Adenoid cystic carcinoma of the breast.

OBJECTIVE: The purpose of our study was to describe the imaging findings in adenoid cystic carcinoma (ACC) of the breast, with pathologic and clinical correlation. MATERIALS AND METHODS: We retrospectively searched our surgical database from January 1994 through December 2008 for cases of pathologically proven ACC of the breast. Of approximately 15,000 breast biopsies, 11,250 were malignant. Eleven cases of ACC (0.1% of all malignancies), all with imaging available for review, were included in the study. RESULTS: Mammographically (n = 10), tumors appeared as developing asymmetric densities or irregular masses. Sonographically (n = 9), they appeared as irregular, heterogeneous, or hypoechoic masses with minimal vascularity on color Doppler imaging. MRI (n = 5)--because of better soft-tissue contrast and dedicated, multiplanar breast sequences--helped show the extent of the tumor, particularly if dense breast tissue obscured the mass on CT. Two cases with subtle sonographic findings were better delineated on MRI because of tumor enhancement. The solid variant showed increased signal intensity on T2-weighted imaging. ACC showed variable enhancement kinetics ranging from persistent enhancement to washout kinetics in the larger lesions. On molecular breast imaging (n = 1), the tumors showed avid uptake of radiotracer but did not always show activity on PET (n = 1). CT (n = 2) showed areas of rapid, nodular enhancement. CONCLUSION: Recognition of ACC is important to avoid delay in diagnosis because this tumor has a good prognosis with rare metastases to axillary lymph nodes. Axillary nodal sampling by fine-needle aspiration or core biopsy is rarely indicated.

The effects of gray scale image processing on digital mammography interpretation performance.

RATIONALE AND OBJECTIVES: To determine the effects of three image-processing algorithms on diagnostic accuracy of digital mammography in comparison with conventional screen-film mammography. MATERIALS AND METHODS: A total of 201 cases consisting of nonprocessed soft copy versions of the digital mammograms acquired from GE, Fischer, and Trex digital mammography systems (1997-1999) and conventional screen-film mammograms of the same patients were interpreted by nine radiologists. The raw digital data were processed with each of three different image-processing algorithms creating three presentations-manufacturer's default (applied and laser printed to film by each of the manufacturers), MUSICA, and PLAHE-were presented in soft copy display. There were three radiologists per presentation. RESULTS: Area under the receiver operating characteristic curve for GE digital mass cases was worse than screen-film for all digital presentations. The area under the receiver operating characteristic for Trex digital mass cases was better, but only with images processed with the manufacturer's default algorithm. Sensitivity for GE digital mass cases was worse than screen film for all digital presentations. Specificity for Fischer digital calcifications cases was worse than screen film for images processed in default and PLAHE algorithms. Specificity for Trex digital calcifications cases was worse than screen film for images processed with MUSICA. CONCLUSION: Specific image-processing algorithms may be necessary for optimal presentation for interpretation based on machine and lesion type.

Multidetector helical computed tomography of the liver: comparison of hepatic enhancement using two different contrast media strategies.

RATIONALE AND OBJECTIVES: The purpose of this study was to compare hepatic enhancement characteristics using two different contrast media injection protocols with multidetector helical computed tomography. MATERIALS AND METHODS: Twenty-three patients with known or suspected liver lesions scheduled to undergo biphasic hepatic multidetector helical computed tomography were randomized into one of two groups: (1) 150 mL of iopamidol (300 mgI/mL) at 5 mL/second, or (2) 100 mL of iopamidol (370 mgI/mL) at 4 mL/second. Unenhanced images were acquired initially, followed by both hepatic arterial phase (scan delay, 33 seconds) and portal venous phase (PVP; scan delay, 65 seconds) imaging. Three abdominal radiologists independently graded the images on a scale from 1-5 for enhancement and overall scan quality. Time-attenuation curves were generated from operator-defined region-of-interest measurements of liver parenchyma and aorta. RESULTS: Qualitatively, the three reviewers found no significant difference between the two study groups in terms of overall scan quality (P = .23) or aortic enhancement (hepatic arterial phase, P = .9; PVP, P = .24). However, liver enhancement during the PVP was considered to be less in the Isovue 370 group (P = .04). Quantitatively, during the hepatic arterial phase, there was no statistically significant difference between the two injection protocols comparing either aortic or hepatic parenchymal enhancement (P = .62 and .80, respectively). During the PVP, these differences were statistically significant, with both aortic and hepatic parenchymal enhancement lower in the Isovue 370 group (P < .01 and P = .04, respectively). CONCLUSION: It is important to consider the amount of iodine injected per second and the duration of the injection when setting up protocols to achieve target organ enhancement. 100 mL of iopamidol 370 at 4 mL/second can be used to obtain images of the liver with good diagnostic quality compared to more conventional protocols using 150 mL of iopamidol 300 at 5 mL/second. However, the degree of liver parenchymal enhancement during the PVP using the latter injection scheme is lower, which in turn could potentially reduce hepatic lesion conspicuity.

Comparison of recall and cancer detection rates for immediate versus batch interpretation of screening mammograms.

