Dynamic Fluoroscopic Myelography in the Evaluation of Spinal Dorsal Arachnoid Web

Dorsal arachnoid web is a challenging condition to diagnose on MR imaging. MR imaging flow studies have shown altered CSF flow dynamics near the web. We describe the findings of an arachnoid web with dynamic fluoroscopic myelography in a 77-year-old man. Dynamic myelography revealed functional CSF flow obstruction and focal dorsal thecal sac enlargement with a dynamic change in size at the T6 level.