Lightweight Classifier for Detecting Intracranial Hemorrhage in Ultrasound Data

Intracranial hemorrhage (ICH) secondary to Traumatic Brain Injury (TBI) represents a critical diagnostic challenge, with approximately 64,000 TBI-related deaths annually in the United States. Current diagnostic modalities including Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have significant limitations: high cost, limited availability, and infrastructure dependence, particularly in resource-constrained environments. This study investigates machine learning approaches for automated ICH detection using Ultrasound Tissue Pulsatility Imaging (TPI), a portable technique measuring tissue displacement from hemodynamic forces during cardiac cycles. We analyze ultrasound TPI signals comprising 30 temporal frames per cardiac cycle with recording angle information, collected from TBI patients with CT-confirmed ground truth labels. Our preprocessing pipeline employs z-score normalization and Principal Component Analysis (PCA) for dimensionality reduction, retaining components explaining 95% of cumulative variance. We systematically evaluate multiple classification algorithms spanning probabilistic, kernel-based, neural network, and ensemble learning approaches across three feature representations: original 31-dimensional space, reduced subset, and PCA-transformed space. Results demonstrate that PCA transformation substantially improves classifier performance, with ensemble methods achieving 98.0% accuracy and F1-score of 0.890, effectively balancing precision and recall despite class imbalance. These findings establish the feasibility of machine learning-based ICH detection in TBI patients using portable ultrasound devices, with applications in emergency medicine, rural healthcare, and military settings where traditional imaging is unavailable.