Abstract 13239: Molecular Imaging of Arterial and Deep Vein Thrombosis: Toward a Single-modality Approach for Thrombus Detection and Fibrin Content Estimation
Thrombosis is a leading cause of morbidity and mortality worldwide, and thrombus imaging is critical for diagnosis and intervention. Current diagnostic strategies rely on different imaging modalities that are specific for distinct vascular territories, but a single-modality approach is still missing. Moreover, imaging techniques to assess thrombus composition are underdeveloped, although therapeutic strategies may benefit from such technology.
Here, we tested whether non-invasive imaging using a fibrin-specific PET probe is suitable to detect the clot location and to assess fibrin content of both arterial and venous thrombi.
Ferric chloride (25%) was applied on both carotid artery and femoral vein of 21 Sprague-Dawley rats to induce thrombosis. The fibrin-binding probe FBP8 was injected 1, 3 or 7 days after thrombus induction, and PET/CT imaging was performed starting 1 hour after probe injection. Ex vivo biodistribution, autoradiography and histology were performed on thrombosed and contralateral vessels to validate the imaging results.
After FBP8 injection, arterial (A) and venous (B) thrombi were clearly localized (arrow) on fused PET/CT images. Thrombosis was confirmed by H&E staining (C). PET imaging showed that probe uptake was greater in fresh clots than in older ones for both arterial and venous thrombosis (D, P<0.01, ANOVA + Tukey post-hoc test, n=7/group). Ex vivo biodistribution (E, % injected dose per gram of tissue) and autoradiography (F, ratios between radioactivity in ipsilateral vs. contralateral vessels) showed results comparable to PET quantification. Martius scarlet blue staining showed a time-dependent reduction of fibrin content in the thrombus (G, purple region), supporting the imaging findings.
In conclusion, we showed that FBP8 is suitable for detection of both arterial and venous thrombosis at different stages of thrombus evolution, and that molecular imaging of fibrin can provide, non-invasively, insight on clot composition.
Author Disclosures: F. Blasi: None. B.L. Oliveira: None. T. Rietz: None. N. Rotile: None. P. Caravan: Ownership Interest; Significant; Peter Caravan has equity in Factor 1A, LLC, the company holding the patent rights to the peptide used in this work.
- © 2014 by American Heart Association, Inc.