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- 1. Dept. Oral Medicine and Radiology Govt. Dental College Trivandrum Seminar Topic : TMJ IMAGING Presented by, ASWATHY.B Final year part 1 GDC Trivandrum
- 2. Contents Introduction Hard tissue imaging Techniques Soft tissue imaging Techniques Conclusion References
- 3. Introduction A thorough understanding of the anatomy and morphology of the TMJ is essential so that a normal variant is not mistaken for an abnormality. Several variable must be considered when selecting the type of imaging techniques to use, including the specific clinical problem to be addressed, whether the imaging of the hard or soft tissue is desired, the strength and limitations of the modalities being considered, the cost of the examination and the radiation dose. Both joints should be imaged during the examination for comparison.
- 4. TMJ Imaging Types of imaging techniques depends on, Specific clinical problem Need for image of hard or soft tissue Amount of information image Cost Radiation dose TMJ Imaging Hard tissue imaging Soft tissue imaging
- 5. Hard tissue Imaging 1. Tomography conventional computed OPG CBCT 2 Conventional Submentovertex Transcranial Transpharangyeal Transorbital Lateral oblique
- 6. Soft tissue imaging Arthrography MRI Ultrasound Abnormalities in TMJ Imaging In Hard tissue imaging, Bony ankylosis Remodelling Developmental anomalies Neoplasm Trauma or fracture Range of motion
- 7. In soft tissue imaging, Disc position Disc perforation Joint effusion Inflammatory condition Joint space calcification Panoramic imaging The panoramic image is a useful tool for providing a broad overview of the anatomic structures of and around the tmj. It serve as a screening radiograph only. It is used to identify gross osseous changes like, 1. Assymmetry 2. Extensive erosions 3. Tumors 4. Fractures 5. Osteophytes
- 8. Limitations 1. Low quality images 2. Provide thick image layer 3. Oblique and distorted view 4. No information regarding condylar positioning and function 5. Superimposition by skull base and zygomatic arch Plain film imaging modalities The plain film usually consists of combination of following projections and allows visualization in various planes. Transcranial projection Trasnspharyngeal projections Transorbital projections Submentovertex projections
- 9. Transcranial projection It is a view that aids in visualizing the sagittal view of the lateral aspect of condyle and temporal compartment. It is taken in both open and closed mouth position Patient position : sagittal plane is perpendicular to the ground Cassette: parallel to sagittal plane Central ray: point of entry is two and a half inches above external auditory meatus and behind Vertical angulation: 25° Horizontal angulation : 20° Film position : Cassette is placed flat againt ear and centered over tmj of interest Point of exit : Tmj of interest
- 11. Uses For identifying gross osseous changes in lateral aspect of joint Displaced condylar fracture Studying range of motion of tmj Joint space calcification Limitations Super imposition of ipsilateral petrous part of temporal bone Changes in Central and medial surfaces not seen Condylar position difficult to determine especially if individualisation of horizontal angulation is not done for each patient.
- 12. Trasnspharyngeal projections Also known as PARMA Projection or MACQUEEN DELL Technique It provide the sagittal view of medial pole of condyle. It is taken in open mouth position Patient position Sagittal plane : perpendicular to ground Coronal plane : perpendicular to ground Cassatte : parallel to sagittal plane Mouth open position Central ray Entry : sigmoid notch of opposite side Vertical angulation : - 5 °to - 10° Horizontal angulation : 10 °posterior to line following right and left bony meatus Film postion Against patient ear Centered to half inch anterior to external auditory meatus Exit point : coronoid, condyle and zygomatic arch of opposite side below base of skull
- 14. Uses To see the medial aspect of condyle To see gross changes in medial aspect especially erosive changes Limitations Temporal component not imaged well Only open mouth position is possible
- 15. Transorbital projections It is taken in the open or protruded position and depicts the entire medial lateral aspect of condyle in frontal plane. Also called Zimmer Projection Patient position Sagittal plane : perpendicular to ground Right baseline parallel to ground Mouth open position Central ray Vertical angulation : 10° Horizontal angulation : 30° Entry : ipsilateral orbit Exit: ipsilateral condyle Film position Behind patient ‘s head Angle 45 ° to sagittal plane
- 17. Uses Provide anterior view of tmj Mediolateral eminence of articular eminence seen For seeing condylar neck fracture, gross generative changes Limitation Only neck is seen in cases of reduced condylar movement
- 18. Submentovertex projections It provides aview of skull bone and condyle in a horizontal plane Structures seen : symmetrical Projection of petrosa, mastoid process, foramen ovale, spinosum canals, carotid canals, sphenoidal sinuses, mandible, maxillary sinus, nasal septum, odontoid process of atlas etc. Patient position Head: Centre of Cassette Neck and head – tipped as far as possible Mid sagittal plane : perpendicular to plane of film Central ray 90°to film and mid sagittal plane, 90° to imaginary line joining mandibular first molars
- 19. Uses : gives a view of base of skull and condyles, determine the angulations of long axis of the condylar head , evaluating facial assymmetry, condylar displacement.
