Enhance Study Quality

With Saline

Improve study quality, lower costs and reduce streaking in the chest and neck with saline

 

Proper use of power-injected saline in CT leads to better, and more accurate study results.

The use of nonionic contrast agents is quickly becoming mainstream. These agents are often preferred because they are tolerated better by patients and because the complications associated with contrast extravasation tend to be less severe.

The downside of using these agents is their nephrotoxic effects and their cost. This has forced radiologists to come up with ways to minimize the overall volume of contrast administered.1

These advances have prompted research into how to consistently administer the “optimum bolus” of intravenous contrast to maximize contrast enhancement and minimize dosage, all within the confines of shorter scan times.

The shape of injected contrast bolus can be tailored to achieve a desired enhancement pattern.2 Contrast medium is generally administered at a constant injection rate (uniphasic rate) injection protocol.

The second most commonly utilized injection bolus shape is a biphasic-rate injection, which is a fast constant-rate injection followed by a slow constant-rate injection.2

 

Pre-Contrast Test Bolus of Saline Plus Saline Flush

A test bolus injection of saline creates a tight, more compact, bolus,1,2 helps achieve uniform vascular enhancement2,3 and prevents a decrease in contrast material flow.4

With the increasing clinical applications of CTA and double-barrel CT contrast injectors, post-contrast saline flush has become widely accepted in CT imaging to improve the efficiency of contrast medium utilization and may reduce the iodine dose without negatively affecting the level of contrast enhancement.

In order to deliver all of the contrast from the venous circulation into the heart in one efficient, tight and coherent bolus, use of saline flush is recommended.1

In fact, several studies have demonstrated that, depending on the type of examination—abdominal, thoracic or CT angiographic—if the saline flush technique is used, approximately 15 to 50 mL of contrast material can be saved.1

A saline flush can permit optimal adjustment of contrast bolus geometry,1-3 reduced pooling of contrast in arm veins,1 decreased streak artifact,1,5 and the ability to reduce iodine dose.2,3

This saline flush pushes the tail of the injected contrast medium bolus into the central blood volume and so makes use of contrast medium that would otherwise remain unused in the injection tubing and peripheral veins.2

Therefore, a saline flush increases the efficiency of contrast medium utilization and the level of contrast enhancement. Additional advantages of a saline flush include:

      • improved bolus geometry as a result of reduced intravascular contrast medium dispersion,
      • reduced streak artifact from dense contrast medium in the brachiocephalic vein and superior vena cava on thoracic CT studies, and
      • increased hydration to reduce contrast-induced nephrotoxicity

Injection of contrast material followed by a saline solution bolus using a double-syringe injector allows a 20% reduction of contrast material to 60 mL with a similar degree of enhancement.1

 

References:
1. Auler MA, Heagy T, Aganovic L, Brothers R, Costello P, and Schoepf UJ. Saline chasing technique with dual-syringe injector systems for multi-detector row computed tomographic angiography: rationale, indications, and protocols. Curr Probl Diagn Radiol. 2006 Jan-Feb;35(1):1–11.
2. Bae KT. Optimization of contrast enhancement in thoracic MDCT. Radiol Clin North Am. 2010 Jan; 48(1): 9–29.
3. Bae KT. Intravenous contrast medium administration and scan timing at CT: considerations and approaches. Radiology. 2010 Jul; 256(1): 32–61.
4. Cademartiri F, van der Lugt A, Luccichenti G, Pavone P, and Krestin GP. Parameters affecting bolus geometry in CTA: a review. J Comput Assist Tomogr. 2002 Jul–Aug; 26(4): 598–607.
5. Haage P, Schmitz-Rode T, Hübner D, Piroth W, and Günther RW. Reduction of contrast material dose and artifacts by a saline flush using a double power injector in helical CT of the thorax. AJR Am J Roentgenol. 2000 Apr; 174(4): 1049–1053.
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