神经影像对老年期痴呆鉴别诊断的应用研究

目的研究不同类型老年期痴呆患者的脑影像学特征，从而帮助临床进行鉴别诊断。方法：对104例阿尔茨海默病（AD）、130例血管性痴呆（vD）、62例额颞叶变性（FTLD）、37例路易体痴呆（DLB）、34例帕金森痴呆（PDD）、35例多系统萎缩（MSA）、1例克雅氏病（CJD）患者的临床资料进行回顾性分析，所有患者均行MRI平扫，部分患者行cT平扫，3例DLB患者行头氟18脱氧葡萄糖正电子发射断层扫描（18F-FDG PET）检查。结果：老年期痴呆在CT平扫中的表现差异较小。79％的AD患者表现为皮质萎缩，海马萎缩较明显；80％的VD患者有梗塞灶／出血灶，38％的患者表现为皮质萎缩、脑室扩大；58％的FTLD患者萎缩位于额叶和颞叶；约10％的DLB和PDD患者有轻度脑萎缩，或由于正常老化而产生的白质脱髓鞘；CJD在cT平扫上无特异性改变。MRI平扫中，各种老年期痴呆显像较清楚。89例（85．6％）AD患者有轻至重度海马萎缩，83例（79．8％）有颞顶叶萎缩；VD患者以大的梗死灶、出血灶、脑白质稀疏、腔隙性梗死、萎缩为主。AD患者主要为对称的皮层病变，海马及颞顶叶萎缩明显重于VD患者，而vD患者则以散在、不对称的皮层下病变为主，血管病变的发生率明显高于AD患者。FTLD患者表现为对称或不对称的局限性额叶及颞叶前部萎缩，而顶枕叶相对正常，此特征区别于广泛性脑萎缩，海马前端萎缩为主区别于AJ）的海马均一性萎缩。 37例DLB患者和34例PDD患者的MRI平扫均无特异性改变，海马结构无萎缩或与年龄相符的正常老化。MSA患者中29例（80．0％）有小脑萎缩和脑干变细，24例（68．6％）有脑桥十字征，10例（28．3％）有壳核裂隙征。1例CJD患者DWI像上可见左额颞顶枕皮层边缘的带状高信号。3例DLB患者的18F—FDG PET检查表现为枕叶及顶枕或颞顶枕联合区代谢减低。结论：老年期痴呆在cT平扫上显像不清，而MRI平扫对老年期痴呆的鉴别意义较大。PET—CT则可在疾病早期发现病理变化，在老年期痴呆的鉴别诊断上占据重要地位。

Objective：Research on brain imaging characteristics of different types of senile dementia,so as to help the clinical differential diagnosis of demen- tia.Methods：403 patients who were diagnosed as Alzheimer＇s disease （AD）, vascular dementia （VD）,frontotemporal lobar degeneration （FTLD）,dementia with Lewy bodies （DLB）,Parkinson disease with dementia （PDD）,multiple system atrophy （MSA）, Creutzfeldt Jakob disease （CJD）. All patients underwent MRI plain scan, some patients underwent CT plain scan.3 cases of DLB patients did head fluorine 18 fluorodeoxyglucose positron emission tomography （18F-FDG PET） check.Results：The performance difference of senile dementia in CT plain scan was small. CT plain scan,79% of AD patients showed cortical atrophy and hip- poeampus atrophy is more obvious; infarction or hemorrhage foci accounted for 80% in patients with VD,38% of VD patients performed for cortical atrophy and ventrieular dilatation; 58% of patients with FTLD patients had frontal and temporal lobes atrophy; about 10% of patients with DLB and PDD had mild brain atrophy,or white matter demyelination due to normal aging; The CJD patient on CT plain scan has no specific changes. All kinds of senile dementia pa- tients clear picture on MRI plain scan.89 eases （85.6%） of AD patients had mild to severe atrophy in the hippoeampus and 83 cases （79.8%） had tem- poroparietal lobe atrophy; VD patients had large infarction, hemorrhage, brain white matter rarefaction, lacunar infarction and atrophy as primary manifestation on MRI plain scan. AD patients had symmetric cortical lesions,hippocampus and temporoparietal lobe atrophy were more severe than that in the patients with VD, VD patients mainly had scattered, asymmetric subeortieal lesions, vascular lesions occurred rate was significantly higher than that of AD patients . FTLD pa- tients characterized by symmetrical or asymmetric localization of frontal lobe and anterior temporal lobe atrophy, while the oeeipitoparietal lobe was relatively normal. Frontal lobe and anterior temporal lobe atrophy of FTLD patients was different from that of AD generalized brain atrophy, and anterior temporal lobe a- trophy was mainly different from the AD of hippoeampus atrophy of homogeneity.MRI plain scan in 37 patients with DLB and 34 patients with PDD had no specific changes, no atrophy of hippoeampus formation or normal aging in conformity with age . 29 eases （80.0%） of MSA patients had cerebellum atrophy and brain stem thinning, 24 cases （68.6%） had the pontine cross sign, 10 cases （28.3%） had the putaminal slit syndrome. The CJD patient showed strip high signals on the left frontotemporal occipitoparietal cortex edge in DWI.18F-FDG PET examination in 3 eases of DLB patients showed hypometabolism of oceipi- tai lobe and oecipitoparietai oremperal oecipitoparietal association areas. Conclusion：Senile dementia is not clear on the CT plain scan, and MRI plain scan is sig- nificant for the identification of senile dementia. Diseases can be found in the early pathological changes in PET-CT, PET-CT occupy an important position in the differential diagnosis of senile dementia.