Value of Gd-EOB-DTPA-Enhanced MRI and Diffusion-Weighted Imaging in Detecting Residual Hepatocellular Carcinoma After Drug-Eluting Bead Transarterial Chemoembolization

Rationale and Objectives: To investigate the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in diagnosing residual hepatocellular carcinoma (HCC) after drug-eluting bead transarterial chemoembolization (DEB-TACE). Materials and Methods: Sixty-two patients (50 men, 12 women; mean age, 56.8 +/- 1.4 years) with 74 HCCs who underwent Gd-EOBDTPA-enhanced MRI and DWI in 1-2-month intervals after DEB-TACE were retrospectively studied. Imaging features derived from GdEOB-DTPA-enhanced MRI and DWI were analyzed and compared between residual HCCs and necrotic tumors. The sensitivity and specificity of Gd-EOB-DTPA-enhanced MRI and DWI with quantitative apparent diffusion coefficient (ADC) values in diagnosing residual HCCs were calculated and compared, based on the reference standard of pathology and/or angiography. Results: Thirty-three residual HCCs and 41 necrotic tumors were diagnosed. Residual HCCs presented characteristics of arterial hypervascularity (90.91%) and DWI hyperintensity (78.78%), which were of importance in differentiating necrotic tumors (p < 0.05). DWI showed lower sensitivity (78.79% vs. 96.97%, p < 0.001) and specificity (78.05% vs. 100%, p < 0.001) than Gd-EOB-DTPA-enhanced MRI in diagnosing residual HCCs after DEB-TACE. Residual HCCs had a significantly higher mean ADC value than necrotic tumors (1.30 +/- 0.32 x 10(-3) mm(2)/s vs. 1.55 +/- 0.50 x 10(-3) mm(2)/s, p < 0.001). Receiver operating characteristic curve analysis for identifying residual HCCs demonstrated that the threshold ADC value of 1.25 x 10(-3) mm(2)/s had 84.85% sensitivity and 87.80% specificity. Conclusion: Gd-EOB-DTPA-enhanced MRI is superior to DWI in diagnosing residual HCCs after DEB-TACE, and arterial hypervascularity and DWI hyperintensity are important imaging features in distinguishing residual HCCs from necrotic tumors.