Blood pressure is an important parameter for understanding a range of health conditions, from the acute to the chronic. Currently, a sphygmomanometer cuff and an auscultatory technique have been considered as accurate methods to determine the blood pressure, without resorting to invasive methods. However, the use of the sphygmomanometer cuff likely suffers from several shortcomings. For example,                sphygmomanometer cuff generally provides only a non-continuous average blood pressure measurement        measurement can suffer from several systematic sources of error and/or restricted to relatively healthy individuals        measurement can likely only be used to ascertain the blood pressure at a limited number of locations on the body        
Optical Coherence Tomography (“OCT”), including Fourier Domain OCT, including but not limited to Optical Frequency Domain Imaging (“OFDI”), Swept Source Optical Coherence Tomography (“SS-OCT”), and Spectral-Domain Optical Coherence Tomography (“SD-OCT”)—some of which are described in described in International Patent Application PCT/US2004/029148, filed Sep. 8, 2004 which published as International Patent Publication No. WO 2005/047813 on May 26, 2005, U.S. patent application Ser. No. 11/266,779, filed Nov. 2, 2005 which published as U.S. Patent Publication No. 2006/0093276 on May 4, 2006, and U.S. patent application Ser. No. 10/501,276, filed Jul. 9, 2004 which published as U.S. Patent Publication No. 2005/0018201 on Jan. 27, 2005, and U.S. Patent Publication No. 2002/0122246, published on May 9, 2002), can generally utilize low coherence interferometry and/or optical frequency domain interferometry procedures to measure scattering as a function of depth.
If the blood pressure could be accurately and reliably measured using an external optical measurement, it would facilitate a high-speed beat-to-beat variation in the blood pressure to be monitored in a large number of locations on the body, e.g., by inexpert users, in non-clinical settings.
Previously, other concepts/procedures of utilizing non-invasive optical measurements to estimate the blood pressure within a vessel have been described. Such concepts include Photoplethysmography (see Y.-Z. Yoon and G.-W. Yoon, “Nonconstrained Blood Pressure Measurement by Photoplethysmography,” J. Opt. Soc. Korea 10, 91-95 (2006)), laser speckle (see J. Biomed. Opt. 15, 061707 (Nov. 22, 2010); doi:10.1117/1.3505008), etc. However, these procedures generally rely on a detection of morphological changes in arteries caused by pressure waves from cardiac output. Thus, these procedures are dependent on hard-to-estimate quantities, such as, e.g., the elasticity of the arterial wall and other physiological factors. These dependencies limit the practicality of such procedures.
Thus, it may be beneficial to address and/or overcome at least some of the deficiencies of the prior approaches, procedures and/or systems that have been described herein above.