Changes in translesional pressure ratio were more closely associated with post-stenting improvement in perfusion-delay metrics than geometric stenosis measures alone, suggesting that pressure ratio may serve as an intermediate hemodynamic marker linking anatomical remodeling with downstream perfusion imaging changes.
Key Findings
Results
Intracranial stenting significantly improved luminal morphology, hemodynamic parameters, and CT perfusion metrics in patients with severe ICAS.
131 patients with severe ICAS (70-99% stenosis) were analyzed retrospectively at a single center.
108 patients had anterior circulation lesions; 77 were male (71.3%); median age was 65.50 years (IQR 57.00-69.00).
All improvements in morphological, hemodynamic, and CT perfusion metrics were statistically significant (all p < 0.05).
Vascular morphology was assessed by digital subtraction angiography, hemodynamics by computational fluid dynamics, and perfusion by CT perfusion imaging.
Results
After adjustment for hemodynamic changes, morphological changes were no longer independently associated with perfusion imaging changes.
Multivariable analysis was used to assess independent associations among morphological, hemodynamic, and perfusion changes.
This finding suggests that the relationship between anatomical remodeling and perfusion improvement is mediated through hemodynamic changes rather than being direct.
Correlation, multivariable, and mediation analyses were all employed to examine these relationships.
Results
Changes in pressure ratio (ΔPR) showed the strongest associations with reductions in Tmax-based perfusion-delay volume among all hemodynamic parameters examined.
ΔPR demonstrated nonlinear threshold effects in its association with perfusion-delay volume reduction.
ΔPR had a significant mediating effect on the association between morphological remodeling and improvement in perfusion-delay metrics.
Tmax (time-to-maximum of the residue function) was used as the primary perfusion-delay metric in CT perfusion analysis.
Pressure ratio was computed using computational fluid dynamics modeling.
Results
The associations between pressure ratio changes and perfusion improvement were more evident in the anterior circulation than in the posterior circulation.
108 of 131 patients (82.4%) had anterior circulation lesions, providing a larger subsample for anterior circulation analysis.
Subgroup analyses by circulation territory (anterior vs. posterior) were conducted.
The finding suggests that hemodynamic-perfusion relationships may differ by vascular territory.
Discussion
Pressure ratio may serve as an intermediate hemodynamic marker linking anatomical remodeling with downstream perfusion imaging changes after intracranial stenting.
Mediation analysis demonstrated a significant mediating role of ΔPR between morphological remodeling and perfusion-delay metric improvement.
Geometric stenosis measures alone were less closely associated with post-stenting perfusion improvement compared to pressure ratio changes.
The authors suggest pressure ratio could be a clinically useful hemodynamic marker beyond simple anatomical stenosis grading.
These findings were derived from a retrospective single-center study design, which may limit generalizability.
What This Means
This research suggests that when doctors place stents inside narrowed brain arteries to treat intracranial atherosclerotic stenosis (hardening and narrowing of arteries inside the skull), the physical opening of the artery alone does not directly explain improvements in blood flow to brain tissue. Instead, this study of 131 patients found that improvements in a pressure-based measurement — the ratio of blood pressure across the narrowed segment — appears to be the critical link between how much the artery physically widens and how much blood flow to the brain actually improves, as measured by CT perfusion imaging.
The key finding is that a measure called the 'pressure ratio' (which captures how much blood pressure drops across the narrowed artery segment) mediated the relationship between anatomical improvement and downstream perfusion improvement. When researchers statistically accounted for pressure ratio changes, the direct relationship between physical artery widening and brain perfusion improvement disappeared, suggesting pressure ratio is an important 'middleman' in this chain. This association was particularly strong when looking at arteries in the front part of the brain (anterior circulation) and showed a nonlinear, threshold-like pattern.
This research suggests that simply measuring how much a stent physically widens an artery (using imaging like angiography) may not be the best way to predict whether a patient's brain blood flow will actually improve. Measuring the pressure ratio across the stented segment — which requires computational modeling in this study — may provide more meaningful information about treatment success. If confirmed in future prospective studies, these findings could potentially inform how clinicians assess and optimize intracranial stenting procedures for patients with severe brain artery disease.
Yin X, Li Z, Huang F, Chen Y, Hong T, You Y, et al.. (2026). Exploratory analysis of morphology-hemodynamics-perfusion relationships after intracranial stenting in severe intracranial atherosclerotic stenosis.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1900989