Kawasaki Keiichi, Ishii Kenji, Saito Yoko, Oda Keiichi, Kimura Yuichi, Ishiwata Kiichi
Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo, Japan.
Ann Nucl Med. 2008 Apr;22(3):191-200. doi: 10.1007/s12149-007-0099-7. Epub 2008 May 23.
In clinical cerebral 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) studies, we sometimes encounter hyperglycemic patients with diabetes mellitus or patients who have not adhered to the fasting requirement. The objective of this study was to investigate the influence of mild hyperglycemia (plasma glucose range 110-160 mg/dl) on the cerebral FDG distribution patterns calculated by statistical parametric mapping (SPM).
We studied 19 healthy subjects (mean age 66.2 years). First, all the subjects underwent FDG-PET scans in the fasting condition. Then, 9 of the 19 subjects (mean age 64.3 years) underwent the second FDG-PET scans in the mild hyperglycemic condition. The alterations in the FDG-PET scans were investigated using SPM-and region of interest (ROI)-based analyses. We used three reference regions: (1) SPM global brain (SPMgb) used for SPM global mean calculation, (2) the gray and white matter region computed from magnetic resonance image (MRIgw), and (3) the cerebellar cortex (Cbll).
The FDG uptake calculated as the standardized uptake value (average) in SPMgb, MRIgw, and Cbll regions in the mild hyperglycemic condition was 42.7%, 41.3%, and 40.0%, respectively, of that observed in the fasting condition. In SPM analysis, the mild hyperglycemia was found to affect the cerebral distribution patterns of FDG. The FDG uptake was relatively decreased in the gray matter, mainly in the frontal, temporal, and parietal association cortices, posterior cingulate, and precuneus in both SPMgb-and MRIgw-reference-based analyses. When Cbll was adopted as the reference region, those decrease patterns disappeared. The FDG uptake was relatively increased in the white matter, mainly in the centrum semiovale in all the reference-based analyses.
It is noteworthy that the FDG distribution patterns were altered under mild hyperglycemia in SPM analysis. The decreased uptake patterns in SPMgb-(SPM default) and MRIgw-reference-based analyses resembled those observed in Alzheimer's disease. Under mild hyperglycemia, we can recommend Cbll as the reference region to detect decreased uptake patterns. We should pay special attention to controlling the diet condition, monitoring hyperglycemia, and optimizing the reference region in SPM analysis, particularly in the diagnosis of early Alzheimer's disease in clinical FDG-PET.
在临床脑部2-[(18)F]氟-2-脱氧-D-葡萄糖正电子发射断层扫描（FDG-PET）研究中，我们有时会遇到糖尿病高血糖患者或未遵守禁食要求的患者。本研究的目的是调查轻度高血糖（血浆葡萄糖范围为110 - 160 mg/dl）对通过统计参数映射（SPM）计算的脑部FDG分布模式的影响。
我们研究了19名健康受试者（平均年龄66.2岁）。首先，所有受试者在禁食状态下接受FDG-PET扫描。然后，19名受试者中的9名（平均年龄64.3岁）在轻度高血糖状态下接受第二次FDG-PET扫描。使用基于SPM和感兴趣区域（ROI）的分析来研究FDG-PET扫描的变化。我们使用了三个参考区域：（1）用于SPM全局平均值计算的SPM全脑（SPMgb），（2）根据磁共振图像（MRIgw）计算的灰质和白质区域，以及（3）小脑皮质（Cbll）。
在轻度高血糖状态下，SPMgb、MRIgw和Cbll区域中以标准化摄取值（平均值）计算的FDG摄取分别为禁食状态下观察值的42.7%、41.3%和40.0%。在SPM分析中，发现轻度高血糖会影响FDG的脑部分布模式。在基于SPMgb和MRIgw参考的分析中，灰质中的FDG摄取相对减少，主要在额叶、颞叶和顶叶联合皮质、后扣带回和楔前叶。当采用Cbll作为参考区域时，这些减少模式消失。在所有基于参考的分析中，白质中的FDG摄取相对增加，主要在半卵圆中心。
值得注意的是，在SPM分析中，轻度高血糖会改变FDG分布模式。基于SPMgb（SPM默认）和MRIgw参考的分析中摄取减少模式类似于在阿尔茨海默病中观察到的模式。在轻度高血糖情况下，我们建议使用Cbll作为参考区域来检测摄取减少模式。我们应特别注意控制饮食状况、监测高血糖以及在SPM分析中优化参考区域，特别是在临床FDG-PET早期阿尔茨海默病的诊断中。
