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OMC III, Module II > 9. MRI > Flashcards

9. MRI Flashcards

1
Q 
MRI- Simplified
• The patient is placed in a \_\_\_\_
• A radio wave is sent in
• The \_\_\_\_ wave is turned off
• The patient emits a signal which is received and used for : • \_\_\_\_ of the picture
A

magnet
radio
reconstruction

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2
Q

MR units: magnets

  1. ____ 0.1-0.3 T
  2. Resistive 0.02-0.4T
  3. ____ 0.3-4.0T(cooled with liquid nitrogen and helium)
  4. 1T = 10000G( Gauss)
  5. Earth’s magnetic field : 3-6 G
  6. Commonly used MR magnets: 0.5-1.5 T

Measured in ____

A

permanent
superconductive
teslas

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3
Q

Neck - mid sagittal

Typical sagittal shots
• Photoshopped and pressed invert button to give us catscan of same image (LOOK AT TRANSCRIPTION)
○ Mandible opacified area is cortex in Catscan
○ Mandible is now inverted so bone is ____ on MRI!
When get to joint and TMJ, we typically use more catscan but now we are shifting more to MRI
Critical area to reinforce what bone is
• In spine: marrow is ____ where cortex is now ____

Now looking upwards: nose to toes where we see cerebellum, turbinate’s and sinus
Can see condyles through angulation - now we can see all musculature (pterygoids, masseter, etc.)

A

black
highlighted
black

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4
Q

Ethomid sinusitis, maxillary sinusitis

Concha with uniform bright ____ in maxillary sinus (may have soft tissue)
Bone here is ____

A

lesion

dark

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5
Q

Ameloblastoma: T1 weighted images of images

Ameoloblastoma: benign, very aggressive, single or multilocular, can be cystic

This looks like ____ ameloblastoma with line around it
• Some facial swelling

Can see teeth that look like extraction sockets - ____ structures with dentin and enamel

A

cystic

opacified

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6
Q

Coronal T2W image w/ contrast

____ put in to isolate tumor/lesion
• Can see bands of ____ are amazingly highlighted so you can see even convolutions in brain (not focus though)

A

contrast

soft tissue

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7
Q

OKC - ramus Fat suppressed MR T1W before and after contrast

Even on MRIs, can tweak algorithm:
• CATSCAN can do maximum ____ and reconstructive
algorithms
• Can do same thing with ____

○
Can remove ____ tissue (fat suppressed)
Fibrous osseous tissue with patient who is very swollen compared to normal side (where big star is)

HARDLY ANY DIFFERENCE BT ____ AND ____

A

intensity
MRIs
dentin/enamel
air

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8
Q

OKC: coronal T1W fat suppressed and T2W MR

Fat suppressed: orchestrated in formulas so you can see either ____ tissue window, ____ window, ____ suppressed (remove fat so you are not seeing it as clearly)
• Gives our eyes a different way (adipose tumor that will suppress fat and lose tumor)

&laquo_space;in area of parotid, benign but significant excision needed to remove that (do not have to know disease name although he did identify it)

T1: amount of timing of ____ that they use for each version
• Tweak machine to angulate and orchestrate ____
molecules on a T1 and T2

T1 and T2 often pick up different features

A 
soft
bone
fat
magnetism
water
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9
Q

Odontigenic Myxoma D/D w/ CEOT Ameloblastoma

CEOT: calcifying ___ ossifying tumor
• Very ____ - either water or fat in there
Here you can see masseter out here
Can see pulp in this slice

A

bright

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10
Q

Squamous Cell Ca of mandibular gingiva-left (*) Arrow shows enhancement of mandibular nerve (involved)

Down in region where arrow is
• Right side = black is ____, greyish area is ____ and black
area is tooth, sinuses
• LEFT SIDE: asterisk - bone cortex is here but marrow is
different on left compared to right (more radiodense - ____ arrow)
○ In buccal space area we have signal coming back that is opaque so more ____ there than should be (soft tissue tumor)

