Regional cerebral blood flow pattern in normal young and aged volunteers: a99mTc-HMPAO SPET study

Abstract

The aim of this study was to investigate the normal pattern of regional cerebral blood flow (rCBF) distribution in normal young and aged volunteers using technetium-99m hexamethylpropylene amine oxime (99m-Tc-HMPAO) as a tracer. The region brain perfusion of young and aged subjects was compared, especially regarding rCBF differences due to age and gender, and interhemispheric rCBF asymmetries. Sixty-eight right-handed normal volunteers - 40 young (mean age 29. 5+/-6.3 years) and 28 aged (mean age 71.2+/-4.3 years) - were included in the study. rCBF was estimated on the basis of a semiquantitative approach by means of a left/right index and two region/reference ratios, using the cerebellum and the whole brain activity as references. A good correlation between these two region/reference ratios was found (P<0.005 in all cerebral regions). The highest rCBF ratios corresponded to the cerebellum, followed by the occipital lobe. The remaining cortical regions (temporal, parietal, frontal and basal ganglia) showed slightly lower values. The white matter showed rCBF ratios substantially lower than the grey matter. In neither young nor aged subjects were significant rCBF differences between the genders found in any of the two region/reference indices employed. Aged subjects showed significantly lower rCBF ratios than young subjects in the left frontal lobe and in the posterior region of the left temporal lobe. In both young and aged subjects, lower perfusion was found in the left hemisphere, except for the white matter region in both age groups and the frontal lobe in the young subjects. Aged subjects presented a slightly higher interhemispheric asymmetry in the frontal lobe. However, interhemispheric asymmetry was minimal (-1. 01% to 3.14%). Consequently, a symmetrical rCBF distribution can be assumed between homologous regions, independent of age.

Asymmetric regional cerebral blood flow in sedated baboons measured by positron emission tomography (PET)

“…Reports of physiological asymmetries in humans during the resting state have been mixed, with many studies finding no evidence for left-right differences (Catafau et al, 1996;Moeller et al, 1996;Murphy et al, 1996;Seitz and Roland, 1992;Younkin et al, 1988). We have summarized the results of those studies that do report significant baseline physiological asymmetries in Table 5.…”

“…However, assessments of physiological asymmetries during a baseline, healthy state in humans have produced conflicting results. While some researchers have reported left-right asymmetries of cerebral blood flow or glucose metabolism in the resting state (Devous et al, 1986;Gur et al, 1995;Hagstadius and Risberg, 1989;Kolbitsch et al, 2000;Krausz et al, 1998;Perlmutter et al, 1985;Podreka et al, 1989;Rodriguez et al, 1991;Rootwelt et al, 1986;Tanaka et al, 2000;Van Laere et al, 2001a,b), many have failed to detect significant asymmetries (Catafau et al, 1996;Moeller et al, 1996;Murphy et al, 1996;Seitz and Roland, 1992;Younkin et al, 1988). The purpose of this study was to test for the presence of asymmetries of regional cerebral blood flow (rCBF) in baboons.…”

Cerebellar Hypoperfusion in Migraine Attack: Incidence and Significance

“…However, in healthy volunteers, interhemispheric asymmetry is minimal (1.01%-3.14%) and symmetric rCBF distribution can be assumed between homologous regions, independent of age. 35 Thus, our ROI-based semiquantitative analysis with the rather strict threshold of Ͼ10%, as commonly used in stroke or epilepsy studies, may be considered appropriate to balance measurements of random asymmetry and spreading oligemia. [22][23][24] Finally, all patients were symptom-free during follow-up.…”

Statistical Parametric Mapping Demonstrates Asymmetric Uptake with Tc-99m ECD and Tc-99m HMPAO SPECT in Normal Brain

“…Prior studies investigating lateral asymmetry in SPECT images of normal brain have used visual comparison (Aubert-Broche et al, 2005), manually placed or drawn region of interest (ROI) measurements (Markus et al, 1993;Catafau et al, 1996;Baird et al, 1999;Grova et al, 2003;Aubert-Broche et al, 2005), template-based ROI measurements (Krausz et al, 1998;Van Laere et al, 2001) or a two-compartment model (Risberg et al, 1975) to assess asymmetry. Prior studies have not, however, provided a comprehensive picture of the patterns of SPECT asymmetry.…”