Contrast-enhanced MR imaging in acute lumbar radiculopathy: a pilot study of the natural history.

To prospectively study clinical findings and contrast material-enhanced magnetic resonance (MR) images over time in patients with acute lumbar radiculopathy.Twenty-five patients underwent physical examination and MR imaging at presentation, 6 weeks, and 6 months. Initial symptoms and clinical course were correlated with type, size, location, and enhancement of disk herniations.Eighteen patients had a herniated nucleus pulposus (HNP) at one or more levels, two had synovial cysts and stenosis, and five had normal findings. Patients with an HNP had marginally more severe neurologic symptoms than did patients without an HNP (P = .07) at presentation. Twenty-two patients completed the 6-week examinations and 14 patients the 6-month examinations; three patients were eliminated from the study after surgical treatment. Among HNPs larger than 6 mm, substantial reduction in size was noted in 36% at 6 weeks and in more than 60% at 6 months after presentation.Agreement between clinical and MR findings for level and side of HNP and radicular symptoms was excellent. There was no correlation of pain and disability with disk size, behavior, or type.