Larson K B, Perman W H, Perlmutter J S, Gado M H, Ollinger J M, Zierler K
Department of Neurology and Neurological Surgery (Neurology), Washington University School of Medicine, St. Louis, Missouri 63110.
J Theor Biol. 1994 Sep 7;170(1):1-14. doi: 10.1006/jtbi.1994.1164.
Measurement of regional cerebral blood flow in vivo has proved useful in the study of normal and diseased states in the brain. This circumstance has led to a variety of techniques for its quantitative determination and has continued to motivate the search for ever safer and more accurate methods of measurement. Recently, the use of nuclear magnetic resonance (NMR) in medical imaging has stimulated efforts to make it the basis for a non-invasive method of measuring flow in the brain. New advances in fast NMR imaging (MRI) provide data potentially amenable to analysis by tracer-kinetic methods. Such an analysis has not previously been available. In this paper we present theoretical results that may permit measurement of brain blood flow by NMR. The data interpreted by our model are those generated by a novel MRI protocol developed by Perman et al. (1992, Magn. Reson. Med. 28, 74-83; Radiology 185(P), Abstr. 154, 127) that is entirely compatible with existing routine MRI procedures. These data are fast dynamic NMR signals that reflect passage of an intravenously administered paramagnetic contrast agent serving as a plasma tracer. Our equations show how to use such data sequences to determine plasma mean transit time, plasma volume, and plasma and whole-blood flow in arbitrarily selected regions of interest in the brain. The theory accounts rigorously for recirculation of tracer to the imaged regions. Our analysis provides an explanation for the linear relationship observed experimentally by others between regional vascular volumes and time integrals of vascular-tracer residue curves, and shows that this relationship remains valid in the presence of tracer recirculation.
体内局部脑血流量的测量已被证明在研究大脑的正常和疾病状态中很有用。这种情况导致了多种用于其定量测定的技术，并继续推动人们寻找更安全、更准确的测量方法。最近，核磁共振（NMR）在医学成像中的应用激发了人们努力使其成为测量脑血流量的非侵入性方法的基础。快速核磁共振成像（MRI）的新进展提供了可能适合用示踪动力学方法进行分析的数据。以前尚未有过这样的分析。在本文中，我们给出了可能允许通过核磁共振测量脑血流量的理论结果。由我们的模型解释的数据是由Perman等人（1992年，《磁共振医学》28卷，74 - 83页；《放射学》185(P)，摘要154，127）开发的一种新颖的MRI协议生成的，该协议与现有的常规MRI程序完全兼容。这些数据是快速动态核磁共振信号，反映了静脉注射的用作血浆示踪剂的顺磁性造影剂的通过情况。我们的方程展示了如何使用这样的数据序列来确定血浆平均通过时间、血浆体积以及大脑中任意选定感兴趣区域的血浆和全血流量。该理论严格考虑了示踪剂再循环到成像区域的情况。我们的分析为其他人实验观察到的局部血管体积与血管示踪剂残留曲线的时间积分之间的线性关系提供了解释，并表明在存在示踪剂再循环的情况下这种关系仍然有效。
