CT Temporomandibularjoints.pptx

Temporomandibular joints, computed tomography TM joints, inner ear, ossicles, parts of ossicles, parameters, planning, reformation techniques , few cases to discuss, radiation dose post processing techniques. virtual labyrinthscopy.

1. CT Temporomandibular Joints PRESENTOR :VANI PUSHPA M Sc. RIT Final semester 210513027 MENTOR: ARSHAD ALAM KHAN Assistant Professor Radio-Imaging Technology

2. AIMS: IMPORTANT AND RELEVANT ANATOMY INDICATION MODALITY IMPORTANCE PARAMETERS AND PLANNING REFORMATION AND POST-PROCESSING IMAGE QUALITY RADIATION DOSE FEW CASES VIDEOS REGADNING PLANING AND FILIMING

3. Anatomy: The main functions of TM JOINTS are mastication and speech. The temporomandibular joint (TMJ) is a complex synovial articulation between the mandibular condyle and the temporal bone's glenoid fossa and articular eminence. An intra-articular disc divides the joint into superior and inferior compartments which is fibro cartilaginous biconcave disc The TMJ is normally subject to high biomechanical load from mastication and is unique in that movement of one joint always results in movement of the contralateral side as they are connected by the horseshoe-shaped mandible.

4. Only mobile joint of skull formed between head of mandible and articular fossa of temporal bone.

5. Temporal bone comprises of four osseous parts namely Petro mastoid Squamous Tympanic Styloid

6. Auditory apparatus External ear Ear Pinna External auditory canal Tympanic membrane Middle ear Malleus Incus Stapes Inner ear Cochlea Semicircular canals

7. Modalities importance : U ltrasound could be used to screen for the presence of effusions in patients with TMD. Ultrasound-guided injection of corticosteroids into the inferior joint space can be used for the treatment of pain due to TMD MRI is an optimal imaging technique for evaluating excellent soft-tissue, cortical, and bone marrow evaluation. MDCT provides excellent bone detail and multiplanar two-dimensional (2D) and three-dimensional (3D) reconstructions of the TMJ, M axillofacial region , A djacent skull base , Ossicles Road map for the surgeon Dense cortical bone and contrast with air B ut no soft-tissue information

8. Indications for B one Inner ear Temporomandibular disorder (TMD) disorder of the muscles of mastication D ental treatment or trauma Fractures A palpable mass Ankylosis (fusion of bones) Otosclerosis Imbalance D ischarge Otitis media (infection of the middle ear) Cholesteatoma (noncancerous growth) Inflammatory disease Pre and post-operative Follow up Prior to the cochlear implant metastasis

9. Contraindications: P regnancy due to the teratogenic effect of X-rays on the fetus and children under 14 years of age due to the possible negative effect of X-rays on the growing body Relative contraindications Obesity  (weight more than 180 kg), M ental disorders 

10. Protocol: HRCT Patient position: Supine with head first with arms beside the trunk Topogram: Lateral, 256mm Mode of scanning: Helical Scan Orientation: Craniocaudal Starting location : Cranial limit of the petrous bone End Location : proximal- ramus level Gantry tilt: Nil FOV- Just fitting the temporal and mandibular joint

11. Slice thickness: 1mm Slice interval: 0.25-0.5mm kV/mA: 120/140 Slice thickness for Reformation: 0.25- 1mm Reconstruction Algorithm : Ultra Sharp 3D Reformation – MPR, VR, Navigation technique Multidetector (64-256 sections) CT acquisitions in the closed- and open-mouth positions from above the TMJ to the mid-ramus level, 140kV Open-mouth scans can also be performed to assess condylar mobility

12. The mandibular condyle is centered on the glenoid fossa when the mouth is closed. When the mouth is open, the condyle moves anteriorly under the center of the articular eminence. 

13. Image Quality : Symmetric position with the orbital plates overlapping with each other. Absences of the motion artifacts Optimal delineation of the ossicular chain, facial nerve canal and tympanic cavity. 3D reconstructions are prepared for the planning of cochlear implant surgery MPR is prepared in the oblique coronal and sagittal plane using bone and soft-tissue algorithms

14. Post-processing images : Poschl projection images : In a plane perpendicular to the long axis of the petrous bone show the normal anatomy of the temporal bone from anteromedial to posterolateral Stenvers Projection CT images : In a plane parallel to the long axis of the petrous bone show the normal anatomy of the temporal bone from oblique anterior to oblique posterior LSCC = lateral semicircular canal PSCC = posterior semicircular canal SSCC = superior semicircular canal Nerves

15. 3D VR IMAGES S patial orientation of various parts of the temporal bone 3D reconstruction is based on the data from spiral HRCT using special software using segmentation, volume rendering, and surface rendering algorithm on a CT workstation.

16. Virtual labyrinthscopy Virtual labyrinthscopy of the labyrinth by using volume rendering and navigation technique. Owing to the tiny and complex structures of the inner ear and convenient analysis require high-quality 3d representation and real-time manipulation of viewing direction. These features are provided by interactive direct volume rendering and navigation techniques.

17. MALLEUS AND INCUS FROM SUPERIOR TO INFERIOR VIEW LENTICULAR PROCESS AND LONG PROCESS OF INCUS.MANUBRIUM, LATERAL PROCESS, AND NECK OF MALLEUS RIDGES SEEN IN THE BONY LABYRINTH USING NAVIGATION TECHNIQUE.INSIDES THE COCHLEA.

18. Radiation dose The effective dose for a typical CT exam of the temporal bone is 1 m S v

19. Temporomandibular joint fracture. Axial image showing a severely displaced condylar neck fracture.

20. Displaced right temporomandibular joint compared to the intact left TMJ.  A B

21. zygomaticomaxillary complex (ZMC) fracture

22. L esion of the EAC

23. REFFERENCE: https://doi.org/10.1016/j.crad.2020.06.020 CT Temporal Bone - Indications, Preparation, Interpretation (medic-journal.com) CT AND MRI PROTOCOL BY SUMEET BHARGAVA, SATISH K BHARGAVA CT Temporal Bone Made Easy (Part 1) - Step by Step Approach - Bing video CT Scan of temporal bone technic - Bing video