Kim et al reported a nomogram for evaluating a patient for temporomandibular joint (TMJ) disk perforation. The authors are from Gangnam Severance Hospital and Yonsei University in the Republic of Korea.
Patient selection: temporomandibular joint disorder, age 15 to 75 years of age
Imaging: MRI
Parameters:
(1) age in years
(2) disc shape
(3) bone marrow signal (BMS)
(4) joint space narrowing
(5) changes of condyle (osteophyte, erosion, sclerosis, flattening, spur) and fossa
points for age =
= (1.605 * (age)) - 24.075
|
Parameter
|
Finding
|
Points
|
|
disc shape
|
biconcave
|
0
|
|
|
folded
|
11.3
|
|
|
flattened
|
41.4
|
|
|
eyeglass-shaped
|
57.6
|
|
|
amorphous
|
91.7
|
|
bone marrow signal
|
normal
|
0
|
|
|
low
|
36.8
|
|
joint space narrowing
|
normal
|
0
|
|
|
narrowing
|
44.4
|
|
|
bone-to-bone contact
|
57.9
|
|
|
bone-to-bone contact open
|
100
|
|
changes of condyle and fossa
|
0 or 1
|
0
|
|
|
2 or more
|
42.1
|
total score =
= SUM(points for all 5 parameters)
Interpretation:
• minimum score: 0
• maximum score: 366.9
X =
= (0.039 * (score)) - 5.7
probability of disk perforation =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve was 0.91 (internal validation) and 0.89 (external validation).
