Application of fractional anisotropy entropy in cervical spondylotic myelopathy

Objective: To quantitative analyze the injury degree of cervical cord in cervical spondylotic myelopathy (CSM) patients using fractional anisotropy (FA) entropy of diffusion tensor imaging (DTI). Methods: Twenty-four CSM patients and well-match healthy volunteers underwent cervical cord DTI scanning. FA value was measured at each segment of spinal cord (including grey matter and white matter) of spinal cord level and intervertebral disc level. Further Shannon entropy of FA value was calculated in each segment to observe the disorder degree of cervical cord structure in CSM patients. After the analysis of homogeneity of variance, two samples t test analysis was used to identify FC's differences of FA and Shannon entropy of FA value between the two groups. Result: In CSM group, the average FA value of whole cervical cord was 0.644 ± 0.056, while it was 0.672 ± 0.035 in the healthy control group. There was significant difference of FA values between the two groups (t = -2.049, P = 0.046). The FA entropy of CSM patients' cervical cord was 0.687 ± 0.043, while it was 0.854 ± 0.027 in the healthy control group. The FA entropy of CSM patients' cervical cord was lower than that of control group. There was significant difference of FA entropy between the two groups 12.100, P < 0.001). The significant difference between the two groups was only found at C6 level for each level's FA value. The FA entropy of GSM patients' cervical cord was significantly lower than that of control group for every level. Conclusion: This decreased FA entropy of cervical cord in CSM patients indicates that FA entropy can be used to detect the disorder of cervical cord structure in CSM patients. (authors)