Accuracy of homogeneous models for photon diffusion in estimating neonatal cerebral hemodynamics by TD-NIRS.

Caterina Amendola,Lorenzo Spinelli,Monica Fumagalli,Cesare Martinelli,Davide Contini,Agnese De Carli,Alessandro Torricelli

doi:10.1364/boe.417357

Caterina Amendola, Lorenzo Spinelli + Show 5 more

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https://doi.org/10.1364/boe.417357

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Abstract

We assessed the accuracy of homogenous (semi-infinite, spherical) photon diffusion models in estimating absolute hemodynamic parameters of the neonatal brain in realistic scenarios (ischemia, hyperoxygenation, and hypoventilation) from 1.5 cm interfiber distance TD NIRS measurements. Time-point-spread-functions in 29- and 44-weeks postmenstrual age head meshes were simulated by the Monte Carlo method, convoluted with a real instrument response function, and then fitted with photon diffusion models. The results show good accuracy in retrieving brain oxygen saturation, and severe underestimation of total cerebral hemoglobin, suggesting the need for more complex models of analysis or of larger interfiber distances to precisely monitor all hemodynamic parameters.

Highlights

Brain injuries are an important cause of morbidity and mortality in neonates
In all cases the estimated reduced scattering coe cient shows an underestimation with respect to the nominal values (Fig. 4), and that is more evident in case of 29 weeks postmenstrual age (PMA) mesh
In this work we studied the sensitivity of TD-Near Infrared Spectroscopy (NIRS) in assessing neonatal brain hemodynamic parameters, when homogenous models of analysis are employed

Summary

Introduction

Brain injuries are an important cause of morbidity and mortality in neonates. Cerebrovascular disturbances, such as impaired cerebral hemodynamics and autoregulation (CA), are involved in the pathogenesis of brain injury [1,2,3,4]. Transcranial Doppler ultrasound is widely used in neonatology to measure cerebral blood flow velocity in target artery, but its results are limited to the macro-vasculature [13], and in particular clinical derangement the macro-vasculature blood flow may not reflect the one in cerebral region [14]. It is operator-dependent [15] and it does not allow continuous monitoring cerebral hemodynamic parameters. Near Infrared Spectroscopy (NIRS) appears to be an interesting alternative: it is a non-invasive technique which allows for monitoring brain hemodynamics and CA, at bed side [16,17]

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