Laser Technology Mobilizes Head Trauma Assessment

The decisions made about patient care in the hour following a traumatic brain injury (TBI) are critical to patient outcome. A hand-held diagnostic device to assess the severity of the injury immediately, at the point of care, could make the difference between a successful outcome or irreversible brain damage following a TBI.

To enable timely intervention, researchers at the University of Birmingham are developing a portable noninvasive diagnostic to quickly measure the extent of cerebral injury. The device uses Raman spectroscopy and fundus imaging of the neuroretina to rapidly acquire a molecular footprint of the TBI biochemistry.

The EyeD device combines modified optics with imaging of the optic nerve, which is done with a class I, eye-safe laser that is introduced into the optical path. EyeD permits Raman spectroscopy and fundus imaging to occur simultaneously by isolating the Raman and white light paths.

Researchers at the University of Birmingham are developing a hand-held device for use in the critical ‘golden hour’ after a traumatic brain injury, when decisions about treatment are crucial to a favorable outcome. Courtesy of University of Birmingham.

The device collects Raman signals using a detector. It classifies data using an artificial neural network algorithm as a decision support tool and a self-optimizing index network as a framework for multivariate analysis. These features enable EyeD to provide dimensionality reduction, feature extraction, and multiclass classification at the same time.

The optic nerve and the brain carry the same biomarkers. Even the smallest change in these biomarkers can indicate a significant change in brain health. EyeD scans the back of the eye, where the optic nerve sits, and detects and analyzes the composition and balance of the biomarkers after TBI. It assesses changes to the biomarkers, which indicate injury to the brain, and provides information on the level of severity.

For head injuries that occur, for example, on the field during contact sports or after motor vehicle accidents, there is currently no point-of-care technology available to quantitatively assess TBI with enough sensitivity to determine its severity and form an early diagnosis. Since even mild TBI and concussion can have cumulative effects, it is crucial to evaluate the injury and decide on treatment as soon after it occurs as possible.

“Early diagnosis of TBI is crucial, as life-critical decisions on treatment must be made within the first ‘golden hour’ after injury,” professor Pola Goldberg Oppenheimer said. “However, current diagnostic procedure relies on observation by ambulance crews and MRI or CT scans at a hospital, which may be some distance away.”

A measurement of abnormal changes in the optic nerve at the point of care would provide a quantitative assessment of trauma at the earliest stages and guide treatment and triaging without delay.

The research team led by Oppenheimer previously showed that Raman spectroscopy could be used to detect mild TBI from the retina and brain in a murine model using a 785-nm excitation laser. The team also formed a classification model using a commercial Raman spectrometer in the fingerprint region. High-wave number measurements recorded from these murine tissue samples displayed a clear separation between healthy controls and TBI groups.

To provide a controlled testing environment with fixed optics, the researchers developed a tissue phantom that mimics the physical dimensions and optical characteristics of the eye, while providing a realistic Raman signature of the retina.

The researchers used the phantom eye to test the device’s alignment and ability to focus on the back of the eye. Using animal tissue, they tested whether the device could discern between TBI and non-TBI states. They analyzed a porcine ex vivo eye retina, which is similar to the human eye in size, structure, development, and composition.

The researchers said that the EyeD device is now ready for further evaluation, including clinical feasibility and efficacy studies and patient acceptability studies.

The team expects the noninvasive diagnostic device to be developed into a cost-effective, portable technology that will be suitable for use at the point of care to rapidly determine whether TBI has occurred and classify the injury as mild, moderate, or severe so that triage can be directed appropriately and in a timely manner.

The research was published in Science Advances (www.doi.org/10.1126/sciadv.adg5431).