Comparative CT Ventricular Morphometrics in Hydrocephalus, Stroke, and Traumatic Brain Injury: A Distortion-Controlled Analysis.

Background/Objectives: Ventricular enlargement is a common finding on non-contrast computed tomography (CT) in acute neurological presentations, occurring in hydrocephalus, stroke, and traumatic brain injury. This study evaluated whether routinely available CT-based ventricular morphometric parameters can distinguish hydrocephalus from stroke and traumatic brain injury using initial imaging examinations. Methods: This retrospective observational study included 186 adults (68 with hydrocephalus, 64 with stroke, and 54 with TBI) who underwent index non-contrast cranial CT. Quantitative ventricular parameters included Evans index and third ventricle width, alongside temporal horn dilation and periventricular edema. Multivariable logistic regression models were developed to assess diagnostic performance. A primary morphometric model and a distortion-controlled model incorporating midline shift, mass lesions, and hemorrhage burden were analyzed. Discrimination was evaluated using receiver operating characteristic (ROC) curves. Results: Patients with hydrocephalus showed significantly greater ventricular enlargement, with higher Evans index and third ventricle width compared with stroke and traumatic brain injury groups. The primary model demonstrated moderate discrimination (AUC 0.71). After adjustment for intracranial distortion variables, model performance improved substantially (AUC 0.91), with balanced sensitivity and specificity at optimized thresholds. Evans index and third ventricle width were the strongest independent predictors. Conclusions: CT-derived ventricular morphometrics provide a practical and reproducible approach for differentiating hydrocephalus from stroke and traumatic brain injury on first-presentation CT, supporting objective interpretation in routine neuroimaging practice.