The Utility of Tc-99 m MDP Bone Scintigraphy for the Detection of Articular Involvement in Behçet ' s Disease

Introduction: Behçet’s disease (BD) is a chronic relapsing inflammatory disease. 40-70% of BD patients display rheumatic features with a 9% incidence as an initial presentation. However, there are no pathognomonic laboratory tests in BD and the diagnosis depends on the occurrence and grouping of sufficient clinical manifestations to allow the physician to either suspect, or definitely diagnose the condition. Our aim was to assess the utility of Tc-99m methylene diphosphonate (Tc-99m MDP) bone scintigraphy for the detection of articular involvement in BD patients and its impact on disease activity & severity scoring. Methods: 25 BD patients diagnosed according to the international study group criteria for BD diagnosis (ISG) [18 , 7 , mean age 32.44±7.78, disease duration 6.98±4.61year] were included and subjected to selected joint x-ray and bone scintigraphy. Results: 25/25 was scintigraphically positive for arthritis [100%, 64%, 44%, 40%, 36%& 20% in wrist, Metacarpophalangeal, proximal interphalangeal (PIPs), distal interphalangeal (DIPs), Knees & ankles respectively]. 13/25 were clinically negative while scintigraphically positive for arthritis. 11/25 (44%) and 8/25 (32%) turned from inactive to active BD and from mild to moderate disease severity, based on their positive hand scintigraphy with treatment modification. 4/25 (16%) had recurrent oral ulcers with normal laboratory data and only positive hand scintigraphy; with follow-up they met ISG criteria. Conclusion: skeletal scintigraphy is a simple diagnostic modality with a low radiation burden, when compared to conventional radiology. Hence, when used appropriately in the diagnostic algorithm of BD, bone scintigraphy can be used for detection of early joint involvement, assessment of the extent and activity status with guidance for the selected therapy.