Intravoxel Incoherent Motion MR Imaging Of Sacroiliitis In Patients With Active Ankylosing Spondylitis:Correlation With Dynamic Contrast-Enhanced MR Imaging

Objective:To investigate the correlation between perfusion-and diffusion-related parameters from intravoxel incoherent motion?IVIM?and those from dynamic contrast-enhanced MR imaging?DCE-MRI?of sacroiliitis in patients with active ankylosing spondylitis.Matrials and Methods:We enrolled 19 patients?male 11,female 8?with ankylosing spondylitis.They were all in active speriod through selecting and evaluating with the blood sedimentation,c-reactive protein and BASDAI?ankylosing spondylitis activity index?with MR imaging performed using a 3.0T siemens MRI scanner.We select the area of bone marrow enhanced as a region of interest from DCE map.Perfusion fraction?f?,tissue diffusivity(D_slow),pseudo-diffusion coefficient(D_fast)were derived from bi-exponential fitting of IVIM data.Transfer constant(K^trans),rate constant(K_ep),extravascular extracellular space?V_e?were derived from DCE data.We investigated the correlation between f,D_slow,D_fast and quantitative parameters K^trans,K_ep,V_e of sacroiliitis in patients with active ankylosing spondylitis.Correlation test was used for statistical analysis.Results:We test all the parameters in normality and find that they do not conform to the normal distribution.Spearman'correlation test was used for statistical analysis.The f were positively correlated with K^trans and K_ep?r=0.854,0.579,p<0.05?.The D_slowlow were positively correlated with K^trans and K_ep?r=0.718,0.495,p<0.05?.The f and D_slow were negatively correlated with V_e?r=-0.691,-0.470,p<0.05?.No correlation was found between _Dfast and any of the parameters from the DCE-MRI in all patients with active ankylosing spondylitis?p>0.05?.Conclusion:IVIM-MR perfusion-related and quantitative DCE-MR parameters were significantly correlated in the assessment of sacroiliitis in patients with active ankylosing spondylitis.IVIM-MR perfusion imaging can be a potential useful non-invasive perfusion imaging tool for clinical use in the assessment of active ankylosing spondylitis.