Takahashi Kazuya, Ishiguro Masanobu, Inui Yoshitaka, Ichihara Takashi, Shang Cong, Nagao Ryunosuke, Mizutani Yasuaki, Ito Mizuki, Watanabe Hirohisa, Motomura Nobutoku, Toyama Hiroshi
Department of Radiology, Fujita Health University School of Medicine, Aichi, Japan.
Kazuya Takahashi and Masanobu Ishiguro contributed equally to this study.
Asia Ocean J Nucl Med Biol. 2025;13(1):33-41. doi: 10.22038/aojnmb.2024.78274.1557.
Sudden death in multiple system atrophy (MSA) is caused by decreased serotonergic innervation, but there is no routine test method for this decrease. In addition to dopamine transporters, iodine-123-labelled N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (I-FP-CIT) binds serotonin transporters (SERTs). We noted a binding potential to quantify the total quantity of I-FP-CIT binding to its receptors.Following Mintun's binding-potential concept, this study aimed to evaluate the relationship between the specific binding ratio (SBR) and total SERT tissue amount, but not SERT binding, and to develop an SBR imaging method to measure brain-stem SERT. We sought to establish a binding-potential imaging procedure using SBR images to examine differences in the brain-stem SERT distribution between healthy subjects and MSA patients.
Single-photon emission computed tomography (SPECT) and T1-weighted magnetic resonance (MR) images were aligned. The MR (T1) images were used to set a reference site for the occipital-lobe SBR in each subject, and measurements were made from the SPECT image at the same position. The pixel values and accumulation ratios compared with the occipital lobe were calculated, and a regional SBR distribution image was created. We identified areas with SERT accumulation above a certain level.
The SERT accumulation site was visualised as an SBR value on MR images. The accumulation distribution (SERT distribution) on the SBR images significantly differed between the healthy subjects and patients with MSA.
SERT accumulation was noted in the brain-stem region, indicating that SBR imaging was useful for viewing and quantifying SERT accumulation.
多系统萎缩（MSA）中的猝死是由血清素能神经支配减少所致，但对于这种减少尚无常规检测方法。除多巴胺转运体外，碘 - 123标记的N - （3 - 氟丙基） - 2β - 甲氧基羰基 - 3β - （4 - 碘苯基）去甲托烷（I - FP - CIT）可与血清素转运体（SERTs）结合。我们注意到一种结合潜能，可用于量化I - FP - CIT与其受体结合的总量。遵循明顿的结合潜能概念，本研究旨在评估特异性结合率（SBR）与SERT组织总量之间的关系，而非SERT结合情况，并开发一种SBR成像方法来测量脑干SERT。我们试图建立一种使用SBR图像的结合潜能成像程序，以检查健康受试者和MSA患者脑干SERT分布的差异。
将单光子发射计算机断层扫描（SPECT）和T1加权磁共振（MR）图像进行配准。利用MR（T1）图像为每个受试者的枕叶SBR设置一个参考位点，并在相同位置从SPECT图像进行测量。计算与枕叶相比的像素值和积聚率，并创建区域SBR分布图。我们确定了SERT积聚高于一定水平的区域。
SERT积聚部位在MR图像上表现为SBR值。健康受试者和MSA患者的SBR图像上的积聚分布（SERT分布）存在显著差异。
在脑干区域观察到SERT积聚，表明SBR成像有助于观察和量化SERT积聚。
