Intermediate
Technical
IVT
vacuum phenomenon
Gas accumulation within degenerated intervertebral discs appearing as dark areas on CT imaging.
Full Definition
The vacuum phenomenon refers to the presence of gas, typically nitrogen, within degenerated intervertebral discs that appears as hypodense (dark) areas on CT scans and as signal voids on MRI. This finding indicates advanced disc degeneration with loss of disc height and hydration. The vacuum sign is often associated with instability and can help differentiate degenerative changes from infectious processes. Recognition of this phenomenon is important for surgical planning and understanding the extent of degenerative disease.
Usage
Usage note: Distinguish from pathological gas production in infection.
In Context
- "CT imaging demonstrated vacuum phenomenon at L4-L5 consistent with advanced disc degeneration." — Radiology interpretation
- "The presence of vacuum phenomenon helped rule out infectious discitis in the differential diagnosis." — Diagnostic evaluation
Also known as
vacuum disc
gas phenomenon
Don't confuse with
disc calcification
gas-forming infection