Direction, site of origin and duration of jets: implications in the color Doppler assessment of valvar lesions. With emphasis on pure and combined mitral and bicuspid aortic lesions.

Color Doppler imaging has renewed and widened the capabilities of the flow mapping technique. In addition to its facilitation, it has some specific advantages: by showing the spatio-temporal variations of jets within the cardiac cycle, it provides a quadri-dimensional insight into flow dynamics, which has improved the semi-quantitative assessment of the severity in mitral regurgitation by taking into account the duration of the regurgitant jet within systole. It is also crucial for the study of multiple jets often seen in combined mitral disease and related to various diseased components of the mitral apparatus. Peculiar features of sites, directions and timings of jets enable the recognition of their mechanisms and draw the attention to a possible surface adherence effect, in the case of complicated trajectories impinging on the cardiac structures. Color Doppler imaging is also unique in singling out the precise site where the jets originate. This leads to developments of quantitation of stenosis based on planimetry of jet origin areas and to new quantitative methods relying on flow convergence information on one hand, and on the other hand, it helps approach to special lesional mechanisms such as, for instance bicuspid aortic valves, easily singled out by flow information from tricuspid aortic valves. This information will be crucial in the discussion of the type of repair procedure in the future.