Prognosis value of the ratio of signal intensity on MRI in cervical spondylotic myelopathy / 中华骨科杂志

ABSTRACT

Objective To investigate whether increased signal intensity (ISI) can help assess the prognosis in patients with cervical spondylotic myelopathy (CSM) by means of measuring the ratio of signal intensity. Methods A retrospective study with two or more years follow-up of 57 patients with CSM underwent posterior cervical decompression were carried out from February 2000 to February 2006. 1.5T MRI was performed in all patients before surgery. T2-weighted images (T2WI) of sagittal ISI on the cervical spinal cord were obtained, For those with ISI, the values of signal intensity of the spinal cord on T2-weighted image (T2Wl) and TI-weighted image (TIWI) of sagittal view were measured at the location where there was ISI on T2WI, and the ratio of signal intensity of T2WI / T1WI (T2/T1 ratio) at the same level of the spinal cord and with similar area was calculated on the computer. Patients with ISI were subdivided into 2 groups according to T2/T1 ratio. Results ISI was not observed in 20 patients (group 1). The range of T2/T1 ratio of other 37 patients was from 1.28 to 2.80 and the median was 1.65. Nineteen patients were divided into group 2 (ratio range, 1.28-1.63), and 18 into group 3 (ratio range, 1.67-2.80). Significant differences were noted in age at surgery, duration of disease, recovery rate, pre and preoperative JOA score among three different groups.Spearman's rank correlation showed that T2/T1 ratio was positively correlated with age at surgery and duration of disease, negatively with pre- and postoperative JOA score and recovery rate. Conclusion Patients with ISI and higher T2/T1 ratio tend to have relatively severe preoperative state of illness and poor prognosis after surgical intervention. Spinal cord signal intensity change on T2-weighted MRI might be a predictor of a poor outcome in terms of functional recovery rate in patients underwent operations for multi-level CSM.