title: MR imaging of lumbar arachnoiditis.
abstract: To assess the usefulness of MR in defining the changes of lumbar arachnoiditis, we reviewed retrospectively the MR, plain-film myelographic, and CT myelographic findings in 100 patients referred for evaluation of failed-back-surgery syndrome. In 11 of 12 cases of arachnoiditis demonstrated by plain-film and CT myelography, an abnormal configuration of nerve roots was seen by MR. The correlated MR and CT and plain-film myelographic changes were divided into three anatomic groups: group 1 showed conglomerations of adherent roots residing centrally within the thecal sac, group 2 demonstrated roots adherent peripherally to the meninges giving rise to an "empty-sac" appearance, and group 3 demonstrated a soft-tissue mass replacing the subarachnoid space. There was one false-negative MR study. For the diagnosis of moderate to severe arachnoiditis, we found MR to correlate excellently with CT myelographic and plain-film myelographic findings.
mesh_terms: D001100:Arachnoiditis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging; D009192:Myelography; D011183:Postoperative Complications / Q000175:diagnosis; D012189:Retrospective Studies; D013126:Spinal Nerve Roots / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed