Cerebral 1H MR spectroscopy and neuropsychologic status of patients with hepatic encephalopathy.
OBJECTIVE
Our objective was to assess the metabolite levels (myo-inositol [ml], choline [Cho], creatine [Cr], glutamate or glutamine [Glx], and N-acetyl-L-aspartate [NAA]) visible on 1H MR spectroscopy in patients with subclinical and mild hepatic encephalopathy before and after liver transplantation and to correlate these data with the results of neuropsychiatric tests and related clinical findings.


METHODS
A stimulated-echo sequence was used to localize a single voxel in the parietal region. Seventeen patients and 13 healthy volunteers were investigated. Nine of the 17 patients also were investigated after liver transplantation. A battery of neuropsychologic tests also was administered to patients to assess frontal, memory, and motor functions.


RESULTS
Before liver transplantation, significant reductions in mI:Cr (51%) and Cho:Cr (11%) and a significant increase in Glx:Cr (20%) were observed in patients compared with the respective ratios in healthy subjects. Patients also were significantly impaired on neuropsychologic tests measuring frontal and motor performance, but not memory. Impairment on the frontal index showed a significant correlation with mI:Cr levels; likewise, performance on the motor index showed a significant correlation with serum ammonia levels before transplantation. MR spectroscopy after liver transplantation showed changes in the metabolite ratios compared with the pretransplantation status. Even though the Glx:Cr ratios decreased after transplantation, the mI:Cr ratio remained lower than those of healthy subjects.


CONCLUSIONS
The relationship of changes in the metabolite ratios recorded from a voxel in the posteromedial parietal lobe to the neuropsychologic findings before and after liver transplantation is a major finding.
Department of Radiological Sciences, UCLA School of Medicine, University of California, Los Angeles 90095, USA.
M A
MA
Thomas
A
A
Huda
B
B
Guze
J
J
Curran
M
M
Bugbee
L
L
Fairbanks
Y
Y
Ke
T
T
Oshiro
P
P
Martin
F
F
Fawzy
D000328:Adult; D001921:Brain / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D006501:Hepatic Encephalopathy / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D016031:Liver Transplantation; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests