Update on multidetector computed tomography angiography of the abdominal aorta.

Multidetector computed tomography angiography (MDCTA) allows high spatial resolution, including nearly isotropic submillimeter resolution in the X, Y, and Z planes, and rapid image acquisition in a single breath hold, with greatly enhanced diagnostic capabilities over conventional CT. MDCTA has largely replaced digital subtraction angiography because it is faster, less invasive, and provides more information. When technical parameters are optimized, it provides the radiologist with the information needed to diagnose life threatening diseases of the aortoiliac system, gives critical information for the vascular surgeon or interventional radiologist to treat that disease, and identifies subsequent complications related to therapy. This article briefly discusses the technical components and optimization of MDCTA of the abdominal aorta and iliac arteries (aortoiliac system) and examines the diseases of the aortoiliac system evaluated by MDCTA.

Adding in vivo quantitative 1H MR spectroscopy to improve diagnostic accuracy of breast MR imaging: preliminary results of observer performance study at 4.0 T.

PURPOSE: To determine whether the addition of in vivo quantitative hydrogen 1 (1H) magnetic resonance (MR) spectroscopy can improve the radiologist's diagnostic accuracy in interpreting breast MR images to distinguish benign from malignant lesions. MATERIALS AND METHODS: The study was approved by the institutional review board and, where appropriate, was compliant with the Health Insurance Portability and Accountability Act. All patients provided written informed consent. Fifty-five breast MR imaging cases-one lesion each in 55 patients aged 24-66 years with biopsy-confirmed findings-were retrospectively evaluated by four radiologists. Patients were examined with contrast material-enhanced fat-suppressed T1-weighted 4.0-T MR imaging. The concentration of total choline-containing compounds (tCho) was quantified by using single-voxel 1H MR spectroscopy. For each case, the radiologists were asked to give the percentage probability of malignancy, the Breast Imaging and Reporting Data System category, and a recommendation for patient treatment. Two interpretations were performed for each case: The initial interpretation was based on the lesion's morphologic features and time-signal intensity curve, and the second interpretation was based on the lesion's morphologic features, time-signal intensity curve, and tCho concentration. Receiver operating characteristic (ROC), Wilcoxon signed rank, kappa statistic, and accuracy (based on the area under the ROC curve) analyses were performed. RESULTS: Of the 55 lesions evaluated, 35 were invasive carcinomas and 20 were benign. The addition of 1H MR spectroscopy resulted in higher sensitivity, specificity, accuracy, and interobserver agreement for all four radiologists. More specifically, two of the four radiologists achieved a significant improvement in sensitivity (P=.03, P=.03), and all four radiologists achieved a significant improvement in accuracy (P = .01, P = .05, P = .009, P < .001). CONCLUSION: Current study results suggest that the addition of quantitative 1H MR spectroscopy to the breast MR imaging examination may help to improve the radiologist's ability to distinguish benign from malignant breast lesions.