Apparent diffusion coefficient and T2* mapping on 3T MRI in normal and degenerative lumbar intervertebral discs

Area of Science:

• Radiology and Imaging
• Biomedical Engineering
• Orthopedics

Background:

• Lumbar degenerative disc disease (LDDD) is a significant cause of low back pain.
• Current grading systems, like the modified Pfirrmann grading (MPG), rely on subjective visual assessment.
• Objective quantitative methods are needed for accurate LDDD assessment.

Purpose of the Study:

• To evaluate the effectiveness of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps and T2* mapping.
• To quantitatively analyze nucleus pulposus (NP) and annulus fibrosus (AF) in lumbar intervertebral discs.
• To correlate these quantitative measures with the modified Pfirrmann grading (MPG) for LDDD.

Main Methods:

• 100 subjects underwent T2-weighted, DWI with ADC, and T2* MRI.
• MPG was applied to L3-L4, L4-L5, and L5-S1 discs.
• ADC and T2* values of NP and AF were calculated using regions of interest (ROIs).

Main Results:

• 300 discs analyzed: 68 normal (Grade I), 232 degenerated (Grades II-VIII).
• Degenerated discs showed significantly lower T2* and ADC values in NP, AF, and the entire disc compared to normal discs.
• Significant negative correlation (p < 0.001) between ADC/T2* values and MPG. High accuracy (AUC 0.8-0.9) for LDDD assessment.

Conclusions:

• ADC and T2* value-based grading scales offer high accuracy and objectivity for evaluating LDDD, surpassing visual MPG.
• Reduced ADC and T2* values in NP can serve as early biomarkers for LDDD.
• These quantitative MRI techniques provide a reliable method for assessing disc degeneration.