Value of single-photon emission-computed tomography in acute stroke therapeutic trials.

Abstract

Background and Purpose: New therapeutic interventions for acute ischemic stroke are aimed at improving cerebral blood flow in the first 3 to 6 hours after symptom onset. Single-photon emissioncomputed tomography (SPECT) performed in the setting of clinical therapeutic trials may give us a better understanding of the physiological response to new forms of treatment and could impact acute management decisions.Methods: We prospectively studied 15 patients with hemispheric ischemic stroke with SPECT within 6 hours of symptom onset and again at 24 hours. The ischemic defect was assessed in a semiquantitative manner that used computer-generated regions of interest (SPECT graded scale). This measure was correlated with clinical presentation (National Institutes of Health [NIH] Stroke Scale), initial clinical course (change in NIH Stroke Scale), long-term outcome (Barthel Index at 3 months), and complications of cerebral hemorrhage and edema.Results: The severity of the SPECT graded scale on the admission scan correlated with the severity of neurological deficit (admission NIH Stroke Scale) (P<.05) and was positively associated with poor long-term outcome as measured with the Barthel Index (P<.001) and the complications of cerebral hemorrhage and massive cerebral edema (P<.005). In fact, there was a threshold value for the SPECT graded scale above which all patients suffered poor long-term outcome and the complications of cerebral hemorrhage and edema.Conclusions: The measurement of an ischemic defect using SPECT is a valid assessment of hemispheric stroke severity in the hyperacute setting and may be useful for selecting or stratifying patients in clinical therapeutic trials. (Stroke. 1993;24:1322-1329

99m Technetium-Ethyl-Cysteinate-Dimer Single-Photon Emission CT Can Predict Fatal Ischemic Brain Edema

“…The SPECT graded scale in our semiquantitative SPECT analysis is a combination of the size and extent of ischemia and had a high sensitivity and specificity to predict malignant MCA infarction/death. This confirms the results of Hanson et al, 29 who also found a strong association between the severity of ischemia (SPECT graded scale) on the initial SPECT scan and poor long-term outcome (Barthel Index), albeit among just 15 patients examined within 6 hours.…”

“…A few SPECT studies performed within 6 hours of stroke onset relied on small patient numbers and did not address the prediction of death after stroke. 29,[33][34][35][36] These studies exclusively used the tracer 99m Tc-HMPAO, which assesses cerebral blood flow. By contrast, the tracer 99m Tc-ethyl-cysteinatedimer (ECD) reflects not only perfusion but also the metabolic status of the brain tissue and may be more specific for revealing the degree of irreversible brain lesions.…”

“…42 Count densities of ROIs of the symptomatic hemisphere were related to those of the corresponding contralateral regions and classified as abnormal if a deficit was Ͼ10% (ratio Յ0.90), in agreement with widely accepted standards. 29,43 In accordance with Hanson et al, 29 we also used the SPECT graded scale, a measure of the intensity and spatial extent of activity deficits. Each ROI was given a score of 0 to 9, whereby 0 indicated a ratio Ն0.91, 1 indicated a ratio of 0.81 to 0.90 (corresponding to 81% to 90% activity compared with the contralateral side), 2 indicated a ratio of 0.71 to 0.80, etc.…”

Nimodipine and Perfusion Changes After Stroke

“…It additionally emphasizes the importance of outcome SPECT studies in retrospectively distinguishing the nutritional and nonnutritional components of early reperfusion. Previously published studies by our group 18,19 and others 32,33 have shown that acute reperfusion after therapeutic intervention does not necessarily correlate with clinical gains. By supplementing early studies with studies in the chronic phase, we have shown that the enhanced early reperfusion after nimodipine did not correlate with clinical improvement because it was transient and occurred in nonviable tissue.…”

Severe ischemic stroke due to progression of cervical carotid artery dissection

“…The mechanism(s) underlying cerebral ischemic symptoms is thought to be hemodynamic at first as a result of significant stenosis or occlusion of the carotid artery involved by dissection extending to the A1 segment. 6,22 . In our case, immediate STA-MCA anastomosis was completed within the therapeutic time window [23][24][25] and narrowly escaped fatal deficits developed. There has not been established authentic strategies for the spontaneous dissection of the CS ICA to prevent complete stroke yet.…”