Published online before print March 23, 2009, doi: 10.1161/CIRCULATIONAHA.108.826388
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(Circulation. 2009;119:1768-1775.)
© 2009 American Heart Association, Inc.
Imaging |
Molecular Magnetic Resonance Imaging of Myocardial Perfusion With EP-3600, a Collagen-Specific Contrast Agent
Initial Feasibility Study in a Swine Model
From the Department of Diagnostic Radiology, University Hospital, Technical University Aachen, Aachen, Germany (E.S., K.M.R., A.B., G.A.K., R.W.G.); Department of Radiology, University of Cologne, Cologne, Germany (E.S.); Department of Nuclear Medicine, Technical University Munich, Munich, Germany (R.M.B.); Philips Medical Systems, Best, the Netherlands (A.J.W.); EPIX Pharmaceuticals, Lexington, Mass (V.J., M.T.G.); and Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown (M.G.V., P.C.).
Reprint requests to Elmar Spuentrup, MD, Department of Radiology, University Hospital, University of Cologne, Kerpener Strasse 62, 50924 Cologne, Germany. E-mail spuenti{at}rad.rwth-aachen.de
Received December 4, 2007; accepted January 30, 2009.
Background— Cardiac magnetic resonance (MR) perfusion imaging during the first pass after intravenous administration of extracellular contrast agents is hampered by the spatial and temporal resolution achievable and by the artifacts seen in ultrafast MR imaging. Furthermore, time-consuming quantitative data analysis is often added. The use of molecular MR imaging with a target-specific contrast agent with perfusion-dependent binding to myocardium may enable prolonged visualization of perfusion defects and thus may help to overcome limitations of currently used first-pass extracellular MR imaging. EP-3600 is a new gadolinium-containing molecular contrast agent that binds reversibly to myocardial collagen.
Methods and Results— A significant but nonocclusive coronary artery stenosis was modeled in 7 domestic swine with an undersized MR-compatible balloon positioned in the left anterior descending artery as verified by x-ray angiography. Two animals died before contrast injection as a result of arrhythmias. In 5 swine, high-spatial-resolution gradient echo imaging (
1x1 mm2 in-plane resolution) was performed before and 5, 20, 40, and 60 minutes after intravenous administration of 12.3 µmol/kg EP-3600. Contrast was administered during stress induced by an infusion of 250 µmol · kg–1 · min–1 adenosine. Yb-DTPA was administered simultaneously for comparison of myocardium-to-plasma ratios. Images were assessed subjectively by 2 investigators, and signal-to-noise and contrast-to-noise ratios over time were calculated. Normal myocardium showed a significant signal-to-noise ratio increase during the entire examination time. In all animals (n=5), the perfusion defect in the left anterior descending artery territory could be visualized with a high contrast-to-noise ratio for at least 20 minutes after contrast injection. A significantly higher myocardium-to-plasma ratio was found for EP-3600 compared with the control agent Yb-DTPA (0.85±0.26 versus 0.22±0.08, respectively; P<0.01).
Conclusion— EP-3600 is a new molecular MR imaging contrast agent that binds to the myocardium and enables prolonged, high-contrast, high-spatial-resolution visualization of myocardial perfusion defects.
CLINICAL PERSPECTIVE
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Clinical Summaries
Circulation 2009 119: 1691-1693.[Extract] [Full Text]