[The semiquantitative measurement method of cerebral blood flow using SPECT image].

I devised the convenient semiquantitative measurement method of cerebral blood flow using single photon emission computerized tomography (SPECT) and adapted clinically the method to vascular dementia. SPECT imaging utilized the tracer N-isopropyl-p-[I-123] iodo amphetamine (IMP) and 99mTc-hexamethyl-propyleneamineoxime (HMPAO) with a relative measure of regional tracer uptake normalized to cerebellar radiotracer uptake (rCBF ratios). In order to investigate relationships between dementia and cerebral blood flow, I studied 34 patients with vascular dementia and 20 control subjects by the semiquantitative measurements of relative regional cerebral blood flow (rCBF). In this study I set the lower most normal rCBF ratio (NFL) in IMP-SPECT and HMPAO-SPECT. These NFL of IMP-SPECT were higher than those NFL of HMPAO-SPECT in all cerebral cortices. NFL of IMP-SPECT were nearer to PET's than NFL of HMPAO-SPECT. I indicated rCBF ratio in each region of cerebrum by distinguishing color of SPECT image. In vascular dementia, while IMP-SPECT imaging showed the reduction of rCBF ratio in both of frontal lobes and temporal lobes, HMPAO-SPECT imaging indicated several groups which showed no reduction in temporal lobes. This difference may be due to the lower detection rate of ischemic change in HMPAO-SPECT than IMP-SPECT and it was consistent with many of other reports. This result may suggest usefulness of this method.