- 20. Tomography It is a radiographic technique designed to image more clearly objects lying within plane of interest. Image outside the area of interest are blurred out. Types, 1. Conventional tomography 2. Computed tomography 3. Cone beam computed tomography Conventional tomography Also known as body section radiography Film based tomography Equipments X- ray tube Radiographic film
- 21. Procedure X- ray tube and radiographic film are placed on opposite sides of fulcrum, imaginary point located with in the body’s plane of interest ( focal plane). During exposure, tube and film move in opposite direction synchronously about fulcrum which is static. Thus the image of objects with in the focal plane are Clearly formed and those outside are blurred. Advantages Multiple thin image slices are produced which permit visualization of structures free of Superimposition. Disadvantages Images which reduced contrast Uses Provide 3D shape Internal osseous components Extent of ankylosis Neoplasm Imaging complex fractures Complication from implants
- 22. Indications Tomography of sinuses Tomography of mandible Tomography of facial bones to study facial structures For dental implant patients Tomography of tmj in conjunction with arthrography Computed tomography Synonyms : computed axial tomography, computerized axial transverse scanning Sectional images are produced 1. Axial 2. Coronal 3. saggital
- 23. Equipments Radiographic tube emits fan shaped x- ray beam Scintillation detector or ionization chambers Here both move in a synchronized manner around the patient. Indication Investigation of tmj Cone beam computed tomography Principle : cone shaped x- ray source CBCT examination is usually acquired with the patient in the closed mouth position with teeth in maximum intercuspation. CBCT system allows low resolution image acquisition to be done in open mouth or other position to evaluate range of motion
- 24. Indications Determining the presnce and extent of ankylosis Neoplasm Fractures Evaluating complications from the use of polytetrafluoroethylene or silicosheet implants and identifying heterotropic bone growth. Soft tissue imaging Indication Disc position and morphology Image abnormalities in muscle or surrounding tissues Abnoramalities of soft tissues Disc perforation Disc position Fibous ankylosis Joint effusion Infkammatory condition Joint space calcification
- 25. Magnetic Resonance Imaging MRI uses static and gradient magnetic fields and non ionizing electromagnetic radiation in the form of radiofrequency pulses to produce tomographic images Principle Transfer energy to spinning hydrogen protons Resonance frequency for protons lies with in the radiofrequency band of electro magnetic spectrum. The examination may be performed with the use of T1 weighted, proton density or T2 weighted pulse sequence depending on the type of information required. Proton density images are slightly superior to T1 weighted images in demonstrating osseous and discal tissues, whereas T2 weighted images demonstrate inflammation and joint effusion.
- 26. Indication For tmj marrow changes and soft tissue components Contraindications Patient who have a pacemaker or some other implanted devices, intracranial vascular clip, metal particles in vital Structures. Patient with claustrophobia Arthrography It is a technique in which an indirect image of the disk is obtained by injecting a radio opaque contrast agent into the joint spaces under fluoroscopic guidence. Indications Position and function of disk History of persistent locking Disk pain and dysfunction
- 27. Disk perforation Joint dynamics Disk displacement Contra Indications Infections in preauricular region Patient allergic to contrast media Patient withbleeding disorders and on anticoagulant therapy. Complications Vascular injury Extravasation of irrigation fluid into surrounding tissues Infections Nerve injury
- 28. Arthroscopy This procedure helps in the direct visualization of internal joints Last line of investigation Procedure is similar to arthrography Used for evaluating articular cavity condition Advantages Safe procedure Direct visualization Minimal post operative complications Color change is clearly seen
- 29. Ultrasonography Used for the study of tissues of human body with utilizationof reflection of high frequency sound waves ranging between 1-20MHz Tranducer generate high frequency Ultrasound waves, most important component is thin piezoelectric crystals At tissue interface, some waves are reflected and some are absorbed Clinical application TMJ disorder Myofacial pain dysfunction syndrome To assess the correct location of joint spaces As an alternative to MRI contraindicated patients
- 30. Conclusion There are many lesser known techniques in maxillofacial imaging which can be used as a powerful tool for demonstrating a large variety of craniofacial structures. Although new paradigms for x- ray imaging techniques have emerged, they may not be economic and readily feasible to be used in many health centers. In such cases, some of these techniques can still be used as a standard procedure for demonstrating various craniofacial structures.
- 31. References 1. White and Pharaoh’s oral radiology, Sanjay. M. Mallya, Ernest W. N Lam 2. Text book of oral Medicine and Oral Diagnosis and Oral Radiology – Ravikiran Ongole, Praveen B. N 3. Textbook of Oral Medicine and Oral Radiology by Peeyush Shivhare.