Significance of increased signal intensity on MRI in prognosis after surgical intervention for cervical spondylotic myelopathy.

We aimed to examine whether increased signal intensity (ISI) on T2-weighted MRI can be used to predict the surgical outcome of patients with cervical spondylotic myelopathy (CSM). ISI on T2-weighted MRI are frequently observed but the relevance of this finding remains controversial in patients with CSM. Between September 2007 and February 2009, 52 patients with CSM who underwent surgery were studied prospectively. Preoperative and postoperative functional status was evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system, and the recovery rate was calculated using the Hirabayashi method. An MRI was performed on all patients. For those with ISI on T2-weighted MRI, the ratio of the signal intensity on T2-weighted to T1-weighted MRI (T2:T1 ratio) at the same spinal cord level and of similar area was calculated. Although the clinical outcome of all patients had improved at final follow-up, there was a significant difference between patients with ISI and those without ISI in age, duration of symptoms, preoperative and postoperative JOA scores, and recovery rate. The preoperative and postoperative JOA scores and the recovery rate differed significantly (p<0.05) between the three groups: patients without a T2-weighted ISI, and those with different levels of a T2:T1 ratio. Patients with an ISI usually had a low preoperative JOA score and experienced less improvement in neurologic function after surgery. The T2:T1 ratio can be used to help predict surgical outcomes.