Detection of small hepatocellular carcinoma using gadoxetic acid-enhanced MRI: Is the addition of diffusion-weighted MRI at 3.0T beneficial?

Objective: To determine whether adding diffusion-weighted imaging (DWI) to gadoxetic acid-enhanced 3.0T magnetic resonance imaging (MRI) can improve the detection of hepatocellular carcinoma (HCC), particularly for small lesions (≤2 cm) in patients with liver cirrhosis.

Methods: Data of patients diagnosed with focal liver lesions who had undergone gadoxetic acid-enhanced 3.0T MRI and DWI were retrospectively reviewed. Two radiologists (the observers) reviewed independently MRI images in two reading sessions, that is, gadoxetic acid-enhanced images alone and the combination of DWI (b values: 0 and 600 s/mm(2) ) and gadoxetic acid-enhanced images. They assigned to each lesion a confidence level based on a five-point scale. The area under the receiver operating characteristic curve (AUROC), sensitivity and positive predictive value (PPV) for the detection of HCC were calculated.

Results: Both observers found the AUROC of the gadoxetic acid-enhanced images was slightly higher than that of the combined DWI and gadoxetic acid-enhanced MRI images in the detection of HCC (observer 1: 0.947 ± 0.030 vs 0.896 ± 0.042, Z = 1.478, P = 0.139; observer 2: 0.917 ± 0.038 vs 0.868 ± 0.048, Z = 1.296, P = 0.195). The sensitivity for the gadoxetic acid set alone was slightly higher than that for the combined set for observer 1 (97% vs 84%) and slightly lower for observer 2 (74% vs 82%). The PPVs were slightly higher for the gadoxetic acid set alone than for the combined set for both observers (observer 1, 89% vs 80%; observer 2, 93% vs 78%); however, none of the differences were statistically significant (P > 0.05).

Conclusion: There is no benefit in adding DWI to gadoxetic acid-enhanced MRI for the detection of HCC at 3.0T.