RADIOLOGY - TMJ imaging

Question 1

what are the TMJ imaging modalities?

Answer 1

plain film
CBCT
CT
MRI
Nuclear medicine

Question 2

what are the types of plain films that can be taken to image the TMJ?

Answer 2

panoramic
PA mandible
reverse townes
lateral oblique

Question 3

when would an OPT be indicated for TMJ assessment?

Answer 3

recent trauma
change in occlusion
mandibular shift
sensory/ motor alterations
change in range of movement

Question 4

what bones make up the TMJ?

Answer 4

condylar head of the mandible
articular eminence and temporal fossa of the temporal bone

Question 5

what muscles are associated with the TMJ?

Answer 5

temporalis
masseter
pterygoids
digastric
stylohyoid
mylohyoid
geniohyoid

Question 6

where does the condylar head lie?

Answer 6

within the joint space

Question 6

what sits superior to the condylar head?

Answer 6

glenoid fossa

Question 7

what lies superior to the glenoid fossa?

Answer 7

middle cranial fossa

Question 8

what is continuous to the glenoid fossa anteriorly?

Answer 8

eminence of temporal bone

Question 9

what lies posterior to the condylar head?

Answer 9

styloid process and mastoid air cells

Question 10

what lies laterally to the condylar head?

Answer 10

external auditory meatus

Question 11

what lies anterior to the condylar head?

Answer 11

2 heads of the lateral pterygoid muscle

Question 12

what are the 2 heads of the pterygoid muscle?

Answer 12

inferior head
superior head

Question 13

where does the inferior head of the pterygoid attach?

Answer 13

condylar head

Question 14

where does the superior head of the pterygoid attach?

Answer 14

articular disc

Question 15

what part of the articular disc is thicker?

Answer 15

posterior aspect

Question 16

what separates the joint space into its inferior and superior spaces?

Answer 16

articular disc

Question 17

where do the nerve endings for TMJ sensory function lie?

Answer 17

the posterior attachment of retrodiscular tissues

Question 18

what happens when nerve endings of TMJ are stretched?

Answer 18

pain is elicited

Question 19

what plain films can be used to image the TMJ?

Answer 19

Panoramic
PA mandible
reverse townes
lateral obliques

Question 20

what is an issue when plain films are used to image the TMJ?

Answer 20

may get an artificial position of TMJ when pt bites on the bite block

Question 21

what is reverse townes imaging?

Answer 21

an AP view of the mandible with an open bite technique

Question 22

should you take an OPT for TMJ assessment?

Answer 22

in most cases - no

Question 23

when is an OPT for TMJ assessment indicated?

Answer 23

recent trauma
change in occlusion
mandibular shift
sensory/ motor alterations
change in range of movement

Question 24

what signs may you see on a DPT that are indicative of inflammatory arthritis (rheumatoid)?

Answer 24

flat and pointed condylar heads

Question 25

in what cases would a CBCT be taken for trauma on A+E?

Answer 25

if unable to stand or has a low GCS

Question 26

what imaging modalities are used for trauma of the mandible/ TMJ?

Answer 26

OPT/ panoramic PA mandible reverse townes

Question 27

what is a guardsman #?

Answer 27

bilateral condylar # + mandibular symphysis #

Question 28

why is the midline hard to see on a PA mandible?

Answer 28

superimposition of the cervical spine

Question 29

what would CBCT be used for in relation to imaging the TMJ?

Answer 29

bony changes - degenerative bone disease e.g., osteoarthritis

Question 30

what will be present on a CBCT of a pts TMJ with osteoarthritis?

Answer 30

sclerosis and remodeling - a lot of joint space and irregular margins

Question 31

what is the disadvantage of using CT over CBCT?

Answer 31

increased radiation dose

Question 32

when would you use CT rather than CBCT for TMJ imaging?

Answer 32

when want to visualise soft tissue and bone - neoplastic masses

Question 33

what is the gold standard imaging technique for TMJ?

Answer 33

MRI

Question 34

advantages of MRI?

Answer 34

no radiation dose soft tissue and bony pathology

Question 35

what is MRI good for imaging relating to the TMJ?

Answer 35

Articular disc position - open and closed

Question 36

what 2 views are used to check position of the disc when taking an MRI?

Answer 36

coronal and parasagittal along axis of condyle

Question 37

what colour is cortical bone on an MRI?

Answer 37

black

Question 38

what colour is cancellous bone on MRI?

Answer 38

white

Question 39

symptoms of anterior disc displacement with reduction?

Answer 39

click on opening

Question 40

describe anterior disc displacement with reduction?

Answer 40

disc is sitting anterior when mouth closed disc clicks back to normal position when mouth opened

Question 41

symptoms of anterior disc displacement without reduction?

Answer 41

limitation of opening with pain

Question 42

why is pain elicited with anterior disc displacement without reduction?

Answer 42

the retrodiscular tissues stretch

Question 43

what may be present on MRI with anterior disc displacement and bony arthritis changes?

Answer 43

loss of joint space and changes to condylar head appearance

Question 44

what is SPECT?

Answer 44

single photon emission CT nuclear medicine for TMJ imaging

Question 45

what is injected for SPECT imaging?

Answer 45

IV Technetium 99-metastable (radio-isotope) *half life 6.5 hours

Question 46

what is SPECT used for?

Answer 46

condylar hyperplasia

Question 47

what will show on SPECT scans when there is condylar hyperplasia?

Answer 47

hot spots in areas of increased metabolic activity

Question 48

give examples of benign tumours which may affect the condylar head?

Answer 48

osteochondroma osteoblastoma isolated region of fibrous dysplasia/condylar hyperplasia

Question 49

tx for condylar hyperplasia?

Answer 49

resection of hyperplastic tissue and distraction osteogenesis to form a new condylar head

Question 50

what is an alternative imaging modality if MRI not feasible due to contraindications?

Answer 50

arthrography (very rarely used)

Question 52

what does arthrography image?

Answer 52

soft tissue - specifically articular disc

Question 52

what can arthrography be used for?

Answer 52

diagnostic and therapeutic purposes e.g., infection of steroids into a space

Question 53

how is arthrography performed?

Answer 53

inject contrast (iodinated) into joint space done under fluoroscopic guidance

Question 54

how does arthrography diagnose disc perforation?

Answer 54

if contrast leaks from lower joint space to upper joint space