[Small hepatocellular carcinoma in patients with hepatitis B-induced cirrhosis: a comparison between MRI and MDCT].

Objective:To compare efficacy of plain and contrast enhancement MRI (1.5T or 3T) and dynamic contrast enhanced multidetector CT (MDCT,16- or 64-slice) for the detection of small hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis. Methods: A total of 21 patients (18 men,3 women; age range,44-74 years) with 22 small HCC and liver cirrhosis were enrolled,all having undergone MDCT and MRI within one month. The diagnosis of small HCC was established at surgical resection (n=4),percutaneous biopsy (n=1),with positive tumor staining at intervention or from combined clinical data,typical imaging features and follow-up for a period of at least one year. Triple-phase or dual-phase dynamic contrast enhancement was performed on a 16- or 64-slice MDCT. MRI sequences included transverse T1-weighed images acquired as fast spoiled gradient (FSPGR) in-phase and out-of-phase dual-echo,transverse T2-weighed images with respiratory triggering acquired as fat-suppressed fast spin echo (FSE) or fast recovery fast spin echo (FRFSE),and breath-hold coronal T2-weighed images acquired as single shot fast spin echo (SSFSE) or fast imaging employing steady-state acquisition (FIESTA). CT and MRI observers independently analyzed each image in random order and marked each lesion detected with a score,ranking from 1 to 5 (1 definitely benign,2 possibly benign,3 undetermined,4 possible HCC,and 5 definite HCC),then receiver operating characteristic (ROC) curve and Chi-square analysis were adopted to compare the efficacy for MDCT and MRI imaging. Results: Although no significant difference was demonstrated at the comparison of sensitivity and specificity (sensitivity and specificity of MDCT: 70%,50%; sensitivity and specificity of MRI 86.36%,100%; sensitivity χ2=0.835,P=0.360; specificity χ2=1.379,P=0.240),the Az (area under the ROC curve) for MRI imaging (mean,0.974) was much higher than that for MDCT (mean,0.795) with significant difference (P0.05). Conclusion: MRI imaging shows better diagnostic accuracy for the detection of small HCC in patients with hepatitis B-induced cirrhosis and is recommended to improve the detection and diagnosis.