AB1192B DIFFUSE WEIGHT IMAGE IS A POTENTIAL MAGNETIC RESONANCE SEQUENCE IN THE PREDICTION OF SPINAL SYNDESMOPHYTE IN YOUNG PATIENT WITH ANKYLOISNG SPONDYLITIS

Background Diffusion-weighted imaging (DWI) is an MRI sequence and has been shown to have advantages over standard MRI sequences in some clinical settings, such as early diagnosis of ischemic stroke and in staging some type of cancers. Different measures of diffusion have been proposed, with the apparent diffusion coefficient (ADC) measure the most widely used. Severe Inflammation leads to higher ADC values through increased water in extracellular, less constrained, spaces. Several studies have investigated the clinical utility of DWI in AS, with suggestive evidence that this sequence has valuable discriminatory capacity between AS and non-inflammatory back pain by inflammation degree on sacroiliac joint (SIJ). Objectives This study was tested the potential capacity of ADC value estimated by DWI on SIJ as the predictor of new spinal syndesmophyte in young patients with ankylosing spondylitis (AS). Methods The 58 patients who fulfilled the ASAS axSpA criteria were enrolled and their age was 18-23 years old. All subjects underwent MRI on SIJ with oblique coronal images parallel to the long axis of the sacrum (fast spin-echo T1WI and STIR) at diagnosis and lumbar spine radiograph at diagnosis, 2 and 4 years sequentially. The ADC value on SIJ measured by DW-MRI at diagnosis and spinal radiographs were scored using the stoke AS Spinal Score (SASSS) at diagnosis, 2 and 4 years continuously. All patients were underwent a detailed clinical evaluation, including the serum erythrocyte sedimentation rate, C-reactive protein, BASDAI, BASMI and BASFI. The univariate and multivariate logistic regression analysis was performed to identify that ADC value on SIJ had an important influence on spinal syndesmophyte growth. Results The ADC value on SIJ showed a positive association with inflammatory marker such as, ESR and CRP, but no association with BASDAI, BASMI and BASFI. However, AS-DAS showed a positive association with ADC value. The high ADC value showed more strongly associated with high SASSS over 2 and 4 years continuously. The univariate logistics analysis showed ADC value and AS-DAS were significant predictors for new spinal syndesmophyte. However, multivariate logistics analysis showed the high ADC value had the highest risk of developing new syndesmophytes in spine. Conclusion This study showed that the inflammation of AS patient was a positive association with ADC value on SIJ by DW-MRI and the measured the ADC value on SIJ by DW-MRI was the modest discriminating capacity method for predicting development of new spinal syndesmophyte in young AS patients. References [1] Sequence in the Diagnosis of Ankylosing Spondylitis Diffusion-weighted Imaging Is a Sensitive and Specific Magnetic Resonance Robinson, Nivene Saad, Kim-Anh Le Cao and Matthew A. Brown Linda A. Bradbury, Kelly A. Hollis, Benoit Gautier, Sateesh Shankaranarayana, Philip C. J Rheumatol 2018;45;771-778 Acknowledgement None Disclosure of Interests None declared