Gd-EOB-DTPA enhanced MRI for hepatocellular carcinoma. Quantitative evaluation of tumor enhancement in hepatobiliary phase

The purpose of this study was to evaluate the utility of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for the quantitative evaluation of hepatocellular carcinoma (HCC) and dysplastic nodules in the hepatobiliary phase. The subjects comprised 12 patients with 27 lesions (22 HCCs and 5 dysplastic nodules). Chemical-shift-selective fat-suppressed T1-weighted sequences were obtained before and 10, 20, and 40 min after the injection of Gd-EOB-DTPA. Quantitative analyses were performed with the enhancement ratio of the lesion and the contrast-to-noise (C/N) ratio. The enhancement ratios of the HCCs were 44.0±36.5, 44.7±46.8, and 47.7±52.8 (%) at 10, 20, and 40 min, respectively, after the injection of Gd-EOB-DTPA. The enhancement ratios of the dysplastic nodules were 36.2±34.3, 44.3±37.3, and 40.1±46.8 (%). The C/N ratios of the HCCs were 0.2±6.6 for the precontrast image, and -9.2±12.6, -9.9±14.8, and -12.7±15.7 at 10, 20, and 40 min, respectively, after the injection of Gd-EOB-DTPA. The C/N ratios of the dysplastic nodules were 1.4±8.0, -13.7±11.1, -13.3±7.6, and -13.1±10.4. No significant differences were found between the HCCs and the dysplastic nodules in the enhancement ratio and the C/N ratio. Only two HCCs showed a positive C/N ratio value, and these HCCs were pathologically confirmed to be a well differentiated and a moderately differentiated carcinoma, respectively. HCCs and some of the dysplastic nodules showed hypointensity in the hepatobiliary phase in Gd-EOB-DTPA-enhanced MRI. No specific enhancement was observed, regardless of tumor differentiation. (author)