[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 (P<0.05).

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.