The left ventricular color M-mode Doppler flow propagation velocity V(p): in vivo comparison of alternative methods including physiologic implications.

Three alternative methods have been proposed for determining the "velocity of propagation" (V(p)) from color M-mode Doppler transmitral flow images. A quantitative intermethod comparison is performed by using a broad class of images encountered in clinical practice. V(p) for 13 subjects was measured by using each of the 3 methods and then statistically compared. Differences among the definitions of V(p) generated large differences in its numerical value when computed from the same image. Depending on the choice of method, the value of V(p) can vary by as much as 250%. Advantages and limitations of each method are discussed in the context of the physical meaning of V(p). Development of an optimal version of V(p) and consensus on how it should be defined merits further attention. This will require a multidisciplinary approach encompassing physiology, fluid dynamics, image processing, and mathematical modeling.