AIMS AND OBJECTIVESTo study the pattern of brain involvement in acute hepatic encephalopathy in patients with chronic liver disease and correlate the extent of involvement on magnetic resonance imaging with serum ammonia and clinical severity. MATERIALS AND METHODSThirty patients with clinical or radiological evidence of chronic liver disease who presented with acute onset neuropsychiatric symptoms with a clinical diagnosis of acute hepatic encephalopathy. A detailed history was taken. Status of chronic liver disease confirmed, serum ammonia values estimated and magnetic resonance imaging done within 7 days of admission. The anatomic pattern of involvement in FLAIR and DWI (comparison with ADC maps) noted. The initial clinical severity (assessed by West Haven grade) and serum ammonia values were recorded and correlated with extent of involvement in magnetic resonance imaging. The patients were followed up for 21 days from the day of MRI to get an idea about inpatient or outpatient status; however, no clinical or radiological end points were evaluated. OBSERVATION AND RESULTSOn FLAIR and DWI, there were abnormalities in PLIC (73.3%, 60%), thalamus (63.3%, 53.3%), PVWM (26.7%, 16.7%) and IC (36.7%, 23.3%). There was significant correlation (P<0.05) for PVWM (P=0.001, 0.002) and IC (P=0.005, 0.009) involvement with clinical severity on FLAIR and DWI. There was no significant correlation for PLIC (P=0.371, 0.162) and thalamic (P=0.252, 0.92) involvement. All the patients showed elevated serum ammonia values and a period of inpatient stay >21 days. CONCLUSIONThe constellation of anatomic involvement in the appropriate clinical setting is suggestive of acute hepatic encephalopathy. Involvement of PVWM and IC indicated a higher grade of initial clinical severity.