In this work, we discuss data acquired in a clinical investigation to evaluate the utility of transcranial ultrasound for monitoring/detecting brain injury. Using a portable ultrasonic data acquisition system, over one thousand transcranial waveforms were captured from five subjects, including three head-injured patients. Several representative waveforms are shown to demonstrate the feasibility of the ultrasonic detection scheme and to illustrate the similarities and variabilities among the signals acquired in this study. © 2002 SPIE · 0277-786X/01/$15.00.