Application Of Magnetic Resonance Diffusion Tensor Imaging In Paralumbar Muscle Group In Patients With Ankylosing Spondylitis

Objective:To investigate the application value of magnetic resonance diffusion tensor imaging(DTI)in the paravertebral muscle group injury in patients with ankylosing spondylitis(AS).Methods:A prospective study of 57 AS patients and 46 healthy controls was collected.All subjects underwent conventional MRI imaging and DTI scans of the paralumbar muscle group.Measured and compared the value of ADC and FA in the both sides of the lumbar multifidus and erector spinae and between the test group and the control group.To reconstructe and compare the diffusion tensor fiber bundle diagram.55 AS patients were subjected to CT scans of bilateral sacroiliac joint and divided into grade 2(n=23),3(n=16)and 4(n=16)groups according to the "Lee criteria".The differences in DTI parameter values of the paralumbar muscle groups between the three groups were compared;the DTI parameter values of the AS groups at different levels were compared with the control group.Results:There were no significant difference in the value of ADC and FA on the both sides of the lumbar multifidus and erector spinae in 103 subjects(P>0.05).In the test group,the FA values of the right multifidus and bilateral erector spinae were 0.274±0.030,0.287±0.032,0.282±0.032,and the ADC values of bilateral multifidus were(1.667±0.100)×e-9mm2/s,(1.677±0.116)×e"9mm2/s,respectively,the difference was statistically significant compared with the control group(P<0.05).There were no significant difference in the value of ADC and FA of multifidus muscle and spinal muscle in the AS 2-4 group(P>0.05).The ADC values of bilateral multifidus in the grade 2-3 group of AS patients were as follows:(1.680±0.072)×e-9 mm2/s,(1.702±0.104)×e-9mm2/s,(1.676±0.096)×e-9mm2/s,(1.685±0.099)×e-9mm2/s,respectively,the FA values of the right multifidus and bilateral erector spinae in the grade 2 group as well as right erector spinae in the grade 3 group were as follows:0.264±0.025,0.282±0.033,0.276±0.031,0.284±0.034,respectively,the difference was statistically significant compared with the control group(P<0.05).Conclusion:DTI is technically feasible to evaluate paralumbar muscle injury in patients with AS,and it is expected to provide quantitative information for paralumbar muscle injury in the early stage of AS,and can provide 3D visualization image information of muscle fiber bundle.