Detection and characterisation of focal liver lesions in colorectal carcinoma patients: comparison of diffusion-weighted and Gd-EOB-DTPA enhanced MR imaging.

ABSTRACT

OBJECTIVE: To compare diffusion-weighted imaging (DWI) and Gd-EOB-DTPA-enhanced magnetic resonance (MR) imaging for the detection and characterisation of focal liver lesions (FLLs) in patients with colorectal carcinoma. METHODS: Seventy-three patients underwent MR imaging including echoplanar DWI (MR-DWI) and dynamic (MR-Dyn) and hepatobiliary phase (MR-Late) Gd-EOB-DTPA-enhanced images. Two blinded readers independently reviewed 5 different image sets using a 5-point confidence scale. Accuracy was assessed by the area (A(z)) under the receiver operating characteristic curve, and sensitivity and specificity were calculated. RESULTS: A total of 332 FLLs were evaluated. Detection rates were significantly higher for MR-Late images (94.4% for benign and 100% for malignant lesions) compared with MR-DWI (78.3% and 97.5%) and MR-Dyn images (81.5% and 89.9%). Accuracy was 0.82, 0.76 and 0.89 for MR-DWI, MR-Dyn and MR-Late images while sensitivity was 0.98, 0.87 and 0.95, respectively. For characterisation of subcentimetre lesions sensitivity was highest for MR-DWI (0.92). Combined reading of unenhanced and contrast-enhanced images had an identical high accuracy of 0.98. CONCLUSION: Late-phase Gd-EOB-DTPA-enhanced images were superior for the detection of FLLs, while DWIs were most valuable for the identification of particularly small metastases. Combined interpretation of unenhanced images resulted in precise characterisation of FLLs.