Detection of liver malignancy with gadoxetic acid-enhanced MRI: Is addition of diffusion-weighted MRI beneficial?

AimTo determine the additive value of diffusion-weighted MRI (DWI) to gadoxetic acid-enhanced MRI for the detection of hepatic metastases and hepatocellular carcinoma (HCC).Materials and MethodsThirty-five patients with 38 liver metastases and 18 HCCs were included in this study. Ten patients also had hemangiomas (n = 3) or cysts (n = 8). Liver MRI consisted of pre-contrast and gadoxetic acid-enhanced 3D T1-weighted MRIs (arterial, portal, 2-min delay, 20 min hepatocyte-selective phases), a post-contrast T2-weighted image, and post-contrast DWI (b values: 0, 50, 600 s/mm2). Two observers independently analyzed the gadoxetic acid-enhanced MRI with and without DWI. The diagnostic accuracy and sensitivity for the detection of liver lesions were evaluated using receiver operating characteristic analysis.ResultsAlthough there were no significant differences in diagnostic accuracy for detecting metastases and HCCs between the gadoxetic acid set alone and the combined DWI and gadoxetic acid set for both observers (mean Az, 0.974 vs 0.987), we found the sensitivity for detecting metastases to be significantly higher with the combined images (97.4%) than with the gadoxetic acid set alone (89.5%) for observer 1 (p = 0.008). Three and two metastases for each observer were clearly verified by adding DWI to gadoxetic acid-enhanced MRI. However, sensitivities for both image sets were equivalent in detecting HCCs.ConclusionThe addition of DWI to gadoxetic acid-enhanced MRI has the potential to increase sensitivity for the detection of liver metastases. However, for detecting HCC, we found no additive value of DWI to gadoxetic acid-enhanced MRI.