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Diagnostic M.'s Sara Peer mentor > Chapter 22: MRI - Understanding The Principles And Recognizing The Basics > Flashcards

Chapter 22: MRI - Understanding The Principles And Recognizing The Basics Flashcards

1
Q

What does a Musculoskeletal MRI scan for?

A 
Menisci = tears
Tendon injuries
Bone marrow contusion; occult of stress fractures
Muscles
Osteomyelitis
Spine = disk disease, scarring
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2
Q

What does a Neurologic MRI scan for?

A

Brain = post. fossa, tumor, infarction, MS

Peripheral Nerves = impingement

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3
Q

What does a GI MRI scan for?

A

Liver = lesions, cysts, cancer
Biliary System = Ductal dilation
Small and Large Bowel = appendicitis in pregnant females

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4
Q

What does an endocrine/reproductive MRI scan for?

A

Adrenal glands = adenomas and hemorrhage
female pelvis = uterus, ovaries, cancer, cysts, endometriosis
Male pelvis = rectal, bladder, and prostate cancer staging

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5
Q

What does a Genitourinary MRI scan for?

A

Kidneys = renal masses and cysts

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6
Q

What does the strong magnetic field of an MRI influence?

A

Hydrogen nuclei/protons

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7
Q

What direction do the protons align when placed into a powerful magnet such as an MRI?

A

They align with the external magnetic field instead of their own minimagnetic field

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8
Q

What displaces the protons from their original alignment with the external magnetic field of the scanner?

A

Radiofrequency pulses transmitted by the transmitter coil

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9
Q

What is produced when the RF pulse is turned off and the displaced protons relax back to their original alignment with the main magnetic field?

A

an RF signal (echo)

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10
Q

What receives the RF signal (echo)?

A

Receiver coil

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11
Q

What happens to the RF signal once the receiver coil receives its echo?

A

A computer reconstructs the information from the echo to generate an image

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12
Q

What is the main kind of magnet in a MRI?

A

a superconducting magnet cooled to extremely cold temps

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13
Q

What is a pulse sequence? What are the two main ones?

A

Spin Echo (ES) and Gradient recalled echo (GRE)

set of imaging parameters that determine how a tissue will appear

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14
Q

What is T1?

A

longitudinal relaxation time

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15
Q

What is T2?

A

transverse relaxation time

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16
Q

What is TR?

A

repetition time between two RF pulses

17
Q

What is TE?

A

echo time between a pulse and its resultant echo

18
Q

What does a short TR produce?

A

T1

19
Q

What does a long TE produce?

A

T2

20
Q

What appears bright white on images in a T1-weighted MRI?

A 
Fat
Hemorrhage
Proteinaceous Fluid
Melanin
Gadolinium
21
Q

What appears bright white on images in a T2-weighted MRI?

A 
WATER
Fat
Edema
Inflammation
Infection
Cysts
hemorrhage
22
Q

Fat is…

A

T1-bright and T2-bright

23
Q

Water is…

A

T1 dark and T2 bright

24
Q

What is suppression?

A

feature of MRI that cancels out signals from certain tissues; most often used for fat on T1-fat supressed images

25
Q

What is fat suppression useful for?

A

tissue characterization after administering gadolinium

26
Q

What is the most common IV contrast used in MRI?

A

Gadolinium

27
Q

What is the effect of Gadolinium?

A

shortens T1 relaxation time causing a brighter signal

Vascular structures, tumors, and areas of inflammation are enhanced

28
Q

What must you obtain before taking an MRI of a patient suspected of having metal objects in eyes?

A

you must get an orbital xray

29
Q

What cannot go near an MRI machine?

A

ferromagnetic objects

30
Q

What stage of pregnancy can an MRI be taken in?

A

Second and Third Trimester

31
Q

Can you use Gadolinium in a pregnant patient?

A

NO

32
Q

What is Nephrotic Systemic Fibrosis?

A

debilitating fibrotic disease which occurs if patient with renal insufficiency receives Gadolinium

AVOID GADOLINIUM IN RENAL DISEASE PATIENTS

Diagnostic M.'s Sara Peer mentor (27 decks)

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