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

SignificanceInvasive neuromonitoring hinders the application of diffuse optical tomography (DOT) to critically ill adults in the intensive care unit (ICU).AimWe 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.ApproachCoregistration 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.ResultsThe results showed an average error of coregistration of 5.5 mm and a sufficient capacity to isolate oxyhemoglobin (O2Hb) (p=6.4·10−6) and total hemoglobin (HbT) (p=2.8·10−5) in the ICT from the ECT and to follow the changes of hemoglobin in the ICT during the VM (O2Hb, p=9.2·10−4; HbT, p=1.0·10−3).ConclusionThe developed approach appears to be suitable for use on TBI patients in the ICU in a multimodal monitoring.