Abstract T P18: Development of A SPECT-Based Objective Evaluating System for Therapeutic Effect of Acute Endovascular Therapy

Abstract

Background: and purpose Endovascular therapies (EVT) are increasingly preformed among patients with acute ischemic stroke in whom alteplase failed to recanalize or contraindicated. However, it is difficult to prove its efficacy by a randomized controlled study. Thus, we developed a SPECT-based objective evaluating system using a relative threshold value of cerebral blood flow (CBF) measured within the first 6 hours of onset. Methods: Between 2010 and 2012, 27 patients with supratentorial embolic stroke presented within 6 hours and contraindicated for intravenous rt-PA (16 men, 11 women, 74+/-12 years old, NIHSS median 19) were enrolled. After obtaining informed consent, all patients’ pre-treatment CBF was measured by 99mTc-HMPAO SPECT (tracer injection: median 361 min). All SPECT images were co-registered to individual FLAIR images and analyzed using the software developed for exclusive use (FusionViewer, Nihon Medi-Physics Co., Ltd, Japan). A predicted infarct size (x) was obtained 3-dimensionally as the sum of voxel sizes exhibiting <64% CBF of symmetrical voxel. Final infarct volume (y) was calculated on CT at 24 hours. A significant infarct size reduction was defined if final infarct volume was smaller than the lower 95% C.I. of the regression line [Y=0.8914X+3.742]. This study was approved by each IRB. Results: EVT was performed in 3 patients: 1 with localized intra-arterial thrombolysis (LIT), 1 with mechanical clot disruption (MCD) and 1 with LIT+MCD. A complete recanalization of M1/ M2 was obtained in 2 patients, while the other patient’s M1 recanalized partially. Median recanalization time was 5.1 (range 2.8~5.7) hours. All EVT patients had achieved significant infarct size reduction (predicted size: 121.9+/-47.1 cm3, final infarct size: 51.8+/-58.8 cm3). On the other hand, none of 24 patients without EVT showed significant infarct size reduction (predicted size: 97.2+/-74.6 cm3, final infarct size: 118.3+/-115.1 cm3). Conclusion: We confirmed the significant infarct size reduction obtained by EVT. This CBF based surrogate measure could be applied to the evaluation of various interventional therapies.