BACKGROUND: Annexin V is a human phospholipid binding protein that binds to activated platelets in vitro. We sought to determine the potential of this agent for imaging intracardiac thrombi in swine. METHODS AND RESULTS: Left atrial thrombi were formed by crush injury. In initial nonimaging experiments using intravenous 125I-labeled human annexin V, the mean thrombus/whole blood ratio was 13.4 +/- 4.8 for the entire thrombus using well counting of resected specimens (n = 8). Using intravenously injected 99mTc-labeled human annexin V, the left atrial thrombus/blood ratio by well counting was similar (14.2 +/- 10.6 for the entire thrombus and 26.2 +/- 14.9 for the peak section) (n = 12). The ratio for a control protein, 125I-ovalbumin, was only 1.0 +/- 0.2. 99mTc tomographic imaging was positive (n = 10) or equivocal (n = 2) in all experiments with but negative in 10 controls without left atrial thrombi. By region-of-interest analysis of the tomographic images, the mean left atrial appendage/blood ratio at 2 hours in animals with a thrombus was 3.90 +/- 1.12 compared with 0.84 +/- 0.10 in closed chest controls and 1.01 +/- 0.23 in open chest controls (P < .001). CONCLUSIONS: We conclude that 99mTc-labeled human annexin V detects acute left atrial thrombi in vivo in swine. The combination of a new thrombus detection agent, annexin V, with a 99mTc label may allow in vivo imaging of thrombi in humans.
BACKGROUND:Annexin V is a human phospholipid binding protein that binds to activated platelets in vitro. We sought to determine the potential of this agent for imaging intracardiac thrombi in swine. METHODS AND RESULTS:Left atrial thrombi were formed by crush injury. In initial nonimaging experiments using intravenous 125I-labeled humanannexin V, the mean thrombus/whole blood ratio was 13.4 +/- 4.8 for the entire thrombus using well counting of resected specimens (n = 8). Using intravenously injected 99mTc-labeled humanannexin V, the left atrial thrombus/blood ratio by well counting was similar (14.2 +/- 10.6 for the entire thrombus and 26.2 +/- 14.9 for the peak section) (n = 12). The ratio for a control protein, 125I-ovalbumin, was only 1.0 +/- 0.2. 99mTc tomographic imaging was positive (n = 10) or equivocal (n = 2) in all experiments with but negative in 10 controls without left atrial thrombi. By region-of-interest analysis of the tomographic images, the mean left atrial appendage/blood ratio at 2 hours in animals with a thrombus was 3.90 +/- 1.12 compared with 0.84 +/- 0.10 in closed chest controls and 1.01 +/- 0.23 in open chest controls (P < .001). CONCLUSIONS: We conclude that 99mTc-labeled humanannexin V detects acute left atrial thrombi in vivo in swine. The combination of a new thrombus detection agent, annexin V, with a 99mTc label may allow in vivo imaging of thrombi in humans.
Authors: Christophe M M Lahorte; Jean-Luc Vanderheyden; Neil Steinmetz; Christophe Van de Wiele; Rudi A Dierckx; Guido Slegers Journal: Eur J Nucl Med Mol Imaging Date: 2004-05-12 Impact factor: 9.236
Authors: Jian Gong; Richard Archer; Michael Brown; Seth Fisher; Connie Chang; Matthew Peacock; Christopher Hughes; Bruce Freimark Journal: Mol Imaging Date: 2013-06 Impact factor: 4.488
Authors: F G Blankenberg; P D Katsikis; J F Tait; R E Davis; L Naumovski; K Ohtsuki; S Kopiwoda; M J Abrams; M Darkes; R C Robbins; H T Maecker; H W Strauss Journal: Proc Natl Acad Sci U S A Date: 1998-05-26 Impact factor: 11.205