Postcarotid Endarterectomy Improvement in Cognition Is Associated with Resolution of Crossed Cerebellar Hypoperfusion and Increase in  123 I-Iomazenil Uptake in the Cerebral Cortex: A SPECT Study

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Abstract

Background: The purpose of the present study was to investigate whether resolution of crossed cerebellar hypoperfusion (CCH) and increase in 123I-iomazenil (IMZ) uptake in the ipsilateral cerebral cortex after carotid endarterectomy (CEA) are associated with postoperative improvement of cognitive function. Methods: Neuropsychological testing was performed preoperatively and after 1 postoperative month in 79 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≧70%). Brain perfusion single photon emission computed tomography (SPECT) using N-isopropyl- p-123I-iodoamphetamine and 123I-IMZ SPECT were also performed before and after surgery. Data were analyzed using a three-dimensional stereotaxic region of interest template. Results: Seven patients (9%) showed improvement in postoperative cognitive function. All the 7 patients exhibited both postoperative increase in blood flow in the ipsilateral cerebral cortex and resolution of CCH. Five patients (6%) had a postoperative hemispheric increase in 123I-IMZ uptake, and cognitive function improved in all of these 5 patients. Analysis by a receiver operating characteristic (ROC) curve was used to estimate the ability to discriminate between patients with and without postoperative cognitive improvement. The area under the ROC curve was significantly greater when analyzing the magnitude of postoperative resolution of CCH (0.991; 95% CI 0.984–1.001) or postoperative hemispheric increase in 123I-IMZ uptake (0.981; 95% CI 0.972–0.999) when compared with the magnitude of postoperative increase in cerebral blood flow (0.929; 95% CI 0.886–0.971) (p < 0.05). Conclusions: Resolution of CCH and increase in 123I-IMZ uptake in the ipsilateral cerebral cortex after CEA is associated with postoperative improvement in cognitive function. These results may indicate that cognitive impairment is related to a state of potentially reversible central benzodiazepine receptor downregulation in the cortex in response to transient ischemic attack or minor stroke.

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Most cited references 14

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The relationship between global and local changes in PET scans.

K J Friston, R Frackowiak, Peter Liddle … (1990)

In order to localize cerebral cognitive or sensorimotor function, activation paradigms are being used in conjunction with PET measures of cerebral activity (e.g., rCBF). The changes in local cerebral activity have two components: a global, region independent change and a local or regional change. As the first step in localizing the regional effects of an activation, global variance must be removed by a normalization procedure. A simple normalization procedure is division of regional values by the whole brain mean. This requires the dependence of local activity on global activity to be one of simple proportionality. This is shown not to be the case. Furthermore, a systematic deviation from a proportional relationship across brain regions is demonstrated. Consequently, any normalization must be approached on a pixel-by-pixel basis by measuring the change in local activity and change in global activity. The changes associated with an activation can be partitioned into global and local effects according to two models: one assumes that the increase in local activity depends on global values and the other assumes independence. It is shown that the increase in activity due to a cognitive activation is independent of global activity. This independence of the (activation) condition effect and the confounding linear effect of global activity on observed local activity meet the requirements for an analysis of covariance, with the "nuisance" variable as global activity and the activation condition as the categorical independent variable. These conclusions are based on analysis of data from 24 scans: six conditions over four normal subjects using a verbal fluency paradigm.(ABSTRACT TRUNCATED AT 250 WORDS)

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Carotid endarterectomy--an evidence-based review: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

Timothy R Coté, , Stephen Hess … (2005)

