Abdominal MR angiography performed using blood pool contrast agents: comparison of a new superparamagnetic iron oxide nanoparticle and a linear gadolinium polymer.
OBJECTIVE
We evaluated and compared two different experimental blood pool contrast agents for abdominal MR angiography in an animal model.


METHODS
In seven pigs, coronal T1-weighted three-dimensional fast field-echo images were obtained on a conventional 1.5-T MR imaging system before and after i.v. injection of the ultrasmall superparamagnetic iron oxide agent FeO-BPA. In another seven pigs, MR angiograms were acquired using the gadolinium polymer WIN 22181. Enhanced images were obtained 5-210 min after injection of FeO-BPA and 1-120 min after injection of WIN 22181.


RESULTS
Both blood pool agents yielded detailed angiograms of the abdominal vascular tree when imaging lasted 2 min. In-plane running vessels were imaged without saturation effects and with equivalent maximum signal-to-noise ratios. Half the maximum signal-to-noise ratio was reached 150 min after injection of FeO-BPA, whereas this interval was approximately 70 min for the gadolinium polymer. Because of these different imaging half-life periods, the effective diagnostic window provided by FeO-BPA was six to eight times longer than that of WIN 22181. In the liver, the vascular T1 shortening and the parenchymal T2* effect of FeO-BPA complemented each other, resulting in an optimal contrast-to-noise ratio significantly higher than that achieved with WIN 22181. This "double-contrast effect" in the liver was especially helpful when obtaining detailed MR portograms.


CONCLUSIONS
The blood pool agents FeO-BPA and WIN 22181 can be used to produce high-quality abdominal MR angiograms on standard MR imaging equipment. The contrast-to-noise ratio of hepatic vessels is best on iron oxide-enhanced images because of a T1-T2* synergistic effect in the liver. The longer diagnostic window provided by FeO-BPA coupled with the option of in-plane imaging suggests the usefulness of FeO-BPA in future MR imaging-guided vascular interventions.
Nolte-Ernsting
C
C
Department of Diagnostic Radiology, University of Technology, Aachen, Germany.
Adam
G
G
Bücker
A
A
Berges
S
S
Bjørnerud
A
A
Günther
R W
RW
D000005:Abdomen / Q000098:blood supply; D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D052203:Ferrosoferric Oxide; D005682:Gadolinium; D006207:Half-Life; D007501:Iron; D018810:Magnetic Resonance Angiography / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D010087:Oxides; D011108:Polymers; D013552:Swine
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D011108:Polymers; C108041:WIN 22181; C097921:ferumoxtran-10; D005682:Gadolinium; D007501:Iron; D052203:Ferrosoferric Oxide