Early and delayed SPECT using N-isopropyl p-iodoamphetamine iodine 123 in cerebral ischemia. A prognostic index for clinical recovery.

Sixteen patients with stroke, five patients with permanent regressive ischemic neurologic deficit, and three patients with transient ischemic attacks were studied by single photon emission computed tomography performed within the first hour (early scan) and four hours (delayed scan) after injection of N-isopropyl-p-iodoamphetamine-iodine-123 (IMP). These patients were classified into three groups according to their clinical improvement three months later, and results of single photon emission computed tomography were compared with computed tomographic scan results and correlated to the clinical outcome. Regional brain hypoactivity of IMP differed in some cases between early and delayed IMP scans, showing in those cases a "redistribution" activity. The amplitude of this redistribution was significantly correlated with the clinical outcome of patients with stroke, whereas the value of hypoactivity on early IMP scan did not show such a correlation. The higher the redistribution amplitude was, the better was the clinical outcome. Comparative regional brain hypoactivity of IMP on early and delayed scans could represent a prognostic index of clinical recovery inasmuch as it gives information concerning viability of ischemic brain tissue.