Molecular magnetic resonance imaging of atrial clots in a swine model.
BACKGROUND
The detection and differentiation of intracardiac masses is still challenging and may include neoplasms and thrombi. The aim of this study was the investigation of a targeted, fibrin-specific contrast agent (EP-2104R) for molecular targeted magnetic resonance imaging (MRI) of left atrial clots.


RESULTS
Chronic human thrombi were surgically implanted in the left atrial appendage of 5 swine. Molecular MRI was performed with a navigator-gated, free-breathing, cardiac-triggered 3D inversion-recovery, black-blood, gradient-echo sequence before and after systemic administration of 4 micromol/kg EP-2104R. MR images were analyzed by 2 investigators, and the contrast-to-noise ratio was calculated. Location of clots was confirmed by autopsy, and the gadolinium concentration in the clots was assessed. Before contrast agent administration, thrombi were not visible on black-blood MR images. After contrast administration, all atrial clots (n=5) were selectively visualized as white spots with a high contrast-to-noise ratio (clot/blood, 29.7+/-8.0). The gadolinium concentration in the clots averaged 74+/-45 micromol/L.


CONCLUSIONS
The fibrin-specific MR contrast agent EP-2104R allows for selective and high-contrast visualization of left atrial clots by means of molecular targeted MRI.
Spuentrup
Elmar
E
Department of Diagnostic Radiology, Aachen Technical University, Aachen, Germany. spuenti@rad.rwth-aachen.de
Fausten
Bernd
B
Kinzel
Sylvia
S
Wiethoff
Andrea J
AJ
Botnar
Rene M
RM
Graham
Philip B
PB
Haller
Stephan
S
Katoh
Marcus
M
Parsons
Edward C
EC
Manning
Warren J
WJ
Busch
Thomas
T
Günther
Rolf W
RW
Buecker
Arno
A
D000818:Animals; D006325:Heart Atria; D006331:Heart Diseases / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D013552:Swine; D013927:Thrombosis / Q000175:diagnosis*