Abbreviated liver magnetic resonance imaging with a second-shot arterial phase image to assess the viability of treated hepatocellular carcinoma after non-radiation locoregional therapy.

Purpose: To evaluate the feasibility of abbreviated liver magnetic resonance imaging (AMRI) with a second-shot arterial phase (SSAP) image for the viability of treated hepatocellular carcinoma (HCC) after non-radiation locoregional therapy (LRT).

Methods: We retrospectively enrolled patients with non-radiation LRT for HCC who underwent the modified gadoxetic acid-enhanced liver MRI protocol, which includes routine dynamic and SSAP imaging after the first and second injection of gadoxetic acid, respectively (6 mL and 4 mL, respectively), and an available reference standard for tumor viability in the treated HCC between March 2021 and February 2022. Two radiologists independently reviewed the full-protocol MRI (FP-MRI) and AMRI with SSAP. For the FP-MRI, observations were assigned using the Liver Imaging Reporting and Data System treatment response (LR-TR) algorithm v.2024. In the AMRI with SSAP, the observations were assigned using the abbreviated LR-TR category according to the arterial mass-like enhancement in SSAP. Ancillary features, such as diffusion restriction and T2-weighted mild-to-moderate hyperintensity, were also optionally used.

Results: Of the 95 patients (70 men and 25 women; mean age, 68.7 years), 42 (44.2%) had viable lesions and 53 (55.8%) had non-viable lesions. The scan time of the simulated AMRI was significantly shorter than the FP-MRI (7.6±0.49 and 23.6±0.50 min, respectively; p<0.001). For evaluating the viability of treated HCC, there were no significant differences in the sensitivity and specificity between the FP-MRI and AMRI with SSAP (sensitivity, 85.7% vs. 80.1%, P = 0.500; specificity, 96.2% vs. 96.2%, P = 1.000).

Conclusion: The abbreviated LR-TR score in AMRI with SSAP showed non-inferior diagnostic performance to FP-MRI in terms of evaluating the viability for the treated HCC, which may be helpful in clinical practice alongside a decreased scan time.

Clinical significance: Abbreviated liver MRI with SSAP may be helpful for evaluating the viability of treated HCC in practice, while also providing a decreased scan time.