To Explore The Diagnostic Value Of IVIM-DWI In Early Active As Sacroiliac Arthritis

ObjectiveBy MRI diffusion weighted imaging sequence?IVIM-DWI?model based on the Intravoxel incoherent motion?IVIM?,obtaining tissue diffusivity?Dslow?,perfusion fraction?f?and pseudo diffusion coefficient?Dfast?of the bone marrow after sacroiliac joint articular surface,and to assess the diagnostic value of the active ankylosing spondylitis?AS?in early stage.Materials and methodsCollecting the images and clinical data of 42 early active ankylosing spondylitis patients and 40 healthy volunteers from Jan.2017 to Dec.2017,according to the European Spondyloarthropathy Smdy Group?ESSG?and the Bath Ankylosing Spondylitis Disease Activity Index?BASDAI?.According to whether there is definite bone marrow edema in FSE T1WI,FSE T2WI,oblique coronal T2 STIR and DWI?b=600?of the routine sequence images of MRI,the active AS patients can be divided into positive group?n=32?and negative group?n=10?,and the healthy volunteers as control group?n=40?.Measuring the IVIM-DWI related parameters D_slow,f,D_fastast of the three groups.The independent sample t test was used to analyze the statistical differences of IVIM-DWI parameters in each group,and the ROC curve was drawn to analyze the diagnostic efficacy of each parameter in the positive group and control group,the negative group and control group.ResultsThe mean values of D_slow,D_fast and f were positive group(0.75±0.07×10^-3mm²/s,10.76±0.86×10^-3mm²/s,0.47±0.08),negative group(0.34±0.05×10^-3mm²/s,13.02±1.50×10^-3mm²/s,0.45±0.04)and control group(0.34±0.04×10^-3mm²/s,10.51±1.24×10^-3mm²/s,0.38±0.03).The D_fast?t=5.47,p=0.00?and f?t=7.08,p=0.00?in the negative group and control group were statistically different,and the D_slow?t=28.35,p=0.00?and f?t=6.14,p=0.00?in the positive group and control group were statistically different.According to the ROC curve analysis,the optimal critical values?area,sensitivity and specificity?of the negative group and control group were D_fast=11.86×10^-3mm²/s?0.91,90.0%,80.0%?and f=0.41?0.95,90.0%,85.0%?,the optimal critical value of the positive group and control group was D_slow=0.51×10^-3mm²/s?0.97,93.8%,95.0%??Conclusion1.The D_fastast and f in the negative group and control group were statistically different,and the D_slow and f in the positive group and control group were statistically different.2.The differential diagnosis values of Dfast and f were higher when the routine sequence of the early active AS patients had no definite bone marrow edema.The differen-tial diagnosis value of D_slow was higher when the routine sequence of the early active AS patients showed definite bone marrow edema.