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CT Patient Care II
Injection Techniques
Question | Answer |
---|---|
A venous catheter designed to deliver medications and fluids directly into the superior vena cava (SVC), inferior vena cava (IVC), or right atrium (RA) | central venous access devices |
Method of individualizing the scan delay using CM bolus itself to initiate the scan. Uses a series of low-rad'n scans to monitor progress of CM bolus. Once an adequate level of enhance't is achieved, the table moves to the starting level & scanning begins | bolus triggering |
Comparison of a Hounsfield unit (HU) measurement taken within the aorta to that of a measurement taken in the inferior vena cava. Used to assess the phase of tissue enhancement after the IV injection of contrast media | arteriovenous iodine difference |
Air that enters the bloodstream & can occur during an IV inj. Small quantities of air can be absorbed by the body; thus it may never be detected if pts are asymptomatic. But, large ones can cause seizures, permanent neurologic damage, or death. Tech error | air embolism |
A rapid injection of contrast material. A volume of contrast of 50 to 200 mL is injected at a rate between 1 and 6 mL/s. The contrast bolus can be delivered by hand (using syringes) or by a mechanical injection system | bolus injection |
Manipulating the flow rate to change the characteristics of the time-density curves | bolus shaping |
The initial phase that immediately follows an IV bolus injection. In this phase of contrast enhancement, the arterial structures are filled with contrast medium and brightly displayed on the image. Contrast media has not yet filled the venous structures | bolus phase/arterial phase |
Injection technique in which two flow rates are used | biphasic injection |
Injection methods that individualize the scan delay. Two methods exist--the injection of a test bolus and bolus triggering | automated injection triggering |
The leakage of fluid from a vein into the surrounding tissue during IV contrast administration | contrast media extravasation |
Technique used to administer contrast material in which an IV line is initiated and contrast medium is allowed to drip in during a period of several minutes | drip infusion |
Last phase of tissue enhance't after injecting CM. Can begin as early as 2 min after bolus phase or drip infusion. CM is largely emptied from arteries, greatly diluted in veins, & soaked the organ parenchyma. CM equilibrate and decline at equal rate | equilibrium phase/delayed phase |
A special noncoring hooked needle used to access an implantable port | Huber needles |
A rapid injection of contrast material delivered by hand, using syringes | hand bolus |
A single- or double-lumen reservoir attached to a catheter. Reservoir hub is in arm or chest subcutaneous tissue, and catheter is tunneled in vein. No external device is visible. Outline of device may be felt. For long-term intermittent access, i.e. chemo | implantable ports |
Central catheters of a larger caliber than PICCs because they are designed to be inserted into a relatively large, more central vein such as the subclavian or jugular. Usually have 3 ports, open ended, & remain in place for few days to 2 weeks | non-tunneled catheters |
Follows the bolus phase; the CM is still much brighter in the arteries than in parenchyma of organs, but now venous structures are also opacified. Begins approx 1 min after start of bolus inj and lasts only a short time. AKA venous phase | nonequilibrium phase |
The phase of renal enhancement that follows the corticomedullary phase that typically occurs approximately 100 to 120 seconds after the IV administration of a bolus of contrast material | nephrographic phase |
Method of administering iodinated contrast media, intravascularly, using a mechanical injection system that controls the flow rate and volume. Also known as power injection | mechanical injection systems |
Injection technique in which two or more flow rates are used | multiphasic injection |
A long catheter that is inserted through the large veins of the upper arm (i.e., cephalic and basilic veins) and advanced so that its tip is located in the lower third of the SVC | peripherally inserted central catheters |
The point after an IV injection when the contrast agent reaches the highest concentration in the aorta | peak aortic enhancement |
The point after an IV injection when the contrast agent reaches the highest concentration in a specified organ. For organs such as the pancreas, bowel, and bladder occurs about 5 to 15 seconds after peak aortic enhancement | peak organ enhancement |
The phase of enhancement that follows the hepatic arterial phase, which typically begins at 60 to 70 seconds after the IV administration of a bolus of contrast material | portal venous phase |
In context of contrast medium, this refers to contrast medium characteristics, including iodine concentration, osmolality, viscosity, volume, and flow rate | pharmacokinetic factors |
Include the use of hand washing and appropriate protective equipment such as gloves, gowns, and masks wherever touching or exposure to patients' body fluids is anticipated. | standard precautions |
Central venous catheters that are inserted into the target vein (often subclavian) by "tunneling" under the skin. This reduces the risk of infection b/c bacteria from skin surface are not able to travel directly into vein. Ex: Hickman, Broviac, & Groshong | tunneled catheters |
Graphical representation that demonstrates the effect of varying contrast dose on aortic and hepatic contrast enhancement | time-density curve |
Method of individualizing the scan delay that consists of administering 10 to 20 mL of CM by IV bolus injection and performing several trial scans to determine the length of time from injection to peak contrast enhancement in a target region, i.e., aorta | test bolus |
Injection technique in which a single injection flow rate is used | uniphasic injection |