Non-contrast magnetic resonance imaging for detection of late recurrent hepatocellular carcinoma after curative treatment: a prospective multicenter comparison to contrast-enhanced computed tomography.

[BACKGROUND/AIMS] Hepatocellular carcinoma (HCC) frequently recurs after curative treatment, posing challenges to long-term survival. Although contrast-enhanced multiphasic computed tomography (CECT) is commonly used for detecting recurrence, it is associated with risks such as radiation exposure and contrast agent reactions. This study aimed to compare the diagnostic performance of non-contrast magnetic resonance imaging (NC-MRI) with CECT for detecting recurrent HCC.

[METHODS] In this prospective multicenter intra-individual head-to-head comparison trial (study identifier: NCT05690451, KCT0006395), participants who had undergone curative treatment for HCC and remained recurrence-free for over two years were enrolled. Each participant underwent three follow-up imaging sessions at 2-6-month intervals using both CECT and NC-MRI. The primary outcome was the detection accuracy of each modality, analyzed using the generalized estimating equation analysis. Secondary outcomes included sensitivity and specificity.

[RESULTS] The study included 203 participants with a total of 528 paired imaging sessions, identifying recurrent HCC in 22 cases (10.8%). Among these, 21 cases involved intrahepatic recurrence with a median tumor size of 1.3 cm, and one case had aortocaval lymph node metastasis. NC-MRI achieved a detection accuracy of 96.6% (196/203), higher than CECT's 91.6% (186/203) (P=0.006). NC-MRI also showed greater sensitivity (77.3% [17/22] vs. 36.4% [8/22]; P=0.012), while specificity was comparable between NC-MRI and CECT (98.9% [179/181] vs. 98.3% [178/181]; P=0.999).

[CONCLUSION] NC-MRI demonstrated higher sensitivity and accuracy compared to CECT in detecting recurrent HCC in patients who had been disease-free for over two years following curative treatment, indicating its potential as a preferred imaging modality for this purpose.