[SPECT evaluation of effect of cerebral vasodilator by the subtraction method using Tc-99m HMPAO]

The effects of cerebral vasodilator are generally evaluated by observing whether the clinical improvement is applicable after the period of the drug administration. This report describes a novel approach to the evaluation for the effect of the drug using Tc-99m HMPAO. Consecutive brain Tc-99m HMPAO studies before and after a cerebral vasodilator, Ibudilast, administration were performed within 5 hours on 10 patients with cerebral infarction at chronic state. Five patients showed increased perfusion nearby the affected vascular territories after the po administration of Ibudilast. Significant changes in the brain perfusion pattern were determined using an image subtraction technique. This consecutive Tc-99m HMPAO subtraction SPECT technique seems to be useful for evaluating the therapeutic effect of cerebral vasodilator. This method can be performed within a short period of time, safely and sensibly.