Contrast-enhanced MR angiography and perfusion imaging of the hand.

OBJECTIVE: The goal of this investigation was to develop a technique for producing high-resolution gadolinium-enhanced MR images of the hand that show three-dimensional angiographic anatomy and permit measurement of distal soft-tissue perfusion. CONCLUSION: High-resolution MR angiograms of the hand, as well as qualitative perfusion information, can be produced using a rapid sequential gadolinium-enhanced three-dimensional gradient-echo technique.

Development, standardization, and testing of a lexicon for reporting contrast-enhanced breast magnetic resonance imaging studies.

The purpose of this study was to develop, standardize, and test reproducibility of a lexicon for reporting contrast-enhanced breast magnetic resonance imaging (MRI) examinations. To standardize breast MRI lesion description and reporting, seven radiologists with extensive breast MRI experience developed consensus on technical detail, clinical history, and terminology reporting to describe kinetic and architectural features of lesions detected on contrast-enhanced breast MR images. This lexicon adapted American College of Radiology Breast Imaging and Data Reporting System terminology for breast MRI reporting, including recommendations for reporting clinical history, technical parameters for breast MRI, descriptions for general breast composition, morphologic and kinetic characteristics of mass lesions or regions of abnormal enhancement, and overall impression and management recommendations. To test morphology reproducibility, seven radiologists assessed morphology characteristics of 85 contrast-enhanced breast MRI studies. Data from each independent reader were used to compute weighted and unweighted kappa (kappa) statistics for interobserver agreement among readers. The MR lexicon differentiates two lesion types, mass and non-mass-like enhancement based on morphology and geographical distribution, with descriptors of shape, margin, and internal enhancement. Lexicon testing showed substantial agreement for breast density (kappa = 0.63) and moderate agreement for lesion type (kappa = 0.57), mass margins (kappa = 0.55), and mass shape (kappa = 0.42). Agreement was fair for internal enhancement characteristics. Unweighted kappa statistics showed highest agreement for the terms dense in the breast composition category, mass in lesion type, spiculated and smooth in mass margins, irregular in mass shape, and both dark septations and rim enhancement for internal enhancement characteristics within a mass. The newly developed breast MR lexicon demonstrated moderate interobserver agreement. While breast density and lesion type appear reproducible, other terms require further refinement and testing to lead to a uniform standard language and reporting system for breast MRI. J. Magn. Reson. Imaging 2001;13:889-895.

Radiologic features of complications arising from dropped gallstones in laparoscopic cholecystectomy patients.

OBJECTIVE: Because laparoscopic cholecystectomy has become the accepted treatment for symptomatic cholelithiasis, radiologists frequently encounter patients who have had this surgery. Although the radiologic features of postoperative bile duct injury are well documented, the imaging features of less well-known complications remain poorly described. One such unusual complication is abscess formation caused by dropped gallstones. CONCLUSION: Although the incidence of dropped gallstones is an uncommon complication of laparoscopic cholecystectomy, it should be recognized as a potential source of both intraabdominal and intrathoracic abscess formation in any patient presenting months to years after undergoing laparoscopic cholecystectomy. These abscesses are not necessarily confined to the right upper quadrant.

Correlation of lesion appearance and histologic findings for the nodes of a breast MR imaging interpretation model.

An interpretation model for evaluating magnetic resonance (MR) images of the breast was constructed that allowed differentiation of benign from malignant palpable or mammographically visible abnormalities. Architectural features define each node of the model. Investigation was subsequently made of the histologic findings in individuals within each node and of the frequency with which each histologic finding manifested as a particular architectural feature to determine whether nodal location and specific histologic findings are mutually predictive. The strongest associations were found between fibrocystic change and smooth masses, fibroadenoma and lobulated masses with nonenhancing internal septations, invasive ductal carcinoma (with or without ductal carcinoma in situ [DCIS]) and enhancing irregular or spiculated masses, invasive tubular carcinoma or radial scar and spiculated masses, medullary or colloid carcinoma and enhancing lobulated masses, invasive lobular carcinoma and the absence of a focal mass, DCIS and ductal enhancement, and DCIS (with or without invasive ductal carcinoma) and regional enhancement. Nodal location and histologic findings proved to be mutually predictive within the model; that is, the nodal location of MR imaging features within the model can be used to predict histologic findings and vice versa.

Medial Segond-type fracture: cortical avulsion off the medial tibial plateau associated with tears of the posterior cruciate ligament and medial meniscus.

We describe an unusual cortical avulsion fracture off the medial tibial plateau of the knee associated with tears of the posterior cruciate ligament and the medical meniscus. This constellation of findings is the reverse of that seen with the Segond injury complex. We postulate that the plain film diagnosis of this fracture, like the Segond fracture, is a clue to the likely presence of associated ligamental and meniscal tears, and to the mechanism of injury.

MR imaging of the symptomatic ankle and foot.

