Combined pulse oximetry and diffusing wave spectroscopy system and control method therefor

An integrated device for analyzing tissue, comprising:

• a pulse oximeter having two or more light sources and two or more optical detectors, the light sources configured to irradiate a tissue sample with a light of first wavelength and a light of second wavelength, and the optical detectors configured to detect intensities of the light of first wavelength and the light of second wavelength transmitted through the tissue sample;
• a pulse wave measuring apparatus configured to measure temporal intensity fluctuations of one of the light of first wavelength and the light of second wavelength transmitted through the tissue sample;
• and
• a processor operatively connected to the pulse oximeter and the pulse wave measuring apparatus, the processor configure to:
• calculate, using the temporal intensity fluctuations, an intensity autocorrelation function and a decay time of the autocorrelation function, and generate a time-series signal of the decay time of the intensity autocorrelation function;
• calculate a power spectrum of the time-series signal of the decay time and to detect peaks of the power spectrum;
• calculate a blood flow value in the tissue sample by using the temporal intensity fluctuations and the peaks of the power spectrum;
• and
• calculate an oxygen saturation value within the tissue sample from a ratio of the intensities of the light of first wavelength and the light of second wavelength transmitted through the tissue sample.

A method for analyzing tissue with an integrated device, comprising:

• irradiating a tissue sample with two or more light sources emitting a light of first wavelength and a light of second wavelength different from the first wavelength;
• detecting, with two or more detectors, an intensity of the light of first wavelength and an intensity of the light of second wavelength transmitted through the tissue sample;
• processing, using a processor, electrical signals output from the two or more detectors to quantify the intensity of the light of first wavelength and the intensity of the light of second wavelength transmitted through the tissue sample, and processing one electrical signal output from one the two or more detectors to quantify temporal intensity fluctuations in one of the light of first wavelength and the light of second wavelength transmitted through the tissue sample, and
• calculating, based on the intensity of the light of first wavelength and the intensity of the light of second wavelength transmitted through the tissue sample, one or more of an oxygen saturation value, and a blood flow value within the tissue sample.

A system, comprising:

• a first source-detector pair including a first light source and a first detector, the first light source configured to irradiate tissue of a subject with light of a first wavelength;
• a second source-detector pair including a second light source and a second detector, the second light source configured to irradiate the tissue with light of a second wavelength different from the first wavelength;
• a correlator configured to calculate an intensity autocorrelation function by using light intensity data corresponding to light intensity fluctuations detected by one of the first detector and the second detector, and to derive a time decay function of the intensity autocorrelation function;
• a spectrum analyzer configured to obtain a spectrum of the time decay function, and to select a peak value of the spectrum;
• a filter configure to, using the peak value of the spectrum, filter first and second electric signals respectively output from the first and second detectors;
• and
• a processor configured to calculate one or more of an oxygen saturation value, and a blood flow value of the tissue sample using the filtered first and second electric signals.