Transcript TEMPEROMANDIBULAR JOINT IMAGING

DIAGNOSTIC IMAGING OF
TEMPEROMANDIBULAR JOINT
Introduction
 The temporomandibular joint, or TMJ, is the
articulation between the condyle of the
mandible and the squamous portion of the
temporal bone.
 The condyle is elliptically shaped with its long
axis oriented mediolaterally.
 The articular surface of the temporal bone is
composed of the concave articular fossa and
the convex articular eminence.
Normal Anatomy
 Osseous structures
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Glenoid fossa
Articular eminence
Mandibular condyle
Post-glenoid tubercle
Normal Anatomy
 Soft tissue components
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Disk
Joint capsule
Synovia
Lateral ligament
 Upper and lower joint spaces
Normal Disk Position
When the mouth opens, two distinct motions occur at the joint. The
first motion is rotation around a horizontal axis through the condylar
heads. The second motion is translation. The condyle and meniscus
move together anteriorly beneath the articular eminence. In the closed
mouth position, the thick posterior band of the meniscus lies
immediately above the condyle. As the condyle translates forward, the
thinner intermediate zone of the meniscus becomes the articulating
surface between the condyle and the articular eminence. When the
mouth is fully open, the condyle may lie beneath the anterior band of
the meniscus
Imaging
 The decision to image is made after evaluation
of patient history, clinical findings, and in some
cases response to conservative treatment
 Hard tissue imaging
 OPG
 Plain films- TMJ views, SMV and conventional
tomography
 Specialized- CT, Nuclear medicine
 Soft tissue imaging
 Arthrography
 MRI
Plain Films in TMJ
Disorders
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Transcranial
Transorbital
Transpharyngeal
Others
 Submentovertex
 Reverse Towne’s
 Lateral oblique
TRANSCRANIAL
PROJECTION:(Lindblom technique)
 Lateral aspect of TMJ well visualized.
 Central / medial part of TMJ not clearly seen- since xray beam is not target to these articular surfaces.
 This disadvantage partly compensated because of
most of early osseous changes occurs laterally in joint.
 TECHNIQUE AND POSITIONING:
 MAIN INDICATIONS:
 TMJ pain dysfunction syndrome and internal derangement of
joint producing pain, clicking, limitation in opening.
 To investigate size and position of disc this can only be
inferred indirectly from relative position of bony elements of
joints.
 To investigate range of movement in joint.
TMJ Transcranial
 DIAGNOSTIC INFORMATION:
 Information provided by closed view includes:
 This provides indirect information about position and shape of
disc. (Joint space radiologically refers to radiolucent zone
between condylar head and glenoid fossa, which includes disc
and upper /lower anatomical joint spaces.)
 Position of head of condyle within fossa Shape and condition of glenoid fossa a articular eminence (on
lateral aspect only).
 Shape of head of condyle and condition of articular surface.
(On lateral aspect only)
 A comparison of both sides.
 INFORMATION PROVIDED BY OPEN VIEW
INCLUDES:
 Range and type of movement of condyle.
 Comparison of degree of movement on both sides.
TRANS PHARYNGEAL:
(Infra cranial TMJ projection, Parma,
Mc Queen projection)
 MAIN INDICATIONS:
 TMJ pain dysfunction syndrome.
 To investigate presence of joint disease particularly
Osteoarthritis & Rheumatoid arthritis.
 To investigate pathological conditions affecting
condylar head, including cysts or tumors.
 fracture of neck and head of condyle.
 Sup surface of condyle visualized.
TRANS ORBITAL
PROJECTION: (ZIMMER)
 TECHNIQUE AND POSITIONING:
 Conventional frontal TMJ projection is most routinely
successful in delineating joint with minimal super
imposition is transorbital (ZIMMER) projection, also
called Transmaxillary Projection.
 Advantage- Lack of major superimposition over most of
condylar process. Productions of relatively true
“enface” frontal projection of condyle (directing central
ray perpendicular to long axis of condyle) and simplicity
with which it is made.
 Patient positioning-
TMJ- Transorbital
Panoramic Imaging
 Shows significant erosion, sclerosis, or
osteophyte
 Probable fracture diagnosis
 Little info on articular eminence or fossa
 Good initial examination
 Some pan machines have TMJ programs
 MAIN INDICATIONS:
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TMJ pain dysfunction syndrome.
