Document Detail

Alterations in regional cerebral blood flow, with increased temporal interhemispheric asymmetries, in the normal elderly: an HMPAO SPECT study.
MedLine Citation:
PMID:  8371888     Owner:  NLM     Status:  MEDLINE    
Single photon emission computed tomography (SPECT) with the tracer 99Tcm-hexamethylpropyleneamine oxime (HMPAO) provides images allowing semiquantitative estimation of regional cerebral blood flow (rCBF). Despite its widespread use there is little data on patterns of rCBF obtained using this tracer in normal elderly subjects, although other methods of measurement suggest a fall in cerebral blood flow with age. Furthermore, the detection of interhemispheric asymmetries on HMPAO SPECT is often used to identify areas of pathological abnormality yet there is little data on the prevalence of asymmetries in the normal elderly. An increased prevalence of asymmetries in the elderly may explain the difficulties recently reported in using functional imaging in the diagnosis of Alzheimer's dementia. Patterns of HMPAO uptake were compared in 10 young (mean age 24.9 years; range 21-34 years) and 10 elderly (mean age 74.1 years; range 70-76 years) normal subjects. Percentage interhemispheric asymmetry ratios were calculated and found to be greater in the elderly, particularly for the temporal cortex (young 0.87%, elderly 3.73%, P < 0.001). The proportion of injected HMPAO taken up by the head was 29% higher in the younger age group. Analysis of regional uptake revealed that this trend towards reduced uptake in the elderly was a global phenomenon affecting all brain regions. The increased interhemispheric asymmetries seen in the elderly imply that a higher threshold for interpreting asymmetries as abnormal must be used in the elderly, particularly for the temporal cortex.
H S Markus; H Ring; K Kouris; D C Costa
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Nuclear medicine communications     Volume:  14     ISSN:  0143-3636     ISO Abbreviation:  Nucl Med Commun     Publication Date:  1993 Aug 
Date Detail:
Created Date:  1993-10-14     Completed Date:  1993-10-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8201017     Medline TA:  Nucl Med Commun     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  628-33     Citation Subset:  IM    
Department of Neurology, University College and Middlesex Hospitals School of Medicine, London, UK.
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MeSH Terms
Brain / radionuclide imaging*
Cerebrovascular Circulation / physiology*
Organotechnetium Compounds / diagnostic use*
Oximes / diagnostic use*
Reference Values
Technetium Tc 99m Exametazime
Tomography, Emission-Computed, Single-Photon
Reg. No./Substance:
0/Organotechnetium Compounds; 0/Oximes; 100504-35-6/Technetium Tc 99m Exametazime

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