Role of Susceptibility Weighted Imaging (SWI) in Comparison to Magnetic Resonance Angiography in Assessment of the Intra-Arterial Thrombus in Patients with Acute Ischemic Stroke

Abstract Background Stroke occurs when the blood supply to the brain is cut off, usually due to a blood vessel burst or being blocked by a clot. This reduces the supply of oxygen and nutrients, causing brain tissue damage. The effects of a stroke depend on which part of the brain is injured. For this purpose, thrombus assessment in patients with acute stroke is of major clinical relevance since the location of the thrombus may determine the therapeutic decision. Aim of the Work Aim of study is to assess the role of susceptibility weighted imaging in assessment of intra-arterial thrombus in correlation with MRA and basic stroke protocol in patients with acute ischemic stroke. Patients and Methods This study is a cross-sectional study was conducted at Ain Shams University Hospitals at Radiology department. Our study included thirty patients with acute stroke symptoms in less than 24 hours of symptoms onset. The main source of data for this study was the prospectively conducted scans and clinical history of the patients referred to the MRI section of the department of Radiology, Ain Shams University Hospitals for doing MRI stroke protocol with addition of SWI sequence from November 2022 to June 2023. Results Thirty patients complaining of acute stroke symptoms in less than 24 hours of symptoms onset. Every single one of them went through MRI stroke protocol assessment and SWI sequence was added. So, SVS and TOF MRA were able to detect intra-arterial thrombus in acute stroke patients by 90 % and 95 %, respectively. There was no statistically significant difference in the rates of detection of intra-arterial thrombosis by SWI and MRA in patients with acute ischemic stroke (P = 0.57). The sensitivity of SWI for detection the intra-arterial thrombus in relation to MRA in MCA is 90%, in ACA and PCA is 100%, ICA is 66.7%. While specificity of SWI in relation to MRA in MCA is 80%, in PCA, ACA and ICA are 100%. The accuracy of SWI in assessment of intra-arterial thrombus in comparison to MRA in MCA is 94%, PCA 100%, ICA 95% and ACA 100%. The length of thrombus in SWI (lengthof SVS) could be measured ranging between 0.5-3.5 cm. Conclusion The SWI sequence needs to be incorporated into SWI stroke protocol for evaluating patients who have recently suffered an acute stroke as MRA and SWI techniques complement each other for visual detection of the occluded vessel. SWI has reasonable sensitivity, specificity and accuracy in the assessment of intra-arterial thrombosis in relation to MRA in patient of acute ischemic stroke. The „susceptibility sign' has a high sensitivity for diagnosing acute intracranial vascular blockage location and its extent in all major intracranial arteries. Also, it can be used in measuring the length of the intra-arterial thrombus over TOF MRA which cannot entirely demarcate thrombus length.