[A comparative study on the radiographs of spiral CT and cone-beam CT in temporomandibular joint osteoarthrosis].

Objective: To observe and compare the radiographs of spiral CT and cone-beam CT (CBCT) in the imaging of temporomandibular joint osteoarthrosis (TMJOA) and to explore the difference between CBCT and spiral CT in detection accuracy so as to provide references for clinical diagnosis and treatment. Methods: A total of 52 patients with TMJOA diagnosed in the Department of Oral and Maxillofacial Surgery, General Hospital of Chinese PLA, from January 2018 to December 2019 were selected. There were 10 males and 42 females, with an average age of 38.6 years (21-70 years). All patients underwent spiral CT and CBCT examinations. Two oral radiologists and two oral and maxillofacial surgeons measured and evaluated the joint spaces and condylar bone lesions of each side of temporomandibular joint. According to the presence or absence of osteoarthrosis, the patients were divided into osteoarthrosis group (92 sides) and non osteoarthrosis group (12 sides). The mean size of joint spaces and the detection rate of lesions were compared between the two groups. SPSS 20.0 was used to analyze the data. Results: There was no significant difference between the measurements of joint space size and joint position in the spiral CT group and the CBCT group (P>0.05). The mean size of the anterior space and the ratio of the posterior condyle in the osteoarthrosis side were larger than that in the normal side. The LR index was smaller in the osteoarthrosis side than that in the normal side indicating that the position of the posterior condyle in the osteoarthrosis side was deviated. However, the difference was not statistically significant (P>0.05). Both spiral CT and CBCT showed good consistency in displaying condylar osteopathy. The most common types of condylar osteopathy was surface defect. The detection rates of defects by spiral CT were surface erosion (85.6%, 89/104), articular surface flattening and shortening (82.7%, 86/104), subcortical sclerosis (40.4%, 42/104), osteophyte (40.4%, 42/104) and subcortical cyst (11.5%, 12/104) respectively. The detection rates of defects by CBCT were surface erosion (88.5%, 92/104), articular surface flattening and shortening (86.5%, 90/104), subcortical sclerosis (35.6%, 37/104), osteophyte (41.3%, 43/104) and subcortical cyst (11.5%, 12/104). There was no statistical difference between the two groups (P>0.05), respectively. Conclusions: Both spiral CT and CBCT showed good accuracies in displaying the osteopathy of TMJOA and the sizes of the joint spaces measured by spiral CT and CBCT were basically the same. Both spiral CT and CBCT could be used as a routine diagnostic method for TMJOA.