(99m)Tc-dextran scintigraphy to detect disease activity in patients with rheumatoid arthritis

To test the applicability of Tc-dextran joint scintigraphy in the assessment of disease activity in patients with rheumatoid arthritis (RA), and to compare it with the clinical disease activity scores and laboratory parameters.

Twenty-seven patients with RA were investigated using Tc-dextran joint scintigraphy. The images were evaluated semi-quantitatively and the regional uptakes of the radiopharmaceutical were calculated for the knee, wrist and ankle joints. The clinical and laboratory parameters were collected and fully analysed. An articular Ritchie index (a tender joint score), the number of swollen joints (Sw), the number of tender joints, the morning stiffness (h), the total Ritchie articular index (R), the visual analogue scale (VAS) and the Disease Activity Score (DAS) were determined for all patients.

Compared with controls, patients with RA had significantly higher regional Tc-dextran uptake in the knee, wrist and ankle joints (P=0.001). The regional Tc-dextran uptake showed no correlation with the patient's age, gender, duration of disease, number of swollen joints (Sw), number of tender joints, morning stiffness (h), VAS, total Ritchie articular index and DAS, or any laboratory parameters. There was a significant correlation between the regional Tc-dextran uptake for individual joints and the articular Ritchie index of the right and left wrist (r=0.42, P=0.03; r=0.45, P=0.02), right and left knee (r=0.66, P<0.0001; r=0.80, P<0.0001) and right and left ankle (r=0.47, P=0.014; r=0.76, P<0.0001), respectively.

This study demonstrates that Tc-dextran scintigraphy is a sensitive method to detect active joint inflammation and could be useful in the management of patients with RA.