Analysis of muscle tissue in vivo using fiber-optic autofluorescence and diffuse reflectance spectroscopy

Abstract

. Significance: Current methods for analyzing pathological muscle tissue are time consuming and rarely quantitative, and they involve invasive biopsies. Faster and less invasive diagnosis of muscle disease may be achievable using marker-free in vivo optical sensing methods. Aim: It was speculated that changes in the biochemical composition and structure of muscle associated with pathology could be measured quantitatively using visible wavelength optical spectroscopy techniques enabling automated classification. Approach: A fiber-optic autofluorescence (AF) and diffuse reflectance (DR) spectroscopy device was manufactured. The device and data processing techniques based on principal component analysis were validated using in situ measurements on healthy skeletal and cardiac muscle. These methods were then applied to two mouse models of genetic muscle disease: a type 1 neurofibromatosis (NF1) limb-mesenchyme knockout ( ) and a muscular dystrophy mouse ( mdx ). Results: Healthy skeletal and cardiac muscle specimens were separable using AF and DR with receiver operator curve areas (ROC-AUC) of . AF and DR analyses showed optically separable changes in quadriceps muscle (ROC-AUC >0.97) with no differences detected in the heart (ROC-AUC <0.67), which does not undergo gene deletion in this model. Changes in AF spectra in mdx muscle were seen between the 3 week and 10 week time points (ROC-AUC = 0.96) and were not seen in the wild-type controls (ROC-AUC = 0.58). Conclusion: These findings support the utility of in vivo fiber-optic AF and DR spectroscopy for the assessment of muscle tissue. This report highlights that there is considerable scope to develop this marker-free optical technology for preclinical muscle research and for diagnostic assessment of clinical myopathies and dystrophies.

Polymer coatings with rare-earth activated phosphors for optical fiber fluorosensors

“…In addition, visible autofluorescence is seemingly safer to operate with, and the costs associated with equipment for excitation and detection (e.g. light sources and detectors) are lower than those required for UV autofluorescence 8 . Nevertheless, multiple fluorophores emit in the UV region 9 , e.g.…”

A combined autofluorescence and diffuse reflectance spectroscopy for mucosa tissue diagnosis: Dual‐distance system and data‐driven decision

“…For example, autofluorescence (AF) spectroscopy, reflecting the perturbed concentrations of nicotinamide adenine dinucleotide and flavin adenine dinucleotide in mucosal tissue, provides an index for tissue metabolism. Diffuse reflectance (DR) spectroscopy can also be used as biomarker for detecting the spectroscopy variation in mucosa lesions [12][13][14][15][16][17][18][19]. However, as for rapidly screening programs, these techniques still have the limitations [20][21][22][23][24]: (1) most studies only provide channels with single source-detector-separation (SDS), which fail to gather depth-resolved information and thus affect classification accuracy; (2) many relay on subjective visual impressions for abnormality identification; (3) some only gather DR information, and may induce wrong results in some conditions, that is, inflammatory and cancerous tissues; (4) some CCD-integrated devices can provide the DR/AF images for enhanced performance, but accompanied by high-cost limitation.…”