High density functional diffuse optical tomography based on frequency domain measurements improves image quality and spatial resolution

Research output: Contribution to journalArticle

Colleges, School and Institutes

External organisations

  • Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA

Abstract

Measurements of dynamic Near Infrared (NIR) light attenuation across the human head together with model-based image reconstruction algorithms allow the recovery of three-dimensional spatial brain activation maps. Previous studies using high-density diffuse optical tomography (HD-DOT) systems have reported improved image quality over sparse arrays. These HD-DOT systems incorporated multi-distance overlapping continuous wave measurements that only recover differential intensity attenuation. In this study, we investigate the potential improvement in reconstructed image quality due to the additional incorporation of phase shift measurements, which reflect the time-of-flight of the measured NIR light, within the tomographic reconstruction from high-density measurements. To evaluate image reconstruction with and without the additional phase information we simulated point spread functions across a whole-scalp field of view in 24 subject specific anatomical models using an experimentally derived noise model. The addition of phase information improves the image quality by reducing localization error by up to 59% and effective resolution by up to 21% as compared to using the intensity attenuation measurements alone. Furthermore, we demonstrate that the phase data enable images to be resolved at deeper brain regions where intensity data fails, which is further supported by utilizing experimental data from a single subject measurement during a retinotopic experiment.

Details

Original languageEnglish
Article number035007
Number of pages28
JournalNeurophotonics
Volume6
Issue number3
Publication statusPublished - 21 Aug 2019

Keywords

  • Frequency Domain, High Density Diffuse Optical Tomography, Functional Near Infrared Imaging