The validation and the limits of SPECT for patients suffering from cerebrovascular accidents

Contemporaneous single photon emission computed tomography (SPECT) and positron emission tomography (PET) were performed in 10 patients with cerebrovascular accidents (CVA), whose ages ranged from 11 to 67 years. I-123-isopropyl-iodoamphetamine (IMP) and/or Tc-99m hexamethylpropyleneamine oxime (HM-PAO) were used for SPECT. Cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate for oxygen (CMRO2) were measured by an O-15 labelled gas continuous-inhalation method. SPECT images were quite similar to CBF and CMRO2 during the chronic stage of CVA. Two patietns with vasospasm during the subacute stage had apparently low CBF and CMRO2 on PET, but did not have low perfusion on SPECT. Luxury perfusion areas were detected in 4 subacute stage patients and one chronic stage patient. A redistribution of IMP was detected in two patients with infarction during subacute stage. CMRO2 value in such an area was 2.0 ml/100 g/min. Low CBF and/or CMRO2 areas were well visualized by IMP rather than by HM-PAO SPECT. (N.K.)