Assessment of regional cerebral blood flow with 123I amphetamine single photon emission computed tomography in cerebrovascular disease. Semiquantitative analysis comparing IMP SPECT with the 133Xe inhalation method.

To compare the capacity of three-dimensional IMP single photon emission computed tomography (SPECT) with that of the two-dimensional 133Xe method in detecting focal perfusion abnormalities in cerebrovascular disease, flow measurements were performed with both methods in twenty patients. In order to enable correlation with 133Xe regional cerebral blood flow (rCBF) IMP SPECT images were subdivided into areas extending from the outer to the inner part corresponding to 32 regions of the 133Xe Cerebrograph. Between IMP counts/pixel and 133Xe rCBF, inter-hemispheric ratios correlated better in severe ischemia. Absolute mean values correlated in the affected hemisphere but not in the unaffected hemisphere. Regional evaluations revealed tendencies of IMP SPECT to be sensitive for low flow areas but to underestimate high flow areas, i. e. the 'luxury perfusion syndrome', as compared with the 133Xe method.