RT Journal Article SR Electronic T1 Epidural Fibrosis and Recurrent Disk Herniation in the Lumbar Spine: MR Imaging Assessment JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 169 OP 178 VO 9 IS 1 A1 Carl V. Bundschuh A1 Michael T. Modic A1 Jeffrey S. Ross A1 Thomas J. Masaryk A1 Henry Bohlman YR 1988 UL http://www.ajnr.org/content/9/1/169.abstract AB Twenty patients were enrolled in a prospective study to evaluate MR imaging in the differentiation of epidural scar and herniated disk material. Fourteen patients had surgical verification of imaging findings. In 12 (86%) of these patients, the MR interpretations fully agreed with the observations at surgery. Careful integration of the findings on sagittal and axial T1-weighted images with more T2-weighted axial images was important for analysis. Anterior and lateral recess scars were hypo- or isointense on T1-weighted sequences and hyperintense on more T2-weighted sequences relative to the “parent” anulus intensity. Free fragments demonstrated a slightly hyperintense signal intensity on T1-weighted images relative to epidural fibrosis but had a similar hyperintense signal intensity on T2-weighted sequences. Prolapsed or extruded disk fragments were hypo- or isointense relative to the parent anulus on all sequences. Morphology, epidural location, mass effect, and often signal intensity were the important parameters by which scar and herniated disk could be differentiated with MR.