Apparent diffusion coefficient values in Modic changes - interobserver reproducibility and relation to Modic type.

Area of Science:

• Radiology and Imaging
• Spinal Imaging
• Biomarker Discovery

Background:

• Modic Changes (MCs) are vertebral bone marrow abnormalities with uncertain clinical significance in back pain.
• Diffusion-weighted MRI and apparent diffusion coefficient (ADC) measurements offer insights into bone marrow lesions.
• Limited research exists on ADC measurements within MCs, necessitating studies on reproducibility and validity.

Purpose of the Study:

• To evaluate the interobserver reproducibility of ADC measurements in Modic Changes (MCs).
• To assess the relationship between ADC values and different types of Modic Changes (MCs).
• To determine if ADC measurements can differentiate between MC types (oedema, fatty, sclerotic).

Main Methods:

• Utilized ADC maps from 1.5T lumbar spine MRI scans of 90 chronic low back pain patients.
• Two radiologists independently measured ADC values in MCs using fixed-sized regions of interest.
• Analyzed MC-ADC, MC-ADC%, and MC-ADC-ratio, assessing interobserver agreement and correlation with MC type using statistical models and ROC analysis.

Main Results:

• All ADC variables showed significantly higher mean values for Type 1 (oedema) compared to Type 3 (sclerotic) and Type 2 (fatty) MCs.
• MC-ADC and MC-ADC% demonstrated moderate to high ability to discriminate between MC types (AUC 0.73-0.91).
• MC-ADC exhibited the best interobserver reproducibility, with less frequent large differences between observers compared to other ADC variables.

Conclusions:

• The MC-ADC measurement demonstrated superior interobserver reproducibility and significant ability to differentiate between Modic Change types.
• ADC values varied across MC types consistent with expected histological differences.
• MC-ADC is a reproducible metric that can be utilized in future research on Modic Changes and their clinical relevance.