Comparative Study Of Different ROI Mapping Methods In DTI Spinal Nerve Roots Imaging And Clinical Application

Diffusion tensor imaging(DTI)technique is the only imaging method that can noninvasively detect the structure of nerve fibers in vivo.It allows reconstruction,visualization,and quantitative analysis of neural anatomical connections,to provide more intuitive and abundant image information for determining the pathogenesis and pathogenic mechanism of various central nervous diseases.The DTI research on tumor,brain nerve and spinal cord injury is more in-depth,but the application in spinal nerve root injury is still in its initial stage.The emergence of DTI technology opens up a new method for the display and quantitative analysis of spinal nerve root morphology.However,the measurement accuracy of DTI results is greatly affected by operator factors,such as the size,shape,location,algorithm adopted and familiarity with neuroanatomy of the Region of Interest(ROI),which all affect the accuracy of DTI values and nerve fiber tracer imaging results.Among them,the ROI mapping method is the key factor that cannot be avoided.There have been previous studies comparing the ROI mapping methods of abdominal tumors and brain tumors,but no relevant studies comparing the ROI mapping methods of spinal nerve roots.Therefore,the aim of this study was to explore how to apply DTI techniques in the spinal nerve roots better,by comparing different ROI methods itself influence on measurement results consistency,for establishing the best ROI sketch method,exploring related factors,to try to reduce the effects of related factors,to measure the further application of the DTI values results in spine-related diseases such as cervical spondylotic radiculopathy,lumbar intervertebral disc herniation.Chapter 1:Establishment of ROI mapping method of DTI in cervical nerve roots and clinical correlation analysisThe aim is to establish a reliable method for the ROI mapping of cervical nerve roots and to verify its clinical relevance.In this chapter,we selected 20 healthy volunteers and 20 patients with one-level cervical spondylopathy,and 2 imaging technologists.Four ROI mapping methods were used to measure the FA and ADC values of bilateral cervical 5-8 nerve roots of healthy volunteers,and the FA and ADC values of the corresponding nerve roots on the affected side and the healthy side of the patient,to determine the best consistent method for the ROI mapping of the cervical nerve roots,and then use the DTI values measured by the best method to analyze the correlation of its clinical features.The results show that the maximum circle method has the best consistency.The FA and ADC values of the cervical nerve roots of the healthy patients had no statistical significance compared with those of the healthy side of the patients,but had statistical significance compared with those of the affected side.The FA values and ADC values of the healthy side were significantly different from those of the affected side.In healthy volunteers,the FA and ADC values were correlated with age,body mass index,etc.In terms of patients,the FA values of the affected side,the ADC values of the affected side,the FA value of the healthy side/the FA value of the affected side,the ADC value of the healthy side/the ADC value of the affected side were correlated with the VAS score and ISNCSCI score.These results indicate that the maximum circle ROI mapping method is a reliable method for DTI measuring cervical nerve roots,and the DTI values of cervical nerve roots are clinically relevant.Chapter 2:Establishment of ROI mapping method of DTI in lumbar nerve roots and clinical correlation analysisThe purpose of this study was to establish a reliable method for the ROI mapping of lumbar nerve roots and to verify its clinical relevance.In this chapter,we selected 18 healthy volunteers,21 patients with one-level lumbar disc herniation,and 2 imaging scientists.Four ROI methods were also used to measure the FA and ADC values of bilateral lumbar 3-sacral 1 nerve roots of healthy volunteers,as well as the FA and ADC values of the corresponding nerve roots on the affected and healthy sides of the patients.The best consistent ROI mapping method of lumbar nerve roots was determined,and the DTI value measured by the best method was used to analyze its correlation with clinical features.The results show that the contour method has the best consistency.There was no significant difference between the FA and ADC values of the nerve root of healthy patients and those of the nerve root of healthy patients,but there was a significant difference between the FA and ADC values of the nerve roots of the affected side.The FA values and ADC values of the healthy side were significantly different from those of the affected side.In healthy subjects and patients on the healthy side,FA values and ADC values were correlated with age,body mass index,etc.In terms of patients,FA value of the healthy side/FA value of the affected side and ADC value of the healthy side/ADC value of the affected side were correlated with the VAS,ODI,JOA score,etc.The above results indicate that the ROI method is a reliable ROI method for the lumbar nerve roots,and the DTI value of the lumbar nerve roots is clinically relevant.Chapter three Predictive value of preoperative lumbar nerve root DTI on postoperative recovery of lumbar disc herniationThe objective is to investigate the predictive function of DTI value of lumbar nerve roots in postoperative recovery degree of patients with lumbar disc herniation.A total of 117 patients with single-level lumbar disc herniation were enrolled in a prospective study design.All patients underwent surgical treatment and received DTI,routine MR and X-ray examination within one week before surgery.The recovery rate of Japan Orthopaedic Association(JOA)score was used to evaluate the postoperative recovery.JOA scores were evaluated 1 day before surgery and 12 months after surgery.A JOA recovery rate of less than 50%was defined as an unfavourable outcome.The results showed that the age of the patients in the favorable outcome group was lower than that of the unfavorable outcome group(P=0.005),and the duration of disease was shorter(P<0.001),the difference was statistically significant.The FA and ADC values of the affected side in the favorable outcome group were higher than those in the unfavorable outcome group.The ratio of healthy side FA to affected side FA and healthy side ADC to affected side ADC in favorable outcome group were lower than those in unfavorable group(P<0.05).Logistic regression analysis showed that young age,short course of disease,and low healthy/affected FA ratio were independent factors associated with favorable postoperative recovery.ROC analysis showed that the the affected side FA values and the healthy/affected FA ratio had good predictive performance.These results indicated that the preoperative FA value of the affected side and the ratio of the healthy side to the affected side FA had a good predictive effect on the postoperative recovery of LDH patients.High preoperative FA value on the affected side and high healthy side/affected side FA ratio are more likely to achieve favorable postoperative outcomes in patients with single-level lumbar disc herniation.To sum up,the application of magnetic resonance DTI technology in spinal nerves diseases has a broad space,but at present,it is still needed to optimize the use of methods,and further explore how to use the technology better,so as to provide significant reference value for clinical application.