📌 When Nerve Roots Stop Floating.

https://youtube.com/shorts/M18GXT25oGM

 

Normal MRI Appearance

• Nerve roots are thin, freely floating, and evenly distributed within the thecal sac.
• Sagittal T2: smooth, symmetric fanning of nerve roots.
• Axial T2: multiple discrete nerve root dots surrounded by bright cerebrospinal fluid.

---

Abnormal Findings in Chronic Adhesive Arachnoiditis

1. Nerve Root Morphology

• Nerve roots become moderately thickened due to chronic inflammatory–fibrotic change.

2. Abnormal Distribution

• Loss of normal fanning.
• Nerve roots show clumping rather than free dispersion.

3. Axial Imaging Pattern

• Clumping of nerve roots with pseudotethering.
• Roots appear tethered, reflecting fibrotic adhesion, not true mechanical tethering.

4. Sagittal Imaging Pattern

• Absence of normal root striations.
• Progressive peripheral adherence of nerve roots to the arachnoid.

5. Key Diagnostic Sign

• Central thecal sac appears empty.
• This represents the empty thecal sac sign—
  fluid remains, but central nerve roots are absent.

---

Imaging Interpretation

• This pattern reflects chronic, often “burnt-out” arachnoiditis.
• Enhancement is usually minimal or absent.
• Recognition of this morphology is critical to avoid misdiagnosis and hazardous intervention.

---

Key Takeaway

• Thickened nerve roots
• Loss of fanning
• Clumping with pseudotethering
• Empty thecal sac appearance

→ Think chronic adhesive arachnoiditis.

---

 

#ChronicAdhesiveArachnoiditis, #EmptyThecalSacSign, #NerveRootClumping, #Pseudotethering, #SpineMRI, #Neuroradiology, #MRIpatternRecognition, #RadiologyEducation, #MSKRadiology, #AxialT2, #Vibecase

---

Visualizing MSK Radiology: A Practical Guide to Radiology Mastery
© 2022 MSK MRI Jee Eun Lee. All Rights Reserved.
No unauthorized reproduction, redistribution, or use for AI training.