Pre-treatment prolonged venous transit independently predicts the post-treatment Brush Sign in AIS-LVO patients despite successful macrovascular reperfusion, linking macroscopic venous congestion to downstream microvascular failure.
Pre-treatment prolonged venous transit (PVT) positivity was significantly more prevalent in patients who developed the post-treatment Brush Sign compared to those who did not.
Pre-treatment PVT was an independent predictor of the post-treatment Brush Sign after adjustment for multiple covariates in multivariable logistic regression.
The association between PVT and the Brush Sign was robust across multiple sensitivity analyses.
The Brush Sign on susceptibility-weighted imaging reflects microvascular venous congestion and the no-reflow phenomenon occurring despite successful macrovascular reperfusion.
PVT on CTP is identified as an easily accessible imaging biomarker for anticipating the no-reflow phenotype in AIS-LVO patients.
This research suggests that a specific finding visible on standard pre-treatment brain imaging — called prolonged venous transit (PVT), which reflects sluggish blood drainage through large veins — can predict whether a stroke patient will later show signs of microscopic blood vessel failure, even after successful removal of the blood clot. The microscopic failure is detected on follow-up MRI as the 'Brush Sign,' which indicates that tiny blood vessels in the brain remain congested despite the main blockage being cleared. In a study of 187 stroke patients who all had their major artery successfully reopened, those with pre-treatment PVT were nearly four times more likely to develop the Brush Sign afterward. This matters because successful mechanical thrombectomy — the procedure used to physically remove stroke-causing blood clots — does not always translate into full recovery of blood flow at the microscopic level, a problem known as the 'no-reflow' phenomenon. This study suggests that doctors may be able to identify which patients are at risk for this microscopic failure before treatment even begins, simply by examining the venous drainage patterns on CT perfusion scans that are already routinely performed during stroke workup. This research suggests that monitoring venous outflow, not just arterial blockage, could be an important part of stroke imaging assessment. Identifying patients likely to experience the no-reflow phenomenon early could potentially open the door to targeted treatments aimed at protecting small blood vessels, though further research would be needed to determine whether such interventions improve patient outcomes.
Tsang D, Gad M, Cho A, Lalwani K, Salim H, Lakhani D, et al.. (2026). Baseline prolonged venous transit on CT perfusion predicts the post-treatment Brush Sign after successful reperfusion in acute ischemic stroke patients.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1819534