Cartilage and subchondral bone thickness distribution with MR imaging

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Articular cartilage (AC) and subchondral bone (SB) are crucial for hip joint function.
• Accurate measurement of AC and SB thickness is essential for diagnosing and monitoring joint diseases.
• Previous methods for thickness measurement have limitations in accuracy and accessibility.

Purpose of the Study:

• To map articular cartilage (AC) and subchondral bone (SB) thicknesses in human acetabula in vitro.
• To validate AC thickness measurements obtained via magnetic resonance (MR) imaging using light microscopy.
• To assess the correlation between AC and SB thickness and their distribution patterns.

Main Methods:

• Human acetabula were imaged in vitro using fat-suppressed spoiled gradient-recalled acquisition MR imaging.
• Analytic geometry was employed to generate AC and SB thickness maps, correcting for oblique sectioning.
• Light microscopy was used to validate MR imaging-derived AC thickness measurements.

Main Results:

• MR imaging and light microscopy showed standard errors of 0.37 mm (left) and 0.33 mm (right) for AC thickness.
• Subchondral bone (SB) thickness could not be reliably validated with light microscopy.
• Thicker AC was significantly correlated with thicker SB in both acetabula (P < .0001).

Conclusions:

• Combining noninvasive MR imaging with analytic geometry accurately determines AC and SB thickness distribution.
• This approach offers a potential method for quantitative, longitudinal assessment of focal AC defects.
• The findings support the use of MR imaging for in-depth analysis of hip joint structural integrity.