Magnetic resonance imaging detection of an experimental pulmonary perfusion deficit using a macromolecular contrast agent. Polylysine-gadolinium-DTPA40.
OBJECTIVE
This study was designed to evaluate the potential of a blood-pool magnetic resonance (MR) contrast agent, polylysine-gadolinium-DTPA40 (polylysine-Gd-DTPA40) for detecting pulmonary perfusion defects.


METHODS
Pulmonary emboli were induced in 10 rats by venous injection of 0.2 mL of air. Axial spin-echo images were acquired (TR = 800 mseconds; TE = 6 mseconds) before and after air injection and serially after the administration of polylysine-Gd-DTPA40. The embolism model was confirmed by scintigraphy using 99mTc-macroaggregated albumin.


RESULTS
Signal intensity differences between normal and embolized lungs before and after the air injection were less than 25%. After polylysine-Gd-DTPA40 administration, signal intensity of the perfused lung increased more than 200%, whereas the embolized lung increased by only 25%. Signal intensities of the perfused lung remained stable for 1 hour, whereas signal intensities of the embolized lung gradually increased for 20 minutes as the air embolus dissolved.


CONCLUSIONS
Magnetic resonance imaging (MRI) enhanced with a macromolecular blood-pool contrast agent can be used to detect acute pulmonary embolism in a confirmed animal model.
Berthezène
Y
Y
Contrast Media Laboratory, Department of Radiology, University of California, San Francisco 94143-0628.
Vexler
V
V
Price
D C
DC
Wisner-Dupon
J
J
Moseley
M E
ME
Aicher
K P
KP
Brasch
R C
RC
D000818:Animals; D003287:Contrast Media; D004353:Drug Evaluation, Preclinical; D004618:Embolism, Air / Q000175:diagnosis*; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D008168:Lung / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D008970:Molecular Weight; D009942:Organometallic Compounds; D004369:Pentetic Acid; D011107:Polylysine / Q000031:analogs & derivatives; D011655:Pulmonary Embolism / Q000175:diagnosis*; D051381:Rats; D011919:Rats, Inbred Strains
D003287:Contrast Media; D009942:Organometallic Compounds; C068674:polylysine-(Gd-DTPA); D011107:Polylysine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA