الفهرس 
ANATOMYOnly 14 pages are availabe for public view
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Abstract
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 decisions.
TOF MRA is a frequently used imaging modality in the evaluation of acute stroke patients and can demonstrate stenosis or occlusion in the major intracranial arteries.
Susceptibility weighted imaging (SWI) is a newly developed magnetic resonance (MR) protocol. Recent studies have found that SWI may be useful in the field of cerebrovascular diseases, especially for detecting the presence of the susceptibility vessel sign (SVS). It has been found useful in the assessment and follows up of acute stroke patients. This imaging tool can give critical information regarding the presence of hemorrhage and intra-arterial thrombotic occlusions that could both have significance in the assessment of acute stroke patients.
Our study is a cross-sectional study was conducted at Ain Shams University Hospitals at Radiology department. It included forty patients complaining of acute stroke symptoms in 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, at Ain Shams University Hospitals for doing MRI stroke protocol with addition of SWI sequence over a course of 9 months.
SVS and TOF MRA were able to detect intra-arterial thrombus in acute stroke patients by 95 % and 97.5 % 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=0.556).
The sensitivity of SWI for detection the intra-arterial thrombus in relation to MRA in MCA is 94.3%, 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 92.5%, PCA 100%, ICA 97.5 and ACA 100%. The length of thrombus in SWI (length of SVS) could be measured ranging between 0.4-3 cm.
In our study, the sensitivity of SWI for detection the intra-arterial thrombus in relation to MRA in MCA is 94.3% while the specificity is 80%., The Sensitivity of SWI in ACA and PCA is 100% while the specificity of SWI is 100%. The sensitivity of SWI in ICA is 66.7% while specificity is 100%.
The agreement between SWI and MRA in the assessment the site of intra-arterial thrombus in MCA is 100%. It is highly significant relation between MRA and SWI to assess the site of intra-arterial thrombus in MCA (P-value=0.00).
So, the susceptibility indication is a very helpful indicator in localizing the thrombus that is found inside the vessel. The susceptibility sign has a high sensitivity for diagnosing acute intracranial vascular blockage and its extent in all major intracranial arteries, including the anterior cerebral, middle cerebral, and posterior cerebral arteries, as well as the basilar and vertebral arteries.
So SWI and TOF MRA should be used as complementary imaging modalities to each other in the assessment of acute thrombotic occlusion in stroke patients. 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, including the anterior cerebral, middle cerebral, and posterior cerebral arteries, as well as internal carotid arteries.
Also, SWI can be used in measuring the length of the intra-arterial thrombus over TOF MRA which cannot entirely demarcate thrombus length.