Significance: Current systems for diffuse optical tomography (DOT) are unsuitable for clinical applications on acute traumatic brain injury (TBI) patients while in the intensive care unit (ICU). Aim: To develop and test a method for DOT recordings suitable for TBI patients in the ICU. This method is based on measurements and co-registration using 3-D optical scans, and the acquisition of optical data using a custom-made helmet which would enable a multimodal (invasive and non-invasive) neuromonitoring. Approach: Probe displacements compared to electromagnetic digitization co-registrations were assessed. The capacity to isolate and monitor, using functional near-infrared spectroscopy (fNIRS), the optical signal in the intracranial (ICT) and extracranial tissues (ECT) was tested on 23 healthy volunteers. Participants were scanned with a frequency-domain NIRS device (690 and 830 nm) during 5 Valsalva maneuvers (VM) in a simulated ICU environment. Results: The results showed an average error in probe displacement of 5.5 mm, a sufficient capacity to isolate oxyhemoglobin O2Hb (p=6.4E10-6) and total hemoglobin HbT (p=2.8E10-5 27 ) in the ICT from the ECT, and to follow the changes of hemoglobin in the ICT during the VM (O2Hb, p=9.2E10-4; HbT, p=1.0E10-3). Conclusions: The developed approach appears to be suitable for use on TBI patients in the ICU.

The authors have declared no competing interest.

This article presents independent research funded by the National Institute for Health Research Surgical Reconstruction and Microbiology Research Centre (NIHR SRMRC), partnership between University Hospitals Birmingham NHS Foundation Trust, the University of Birmingham, and the Royal Centre for Defence Medicine. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

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