CT Instrumentation part 3

Question 1

What year did the first CT scanner appear?

Answer 1

1970

Question 2

When did the first CT Injector appear?

Answer 2

1984

Question 3

The Pressure in _____ must exceed the resistance from the pipe and fluid. (tubing, reservoir/syringe, bath tube, pressure gage)

Answer 3

Reservoir/Syringe

Question 4

A smaller diameter catheter requires ____ pressure to make fluid move. (lower, same, higher, no)

Answer 4

higher

Question 5

If the pressure in the reservoir or syringe reaches 100psi what would the pressure at the end of the catheter be if the fluid is flowing freely? (100psi, 50psi, 1000psi, 0psi)

Answer 5

0 psi

Question 6

What are some of the benefits of power injectors over hand injectors?

Answer 6

tight bolus, precise timing, consistency & reproducibility, time & cost savings

Question 7

What is the formula to calculate flowrate through a pipe?

Answer 7

flowrate = reservoir pressure / pipe and fluid resistance

Question 8

With Laminar flow do all of the “layers” of the fluid flow at an equal rate in a pipe?

Answer 8

No, friction causes the layers next to the walls at a slower rate than the unhindered center layers

Question 9

Are you more likely to get turbulent flow with a large or small diameter pipe?

Answer 9

A smaller diameter pipe is more likely to result in turbulent flow because of increased friction.

Question 10

How would you achieve an equivalent flow rate when using a smaller diameter pipe?

Answer 10

Increase reservoir pressure

Question 11

The pressure in _____ must exceed the resistance from the pipe and fluid. (tubing, reservoir/syringe, bath tube, pressure gauge)

Answer 11

Reservoir/Syringe

Question 12

A smaller diameter catheter requires _____ pressure to make fluid move. (lower, same, higher, no)

Answer 12

higher

Question 13

If the pressure in the reservoir/syringe reaches 100psi what would the pressure in the end of the catheter be if the fluid is flowing freely?

Answer 13

0psi

Question 14

What is the advantage or a “tight bolus”?

Answer 14

there will be less dilution with blood and therefore the enhancement will be better

Question 15

Does IV contrast cross into cell membranes?

Answer 15

No, it mixes in with the blood plasma

Question 16

What is the difference between ionic and nonionic Iodinated contrast?

Answer 16

It is related to viscosity and the chemical bond used. Essentially it is related to the number of iodine atoms or particles per the volume.

Question 17

Which type of iodinated IV contrast is better tolerated by patients? (ionic vs non-ionic?

Answer 17

Non-ionic

Question 18

Name three things that affect the viscosity of IV contrast.

Answer 18

molecular structure, molecular weight, and temperature

Question 19

Why do we use warmers on our CT injector syringes?

Answer 19

To make the fluid flow more easily.

Question 20

How many HU (housnsfield units) does it take to appriciate a difference in density?

Answer 20

10 HU

Question 21

The liver receives its blood supply from two sources: the hepatic artery and the portal vein. What percentages are attributed to each?

Answer 21

Hepatic artery is 25% and the Portal Vein in 75%

Question 22

Do tumors within the liver receive their blood supply from the hepatic artery, the portal vein, or a mixture of the two?

Answer 22

Almost exclusively from the hepatic artery.

Question 23

What are the three phases of liver enhancement?

Answer 23

Aterial Phase (aka Blous phase), the Portal Venous Phase (aka the non-equilibrium phase), and finaly the Equilibrium Phase (aka the Delayed Phase).

Question 24

What is the risk of getting the timing wrong on a tri-phasic liver exam?

Answer 24

Abnormalities could be potentially masked

Question 25

Superior Image Quality, Increase patient safety, Decrease per patient cost, and increase throughput are all characteristics of what kind of injector?

Answer 25

A dual head injection that can do Saline as well as Contrast

Question 26

Will you get a better peak enhancement by using contrast alone or with a saline flush?

Answer 26

with a saline flush

Question 27

True/False - Using a pretest saline flush can improve patient safety

Answer 27

True - a test saline injection done at the same rate as the intended contrast injection can test the integrity of the vessel

Question 28

When all is said and done, how much potential contrast is wasted by being left in the tubing and veins when not using a saline flush?

Answer 28

As much as 25 cc

Question 29

What situation would you want to use a simultaneous injection where the saline and contrast are actually mixed and injected simultaneously?

Answer 29

Cardiac Imaging

Question 30

Dual flow (simultaneous) injection makes it possible to (visualize both the right and left sides of the heart, visualize the right coronary ateries, have uniform enhancement that contribultes to more efficient 3D rendering or D: All of the above)

Answer 30

All of the above

Question 31

Has it been proven that contrast can cross cell membranes?

Answer 31

No it has not.

Question 32

What happens to PSI when you change the temperature of the fluid?

Answer 32

When the fluid temperature is raised (such as with contrast warmers) you reduce the amount of PSI required to push the fluid.

Question 33

What can happen if you increase the temperature of the solution from room temperature (20 - 25C) to body temperature (37C).

Answer 33

Decrease Viscosity

Question 34

Using a test injection of saline at the same flow rate used for the contrast in the beginning, can help reduce serious extravisations. (T,F)

Answer 34

True

Question 35

All intravascular contrast media are based on what kind of benzene ring?

Answer 35

A tri-iodinated benzene ring

Question 36

The 1st 40 slice CT scanner was introduced at RSNA in what year?

Answer 36

2003

Question 37

The 1st 64 slice CT scanner was introduced at RSNA in what year?

Answer 37

2004

Question 38

To overcome resistance for Hypaque 60%, the pressure should be set to:

Answer 38

170 PSI

Question 39

Ionic concentration of the dissolved substances per unit of solvent is the definition for what?

Answer 39

Osmolality

Question 40

The concentration of osmotically active particles in solution is known as what?

Answer 40

Osmolarity

Question 41

The longest duration of the 3 phases, below 10 HU difference, and persists until contrast is completely excreted are all characteristics of what phase of a dynamic liver?

Answer 41

Equilibrium Phase

Question 42

As osmolality increases, side effects ______.

Answer 42

Increase