To investigate disease within joint.
To investigate pathological condition affecting condylar head.
Fracture of condylar head or neck.
Condylar hypo/hyperplasia.
 DIAGNOSTIC INFORMATION:
 It gives information of shape of condylar heads and condition
of articular surfaces from lateral aspect.
 Direct comparison of both condylar heads.
 Some panaromic machines can give closed and open view of
condyle is not of information.
 Two views of condyle at maximum opening will reflect
maximum translation from initial closed position, it will
maximize information and minimize patient absorbed x-ray
dose.
Condylar hyperplasia: note elongated
right condyle
Condylar hyperplasia: note relatively
elongated left mandibular condyle.
Mandibular condylar hypoplasia: The left
condyle is smaller and altered in shape
in comparison with the right.
R
Osseous ankylosis (arrowheads) between coronoid
process and zygomatic arch. Metallic sutures are
from a previous trauma-related operation.
Others
 SMV
 Reverse towne’s
 Lateral oblique
SUBMENTOVERTEX
PROJECTION
 Projection show base of the skull,
sphenoidal sinuses and facial skeleton
from below
 This view helps ruling out TMJ erosion
from nasopaharygeal carcinoma
extending to base of skull. Also be used
to define angulations of condyle in
transverse plane of skull.
REVERSE TOWNE’S
 MAIN INDICATIONS:
 To investigate articular surface of condyle and
disease within joint.
 Fracture of condylar head and neck (especially
medially displaced fracture of condyle)
 Condylar hypo/hyperplasia.
 TECHNIQUE:
 USES To know the Shape of condylar heads and condition
of articular surface from posterior aspect.
 A direct comparison of both condyles.
Lateral Oblique Projection
Tomography
 MAIN INDICATIONS:
 Estimation of joint space, examination of condylar surface from
medical to lateral pole for arthritic changes, visualization of
condylar translation, visualization of articular eminence
changes.
 It helps in assessment of whole of joint to determine presence
and site of any bone disease or abnormality.
 To investigate condyle and articular fossa, when patient
unable to open mouth.
 Assessment of fracture in the articular fossa and intra capsular
space.
 Tomography in Coronal Plane provides information about
medial and lateral poles of condyle, which is not adequately
depicted on sagittal tomograms.
 Osseous structures
 Condylar position
 Used along with arthrography
 Disadvantage of Tomography is large
irradition dose delivered to lens of eye.
 Types Linear tomogram
 Multidirectional Hypocycolloidal
tomogram
 Multi-Computer Controlled Spiral tomogram
 DIAGNOSTIC INFORMATION: to know
 Size of joint space.
 Position of head of condyle within fossa.
 Shape of head of condition of articular surface including medial
and lateral aspects.
 Shape and condition of articular fossa and eminence.
 Information on all aspects of joint.
 Position and orientation of fracture fragment.
 Body section tomography provides most definitive radiologic
information about TMJ.
 Complex motion tomography (hypocycloidal) /spiral motion) is
superior to transcranial radiography for demonstrating changes
on articulating surface and position of condyle within
mandibular fossa.
 An initial SMV projection required to measure angles of
each condyle within information patient head may be
oriented correctly for performing Tomography
examination
 Tomographic section of TMJ made in 2
orientations with respect to joint
 With head positioned so that section is at
right angle to long axis of condyle (the
lateral tomographic section.)
 Often with section parallel to long axis of
condyle (frontal tomographic section)
 A proper tomographic examination is
comprised of from 4-7section at 2-3 mm
intervals.
Tube and film move
in opposite direction,
and rotate about a
fulcrum
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Focal plain
The level of the
fulcrum is the focal
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plain
TMJ - Tomograms
Tomograms
TMJ osteoarthrosis
Conventional tomogram: Joint “space” is thinned
because of loss of articular cartilage. Anterior
osteophyte is composed of dense cortical bone and
articular eminence (E) is eburnated.
