ORIGINAL ARTICLES  ADVANCES IN RADIOIMMUNOIMAGING AND RADIOIMMUNOTHERAPY 

The Quarterly Journal of Nuclear Medicine and Molecular Imaging 2007 December;51(4):357-63

Copyright © 2007 EDIZIONI MINERVA MEDICA

lingua: Inglese

99mTc-HMPAO and 99mTc-ECD brain uptake correlates of verbal memory in Alzheimer’s disease

Nobili F. ^{1, 2}, Koulibaly P. M. ³, Rodriguez G. ^{1, 2}, Benoit M. ⁴, Girtler N. ^{1, 2}, Robert P. H. ⁴, Brugnolo A. ^{1, 2}, Darcourt J. ³

¹ Clinical Neurophysiology S. Martino General Hospital, Genoa, Italy 2 Department of Endocrinological and Metabolic Sciences University of Genoa, Genoa, Italy 3 Nuclear Medicine Department Centre Antoine Lacassagne TIRO Laboratory CEA-University of Nice Sophia Antipolis, Nice, France 4 Memory Center, Federation of Clinical Neuroscience CHU-University of Nice Sophia Antipolis, Nice, France

Aim. Technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) and technetium-99m N,N-1,2-ethylene diylbis-Lcysteine diethyl ester dihydrochloride (99mTc-ECD) SPECT are widely used in Dementia Clinics for early and differential diagnosis. They have been shown to perform differently in Alzheimer’s disease (AD), but the impact of such differences on both research and clinical work is unknown. We investigated the differences between the 2 compounds in research work by assessing correlation between performance on a verbal memory task and cerebral perfusion in 2 matched groups of AD patients.
Methods. Nineteen pairs of patients with mild to moderate AD undergoing SPECT with either 99mTc-HMPAO or 99mTc-ECD were retrospectively selected in a Memory Clinic. Patients were matched for sex, age (±3 years) and the Mini-Mental State Examination score (±2 points) with a case-control procedure, thus obtaining 2 well-matched groups. The score on the Grober-Buschke selective reminding test (SRT) was correlated with SPECT in each group by means of statistical parametric mapping 99 (height threshold: P<0.01).
Results. 99mTc-HMPAO SPECT yielded 3 significant correlation clusters involving inferior and middle frontal gyri, para-hippocampal gyrus and putamen in the right hemisphere; the middle and superior temporal gyri, insula and claustrum in the left hemisphere. 99mTc-ECD gave a significant cluster of correlation in left postcentral gyrus and inferior parietal lobule.
Conclusion. 99mTc-HMPAO SPECT correlation sites seem more consistent than 99mTc-ECD ones with the neurophysiological models of verbal memory, as designed both in normal individuals and in pathological conditions. The demonstration of such relevant differences introduces a source of variability among studies performed with either of the 2 compounds, which must be considered when interpreting results.