Evaluation of cerebral blood flow reserve in patients with cerebrovascular disease by SPECT using technetium-99m-L, L-ethyl cysteinate dimer

A technique for measuring the resting and acetazolamide (Acz)-activated cerebral blood flow without blood sampling by consecutive single-photon emission computed tomography (SPECT) using technetium-99m-L, L-ethyl cysteinate dimer (99mTc-ECD), called the 99mTc-ECD-RVR method, was recently developed by Matsuda et al . and Takeuchi et al . We evaluated the cerebral blood flow reserve in 77 patients with cerebrovascular diseases and 24 controls using this method. Baseline mean CBF (mCBF)was calculated from the application of Patlak plot graphical analysis with radionuclide angiography, and quantitative regional CBF (rCBF) images were obtained from qualitative axial SPECT images by the mCBF and Lassen’s linearization correction. The activated SPECT images were obtained by subtraction of the first image from the second image. The mean increment ratio (IR) by calculating the mean CBF for the pre- and post-Acz in the controls was 1.26±0.12 (mean±SD). In patients with cerebrovascular disease, the reduction of the mean IR and regional IR was parallel with the degree of stenosis. This noninvasive method was also considered to be useful in evaluating the change in the hemodynamic reserve in cerebrovascular disease.