弥散张量成像在轻度认知功能障碍中的应用

Application of diffusion tensor imaging in mild cognitive impairment

轻度认知功能障碍(MCI)目前已经成为严重影响老年人健康的疾病,早期具有可逆性。近年来弥散张量成像(DTI)以其定量显示脑白质纤维束的优势,越来越多的应用于临床,成为了研究的热点。目前研究表明,MCI患者海马、穹隆、扣带回和胼胝体的DTI指标变化明显,可用于MCI的早期识别和病情评估及预测,且多个指标联用可能增加其准确性。MCI患者DTI表现与认知功能的下降程度具有相关性,尤其与记忆功能的相关性较为确定。MCI亚型中,遗忘型MCI(aMCI)发展为阿尔茨海默病(AD)的风险更高,其部分各向异性(FA)值越低、平均弥散度(ADC)值越高预示着转化为AD的可能性越大;DTI技术对AD与MCI患者脑白质的差异较为灵敏,AD的脑白质病变范围更广、程度更重。但目前关于DTI在MCI中的应用尚存在诸多问题,尚需进一步研究。

Mild cognitive impairment(MCI)has become a serious threat to the health of the elderly.It is reversible in early stage.In recent years,diffusion tensor imaging(DTI),a technique that can map white matter fibers quantitatively,has been increasingly applied in clinical practice and attracted much attention.Studies have shown that patients with MCI have significant changes in DTI parameters in the hippocampus,fornix,cingulate cortex,and corpus callosum,which can be used for the early identification,disease evaluation,and prognosis prediction of MCI,and the combination of multiple parameters may improve the accuracy.DTI findings are associated with the decline of cognitive function,especially memory,for patients with MCI.Among the subtypes of MCI,amnestic MCI has a high risk of developing into Alzheimer’s disease(AD),and the lower the fractional anisotropy and the higher the apparent diffusion coefficient,the greater the possibility of MCI progressing to AD.DTI shows good sensitivity in distinguishing the white matter between AD and MCI-AD has more extensive and severe white matter abnormalities.However,the application of DTI in MCI still faces many problems and needs further exploration.