Effects of aging on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime in healthy humans
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Some brain functions decline at a linear rate throughout adulthood. Others remain relatively stable until very late in the life cycle. This study characterized the effects of aging on the regional cerebral distribution of hexamethylpropylene amine oxime (HMPAO) in healthy human volunteers. The sample consisted of 26 men and 18 women with a mean age of 41.6±14.9 years (range: 19–73). Their past medical histories, physical examinations, and laboratory screening tests were normal. Single-photon emission tomography (SPET) scans of the brain were performed with a standardized acquisition and processing protocol on a triple-headed camera equipped with fan beam collimators. A 3-D restorative filter and a correction for uniform attenuation were applied before the images were reinterpolated in planes parallel to the line connecting the frontal and occipital poles. Mean counts per pixel were measured in multiple regions of interest (ROIs) within each hemisphere by custom fitting a set of templates to the images. The mean activity in each ROI was compared with the mean activity per pixel in the whole brain. Regression analyses were used to relate the activity ratios to age with both linear and nonlinear models. The relative concentration of radioactivity decreased significantly with age in most, but not all, gray matter structures. It increased in the white matter regions. The nonlinear model of aging fit the data significantly better than a straight line did. Most of the changes with age occurred during young adulthood. No further changes were detectable after the onset of middle age. The median breakpoint age at which the rate of change became negligible was 36.6 years. Aging significantly affects the relative uptake of HMPAO in healthy humans. It decreases in many gray matter regions and increases in most white matter regions. However, the changes do not appear to be linear. Most seem to occur during young adulthood before people reach their late thirties. The distribution then appears to remain relatively stable throughout middle age.
Key wordsAging Regional cerebral blood flow Single-photon emission tomography
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- 2.Lezak MD. Neuropsychological assessment, 2nd edn. New York: Oxford University Press, 1983.Google Scholar
- 4.Harley JP, Leuthold CA, Matthews CG, Bergs LE.Wisconsin Neuropsychological Test Battery T-score norms for older Veterans Administration Medical Center patients. Madison, Wis.: CG Matthews, 1980.Google Scholar
- 5.Heaton RK, Grant I, Matthews CG. Differences in neuropsychological test performance associated with age, education, and sex. In: Grant I, Adams KM, eds.Neuropsychological assessment of neuropsychiatric disorders. New York: Oxford University Press; 1986: 100–120Google Scholar
- 6.Heaton RK, Grant I, Matthews CG.Comprehensive norms for an expanded Halstead-Reitan Battery. Odessa, Fl.: Psychological Assessment Resources, Inc.; 1991: 5–13.Google Scholar
- 16.Inugami A, Kanno I, Uemura K, Shishido F, Mrakami M, Tmura N, Fujita H, Higano S. Linearization correction of99mTc-d,l-hexamethylene-propylene oxime (HM-PAO) image in terms of regional CBF distribution: comparison to C15O2 inhalation steady-state method measured by positron emission tomography.J Cereb Bloow Flow Metab 1988; 8 Suppl 1: S52-S60.Google Scholar
- 17.Yonekura Y, Nishizawa S, Mukai T, Fujita T, Fukuyama H, Ishikawa M, Kikuchi H, Konishi J, Andersen AR, Lassen NA. SPECT with 99mTc-d,l-hexamethylene-propylene oxime (HM-PAO) compared with regional cerebral blood flow measured by PET: effects of linearization.J Cereb Blood Flow Metab 1988; 8 Suppl 1: S52-S60.PubMedGoogle Scholar
- 21.Nishizawa S, Yonekura Y, Fujita T, Senda M, Mukai T, Saji H, Shibata T, Yamamoto K, Tamaki N, Fukuyama H, Harada K, Ishikawa M, Torizuka K. Brain perfusion SPECT with technetium-99m HM-PAO: comparative study with I-123 IMP and CBF measured by PET.J Nucl Med 1987; 28: 569.Google Scholar
- 27.Kuwabara Y, Ichiya Y, Sasake M, Akashi Y, Yoshida T, Fukumura T, Masuda K. Cerebellar vascular response to acetazolamide in crossed cerebellar diaschisis: a comparison of99mTc-HMPAO single-photon emission tomography with15O-H2O positron emission tomography.Eur J Nucl Med 1996; 23: 683–689.PubMedGoogle Scholar
- 28.Koyama M, Kawashima R, Ito H, Ono S, Sato K, Goto R, Kinomura S, Yoshioka S, Sato T, Fukuda H. SPECT imaging of normal subjects with technetium-99m-HMPAO and technetium-99m-ECD.J Nucl Med 1997; 587–592.Google Scholar
- 31.Som P, Oster ZH, Yamamoto K, Meinken GE, Srivastava SC, Yonekura Y, Ebner SA, Atkins HL, Brill AB, Fawwaz RA, Alderson PO, Coffey J, Carlton E, Hubner KF. Some factors affecting the cerebral and extracerebral accumulation ofN-isopropyl-p-iodo-amphetamine (IMP).Int J Nucl Med Biol 1985; 12: 185–196.PubMedGoogle Scholar