Other Imagine Modalities - Bony Imaging

Question 1

What are the options for bony imaging? - not normal ones

Answer 1

CBCT or CT
MRI

Question 2

MRI would be used to check for what?

Answer 2

Marrow changes

Question 3

What is CBCT?

Answer 3

-low dose multi-planar imaging
-imaged are made up from isotropic voxels

Question 4

What 3 planes of images do you get from CBCT?

Answer 4

-axial
-coronal
-sagittal

Question 5

CBCT is good at bony imaging but has poor what?

Answer 5

Soft tissue contrast

Question 6

How does CBCT worK?

Answer 6

have panal and x-ray source
move around the pt 360 degrees
Cone-shaped x-ray beam

Question 7

Describe the different planes you get from CBCT.

Answer 7

axial - from feet to head
coronal - straight on
sagittal view - side on

Question 8

Compare CBCT vs CT.

Answer 8

CBCT:
* cone-shaped beam
* low dose
* poor soft tissue contrast
* radiographic contrast not required
* pt sitting upright/standing

CT:
* Fan-shaped beam
* high dose
* good soft tissue contrast (windowing)
* radiographic contrast can be used if indicated (for malignancy/suscepted malignancy)
* pt lying horizontal

Question 9

Indications for CBCT in dentistry?

Answer 9

-impacted teeth/canines/8s
-implant planning
-MRONJ
-Cysts
-odontogenic tumours
-confirm diagnosis of osteomyelitis

Question 10

When is imaging used for TMD?

Answer 10

NOT for myofacial pain

For internal derangement of the disc or for degenerative disease

Question 11

What TMJ imaging is used when it is indicated?

Answer 11

MRI for internal derangement of didc

CBCT for degnerative disease/if considereing joint replacement

Question 12

MRI for internal derangement can determine what?

Answer 12

if displcement is with or without reduction and which direction the disc moves in relation to the condyle (can see the dic well in MRI)

Question 13

What MRI views do you need to view the disc properly in internal derangement?

Answer 13

-para-sagittal view
-para-coronal view

Question 14

MRI can also be used for what?

Answer 14

Facial asymmetry

Question 15

What is radionuclide - SPECT imaging and what is it used for?

Answer 15

-single positron emission CT
-99mgTc used
-checks for activity of TMJ
-ONLY used for screening as has high sensitivity but low specificity

Question 16

When might you use SPECT?

Answer 16

Condylar hyperplasia to see if joint is undergoing active growth

Question 17

What imaging can be used in H&N oncology

Answer 17

-Cross-sectional imagine with contrast (CT/MRI)
-ultrasound guided biopsy of cervical lymphadenopathy
-PET/CT
-OPT - dentally fit

Question 18

CT vs MRI

Answer 18

-MRI no radiation dose
-MRI scan takes significantly longer
-More contraindications for MRI
-MRI better for assessing perineural spread, bone invasion via bone marrow changes, soft tissue characteristics of the lesion

CT done most of the time

Question 19

Contraindications for MRI?

Answer 19

-pacemakers, cochlear implants
-claustrophobic
-tattoos (metal particles can feel like skin is burning)

Question 20

CT contraindications?

Answer 20

Only real contraindication is contrast allergy

Question 21

What is PET scan?

Answer 21

-positron emission tomography

Question 22

Describe how PET works

Answer 22

-radioactive fluroine labelled glucose injected
-goes to metabolically active tissues (like tumours - they need more gluocse to grow quicker)

Question 23

PET scans good for what?

Answer 23

-looking for unknown primary tumours
-good for follow-up and recurrence

Question 24

Disadvanatage of PET scans?

Answer 24

-doesn’t give anatomical detail so need CT or MRI for this
-Goes to any metabolically active muscles so can’t swallow or speak during the scan