PURPOSE: To retrospectively compare recall and cancer detection rates between immediate and subsequent batch methods for interpretation of screening mammograms. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived. Retrospective analysis was performed for 8698 screening mammograms obtained between January 1 and October 31, 2001, which were interpreted either immediately (n = 4113) or subsequently with batch method (n = 4585). Data were collected from data reporting system and patient billing records. Patients with high risk factors were excluded; 3441 patients were in the immediate group, and 3932 were in the batch group. The two groups were compared with respect to age, breast density, and availability of comparison films with Wilcoxon rank sum test. Recall rates and cancer detection rates for each group were determined and compared with Pearson chi(2) test; false-negative rates were compared with Fischer exact test. RESULTS: A significant difference (P < .001) was noted in recall rates between immediate (18%) and batch (14%) groups; however, no significant difference (P = .7) was noted in cancer detection rates (immediate, 0.5%; batch, 0.4%). Mean age of patients was 56.8 years (age range, 21-96 years) in the immediate group and 56.2 years (age range 24-98 years) in the batch group (P = .02). Comparison of breast densities between groups indicates no statistically significant difference (P = .4). The batch group had significantly fewer comparison mammograms (3106 [79%]) available than the immediate group (2856 [83%]) (P < .001). There was no significant difference in false-negative rates between the immediate group (0.1%) and the batch group (0.1%) (P > .99). CONCLUSION: Immediate interpretation of screening mammograms resulted in a statistically significant increase in recalls and additional clinical work-ups of perceived abnormalities; however, no significant difference in cancer detection rate was detected between groups.

Abdominal aortic aneurysms at multi-detector row helical CT: optimization with interactive determination of scanning delay and contrast medium dose.

PURPOSE: To prospectively evaluate a technique for optimizing aortoiliac enhancement at multi-detector row helical computed tomography (CT) with both the scanning delay and contrast medium dose determined by using an interactive method. MATERIALS AND METHODS: Forty-five patients with abdominal aortic aneurysm were randomized to undergo multi-detector row helical CT with either an interactive protocol (n = 23) or a standard protocol (n = 22). Scanning delays in all patients were determined with automated triggering. Patients in the standard protocol group received 150 mL of contrast medium intravenously at 4 mL/sec. The same injection rate was used for the interactive protocol group, but the dose was reduced with discontinuation of injection at start of scanning. Quantities of contrast medium used and contrast-enhanced aortic attenuation achieved were compared. Aortoiliac enhancement was evaluated qualitatively by using a five-point scale (1 = poor, 5 = excellent). Quantitative and qualitative data were analyzed with the two-tailed t test and Wilcoxon rank sum test, respectively, to determine significance of differences (P <.05). RESULTS: Data from six patients were excluded because of technical errors. Data were analyzed from 20 patients in the interactive protocol group and 19 in the standard protocol group. Mean contrast medium volume was 107 mL +/- 20 (standard deviation) in the interactive protocol group and 148 mL +/- 3 in the standard protocol group (P <.001). Mean contrast-enhanced attenuation at initial, peak, and final measurements was 257 HU +/- 38, 285 HU +/- 46, and 269 HU +/- 54, respectively, for the interactive protocol group, and 261 HU +/- 65, 288 HU +/- 66, and 269 HU +/- 61 for the standard protocol group (P >.05). Mean qualitative enhancement scores for interactive and standard protocol groups were 4.47 and 4.44, respectively (P =.47). CONCLUSION: The interactive method is a simple, efficient, and reproducible way to optimize aortoiliac enhancement while reducing contrast medium dose.

Computer-aided detection (CAD) in screening mammography: sensitivity of commercial CAD systems for detecting architectural distortion.

OBJECTIVE: Computer-aided detection (CAD) algorithms have successfully revealed breast masses and microcalcifications on screening mammography. The purpose of our study was to evaluate the sensitivity of commercially available CAD systems for revealing architectural distortion, the third most common appearance of breast cancer. MATERIALS AND METHODS: Two commercially available CAD systems were used to evaluate screening mammograms obtained in 43 patients with 45 mammographically detected regions of architectural distortion. For each CAD system, we determined the sensitivity for revealing architectural distortion on at least one image of the two-view mammographic examination (case sensitivity) and for each individual mammogram (image sensitivity). Surgical biopsy results were available for each case of architectural distortion. RESULTS: Architectural distortion was deemed present and actionable by a panel of expert breast imagers in 80 views of the 45 cases. One CAD system detected distortion in 22 of 45 cases of distortion (case sensitivity, 49%) and in 30 of 80 mammograms (image sensitivity, 38%); it displayed 0.7 false-positive marks per image. Another CAD system identified distortion in 15 of 45 cases (case sensitivity, 33%) and 17 of 80 mammograms (image sensitivity, 21%); it displayed 1.27 false-positive marks per image. Sensitivity for malignancy-caused distortion was similar to or lower than sensitivity for all causes of distortion. CONCLUSION: Fewer than one half of the cases of architectural distortion were detected by the two most widely available CAD systems used for interpretations of screening mammograms. Considerable improvement in the sensitivity of CAD systems is needed for detecting this type of lesion. Practicing breast imagers who use CAD systems should remain vigilant for architectural distortion.