Journal Article

Validating a new methodology for optical probe design and image registration in fNIRS studies

Boas, David A., Spencer, John P., Bohache, Kevin, Wijeakumar, Sobanawartiny, Magnotta, Vincent A.

2015

Overview

Functional near-infrared spectroscopy (fNIRS) is an imaging technique that relies on the principle of shining near-infrared light through tissue to detect changes in hemodynamic activation. An important methodological issue encountered is the creation of optimized probe geometry for fNIRS recordings. Here, across three experiments, we describe and validate a processing pipeline designed to create an optimized, yet scalable probe geometry based on selected regions of interest (ROIs) from the functional magnetic resonance imaging (fMRI) literature. In experiment 1, we created a probe geometry optimized to record changes in activation from target ROIs important for visual working memory. Positions of the sources and detectors of the probe geometry on an adult head were digitized using a motion sensor and projected onto a generic adult atlas and a segmented head obtained from the subject's MRI scan. In experiment 2, the same probe geometry was scaled down to fit a child's head and later digitized and projected onto the generic adult atlas and a segmented volume obtained from the child's MRI scan. Using visualization tools and by quantifying the amount of intersection between target ROIs and channels, we show that out of 21 ROIs, 17 and 19 ROIs intersected with fNIRS channels from the adult and child probe geometries, respectively. Further, both the adult atlas and adult subject-specific MRI approaches yielded similar results and can be used interchangeably. However, results suggest that segmented heads obtained from MRI scans be used for registering children's data. Finally, in experiment 3, we further validated our processing pipeline by creating a different probe geometry designed to record from target ROIs involved in language and motor processing. •New processing pipeline was developed for creating optimal and scalable probe geometry for fNIRS.•Probe geometry was created for an adult head and a child's head for investigating visual working memory.•At least 17 regions of interest intersected with channels from adult and child probe geometries.•Processing pipeline was validated for another study investigating motor and language functions.

• Publisher: Elsevier Inc,Elsevier Limited
• Subject: AtlasViewerGUI / Connectome - instrumentation / Connectome - methods / Equipment Design / Equipment Failure Analysis / Experiments / Functional near infrared spectroscopy / Geometry / Humans / Light / Medical imaging / Memory, Short-Term - physiology / NMR / Nuclear magnetic resonance / Optical Devices / Optode co-registration / Pattern Recognition, Visual - physiology / Pipelines / Probe geometry / Reproducibility of Results / Sensitivity and Specificity / Sensors / Spectroscopy, Near-Infrared - instrumentation / Spectroscopy, Near-Infrared - methods / Subtraction Technique - instrumentation / Transducers / Visual Cortex - physiology / Visual working memory