PET脑皮质分区法在AD诊断中的应用

目的：采用PET脑皮质分区法，在目视法基础上，结合脑皮质/小脑计数比值半定量分析对AD进行研究。方法：研究对象分为4组：正常对照组、轻、中、重度AD各15例。全部受检者行PET脑静态显像，经计算机处理获得横断面影像。在横断面影像上将脑皮质进行分区，即上额叶、中额叶、下额叶、上颞叶、中颞叶、下颞叶、上顶叶和下顶叶，双侧脑皮质共16个脑区。应用目视法观察各脑区的横断层影像，并将脑皮质各区放射性计数与小脑放射性计数相除，获得各脑区/小脑计数比值。结果：15例正常人可见大脑皮质各区放射性摄取呈双侧对称性均匀分布，并计算出了正常人各脑区计数比值。45例AD均可见脑内有放射性减低区。AD病人大脑皮质放射性减低区的范围随痴呆程度加重而扩大。轻度AD脑代谢比值仅在下顶叶和中颞叶与正常对照组有显著性差异；中度AD则扩大到上、下顶叶，上额叶和上、中颞叶；重度AD则整个脑区都有显著性差异。结论：脑皮质分区法对AD诊断较传统脑叶法更为精确，尤其对AD早期诊断更有意义。

A study on the diagnosis of Alzheimer's disease by cerebral region analysis in PET

Objective: Visual analysis and semiquantitative analysis of cerebral cortex/cerebellum radioactivity ratio are used to diagnose Alzheimer's disease by a new method of dividing the cerebral cortex. Methods: The study includes four groups: Fifteen normal subjects, 15 mild AD patients, 15 moderate AD patients and 15 severe AD patients. All participants received static PET scanning. In the transverse images, we divide the bilateral frontal?parietal and temporal lobes into 16 regions, that is superior frontal lobe, middle frontal lobe, inferior frontal lobe, superior temporal lobe, middle temporal lobe, inferior temporal lobe, superior parietal lobe and inferior parietal lobe. We first use visual analysis to recognize the metabolic abnormalities. Radioactivity ratio as a semiquantitative index were also used in 16 region of cerebral lobes to analyze the characteristics of AD. Results: Fifteen age-matched healthy volunteers show that the radioactivity of all regions are bilaterally symmetric. All 45 AD patients show abnormal radioactivity. The metabolic abnormality grows severer as degree of dementia increased. In mild AD, radioactivity ratio of inferior parietal lobe and middle temporal lobe show statistic significance. In moderate AD, radioactivity ratios of inferior parietal lobe, superior temporal lobe, middle temporal lobe and left superior frontal lobe show statistic significance. In severe AD, all parts show statistic significance. Conclusion: Using cerebral region analysis to diagnose AD is more precise than traditional cerebral lobe analysis especially in early diagnosis.