Diagnostic Imaging of the Temporomandibular Joint Flashcards
1
Q
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Diagnoses with Similar Symptoms
A
· Migraine Headache
· Tension Headache
· Temporal arteritis
· Ear infection
· Sinus infection or tumors
· Tooth infection
· Facial muscle spasm
· Jaw joint sprain
· Neuralgia
· Oral cancer
· Jaw joint tumors
· Dental malocclusion
· Jaw joint disk displacement *
· Jaw fracture
2
Q
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Imaging Technique Selection
depends on:
(6)
A
- Clinical diagnosis
- Desire to image hard vs soft tissue
- Diagnostic information provided from
the imaging technique (i.e. visualization
of disc; or range of motion) - Availability
- Radiation dose (aka histologic cost)
- $ Cost
3
Q
Diagnostic Imaging of the
Temporomandibular Joint
(8)
A
*2D Imaging – skull radiography
*Panoramic
*CBCT
*MRI
*Arthrography
*Ultrasound
*Nuclear Medicine
*PET-CT
4
Q
I. Imaging Techniques for Osseous Structures
* 2D skull imaging
(4)
A
- Panoramic (has replaced 2D(skull) imaging – transcranial, transorbital, transpharyngeal, submental vertex)
- CBCT (preferred CT technique for dentistry)
- MDCT
5
Q
II. Imaging Techniques for Soft Tissue Structures
(3)
A
MRI
* Arthrography
* Ultrasound
6
Q
III. Imaging Techniques for Metabolic Activity
(2)
A
- Nuclear Medicine
- PET-CT
7
Q
2D Skull Radiography
Advantages:
(3)
A
- Readily available and accessible health care modality
- Broad anatomic region imaged to evaluate the TMJ,
mandible, maxilla, paranasal sinuses, and skull base in one
radiograph. - Relatively low dose of ionizing radiation
8
Q
2D Skull Radiography
Disadvantages:
(2)
A
- Limitations include: magnification, superimposition of all
dense skull anatomy - Lacks fine anatomical detail
9
Q
PA Skull
A
Beam is 900 to sensor and
parallel to mid-sagittal skull
plane
Mid-sagittal skull plane is
900 to sensor
10
Q
Panoramic Radiography
Advantages:
(5)
A
- Simple and quick to perform.
- Broad anatomic region imaged to evaluate the TMJ,
mandible, maxilla, maxillary sinuses, teeth and
periodontium in one radiograph. - Excellent for identifying fractures, gross degenerative
changes in the TMJ, & gross pathological changes of the
maxilla & mandible. - Relatively low dose of ionizing radiation.
- Ideal for patient who cannot open his/her mouth
11
Q
Panoramic Radiography
Disadvantages:
(3)
A
- Limitations include: magnification, superimposition, &
inherent distortion. - Lacks fine anatomical detail.
- Ghost image artifact radiopaque shadows superimposed over
normal anatomic structures. This results from projection of x-
ray beam through a dense object (i.e. spinal column, hard
palate)
12
Q
1 day background radiation ~
A
8.5μSv
13
Q
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Condylar Hypoplasia of traumatic origin on R condyle resulting in
A
loss of
vertical height on mandibular ramus. Hx of fracture of R condyle at age 6.
14
Q
Panoramic TMJ Projections
(2)
A
- A special module
available on most
contemporary TMJ
units - Panoramic TMJ
projections can be
taken in closed,
protruded and open
positions
15
Q
Cone Beam Computed Tomography
(4)
A
- Introduced in oral &
maxillofacial
imaging in 2001 - Utilizes relatively
low ionization
radiation - Multiplane (3D)
visualization of hard
tissues - no visualization of
soft tissues
16
Q
Cone Beam Computed Tomography
(4)
A
- Introduced in oral & maxillofacial imaging in 2001
- Utilizes relatively low ionization radiation
- Multiplane (3D) visualization of hard tissues
- no visualization of soft tissues
17
Q
CBCT Advantages
(6)
A
- Controlled
magnification - Lack of
superimposition - Absence of
geometric distortion - Multiplanar & 3D display
- Ease in data acquisition,
reconstruction & display - Improved structure
visualization &
diagnostic efficacy
18
Q
TMJ Articular Disorders
A
- Non-Inflammatory (DJD, OA)
19
Q
Early Remodeling Changes
(5)
A
- temporal fossa and condylar
process demonstrate intact
cortices with physiologic thickness. - trabecular patterns are within
physiologic limits - Right - mild flattening of the
condylar articular cortex - Left – mild flattening of medial side
of condylar articular cortex - condylar processes are slightly
posteriorly displaced in the
temporal fossa in the closed
mandibular position. The posterior
positioning increases the joint
spaces.
20
Q
On the open view, the condylar processes translate to
positions just posterior to the crest of the articular eminence
* this indicates
A
slight limitation to the range of condylar
translation
21
Q
Impression:
Bilateral physiologic remodeling with evidence of
degenerative joint disease. The lack of consistent cortication in the
left TMJ is indicative of active —.
A
osteoarthritis
22
Q
Multi-Detector Computed Tomography
(MDCT)
a.k.a.