To assess the efficacy of carotid endarterectomy for stroke prevention in asymptomatic and symptomatic patients with internal carotid artery stenosis. Additional clinical scenarios, such as use of endarterectomy combined with cardiac surgery, are also reviewed. The authors selected nine important clinical questions. A systematic search was performed for articles from 1990 (the year of the last statement) until 2001. Additional articles from 2002 through 2004 were included using prespecified criteria. Two reviewers also screened for other relevant articles from 2002 to 2004. Case reports, review articles, technical studies, and single surgeon case series were excluded. For several questions, high quality randomized clinical trials had been completed. Carotid endarterectomy reduces the stroke risk compared to medical therapy alone for patients with 70 to 99% symptomatic stenosis (16% absolute risk reduction at 5 years). There is a smaller benefit for patients with 50 to 69% symptomatic stenosis (absolute risk reduction 4.6% at 5 years). There is a small benefit for asymptomatic patients with 60 to 99% stenosis if the perioperative complication rate is low. Aspirin in a dose of 81 to 325 mg per day is preferred vs higher doses (650 to 1,300 mg per day) in patients undergoing endarterectomy. Evidence supports carotid endarterectomy for severe (70 to 99%) symptomatic stenosis (Level A). Endarterectomy is moderately useful for symptomatic patients with 50 to 69% stenosis (Level B) and not indicated for symptomatic patients with <50% stenosis (Level A). For asymptomatic patients with 60 to 99% stenosis, the benefit/risk ratio is smaller compared to symptomatic patients and individual decisions must be made. Endarterectomy can reduce the future stroke rate if the perioperative stroke/death rate is kept low (<3%) (Level A). Low dose aspirin (81 to 325 mg) is preferred for patients before and after carotid endarterectomy to reduce the rate of stroke, myocardial infarction, and death (Level A).

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Cerebral blood flow SPET in transient global amnesia with automated ROI analysis by 3DSRT.

Ryo Takeuchi, Yoshiharu Yonekura, K Yoshioka … (2004)

The aim of this study was to determine the areas involved in episodes of transient global amnesia (TGA) by calculation of cerebral blood flow (CBF) using 3DSRT, fully automated ROI analysis software which we recently developed. Technetium-99m L, L-ethyl cysteinate dimer single-photon emission tomography ((99m)Tc-ECD SPET) was performed during and after TGA attacks on eight patients (four men and four women; mean study interval, 34 days). The SPET images were anatomically standardized using SPM99 followed by quantification of 318 constant ROIs, grouped into 12 segments (callosomarginal, precentral, central, parietal, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus, hippocampus and cerebellum), in each hemisphere to calculate segmental CBF (sCBF) as the area-weighted mean value for each of the respective 12 segments based on the regional CBF in each ROI. Correlation of the intra- and post-episodic sCBF of each of the 12 segments of the eight patients was estimated by scatter-plot graphical analysis and Pearson's correlation test with Fisher's Z-transformation. For the control, (99m)Tc-ECD SPET was performed on eight subjects (three men and five women) and repeated within 1 month; the correlation between the first and second sCBF values of each of the 12 segments was evaluated in the same way as for patients with TGA. Excellent reproducibility between the two sCBF values was found in all 12 segments of the control subjects. However, a significant correlation between intra- and post-episodic sCBF was not shown in the thalamus or angular segments of TGA patients. The present study was preliminary, but at least suggested that thalamus and angular regions are closely involved in the symptoms of TGA.

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Author and article information

Journal

Journal ID (publisher-id): CED

Journal ID (nlm-ta): Cerebrovasc Dis

Journal ID (doi): 10.1159/issn.1015-9770

Title: Cerebrovascular Diseases

Publisher: S. Karger AG

ISSN (Print): 1015-9770

ISSN (Electronic): 1421-9786

Publication date Subscription-year: 2010

Publication date (Print): March 2010

Publication date (Electronic): 30 January 2010

Volume: 29

Issue: 4

Pages: 343-351

Affiliations

^aDepartment of Neurosurgery and ^bCyclotron Research Center, Iwate Medical University, Morioka, and ^cDepartment of Physical Therapy, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Japan

Article

Publisher ID: 278930 Other ID: Cerebrovasc Dis 2010;29:343–351

DOI: 10.1159/000278930

PubMed ID: 20130400

SO-VID: 43f515c5-5387-48fe-842d-e87a2a340a36

License:

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

History

Date received : 02 July 2009

Date accepted : 05 November 2009

Page count

Figures: 6, Tables: 1, References: 32, Pages: 9

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