CT Scan
 CT permits the imaging of thin slices of tissues in a
wide variety of planes, and provide axial, coronal and
sagittal plane
 Slices thickness-10mm-body and brain
 5mm- H&N
 3D recon- 1-1.5mm
 Images viewed- bone windowing and soft tissue
windowing
 Scan images are composed of picture elements(pixels)
 Hounsfield scale-’0’HU(water), -1000HU(air),
 TMJ-sagittal projection-most suitable
 Radiation dose- less than that of tomography or
arthrotomography
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Sagittal
Coronal
Axial
Indications Not for soft tissue changes
 Evaluation of trauma and tumors
 Perforation of alloplastic grafts into cranial
fossa
 Volume averaging
 Accuracy and limitations
Normal
Flattening
MRI
 Uses electrical and magnetic fields and
radiofrequency
 No assoc radiologic risk and non-invasive
 Soft tissues are imaged directly
 C/I: Claustrophobia pts not tolerated, pts
with metallic vascular clips, metallic
implants and pacemakers
 Disk location and displacement (~ 95%
accuracy)
 Osseous details poor
 Soft tissue changes
 Fluid or joint effusion
 Protocol dependant
MRI Parameters
TR
TE
Term
Effect
Short
Short
T1 Anatomy –excellent
Disk -low intensity
Long
Long
T2 Poor anatomy
Joint effusion – high intensity
Relative Brightness of
Tissues
Fat
Marrow
Brain
Muscle
Body fluid
TMJ disk
Cortical bone
Air
white
gray
black
Normal T1-weighted
MRI of TMJ
(TR450,TE20)
Closed mouth
Condyle (C); Glenoid fossa (F); Articular eminence (E);
Anterior band (A); Posterior band (P).
Normal T1-weighted
MRI of TMJ
(TR450,TE20)
Open mouth
Condyle (C); Glenoid fossa (F); Articular eminence (E);
Anterior band (A); Posterior band (P). Note classic
“bowtie” appearance of disk.
Arthrography
 Temporuniandibular arthrography
utilizes the injection of radiopaque
material into on or both of the joint
compartments to enhance the contrast
between the disc and spaces.
 The shape and position of the disc are
then inferred from the shapes of
opacities above and below it.
 Single and double contrast
 Indication
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Internal derangements
Disk perforation
As a therapy?
Arthrocentesis
 Contraindication
 Infection
 Contrast sensitivity
Atthrographic evidence of perforation is seen
fluoroscopically during injection of the contrast
medium into the lower joint compartment. The
radiopaque material can be seen flowing into the
upper joint space, and injection of this compartment
becomes unnecessary.
Arthrography: Technique
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Clinical exam and history
Informed consent
Asepsis and anesthesia
Contrast agents
Injecting the contrast material under
fluoroscope
 Translation of condyle
 A 25 or 23 gauge needle is placed into the inferior joint
space immediately posterior to the condyle. Small
amounts of iodinated contrast are injected under
fluoroscopy. The contrast tracks along the posterior,
superior and anterior portions of the condyle. The
anterior collection of contrast, called the anterior
recess, normally has a smooth, tear-drop shape.
 If the meniscus is perforated, contrast flows into both
the superior and inferior joint recesses. However, the
arthrographic needle can inadvertently puncture the
meniscus and cause iatrogenic filling of both joint
spaces.
 As the condyle translates anteriorly, the contrast
usually empties from the anterior recess and flows
posteriorly.
 When the meniscus is anteriorly displaced, the anterior
recess becomes abnormally elongated. Often the
displaced meniscus is deformed or buckled, which
results in a mass effect against the contrast in the
anterior recess. As the condyle translates anteriorly,
the mass effect against the anterior recess often
increases. When the meniscus reduces, the anterior
recess returns to a normal appearance.
 If the meniscus does not reduce, the anterior recess
remains deformed in the fully open mouth position.
 R/Gs
 POST-OP INST
Scout Tomogram
 Osseous structures
 Disk space
 Sclerotic changes
Opacification of Lower
Space
Open Position
 Translation of
condyle
 Reduction of disk
Protruded Position
Closed mouth
Open mouth
Normal
TMJ
arthrogram
Intermediate zone (Z) lies in narrowest part of joint
condyle (C) and articular eminence (E). The anterior (A) and posterior (P) bands
occupy the wider part of
the joint. Glenoid fossa (F).
Usually, in an arthrogram of a normal TMJ, little contrast medium appears
anterior to the condyle in the closed mouth position and this volume is
further reduced in the opened mouth position. Throughout the range of
motion, the posterior band remains behind the condyle, the anterior band
remians ahead, and the thin intermediate zone remains between the two
functional surfaces.