[Reduction in mean cerebral blood flow measurements using 99mTc-ECD-SPECT during normal aging].

Mean cerebral blood flow (mCBF) was measured by SPECT using the 99mTc-ECD-Patlak-Plot method in a selected group of 61 normal non-hospitalized subjects aged 51 to 91 years. The mCBF values showed 48.4 +/- 4.7 ml/100 g/min in aged 50-59 years group, 49.9 +/- 5.9 ml/100 g/min in aged 60-69 years group, 46.4 +/- 6.5 ml/100 g/min in aged 70-79 group, 38.0 +/- 3.7 ml/100 g/min in aged 80-89 years group, 38.9 ml/100 g/min in aged 90-99 years group. There was a statistically significant reduction of mCBF with advancing age (R = -0.41; p = 0.001). Women have significantly higher mCBF values than men up to aged 70 years group. In this study, there was no significant laterality in the mCBF between right and left hemispheres in all decade groups. The history of hypertension, alcohol consumption, and cigarette smoking failed to show significant difference in the mCBF values. The present study shows that normal aging is associated with mCBF reduction.