Ring lesions in MR imaging of the liver

The purpose of this study is to find some points that may help the differential diagnosis of ring lesions in magnetic resonance (MR) imaging of the liver through recognition of the characteristics of the morphology and the signal intensities of the ring lesions. T1-and T2-weighted axial spin-echo images and gadolinium-enhanced T1-weighted images were obtained with a 1.0 T superconducting MR imager. We reviewed the MR findings of 23 hepatic ring lesions which were confirmed as hepatocellular carcinomas (13), metastases (4), liver abscesses (4), hydatid cyst (1), and hematoma (1). There were 19 single rings and 4 double rings (all the cases were liver abscesses) on T1-weighted images, and 8 single rings and 14 double rings on T2-weighted images. The signal intensity of the ring was low in hepatocellular carcinoma on T1-weighted images and in hydatid cyst on T2-weighted images. It was high on T1-weighted images in subacute hematoma. Target lesion as an inner high-signal-intensity ring surrounded by a high-signal-intensity ring on T2-weighted images was seen in metastasis, liver abscess, and hepatocellular carcinoma. It is helpful to recognize the characteristics of morphology and signal intensities of the ring lesions in the differential diagnosis of hepatic focal lesions