(4)
A
- Multislice CT (MSCT)
- Multidetector Helical CT
- Multirow CT
- Multirow Helical CT
23
Q
Images constructed in the anatomic
planes of imaging;
(3)
A
- Coronal (frontal)
- Axial (transverse)
- Sagittal
24
Q
MDCT
(4)
A
- X-ray tube & detector revolve around patient
and data is stored in computer - Similar hard tissue pathology in sinuses, TMJ,
head and neck as CBCT - Not useful in evaluation of disc displacement
due to poor reliability of imaging the disc and
superiority of MRI - Pt receives higher dose of radiation
compared to dental CBCT due to larger Field
of view (FOV)
25
Computed Tomography (CT)
* ADVANTAGES
(4)
* Eliminates superimposition of images of structures
superficial/deep to area of interest
* Differentiates between tissues easily due to high-
contrast resolution and “windowing” ability
* Stored images are reconstructed in axial, coronal &
sagittal planes from a single imaging procedure
* Better insurance benefits (maybe)
26
Disadvantages of C.T.
(3)
1) High dose of ionizing radiation
2) Expensive and not as readily available as
conventional imaging
3) Sensitive to artifacts from metallic
restorations and patient movement
27
Magnetic Resonance Imaging
(MRI)
* One of the most important advantages MR
has is the ability to
separate tissues with
extracellular water from cellular tissues
with intracellular water
28
Components of
Magnetic Resonance Imaging
(MRI)
(3)
1. Magnets
2. Resonant energy
3. Imaging
29
MRI System
(2)
Image Capture
Image Processing
30
Experiences for the Patient
(3)
* Confined space
* “Clanging” noise
* Mild vibration and movement
31
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TMJ Articular Disorders
* Disc Derangements
(6)
1 - No evidence of Internal Derangement (NID)
Normal
2 - Meniscal (Disk) Displacement with Reduction
3 - Meniscal (Disk) Displacement without
Reduction
4 - Meniscal (Disk) Displacement without
Reduction Associated with Perforation
5 - Meniscal (Disk) Displacement without
Reduction and Perforation and Degenerative
Joint Disease
6 - Ankylosis
32
Magnetic Resonance Imaging
Advantages of the M.R.I.
(3)
1) No ionizing radiation
2) Best soft tissue imaging;
suspected articular disc disorders, particularly
disc displacement, edema, perforation, soft
tissue adhesions, & tumors
3) Physically painless
33
Disadvantages of MRI
(5)
1) Sensitive to motion artifacts
2) Expensive financial and temporal demands
3) Claustrophobia
4) Psychologically difficult to tolerate
5) Disc displacement is over diagnosed with
15 -35% false- positive findings
34
MRI Concluding Comments
* Best modality to study soft tissue disease; --- most common imaging sequences to evaluate
change in soft tissue structures
* Functional studies of ...
* Poor reliability in depicting ---
* MRI accuracy is no greater than clinical
examination for detecting ---
T1 and T2
fluid dynamics in vascular
channels
disc perforation
disc displacement
without reduction
35
Arthrography Tray Armamentarium
Arthrography of TMJ Synovial
Spaces is best imaging for
meniscal perforation
36
Arthrography
* What is it
* TMJ uses are 3
* Functioning of condyle/disc relationship can
be assessed with use of 2
| r
radiographic contrast medium is injected into
the inferior/superior joint synovial space(s)
and the fill pattern is evaluated
radiographically; primarily with tomography
disc position, meniscal/disk
perforation and fibrosis
fluoroscopy and
videotaping.
37
Arthrography
Limited use at present due to wide
availability of
* Use on selected patient cases when
dynamic imaging results will alter the
course of treatment or when indicated
prior to ---
* Most reliable method for identification of
---
MRI and patient
discomfort
joint lavage
perforation in the articular disc.
38
Arthrography
Disadvantages
(4)
* Invasive
* Ionizing radiation
* Discomfort due to injection of contrast medium
* Possible hypersensitivity to contrast agent
39
Ultrasound of Normal TMJ
(4)
* Low financial cost
* Less invasive
* Detects fluid in the joint space
* Can be evaluated in open and closed
jaw positions
Ultrasound of Normal TMJ
40
Nuclear Medicine Bone Scan
(4)
* Imaging technique where bone binds a
radioisotope Tc99
* Gamma camera takes images of where the
radioisotope has collected
* Metabolic activity determines degree of
radioisotope binding
* Binding determines the signal strentgth
41
Nuclear Medicine Bone Scan
Advantages
(1)
1) Radioactive isotope concentrates in areas
of rapid bone turnover and gives positive
response with 10% increase of osteoblastic
activity
42
Nuclear Medicine Bone Scan
Disadvantages
(3)
1) Expensive and invasive
2) Morphologic changes not imaged
3) Findings not specific to any disease process
43
PET CT
(2)
* Combination of PET and CT is referred to as hybrid
or fusion imaging
* Superior to plain nuclear medicine alone
44
PET CT
Useful for:
(3)
* location of a tumor
* followup of chemotherapy or surgery
* staging dementia, evaluate stroke
45
PET - CT FDG Overview
Positron Emission Tomography-
Computed Tomography
(2)
» Fluorine-18 (18F) is a positron-
emitting radioactive isotope that
is used with a glucose analogue
for quantitative imaging i
» Computed tomography (CT) is
fused or co-registered with the
PET scan to aid in interpretation
46
Increased FDG uptake is evident as
increased brightness in left
condyle laterally and superiorly. Comparison of left and right
condyles joints illustrates difference in FDG uptake.
47
PET SCAN
Advantages
(2)
* Allows functional study of a metabolic
process
* Provides a visual image that
corresponds with patient anatomy
48
PET SCAN
Disadvantages
(3)
* Higher dosimetry
* High finances
* Slow imaging; not capable for time
sequences > 30 seconds
