Patent ID: 8886294
Filing Date: 2014-11-11
Classification: A61B

Abstract:
1. A method for determining a physiological parameter of a subject, the method comprising: detecting a first acoustic pressure signal and a second acoustic pressure signal using one or more acoustic detectors, wherein the first acoustic pressure signal and the second acoustic pressure signal are caused by absorption of at least some of one or more photonic signals by one or more constituents in a first blood vessel and in a second blood vessel, respectively, and wherein the first acoustic pressure signal and the second acoustic pressure signal comprise dilution responses corresponding to an indicator; deriving a first photoacoustic signal from the first acoustic pressure signal and a second photoacoustic signal from the second acoustic pressure signal; comparing the first photoacoustic signal to the second photoacoustic signal to determine a shape difference or a time difference between the first and second photoacoustic signals; determining whether the first blood vessel or the second blood vessel is an artery or a vein based at least in part on the shape difference or the time difference; selecting the first photoacoustic signal or the second photoacoustic signal based at least in part on the determination of whether the first blood vessel or the second blood vessel is the artery or the vein; and determining the physiological parameter based at least in part on the selected first photoacoustic signal or the second photoacoustic signal.