The Study Of Correlation Between Msct Perfusion Parameters And Clinical Condition In Acute Stroke And Clinical Outcome

Object This study attempts to evaluate varying degrees of cerebral perfusion status and collateral circulation perfusion situation in different periods of patients with ischemic stroke by using dynamic volume of the whole brain coverage4D CT angiography and CT perfusion (4D CTP-CTA) technology and magnetic resonance arterial spin labeling (Arterial Spin Labeling, ASL) technology. We also tried to predict clinical prognosis by using4D CTP-CTA and ASL when combining with follow-up imaging studies and clinical score. The correlation of these two methods was also analyzed.Methods63patients of clinical diagnosis of ischemic cerebrovascular disease in different stages of the onset (hyperacute to subacute) undertook CT scan and dynamic volumetric4D CTP-CTA. By using threshold of20%, the patients were divided into3groups according to the degree of rCBF, hyperperfusion (ipsilateral and contralateral the rCBF ratio>120%), and iso-perfusion (ipsilateral and contralateral rCBF ratio in the80%to120%) and lower perfusion group (ipsilateral and contralateral rCBF ratio <80%).45patients undertook magnetic resonance imaging (including conventional magnetic resonance imaging sequences, magnetic resonance diffusion weighted imaging and magnetic resonance angiography) before and after the0.5hours to3days of4D CTP-CTA.15of them undertook ASL perfusion imaging as well. CT or MRI imaging followed up40patients14to30days after the initial examination.28of them had routine head CT scan, and12of them had cranial MRI scan.41patients had initial NIHSS score by an experienced neurologist. Analysis of the results of different degree of perfusion, and clinical situation were analyzed.Results (1) Sensitivity of4D CTP-CTA was93.44%, with specificity of100%;(2)4D CTP-CTA can effectively show the whole brain lesions, including the infratentorial lesion and the lesions above the ventricle, even for lacunar ischemic lesions;(3) Brain tissue is likely to infarct when rCBF<56%; and it is likely to survive when rCBV>80%, and with small infarct and good prognosis. When large area of ischemia involved unilateral hemisphere, patients with high NIHSS and bad prognosis (P<0.01);(4) When large area of ischemia involved multiple level of unilateral hemisphere, the corresponding arteries were usually stenosis or occlusion, 96.4%(27/28) in our study;(5) Patients with good collateral circulation infarct size and better clinical outcomes;(6) In this study,15patients undertook ASL imaging. One of them showed vascular dysplasia on4D CTA with prolonged TTP on CTP but normal on ASL. Two cases of TIA showed normal on both4D CTP-CTA and ASL. The remaining12cases were ischemic stroke patients. For three delay time points,1500ms was the best for images acquisition and showed better CBF image quality in13/15patients (86.67%).2000ms was the best for2/15patients (13.33%). ASL was negative in8patients with1of pontine infarct,7of lacunar infarct. Four cases were positive finding with3showed reduction of CBF1showed increased CBF. The sensitivity was33.33%and specificity was100%. The CTP-CBF value was no significant different with that of ASL.Conclusion (1)4D CTP-CTA of ischemic cerebrovascular disease diagnostic is sensitive and specific, which can be used as emergency routine examination.(2) a one-stop whole cerebral dynamic volume CT dynamic imaging accurately determine the ischemic brain tissue of hemodynamic changes, combined with the dynamic the CTA, displays cerebral hemodynamic changes. It is a reliable and helpful imaging examination method in clinical individual treatment program, providing more accurate and comprehensive imaging evidence. The advantage of4D CTP-CTA were:(a) the coverage was enlarged when compared with other previous CT perfusion increases, reaches the whole brain coverage;(b) the CTP scanned while shortening the scanning time, and without additional injection of contrast agent;(c)4D CTP-CTA technology, with great time resolution, can display blood flow from pure arterial phase to the pure venous phase and any phase between them;(d) a one-stop scanning greatly reduce patient radiation dose.(3)4D CTA can be used to display collateral vessels, which is expected to be a new image means to replace DSA to evaluate collateral circulation, and to improve people’s understanding of the pathophysiological characteristics of the collateral circulation.(4) As for CTP manifestations of venous sinus thrombosis or vascular malformations, pending further study of larger sample is needed.(5) In this study,1.5T MR scanners was used to acquire ASL image, results in low resolution compared with CTP. But for the patients with larger lesions and patients with iodine allergy the contraindication and renal dysfunction, ASL still is a good choice.