MRI week 4

Question 1

the use of magnetic fields and radio waves to obtain a mathematically reconstructed image

Answer 1

MRI

Question 2

the image receptor represents differences among various tissues of the patient in the _ and in the _from the stimulation by radio waves in the presence of a magnetic field

Answer 2

# of the neclei
rate at which these nuclei recover

Question 3

x-ray involves the interactions with the _
MRI involves the _
NOt all nuclei respond to magnetic fields

Answer 3

electrons surrounding the atom

nuclei alone

Question 4

Most imaging is preformed with

Answer 4

hydrogen nuclei (single protons)

Question 5

the body is roughly _ water

Answer 5

85% (soft tissue)

Question 6

what provides the powerful static magnetic field

Answer 6

magnet

Question 7

the strong magnetic field can be measured in units of

Answer 7

Tesla

Question 8

static field strengths surrounding the magnet is called _

sometimes are measured in _

Answer 8

fringe magnetic fields

Gauss

Question 9

one tesla = _ Gauss

Answer 9

10,000

Question 10

open MRI units are now available for those with _ but the units are _ and are _ to basic MRI function

Answer 10

claustrophobic
slower
restricted

Question 11

contraindications of MRI

Answer 11

pacemakers
ferromagnetic aneurysm clips
metallic fragments in eye
cochlear implants
Starr-Edwards pre-6000 model prosthetic heart valve
Internal drug infusion pumps
neurostimulators
bone growth stimulators

Question 12

what is often considered a contraindication in the _ and what needs to be obtained

Answer 12

pregnancy
first trimester
informed consent and clinically documented

Question 13

a pregnant patient would not be given

Answer 13

contrast media gadolinium-DTPA

Question 14

prep for MRI pt

Answer 14

remove all metal objects
analog watches
credit cards

Question 15

In some cases for MRI you must _ the patients

Answer 15

sedate