Need more time to optimize the sensor

Traumatic brain injury (TBI) affects 1.7 million people in the United States each year, resulting in 2.5 million emergency department visits, 280,000 hospitalizations, >50,000 deaths, and more than $60 billion in economic cost. TBI also affects >30,000 military personnel annually and almost 8% of veterans who received care between 2001 and 2011. Post-traumatic neurologic outcome depends on the severity of initial injuries and the extent of secondary cerebral damage. Ischemia is the most common and devastating secondary insult. Ischemic brain damage has been identified histologically in ~90% of patients who died following closed head injury, and several studies have associated low cerebral blood flow (CBF) with poor outcome. Specifically, CBF of less than 200 ml/min has been shown to be the critical lower threshold for survival in neurointensive care patients. In addition to intracranial hypertension and cerebral edema, systemic hypotension and reduced cardiac output contribute substantially to posttraumatic cerebral ischemia. Additionally, the carotid artery is the most common site of blunt cerebral vascular injury (BCVI), which may further compromise CBF and cause subsequent death or debilitating stroke. Specifically, high grade internal carotid arterial (ICA) injuries are associated with the highest mortality and stroke rate.

The investigators' goal is to develop of a wearable noninvasive, continuous, automated ultrasound sensor to accurately measure extracranial ICA flow volume. In doing so, the investigators aim to enable early detection of CBF compromise, thereby preventing secondary ischemic injuries in TBI patients. To achieve this goal, the investigators plan to first build a prototype wearable ICA ultrasound senor with integrated signal processing platform, then test its accuracy in an in vitro system and healthy human subjects.

Inclusion Criteria:

• Healthy volunteers
• Age 18 or older

Exclusion Criteria:

• Claustrophobic
• Hyperventilation or panic disorders
• Pregnant
• Have metal implants or cannot pass the MRI screening questions