Document Detail


MR imaging and HMPAO scintigraphy in conjunction with balloon test occlusion: value in predicting sequelae after permanent carotid occlusion.
MedLine Citation:
PMID:  1414776     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Permanent occlusion of the internal carotid artery may be required for en bloc resection of a neck tumor or to treat certain aneurysms. The risk of ischemic infarct is usually assessed with carotid balloon test occlusion and concurrent distal arterial pressure measurement. However, up to 20% of patients who tolerate the test occlusion have delayed neurologic sequelae. We propose enhanced MR imaging and hexamethylpropyleneamine oxime (HMPAO) scintigraphy to detect subclinical signs of ischemia and hypoperfusion as adjuncts to the balloon test occlusion to identify patients at risk for delayed sequelae. SUBJECTS AND METHODS: We prospectively examined 12 patients referred for balloon test occlusion of the carotid artery. Serial measurements of distal occluded internal carotid pressure were recorded. 99mTc-HMPAO was injected IV after 2 min of asymptomatic test occlusion, and single-photon emission computed tomographic (SPECT) data acquisition was done 1-6 hr later. Contrast-enhanced MR imaging was performed 1-8 hr after completion of the 30-min test occlusion. Signs of decreased perfusion or ischemia on these tests were compared with the mean distal arterial pressure and neurologic status of the patient during test occlusion. RESULTS: Seven (58%) of 12 patients had abnormal findings on HMPAO scintigraphy or contrast-enhanced MR imaging. Only one patient had neurologic deficits that corresponded to abnormal MR enhancement. The other 11 patients (92%) remained asymptomatic during the 30-min test occlusion. Of these 11 asymptomatic patients, five (45%) had areas of decreased perfusion on scintigraphy and three (27%) had abnormal MR contrast enhancement suggesting residual focal ischemia as a result of the test occlusion. Mean arterial pressures in the distal occluded artery did not correlate well with the imaging results. CONCLUSION: HMPAO scintigraphy can show clinically silent areas of decreased perfusion, while enhanced MR shows signs of acute ischemia (i.e., significant hypoperfusion) associated with asymptomatic balloon test occlusion. Theoretically, such patients would be at increased risk for permanent sequelae after permanent carotid occlusion.
Authors:
T M Simonson; T J Ryals; W T Yuh; G P Farrar; K Rezai; H T Hoffman
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  AJR. American journal of roentgenology     Volume:  159     ISSN:  0361-803X     ISO Abbreviation:  AJR Am J Roentgenol     Publication Date:  1992 Nov 
Date Detail:
Created Date:  1992-11-16     Completed Date:  1992-11-16     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  7708173     Medline TA:  AJR Am J Roentgenol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1063-8     Citation Subset:  AIM; IM    
Affiliation:
Department of Radiology, University of Iowa College of Medicine, Iowa City 52242.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Balloon Dilatation*
Brain / pathology,  radionuclide imaging
Brain Ischemia / diagnosis,  epidemiology*
Carotid Artery, Internal*
Cerebrovascular Circulation / physiology*
Collateral Circulation / physiology
Female
Head and Neck Neoplasms / surgery
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Organotechnetium Compounds / diagnostic use
Oximes / diagnostic use
Postoperative Complications / prevention & control
Prospective Studies
Risk Factors
Technetium Tc 99m Exametazime
Tomography, Emission-Computed, Single-Photon
Chemical
Reg. No./Substance:
0/Organotechnetium Compounds; 0/Oximes; 100504-35-6/Technetium Tc 99m Exametazime

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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