Broadband optical spectroscopy of the human adipose and muscle tissues: an in-vivo pilot study

The ability to non-invasively monitor in-vivo the human muscle and adipose tissue is of great practical use and hence of growing interest in the fields of clinical diagnostics and preventive medicine. Optical methods, such as diffuse optical spectroscopy (DOS) applied in the near-infrared spectral region could be of great interest in clinical scenario. In this work, we present a pilot study based on multi-distance broadband time-domain diffuse optical spectroscopy (TD DOS) to characterize in vivo the subcutaneous adipose tissue (abdominal region) and the vastus lateralis muscle (thigh region). The study was performed using a fully automated portable TD DOS instrument on a set of 24 healthy adult volunteers. The optical properties of these two tissue types were obtained over the broad wavelength range of 600-1100 nm. The results suggest a clear influence of the stratified nature of the two regions considered, namely the abdomen and thigh, on the recovered optical properties. This work demonstrates how multi-distance broadband diffuse optical spectroscopy could be complimentary in fields like the non-invasive spectroscopy of adipose tissue and the standard DOS-based muscle oximetry.