A portable device that covers the head and uses microwave technology to examine brain tissue in prehospital settings could cut the time it takes to evaluate brain injuries. So conclude researchers after evaluating their “microwave helmet” in a small trial.

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Researchers suggest that their microwave helmet could cut the triage time for brain injuries.
Image credit: Bold/Chalmers University of Technology

The researchers – including members from Chalmers University of Technology and Sahlgrenska University Hospital, both in Gothenburg, Sweden – report their findings in the Journal of Neurotrauma.

They suggest that the results of their small trial show that microwave technology can be used for the rapid detection of intracranial bleeding that can result from head injuries.

First author Dr. Johan Ljungqvist, a specialist in neurosurgery at the Sahlgrenska University Hospital, says: “The microwave helmet could improve the medical assessment of traumatic head injuries even before the patient arrives at the hospital.”

He notes that even though their study was small, and they only focused on one type of head injury, “the result indicates that the microwave measurements can be useful in ambulances and in other care settings.”

In their study paper, he and his colleagues note that microwave technology has already been evaluated for other medical applications – such as distinguishing between strokes caused by blood clots and strokes caused by bleeding in the brain.

Traumatic brain injury (TBI) is disruption of normal brain function due to trauma that results from an injury that bumps, jolts, hits, or penetrates the head. The severity of trauma ranges from “mild” (the most common kind, also known as concussion) to “severe.”

Fast facts about TBI
  • In the U.S. between 2006 and 2010, TBI-related deaths were highest in people aged 65 and older
  • Over that period, vehicle crashes were the leading cause of TBI-related deaths for young people aged between 5 and 24
  • Among nonfatal TBI-related injuries, rates of ED visits were highest for children aged 4 and under.

Learn more about TBI

TBI can disrupt memory, thinking, movement, vision, hearing, and emotional functioning. It can also result in personality changes and depression. The effects are not confined to individuals; they can also impact families, friends, and communities.

TBI is a major cause of death and disability in the United States, where estimates from the Centers for Disease Control and Prevention (CDC) suggest that 138 people die every day from injuries that include TBI.

The majority of TBI survivors experience effects that last a few days, while others are left with enduring disabilities that can last for the rest of their lives.

In the U.S. in 2010, the amount of visits to emergency departments (EDs), admissions to hospitals, and deaths either related to TBI alone or to TBI linked with other injuries totaled around 2.5 million.

CDC figures for between 2006 and 2010 show falls as the leading cause of TBI (accounting for 40.5 percent of ED visits, hospitalizations, and deaths), followed by unintentional blunt trauma (15.5 percent), and motor vehicle crashes (14.3 percent).

Dr. Ljungqvist and colleagues note that the key to improving outcomes for people who sustain TBIs is to reduce the time it takes from when the injury occurs to deciding the right treatment.

The microwave helmet has three parts: a helmet incorporating microwave antennae that is placed on the patient’s head; a microwave signal generator; and a computer that controls the equipment, collects the data, and processes them through advanced mathematical algorithms.

The microwave generator sends signals through transmit antennae in the helmet into the patient’s brain.

Receiving antennae in the helmet pick up the signals after they have been scattered by and reflected from the brain tissue.

The advanced algorithms analyze the complex patterns in the microwave signals to deduce what they might indicate about changes in the brain.

Dr. Ljungqvist and colleagues evaluated the ability of their microwave technology to differentiate between people with brain bleeds due to injury and people without brain injury.

The team tested the device on 20 patients with traumatic intracranial hematomas, 20 patients with chronic subdural hematoma, and 20 healthy volunteers. The patients were hospitalized for surgery in a Swedish hospital.

The participants also underwent traditional scanning with computerized tomography (CT). The CT scan results were then compared with the microwave helmet results.

The authors conclude that the microwave technology “shows promise as a tool to improve triage accuracy.” It detected the hematomas at 100 percent sensitivity and 75 percent specificity.

Sensitivity indicates how well a test rules out disease, and specificity indicates how well it rules it in. Thus, in this study, the microwave helmet “over-diagnosed” 25 percent of the cases (that is, 25 percent were “false positives.”)

The researchers note that plans are already in place to test the microwave helmet with more acute head injury patients in Sweden and other countries.

Microwave technology has the potential to revolutionize medical diagnostics by enabling faster, more flexible, and more cost-effective care.”

Mikael Persson, professor of biomedical engineering, Chalmers University of Technology

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