ANKLE AND FOOT LESIONS IN RHEUMATOID ARTHRITIS – A COMPARATIVE STUDY OF TRIPLE PHASE 99mTc-MDP BONE SCINTIGRAPHY WITH SPECT/CT, MRI AND USG IMAGING

Abstract

Introduction. Rheumatoid arthritis [RA] is a chronic inflammatory disease of unknown etiology. It marked by a symmetrical, peripheral polyarthritis with many extra articular manifestations. It is a form of chronic inflammatory arthritis which leads to joint damage and physical disability with extra articular manifestations. Evaluation of antibodies, anti-CCPs and rheumatoid factors are routinely used a marker of diagnostic and prognostic significance. The incidence of RA increases between 25 and 55 years of age. Recently imaging modalities like ultrasonography, MRI, bone scintigraphy and PET/CT have been used to provide information about joint inflammation and damage for clinical assessment of RA. Aims: 1) To evaluate the frequency of ankle/foot joint involvement in RA patients, 2) To compare triple phase 99mTc-MDP bone scintigraphy with SPECT/CT, MRI & USG imaging. Materials and method: Study include 50 patients of RA, underwent 99mTc- MDP scan for affected joints. 30 patients further underwent MRI followed by USG. Result: In 50 patients who underwent triple phase bone scan, clearly demonstrated 786 joints involvement. Out of which 280 (~36%) were large joints and 506 (~64%) were small joints. In this 30 patients further underwent MRI. When compared, it suggested fair to moderate agreement between two imaging tools. In our study MRI scan clearly demonstrated the synovial changes as well as bone errosion and marrow edema. Planar and SPECT/CT images are also demonstrated increasing activity at correponding site. Also showed if disease involvement present in clinically silent joints. All three imaging modalities showed some extent of disease present before symptoms of RA become clinically evident. Conclusion: Triple phase 99mTc- MDP bone scintigraphy is an excellent imaging modality for evaluation of all small and large joints in single study. It provides valuable information about the disease activity, number and location of joint involvement. 99m-Tc MDP triple phase bone scan and MRI showed fair to moderate agreement to elicit the disease burden in MTP joints. USG help to detect the syn.