A feasibility study: Freehand 3D volumetric reconstruction ultrasound scanning for midline measurement in adults

Midline shift (MLS) is a diagnostic marker for brain pathologies such as intracranial hemorrhage and traumatic brain injury, requiring emergent treatment. CT and MRI are the gold standards for MLS measurement but prevent repeated, short-interval monitoring and are associated with significant risks when transporting critically ill patients. This feasibility study investigates a freehand 3D ultrasound (US) system for bedside MLS measurement. Using electromagnetic position trackers on both the US transducer and the subject, we reconstructed 2D B-mode ultrasound images into a 3D volume. We scanned a healthy subject through bilateral transtemporal windows and measured MLS on the reconstructed volume. Our system achieved a measurement error comparable to existing sonography-based methods, fitting clinical requirements, and proving its feasibility for clinical use. Our approach reduces operator-skill dependency and provides a rapid, non-ionizing solution for continuous, short-interval monitoring of MLS, potentially enhancing clinical decision-making in critical care and emergency field diagnosis.