Noninvasive assessment of quantitative regional cerebral blood flow and tissue viability in ischemic cerebrovascular disorders using N-isopropyl-p-(I-123) iodoamphetamine

Single photon emission computerized tomography (SPECT) with N-isopropyl-p-(I-123) iodoamphetamine (IMP) were performed in 25 patients with ischemic cerebrovascular disorders. IMP distribution patterns were simulated as follows: (1) redistribution representing a hypoperfusion area without tissue impairment; (2) persistent hypoactivity representing a hypoperfusion area with tissue impairment; and (3) reverse redistribution representing impaired tissue with over-perfusion in comparison with its demand. These patterns were confirmed in the patients. Redistribution was observed in 21 regions of interest (ROI) in 11 patients; persistent hypoactivity was observed in 17 ROIs in 17 patients; reserve redistribution was observed in one patient with hemorrhagic infarction with the recanalization of the middle cerebral artery occlusion. The rCBF values of the unaffected side, the redistribution area, and the persistent hypoactivity area were 58.7 +- 3.2, 36.9 +- 2.1, and 25.5 +- 2.7 ml/100 g/min, respectively. Significant differences were observed between the unaffected side and the redistribution area and between the redistribution area and the persistent hypoactivity area. In conclusion, IMP SPECT and rCBF measurements proved to be useful in assessing ischemia, especially reversible ischemia and luxury perfusion. (Namekawa, K.)