Week 1: Intro, Power injector and communication

Question 1

Limitations of general radiography

Answer 1

• Superimposition
• Unable to distinguish between 2 similar tissues

Question 2

Advantages of CT

Answer 2

• Eliminate Superimposition
• Differentiate small differences - Image Quality

Question 3

Window Setting for the Brain

Answer 3

WW= 100, WL=30

Question 4

Window Setting for Soft Tissue

Answer 4

WW: 350-500, WL: 50

Question 5

Window Setting for the Lungs

Answer 5

WW= 1500, WL= -600

Question 6

Window Setting for the Liver

Answer 6

WW= 150, WL=30-70

Question 7

Window Setting for Pelvic Bone

Answer 7

WW= 1800-2000, WL=400-600

Question 8

What does the number of pixels do

Answer 8

determines the resolution of the image by being signed a number

Question 9

What does more pixels do to a CT image?

Answer 9

gives higher resolution and better image quality

Question 10

How is depth of an image determined

Answer 10

by slice thickness

Question 11

How is a voxel determined

Answer 11

by the pixel area and slice thickness

Question 12

What does a Voxel Represent

Answer 12

a volume of tissue within the patient

Question 13

What does Siemans call preliminary image (Scout, tomogram etc)

Answer 13

Topogram

Question 14

What does GE call preliminary image (Scout, tomogram etc)

Answer 14

Scout

Question 15

What does Toshiba call preliminary image (Scout, tomogram etc)

Answer 15

Scanogram

Question 16

Common matrix size

Answer 16

512

Question 17

ipsilateral

Answer 17

on the same side

Question 18

Rostral

Answer 18

towards the nose

Question 19

contralateral

Answer 19

on the opposite side

Question 20

thenar

Answer 20

the fleshy part of the hand at the base of the thumb

Question 21

volar

Answer 21

pertaining to the palm of the hand or the flexor surface of the wrist or sole of the foot

Question 22

Why do we use a power injector

Answer 22

• faster injection time (better contrast enhancement)
  -large bolus injections (single large quantity)
• delivery of precise flow rates
• consistent and easily reproducible injection
• programmable
• can be used for many indications

Question 23

control panel of power injector

Answer 23

displays injection parameters (flow rate, rise, total volume, pressure and delay)

Question 24

power injector syringe

Answer 24

sterile, removable, varying capacities available, can be both reusable and disposable

Question 25

heating device of power injector

Answer 25

thermal sleeve placed over syringe set to 37 degrees. reduces viscosity of contrast and maintains temperature of preheated contrast medium.

Question 26

flow rate

Answer 26

• rate contrast injected
• measured is cc/sec or ml/sec

Question 27

factors affecting flow rate

Answer 27

procedure, vessel, pt type, nature of disease, viscosity of contrast medium (determined by heat or iodine content), catheter, injection pressure

Question 28

total volume

Answer 28

-amount of contrast to be delivered
- flow rate x injection duration (V = cc/sec or ml/sec x sec)
- measured in cubic centimetres

Question 29

rise (linear rise)

Answer 29

time it takes to reach desired flow rate, measured in seconds

Question 30

injection pressure

Answer 30

• force needed for specific dose of contrast medium
• measured in pounds per square inch (psi), range is 100-1200psi
• dependent on size of vascular structure and type of catheter

Question 31

delay

Answer 31

injection delay: allows for image acquisition to begin before contrast injection. useful in angiography imaging.

xray delay: injection of contrast begins before the acquisition of images. useful in lower extremity arteriography