Collaborative use of susceptibility weighted Imaging with diffusion weighted imaging and Magnetic resonance angiography in the Assessment of acute arterial stroke using 3t Mri– a one year hospital based cross -sectional Study

Abstract

INTRODUCTION Acute stroke is characterized by sudden onset of localized neurologic impairment, often with progressive worsening of symptoms. Instead of relying on stroke duration, imaging modalities like MRI can be used to measure tissue viability and estimate the time of stroke onset, known as the "tissue clock." This approach helps determine intervention timeframes. Thrombolytic treatment must be delivered within six hours of the onset of stroke to dissolve clots and restore blood circulation. Hence, for patients with an unknown stroke onset time, the most effective way to estimate it is using Diffusion weighted imaging (DWI) - Fluid attenuated inversion recovery (FLAIR) mismatch. The SWI-DWI mismatch is a significant indicator in acute ischemic stroke, indicating the presence of an ischemic penumbra. Patients with this mismatch have a higher rate of favourable outcomes after thrombolytic therapy compared to those without the mismatch, suggesting it can be used as an alternative method to select appropriate candidates for thrombolysis. SWI can detect cerebral microbleeds, which may increase the risk of bleeding with thrombolytic or antithrombotic therapy. Patients with a small number of microbleeds can be safely treated, while multiple microbleeds may indicate a higher risk. SWI can also identify the susceptibility vessel sign, which helps locate the precise position of the intraarterial thrombus, complementing the information provided by time-of-flight MRA on arterial occlusion. OBJECTIVES · To study the synergistic effect of SWI with DWI and MRA in the assessment of Acute Ischemic Stroke · To evaluate if SWI and DWI are more efficient than conventional MRI sequences for evaluating stroke and selecting patients for thrombolytic treatment.