Abstract
Single photon emission computed tomography (SPECT) can provide information to help decide on the indication of surgical revascularization for hemodynamic cerebral ischemia. A recent Japanese EC-IC Bypass Trial (JET Study) showed that the EC-IC Bypass was beneficial for stroke prevention in patients with Stage II hemodynamic cerebral ischemia determined by quantified resting and acetazolamide-activated CBF-SPECT. Stage II hemodynamic cerebral ischemia may also be a surrogate marker of stroke recurrence. However, stratification of hemodynamic cerebral ischemia using quantified CBF-SPECT is not standardized enough at present. The dual table ARG (DTARG) method provided same-day quantification of both resting and acetazolamide-activated CBF using a split dose of ^<123>I-IMP and common arterial input function. In this method, both resting and acetazolamide-activated CBF-SPECT could be quantified pixel-by-pixel using the table look-up method with high measurement accuracy. On the other hand, segmental extraction estimation (SEE) analysis of CBF-SPECT displayed resting CBF, acetazolamide-activated CBF, cerebrovascular reserve [(acetazolamide-activated CBF-Resting CBF)/Resting CBF×100%] and severity of hemodynamic cerebral ischemia (Stage 0-II) pixel by pixel on the platform of 3-dimensional stereotactic surface projections (3D-SSP) of the standardized brain. In this analysis, severity of the hemodynamic cerebral ischemia could be estimated stereotactically based on identical vascular territories with high judgment accuracy. Stratification of hemodynamic cerebral ischemia using quantified CBF-SPECT should be standardized with high accuracy using the DTARG method and SEE analysis for universalizing the effectiveness of EC-IC Bypass surgery and organizing a future clinical trial.
