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Imaging of pulmonary embolism and t-PA therapy effects using MDCT and liposomal iohexol blood pool agent – preliminary results in a rabbit model
Journal article   Open access   Peer reviewed

Imaging of pulmonary embolism and t-PA therapy effects using MDCT and liposomal iohexol blood pool agent – preliminary results in a rabbit model

Stephen J Burke, Ananth Annapragada, Eric A Hoffman, Emmanuel Chen, Ketan B Ghaghada, Jered Sieren and Edwin JR van Beek
Academic radiology, Vol.14(3), pp.355-362
03/2007
DOI: 10.1016/j.acra.2006.12.014
PMCID: PMC2213908
PMID: 17307669
url
https://www.research.ed.ac.uk/en/publications/50b6d344-3f19-4bb3-91d1-22fc15fd2a9cView
Open Access

Abstract

Rationale and objectives: Polyethylene glycol-coated liposomal blood pool contrast agents maintain contrast enhancement over several hours. This study aimed to evaluate (long-term) imaging of pulmonary arteries, comparing conventional iodinated contrast with a liposomal blood pool contrast agent. Also, visualization of the (real-time) therapeutic effects of tissue plasminogen activator (t-PA) on pulmonary embolism (PE) was attempted. Materials and methods: Six rabbits (weight approximately 4 kg) had autologous blood clots injected through the superior vena cava. Imaging was performed using conventional contrast (iohexol, 350 mg I/ml; GE HealthCare, Princeton, NJ) at a dose of 1400 mg I per animal, and after wash-out, animals were imaged using an iodinated liposomal blood pool agent (88 mg I/mL, dose 900 mg I/animal). Subsequently, five animals were injected with 2 mg of t-PA and imaging continued for up to 4(1/2) hours. Results: Both contrast agents identified PE in the pulmonary trunk and main pulmonary arteries in all rabbits. Liposomal blood pool agent yielded uniform enhancement, which remained relatively constant throughout the experiments. Conventional agents exhibited nonuniform opacification and rapid clearance postinjection. Three of six rabbits had mistimed bolus injections, requiring repeat injections. Following t-PA, pulmonary embolus volume (central to segmental) decreased in four of five treated rabbits (range 10-57%, mean 42%). One animal showed no response to t-PA. Conclusions: Liposomal blood pool agents effectively identified acute PE without need for reinjection. PE resolution following t-PA was quantifiable over several hours. Blood pool agents offer the potential for repeated imaging procedures without need for repeated (nephrotoxic) contrast injections.
thrombolysis iodinated contrast agents pulmonary embolism blood pool liposomes

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