Prolongation of TCD-enhanced Doppler signal by continuous infusion of levovist

Grey scale enhancement of rabbit liver and kidney by intravenous injection of a new lipid-coated ultrasound contrast agent

AIM: To assess the grey scale enhancement of a new lipid-coated ultrasound contrast agent in solid abdominal organs as liver and kidney.

METHODS: Size distribution and concentration of the lipid-coated contrast microbubbles were analyzed by a Coulter counter. Two-dimensional (2D) second harmonic imaging of the hepatic parenchyma, the inferior vena cava and the right kidney of the rabbits were acquired before and after contrast agent injection. Images were further quantified by histogram in Adobe Photoshop 6.0. Time-intensity curves of hepatic parenchyma, inferior vena cava and renal cortex were generated from the original grey scale.

RESULTS: The 2D images of hepatic parenchyma and cortex of the kidney were greatly enhanced after injection and the peak time could last more than 50 min.

CONCLUSION: This new lipid ultrasound contrast agent could significantly enhance the grey scale imaging of the hepatic parenchyma and the renal cortex for more than 50 min.

Contrast-enhanced duplex scanning of crural arteries by means of continuous infusion of Levovist

OBJECTIVES

To estimate the dosage needed for continuous infusion and to investigate whether continuous infusion of the ultrasound contrast-enhancing agent Levovist (SH U 508A) can improve duplex scanning of crural arteries in patients with peripheral arterial obstructive disease (PAOD) eligible for distal bypass graft surgery.

DESIGN, PATIENTS, AND METHODS

The study design consisted of two parts. Part 1 investigated the color and spectral Doppler scan enhancement of three different Levovist dosages (200, 300, and 400 mg/mL) in one arterial segment of a patent lumen of a crural artery in seven patients with PAOD. Part 2 investigated the value of the optimum Levovist dosage in the assessment of 10 crural arteries in 10 consecutive patients with PAOD. Angiography was the reference standard.

RESULTS

Part 1: Levovist significantly enhanced color and spectral Doppler scan as compared with baseline ultrasound scan, but no differences were found between the Levovist dosages. Thus, the lowest Levovist dosage sufficed for application in part 2, because of its infusion volume and prolonged enhancement time. Part 2: The agreement between contrast-enhanced duplex scanning and angiography was moderate (kappa = 0.50; 95% confidence interval [CI], 0.03-0.97). Five (50%) of 10 crural arteries that could not adequately be visualized with routine duplex scanning could be visualized with contrast-enhanced duplex scanning.

CONCLUSION

Contrast-enhanced duplex scanning by means of continuous infusion of Levovist in patients with PAOD improves the ultrasound scan investigation of crural arteries in case routine duplex scanning is inconclusive and might reduce the need for angiography.