Stroke is the third-leading cause of death in the U.S. and the leading cause of disability. While some 1.5 million people in the US report stroke-like symptoms annually, half of them have actually not suffered a stroke. Making a reliable assessment of stroke in just minutes would provide timely information for treating the victims faster, at lower cost, and with less risk. Jan Medical developed the first and so far the only portable brain sensing device for rapid detection of ischemic stroke. The device is aimed to be used in the ER or ambulance, before a thorough evaluation can be made in a hospital setting with a CT or MRI. The device operation is based on an interesting principle of detecting the ultrasonic waves emitted by the skull. The device does not measure back-reflection of the emitted ultrasound from the brain; instead, it measures natural mechanical vibrations of the skull. These vibrations are generated by a pressure wave of blood rushing from the heart toward the skull during each pulse. In 5 minutes, the device collects enough information to detect a variety of cerebrovascular anomalies: an intracerebral or subarachnoid hemorrhage, epidural or subdural hematoma, intracranial aneurysm, arteriovenous malformations, ischemic stroke, or transient ischemic attack. The device consists of two primary components: a headset with sensors and a controller for decoding the collected ultrasonic information connected to a computer. Jan Medical markets its device primarily for early detection of stroke as well as the traumatic brain injury, such as sports-related concussion that is often not detected on the field leaving it to a discretion of a team physician to clear the player for return to the game. The device can also be used for rapid military diagnostics of traumatic brain injury at the battlefield.