Diagnostic Imaging of the Temporomandibular Joint Class PDF

Diagnostic Imaging Of TMJ Dr Arishiya Thapasum 11/17/2021 Objective of the lecture  To help supplement clinical examination, a thorough knowledge about the radiographic anatomy and morphology of the temparomandibular joint is essential.  To analyze the various hard tissue and soft tissue imag...

Diagnostic Imaging Of TMJ Dr Arishiya Thapasum 11/17/2021 Objective of the lecture  To help supplement clinical examination, a thorough knowledge about the radiographic anatomy and morphology of the temparomandibular joint is essential.  To analyze the various hard tissue and soft tissue imaging modalities of the temparomandibular joint by understanding their uses, limitations, advantages and disadvantages and thereby help select appropriate imaging technique.  To know the various radiographic abnormalities of the temparomandibular joint. 11/17/2021 Content of the lecture  Introduction  Radiographic anatomy  Hard tissue imaging  Soft tissue imaging  Radiographic abnormalities of TMJ  Soft tissue abnormalities of TMJ  Remodeling and arthritic conditions  Trauma and fracture of the TMJ  Trauma to the developing condyle  Tumors affecting the TMJ (benign and malignant) 11/17/2021 11/17/2021 Posterior band of articular disc Anterior band of articular disc Mandibular condyle (head) Lateral pterygoid muscle raphe Lower head of lateral pterygoid muscle Posterior disc attachment 11/17/2021 Normal Anatomy Mandibular condyle (head) Glenoid fossa Articular tubercle (eminence) 11/17/2021 Mandibular condyle (head) Articular disc 11/17/2021  CONDYLE: - Shape of condyle varies considerably - Superior aspect maybe flattened, rounded or markedly convex - Mediolateral contour is usually slightly convex - Variations in shape may cause difficulty with radiographic interpretation - Extreme aspects of the condyle are the medial pole and lateral pole 11/17/2021  MANDIBULAR FOSSA: Composed of the glenoid fossa and articular eminence.  INTERARTICULAR DISK: - Between condylar head and mandibular fossa - Biconcave shape 11/17/2021 Transcranial projection 11/17/2021 Transpharyngeal projection 11/17/2021 Transorbital projection 11/17/2021 Arthrography SMV Tomogram MRI 11/17/2021 Disorders of the temporomandibular joint are abnormalities that interfere with the normal form or function of the joint 11/17/2021 1- Developmental Abnormalities 2- Soft Tissue Abnormalities 11/17/2021  Developmental Abnormalities: 1- Condylar Hyperplasia 2- Condylar Hypoplasia 3- Juvenile Arthrosis 4- Coronoid Hyperplasia 5- Bifid Condyle 11/17/2021 Condylar Hyperplasia - Enlargement and deformity of the condylar head - Secondary effect on the mandibular fossa as it remodels to accommodate the abnormal condyle Etiology: Trauma, infection, hereditary  More common in males  Self limiting  Mandibular asymmetry  Chin deviated to the opposite side 11/17/2021  Radiographic Features:  OPG, CT, Scintigraphy  Condylar neck, glenoid fossa, ramus and mandibular body on the affected side also may be enlarged, resulting in a characteristic depression of the inferior mandibular border  D/D: - Osteochondroma - Condylar osteoma or osteophyte that occurs in chronic degenerative joint disease 11/17/2021 Condylar Hypoplasia  The condyle is small, but condylar morphology is normal  The mandible deviates to the same side  Unilateral or bilateral 11/17/2021 11/17/2021  Radiographic Features:  The condylar neck and coronoid process usually are very slender and are shortened or elongated in some cases  The ramus and mandibular body on the affected side may also be small, resulting in a mandibular asymmetry and occasional dental crowding, depending on the severity of mandibular underdevelopment  D/D: Juvenile rheumatoid arthritis and arthritic conditions 11/17/2021 Juvenile Arthrosis  Manifests as hypoplasia and characteristic morphologic abnormalities  May be a form of condylar hypoplasia  It affects children and adolescents  More common in females  Incidental finding in a panoramic projection 11/17/2021  Radiographic appearance:  Condylar head develops a characteristic “toadstool” appearance  Condylar neck is shortened or even absent in some cases  D/D: developmental hypoplasia rheumatoid arthritis 11/17/2021 Coronoid