The Specific Sagittal Magnetic Resonance Imaging of Intradural Extra-Arachnoid Lumbar Disc Herniation

الملخص EN

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.