Investigation of Senile Dementia with PET and MRI

本研究试图从正常衰老到老年性痴呆的变化中提取特征。获得的结果如下。(1)脑代谢与MRI的增龄变化我们研究了PET脑血流量与MRI上的室周高信号（PVH）的关系，PVH是一种增龄变化，在重度PVH病例中发现脑血流量减少。(2)多发梗塞性痴呆（MID）的X线CT表现特征。脑萎缩随年龄增长而进展。我们发现，不像在正常老化的MID的情况下，侧脑室下角的特征性增宽。(3)本研究通过对Alzheimer型老年痴呆（SDAT）和MID的PET脑局部葡萄糖代谢的研究，初步探讨了具有相同临床症状但发病机制不同的SDAT和MID脑局部葡萄糖代谢功能改变的共同基础。我们从局部脑葡萄糖代谢的角度对这些功能异常进行了研究，发现痴呆患者的联合皮质普遍存在葡萄糖代谢低下。(4)侧脑室下角增宽与局部脑葡萄糖代谢降低的关系我们探讨了脑室系统的大小与局部脑葡萄糖代谢的关系。结果表明，无论痴呆类型是MID还是SDAT，侧脑室下角增宽均与大脑皮质局部糖代谢降低密切相关，提示痴呆与构成下角内侧的海马和杏仁核的改变密切相关。因此，我们在这里强调，边缘系统的研究作为一个重点，在痴呆症的调查是非常必要的。

In this research, we tried to extract the characters of changes from normal aging through senile dementia. The results obtained were as follows.(1) Cerebral metabolism and aging changes on MRI.We investigated the relationship between cerebral blood flow by PET and the periventricular hyperintensity (PVH) which is an aging change on MRI and found decreased cerebral blood flow in cases of severe PVH.(2) Characters of formal changes in multi-infarct dementia (MID) on X-CT.Brain atrophy progresses during aging. We revealed the characteristic widening of the inferior horns of the lateral ventricles in cases of MID unlike in normal aging.(3) Regional cerebral glucose metabolism on PET in senile dementia of Alzheimer type (SDAT) and MID.We assumed the common basis of functional changes in SDAT and MID which have different pathogenesis but have same clinical symptoms. We studied these functional abnormalities from the aspect of regional cerebral glucose metabolism and found common hypometabolism of glucose in the association corteces of dementia cases.(4) Correlation between widening of the inferior horns of the lateral ventricles and decrease of regional cerebral glucose metabolism.We investigated the relationship between the size of ventricular system and regional cerebral glucose metabolism. The results showed that widening of the inferior horns of the lateral ventricles was strongly correlated with decrease of regional cerebral glucose metabolism in cerebral corteces regardless of the type of dementia, MID or SDAT.These results suggested that dementia was closely related to the changes in hippocampus and amygdala which constitutes the medial aspect of the inferior horns. Therefore we emphasize here the great necessity for studies of the limbic system as a focus in the investigation of dementia.