FLAIR² post-processing: improving MS lesion detection in standard MS imaging protocols

Area of Science:

• Radiology
• Neuroimaging
• Medical Physics

Background:

• Advancements in MRI, including higher field strength and optimized sequences, improve multiple sclerosis (MS) lesion detection.
• Multiplying 3D-FLAIR with 3D-T2 sequences (FLAIR²) creates isovoxel images with enhanced contrast-to-noise ratio and white-gray matter contrast.
• FLAIR² improves MS lesion visualization without extending MRI acquisition time.

Purpose of the Study:

• To evaluate the efficacy of 3D-FLAIR² in detecting cortical/leucocortical (LC), juxtacortical (JC), and white matter (WM) lesions in MS patients.
• To compare the lesion detection capabilities of 3D-FLAIR² against state-of-the-art 3D-T2-FLAIR and 3D-T2-weighted MRI sequences.

Main Methods:

• Retrospective analysis of MRI scans from thirteen MS patients with high cortical lesion load.
• Scans were acquired using a 3 Tesla (3T) MRI scanner.
• Manual labeling and counting of WM, JC, and LC lesions were performed on randomized 3D-T2, 3D-FLAIR, and 3D-FLAIR² scans using ITK-SNAP software.

Main Results:

• 3D-FLAIR² demonstrated significantly improved LC lesion visibility compared to 3D-FLAIR (p=0.018) and 3D-T2 (p=0.007).
• On average, 3D-FLAIR² detected 3.2 more cortical lesions than 3D-FLAIR (95% CI -9.1 to 2.8).
• Compared to 3D-T2, 3D-FLAIR² detected an average of 3.7 more LC lesions (95% CI 3.3-10.7).

Conclusions:

• 3D-FLAIR² is a practical, time-saving post-processing method for enhancing cortical lesion detection in MS.
• Further research with larger patient cohorts is recommended to validate the sensitivity and specificity of 3D-FLAIR² for MS lesion detection.