Focal Hepatic Lesions: Dynamic Multi-slice MR Imaging

ABSTRACT

PURPOSE: To evaluate the dynamic enhancement patterns of focal hepatic lesions using breath-hold dynamic MR imaging for differential diagnosis. MATERIALS AND METHOD: Thirty three patients (24 men and 12 women, mean age of 55 years) with 56 known liver masses on CT scan and US underwent MR imaging with 1.5T. After Tl-weighted fast multiplanar spoiled gradient recalled (FMPSPGR) imaging, breath-hold FMPSPGR images were obtained at 0, 1, 3, 5, and 10 minutes after bolus injection of Gd-DTPA. The cases consisted of 16 hepatocellular carcinomas, 24 hemangiomas, 6 metastases, 3 cholangiocellular carcinomas, and 7 hepatic cysts. The dynamic enhancement patterns were evaluated on the basis of initial enhancement study and, the degree of enhancement was also levaluaied. RESULTS: Of 24 hemangiomas, most cases showed centripetal filling-in pattern of enhancement except 3 cases which showed homogeneous enhancement pattern on the early dynamic phase. All hemangiomas showed very high signal intensity which persisted to the delayed phase. The eccentric enhancement pattern was the most common type in hemangiomas (63%). Hepatocellular carcinomas had heterogeneous enhancement pattern on early and delayed phase (81, 88%) and showed diminished signal intensity on the delayed images. 14 of 16 hepatocellular carcinomas (88%) had peritumoral halo. Variable enhancement pattern was observed in metastases including progressive centripetal filling-in pattern (67%). All metastases showed prominent peritumoral halos and low signal intensity. Cholangiocellular carcinomas showed early centripetal filling-in and heterogeneous enhancement pattern on delayed phase. None of hepatic cysts showed enhancement. CONCLUSIONS: Dynamic breath-hold MR imaging with Gd enhancement allows accurate assessment of hemodynamic status of hepatic lesions and is useful in differential diagnosis of focal hepatic lerions.