Diagnostic performance of ADC for Non-mass-like breast lesions on MR imaging.

We assessed the usefulness and limitations of utilizing apparent diffusion coefficient (ADC) values on diffusion-weighted imaging (DWI) for the differential diagnosis of benign and malignant non-mass-like breast lesions. We retrospectively reviewed 27 such lesions (16 malignant, 11 benign) detected on magnetic resonance (MR) imaging and analyzed the enhancing patterns of dynamic contrast-enhanced DCE-MRI (distribution and internal enhancement), kinetic curve patterns, and ADC values. All images were obtained with a 1.5-tesla MR unit, with patients supine. On DCE-MRI, malignant lesions tended to show either segmental or branching-ductal distribution, and when lesions with these patterns were considered malignant, sensitivity was 68.8%; specificity, 63.6%; positive predictive value (PPV), 73.3%; negative predictive value (NPV), 58.3%; and accuracy, 66.7%. Kinetic curve analysis did not reliably differentiate benign and malignant non-mass-like lesions. There was no significant difference between the mean ADC value of the malignant lesions, 0.968 × 10(-3) mm(2)/s at b=1000 s/mm(2), and that of benign lesions, 1.207 × 10(-3) mm(2)/s (P=0.109). Receiver operating characteristic (ROC) analysis revealed the most effective threshold of ADC value for differentiating tumors as 1.1 × 10(-3) mm(2)/s; values lower than this were observed more often in malignant than benign lesions (P=0.054). Us of this threshold yielded sensitivity of 68.8%; specificity, 72.7%; PPV, 78.6%; NPV, 61.5%; and accuracy, 70.4%. Combining the ADC value criteria with the analysis of DCE-MRI pattern increased sensitivity to 93.8%, negative predictive value (NPV) to 85.7%, and accuracy to 77.8% but decreased specificity to 54.5%. Use of ADC values does not adequately improve DCE-MRI performance for differential diagnosis of non-mass-like breast lesions, but adding the ADC value criteria to the DCE-MRI pattern analysis improves sensitivity, NPV, and accuracy.

Contrast-fluid level in the inferior vena cava (IVC niveau sign) in patients with acute type A aortic dissection: computed tomography findings during acute cardiac tamponade.

PURPOSE: The purpose of this study was to report a new computed tomography (CT) finding in acute cardiac tamponade: a contrast-fluid level in the hepatic inferior vena cava (IVC) during an arterial dominant phase CT study (IVC niveau sign) in patients with acute type A aortic dissection. MATERIALS AND METHODS: We retrospectively reviewed CT studies with the diagnosis of proximal aortic dissection (Stanford type A) with acute cardiac tamponade. There were 12 patients enrolled in the study (6 women, 6 men; mean age 66 years). A total of 62 patients were selected as a control chronic pericardial effusion group to compare with the acute cardiac tamponade group. RESULTS: Among the 12 patients with acute cardiac tamponade, the IVC niveau sign was seen in 7 (58%). In the control chronic pericardial effusion group (n = 62), we identified the IVC niveau sign in only one patient (1.6%). There was a significant difference in the presence of the IVC niveau sign between the acute cardiac tamponade and chronic pericardial effusion groups (P < 0.0001). CONCLUSION: The presence of the IVC niveau sign suggests acute cardiac tamponade in patients with acute type A aortic dissection.