TY - JOUR T1 - Acute Hepatic Encephalopathy: Diffusion-Weighted and Fluid-Attenuated Inversion Recovery Findings, and Correlation with Plasma Ammonia Level and Clinical Outcome JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1471 LP - 1479 DO - 10.3174/ajnr.A2112 VL - 31 IS - 8 AU - A. M. McKinney AU - B.D. Lohman AU - B. Sarikaya AU - E. Uhlmann AU - J. Spanbauer AU - T. Singewald AU - J.R. Brace Y1 - 2010/09/01 UR - http://www.ajnr.org/content/31/8/1471.abstract N2 - BACKGROUND AND PURPOSE: In acute hepatic encephalopathy, MR imaging abnormalities have been described in the PVWM, thalami, and corticospinal tracts. We sought to determine characteristic regions of involvement on FLAIR and DWI, to evaluate their reversibility, and to correlate MR imaging extent with clinical severity. MATERIALS AND METHODS: Twenty patients who presented clinically with acute hepatic encephalopathy and MR imaging <21 days after symptom onset were reviewed retrospectively. Two neuroradiologists recorded involved regions on FLAIR and DWI in each, measured ADC values in affected regions and NAWM, and scored the MR imaging severity/extent. The initial severity (West Haven grade), follow-up clinical severity (degree of improvement), and maximal PAL within ±8 days of MR imaging were recorded and correlated with the MR imaging severity. RESULTS: On FLAIR and DWI respectively, there were abnormalities in the thalami (85%, 70%), PLIC (75%, 80%), PVWM (80%, 85%), and DBS (70%, 35%) and diffuse cortical involvement (30%, 25%). There were relatively strong significant (P < .005) correlations of FLAIR (r = 0.680, P = .001) and DWI severity (r = 0.690, P = .001) with PAL, and of PAL with the clinical outcome (r = 0.691, P = .001). Both FLAIR (r = 0.592, P = .006) and DWI (r = 0.487, P = .029) severity correlated moderately with the clinical outcome but were not significant at the P < .005 level after Bonferroni correction. CONCLUSIONS: Patients with acute hepatic encephalopathy may exhibit characteristic regions of involvement on FLAIR with DWI findings that can be reversible. The MR imaging extent on FLAIR and DWI strongly correlates with the maximal PAL, and PAL correlates well with the clinical outcome. Diffuse cortical involvement has a higher potential for neurologic sequelae but can be reversible. ACHFacute hepatic encephalopathy superimposed on chronic hepatic failureADCapparent diffusion coefficientAHFacute hepatic failureAODacetaminophen overdoseCNScentral nervous systemCWMcerebellar white matterddaysDBSdorsal brain stemDCIdiffuse cortical involvementDWIdiffusion-weighted imagingFLFLAIRFLAIRfluid-attenuated inversion recoveryF-Ufollow-upGPglobus pallidusIPHintraparenchymal hemorrhageMRIMR imagingN/Anot availableNAWMnormal-appearing white matternlnormalNOSnot otherwise statedPALplasma ammonia level (maximal)PLICposterior limb of the internal capsulePVWMperiventricular white matterSxsymptomT1WIT1-weighted imagingT2WIT2-weighted imaging ER -