Tc-anti-TNF-a scintigraphy in RA: a comparison pilot study with MRI and clinical examination

Objective. To compare the use of radiolabelled human monoclonal anti-TNF-a scintigraphy with clinical examination and MRI of hands and wrists joints in patients with active RA. Methods. Eight patients with active RA, 28-joint DAS (DAS-28)53.2 and a healthy volunteer underwent whole body and hand/wrist scintigraphy after the administration of anti-human TNF-a labelled with technetium-99m (Tc). One hundred and ninety-eight joints were examined. Patients were also given clinical examinations in addition to MRI of the hands and wrists. Results. Of the 198 joints examined, signs of inflammation were detected by MRI in 49 (24.7%) and by scintigraphy in 48 (24.2%) joints, with agreement between the two methods in 44 joints. In five joints, MRI was positive and scintigraphy negative. In another four joints, scintigraphy was positive and MRI negative for signs of inflammation. MRI and scintigraphy were in agreement for negative results for 145 joints. The sensitivity and specificity of scintigraphy was 89.8 and 97.3%, respectively. When clinical parameters (presence of swelling and tenderness of joints) were compared with the MRI findings, lower correlation coefficients were observed (sensitivity of 59.2% and 65.3%, respectively). Conclusions. Scintigraphy using Tc-anti-TNF-a showed high correlation with the presence of inflammatory signs detected by MRI in the hands and wrists of patients with active RA, and demonstrated a greater sensitivity than clinical examination. These results can assist in better understanding of anti-cytokine therapy and support the achievement of evidence-based biologic therapy.