词条 | Blood pool agent |
释义 |
Blood pool agents (BPAs) are a class of magnetic resonance angiography contrast agents.[1][2] Blood pool agents (also known as intravascular contrast agents) are differentiated from other contrast agents due to their high molecular weight and higher relaxivities.[3] Their large size prevents diffusion through the vascular epithelium and leakage into the interstitial space, and because of this they stay in the vascular system for a longer time period. Most contrast agents, leave the vascular system within a few minutes, however blood pool agents remain in the circulation for up to an hour, extending the window available for imaging. Longer image acquisition times allow better signal-to-noise ratio and improved image resolution. Roles of blood pool agentsDue to their extended time in the circulatory system, blood pool agents can be used for delayed steady-state imaging, and additionally these results can be combined with first pass arterial imaging.[2][3] Their extended circulation time means that they are able to be used for both arterial and venous mapping. Additional uses include: detection of gastrointestinal bleeding; visualization of the vasculature associated with certain tumors; measuring tissue blood volume and perfusion; and detection of endovascular leaks (such as following stent-graft repair of an aortic aneurysm). Classes of blood pool agentsAlbumin-binding gadolinium complexesThis class of BPAs is based on the noncovalent binding of low molecular weight Gd3+-based complexes to human serum albumin. The first commercial agent to be approved in this class is gadofosveset trisodium[4] (also known as Vasovist®[5] or Ablavar®,[6] and previously known as MS-325[7]). Many clinical and case studies documenting the use of this BPA have been published,[8][9][10][11][12][13][14] and its efficacy in enhancing blood vessels visibility has been demonstrated.[15] The manufacturer (Lantheus Medical) discontinued production in 2017 though, due to poor sales.[16] Gadocoletic acid[17] (Bracco SpA), also known as B-22956 and B22956/1, is a Gd-DTPA derivative that is currently in development, but has not yet been approved for clinical use. Gadobenic acid (MultiHance®[18]) is sometimes categorized as a BPA; however, as it only binds weakly to albumin and because hepatobiliary uptake of this compound occurs, this contrast agent should not be classified as a BPA. Polymeric gadolinium complexesPolymeric Gd3+ chelates are large in size, which prevents leakage into the interstitial space, and provides long imaging windows. Several polymeric gadolinium-based BPAs are currently in development but have not yet been approved for clinical use: Gadomelitol[19] (Guerbet, France), also known as Vistarem® and P792 Gadomer-17[20] (Schering AG, Berlin, Germany) also known as Gd-DTPA-17, SH L 643 A. References1. ^{{cite web|url=http://www.magnetic-resonance.org/ch/13-01.html|title=MR Contrast Agents|year=2014}} 2. ^1 Blood Pool Agents 3. ^1 Geraldes CF, Laurent S, Classification and basic properties of contrast agents for magnetic resonance imaging, Contrast Media Mol Imaging, 2009;4:1-23. 4. ^Ablavar (gadofosveset trisodium) injection 5. ^VASOVIST (gadofosveset trisodium) 6. ^Ablavar® 7. ^MS-325. Magnetic Resonance - Technology Information Portal 8. ^Wolf F, Plank C, Beitzke D, et al., Prospective evaluation of high-resolution MRI using gadofosveset for stent-graft planning: comparison with CT angiography in 30 patients, AJR Am J Roentgenol, 2011;197:1251-7 9. ^Partovi S, Aschwanden M, Staub D, et al., Gadofosveset enhanced MR phlebography for detecting pelvic and deep vein leg thrombosis, Vasa, 2011;40:315-9 10. ^Haneder S, Attenberger UI, Biffar A, et al., Gadofosveset: parameter optimization for steady-state imaging of the thoracic and abdominal vasculature, Invest Radiol, 2011;46:678-85 11. ^Pfeil A, Betge S, Poehlmann G, et al., Magnetic resonance VIBE venography using the blood pool contrast agent gadofosveset trisodium-An interrater reliability study, Eur J Radiol, 2011;81:547-52 12. ^Pedersen SF, Thrysoe SA, Paaske WP, et al., CMR assessment of endothelial damage and angiogenesis in porcine coronary arteries using gadofosveset, J Cardiovasc Magn Reson, 2011;13:10 13. ^Yamashita T, Takahara T, Kwee TC, et al., Diffusion magnetic resonance imaging with gadofosveset trisodium as a negative contrast agent for lymph node metastases assessment, Jpn J Radiol, 2011;29:25-32 14. ^Lambregts DM, Beets GL, Maas M, et al., Accuracy of gadofosveset-enhanced MRI for nodal staging and restaging in rectal cancer, Ann Surg, 2011;253:539-45 15. ^McGregor R, Vymazal J, Martinez-Lopez M, et al., A multi-center, comparative, phase 3 study to determine the efficacy of gadofosveset-enhanced magnetic resonance angiography for evaluation of renal artery disease, Eur J Radiol, 2008;65:316-25 16. ^{{cite web |last1=Bell |first1=Daniel |last2=Morgan |first2=Matt |title=Gadofosveset trisodium |url=https://radiopaedia.org/articles/gadofosveset-trisodium-1 |website=Radiopaedia |publisher=radiopaedia.org |accessdate=2018-08-28}} 17. ^Gadocoletic acid {{webarchive |url=https://web.archive.org/web/20120128084125/http://www.bloodpoolagents.us/categories/blood-pool-imaging/investigational-agents/gadocoletic-acid |date=January 28, 2012 }} 18. ^MultiHance® 19. ^Gadomelitol {{webarchive |url=https://web.archive.org/web/20120128084131/http://www.bloodpoolagents.us/categories/blood-pool-imaging/investigational-agents/gadomelitol |date=January 28, 2012 }} 20. ^Gadomer-17 {{webarchive |url=https://web.archive.org/web/20120128084136/http://www.bloodpoolagents.us/categories/blood-pool-imaging/investigational-agents/gadomer-17 |date=January 28, 2012 }} 1 : Contrast media |
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