Other Imagine Modalities - Bony Imaging Flashcards
What are the options for bony imaging? - not normal ones
CBCT or CT
MRI
MRI would be used to check for what?
Marrow changes
What is CBCT?
-low dose multi-planar imaging
-imaged are made up from isotropic voxels
What 3 planes of images do you get from CBCT?
-axial
-coronal
-sagittal
CBCT is good at bony imaging but has poor what?
Soft tissue contrast
How does CBCT worK?
have panal and x-ray source
move around the pt 360 degrees
Cone-shaped x-ray beam
Describe the different planes you get from CBCT.
axial - from feet to head
coronal - straight on
sagittal view - side on
Compare CBCT vs CT.
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
Indications for CBCT in dentistry?
-impacted teeth/canines/8s
-implant planning
-MRONJ
-Cysts
-odontogenic tumours
-confirm diagnosis of osteomyelitis
When is imaging used for TMD?
NOT for myofacial pain
For internal derangement of the disc or for degenerative disease
What TMJ imaging is used when it is indicated?
MRI for internal derangement of didc
CBCT for degnerative disease/if considereing joint replacement
MRI for internal derangement can determine what?
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)
What MRI views do you need to view the disc properly in internal derangement?
-para-sagittal view
-para-coronal view
MRI can also be used for what?
Facial asymmetry
What is radionuclide - SPECT imaging and what is it used for?
-single positron emission CT
-99mgTc used
-checks for activity of TMJ
-ONLY used for screening as has high sensitivity but low specificity
When might you use SPECT?
Condylar hyperplasia to see if joint is undergoing active growth
What imaging can be used in H&N oncology
-Cross-sectional imagine with contrast (CT/MRI)
-ultrasound guided biopsy of cervical lymphadenopathy
-PET/CT
-OPT - dentally fit
CT vs MRI
-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
Contraindications for MRI?
-pacemakers, cochlear implants
-claustrophobic
-tattoos (metal particles can feel like skin is burning)
CT contraindications?
Only real contraindication is contrast allergy
What is PET scan?
-positron emission tomography
Describe how PET works
-radioactive fluroine labelled glucose injected
-goes to metabolically active tissues (like tumours - they need more gluocse to grow quicker)
PET scans good for what?
-looking for unknown primary tumours
-good for follow-up and recurrence
Disadvanatage of PET scans?
-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
