CLINICAL CORRELATION OF NEUROPSYCHOLOGICAL TESTS WITH H-1 MAGNETIC-RESONANCE SPECTROSCOPY IN HEPATIC-ENCEPHALOPATHY

Objective: The purpose of this project was to correlate neuropsycholog ical test results with in vivo measures of regional cerebral biochemis try determined by H-1 MRS in patients with subclinical and mild hepati c encephalopathy. Methods: Baseline H-1 MRS scans and neuropsychologic al testing of patients occurred at entry into the study. The primary l ocalized volume chosen for the H-1 MRS study was the posteromedial par ietal cortex, which consisted predominantly of white matter. Some of t hese patients were scanned again if they received a liver transplantat ion. In a subset: of patients, the effect on cerebral biochemistry and neuropsychological test performance due to a dietary intervention of reduced protein intake was monitored. These patients underwent a basel ine examination and a repeat examination after 2 weeks of dietary inte rvention. Measures were made of the correlation between the dietary in tervention and H-1 MRS determined biochemistry and the results of neur opsychological tests. Results in both patient groups (dietary interven tion and no dietary intervention) were compared with healthy control s ubjects. Results: Subclinical and low grade HE patients showed a signi ficant reduction in mI/Cr and Cho/Cr ratio when compared with healthy control subjects. These patients also showed impairment in frontal lob e mediated cognitive tasks and in motor ability that were not apprecia ted in a bedside examination. The patients did not return to normal ce rebral metabolic states within 30 to 60 days of liver transplantation. In fact, reductions remained in mI/Cr. Cho/Cr values increased after transplantation compared with healthy control subjects. Conclusions: H -1 MRS studies showed changes in regional cerebral biochemistry associ ated with all grades of IIE. There was a reduction in mI/Cr and a redu ction in Cho/Cr in patients with low grade and subclinical forms of HE compared with normal subjects. The reduction in mi correlated well wi th abnormalities observed in neuropsychological tests. Liver transplan tation was not associated with significant improvement in these variab les.