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Background: Functional near-infrared spectroscopy (fNIRS) and functional MRI (fMRI) are non-invasive techniques used to relate activity in different brain regions to certain tasks. Respiratory calibration of the blood oxygen level dependent (BOLD) signal, and combined fNIRS-fMRI approaches have been used to quantify physiological subcomponents giving rise to the BOLD signal. A comparison of absolute oxygen metabolism parameters between MRI and NIRS, using spatially resolved (SRS) NIRS and respiratory calibrated MRI, could yield additional insight in the physiology underlying activation., Materials and Methods: Changes in the BOLD signal, cerebral blood flow (CBF), and oxygen saturation (SO2) were derived from a single MRI sequence during a respiratory challenge in healthy volunteers. These changes were compared to SO2 obtained by a single probe SRS NIRS setup. In addition, concentration changes in oxygenated (O2Hb), deoxygenated (HHb), and total haemoglobin (tHb), obtained by NIRS, were compared to the parameters obtained by MRI., Results: NIRS SO2 correlated with end-tidal CO2 (0.83, p<0.0001), the BOLD signal (0.82, p<0.0001), CBF (0.85, p<0.0001), and also MRI SO2 (0.82, p<0.0001). The BOLD signal correlated with NIRS HHb (-0.76, p<0.0001), O2Hb (0.41, p=0.001), and tHb (r=0.32, p=0.01)., Conclusions: Good correlations show that changes in cerebral physiology, following a respiratory challenge, go hand in hand with changes in the BOLD signal, CBF, O2Hb, HHb, NIRS SO2, and MRI SO2. Out of all NIRS derived parameters, the SO2 showed the best correlation with the BOLD signal., (© 2013 Elsevier Inc. All rights reserved.)

Background: In preterm infants with respiratory distress syndrome (RDS) nasal continuous positive airway pressure (nCPAP) with the "InSurE" procedure (intubation, surfactant, extubation) is increasingly used. However, its effect on cerebral oxygenation and brain function is not known., Objective: To evaluate the effects of the "InSurE" procedure in infants with RDS on regional cerebral oxygen saturation (rScO(2)) and relative cerebral fractional tissue oxygen extraction (cFTOE) using near infrared spectroscopy and on electrical brain activity using amplitude-integrated electroencephalography (aEEG)., Methods: Sixteen infants with RDS, treated with the "InSurE" procedure, and 16 matched controls with nCPAP, were monitored for mean arterial blood pressure (MABP), arterial oxygen saturation (SaO(2)), rScO(2), cFTOE and aEEG. Ten-minute periods were selected and averaged at 120 and 20 minutes before, during the procedure and at 30 minutes, 1, 2, 6, 12 and 24 h after the start of the "InSurE" procedure. aEEG was analysed by quantitative and qualitative (Burdjalov score) methods., Results: MABP was not different between groups on all time points. rScO(2) and cFTOE were comparable between groups, but there was a trend towards lower rScO(2) and higher cFTOE 30 minutes after opioid administration in the "InSurE" infants compared with controls (62% (SD 11) vs 68% (SD 10) and 0.30 (SD 0.10 ) vs 0.28 (SD 0.11), respectively). aEEG amplitudes and Burdjalov scores were significantly lower in "InSurE" infants from 30 minutes after opioid administration up to 24 h after the start of the procedure (p<0.05)., Conclusion: In the present study, the "InSurE" procedure did not induce perturbation of cerebral oxygen delivery and extraction, whereas electrical brain activity decreased for a prolonged period of time.