Acute brain infarct is a medical emergency potentially reversible if treated with thrombolysis, an approved therapy, if performed in the first 3 to 6 hours of evolution. Thrombolysis has many benefits, but it also has associated risks, mainly development of intracranial hemorrhage. The selection of which patient should receive this type of treatment had been an important research topic over the last decade. As a consequence neuroimaging of brain infarct has significantly improved during the last few years. A variety of diagnostic studies are now available in the evaluation of brain infarct and in particular of potentially reversible brain ischemia, including magnetic resonance imaging (MRI) diffusion-perfusion, perfusion computed tomography (CT) and functional neuroimaging techniques includes positron emission tomography (PET) and single-photon emission tomography (SPECT). The aim of this study is to present our experience with a group of patients that presented with acute brain ischemia and had a NeuroSPECT evaluation before and after intra-arterial thrombolysis and/or possible stent placement, in the treatment of acute brain infarct.
METHODS: 16 patients were treated acutely for a significant ischemic stroke with the following protocol. 1) Admission, and complete neurological evaluation. 2) Brain CT scan performed to rule out hemorrhage or established infarct. 3) IV injection of 1100MBq Tc99m HMPAO (Ceretectm) 4) Conventional cerebral angiography and intra-arterial thrombolysis with tPA and /or angioplasty/stent if necessary. 5) NeuroSPECT assessment of ischemic penumbra (Pre-therapy results). 6) 14 of 16 patients received a NeuroSPECT (Post-therapy results) control at 24 hours.
NeuroSPECT image acquisition was performed immediately following arterial thrombolysis with a dual Head Camera, Siemens ECAM, SHR collimators and conventional protocol. Image processing was performed using the Neurogam, Segami Corp. Software as previously reported in Alasbimn Journal 2(7): April 2000. http://www.alasbimnjournal.cl. The analysis consists of 1) Talairach brain volume normalization. 2) Voxel by voxel comparison of the individual brain cortex uptake normalized to the maximum in the cortex with a normal database of 24 age-matched controls.
RESULTS: The results were expressed in standard deviations (SD) below the normal mean. Normal mean is 72 ± 5 % of maximum in the brain cortex. Thrombolysis significantly reduced the brain hypoperfusion of the studied patients. Overall, 7 of 16 patients made good clinical recovery (mR 0-1) after the thrombolysis treatment. 7 of 16 patients made a moderate to poor clinical recovery (mR 2-4) and 2 of 16 patients died. The best clinical outcomes were found when successful recanalization of the occluded vessel was achieved in the presence of only moderate or superficial cerebral hypoperfusion. Patients that presented with large areas of severe brain hypoperfusion tended to have a worse outcome.
CONCLUSIONS: NeuroSPECT examination 1) Provides useful information of infarct/penumbra during the first hours of evolution. 2) Evaluates the efficacy of thrombolysis and also angioplasty and stenting therapy. 3) Helps anticipate post therapy evolution.
Key Words: Brain infarct; Thrombolysis; HMPAO; SPECT
