Performance of gadoxetic acid MRI and diffusion-weighted imaging for the diagnosis of early recurrence of hepatocellular carcinoma.

ABSTRACT

OBJECTIVE: To determine the diagnostic accuracy and predictive value of gadoxetic acid liver MRI (Gd-EOB-DTPA MRI) alone or in combination with diffusion-weighted imaging (DWI) as a second-line tool for detecting early hepatocellular carcinoma (HCC) recurrence in cirrhotic patients with previous HCC treated with resection or ablation. METHODS: Between 2014 and 2017, we prospectively included 34 cirrhotic patients with complete response to resection and/or ablation of early HCC in whom a new focal lesion enhancing in the arterial phase without washout was detected during follow-up with EC-MRI. After signing the informed consent, all patients underwent DWI and Gd-EOB-DTPA MRI; two readers analyzed signal intensities on each phase of dynamic study and on DWI. The final diagnosis was established by histology or follow-up EC-MRI. We used cross-tabulation to calculate indices of diagnostic accuracy. RESULTS: We evaluated 34 patients (7 women; 73.5% with hepatitis C virus) with a total of 53 new arterial-phase-enhancing foci (median size, 10 [IQR 9-14] mm). The final diagnosis, reached by histopathology in 15 (35.7%) lesions and EC-MR follow-up in 27 (64.3%), was HCC in 42 (79.2%) and benign conditions in 11 (21.8%). Hepatobiliary-phase hypointensity on Gd-EOB-DTPA MRI plus hyperintensity on DWI yielded 54.8% sensitivity, 90.9% specificity, 95.8% positive predictive value, and 34.5% negative predictive value for diagnosing HCC recurrence. CONCLUSION: Among potential indices, combining hypointensity on hepatobiliary-phase Gd-EOB-DTPA MRI and hyperintensity on DWI has the highest specificity and positive predictive value to optimally detect HCC recurrence prior to confident diagnosis by conventional imaging criteria on EC-MRI in cirrhotic liver. KEY POINTS • In patients at risk of HCC recurrence, the use of gadoxetic acid liver MRI and DWI may improve the differentiation of unspecific new arterial-enhancing foci from early hypervascular HCC recurrence in patients with non-conclusive findings on extracellular liver MRI. • Combined findings on hepatobiliary-phase gadoxetic acid-enhanced liver MRI and DWI had high specificity (90.9%) and positive predictive value (95.8%) for detecting early hypervascular HCC recurrence, but limited sensitivity. • Combining hepatobiliary-phase hypointensity on gadoxetic acid MRI and hyperintensity on diffusion-weighted imaging allows early diagnosis of hypervascular hepatocellular carcinoma and may help select patients for salvage therapy.