Gadobenate dimeglumine-enhanced liver MR imaging in cirrhotic patients: Quantitative and qualitative comparison of 1-hour and 3-hour delayed images

Purpose: To compare the image quality and diagnostic performance of 1- and 3-h delayed-phase MR images (DPIs) after gadobenate dimeglumine injection in detecting small hepatocellular carcinomas (HCCs) in cirrhotic patients. Materials and Methods: Relative enhancement of the liver (RE_liver) and HCC (RE_HCC) and liver-to-lesion contrast-to-noise ratio (CNR) of HCC were measured quantitatively on 1- and 3-h DPIs in 65 patients with 88 HCCs. For qualitative analysis, two radiologists independently evaluated three image sets in 19 patients with 25 HCCs ≤2 cm and in 16 controls without HCCs: conventional liver MR without DPI (set A), adding 1-h DPI (set B), and adding 3-h DPI (set C), using a 5-point scale for diagnosing small HCCs. Diagnostic performance for small HCCs was analyzed using the alternative free-response receiver operating characteristic method. Results: Mean RE_liver (P = 0.013) and RE_HCC (P < 0.001) were significantly higher on 1-h than on 3-h DPI, whereas CNR was significantly higher on 3-h than on 1-h DPI (P = 0.001). Observer-averaged figure of merit (FOM) was significantly higher for set C than for set A (0.942 versus 0.883; P = 0.013). Conclusion: In cirrhotic patients, 3-h DPI provides a higher liver-to-lesion contrast and a better diagnostic performance for small HCCs than 1-h DPI.