Noninvasive Quantitative Assessment of Cerebral Blood Flow(CBF) using 99mTc-ECD SPECT with adjunctive Radionuclide Angiography in Ischemic Stroke

Abstract

Background and objectives : Quantitative CBF measurements are essential for diagnosing ischemic lesion and evaluating the therapeutical effects and predicting the prognosis of cerebral ischemia. Even though several methods have been introduced, these techniques are too cumbersome and invasive to be applied to routine studies. In this study, a non-invasive simple method for the quantitative evaluation of CBF is presented using 99mTc-ECD SPECT with adjunctive radionuclide angiography. Methods : Twenty normal controls and 27 patients with unilateral carotid ischemic stroke were selected. Brain perfusion index(BPI) of each hemisphere was measured in each subject by acquisition of serial radionuclide angiography after injection of 20ml of 99mTc-ECD. With Lassen`s correction algorithm of curve-linear relationship between the brain activity and blood flow, rCBF on transaxial SPECT slice corresponding with MRI lesion sites (ischemic core, border zone and contralateral mirror locus) were calculated. Results : BPI values for normal controls showed a significant negative correlation with advancing age(r=-0.64 p=0.021) and hemispheric BPI were 11.02+/-1.6 and 7.8+/-1.4 for normal controls and patients, respectively. Significant differences were observed between two groups (p=0.0012). rCBF obtained from core zone (12+/-2.5 ml/100g/min), border zone (29.9+/-8.1) and contralateral mirror locus (52.1+/-15.1) were clearly defined in each subject of patients group. The cerebral reserve capacity after diamox injection were also easily quantified in patient group and these results are well correlated with conventional angiographic findings. Conclusion : Measurements of BPI and rCBF using 99mTc-ECD SPECT with adjunctive radionuclide angiography could be an useful, simple and non-invasive quantitative method in evaluation of the cerebral blood flow in the ischemic stroke.