Gupta R K, Dhiman R K
MR Section, Department of Radiodiagnosis, Sanjay Gandhi PGIMS, Lucknow 226 014.
Indian J Gastroenterol. 2003 Dec;22 Suppl 2:S45-9.
Hepatic encephalopathy (HE) is a potentially reversible neuropsychiatric syndrome secondary to cirrhosis and other severe liver diseases. Magnetic resonance imaging (MRI) and MR spectroscopy (MRS) have been explored to provide new insight into the pathophysiology, diagnosis and treatment of HE. MRI shows brain atrophy especially in the frontal region. Globus pallidus, putamen and portions of the internal capsule appear hyperintense on T1-weighted images; this is likely to be due to deposition of manganese as a result of portosystemic shunting and liver dysfunction. MRS permits the detection and quantification of certain brain metabolites in vivo. There is decrease in myoinositol and choline concentrations and increase in glutamine concentrations. There is no change in n-acetyl-aspartate. Depletion of myoinositol is the most sensitive and specific spectroscopic marker in HE. Its loss is most likely a compensatory mechanism for the accumulation of glutamine. In conclusion, MRI and MRS examine different aspects of hepatocerebral disease.
肝性脑病（HE）是继发于肝硬化和其他严重肝脏疾病的一种潜在可逆性神经精神综合征。人们已对磁共振成像（MRI）和磁共振波谱（MRS）进行研究，以期为肝性脑病的病理生理学、诊断和治疗提供新的见解。MRI显示脑萎缩，尤其是额叶区域。苍白球、壳核和内囊部分在T1加权图像上呈高信号；这可能是由于门体分流和肝功能障碍导致锰沉积所致。MRS能够在体内检测和定量某些脑代谢物。肌醇和胆碱浓度降低，谷氨酰胺浓度升高。N-乙酰天门冬氨酸没有变化。肌醇耗竭是肝性脑病中最敏感和特异的波谱标志物。其减少很可能是谷氨酰胺积累的一种代偿机制。总之，MRI和MRS检查了肝脑疾病的不同方面。
