The correlations of single photon emission computed tomography joints scan and bone metabolic markers in active rheumatoid arthritis

Abstract

Objective: To explore the correlation between quantitative value of joint bone scan by single photon emission computed tomography(SPECT) and serum bone metabolic markers in patients with active rheumatoid arthritis(RA). Method: Clinical data of 60 newly diagnosed RA patients were retrospectively collected in Department of Rheumatology and Immunology from May 2013 to December 2014, including 28 cases with medical history less than 6 months and 32 from 6 months to 2 years. Serum C-terminal telopeptide of type Ⅰ collgen(CTX-Ⅰ)and N-terminal propeptide of type Ⅰ collagen(PINP)were tested by chemiluminesence. SPECT whole body bone and target joint scan before treatment was done. Thirty-nine healthy subjects as control group received ultrasound, electrocardiogram, X-ray, and whole body bone imaging examination. Quantitative values of joint imaging were calculated for the statistical analysis. Result: Demographic data between RA group and control group were comparable (P>0.05), including sample, sex, age and BMI. The joint SPECT value, CTX-Ⅰ and PINP levels were all significantly higher than those of control group (P<0.01), which were 6.48±1.98 versus 3.73±1.16; (0.66±0.37) mg/L versus (0.58±0.21) mg/L; (46.35±28.15) mg/L versus (30.47±13.75) mg/L respectively. Joint SPECT values had positive correlations with serum CTX-Ⅰ levels in all RA patients, as well as PINP in patients with disease duration 6mon-2years. And the according correlation coefficients were 0.513, 0.495, 0.402(P<0.05). But SPECT value had no correlation with CTX-Ⅰ (P=0.081) in patients with disease duration less than 6 mon.The correlation coefficient was 0.336. Conclusion: SPECT imaging quantitative values were positively correlated with serum bone metabolic parameters. Thus SPECT imaging alone or combined with bone markers are helpful in diagnosing active RA.