A Multiparametric MRI Framework for Ultra-sensitive Diagnosis of Acute Ischemic Stroke in Ultra-early Stage

Early diagnosis of acute ischemic stroke (AIS) is critical for effective treatment, yet the current gold standard, diffusion-weighted imaging (DWI), may fail to detect injuries in the ultra-early stage when cytotoxic edema is still minimal. To address this limitation, herein, a novel multiparametric magnetic resonance imaging (MRI) strategy was developed, focusing on sensitive vascular changes that precede irreversible tissue damage. This approach utilizes a NaGdF4 nanoparticle-based contrast agent to simultaneously enhance susceptibility-weighted imaging (SWI) and dynamic contrast-enhanced (DCE) MR angiography. The combined application enables high-resolution visualization of the earliest microvascular alterations following arterial occlusion. Specifically, collateral vessels with diameters below 105 μm, formed via rapid vascular dilation and anastomosis, were clearly delineated by SWI, outlining the ischemic territory. Concurrently, DCE MR angiography precisely identified the site of arterial occlusion and assessed cerebral perfusion deficits. This NaGdF4-enhanced multiparametric MRI method demonstrates potential as a more sensitive diagnostic tool than DWI for ultra-early AIS. By directly imaging the formation of collateral circulation and vascular occlusion, it allows for the detection of ischemia before it becomes apparent on DWI. This strategy provides a valuable alternative to DWI, promising to improve diagnostic accuracy and enable timely intervention in the critical early phase of stroke.