Hyperplasia  - acquired or developmental  - elongation of the coronoid process  - developmental -> bilateral  acquired -> uni or bilateral  - inability to open mouth  - painless 11/17/2021 Radiographic features:  Best seen in panoramic, Waters, and lateral tomographic views and on CT scans  TMJs usually appear normal D/D: Unilateral cases should be differentiated from a tumor of the coronoid process (osteochondroma or osteoma)  Unlike coronoid hyperplasia, tumors have an irregular shape 11/17/2021  5- Bifid Condyle:  Vertical depression, notch, or deep cleft in the center of the condylar head  Rare, often unilateral  Incidental finding  Some patients may have sings of TMDs (noises + pain)  Radiographic Features:  Depression on the superior condylar surface giving a heart shape 11/17/2021  D/D: Vertical fracture through the condylar head  Treatment: Not indicated unless pain or functional impairment is present 11/17/2021 Soft Tissue Abnormalities  Internal Derangements - abnormality in the articular disc and may interfere with normal function  - Cause is unknown  - Internal derangements can be diagnosed by MRI  Clinical Features:  - found in both symptomatic and healthy patients  - symptomatic patients may have a decreased range of mandibular motion  -displacements may be unilateral or bilateral 11/17/2021 11/17/2021 Complete anterior disc displacement medial section 11/17/2021 Autopsy Open-mouth MRI Medial disc displacement coronal MRI 11/17/2021 Oblique coronal MRI  Radiographic Features:  - MRI is the technique of choice  Disc Displacement:  - Anterior displacement is most common  - The articular disc is located anterior to the condylar head  Disk reduction and nonreduction:  - reduction is when an anteriorly displaced disk may reduce to a normal relationship with the condylar head during any part of the mouth opening movement  - non-reduction is when the disk remains anteriorly displaced and will undergo permanent deformation. 11/17/2021  Perforation and Deformities:  - perforations between the superior and inferior joint spaces most commonly occur in the retrodiscal tissue, just behind the posterior band of the disk  - Not reliably detected with MRI, arthroscopy is the imaging method of choice  Fibrous Adhesions and Effusion:  - Fibrous adhesions are masses of fibrous or scarred tissue that form in the joint space, particularly after TMJ surgery  - Joint Effusion means fluid in the joint and is considered to be and early change that may precede degenerative joint disease  - Both can be detected by MRI 11/17/2021 Remodeling and Arthritic conditions Remodeling:  - Adaptive response of cartilage and osseous tissue to forces applied to the joint that maybe excessive, resulting in alteration of the shape of the condyle and articular eminence  - no destruction or degeneration of articular soft tissue occurs  - occurs throughout adult life  - considered abnormal only if it is accompanied by clinical signs and symptoms of pain or dysfunction 11/17/2021  - Radiographic Features:  - flattening  - cortical thickening of articulating surfaces  - subchondral sclerosis  -D/D: early degenerative joint disease 11/17/2021 Degenerative joint disease (osteoarthritis)  Non-inflammatory disorder  can occur at any age (incidence increases with age) with female predominance  tenderness on palpation and movement, joint noises, (crepitus), limited range of motion, and muscle spasm  Radiographic features:  more accurately seen in CT but gross osseous changes maybe evident in MRI studies  At the maximum intercuspation joint space may be narrow or absent  Loss of articular cartilage or erosions of the articulating surfaces of the condyle or temporal component are characteristics of this disease, subchondral sclerosis, osteophyte, Ely cyst, joint mice are also seen 11/17/2021 Flattened temporal component Ely’s cyst 11/17/2021 Joint mice Advanced osteoarthritis and anterior disc displacement, with joint effusion 11/17/2021  D/D:  - Erosive appearance  inflammatory arthritides (rheumatoid arthritis)  - Proliferative appearance with extensive osteophyte formation  benign tumor  osteoma or osteochondroma 11/17/2021 Rheumatoid Arthritis  - Synovial membrane inflammation  - Patients with TMJ involvement complain of swelling, pain, tenderness, stiffness on opening, limited range or motion, and crepitus  - Radiographic Features:  - Osteopenia (decreased density) of the condyle and temporal component  - erosion of anterior and posterior condylar surfaces  if erosion is severe  condylar head is destroyed 11/17/2021 Rheumatoid arthritis. A MRI shows completely destroyed disc, replaced by fibrous or vascular pannus and cortical punched-out erosion (arrow) with sclerosis in condyle. 