Regional Cerebral Blood Flow in Acute Stroke: Preliminary Experience With the ¹³³ Xenon Inhalation Method

Abstract

Regional Method• The ""Xenon inhalation method of measuring regional cerebral blood flow was applied in serial studies comprising 100 measurements in 57 cases of acute hemiparesis and hemiplegia presumed due to arterial occlusion. Satisfactory data for analysis were obtained in over 95% of the cases studied. Significant flow reductions in the ischemic hemisphere were demonstrated in the cases with more severe clinical disability. This study demonstrates the feasibility of applying this method for serial regional cerebral blood flow measurements in most cases of acute stroke. The expected clinical usefulness and limitations of the method are discussed.Additional Key Words papaverine hemiplegia arterial occlusion hypertension heparin hemiparesis• If the treatment of acute stroke is to be given a rational basis, and achieve a success comparable with that of myocardial infarction, a system must be developed with the essential capability of continuously monitoring or frequently measuring regional cerebral blood flow over a period of three or more days.The purpose of this paper is to report a preliminary experience with the 18J Xenon inhalation method, and to report the results of a feasibility study of the applicability of this method in often uncooperative acutely ill patients. In undertaking this study, a quantitative evaluation of the method itself was not intended, and new information about the pathophysiology of cerebral infarction was not expected. It will be seen that though the method is logistically formidable, its essential safety can facilitate study of critically ill patients. Provided its quantitative accuracy is confirmed in ongoing studies, some progress in the rational management of acute stroke can be hoped for.

Lack of evolution of the cerebral blood flow during clinical recovery of a stroke.

“…18 - 26 Rao and co-workers 26 observed in the most ischemic region in symptomatic hemisphere a CBF increase in patients who made significant clinical improvement during the first two weeks after occurence of maximum disability. However, a cerebral infarct was not clearly demonstrated in all cases and the population studied could also include TIA or RIND patients.…”

Regional Cerebral Blood Flow by 133 Xenon Inhalation

“…The routines used in our laboratory for the measurement of rCBF have recently been described by Rao et al 5 The patient inhaled 133 Xenon in a concentration of about 2 mCi per liter during one minute and the radiation was recorded by four scintillation detectors over frontal and parietal regions of both hemispheres. The expired air activity was recorded by an additional scintillation detector.…”

“…The usefulness of serial rCBF measurements in the treatment and care of patients with acute stroke has recently been discussed in a preliminary communication from our laboratory. 5 The purpose of the present paper is to discuss methodological difficulties involved in the bicompartmental analysis of short (ten minutes) Xenon inhalation curves 4 recorded from 11 patients with cerebrovascular disorders. A new index of rCBF, the Initial Slope Index (ISI) 6 -7 modified for the inhalation technique, will be used.…”

Changes in cerebral blood flow and recovery from acute stroke.

“…9 Another related rCBF to survival rate during 7 years in patients with strokes 1 to 6 months prior to study. 2 Olsen observed patients with postischemic hyperperfusion generally improved clinically but did not find absence of hyperemia to indicate poor prognosis.…”