Baseline normalized wall index predicts delayed recanalization in internal carotid artery dissection with intramural hematoma: a high-resolution vessel wall imaging study.

OBJECTIVE

This study aims to investigate the evolution of intramural hematoma (IMH) in internal carotid artery dissection (ICAD) and identify predictors of favorable recanalization.

METHODS

This study cohort comprised 53 patients diagnosed with IMH due to ICAD on the basis of high-resolution magnetic resonance vessel wall imaging (HR-VWI) between June 2018 and June 2025. Thirty-eight medically managed patients underwent follow-up imaging. Neuroradiologists blinded to clinical data independently reviewed imaging. The primary outcome was favorable recanalization (<50% luminal stenosis) at follow-up, with the interval from symptom onset to the follow-up HR-VWI examination used as the time scale. Analyses included Cox regression, time-dependent ROC, landmark analysis, and bootstrap validation.

RESULTS

Among 38 patients with follow-up (median 138.0 days), IMH volume decreased to varying extents. Baseline normalized wall index (NWI) predicted favorable recanalization with an area under the curve (AUC) of 0.75 (95% CI, 0.58-0.87; P = 0.003). Time-dependent ROC analysis demonstrated improving predictive performance over time (AUCs: 0.57 at 90 days, 0.64 at 120 days, and 0.76 at 180 days). NWI cutoff values < 0.94 were associated with favorable recanalization. In multivariate Cox regression, NWI (adjusted hazard ratio, 0.13; 95% CI, 0.03-0.51; P = 0.003) was independently associated with the primary outcome. Landmark analysis at 90 days validated NWI's predictive value for delayed recanalization (AUC = 0.73). Bootstrap validation yielded an optimism-corrected AUC of 0.74 and C-index of 0.77.

CONCLUSION

Baseline NWI is an independent predictor of favorable recanalization in ICAD-IMH, with time-dependent efficacy. This underscores the potential value of HR-VWI in guiding therapeutic reassessment in patients with ICAD-IMH.