MAGNETIC-RESONANCE-IMAGING OF PULMONARY VENTILATION - INITIAL EXPERIENCES WITH A GADOLINIUM-DTPA-BASED AEROSOL

RATIONALE AND OBJECTIVES. The authors investigate whether a modified g adolinium (Gd)-DTPA formulation can be aerosolized and used as a contr ast agent for magnetic resonance (MR) ventilation imaging of the lungs , METHODS. Gadolinium-DTPA (gadopentetate dimeglumine, Schering AG, Be rlin, Germany, 100 mmol Gd/L) was modified by addition of mannitol (Si gma, Deisenhofen, Germany, 10 mg/mL) and the surface active detergent Lutrol F68 (BASF, Mannheim, Germany, 2 mg/mL), The imaging was perform ed in an anesthetized rat model after inhalation of the contrast agent aerosol (PulmoSonic, DeVilbiss, Germany, 10-minute nebulization). T1- weighted spin echo images (repetitive time [TR]/echo time [TE] = 40/3 mseconds) were acquired at 2 T (SIS 85; Sisco, Fremont, CA) before and as long as 120 minutes after administration of the contrast agent. RE SULTS. The modified Gd-DTPA aerosol elicited high and relatively homog eneous enhancement of the lung directly after nebulization. The enhanc ement was more pronounced than that obtained with a Gd-DTPA formulatio n without additives, CONCLUSIONS. Gadolinium-DTPA-based aerosol appear s to be a suitable contrast agent for MR ventilation imaging in an exp erimental animal model, Modification by mannitol (to increase proton d ensity through a slight additional osmotic effect) and a detergent (to reduce droplet size by decreasing surface tension) is suitable and ef fective in increasing signal intensity compared with Gd-DTPA without m odification.