Improved sensitivity of color Doppler by SH U 454.

SH U 454, a suspension of galactose microparticles, provides microbubbles (97% less than 7 microns) in variable, reproducible concentrations. Its influence on color Doppler imaging was evaluated in a flow model study and in a clinical study. In the flow model, increasing attenuation (up to 11.4 dB/MHz) impaired the signal to noise ratio and decreased the sensitivity for detecting flow velocities. Thus, flow signals were obtained with flow velocities greater than 3 cm/s (0.1 dB/MHz), greater than 9 cm/s (5.7 dB/MHz) and greater than 17 cm/s (11.4 dB/MHz). After injection of SH U 454 (200 mg/ml), velocities down to 3 cm/s were detected even with high attenuation (11.4 dB/MHz). Color Doppler imaging was performed before and after intravenous injection of 2 ml, 3 ml and 4 ml of SH U 454 (200 mg/ml) in 22 adult patients, and the maximal color-coded areas of diastolic blood flow were determined in the right atrium and ventricle. In 19 of 22 patients, the displayed color-coded areas increased after injection of SH U 454. The diastolic blood flow was imaged on 14 +/- 8% (mean +/- 1 standard deviation) of the cross-sectional area of the right ventricle (4-chamber view) without SH U 454, compared with 39 +/- 15% with 3 ml of SH U 454 (p less than 0.001). For the right atrium, the area displayed by color Doppler increased from 9 +/- 13 to 62 +/- 25% (p less than 0.001). The variability of the measurements from patient to patient after injection of SH U 454 was 5.9 +/- 4% as compared with 10.7 +/- 6.9% without SH U 454 (p less than 0.05). These findings indicate that the intravenous injection of SH U 454 increases the sensitivity of color Doppler imaging for detection of blood flow by improving the signal to noise ratio.