Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1721, USA.
J Magn Reson Imaging. 2009 Nov;30(5):1034-41. doi: 10.1002/jmri.21943.
To evaluate T(2)-relaxation changes in patients with minimal hepatic encephalopathy (MHE) using T(2) relaxometry and to correlate T(2) values with brain metabolites evaluated using 2D magnetic resonance spectroscopy (MRS).
Eight MHE patients and 13 healthy subjects were evaluated using T(2) relaxometry, and eight patients and nine healthy subjects underwent 2D MRS in right frontal and left occipital regions. Whole-brain T(2)-relaxation maps were compared between MHE and control subjects using analysis-of-covariance, with age and gender included as covariates. T(2) values derived from the right frontal and left occipital lobes were correlated with the metabolite ratios.
Multiple brain regions including anterior and mid cingulate cortices, right anterior and left posterior insular cortices, right prefrontal, medial frontal, and right superior temporal cortices showed significantly increased T(2) values in MHE patients compared to control subjects. MRS showed significantly increased ratios of glutamine/glutamate (Glx) and decreased ratios of myo-inositol, taurine, choline, and myo-inositol/choline (mICh) with respect to creatine (Cr_d) in patients compared to controls. Frontal Glx/Cr_d showed significantly positive correlation with T(2) values.
MHE patients showed significantly increased T(2) values in multiple brain regions reflecting increased free water content and T(2) values in frontal lobe correlated with the increased Glx/Cr_d ratio.
使用 T2 弛豫度测量法评估轻微型肝性脑病（MHE）患者的 T2 弛豫变化，并将 T2 值与二维磁共振波谱（MRS）评估的脑代谢物相关联。
对 8 例 MHE 患者和 13 例健康对照者进行 T2 弛豫度测量，对 8 例患者和 9 例健康对照者进行右侧额部和左侧枕部 2D MRS。采用协方差分析比较 MHE 患者与对照组之间的全脑 T2-弛豫图，将年龄和性别作为协变量。对右侧额部和左侧枕部 T2 值与代谢物比值进行相关性分析。
包括前扣带回皮质和中扣带回皮质、右侧额极和左侧岛叶皮质、右侧前额叶、内侧额叶和右侧颞上叶在内的多个脑区在 MHE 患者中 T2 值明显高于对照组。MRS 显示，与对照组相比，患者的谷氨酰胺/谷氨酸（Glx）比值显著升高，肌醇、牛磺酸、胆碱和肌醇/胆碱（mICh）与肌酸（Cr_d）比值降低。与对照组相比，患者的额部 Glx/Cr_d 比值与 T2 值呈显著正相关。
MHE 患者多个脑区的 T2 值明显升高，反映出自由水含量增加，额叶的 T2 值与 Glx/Cr_d 比值的升高呈正相关。
