Cerebral abnormalities in patients with cirrhosis detected by proton magnetic resonance spectroscopy and magnetic resonance imaging

Abstract

Hepatic encephalopathy is a common problem in cirrhosis. The pathogenesis of this complication of advanced liver disease still remains unclear. Magnetic resonance spectroscopy was used to assess prospectively cerebral metabolism in 51 patients with histologically proven cirrhosis (Child-Pugh classes A, B, and C, 18, 18, and 15, respectively) and 36 healthy volunteers. According to the results of psychometric tests, overt hepatic encephalopathy, subclinical encephalopathy, and no encephalopathy were found in 14, 21, and 16 patients, respectively. Myoinositol/creatine ratios in gray (.36 +/- .17) and white (.35 +/- .22) matter voxel were reduced significantly (P < .0001) in cirrhotic patients compared with healthy volunteers (gray matter, .51 +/- .11; white matter, .64 +/- .16). In addition, patients showed a significant reduction (P = .024) in white matter choline/creatine ratio (.77 +/- .27) compared with controls (.92 +/- .25), and glutamine/glutamate level was elevated in cirrhotic patients compared with controls (gray matter, P < .0001; white matter, P = .036). Changes in cerebral myoinositol and glutamine/glutamate levels correlated significantly with the severity of hepatic encephalopathy (P < .0001). However, these metabolic alterations were also detected in patients without hepatic encephalopathy (normal psychometric test results). N-acetyl aspartate/creatine ratios did not differ between patients and controls. Magnetic resonance imaging detected bright basal ganglia in 37 patients, which correlated significantly with portal-systemic shunting and elevation of glutamine/glutamate, but not with the degree of hepatic encephalopathy. In conclusion, magnetic resonance imaging and spectroscopy showed that alterations of cerebral metabolism are common in patients with cirrhosis, even without evidence of clinical or subclinical hepatic encephalopathy.

Brain MR Imaging and1H-MR Spectroscopy Changes in Patients with Extrahepatic Portal Vein Obstruction from Early Childhood to Adulthood

“…13,21 A similar reduction in myoinositol has been reported in adult EHPVO subjects. 4 However, in acute liver failure patients, no significant change in myo-inositol has been observed, indicating that there is insufficient time for osmolytes to compensate for significantly increased glutamine.…”

Liver and brain metabolism alterations in patients with minimal hepatic encephalopathy

“…Our study confirmed previous data showing a decrease of Mi/Cr and Mi/Cho ratios in patients with liver cirrhosis as compared to controls [12][13][14][15][16][17]. In astrocytes myo-inositol acts as an organic osmolyte, and is released from the cells in response to osmotic cell swelling [18].…”

MR Imaging Findings in Hepatic Encephalopathy

“…66 In patients with cirrhosis subjected to ammonia load, this mechanism of osmolar adaptation is clearly reflected in proton MR spectroscopy ( 1 H-MR spectroscopy) studies, which consistently show increases in the glutamine/ glutamate signal intensity accompanied by myo-inositol depletion and decreases in the choline signal intensity (Fig 2). [67][68][69][70][71][72][73] This osmoregulatory mechanism is activated after liver failure and accounts for the protection against massive edema in chronic liver failure. 74 The extent of the 1 H-MR spectroscopy alterations increases with increasing grade of HE, though these changes have also been observed in patients with cirrhosis and neither clinical nor psychometric or neurophysiologic signs of cerebral dysfunction.…”