Right-heart echocontrast in the anesthetized dog after i.v. administration of a new standardized sonographic contrast agent. 1st communication: dose-response relationship.

The newly developed standardized sonographic contrast agent SH U 454, which consists of pure galactose microparticles, was examined for opacification of the right heart by 2 D echocardiography in 10 anesthetized female beagle dogs (6.8-12.7 kg) following i.v. administration. The right ventricular contrast of SH U 454 was investigated in 4 concentrations: 100, 150, 200 and 300 mg microparticles/ml suspension. With a 5-min interval between injections each animal was given 3 injections of 2 ml of each formulation in random order using an injection speed of approximately 2 ml/s. The echocardiographic pictures were recorded on videotape and the contrast assessed blind, using a visual score system (ratings 0-5), by two investigators working independently and also by a videodensitometer which measured 3 additional parameters. The contrast obtainable with SH U 454 is dose-dependent. SH U 454 containing 300 mg microparticles/ml was in every case significantly superior (p less than 0.05) to the suspension containing 100 mg/ml. All the videodensitometer values revealed a significant difference (p less than 0.05) between the 200 and 100 mg/ml concentrations. Only the concentration containing 300 mg/ml yielded contrast adequate for diagnostic purposes in respect of every parameters after every injection and in every dog.