Diffuse optical tomography system for acute traumatic brain injury in the intensive care unit: a prospective study on healthy volunteers

Significance: Invasive neuromonitoring hinders the application of diffuse optical tomography (DOT) to critically ill adults in the intensive care unit (ICU). Aim: We aim to develop and test a method for DOT recordings suitable for traumatic brain injury (TBI) patients in the ICU. This method is based on measurements and coregistration using a 3D optical scan and the acquisition of optical data using a custom-made helmet, which would enable a multimodal (invasive and noninvasive) neuromonitoring. Approach: Coregistration accuracy between the method based on a 3D optical scan and one based on an electromagnetic digitization, the latter considered to be the gold standard, was assessed. The capacity to isolate and monitor, using functional near-infrared spectroscopy, 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 of coregistration of 5.5 mm and a sufficient capacity to isolate oxyhemoglobin ( formula presented ) ( formula presented ) and total hemoglobin (HbT) ( formula presented ) in the ICT from the ECT and to follow the changes of hemoglobin in the ICT during the VM ( formula presented ; HbT, formula presented ). Conclusion: The developed approach appears to be suitable for use on TBI patients in the ICU in a multimodal monitoring.