Usefulness Of Diffusion-weighted MR In Differential Diagnosis Of Primary Malignant Liver Tumors Enhanced In Delayed Phase From Haemangiomas

PrefacePart of primary malignant liver tumors are not enhanced significantly in the arterial phase and showed progressive peripheral enhancement during portal phase and delayed phase, which were difficult to differentiate them from atypical haemangiomas.PurposeTo investigate the usefulness of diffusion-weighted imaging(DWI) in differential diagnosis of haemangiomas and primary malignant liver tumors enhanced in delayed phase.Materials and MethodsDiffusion weighted MR scans were performed using a 1.5 T MR unit (Gyroscan Intera; Philips Medical Systems) at b value of 500 s/mm2 on 32 patients with focal hepatic lesions enhanced in delayed phase.11 of these patients with haemangiomas,21 with primary malignant tumors (9 with hepatocellular carcinomas,12 cholangiocarcinomas). Quantitative analysis was performed using the regions of interest (ROI) method settled on the lesions. The ADCs of each ROI among haemangiomas, hepatocellular carcinomas and cholangiocarcinomas were calculated and analyzed by student t test respectively. A P value of less than 0.05 was considered to indicate statistical significance.ResultsThe mean ADC value of hepatocellular carcinomas(1.28±0.46×10-3) and cholangiocarcinomas(1.61q0.38×10-3 mm2/s) were significantly lower than that of hemangioma (2.85±0.89×10-3 mm2/s) (t=4.780, P=0.000;t=3.7025, P=0.001). However,there were no significant difference of ADC values between hepatocellular carcinomas and cholangiocarcinomas(t=1.8008, P=0.088). ConclusionsAlthough not able to diffentiate the pathological types, DWI may be helpful to differentiae hemangiomas from primary malignant liver tumors enhanced in delayed phase.