11/17/2021 Juvenile Arthritis  - Inflammatory disease that is characterized by chronic, intermittent synovial inflammation  - results in: synovial hypertrophy, joint effusion, and swollen, painful joints  -pain and tenderness of affected joint or joints  - can be asymptomatic  - unilateral is common  - facial appearance known as “bird face”  - possible mandibular asymmetry if one side is more severely affected 11/17/2021 11/17/2021  Radiographic features:  - Osteopenia (decreased density) may be only an initial radiographic finding  - Impaired mandibular growth  - Severe cases: only pencil shaped small condyle remains  - Abnormal disk shape is often observed in patients with TMJ involvement 11/17/2021 Septic Arthritis Infection and inflammation of a joint that can result in joint destruction - Affects any age, no sex predilection ,occurs unilaterally - Redness and swelling over joint - Severe pain on opening ,Inability to occlude the teeth, trismus - Fever and malaise, large, tender cervical lymph nodes 11/17/2021  Radiographic Features: - No radiographic signs may be present in early stages of the disease - Space between the condyle and the roof of the mandibular fossa may be widened because of inflammatory exudate in the joint spaces - Osteopenic (radiolucent) changes of the joint components and mandibular ramus may be evident (7-10 days after onset of clinical symptoms) - Osseous ankylosis may occur after infection subsides 11/17/2021  D/D: radiographic changes caused by septic arthritis may mimic those of severe DJD or RA 11/17/2021 Articular Loose Bodies - Radiopacities of varying origin located in the joint synovium, within the capsule in the joint spaces, or outside in soft tissue 1- Synovial Chondromatosis: - characterized by metaplastic formation of multiple cartilaginous and osteocartilaginous nodules within connective tissue of the synovial membrane of joint , some of these nodules may detach and form loose bodies in the joint space, - Asymptomatic - May complain of preauricular swelling, pain, and decreased range of motion - Some patients have crepitus or other joint noises 11/17/2021  Radiographic Features: - Osseous components may appear normal or may exhibit osseous changes similar to those in DJD  The joint space may be widened, a radiopaque mass or several radiopaque loose bodies may be seen surrounding the condylar head  CT imaging can identify the location of the calcifications. * D/D: DJD with joint mice or chondrosarcoma or osteosarcoma 11/17/2021 11/17/2021 2- Chondrocalcinosis: - Characterized by acute or chronic synovitis and precipitation of calcium pyrophosphate dihydrate crystals in the joint space - Most commonly affected joints are knee, wrist, shoulder, and elbow - TMJ involvement uncommon - Unilaterally and more common in males - Asymptomatic or complaints of pain and joint swellings 11/17/2021  Radiographic Features:  the radiopacities within the joint space are finer and have a more even distribution than in osteochondromatosis - Bone erosions and severe increase in condylar bone density - Erosions of the glenoid fossa may be present (detected with CT) * D/D: DJD with joint mice or chondrosarcoma or osteosarcoma 11/17/2021 Trauma 1- Effusion: - Influx of fluid into the joint as a result of trauma (hemorrhage or inflammation) - Swelling over affected joint - Pain in TMJ, preauricular region, and limited range of motion 11/17/2021  Radiographic Features: - Commonly seen in conjunction with internal derangements - Joint space is widened * D/D: septic arthritis * Treatment: - Anti-inflammatory drugs - Surgical drainage 11/17/2021 Dislocation - Abnormal positioning of the condyle out of the mandibular fossa but within the joint capsule - Unable to close mandible to maximal intercuspation * Radiographic Features: - In bilateral