Serial MRI in opioid-associated amnestic syndrome

Gadolinium-enhanced MRI on day 7 shows bilateral gyriform hippocampal apparent diffusion coefficient hypointensity (A) with corresponding hyperintensity on diffusion-weighted imaging (B), indicating restricted hippocampal diffusivity (arrows). Hippocampal T₂ hyperintensity (C; dashed arrows) along with subtle hippocampal gadolinium enhancement (D; thick arrows) is also seen. Follow-up MRI on day 12 shows resolution of hippocampal restricted diffusion (E) and resolution of T₂ hyperintensity (F).