轻微肝性脑病大脑结构与功能异常MRI表现

目的观察肝硬化(HC)继发轻微肝性脑病(MHE)患者大脑灰质结构和功能改变特征。方法对单纯HC患者30例(单纯HC组)、HC伴发MHE患者32例(MHE组)、健康对照34名(对照组)行神经心理学测试及结构与功能MR扫描,基于体素的形态学及局部一致性(ReHo)方法,分析大脑灰质结构和ReHo改变。结果 MHE组完成NCT-A时间较单纯HC组及对照组明显增高,而MHE组DST评分明显降低(P均<0.001)。与对照组比较,MHE组灰质体积改变的区域和强度明显增加。尾状核与眶部额内侧回(MFG)体积缩小和丘脑增大仅见于MHE组。双侧丘脑ReHo降低仅见于单纯HC组,双侧辅助运动区(SMA)、内侧额上回(SFG)及前扣带回(ACC)ReHo显著降低主要见于MHE组。单纯HC和MHE组丘脑体积与平均ReHo值呈正相关(r=0.342,P=0.007)。MHE组丘脑体积与眶部MFG体积改变呈正相关(r=0.448,P=0.01);SMA、ACC及内侧SFG平均ReHo值与NCT-A完成时间呈负相关(r=-0.529、-0.414、-0.450,P均<0.05),与DST评分呈正相关(r=0.562、0.483、0.459,P均<0.05)。结论联合结构与功能MRI研究可能为MHE诊断和发病机制提供更可靠的客观依据,丘脑、尾状核、额叶及扣带回体积与ReHo改变可能是MHE大脑结构与功能损伤的MRI影像特征。

MRI characteristics of structural and functional brain abnormalities in minimal hepatic encephalopathy

Objective To observe the characteristics of structural and functional brain abnormalities in hepatic cirrhosis (HC) with minimal hepatic encephalopathy (MHE) patients. Methods Thirty simple HE patients (simple HC group), 32 HC with MHE patients (MHE group)and 34 healthy controls (NC group) were enrolled. All subjects underwent neuropsychological tests and structural and functional MR scanning. The analysis of voxel-based morphometry (VBM) and regional homogeneity (ReHo) were performed to detect the alterations in brain structure and function. Results The times of number connection test type A (NCT-A) was significantly longer in MHE group than those in simple HC group and NC group, but the scores of digit symbol test (DST) were lowest in MHE group (all P<0.001). The extent and regions of brain gray matter volume changes were aggravated with the episodes of MHE, Increased volume of bilateral thalami and decreased volume of medial frontal gurus (MFG) were only found in MHE group. Significantly decreased ReHo of bilateral thalamus was only found in simple HC group. And significantly decreased ReHo of bilateral supplemental motor area (SMA), superior frontal gyrus (SFG) and anterior cingulate cortex (ACC) were mainly found in MHE group. Significant positive correlation between ReHo values and thalamus volume alterations was found in the combined HC and MHE groups (r=0.342, P=0.007). And positive correlation between thalamus volume alterations and MFG volume alterations was found in MHE group (r=0.448, P=0.01). Moreover, the ReHo values of SMA, ACC and SFG negatively correlated with the NCT-A times (r=-0.529, -0.414, -0.450, all P<0.05) and positively correlated with the DST scores (r=0.562, 0.483, 0.459, all P<0.05). Conclusion Brain structure and function MR study provide more reliable scientific basis for the diagnosis and mechanisms exploration of MHE. Abnormal brain volume and ReHo were found in thalamus, caudate, frontal lobe and anterior cingulate gyrus, which may be MRI characteristics of structural and functional brain impairments in MHE.