OBJECTIVETo analyze the magnetic resonance imaging (MRI) findings of radiation-induced liver injury following three-dimensional conformal radiotherapy.

METHODSA retrospective review of the MRI data was conducted in 20 patients treated between September 2000 and October 2005, who suffered liver injuries induced by 1 or 2 three-dimensional conformal radiotherapy sessions for liver neoplasm. The patients underwent MR scans with T2-weighted sequences and T1-weighted sequences in both plain and Gd-DTPA enhanced MRI. Four patients with suspected tumor relapse suggested by MRI were pathologically confirmed to have radiation-induced liver injury.

RESULTSAcute radiation-induced liver injury was represented by large patches of liver edema consistent with the irradiation volume, showing low signal intensity on T1-weighted images (T1WI) and high signal intensity on T2-weighted images (T2WI) without arterial phase enhancement after Gd-DTPA injection. Delayed radiation-induced liver injury was manifested by slightly low-intensity signal on plain T1WI and slightly high-intensity signal on T2WI without obvious arterial phase enhancement following Gd-DTPA injection but with marked enhancement during the portal-venous and delayed phases.

CONCLUSIONRadiation-induced liver injury presents characteristic MRI features, and plain and dynamic enhanced MRI can be of great value for its diagnosis.