The Effect of Cerebral Infarction on the Regional Cerebral Blood Flow of the Contralateral Hemisphere

SUMMARY Xenon 133 inhalation CBF studies of one hundred patients with ischemic cerebrovascular disease in the territory of the carotid artery were compared in an attempt to gain more insight into the collateral capacity, especially in those with a stenosis or occlusion of one of the major arteries. Asymmetry of the ISI values for the two hemispheres was expressed as a ratio. High ratios (greater ISI asymmetries) were found for patients with an occlusion of the internal carotid or middle cerebral artery, especially -but not exclusively -those with the more severe clinical symptoms. It also appeared that even when the patient is in a good clinical condition, an elevated ratio reflects insufficiency of the collateral supply to the affected side. The ISI values for individual patients seem to be less useful, partly due to the variable age dependency of this flow parameter.

Section: Discussionmentioning

confidence: 99%

ISI values and interhemispheric differences in patients with ischemic cerebrovascular disease; correlations with clinical and angiographic findings.

Mosmans¹,

Veering²,

Jonkman³

1986

“…In contrast to absolute calculations, however, the relative approach requires comparison of each ROI with a "normal" reference region (usually within the contralateral hemisphere). The occurrence of perfusion disturbances in the contralateral hemisphere 36,37 makes the assumption that the contralateral hemisphere contains entirely normal tissue questionable. The latter constitutes a significant source of errors of relative perfusion measurements.…”

Section: Nabavi Et Al Perfusion Mapping Using Ct To Predict Cerebral mentioning

confidence: 99%

Perfusion Mapping Using Computed Tomography Allows Accurate Prediction of Cerebral Infarction in Experimental Brain Ischemia

Nabavi

Cenic

Henderson

et al. 2001

103

Background and Purpose-We have developed a dynamic CT method to measure absolute cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). In this study we evaluated the ability of CT-derived functional maps to detect infarction in a rabbit model of focal cerebral ischemia. Methods-Sequential dynamic CT studies were performed at 2 different slices in 5 control rabbits and another 8 after induction of focal cerebral ischemia. The size of critically ischemic tissue was correlated to size of infarction measured by postmortem 2,3,5-triphenyltetrazolium chloride staining. In the control rabbits, short-term variability of the parameters was assessed by ANOVA analysis. Results-In 7 of 8 animals of the ischemia group, cerebral infarction was visible on 2,3,5-triphenyltetrazolium chloride staining, constituting 16.7Ϯ10.6% of the ipsilateral hemisphere. Good agreement of CBF functional maps with tissue specimens was found with respect to size and location of infarction. Best prediction of infarction was found for thresholds of CBF Ͻ10 mL/100 g per minute (mean size, 17.5Ϯ13.4%; rϭ0.95) and MTT Ͼ6 seconds (mean size, 15.6Ϯ13.5%; rϭ0.85), with regression slopes close to unity. CBV maps were less predictive of occurrence of infarction, especially in cases of small infarction. The short-term variability of CBF, CBV, and MTT in the control group was 10.9%, 15.2%, and 19.9%, respectively. Conclusions-Functional

“…Some authors depend on cranial computed tomography (CT) and others on cerebral angiography to exclude patients with bilateral structural disease. 5 " 8 "~1 4 Since postmortem examination showed clinically unsuspected contralateral infarcts in some of these patients, 14 both techniques should be used to rule out bilateral infarcts and/or contralateral extracranial occlusive disease, either of which might explain the observed contralateral flow reduction. Prior studies also never controlled for other determinants of rCBF such as age, blood pressure, hematocrit, Pco 2 , and risk factors for stroke.…”

mentioning

confidence: 99%

Contralateral flow reduction in unilateral stroke: evidence for transhemispheric diaschisis.

Lagrèze¹,

Levine²,

Pedula³

et al. 1987

Using clinical presentation, angiography, computed tomography, and nuclear magnetic resonance imaging, 7 patients were identified who had strictly unilateral hemispheric infarction and unilateral cerebrovascular disease. In 6, cerebral blood flow measured by fluorine-18-fluoromethane inhalation and positron emission tomography was reduced in the contralateral hemisphere (p<0.05). Multiple regression analysis demonstrated a high correlation between contralateral flow reduction and the degree of flow impairment in the infarcted area (r = 0.941, p = 0.0014) but not with age, risk factor profile, blood pressure, Pco 2 , hematocrit, or duration of stroke. We conclude that transhemispheric diaschisis best explains the contralateral flow reduction seen in supratentorial ischemic stroke. (Stroke 1987;18:882-886)