Metabolic rates in small brain nuclei determined by high-resolution PET.
Metabolic rates in small brain nuclei determined by high-resolution PET.
复制标题
通过高分辨率 PET 测定脑小核团的代谢率。
作者：
W. Heiss;Birgit Habedank;J. Klein;K. Herholz;K. Wienhard;M. Lenox;R. Nutt
未标记
通过PET识别大脑中的小核团受到传统扫描仪的空间分辨率的限制。新的探测器技术和高分辨率研究断层扫描仪（HRRT）的先进信号分析，提高了三维空间分辨率为2.2毫米，在足够的效率，并允许在小体积的示踪剂浓度的量化。
方法
在9名健康志愿者中，静脉注射370 MBq的（18）F-FDG后，研究了脑葡萄糖代谢，并使用立体定位和局部解剖信息，在共配准的MR图像上确定了脑的各种结构中确定了局部脑葡萄糖代谢率（rCMRGlc）。
结果
rCMRGlc值（以mumol/100 g/min计）在大脑皮层中较高（33.5 ± 2.98），基底神经节（尾状核32.6 ± 3.04，壳核40.2 ± 3.50），丘脑（36.6 +/- 4.72）和小脑（29.8 +/- 2.20），而大脑白色物质（12.3 +/- 1.45）低于以前报道的常规扫描仪。这导致皮质值与白质值的比率增加。基底额叶的各个核团（基底前脑21.4 +/- 3.19，丘脑核32.3 +/- 2.39），颞叶（杏仁体22.2 ± 1.74），海马（25.7 ± 2.11），间脑（外侧膝状体23.1 ± 3.33，内侧膝状体20.2 ± 2.87，丘脑底核25.2 ± 3.29），脑干（上级24.4 +/- 2.47，下丘31.4 +/- 3.63，红核31.0 +/- 3.10，黑质22.8 +/- 2.35）可被识别，并评估这些结构的代谢率。提高空间分辨率对量化代谢率的影响可以直接在不同代扫描仪上研究的少数情况下得到证明。
结论
HRRT空间分辨率的提高降低了脑代谢率定量中的部分容积效应，并提高了大型结构中rCMRGlc值的准确性。这是第一次，这种扫描仪已经允许确定参与各种神经退行性疾病的小核团的代谢率。
UNLABELLED
Identification of small nuclei in the brain by PET has been limited by the spatial resolution of conventional scanners. The new detector technology and advanced signal analysis of a high-resolution research tomograph (HRRT) has improved 3-dimensional spatial resolution to 2.2 mm at sufficient efficiency and permitted the quantification of tracer concentrations in small volumes.
METHODS
In 9 healthy volunteers, cerebral glucose metabolism was investigated after intravenous injection of 370 MBq of (18)F-FDG, and regional cerebral metabolic rates for glucose (rCMRGlc) were determined in various structures of the brain identified on coregistered MR images using stereotactic and topographic anatomic information.
RESULTS
rCMRGlc values (in mumol/100 g/min) were higher in the cerebral cortex (33.5 +/- 2.98), the basal ganglia (32.6 +/- 3.04 in the nucleus caudatus and 40.2 +/- 3.50 in the putamen), the thalamus (36.6 +/- 4.72), and the cerebellum (29.8 +/- 2.20) and were lower in the cerebral white matter (12.3 +/- 1.45) than those reported previously with conventional scanners. This resulted in an increased ratio of cortical values to white-matter values. Various nuclei in the basal frontal lobe (21.4 +/- 3.19 in the basal forebrain and 32.3 +/- 2.39 in the nucleus accumbens), the temporal lobe (22.2 +/- 1.74 in the corpus amygdalae), the hippocampus (25.7 +/- 2.11), the diencephalon (23.1 +/- 3.33 in the corpus geniculatum laterale, 20.2 +/- 2.87 in the corpus geniculatum mediale, and 25.2 +/- 3.29 in the nucleus subthalamicus), and the brain stem (24.4 +/- 2.47 in the colliculus superior, 31.4 +/- 3.63 in the colliculus inferior, 31.0 +/- 3.10 in the nucleus ruber, and 22.8 +/- 2.35 in the substantia nigra) could be identified, and the metabolic rate was assessed in these structures. The effect of improved spatial resolution on quantified metabolic rates could directly be demonstrated in a few cases investigated on scanners of different generations.
CONCLUSION
The improved spatial resolution of the HRRT decreased partial-volume effects in the quantification of metabolic rates in the brain and increased the accuracy of rCMRGlc values in large structures. For the first time, this scanner has permitted the determination of metabolic rates in small nuclei that are involved in various neurodegenerative disorders.