductal carcinoma. CONCLUSIONS: All palpable malignant breast lesions were visible by sonography in patients in whom a biopsy was recommended. However, we caution that until the false-negative rate of sonography for equivocal palpable abnormalities is determined prospectively, sonography cannot be accurately applied to rule out malignancy in this setting.

From the RSNA refresher courses. Freehand interventional sonography in the breast: basic principles and clinical applications.

The skills needed to perform ultrasonographic (US)-guided interventional procedures in the breast can be learned by practicing the key maneuvers on a tissue phantom. Use of a tissue phantom rather than a synthetic phantom provides the tactile feedback from transducer movement against tissue and from needle insertion into tissue, which more closely simulates the performance of the procedure in a real breast. There are three key transducer motions--sweeping, rocking, and rotating--that are used to achieve three important goals in US-guided procedures: finding the needle, maximally visualizing the needle, and correctly aligning the needle shaft and ultrasound beam. For each transducer maneuver, there is a corollary needle motion that can be used to achieve the same goal. Either the transducer or the needle should be moved during a procedure, not both simultaneously. Longitudinal alignment of the needle shaft with the ultrasound beam is best achieved with the perpendicular approach. The perpendicular approach is preferred because it allows superior needle visualization, orientation parallel to the chest wall, and location of the needle shaft at the focal zone. With use of a tissue phantom, the radiologist-in-training can practice the key procedures and tailor them to his or her individual preferences.

Regression of breast cancer in four patients treated with tamoxifen: mammographic features.

OBJECTIVE: The purpose of this article is to illustrate the regression of breast cancer as seen on mammograms of women treated with tamoxifen. SUBJECTS AND METHODS: Four elderly patients 72-88 years old were diagnosed with breast cancer on the basis of mammographic features. No surgery was performed because of multiple medical problems. Tamoxifen was initiated and the patients were closely monitored with physical examination and mammography for a minimum of 2 years. RESULTS: In all cases, the features of malignancy seen on mammograms regressed. These results were documented by a decrease in the number of calcifications and in the size of spiculated masses. CONCLUSION: These results suggest that tamoxifen, or one of its metabolites, may alter the biochemical nature of breast cancer.

Breast biopsy with needle localization: accuracy of specimen x-ray and management of missed lesions.

BACKGROUND: One of the more frustrating complications after breast biopsy with needle localization is a missed lesion. To reduce the number of missed lesions, radiographs of the surgical specimen are usually obtained. In this study we determined the accuracy of specimen x-ray, the incidence of missed lesions, and the management of patients with this complication. METHODS: The result of specimen x-ray was compared with that of a postoperative mammogram in 192 patients who underwent breast biopsy with needle localization. The incidence of missed lesions was also determined from postoperative mammogram, and the management of patients with this complication was analyzed. RESULTS: The incidence of false-positive specimen x-ray was 7.8% and that of false-negative 55%. The sensitivity, specificity, and accuracy of specimen x-ray were 96%, 28%, and 89%, respectively. The incidence of missed lesions was 3.2% and of incompletely excised lesions 6.4%. Eighteen of 24 patients with a missed or incompletely excised lesion were treated expectantly because postoperative mammogram showed the lesion to be stable. None of these patients has required a subsequent biopsy. CONCLUSIONS: Specimen x-ray can be false positive or false negative. An important implication of this finding is that a postoperative mammography should always be performed after biopsy with needle localization, regardless of the result of the specimen x-ray, to make certain the lesion has not been missed.