Experimental study of high-resolution ultrasound imaging of hemorrhage, bone fragments, and foreign bodies in head trauma.

The accuracy of high-resolution ultrasound scans in detecting foreign bodies and hemorrhage within the brain was evaluated by comparison with computerized tomography (CT) scans and gross pathology. The test lesions were blood and foreign bodies consisting of bone, wood, and metal placed in the brain of an experimental animal. High-resolution ultrasound scans (10 MHz) performed in coronal and sagittal planes accurately delineated the position and spatial orientation of these foreign bodies and hemorrhage. Both hemorrhage and foreign bodies were echogenic compared to normal, hypoechoic brain parenchyma. Metal fragments had a highly characteristic echo pattern caused by sound reverberation within the object. Acute intracerebral hemorrhage produced an ultrasound image consisting of sharply circumscribed homogeneous echoes. The sonographic shape of intracerebral hemorrhage correlated closely with the area of increased density seen on the CT scan. High-resolution ultrasonography accurately delineated experimentally produced components of head trauma and may prove useful as an intraoperative imaging technique to facilitate surgery in head-injured patients.