Atrial volume reduction correlates with early improvement in hemorrhage-associated normal pressure hydrocephalus-a 3D computed tomography volumetric study.

Background: Hemorrhage-associated normal pressure hydrocephalus (HANPH) is a secondary hydrocephalus with limited research on ventricular volume changes and their correlation with clinical outcomes after ventriculoperitoneal shunting (VPS). Methods and materials: This retrospective pre-post within-subject study included 180 adult HANPH patients who underwent VPS. CT scans were obtained preoperatively and 2 weeks post-VPS. Lateral ventricular subregions (frontal horn, body, atrium, occipital horn, temporal horn) were segmented and measured using 3D Slicer. Gait ability, modified Rankin Scale (mRS), and Barthel Index (BI) were assessed. Early clinical improvement was defined as >25% gait improvement, >1-point mRS reduction, or >10-point BI increase. Results: Significant reductions in absolute volumes of lateral ventricular subregions were observed post-VPS. Postoperatively, the relative volume of the lateral body of the lateral ventricle increased, while that of other subregions decreased. Reductions in the absolute volumes of the frontal horn, temporal horn, and atrium negatively correlated with early clinical improvement. Logistic regression revealed that for every 5‰ reduction in volume of these subregions, the likelihood of clinical improvement significantly increased (180.3, 340.9, and 504.2%, respectively). Conclusion: The reduction in atrial volume of the lateral ventricle is crucial for early clinical improvement in HANPH post-VPS. Catheter placement in the occipital horn may optimize outcomes by effectively reducing atrial volume and minimizing risks. Prospective studies are warranted for validation.