ADC measurements in various patterns of multiple sclerosis lesions

Area of Science:

• Neuroimaging
• Radiology
• Neurology

Background:

• Multiple sclerosis (MS) is a demyelinating disease characterized by focal lesions in the brain.
• Understanding the heterogeneity of MS lesions is crucial for diagnosis and treatment.
• Diffusion-weighted imaging (DWI) offers quantitative insights into tissue microstructure.

Purpose of the Study:

• To quantify and compare mean apparent diffusion coefficients (ADC) across diverse patterns of focal MS lesions.
• To investigate differences in mean lesion ADC between relapsing-remitting MS (RRMS) and secondary-progressive MS (SPMS) subtypes.
• To explore the correlation between mean lesion ADC and patient disability, assessed by the Expanded Disability Status Scale (EDSS).

Main Methods:

• Conventional and diffusion-weighted MR imaging of the brain was performed on 37 MS patients (26 RRMS, 11 SPMS).
• Apparent diffusion coefficient (ADC) maps were generated, and ADC values were measured for focal MS lesions and normal-appearing white matter (NAWM).
• Lesions were categorized by T1 hypointensity/isointensity, enhancement characteristics, and morphology (confluent vs. discrete).

Main Results:

• A total of 288 MS lesions were analyzed.
• Mean lesion ADC was significantly higher than NAWM ADC.
• Hypointense T1 lesions exhibited higher mean ADC than isointense T1 lesions.
• Confluent lesions showed substantially higher mean ADC than discrete lesions.
• Mean lesion ADC was significantly higher in SPMS patients compared to RRMS patients.
• No significant correlation was found between mean lesion ADC and EDSS scores.

Conclusions:

• Quantitative diffusion-weighted imaging effectively differentiates MS lesions based on their imaging patterns.
• ADC values can help distinguish between different pathological substrates within MS lesions.
• Mean lesion ADC differs between major clinical MS subtypes, suggesting distinct underlying disease processes.