Diagnosis of early sacroiliitis in seronegative spondyloarthropathies by DWI and correlation of clinical and laboratory findings with ADC values.

Purpose: Sacroiliitis is one of the diagnostic criteria of seronegative SpA. The purpose of our study is to show the signal characteristics of the sacral and iliac surfaces by DWI which may contribute in early diagnosis of sacroiliitis and investigate the correlation between ADC values and clinical and laboratory parameters.

Materials And Methods: 62 patients with inflammatory low back pain, with a history or suspect of seronegative SpA are enrolled into the study. 40 age and sex-matched subjects without SpA constituted the control group. After obtaining routine T1 and T2 weighted sequences, echo planar imaging at b values of 0, 400 and 800 was performed. ADC values on both surfaces of the both sacroiliac joints were measured in all subjects. The CRP and sedimentation results and the presence of arthritis and enthesitis were also correlated with the ADC values.

Results: ADC values on both surfaces of the both sacroiliac joints were found 0.23 × 10(-3)mm(2)/sn in the control group. In the patient group, mean ADC value of 0.48 × 10(-3)mm(2)/sn was obtained (p<0.001), which was statistically significant, compatible with the increased diffusion due to medullary edema in early sacroiliitis. There was a slight correlation between CRP and ADC values; presumed to be showing the relation between the activity of the disease and the active inflammation on DWI. There was no correlation between arthritis and enthesitis and the ADC values (p>0.001).

Conclusion: DWI, by measuring ADC values, adds significant information in the early diagnosis of sacroiliitis and may help to evaluate the efficiency of the treatment.