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Dynamics of novel CT contrast agents for preclinical imaging Host Publication: European Congres of Radiology (ECR 2012), Vienna, March 2012 Authors: I. Willekens, T. Lahoutte, N. Buls, L. Goethals, G. Van Gompel, F. Verhelle, R. Deklerck, A. Bossuyt and J. De Mey Publication Date: Mar. 2012
Abstract: Purpose
To evaluate five commercially available CT contrast agents (Exitron P, Exitron U, Exitron V, Exitron nano 6000, and Exitron nano 12000) regarding to their signal enhancement in different tissues.
Methods and Materials
We injected all contrast agents, Exitron P, Exitron U, Exitron V, Exitron nano 6000, and Exitron nano 12000 (Miltenyl Biotec GmbH, Auburn, USA), intravenously in C57bl/6 mice (n=37). Initially at a dose of 0.1 ml/25g (n=22), as indicated on the manual. In case of decease, 0.05/25g was injected (n=15).
Animals were anesthetized with Isoflurane. Anesthesia was induced with 5% Isoflurane and maintained at 2% during the scan with spontaneous breathing via a nose cone.
Imaging was performed using micro-CT system (SkyScan 1178 micro-CT SkyScan, Kontich, Belgium) at a resolution of 83 µm before contrast injection, immediately after contrast injection and at 15 min, 30 min, 45 min, 1h, 2h, 3h, 4h, 24h and 48h after contrast (scan duration: 121 sec).
Images were analysed using Amide. Regions of interest were drawn in spleen, liver, and left ventricle. The contrast enhancement was measured and expressed in function of time.
Results
Our results show that the recommended dose of 0.1 ml/25g was lethal with ExiTron P, Exitron nano 6000, and Exitron nano 12000: they died immediately after contrast injection. Even doses of 0.05 ml/25g of Exitron P was lethal. The Exitron U and Exitron V contrast enhancement of the spleen reaches a maximum just after contrast injection, while the maximum liver enhancement occurs at 1h after injection of Exitron V and at 3h after injection of Exitron U. Maximum contrast enhancement of the spleen after Exitron nano 6000 and Exitron nano 12000 occurs after 48h, while the maximum liver enhancement is after 4h for Exitron nano 6000 and after 24h for Exitron nano 12000. Enhancement in the cardiac cavity is the highest after Exitron nano 12000.
Conclusion
Soft tissue enhancement is feasible in small animals, yielding longlasting contrast. However, injection volume seems to be a crucial point.
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