Over the last 30 years significant progress has been made in the fields of hemodynamics and hemorheology, spurred on by innovative developments in measurement techniques [1] and instrumentation [2-3]. Measurements obtained via these methods have been used for monitoring hemodynamic phenomena and diagnosing circulatory disorders, thus providing a deeper understanding of hemodynamic-related diseases in humans [4].

Understanding of hemodynamics was greatly enhanced by Poiseuille (1799-1869), who developed a relation between flow rate and pressure (Poiseuille's law). The most frequently measured parameters in hemodynamics are blood flow rate and blood pressure, and thus one can calculate resistance to flow as the ratio of pressure to flow. Of course, this resistance concept is a “black box” approach in which all of the parameters that affect resistance are lumped together. For in vitro studies of flow in single tubes or networks, it is rather straightforward to define and measure such parameters (e.g., diameter, viscosity, length) and to understand their interrelations. Conversely, it is difficult to measure the in-vivo hemodynamic parameters. Recently, however, developments in optics and electronics have resulted in various techniques for measuring these hemodynamic parameters, with some techniques commercially available. The objective of this chapter is to introduce the principles and application of conventional and new techniques for laboratory and clinical measurements of hemodynamic parameters.