Does technetium-99m labeled methylene diphosphonates bone scan reliably detect early inflammatory changes in temporomandibular joint arthritis?

Objectives: This study aimed to determine whether technetium-99m labeled methylene diphosphonates ( 99m Tc-MDP) bone scintigraphy can reliably detect early inflammatory changes in temporomandibular joint (TMJ) arthritis.Materials and Methods: A prospective, observational pilot study was conducted between October 2019 and December 2021.Consecutive eligible patients with TMJ pain fulfilling the diagnostic criteria for TMJ arthritis were prospectively enrolled.Following detailed case history and clinical examination, all patients underwent panoramic radiography and 99m Tc-MDP bone scintigraphy.Images were analysed by an expert technician from the Department of Nuclear Medicine.Results: Among 31 subjects, 26 were males, and 5 were females; more than 50% were aged 20-30 years.Preauricular pain was right-sided in 18 and left-sided in 13; 13 subjects had pain within the past two months.Twenty patients had unilaterally missing teeth, 6 had unilateral carious teeth, and 10 had habitual unilateral chewing.Masticatory muscle tenderness, especially unilateral, was present in 29%.Radiographically, 83.9% had no evident bony changes, 9.7% showed bony erosion, and 3.7% had flattening or concavity of condylar articular surfaces.Pain was of mild intensity in 2 and severe intensity in 9 subjects.Seven of 31 patients had abnormally increased uptake in the painful joint compared with the normal contralateral joint.On quantitative assessment of isotope uptake, TMJ count was 47.78±18.18and 44.72±17.43,and TMJ uptake ratio 2.49±1.00 and 2.22±0.97, in painful and non-painful joints, respectively.Conclusion: 99m Tc-MDP bone scan quantitatively differentiated a symptomatic from a nonsymptomatic joint.However, it had limitations as an objective tool for correlating joint uptake ratio with the patient's subjective findings.As bone scintigraphy is a sensitive technique for detecting increased bone metabolic activity, TMJ-specific tracers in future studies may further improve diagnostic accuracy for early detection of clinically suspected TMJ arthritis.