MR diagnosis of a pulmonary embolism: comparison of P792 and Gd-DOTA for first-pass perfusion MRI and contrast-enhanced 3D MRA in a rabbit model.
OBJECTIVE
To compare P792 (gadomelitol, a rapid clearance blood pool MR contrast agent) with gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA), a standard extracellular agent, for their suitability to diagnose a pulmonary embolism (PE) during a first-pass perfusion MRI and 3D contrast-enhanced (CE) MR angiography (MRA).


METHODS
A perfusion MRI or CE-MRA was performed in a rabbit PE model following the intravenous injection of a single dose of contrast agent. The time course of the pulmonary vascular and parenchymal enhancement was assessed by measuring the signal in the aorta, pulmonary artery, and lung parenchyma as a function of time to determine whether there is a significant difference between the techniques. CE-MRA studies were evaluated by their ability to depict the pulmonary vasculature and following defects between 3 seconds and 15 minutes after a triple dose intravenous injection of the contrast agents.


RESULTS
The P792 and Gd-DOTA were equivalent in their ability to demonstrate PE as perfusion defects on first pass imaging. The signal from P792 was significantly higher in vasculature than that from Gd-DOTA between the first and the tenth minutes after injection. The results suggest that a CE-MRA PE could be reliably diagnosed up to 15 minutes after injection.


CONCLUSIONS
P792 is superior to Gd-DOTA for the MR diagnosis of PE.
Keilholz
Shella D
SD
Department of Biomedical Engineering, Emory University, Atlanta, GA, USA.
Bozlar
Ugur
U
Fujiwara
Naomi
N
Mata
Jaime F
JF
Berr
Stuart S
SS
Corot
Claire
C
Hagspiel
Klaus D
KD
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D021621:Imaging, Three-Dimensional; D007275:Injections, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000008:administration & dosage; D011655:Pulmonary Embolism / Q000175:diagnosis*; D011817:Rabbits
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; C435266:contrast agent P792