Whole-brain atrophy in multiple sclerosis measured by two segmentation processes from various MRI sequences

Area of Science:

• Neuroimaging
• Neurology
• Medical Physics

Background:

• Multiple sclerosis (MS) involves destructive processes leading to brain atrophy.
• Brain atrophy measurement via MRI is a potential marker for disease severity in MS and other neurodegenerative diseases.
• Optimal MRI quantification methods for atrophy remain undefined.

Purpose of the Study:

• To compare the reproducibility of four MRI pulse sequences and two analysis methods (fully automated [FA] and semi-automated [SA]) for brain parenchymal fraction (BPF) measurement.
• To validate the FA technique by assessing atrophy rate in MS patients over nine months.
• To determine the optimal MRI acquisition and analysis strategy for reproducible atrophy quantification in MS.

Main Methods:

• Compared reproducibility of four pulse sequences and FA/SA analysis for BPF in 13 MS patients and 2 controls across two MRI scanners.
• Utilized FA analysis on longitudinal data from 57 MS patients (placebo arm) over nine months to determine atrophy rate.
• Calculated BPF as a normalized measure of whole-brain atrophy.

Main Results:

• All tested pulse sequences achieved a reproducibility of approximately 1% coefficient of variation (CoV) or better.
• 2D multi-slice sequences (conventional spin echo [SE] and fluid-attenuated inversion recovery [FLAIR]) with FA analysis yielded the best reproducibility.
• FA analysis of longitudinal data showed an atrophy rate of -0.5% change in BPF per year.

Conclusions:

• Brain parenchymal fraction (BPF) measurement reproducibility is influenced by both MRI pulse sequence and segmentation method.
• Automated measurement, particularly with 2D sequences, demonstrates high reproducibility for MS brain atrophy.
• Semi-automated measurement may offer higher accuracy but sacrifices efficiency and reliability compared to automated methods.