Imaging characteristics of intradural disc herniation: A comparison with large disc extrusion

Highlights: • A beak-like shape and calcification of the herniated disc are more likely for intradural disc herniation (IDH). • IDH might show the abrupt discontinuity of posterior longitudinal ligament (PLL) and disc material beyond it. • High maximum herniated disc diameter to central canal diameter ratio increase the likelihood of (IDH). • The Y-sign on ventral dura is pathognomonic to IDH. To compare the computed tomography (CT) and magnetic resonance imaging (MRI) findings of lumbar intradural disc herniation (IDH) and disc extrusion mimicking IDH.