Magnetic resonance imaging of pulmonary ventilation. Initial experiences with a gadolinium-DTPA-based aerosol.
OBJECTIVE
The authors investigate whether a modified gadolinium (Gd)-DTPA formulation can be aerosolized and used as a contrast agent for magnetic resonance (MR) ventilation imaging of the lungs.


METHODS
Gadolinium-DTPA (gadopentetate dimeglumine, Schering AG, Berlin, Germany, 100 mmol Gd/L) was modified by addition of mannitol (Sigma, Deisenhofen, Germany, 10 mg/mL) and the surface active detergent Lutrol F68 (BASF, Mannheim, Germany, 2 mg/mL). The imaging was performed in an anesthetized rat model after inhalation of the contrast agent aerosol (PulmoSonic, De Vilbiss, 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.


RESULTS
The modified Gd-DTPA aerosol elicited high and relatively homogeneous enhancement of the lung directly after nebulization. The enhancement was more pronounced than that obtained with a Gd-DTPA formulation without additives.


CONCLUSIONS
Gadolinium-DTPA-based aerosol appears to be a suitable contrast agent for MR ventilation imaging in an experimental animal model. Modification by mannitol (to increase proton density through a slight additional osmotic effect) and a detergent (to reduce droplet size by decreasing surface tension) is suitable and effective in increasing signal intensity compared with Gd-DTPA without modification.
Misselwitz
B
B
Research Laboratories of Schering AG, Berlin, Germany. Bernd.Misselwitz@Schering.DE
Mühler
A
A
Heinzelmann
I
I
Böck
J C
JC
Weinmann
H J
HJ
D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage* / Q000737:chemistry; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage* / Q000737:chemistry; D007089:Image Enhancement / Q000379:methods; D008168:Lung / Q000033:anatomy & histology* / Q000502:physiology; D008279:Magnetic Resonance Imaging; D009994:Osmolar Concentration; D012123:Pulmonary Ventilation / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013500:Surface Tension; D014783:Viscosity
D000336:Aerosols; D003287:Contrast Media; D019786:Gadolinium DTPA