Association of intravascular enhancement sign on 3D-T1W TSE with collateral status in middle cerebral artery occlusion stroke.

Objective: The significance of the intravascular enhancement sign (IVES) on high-resolution magnetic resonance vascular wall imaging (HR-VWI) remains unclear. This study aimed to investigate the correlation between the IVES and collateral assessment derived from digital subtraction angiography (DSA).

Method: A total of 75 patients with occlusion of the first segment of the middle cerebral artery (MCA) who underwent HR-VWI and DSA examinations at our research institution between November 2016 and February 2023 were included. The number of vessels with IVES, IVES-Alberta Stroke Program Early Computed Tomography Score (ASPECTS), American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral grade, and DSA collateral blood flow grade were retrospectively evaluated. Correlations between these indicators were assessed using Spearman's correlation.

Results: Interrater agreement was good for the assessment of HR-VWI and DSA indicators. After adjustments for age, degree of wall enhancement, and hypertension, a multivariable ordinal logistic regression model identified both the number of IVES vessels (OR = 1.37; 95%CI [1.06-1.78]; P = 0.017) and IVES-ASPECTS (OR = 2.00; 95%CI [1.03-3.87]; P = 0.041) as independent predictors of ischemic stroke. In the patient group with acute ischemic stroke, we found weak correlations between the number of IVES vessels and the ASITN/SIR collateral grade (rho = -0.35; P = 0.002) and between the IVES-ASPECTS and ASITN/SIR collateral grade (rho = -0.27; P = 0.02). Moreover, there were strong correlations between the number of IVES vessels and the DSA collateral blood flow grade (rho = -0.74; P < 0.001) and between the IVES-ASPECTS and the DSA collateral blood flow grade (rho = -0.65; P < 0.001). The number of IVES vessels correlated strongly with the IVES-ASPECTS (rho = 0.92, P < 0.001).

Conclusion: We find that the IVES is closely associated with sluggish collateral blood flow, which further confirms the hemodynamic mechanism underlying the IVES in MCA occlusion.