The analysis of the pulmonary venous flow Doppler pattern can assist in the determination of the severity of mitral regurgitation and, in conjunction with transmitral flow pattern, the assessment of left ventricular diastolic dysfunction. In approximately one third of the cases, however, transthoracic ultrasonography is not able to record an adequately analyzable pulmonary venous flow pattern. The aim of the study was to examine and compare the effect of the echo-enhancing agent Levovist on the pulsed-wave Doppler flow quality of the transthoracic (TTE) and transesophageal (TEE) recorded pulmonary venous flow. In 26 consecutive patients a qualitative (score system) and quantitative analysis of pulmonary venous flow pattern was obtained before and after peripheral venous injection of Levovist at concentrations of 200 mg/ml (low dose) and 400 mg/ml (high dose). The amount of measurable studies for the antegrade pulmonary venous flow increased after the injection of Levovist from 85% to 96% for TTE and from 96% to 100% for TEE. The retrograde flow as seen by TTE was adequately analyzable in only 46% before and in 73% after the injection of Levovist (p < 0.02). Before any contrast enhancement the retrograde pulmonary venous flow recorded by TEE could be analyzed in 77% of the patients, with the percentage increasing to 88% and 92% after the administration of a low and high dose of Levovist, respectively (p < 0.05). In particular, the quality score of the retrograde flow was significantly altered by the administration of Levovist (increase from 1.8 +/- 1.0 to 2.6 +/- 1.1 [low dose Levovist], p < 0.05 and to 2.7 +/- 1.3 [high dose Levovist], p < 0.05). The pulsed-wave Doppler interrogation by TTE without Levovist underestimated the velocities of the antegrade and retrograde pulmonary venous flow. After Levovist was administered, the recorded values were comparable to those obtained by TEE. An analogous pattern is encountered when quantifying the duration of the retrograde flow component. Thus the peripheral venous injection of Levovist leads to an improved quality of the pulmonary venous flow Doppler signal recorded by TTE. On qualitative and quantitative evaluation the values recorded by TTE after administration of Levovist are comparable to those of the TEE technique without an echo-enhancing agent.