Clinical Application Of Magnetic Resonance Diffusion Tensor Imaging In Spinal Cord Neoplasms

Part1:Preliminary study of magnetic resonance diffusion tensor imaging (DTI) on normal spinal cordObjective:Using the magnetic resonance DTI technique to scan the spinal cords of healthy volunteers to investigate the clinical application of the technique.Methods:The spinal cords of24healthy volunteers (mean age34.08±12.63years) were scanned with DTI in different segments, including8cervical spinal cords,8upper thoracic spinal cords, and8lower thoracic spinal cords. Data were analyzed by MedINRIA software. According to the region of interest (ROI) by free hand outlining, the whole spinal cord axial images was taken into the range of ROI. The values of fractinal anisotropy (FA), apparent diffusion coefficient (ADC) and fiber tract (FT) were calculated in each segment, and the fiber tract ratio (FTR) was calculated by FT value of that of the highest segment. We explore the characteristics of healthy spinal cord DTI and diffusion tensor tractography (DTT) and analyze the characteristics of DTI scanning FA, ADC, FT and FTR features in humans with different segments, sex and age.Results:After scanning of the nomal spinal cords, we obtained FA value (0.647±0.065), ADC value (1.175±0.170), FT value (1998±620.9), and FTR value (0.789±0.177). DTI images of spinal cord were normal morphologies, the spinal cords in FA scalar map were mainly blue (spinal axis direction) signals, ADC scalar map of spinal cord were slightly low signals, and fibers tracts in DTT images were naturally placed along the spinal axis direction. After DTI scanning of the cervical, upper thoracic, and lower thoracic spinal cords, FA values of each segment have no significantly different (P>0.05), but ADC, FT and FTR values of each segment were significantly different(P<0.05). Significant differences were also found in FA, ADC, FT and FTR values among different spinal cord segments (P<0.05). However, DTI parameters of spinal cords between different genders were no significantly differences (P>0.05). Age (23～58years) was not significantly correlated with DTI parameters of spinal cords (P>0.05). Conclusions:Spinal cord DTI and DTT images could provide comprehensive information of the spinal cord’s morphology, structure and anisotropy. DTI scanning parameters of spinal cord were different in various segments. Gender and age had no significant effects on DTI scanning parameters of spinal cords. DTI scanning could provide visual and quantitative reference information for the clinical study of the spinal cord. Part2:Clinical application of magnetic resonance diffusion tensor imaging in spinal cord neoplasmsObjective:Using the magnetic resonance diffusion tensor imaging (DTI) technique to scan the spinal cord of patients with spinal cord neoplasms and the control group volunteers, to investigate the clinical application of DTI technology in spinal cord neoplasms.Methods:Spinal cord DTI scans were performed respectively corresponding level on20cases of spinal cord neoplasm patients and20cases of control group subjects. Using the MedlNRIA software to analysis the scan data. According to the region of interest (ROI) by free hand outlining, the whole spinal cord axial images were taken into the range of ROI. The values of fractinal anisotropy (FA), apparent diffusion coefficient (ADC) and fiber tract (FT) were calculated in each level, the fiber tract ratio (FTR1, FTR2) were caculated as the ratio of the middle FT value and the upper/lower FT values. The patients with spinal cord neoplasms were assessed by McCormik classification, Spinal Cord Independence Measure (SCIM) score, American Spinal Injury Association Impairment Scale (AIS) and International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), the ISNCSCI scores including total scores, motor subscores, and sensor subscores. To explore the characteristics of the spinal cord in patients with spinal cord neoplasms and analyze the characteristics of DTI scanning FA, ADC, FT and FTR features in patients and control group volunteers. To analysis the characteristics of extramedullary tumors and intramedullary tumors by spinal cord DTI scanning parameters. To study the correlation between the clinical score in patients and DTI scanning parameters.Results:After scanning of the spinal cords, we obtained the spinal cord neoplasm group subjects spinal average value of FA was0.607±0.104, ADC value was1.405±0.294, FT value was1746±554.4, FTR1was0.739±0.173, FTR2was0.808±0.198. The control group subjects spinal average value of FA was0.649±0.048in control, ADC value was1.161±0.132, FT value was2005.6±403.8, FTR1value was0.998±0.034, FTR2was1.011±0.049. In DTI images, the features of the extramedullary tumors were spinal cord compression and displacement. The main features of the intramedullary tumors were spinal cord shape thickening and abnormal signal. The spinal cords in patients with extramedullary tumors in FA scalar map were mainly blue (spinal axis direction) signals. The signals in spinal cords with intramedullary tumors were mixed.In the ADC scalar maps, the spinal cords with extramedullary tumors showed compression parts slightly high signal, the spinal cords with intramedullary tumor showed increase signal. The DTT images displayed extramedullary tumor fiber tracts of spinal cord compression deformation of intramedullary tumor growth, growth location visible fiber tracts of spinal cord damage. After DTI scaning FA, ADC, FT and FTR values in spinal cord neoplasms group and control group were statistically significant (P<0.05). At the higher spinal cord level, the spinal cord neoplasm group DTI parameter values had no difference compared with the control group(P>0.05). At the lesions level and lower level, the spinal cord neoplasm group DTI parameter values had significant difference (P<0.05) compared with the control group. There were significant differences in the DTI parameters between different level of spinal cords in the spinal cord neoplasm group (P<0.05). There was statistically significant difference between extramedullary tumors and intramedullary tumors in the spinal cord FA value, ADC value, FT value and FTR (P<0.05). The FA value, ADC value, FT value and FTR in spinal cord with neoplasms had significant correlation with McCormik grades, AIS grading and ISNCSCI scores (P<0.05), except the ADC values had no correlation with AIS grades (P>0.05).Conclusions:DTI scan in patients with spinal cord neoplasms can show the morphology of spinal cord, structure and anisotropy changes. DTT images can display the spinal cord fiber tract displacement and damages of spinal cord tumors. DTI scanning parameters values were abnormal in the spinal cord with tumors. There was difference DTI parameters between patients with extramedullary tumors and intramedullary tumors. Parameters of spinal cord tumor DTI scanning value consistent with the clinical scores and neurological function of the patients. DTI scanning parameters can reflect the injury of spinal cord and functions of patients with spinal cord neoplasms.