# Finite Element Modeling of Abdominal Near‐Infrared Spectroscopy for Infant Splanchnic Oximetry

## TL;DR

This study uses computer modeling to find the best sensor design for measuring oxygen levels in infants' abdominal organs using near-infrared light.

## Contribution

A finite element method is introduced to evaluate and optimize NIRS sensor designs for infant splanchnic oximetry.

## Key findings

- Optimal source–detector distances for NIRS sensors are between 4 and 5 cm.
- Sensitivity to intestinal tissue is higher than to superficial adipose tissue at these distances.
- FE modeling enables rapid evaluation of sensor designs for infant splanchnic oximetry.

## Abstract

Abdominal near‐infrared spectroscopy (NIRS) holds promise for early detection of necrotizing enterocolitis and other infant pathologies prior to irreversible injury, but the optimal NIRS sensor design is not well defined. In this study, we develop and demonstrate a computational method to evaluate NIRS sensor designs for infant splanchnic oximetry. We used a finite element (FE) approach to simulate near‐infrared light transport through a 3D model of the infant abdomen constructed from computed tomography (CT) images. The simulations enable the measurement of the contrast‐to‐noise ratio (CNR) for splanchnic oximetry, given a specific NIRS sensor design. A key design criterion is the sensor's source–detector distance (SDD). We calculated the CNR as a function of SDD for two sensor positions near the umbilicus. Contrast‐to‐noise was maximal at SDDs between 4 and 5 cm, and comparable between sensor positions. Sensitivity to intestinal tissue also exceeded sensitivity to superficial adipose tissue in the 4–5 cm range. FE modeling of abdominal NIRS signals provides a means for rapid and thorough evaluation of sensor designs for infant splanchnic oximetry. By informing optimal NIRS sensor design, the computational methods presented here can improve the reliability and applicability of infant splanchnic oximetry.

In this study, we developed a computational method to evaluate near‐infrared spectroscopy sensor designs for infant splanchnic oximetry. We used a finite element model to simulate near‐infrared light transport through a 3D model of the infant abdomen, and calculated contrast‐to‐noise ratio (CNR) as a function of source–detector distance (SDD) to measure sensor performance. Our results suggested that SDDs between 4 and 5 cm optimize CNR and thus may be optimally suited for splanchnic oximetry.