MEASUREMENT OF RADIOTRACER CONCENTRATION IN BRAIN GRAY-MATTER USING POSITRON EMISSION TOMOGRAPHY - MRI-BASED CORRECTION FOR PARTIAL VOLUME EFFECTS
MEASUREMENT OF RADIOTRACER CONCENTRATION IN BRAIN GRAY-MATTER USING POSITRON EMISSION TOMOGRAPHY - MRI-BASED CORRECTION FOR PARTIAL VOLUME EFFECTS
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DOI：
10.1038/jcbfm.1992.81
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发表时间：
1992-07-01
影响因子：
6.3
通讯作者：
FROST, JJ
中科院分区：
文献类型：
--
作者：
MULLERGARTNER, HW;LINKS, JM;FROST, JJ
正电子发射断层扫描(PET)在活体定量脑功能方面的准确性常常受到部分体积效应的限制。这一局限性在衰老和退行性脑疾病的研究中变得突出，其中部分体积效应随萎缩程度的不同而不同。本研究描述了如何使用将灰质(GM)的区域分数与部分体积效应相关联的算法来估计实际灰质(GM)示踪剂浓度。用磁共振成像(MRI)测定GM的区域分数。这一过程被指定为转基因PET。在计算机模拟和模体研究中，GM PET算法允许100%恢复新皮质GM和海马区的实际示踪剂浓度，而不考虑GM的体积。GMPET被应用于一例颞叶癫痫的测试病例中，发现在校正部分体积效应之前，在PET图像中没有检测到的GM中的放射性示踪剂活性增加。在计算机模拟中，GM分割的错误以及PET和MRI图像配准的错误导致GM PET图像的误差小于15%。总之，GMPET可以在活体内准确地测定人脑GM中的实际放射性示踪剂浓度。该方法区分表观放射性示踪剂浓度的变化是否仅反映GM体积的变化，或者更确切地说，反映单位GM体积的放射性示踪剂浓度的变化。
Accuracy in in vivo quantitation of brain function with positron emission tomography (PET) has often been limited by partial volume effects. This limitation becomes prominent in studies of aging and degenerative brain diseases where partial volume effects vary with different degrees of atrophy. The present study describes how the actual gray matter (GM) tracer concentration can be estimated using an algorithm that relates the regional fraction of GM to partial volume effects. The regional fraction of GM was determined by magnetic resonance imaging (MRI). The procedure is designated as GM PET. In computer simulations and phantom studies, the GM PET algorithm permitted a 100% recovery of the actual tracer concentration in neocortical GM and hippocampus, irrespective of the GM volume. GM PET was applied in a test case of temporal lobe epilepsy revealing an increase in radiotracer activity in GM that was undetected in the PET image before correction for partial volume effects. In computer simulations, errors in the segmentation of GM and errors in registration of PET and MRI images resulted in less than 15% inaccuracy in the GM PET image. In conclusion, GM PET permits accurate determination of the actual radiotracer concentration in human brain GM in vivo. The method differentiates whether a change in the apparent radiotracer concentration reflects solely an alteration in GM volume or rather a change in radiotracer concentration per unit volume of GM.