Comparison of bolus and infusion of the ultrasound contrast agent Levovistfur colour Doppler ultrasound of renal arteries

Purpose: To investigate if the duration of Doppler enhancement of the ultra sound contrast agent Levovist can be prolonged by continuous infusion compa red to bolus injections in patients. Methods: 12 patients with suspected re nal artery stenosis were included. Each patient received 1 or 2 bolus injec tions of 4 g each and a "fast" infusion of 3 ml/min (average dose: 7 g) of Levovist. in 8 patients an additional "slow" infusion of 1 ml/min (average dose 4.2 g) was given. The duration of "strong" Doppler signal enhancement and the visualization of vessels were compared. Results: The duration of st rong enhancement was substantially prolonged by the slow infusion (bolus 6: 21 min, fast infusion: 8:57 min, slow infusion: 15:12 min, p < 0.001). The dose effectiveness (duration of strong enhancement per 1 g Levovist) was ma rkedly improved from 0:57 min (bolus) to 3:36 min (slow infusion). Visualis ation of the renal arteries was more complete with the slow infusion. Concl usion: Levovist infusions at 1 ml/min are superior to bolus injections in t he assessment of renal arteries. They prolong the enhancement, make more ef ficient use of a given dose of contrast material and thus allow additional clinically relevant information to be obtained at reduced cost.