On MRI, what does a low T2 signal in an intervertebral disc most commonly indicate?

On MRI, what does a low T2 signal in an intervertebral disc most commonly indicate?

• A. Disc hydration
• B. Disc infection
• C. Disc herniation
• D. Disc desiccation/degeneration

Answer: (D)

On MRI, T2 signal tracks water content. Intervertebral discs normally contain a lot of water, so they appear bright on T2-weighted images. When a disc desiccates or degenerates, its water content drops, causing the disc to look darker on T2. This makes low T2 signal in the disc the classic sign of desiccation/degeneration. Disc hydration would keep the signal bright. Disc infection and disc herniation can affect appearance in other ways, but they are not defined by a uniformly low T2 signal in the disc.

On MRI, T2 signal tracks water content. Intervertebral discs normally contain a lot of water, so they appear bright on T2-weighted images. When a disc desiccates or degenerates, its water content drops, causing the disc to look darker on T2. This makes low T2 signal in the disc the classic sign of desiccation/degeneration.

Disc hydration would keep the signal bright. Disc infection and disc herniation can affect appearance in other ways, but they are not defined by a uniformly low T2 signal in the disc.