title: Implicit and explicit prior information in near-infrared spectral imaging: accuracy, quantification and diagnostic value.
abstract: Near-infrared spectroscopy (NIRS) of tissue provides quantification of absorbers, scattering and luminescent agents in bulk tissue through the use of measurement data and assumptions. Prior knowledge can be critical about things such as (i) the tissue shape and/or structure, (ii) spectral constituents, (iii) limits on parameters, (iv) demographic or biomarker data, and (v) biophysical models of the temporal signal shapes. A general framework of NIRS imaging with prior information is presented, showing that prior information datasets could be incorporated at any step in the NIRS process, with the general workflow being: (i) data acquisition, (ii) pre-processing, (iii) forward model, (iv) inversion/reconstruction, (v) post-processing, and (vi) interpretation/diagnosis. Most of the development in NIRS has used ad hoc or empirical implementations of prior information such as pre-measured absorber or fluorophore spectra, or tissue shapes as estimated by additional imaging tools. A comprehensive analysis would examine what prior information maximizes the accuracy in recovery and value for medical diagnosis, when implemented at separate stages of the NIRS sequence. Individual applications of prior information can show increases in accuracy or improved ability to estimate biochemical features of tissue, while other approaches may not. Most beneficial inclusion of prior information has been in the inversion/reconstruction process, because it solves the mathematical intractability. However, it is not clear that this is always the most beneficial stage.
authors: Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA. brian.w.pogue@dartmouth.edu
authors: Brian W
authors: BW
authors: Pogue
authors: Scott C
authors: SC
authors: Davis
authors: Frederic
authors: F
authors: Leblond
authors: Michael A
authors: MA
authors: Mastanduno
authors: Hamid
authors: H
authors: Dehghani
authors: Keith D
authors: KD
authors: Paulsen
mesh_terms: D001703:Biophysics / Q000379:methods; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology; D003952:Diagnostic Imaging / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008962:Models, Theoretical; D009369:Neoplasms / Q000473:pathology; D055095:Optics and Photonics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D005456:Fluorescent Dyes