Contrast techniques have been used to improve detection of peak velocities by Doppler spectral analysis. To define the effect of contrast enhancement on the tricuspid regurgitation (TR) jet area and length, 29 patients were studied (25 transthoracic, 4 transesophageal) with 2-dimensional color flow imaging. Three- to 5-ml of agitated saline was injected and images were obtained from 4-chamber views at 12- or 16-cm depth setting. Color gain was optimized to display TR jet at baseline and then reduced to minimal settings before injection. Measurements of TR jet area and length were made in 3 to 5 consecutive cycles. A ratio of TR jet area to 2-dimensional area was derived. TR jet area at baseline was 4.7 +/- 3.6 cm2 and increased significantly (p less than 0.0001) in 26 patients to 8.1 +/- 6.3 cm2 after contrast enhancement. Jet length at baseline was 3.4 +/- 1.7 cm and increased significantly (p less than 0.0001) in 20 patients to 4.1 +/- 1.8 cm after contrast enhancement. The ratio of TR jet area to right atrial area also increased significantly (p less than 0.0001) to greater than 0.20 in 18 of 28 patients after enhancement. Increases in jet area and length were not associated with changes in TR jet or diastolic inflow velocities measured by continuous wave Doppler at baseline and after contrast. Thus, contrast enhancement increases the amplitude of Doppler signals responsible for transvalvular and regurgitant flow. By reducing the effect of attenuation and improving signal-to-noise ratio, it improves delineation of the TR jet using color flow imaging.