Dual-energy computed tomography collagen density mapping of the temporomandibular disc.

BACKGROUND

The aim of this study was to evaluate the feasibility of dual-energy computed tomography (DECT)-derived collagen density mapping of the temporomandibular disc and to analyze the association with CT-detected joint degeneration and clinically relevant covariates such as age and sex.

METHODS

A total of 155 patients who underwent DECT scan (135 and 80 kVp with 180 and 500 mA) of the neck with clinical indication unrelated to temporomandibular joint (TMJ) disease were analyzed. Collagen density maps were calculated. Region of interest analysis was performed to assess collagen densities of the temporomandibular discs. Osteoarthritis of the TMJ was assessed on a numeric scale of 0 to 2. Generalized estimating equations (GEE) were used to assess the association of discal collagen density (DCD) and patient specific factors.

RESULTS

Osteoarthritis of the TMJ was observed in 86 joints (27.2%), of which 16 (4.7%) exhibited severe degeneration. Unadjusted mean collagen density of the temporomandibular disc was 142.3 HU (SD 42.7; range 11.4–243.2). GEE in the whole cohort showed a significant negative association between DCD and presence of any degeneration (beta − 11.4, 95%CI -22.3, -0.6, p = 0.039) and female sex (beta − 22.8, 95%CI -36.7, -8.8, p = 0.001). Thus, when adjusting for degeneration and age, adjusted mean DCD was 124.4 HU (SD 40.7) in females and 146.3 HU (SD 42.1) in males (p < 0.001).

CONCLUSIONS

Females with TMJ degeneration tended to show lower DCD values compared to males. The quantification of collagen density in the disc provides promising complementary information on structural and functional integrity of the TMJ.