cases, both condyles are located anterior and superior to summits of articular eminence * Treatment: - Manual manipulation to reduce the dislocation - Surgery in the case of fracture dislocation 11/17/2021 Fracture - Usually occur at condylar neck and often are accompanied by dislocation of the condylar head - Unilateral fractures more common - May be accompanied by parasymphyseal or mandibular body fracture on contralateral side - Swelling over TMJ - Limited range of motion 11/17/2021  Radiographic features: - Radiolucent line limited to the outline of the neck is visible - If bone fragments overlap, an area of increase in radiopacity may be seen  The outer cortical boundary may have an irregular outline or a step defect.  Multiple right-angle radiographic projections from the lateral, frontal, and basilar aspects are required to detect a fracture * Treatment: Reduced surgically 11/17/2021 Neonatal Fracture - Use of forceps during delivery of neonates may result in fracture and displacement of the rudimentary condyle - Severe mandibular hypoplasia •D/D: Developmental hypoplasia * Treatment: Combination of orthodontic and orthognathic surgery 11/17/2021 Ankylosis - Condition in which condylar movement is limited by a mechanical problem in the joint or by a cause not related to joint components - Restricted or limited jaw opening * Radiographic Features: - In fibrous ankylosis articulating surfaces are usually irregular because of erosions and joint space is narrow - In bony ankylosis joint space may be partly or completely obliterated by the osseous bridge - Coronal CT images are the best to evaluate ankylosis * D/D: Condylar Tumor 11/17/2021 Tumors - Intrinsic or extrinsic - Intrinsic develop in condyle, temporal bone or coronoid process - Extrinsic tumor may affect the morphology, structure and function of the joint without invading the joint itself 11/17/2021 Benign Tumors - Osteoma, osteochondroma, Langerhans histocytosis and osteoblastomas - Chondroblastomas, fibromyxomas, benign giant cell lesions and aneurysmal bone cysts also occur - Benign tumors and cysts of the mandible may involve the entire ramus and condyle - Grow slowly, TMJ swelling, Pain and decrease in range of motion - Tumors of coronoid process are painless but may complain of progressive limitation of motion 11/17/2021 Axial bone algorithm. CT image of an osteochondroma extending from the anterior surface of the left condylar head (arrow) Osteomas 11/17/2021 * Radiographic Features: - Condylar tumors  condylar enlargement (radiolucent or radiopaque) with irregular outline - Osteoma and osteochondroma appear as abnormal, pedunculated mass attached to the condyle * D/D: condylar hyperplasia because of condylar enlargement although it might be irregular in appearance * Treatment: Surgical excision of tumor and occasionally excision of condylar head or coronoid process 11/17/2021 Malignant Tumors A- Primary (rare): - Intrinsic - Extrinsic Intrinsic: Chondrosarcoma Osteogenic sarcoma Synovial sarcoma Fibrosarcoma Extrinsic: Direct extension of adjacent parotid salivary gland malignancies  The metastatic lesions include neoplasms originating in the breast, kidney, lung, colon, prostate, and thyroid gland. 11/17/2021 Chondrosarcoma chondrosarcoma (CT axial section bone algorithm) radiolucent destructive lesion present in the left condylar head and faint radiopacities (soft tissue calcifications) are visible anterior to the condylar head (arrows) 11/17/2021 Metastasis from thyroid Axial soft tissue algorithm CT image of a metastatic lesion from a carcinoma of the thyroid gland that has destroyed all of the left mandibular condyle Metastatic - May be asymptomatic or patients may have symptoms of TMJ dysfunction (pain, limited mandibular opening, mandibular deviation and swelling) * Radiographic Features: - Variant degree of bone destruction with ill defined, irregular margins - CT modality of choice - MRI useful for displaying extent of involvement into surrounding tissues * D/D: Osseous destruction of bone seen in severe DJD * Treatment: - Wide surgical removal of tumor - May include radiotherapy and chemotherapy 11/17/2021 Thank you 11/17/2021 References  Oral radiology, Principles and interpretation, White and Pharoah 11/17/2021