Intervertebral disk: normal age-related changes in MR signal intensity.

Area of Science:

• Biomedical Engineering
• Radiology
• Orthopedics

Background:

• Lumbar intervertebral discs undergo age-related changes affecting their composition and integrity.
• Magnetic Resonance (MR) imaging is crucial for assessing disc health and detecting abnormalities.

Purpose of the Study:

• To investigate the correlation between chronological age and signal intensity in normal lumbar intervertebral discs using MR imaging.
• To quantify the extent of signal intensity change in discs over an individual's lifespan.

Main Methods:

• Utilized a 1.5-Tesla (T) magnetic resonance (MR) imager to scan 27 human cadavers (newborn to 79 years old) within 48 hours of death.
• Measured signal intensity in the central region of lumbar intervertebral discs on sagittal images acquired with long repetition time (TR) and echo time (TE) sequences.
• Correlated measured signal intensity with the age of the cadavers.

Main Results:

• A statistically significant inverse correlation was observed between the signal intensity of lumbar intervertebral discs and age.
• Despite the correlation, the overall decrease in signal intensity was less than 6% over an 80-year age range.
• The observed decrease in signal intensity is associated with a reduction in disc water and glycosaminoglycan content and an increase in collagen.

Conclusions:

• Age-related changes in lumbar intervertebral discs lead to a gradual, albeit minor, decrease in MR signal intensity.
• These compositional shifts (decreased water/GAGs, increased collagen) are key factors contributing to the observed signal changes during disc aging.
• MR signal intensity can serve as a biomarker for disc aging, reflecting underlying biochemical alterations.