A

cortex
marrow
white
tissue

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11
Q

Appearance of various tissues in T1 & T2W images

Tissue
T1W:
T2W:

Water
T1W:
T2W:

Fat
T1W:
T2W:

Fibrous tissue
T1W:
T2W:

Organs
T1W:
T2W:

Tumors
T1W:
T2W:

Fresh blood
T1W:
T2W:

Old blood
T1W:
T2W:

Air
T1W:
T2W:

Bone, calcium
T1W:
T2W:

A

DARK
VERY BRIGHT

DARK
DARK

(everything else is pretty similar/the same)

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12
Q

Normal appearance

NOW TMJ ANATOMY ON MRI’S
• Missing slide: closed and open
○ CLOSED:
• Condyle sitting nicely in glenoid fossa
• Disk is ____ when condyle is in reprose in glenoid fossa normally (closed)
• Little bit of banding at top and then rest of it goes anterior underneath articular eminence
• Lateral pterygoid is superior and inferior
• Bilateral zone is compressed
• Once we are open though
○ OPEN:
• Articular eminence has ____ follow down slope
• Disk is locked anteriorly - may hear ____ (cannot tell what is happening in normally contoured condyle with soft tissue issues on regular panoramic or catscan
• Can tell by ____ or clinically

A

superior anterior
condyle
click
MRI

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13
Q

T1 w sagittal MR view

• ____ of the condyle
• ____ of the disc relative to
the position of condyle
• Assess the joint space in these images- closed and open

CAN ONLY SEE JOINT ON ____
• Best image to assess condyle, TMJ pathologies!

A

position
position
MR

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14
Q

Sagittal T1W Mr

  • ____ position and shape
  • ____ and shape
  • Cortical border of ____
  • ____ eminence
A

condylar
disc position
condyle
articular

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15
Q

Anterior disc displacement

____ is not completely smooth, is that causing
issues with opening

Disk looks like its going beyond ____ which could be reason why patient is having pain or experiencing issues opening ja

A

condyle

articular eminence

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16
Q

T2W/proton density sagittal images showing eroded condylar head. psoriaric arthritis

Now proton modification with machine
• Articular eminence is stretched out but ____ bone we see (want it to be smooth) meaning degenerative changes (disk or condylar head)
• Any ____ from punched or sports, push into joint leading
to ____ can be one cause of this
• Can also just be arthritic changes

A

irregular
trauma
hemarthrosis

17
Q

Coronal view: Shepard’s Hook! Osteo Arthritis

____ growths (even though growing outward) still degenerative and not healthy
• Irregular
• Is patient symptomatic?
Does it require surgical intervention to recountour and clean out regeneration

A

expohytic

18
Q

Bird beaking: classic OA/Disc displacement

Sagittal view
• Bird beaking - seen on conventional ____ as well
○ Degenerative usually ____
○ Irregular on condylar head - can catch or hook onto
disk
○ Doing opening and closing, lateral and coronal views
to see movement

A

panoramic

osteoarhritis

19
Q

This is how ____ tumors are on T1Ws: a case of synovial chondromatosis showing intermediate signals from the R condylar area

Now moving away from TMJ but within ____ capsule you can get tumors in there as well - not very good prognosis lesions to get

A

bright

synovial

20
Q

Silastic implants for disc replacement. Sagittal CT soft tissue window

Sometimes we have to replace what is up there with new condyle (____) or get little template like silastic disk (____) to allow remnant of condyle to translate along articular eminence
MRI more challenging to look at
• Bony lesion of anything including TMJ = lean more towards ____ or ____
○ But medical CT has much more ____ so put in perspective
• Thinking more soft tissue and disk displacement type of issues or even myofacial pain in oral medicine = ____ (open, close, coronal, lateral)
○ Will not typically use ____ for MRI

A

reconstruction
artificial

cone beam
medical CT
radiation
MRI
contrast

OMC III, Module II (10 decks)

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