The specific sagittal magnetic resonance imaging of intradural extra-arachnoid lumbar disc herniation

Abstract

Intradural extra-arachnoid lumbar disc herniation is a rare disease. Few MRI findings have been reported. We experienced an intradural extra-arachnoid lumbar disc herniation. We reviewed the preoperative MRI findings. Lumbar spine T2-weighted sagittal MRI showed that one line of the ventral dura was divided into two by a disc herniation. We speculated that the two lines comprised the dura and arachnoid and that a disc herniation existed between them. We believe that division of the ventral dural line on T2-weighted sagittal images is a characteristic finding of intradural extra-arachnoid lumbar disc herniation. The division of ventral dural line seemed to be a Y, and, thus, we called it the Y sign. The Y sign may be useful for diagnosing intradural extra-arachnoid lumbar disc herniation. © Copyright 2012 Tatsuro Sasaji et al.