High-Resolution Ultrasonography of Temporomandibular Joint in Juvenile Idiopathic Arthritis: a pilot-study

Objectives: To measure the temporomandibular joint (TMJ) lateral periarticular[MOU1] space (LPAS) with High-Resolution-Ultrasound (HR-US) in a patient group (A) with Juvenile idiopathic arthritis (JIA) and in healthy patient group (B) and compare the results to verify TMJ synovitis presence in patients affected by JIA.




Methods: Group A included 14 TMJsof 9JIAchildren (11.3 +/-3.8 years old) with TMJ involvement confirmed by enhancement in Magnetic Resonance (MRI) and group B included 14 TMJ of 7 healthy children (9.2 +/-1 years old).
15MHz high-frequency transducer with linear probe (“MyLab70XVG” Esaote S.p.a., 2009)was used by the same blinded radiologist. [MOU1] The probe was placed over TMJs in Coronal (TMJ longitudinal axis) and Axial (TMJ transverse axis) direction with Closed-mouth (CoC and AxC) and Open-mouth position (CoO and AxO). The TMJ LPAS was identified as the hypoechoic strip measured in orthogonal mode from the lateral cortical profile of the condyle head (hyperechoic signal).The LPASmeasurements in AxC, CoC, AxO, CoO and the average of these 4 measures (AVG) together with the Confidence Intervals (CIs) were compared between group A and group B with 99% confidence (x-2.58xSD/√n<=µ<=x+2.58xSD/√n).


Results: The values of LPAS and CI found were AxO 0.087cm (0.067-0.108), AxC 0.087cm (0.075-0.100), CoO 0.082cm (0.067-0.097), CoC 0.089cm (0.078-0.100), AVG 0.086cm (0.075-0.098) in group A and AxO 0.054cm (0.050-0.057), AxC 0.055cm (0.051-0.058), CoO 0.055cm (0.050-0.059), CoC 0.057cm (0.052-0.062), AVG 0.055cm (0.052-0.058[GF1] [MOU2] [GF3] ) in group B.There is a difference between LPAS values of group A and B and there is no CI overlap. Furthermore, LPAS values of group A are not included in the corresponding CIs of group B. The CoC in group A represented the most homogenous result with the lowest CI width.


Conclusions: LPAS could be used to evaluate the early TMJ involvement in JIA patients and the CoC represents the best modality to evaluate LPAS.