Abstract

As has been noted in the analysis of the symmetry of radiopharmaceutical (RPh) distribution between the cerebral hemispheres according to the data of a single-photon emission computed tomography (SPECT), there are quasi-symmetric regions of perfusion in the hemispheres. This study is focused on the investigation of this observation that eventually will lead to the development of new quantitative criteria of the brain functional state in terms of effective perfusion, and possibly will provide new knowledge on the structural and functional patterns of the brain. The authors develop a methodology for estimating intrahemispheric symmetry (IHS) of brain perfusion based on SPECT data. 32 SPECT images of patients with different levels of brain perfusion were analyzed. Scintigraphic investigations of the brain were conducted with _99mTc-HMPAO on the gamma camera E.Cam (Siemens) with LEHR collimator. The SPECT investigation was conducted 15–20 minutes after the RPh injection. The tomography study included the collection of 128 projections for 128×128 matrix; the injected RPh activity amounted to 740 mBq. The developed computerized standardization procedure of spatial orientation of brain SPECT image was implemented using the Scintybrain software in the Matlab 2018 environment. The main criterion for finding quasi-symmetric lines of brain perfusion profile is the cross-correlation coefficient r and the standard deviation between them. The number of selected pairs of profile lines depends on the predetermined threshold r_min. The analysis of experimental data shows that it is recommended to adopt the r_min value equal to 0.94 for quantifying the brain IHS. This paper presents a hypothesis of intrahemispheric quasi-symmetry of brain perfusion. The developed method of IHS analysis provides a new diagnostic information about the spatial RPh distribution and represents a fundamentally new tool for assessing the interrelationships of circulatory disorders of brain tissues in its various segments.

中文翻译：

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大脑灌注的半球内对称性。第 1 部分。计算程序

摘要

正如在根据单光子发射计算机断层扫描 (SPECT) 的数据对大脑半球之间放射性药物 (RPh) 分布的对称性分析中所指出的那样，半球中有准对称的灌注区域。这项研究的重点是对这一观察结果的调查，最终将导致在有效灌注方面开发新的大脑功能状态定量标准，并可能提供关于大脑结构和功能模式的新知识。作者开发了一种基于 SPECT 数据估计大脑灌注的半球内对称性 (IHS) 的方法。分析了 32 幅不同脑灌注水平患者的 SPECT 图像。大脑的闪烁扫描研究是用带有 LEHR 准直器的伽马相机 E.Cam（西门子）上的_99m Tc-HMPAO。SPECT 研究在 RPh 注射后 15-20 分钟进行。断层扫描研究包括为 128×128 矩阵收集 128 个投影；注入的 RPh 活性达到 740 mBq。在 Matlab 2018 环境中使用 Scintybrain 软件实现了开发的大脑 SPECT 图像空间定向的计算机化标准化程序。寻找脑灌注剖面准对称线的主要标准是互相关系数r和它们之间的标准偏差。所选择的轮廓线对的数量取决于预先确定的阈值r _min. 对实验数据的分析表明，建议采用等于 0.94的r _min值来量化大脑 IHS。本文提出了大脑灌注的半球内准对称假设。开发的 IHS 分析方法提供了关于空间 RPh 分布的新诊断信息，并代表了一种全新的工具，用于评估脑组织各个部分的循环障碍之间的相互关系。