99m Tc-albumin nanocolloid joint scintigraphy in rheumatoid arthritis patients who are in clinical remission - is remission real ?

OBJECTIVES: To make a comparison between the clinical data and the imaging results with 99mTc-nanocolloid scintigraphy in rheumatoid arthritis (RA) patients considered to be in remission.

METHODS: Forty RA patients found to be in clinical remission according to the ACR and the EULAR (DAS28<2.6) criteria were studied. The group included 29 females and 11 males with a mean age of 60.8+/-13.5 years (range 22-86) and a mean disease duration of 13.4+/-7.7 years (range 2-23). The mean time of remission in the study group was 22.2+/-5.2 months (range 11-36). Each patient was given an intravenous injection of 555MBq of 99mTc-nanocalloid (NC). Spot views of the skeleton were taken and a SPECT-CT was done on the wrists and hands. A scan was considered positive when at least one of the hand joints showed increased tracer uptake.

RESULTS: The 99mTc-nanocalloid scintigraphy was negative in 14 (35%) and positive for active joint disease in 26 (65%) patients. Twenty four out of the 26 patients with positive scan (92%) were sero-positive while those who had a negative scintigraphy were all sero-negative except one. No correlation was found between the type of treatment used, the time that elapsed from remission, or laboratory parameters (ESR CRP) and the scintigraphic results.

CONCLUSIONS: The clinical criteria used for remission in RA are not consistent with the actual inflammatory activity in the joints. These results are especially emphasised in the subgroup of sero-positive patients.