T1-Based Synthetic Magnetic Resonance Contrasts Improve Multiple Sclerosis and Focal Epilepsy Imaging at 7 T

Area of Science:

• Neuroimaging
• Radiology
• Medical Physics

Background:

• Ultra-high field (UHF) magnetic resonance imaging (MRI) at 7 Tesla (T) offers enhanced detail for diagnosing brain pathologies like multiple sclerosis and focal epilepsy.
• However, UHF MRI faces challenges including radiofrequency field inhomogeneities that can degrade image quality and hinder interpretation.

Purpose of the Study:

• To develop and evaluate an original synthetic MRI method for generating on-demand T1-based contrasts at 7T.
• To assess the radiological quality of these synthetic contrasts for improved clinical diagnosis.

Main Methods:

• A retrospective study included 21 patients with multiple sclerosis and 35 with focal epilepsy undergoing 7T MRI.
• Synthetic T1-based contrast images were generated using a magnetization-prepared 2 rapid acquisition gradient echo (MP2RAGE) sequence.
• Four radiologists compared synthetic images with conventional MP2RAGE images based on signal homogeneity, contrast intensity, and lesion visualization.

Main Results:

• Synthetic MRI images received significantly higher radiological quality scores across all evaluated criteria (P < 0.0001).
• No radiologist rated synthetic images as markedly worse than original images.
• Synthetic images were rated only slightly less satisfying in 3 epilepsy cases, without impeding lesion identification.

Conclusions:

• T1-based synthetic MRI using the MP2RAGE sequence generates high-quality, on-demand contrasts at 7T.
• This method facilitates lesion visualization in multiple sclerosis and focal epilepsy.
• The technique can potentially reduce overall MRI examination duration by eliminating the need for additional sequences.