Murase K, Tanada S, Fujita H, Sakaki S, Hamamoto K
Deparment of Radiology and Neurosurgery, Ehime University School of Medicine, Japan.
J Nucl Med. 1992 Jan;33(1):135-43.
The kinetic behavior of 99mTc-hexamethylpropyleneamine oxime (HMPAO) in the human brain was investigated in 11 patients with various brain diseases (176 regions), using dynamic SPECT and a four-compartment model with five parameters (K1: rate constant for the transport of HMPAO from blood to brain, K2: backdiffusion from brain to blood, K3: conversion to a hydrophilic form in the brain, K5: conversion to a nondiffusible form in the blood, and fa: fraction of radioactivity attributable to the vascular compartment). Although K1 correlated well with cerebral blood flow (CBF) measured by the 133Xe inhalation method (Xe-CBF) (r = 0.888), its value was underestimated by 28.9% +/- 11.9%, indicating a low extraction fraction (E) for HMPAO. From E = K1/CBF, a regression equation of E = 0.857 - 0.00335. Xe-CBF was obtained. Significant correlations were observed for K2 versus Xe-CBF (r = 0.679), for K3 versus Xe-CBF (r = 0.483), for K3/(K2 + K3) versus Xe-CBF (r = -0.487), for K3/K2 versus Xe-CBF (r = -0.501), and for K2 + K3 versus Xe-CBF (r = 0.655), but not for K1/K2 versus Xe-CBF (r = 0.005). Thus, this model was useful for elucidating the kinetic behavior of HMPAO in the human brain, and correction for E appears to be indispensable for accurate CBF quantification using HMPAO.
采用动态单光子发射计算机断层扫描（SPECT）和具有五个参数的四室模型（K1：99m锝-六甲基丙烯胺肟（HMPAO）从血液到脑的转运速率常数；K2：从脑到血液的反向扩散；K3：在脑内转化为亲水性形式；K5：在血液中转化为非扩散性形式；fa：归因于血管腔室的放射性分数），对11例患有各种脑部疾病的患者（176个区域）的人脑内99mTc-HMPAO的动力学行为进行了研究。尽管K1与通过吸入133氙方法（Xe-CBF）测量的脑血流量（CBF）具有良好的相关性（r = 0.888），但其值被低估了28.9%±11.9%，表明HMPAO的提取分数（E）较低。根据E = K1/CBF，得到回归方程E = 0.857 - 0.00335·Xe-CBF。观察到K2与Xe-CBF之间存在显著相关性（r = 0.679），K3与Xe-CBF之间存在显著相关性（r = 0.483），K3/(K2 + K3)与Xe-CBF之间存在显著相关性（r = -0.487），K3/K2与Xe-CBF之间存在显著相关性（r = -0.501），以及K2 + K3与Xe-CBF之间存在显著相关性（r = 0.655），但K1/K2与Xe-CBF之间不存在显著相关性（r = 0.005）。因此，该模型有助于阐明HMPAO在人脑中的动力学行为，并且对于使用HMPAO进行准确的CBF定量而言，对E进行校正似乎是必不可少的。
