Upright CT Myelography Exposes Dynamic Canal Narrowing Missed Supine in Intradiscal Vacuum Phenomenon

Standing weight-bearing CT myelography revealed disc space collapse, increased posterior disc bulge, and severe canal narrowing not apparent on supine imaging in 3 patients with intradiscal vacuum phenomenon (IVP), suggesting supine studies may miss dynamic stenosis.

• Retrospective case series of 3 patients with IVP who underwent both supine and standing cone-beam CT myelography.
• In all cases, upright imaging showed dynamic disc collapse and canal narrowing that was underestimated or absent on recumbent images.
• Very small, selected sample; hypothesis-generating only—prospective studies needed to define the predictive value of IVP for dynamic compression.

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