We assessed the usefulness and limitations of utilizing apparent diŠusion coe‹cient (ADC) values on diŠusion-weighted imaging (DWI) for the diŠerential 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 68.8z; speciˆcity, 63.6z; positive predictive value (PPV), 73.3z; negative predictive value (NPV), 58.3z; and accuracy, 66.7z. Kinetic curve analysis did not reliably diŠerentiate benign and malignant non-mass-like lesions. There was no signiˆcant diŠerence 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 eŠective threshold of ADC value for diŠerentiating 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 68.8z; speciˆcity, 72.7z; PPV, 78.6z; NPV, 61.5z; and accuracy, 70.4z. Combining the ADC value criteria with the analysis of DCE-MRI pattern increased sensitivity to 93.8z, negative predictive value (NPV) to 85.7z, and accuracy to 77.8z but decreased speciˆcity to 54.5z. Use of ADC values does not adequately improve DCE-MRI performance for diŠerential diagnosis of non-mass-like breast lesions, but adding the ADC value criteria to the DCE-MRI pattern analysis improves sensitivity, NPV, and accuracy.

The presence of the IVC niveau sign suggests acute cardiac tamponade in patients with acute type A aortic dissection.