MR imaging can play a key role in the evaluation of soft tissues and marrow space of the symptomatic muscle and foot. Diagnostic efficacy is optimized by tailoring the examination to a given problem. Techniques for MR imaging of the foot and ankle are reviewed, the clinical use of MR imaging for examining the structures of the foot and ankle is discussed, and strategies for the integration of MR imaging into the work-up of selected clinical problems are presented.

Fibroadenomas: MR imaging appearances with radiologic-histopathologic correlation.

PURPOSE: To identify histopathologic correlates for the varied magnetic resonance (MR) imaging appearances of fibroadenomas. MATERIALS AND METHODS: Twenty-three fibroadenomas in 21 patients (aged 23-66 years) examined with gadolinium-enhanced MR imaging were graded for signal intensity on T2-weighted images, contrast material enhancement, shape, and internal septations and were correlated with histopathologic findings. RESULTS: Fibroadenomas demonstrated high T2 signal intensity with enhancement (n = 11), low T2 signal intensity with enhancement (n = 3), or low T2 signal intensity without enhancement (n = 9). Low T2 signal intensity and lack of enhancement were associated with more sclerotic stroma and older patient age. Lesion shape was lobular, oval, or round in 19 of 23 fibroadenomas (83%). Internal septations were identified within nine of 14 enhancing fibroadenomas (64%) and appeared to correlate with collagenous bands at histopathologic analysis. CONCLUSION: Fibroadenomas demonstrate marked histopathologic variability. The resultant variability in the MR appearance limits the ability to distinguish between benign and malignant masses on the basis of signal intensity and enhancement alone. Lobulation and internal septation, which appear to reflect intrinsic growth patterns of fibroadenomas, may provide a more reliable basis for distinction.

Breast MR imaging: interpretation model.

PURPOSE: To develop an interpretation model based on architectural features of suspicious breast findings on magnetic resonance (MR) images. MATERIALS AND METHODS: One hundred ninety-two patients with mammographically visible or palpable findings underwent T1- and fat-saturated T2-weighted spin-echo and contrast agent-enhanced fat-saturated gradient-echo MR imaging. Patients underwent subsequent excisional biopsy for histopathologic confirmation. An interpretation model was constructed by using 98 cases and was tested prospectively and expanded by using 94 different cases. Sensitivity, specificity, predictive values, and receiver operating characteristic curves were computed for all models. RESULTS: Individual features with high predictive values were MR visibility, enhancement degree and pattern, focal mass border characteristics, and focal mass internal septations. Feature combinations with high negative predictive values for malignancy were absence of an MR-visible abnormality, focal masses with smooth borders, lobulated or irregular masses with nonenhancing internal septations, and focal masses with no (or minimal) enhancement. The validated- and revised-model performance characteristics were, respectively, as follows: sensitivity, 100% and 96%; specificity, 69% and 79%; positive predictive value, 75% and 76%; negative predictive value, 100% and 97%; and overall accuracy, 83% and 86%. CONCLUSION: An interpretation model that incorporates breast MR architectural features can achieve high sensitivity and improve specificity for diagnosing breast cancer.

High-resolution MR imaging of the breast: clinical context.

Preliminary investigation into magnetic resonance (MR) imaging as a breast imaging technique has demonstrated several promising roles for this modality when used as an adjunct to mammography for the detection and diagnosis of breast cancer. There are many technical factors that must be considered, including high resolution, rapid imaging, fat suppression, and localization and biopsy capability. Potential clinical applications include differentiating benign from malignant lesions, detecting cancer when results of clinical examination or conventional imaging are equivocal, detecting cancer recurrence after breast conservation treatment, staging newly diagnosed breast cancer, and detecting occult cancer in patients presenting with axillary node metastasis. Pitfalls include false-positive and false-negative results. Awareness of the strengths and limitations of MR imaging of the breast will facilitate integration of this technique into the work-up of patients with suspicious breast lesions.

Staging of suspected breast cancer: effect of MR imaging and MR-guided biopsy.

PURPOSE: To investigate the effect of contrast material-enhanced magnetic resonance (MR) imaging on staging of breast cancer in patients with mammographically or clinically suspected tumor. MATERIALS AND METHODS: One hundred seventy-six patients underwent breast MR imaging at 1.5 T before excisional biopsy of a suspicious mammographic or palpable abnormality. Diagnostic imaging studies in patients with biopsy-proved or presumed breast carcinoma were reviewed. RESULTS: Sixty-four patients met the study criteria. MR imaging enabled detection of all 57 invasive breast cancers and nine of 15 in situ cancers. In 22 patients (34%), MR imaging depicted one or more cancers not visible at mammography, 13 (20%) of which were unsuspected multifocal or diffuse disease. As a result of the increased sensitivity of MR imaging compared with that of mammography, clinical staging and subsequent treatment were altered in seven patients (11%). CONCLUSION: MR imaging allows detection of mammographically and clinically occult foci of carcinoma in patients with suspected breast cancer.