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

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.

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.

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).

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.