Saline chaser

Saline chaser Less contrast medium Decreased streak artifact at origin of great vessels Greater absolute difference in attenuation Requires potentially expensive specialized dual head CT power injectors... 

Contrast Administration. The cine acquisition of CTP forms the final step in the acute stroke imaging evaluation. With dynamic, quantitative CTP, an additional contrast bolus of 35 5 mL is administered via power injector (at a rate of 7 mL/s), with a saline chaser of 20 0 mL at the same injection rate. The contrast used should be of high concentration, typically 350-370 g/dL of iodine, for optimal signal-to-noise ratio for perfusion maps calculation. 

C-arm CT images may not only suffer from motion artifacts, but also from streak artifacts caused by any dense objects, such as the catheter or high concentrations of contrast media. Ideally, the system is set up as in conventional CT with an automated two-syringe contrast injector that injects either diluted contrast media or at slow flow rates at a predefined time point ahead of the acquisition followed by a saline chaser bolus. This delay time between the contrast injection and the acquisition is essentially necessary to order to enhance the liver parenchyma and flush the arteries with saline. 

Doric PJ, Lee FT Jr., Henseler KP et al (2003) Shock SA. Using a saline chaser to decrease contrast media in abdominal CT. AJR Am J Roentgenol 180 929-934 Fenchel S, Fleiter TR, Merkle EM (2002) Multislice helical CT of the abdomen. Eur Radiol 12 S5-S10 Ferrucci JT (1991) Liver tumor imaging current concepts. Keio J Med 40 194-205... 

Fig. 4.8 Use of a saline bolus chaser b, dashed line) results in a greater maximum enhancement and a slower delay in washout when compared to the standard bolus (a, solid line). The rectangle shows the ideal enhancement...

The surfactant chosen was Chevron Chaser GR-1080, a proprietary commercial mixture of surfactants proven to form effective mobility control foams in high salinity and hardness conditions, and in the presence of crude oil [11]. The surfactant concentration was kept at 0.5 wt% throughout the experiments. 

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