Detection of small (≤2 cm) HCC in cirrhotic patients: added value of diffusion MR-imaging

Objectives To evaluate the usefulness of the diffusion-weighted sequence in the detection of small (≤2 cm) hepatocellular carcinoma (HCC) in patients with cirrhosis. Methods Seventy cirrhotic patients with 93 HCCs underwent MR-Imaging at 1.5 T. MR acquisitions comprised unenhanced T1- and T2-weighted images and post-contrast Gd-BOPTA-enhanced T1W GRE-3D images acquired after approximately 25, 60, 180 s (dynamic phases) and 90 min (hepatobiliary phase). DWI was performed by a SSEPI sequence (b values 0, 50, 400, 800 s/mm2). Quantitative analysis was performed to establish significant difference of ADC values of benign lesions compared with that of HCC. Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of two different protocols with and without diffusion MRI sequence were also calculated and compared each other. Results A good inverse correlation was found between reference standard and ADC values (ρ = −0.688). The mean ADC value of HCC was significantly lower than the mean value of benign focal liver lesions (p < 0.0001). No significant difference was reported in term of sensitivity, specificity, PPV, NPV and diagnostic accuracy between the two datasets. A trend to a better sensitivity was found when DWI images were considered. Conclusions The adjunction of DWI does not significantly improve the diagnostic accuracy in the detection of small HCC.