should be timed 1–2 minutes apart. Images can be stacked using stacking software to improve visualization when a bolus appears disrupted. If concern for trapping occurs, aspiration may be necessary.


CO2


angiography has limitations in defining the anatomy of large diameter vessels (aorta or inferior vena cava) and may overestimate the degree of stenosis.8


Because of the risk of cerebrovascular injury,7 intra-arterial CO2


is contraindicated above the diaphragm and in patients with known right to left shunt.9


Additionally, it should be


avoided with nitrous oxide anesthesia. Images should be obtained at higher speed (i.e., 5–6 frames/second) with a CO2


the contrast media shortage. In addition to minimizing contrast usage, IVUS also decreases radiation exposure and procedural times.10


Additional procedures for which IVUS can be used to either mitigate or eliminate the use of contrast include but are not limited to IVC filter placement, angioplasty, coronary interventions and complex peripheral vascular interventions. For portal interventions, numerous reports have cited ICE use to guide portal venous puncture for placement of transjugular intrahepatic portosystemic shunts (TIPS).


dosage 1.5–2 times that which may


have been used for iodinated contrast. Capnography should be used to monitor for malperfusion when administering CO2


as elimination is highly dependent on cardiac output.


IVUS and intracardiac echocardiography (ICE) IVUS has long held a role in vascular procedures for its ability to accurately assess vessel luminal size and evaluate pathology. Historically, this has most commonly been used in cases of arterial dissections and placement of intravascular stents. However, the applications of IVUS are broad and primed for increased usage considering


Gastrografin and cystografin for nonvascular procedures In addition to Gd, water-soluble iodinated contrast (diatrizoate meglumine, Gastrografin and Cystografin, Bracco Diagnostics, Monroe Township, N.J.) for gastrointestinal and genitourinary applications can be used for certain nonvascular interventions.


For example, for gastrointestinal access and exchange procedures (gastrostomy/ gastrojejunostomy), Gastrografin is a safe alternative given that it is water soluble. Similarly, for genitourinary access and exchange (nephrostomy/ nephroureterostomy), Cystografin is a viable alternative.


Listen to this article at bit.ly/ jvira-2 or to a discussion with the authors at bit.ly/KWire-032. For more context, read the press release at bit.ly/3xTDUp3.


Conclusion While the use of iodinated CM has long been the standard for interventional procedures, the global shortage requires the proceduralist to reevaluate this commodity. Gd, CO2


and IVUS can be


used to help mitigate or eliminate the need for iodinated CM in a significant portion of IR procedures that need to be performed on an semi-elective/urgent bases, thus leaving the limited supply to emergency cases.


For elective procedures, particularly those where permanent implants are placed, it may be prudent to defer until iodinated CM is available. Practice-level changes and procedural adjustments may benefit patients in the long term by making practitioners more savvy and nimble with alternative ways of anatomic visualization, thereby minimizing patient contrast and radiation dosage.


References


1. Media ACoDaC. Statement from the ACR Committee on Drugs and Contrast Media. acr. org/Advocacy-and-Economics/ACR-Position- Statements/Contrast-Media-Shortage. Published 2022. Updated May 6, 2022. Accessed 9 May 2022.


2. Ibrahim MA, Hazhirkarzar B, Dublin AB. Gadolinium Magnetic Resonance Imaging. [Updated 2021 Jul 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.


3. Meng B, Cong W, Xi Y, De Man B, Wang G. Energy Window Optimization for X-Ray K-Edge Tomographic Imaging. IEEE Trans Biomed Eng. 2016;63(8):1623–1630. doi:10.1109/ TBME.2015.2413816.


4. Sambol EB, Van der Meer JG, Graham A, Goldstein LJ, Karwowski JK, Dayal R, Derubertis B, Kent KC. The use of gadolinium for arterial interventions. Ann Vasc Surg. 2011 Apr;25(3):366–76.


5. Spinosa DJ, Kaufmann JA, Hartwell GD. Gadolinium chelates in angiography and interventional radiology: a useful alternative to iodinated contrast media for angiography. Radiology. 2002 May;223(2):319–25; discussion 326–7.


6. Tasaki Y, Sueyoshi E, Takamatsu H, et al. The outcomes of carbon dioxide digital subtraction angiography for percutaneous transluminal balloon angioplasty of access circuits and venous routes in hemodialysis patients. Medicine (Baltimore). 2020;99(36):e21890. doi:10.1097/ MD.0000000000021890.


7. Ehrman KO, Taber TE, Gaylord GM, Brown PB, Hage JP. Comparison of diagnostic accuracy with carbon dioxide versus iodinated contrast material in the imaging of hemodialysis access fistulas. J Vasc Interv Radiol. 1994 Sep-Oct;5(5):771–5.


8. Sharafuddin MJ, Marjan AE. Current status of carbon dioxide angiography. J Vasc Surg. 2017 Aug;66(2):618–637.


9. Spinosa DJ, Angle JF, Hartwell GD, Hagspiel KD, Leung DA, Matsumoto AH. Gadolinium- based contrast agents in angiography and interventional radiology. Radiol Clin North Am. 2002 Jul;40(4):693–710.


10. Marteslo JP, Makary MS, Khabiri H, Flanders V, Dowell JD. Intravascular Ultrasound for the Peripheral Vasculature-Current Applications and New Horizons. Ultrasound Med Biol. 2020 Feb;46(2):216–224. doi:10.1016/j. ultrasmedbio.2019.10.010. Epub 2019 Nov 26. PMID: 31780239.


This article is a reprint of a previously published article. For citation purposes, please use the original publication details: Journal of Vascular and Interventional Radiology, 33(9), pp. 1021–1024.


DOI of original item: dx.doi.org/10.1016/ j.jvir.2022.05.011.


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