Acute Hepatic Encephalopathy: Diffusion-Weighted and Fluid-Attenuated Inversion Recovery Findings, and Correlation with Plasma Ammonia Level and Clinical Outcome

A 53-year-old man (patient 8) with acute confusion in the setting of ACHF (maximal PAL, 101 μmol/L). A−C, There is symmetric bilateral bright signal intensity in the thalami (arrows) and PLIC (thin arrows) on FLAIR (A) and DWI (B), confirmed to have reduced diffusion on ADC maps (C). D, Abnormalities are also noted in the PVWM (arrows) on FLAIR and DWI (not shown). The extent of abnormalities is graded as “moderate” on DWI and “severe” on FLAIR. The symptoms had mostly resolved 16 days later.

A 10-year-old girl with confusion (patient 14) from acute hepatic encephalopathy after acetaminophen overdose (maximal PAL, 104 |gmmol/L). A and B, There is predominately brain stem and thalamic involvement; the initial MR images show mild DBS hyperintensity (double arrows) on FLAIR (A) and T2WI (B). Abnormalities were also noted in the thalami (not shown); the severity was graded as “minimal” on both FLAIR and DWI (not shown). C and D, The brain stem findings have improved on MR images at 5 days, though a small frontal parenchymal hemorrhage has occurred, and soon after, the symptoms resolved completely by 13 days.

A 34-year-old confused man (patient 12) after acetaminophen overdose (maximal PAL, 206 |gmmol/L). A and B, Bilateral symmetric “severe” involvement includes abnormalities within the thalami (arrows) with diffuse cortical involvement (thin arrows), as noted on FLAIR (A) and DWI (B). C and D, On FLAIR (C) and DWI (D) 93 days later, there is complete resolution of the abnormalities, with a mild residual neurologic deficit.