Multi-modality imaging evaluation of the dorsal arachnoid web

Area of Science:

• Neurosurgery
• Radiology
• Spinal Cord Imaging

Background:

• Dorsal arachnoid web (DAW) is a rare cause of progressive myelopathy.
• The characteristic imaging finding of DAW is the "scalpel sign".

Purpose of the Study:

• To review multi-modality imaging techniques for evaluating dorsal arachnoid webs (DAW).
• To highlight the "scalpel sign" in DAW diagnosis.

Main Methods:

• Retrospective review of 16 patients with DAW from January 2015 to February 2020.
• Utilized conventional MRI, high-resolution MRI sequences, MRI spine CSF flow study, and CT myelogram.
• Correlated imaging findings with clinical data and surgical pathology in five patients.

Main Results:

• The "scalpel sign" was consistently demonstrated across all imaging modalities.
• Syrinx formation occurred in 44% of patients, correlating significantly with cord compression.
• Surgical intervention, including resection and fenestration, led to clinical improvement.

Conclusions:

• The "scalpel sign" is a reliable indicator of dorsal arachnoid webs (DAW) regardless of the imaging modality used.
• Multi-modality imaging is crucial for comprehensive DAW evaluation and effective surgical planning.