Abstract: Objective To analyze the magnetic resonance imaging (MRI) characteristics of the injury type and severity of drug-induced liver injury. Methods The clinical data of 120 patients with drug-induced liver injury who were diagnosed and treated in our hospital from January 2020 to December 2024and received MRI examination were retrospectively analyzed, and the MRI characteristics of patients with different injury types and disease severity were analyzed. Results The main MRI features observed in DILI patients included irregular liver surface, intrahepatic bile duct dilatation, gallbladder wall thickening, and splenomegaly. Among different injury types, the ADC values of the hepatocellular and mixed injury types [824.5 (526.5~1 114.6) ×10^-6 mm²/s and 890.2 (621.5~1 268.1) ×10^-6 mm²/s, respectively] were significantly lower than those of the cholestatic type [1 126.3 (818.6~1 268.4) ×10^-6 mm²/s, P<0.05]. Comparison among patients with varying disease severity showed that the incidence of intrahepatic bile duct dilatation in patients with grade ≥3 was 32.5%, significantly higher than that in patients with grade ≤2 (22.5%, P<0.05). The incidence of gallbladder wall thickening was also higher in grade ≥3 patients (52.5%) than in grade ≤2 patients (30.0%, P<0.05), while ADC values were markedly reduced [846.2 (621.5~1 150.8) ×10^-6 mm²/s vs. 1 058.6 (856.4~1 268.4) ×10^-6 mm²/s, P<0.05]. According to the causative drug categories, the incidence of intrahepatic bile duct dilatation was the highest in the traditional Chinese medicine and Chinese patent medicine group (55.2%), significantly higher than that in the antibacterial (20.0%), antineoplastic (18.7%), and cardiovascular drug groups (23.5%, P<0.05). The incidence of gallbladder wall thickening was also the highest in the traditional Chinese medicine and Chinese patent medicine group (58.6%), followed by the antineoplastic drug group (50.0%, P<0.05). The ADC value was the lowest in the antineoplastic drug group [812.3 (554.6~986.4) ×10^-6 mm²/s], followed by the traditional Chinese medicine and Chinese patent medicine group [826.7 (526.5~936.8) ×10^-6 mm²/s], both were significantly lower than those in other groups (P<0.05). Conclusion The common MRI features of DILI patients include irregular liver surface, intrahepatic bile duct dilatation, gallbladder wall thickening and splenomegaly. There were no significant differences between different types of patients, but there is a certain degree of differentiation between intrahepatic bile duct dilatation and gallbladder wall thickening in different severity and drug categories.

Key words: Drug-induced liver injury, Injury type, Disease severity, MRI features