Association between the Perfusion/Diffusion and Diffusion/FLAIR Mismatch: Data from the AXIS2 Trial

Abstract

The perfusion-/diffusion-weighted imaging (PWI/DWI) mismatch and the diffusion/fluid attenuated inversion recovery (DWI/FLAIR) mismatch are magnetic resonance imaging (MRI) markers of evolving brain ischemia. We examined whether the DWI/FLAIR mismatch was independently associated with the PWI/DWI mismatch. Furthermore, we determined whether the presence of the DWI/FLAIR mismatch in patients with the PWI/DWI mismatch would provide additional information regarding last seen normal time (LTM). We used data from the 'AX200 for ischemic stroke' trial (AXIS 2 study NCT00927836). We studied the association between the presence of the DWI/FLAIR and PWI/DWI mismatch, baseline National Institute of Health Stroke Scale (NIHSS), age, ischemic-core volume, gender, intravenous (IV) tissue plasminogen activator (tPA), and perfusion-mismatch volume in univariate analysis. Significant variables (P<0.05) were added into the final multivariate model. We analyzed 197 patients. Seventy-two (37%) had both the PWI/DWI and the DWI/FLAIR mismatch. Patients with the double mismatch pattern had a shorter LTM than patients with the PWI/DWI mismatch alone (Median difference 90 minutes, P<0.01). Multivariate analysis confirmed the independent association between the two mismatch patterns (odds ratio (OR) 2.6, 95% confidence interval (CI) 1.2 to 5.4). Our study implies that the DWI/FLAIR mismatch and PWI/DWI mismatch are strongly associated, independent from LTM. Furthermore, in the presence of the PWI/DWI mismatch, the DWI/FLAIR pattern indicates a shorter LTM. This could have implications in selecting patients for reperfusion therapy.

Unknown‐onset strokes with anterior circulation occlusion treated by thrombectomy after DWI‐FLAIR mismatch selection

“…Indeed, it has been proved that the infarct core volume does not strictly depend on time but more on the competence of the collateral arteries in patients presenting with proximal anterior circulation occlusion . By selecting patients on DWI‐FLAIR mismatch, which is strongly associated with perfusion‐weighted imaging/DWI mismatch , a physiopathological concern in selection may have been introduced which possibly led to selecting ‘slow progressors’ with a competent collateral circulation, and therefore less affected by longer time intervals . Still, it remains unclear whether patients presenting with significant DWI‐FLAIR mismatch are slow progressors with competent collaterals or just UOS identified in the earlier hours of stroke, with potentially fast infarct core growth.…”

Diffusion-Weighted Imaging-Fluid-Attenuated Inversion Recovery Mismatch Is Associated with 90-Day Functional Outcomes in Patients Undergoing Mechanical Thrombectomy

“…On the other hand, DWI-perfusion weighted imaging mismatch has been recognized as a marker of the ischemic penumbra, despite the need for contrast media [5]. Because DWI-FLAIR mismatch is strongly associated with DWI-perfusion weighted imaging mismatch [22], future research is needed to elucidate the relation between ischemic penumbra and DWI-FLAIR mismatch.…”

Evaluation of Enhanced Learning Techniques for Segmenting Ischaemic Stroke Lesions in Brain Magnetic Resonance Perfusion Images using a Convolutional Neural Network Scheme

“…Together with the perfusion/diffusion mismatch it is recognised as an MRI marker of evolving brain ischemia. A clinical trial that examined whether the DWI/FLAIR mismatch was independently associated with the diffusion/perfusion mismatch or not, concluded that in the presence of the latter, the DWI/FLAIR pattern could indicate a shorter time between the scan and the last time the tissue seen was normal (Wouters et al, 2015). The CNN scheme evaluated does not take into account the time from the stroke onset - information not provided.…”