Abstract
We performed quantitative measurements of cerebral blood flow (CBF) using 99mTc tracer by the Patlak Plot method with reference to normal aging and cerebrovascular reserve (CVR) capacity and then investigated a new evaluation method of CVR. Aging and decrease of ADL were significantly associated with reduction of the mean hemispheric CBF. In the acetazolamide (ACZ) stress test, these retrospective data showed some overlap in each ischemic grade on the relationship between rCBF and CVR response for the predictability of EC/IC bypass surgery. In these controversial problems, we must reconfirm the principle of cerebral hemodynamic perfusion in SPECT. First, retention tracer is distributed via the microcirculatory system to brain tissue. Second, therefore, we should understand not only the circulation of major vessels, but also the dynamics and rheology in parenchymal microcirculation to determine brain SPECT and CVR capacity. In the next step, we approached the new evaluation method of CVR capacity using 99mTc tracer by a serial dynamic SPECT with a slip-ring rotational gamma camera. These preliminally findings suggest that a serial dynamic SPECT may be more useful for analyzing the pathophysiology on brain circulation and CVR than conventional approaches.
