Recent advances in high speed diffuse optical imaging in biomedicine

Abstract

Diffuse optical imaging (DOI) is a label-free, safe, inexpensive, and quantitative imaging modality that provides metabolic and molecular contrast in tissue using visible or near-infrared light. DOI modalities can image up to several centimeters deep in tissue, providing access to a wide range of human tissues and organ sites. DOI technologies have benefitted from several decades of academic research, which has provided a variety of platforms that prioritize imaging depth, resolution, field-of-view, spectral content, and other application-specific criteria. Until recently, however, acquisition and processing speeds have represented a stubborn barrier to further clinical exploration and implementation. Over the last several years, advances in high-speed data acquisition enabled by high-speed digital electronics, newly available sources and detectors, and innovative new scanning methods have led to major improvements in DOI rates. These advances are now being coupled with new data processing algorithms that utilize deep learning and other computationally efficient methods to provide rapid or real-time feedback in the clinic. Together, these improvements have the potential to help advance DOI technologies to the point where major impacts can be made in clinical care. Here, we review recent advances in acquisition and processing speed for several important DOI modalities.

Multitask Deep Learning Reconstruction and Localization of Lesions in Limited Angle Diffuse Optical Tomography

“…6-Analytical). Our DOT reconstruction model is mainly interested in the absorption parameter changes as it is related to the hemoglobin concentration changes that mark the presence of anomalies [4]. Similar results are obtained for MLP with very low per pixel values of reconstructed absorption coefficients (Fig.…”

Modulation frequency selection and efficient look-up table inversion for frequency domain diffuse optical spectroscopy

“…Although most biological phenomena happen significantly more slowly than 1 kHz, high-speed measurements can be used to rapidly image large volumes of tissue. 28 One problem identified in a recent multi-center clinical trial of FD-DOS was poor data quality necessitating the removal of some patients from the analysis. 2 High-speed OP extractions could enable real-time visualization of tissue contrast which would allow the operator to ensure that high-quality data were being collected.…”

Recent Developments in Instrumentation of Functional Near-Infrared Spectroscopy Systems

“…2012 [28] Diffuse optical imaging instrumentation 2014 [29] DOT image reconstruction algorithms and its clinical applications 2016 [30] Basics of FD-NIRS and its application to functional brain studies 2020 [31] Recent advances in acquisition and processing speed for several Diffuse Optical Imaging (DOI) modalities. 2020 [32] TD-fNIRS Basic features of the TD approach and diffuse optics 2016 [33] Theoretical background, instruments, advanced theories and methods 2019 [14] Brain monitoring clinical applications 2019 [15] Time-gated detection modality 2020 [13] However, most of the reviews have been focusing on the differences among these three techniques and their applications rather than the instrumentation of such systems. Therefore, the main goal of this paper is to remedy this gap by examining the main differences and similarities between the CW, TD, and FD techniques in building the fNIRS system from an instrumentation point of view.…”