Table 2 CBCT imaging features for scoring of temporomandibular joint deformity in juvenile idiopathic arthritis

Overall impression of TMJ deformity

0 = normal

1 = mild

2 = moderate/severe

Flattening of the articular eminence and glenoid fossa^a

A change from the expected s-shaped appearance

0 = absent; i.e. s-shaped

1 = mild to moderate widening or flattening

2 = severely flattened fossa/eminence

Surface irregularity of the articular eminence and glenoid fossa^b

Irregular change(s) of surface shape, for example depression. More distinct and sharply demarcated than ‘flattening’. May be continuous or discontinuous

0 = absent

1 = mild (involving only part of the articular surface, including multiple depressions/lesions)

2 = moderate/severe (involving the entire articular surface, or presence of deep brakes in the subchondral bone seen in two planes

Continuity of the articular eminence and glenoid fossa

The integrity of the articular (cortical) surface itself

0 = continuous

1 = discontinuous

2 = not applicable (due to sclerotic underlying bone)

Flattening of the condyle—sagittal view^b

A flattening change from the expected rounded/ovoid shape

0 = absent, i.e. rounded/ovoid

1 = subtle anterior flattening

2 = mild flattening, involves part of the surface of the condyle

3 = Moderate/severe, involves the entire surface of the condyle, or loss of height of the condyle

Flattening of the condyle—coronal view

A flattening change from the expected convex shape

0 = absent, i.e. convex throughout

1 = mild or partial flattening

2 = moderately or severely flattened, or flattened throughout

Reduced condylar volume^c

Generally reduced condylar volume. The condyle is defined cranial to the ‘equator’, i.e. the anterior, posterior, medial and lateral points of maximum convexity when the condyle and neck is viewed in the sagittal and coronal view, respectively

0 = normal

1 = mildly reduced volume/height (clearly above ‘equator’-level)

2 = moderately reduced volume/height (does not cross ‘equator’-level)

3 = severely reduced volume/height (‘equator’-level or lower, yet still fan shape in coronal view)

4 = cylinder shape in coronal view

Surface irregularity of the condyle^b

Irregular change(s) of surface shape, for example depression. More distinct and sharply demarcated than ‘flattening’. May be continuous or discontinuous

0 = absent

1 = mild (involving only part of the articular surface, including multiple depressions/lesions)

2 = moderate/severe (involving the entire articular surface, or presence of deep brakes in the subchondral bone seen in two planes

Continuity of the condylar surface

The integrity of the articular (cortical) surface itself

0 = continuous

1 = discontinuous

Position of the condyle in the temporal fossa

0 = neutral

1 = anterior

2 = posterior

3 = medial

4 = lateral

5 = superior

6 = inferior

Subchondral sclerosis of the articular eminence and glenoid fossa^d

A thickening of the cortical bone (load-bearing) and unequivocal involvement of the subchondral bone

0 = none

1 = thickened cortical bone

2 = subchondral sclerosis

Osteophyte of the articular eminence and glenoid fossa^e

Marginal hypertrophy with sclerotic borders and exophytic angular formation of osseous tissue arising from the surface

0 = absent

1 = present

Subchondral pseudocyst of the articular eminence and glenoid fossa

A cyst-appearing cavity underlying the articular surface. To be discerned from variation of the trabecular bone

0 = absent

1 = present

Subchondral sclerosis of the condyle^d

A thickening of the cortical bone (load-bearing) and unequivocal involvement of the subchondral bone

0 = none

1 = thickened cortical bone

2 = subchondral sclerosis

Osteophyte of the condyle^d

Marginal hypertrophy with sclerotic borders and exophytic angular formation of osseous tissue arising from the surface

0 = absent

1 = present

Subchondral pseudocyst of the condyle

A cyst-appearing cavity underlying the articular surface. To be discerned from variation of the trabecular bone

0 = absent

1 = present

Bone apposition

Bony contact between the condyle and temporal bone

0 = absent

1 = present

Ankylosis

Continuous structure between the condyle and temporal bone

0 = absent

1 = fibrous (suspected)

2 = osseous

Loose joint body^d

A well-defined calcified structure that is not continuous with the osseous structures of the joint

0 = absent

1 = present

Heterotopic calcification

0 = absent

1 = present