Internal mammary lymph nodes as incidental findings at screening breast MRI.

OBJECTIVE: To evaluate the prevalence of internal mammary lymph nodes (IMLNs) on breast magnetic resonance imaging (MRI) in a screening population. MATERIALS AND METHODS: We retrospectively reviewed 92 consecutive screening breast MRI exams. Logistic regression was performed to ascertain the risk of IMLNs in cancer-free subjects and to determine whether the risk varies with age. RESULTS: IMLNs were present in 48.9% of patients. Mean node size was 4 mm (range, 3-10 mm). The prevalence of IMLNs was not related to age. No patients developed breast cancer after a mean follow-up of 3 years. CONCLUSION: Subcentimeter IMLNs are common incidental findings at screening breast MRI.

Repeatability of quantitative MRI measurements in normal breast tissue.

PURPOSE: To evaluate the variability and repeatability of repeated magnetic resonance imaging (MRI) measurements in normal breast tissues between and within subjects. METHODS: Eighteen normal premenopausal subjects underwent two contrast-enhanced MRI scans within 72 hours or during the same menstrual phase in two consecutive months. A subset of nine women also completed diffusion-weighted imaging (DWI). Fibroglandular tissue (FGT) density and FGT enhancement were measured on the contrast-enhanced MRI. Apparent diffusion coefficient (ADC) values were computed from DWI. Between- and within-subject coefficients of variation (bCV and wCV, respectively) were assessed. Repeatability of all measurements was assessed by the coefficient of repeatability (CR) and Bland-Altman plots. RESULTS: The bCV of FGT density and FGT enhancement at visit 1 and visit 2 ranged from 47% to 63%. The wCV was 13% for FGT density, 22% for FGT enhancement, and 11% for ADC. The CRs of FGT density and FGT enhancement were 0.15 and 0.19, respectively, and for ADC, it was 6.1 x 10(-4) mm(2)/s. CONCLUSIONS: We present an estimate of the variability and repeatability of MR measurements in normal breasts. These estimates provide the basis for understanding the normal variation of healthy breast tissue in MRI and establishing thresholds for agreement between measurements.

Agreement of mammographic measures of volumetric breast density to MRI.

BACKGROUND: Clinical scores of mammographic breast density are highly subjective. Automated technologies for mammography exist to quantify breast density objectively, but the technique that most accurately measures the quantity of breast fibroglandular tissue is not known. PURPOSE: To compare the agreement of three automated mammographic techniques for measuring volumetric breast density with a quantitative volumetric MRI-based technique in a screening population. MATERIALS AND METHODS: Women were selected from the UCSF Medical Center screening population that had received both a screening MRI and digital mammogram within one year of each other, had Breast Imaging Reporting and Data System (BI-RADS) assessments of normal or benign finding, and no history of breast cancer or surgery. Agreement was assessed of three mammographic techniques (Single-energy X-ray Absorptiometry [SXA], Quantra, and Volpara) with MRI for percent fibroglandular tissue volume, absolute fibroglandular tissue volume, and total breast volume. RESULTS: Among 99 women, the automated mammographic density techniques were correlated with MRI measures with R(2) values ranging from 0.40 (log fibroglandular volume) to 0.91 (total breast volume). Substantial agreement measured by kappa statistic was found between all percent fibroglandular tissue measures (0.72 to 0.63), but only moderate agreement for log fibroglandular volumes. The kappa statistics for all percent density measures were highest in the comparisons of the SXA and MRI results. The largest error source between MRI and the mammography techniques was found to be differences in measures of total breast volume. CONCLUSION: Automated volumetric fibroglandular tissue measures from screening digital mammograms were in substantial agreement with MRI and if associated with breast cancer could be used in clinical practice to enhance risk assessment and prevention.

Imaging late complications of cholecystectomy.

OBJECTIVE: To review the imaging findings in late complications of cholecystectomy. CONCLUSIONS: Late postcholecystectomy complications include papillary stenosis, choledocholithiasis, biliary stricture, remnant gallbladder, and dropped gallstones. Such complications can cause substantial morbidity, and knowledge of the imaging appearances can facilitate expeditious diagnosis and treatment.