Enhancement of Doppler signals in aortic and mitral valve diseases

: Ultrasound contrast media increase backscatter from blood, thus improving the signal-to-noise ratio. Potential clinical applications of intravenous ultrasound contrast are reviewed. Contrast enhancement of continuous wave Doppler is indicated when the native recordings are noisy and no complete envelope of the Doppler spectrum is obtained. In aortic stenosis several investigations showed good agreement between the gradient calculated from Doppler measurements and the results of cardiac catheterization. In mitral insufficiency maximum area of the regurgitant jet is a widely used parameter for estimation of the severity of the regurgitation. However, assessment of the maximum jet area may not be possible because of poor acoustic windows. Contrast enhancement provides complete display of the regurgitant jet in most of the patients. The diagnostic confidence of the Doppler investigation is further improved by the recording of the pulmonary venous flow, which can be recorded in most of the patients following contrast injection. Therefore contrast enhanced transthoracic Doppler is an alternative to transesophageal Doppler investigation in patients with poor transthoracic windows.