Predicting Aneurysm Occlusion After Pipeline Embolization: an Ensemble Model Using Angiographic Parametric Imaging.

BACKGROUND AND PURPOSE: The Pipeline Embolization Device (PED) revolutionized endovascular treatment of intracranial aneurysms (IAs), especially complex wide-neck lesions, but incomplete occlusion remains common. This study aimed to develop an ensemble model integrating clinical, morphological, and hemodynamic features for predicting post-PED occlusion outcomes.

MATERIALS AND

METHODS

This retrospective study included 306 patients with IAs treated with PED from January 2016 to June 2023. Clinical, morphological, and hemodynamic features were extracted from clinical records, three-dimensional rotational angiography, and digital subtraction angiography (DSA) to develop a weighted soft-voting ensemble model for predicting aneurysm occlusion at ≥6-month follow-up. The final prediction was generated by combining the weighted predicted probabilities from five individual algorithms rather than by a simple majority vote. Performance used area under the receiver operating characteristic curve (AUC) and confusion-matrix metrics; feature importance used SHapley Additive exPlanations (SHAP).

RESULTS

Among 306 patients (mean age 52.9±10.9 years; 192 women), pre- and post-PED hemodynamic features were extracted; 31 features (13 clinical/morphological, 18 post-PED hemodynamic-9 each from aneurysm and parent-artery regions of interest) were modeled. Complete occlusion was observed in 202/243 aneurysms (83.1%) in the internal dataset and 49/63 (77.8%) in the external test set. In the external test set, the ensemble achieved an AUC of 0.902 (95% CI, 0.82-0.98), an accuracy of 88.9% (95% CI, 78.5-95.2%), a sensitivity of 93.9% (95% CI, 82.8-98.7%), and a specificity of 71.4% (95% CI, 45.0-88.3%). Independent predictors of incomplete occlusion were branch involvement, daughter sacs, and older age. Post-PED changes (time-to-peak, mean-transit-time, cerebral-blood-volume) correlated with outcomes; complete occlusion associated with higher aneurysmal maximum intensity projection and parent-artery cerebral blood flow.

CONCLUSIONS

DSA-derived quantitative hemodynamic and morphological features are valuable biomarkers for PED efficacy. The ensemble showed robust performance (AUC 0.902; 95% CI 0.82-0.98) and may aid risk stratification and personalized IA treatment planning.