3 T MRI relaxometry detects T2 prolongation in the cerebral normal-appearing white matter in multiple sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• Multiple sclerosis (MS) involves damage not only in visible lesions but also in normal-appearing white matter (NAWM).
• Detecting NAWM damage is crucial for understanding MS progression and developing effective treatments.
• Conventional MRI measures may not be sensitive enough to identify early or subtle NAWM changes.

Purpose of the Study:

• To evaluate a novel 3 Tesla (3T) MRI pulse sequence for detecting tissue damage in the NAWM of MS patients.
• To compare spin-spin relaxometry (R2) measurements in NAWM between MS patients and healthy controls.
• To determine if the novel sequence can identify NAWM abnormalities missed by standard MRI techniques.

Main Methods:

• A novel 3D fast spin-echo pulse sequence was used to acquire T2-prepared images at 3T MRI.
• Transverse relaxation rate (R2) maps were derived from these images to assess NAWM in MS patients (n=13) and normal controls (NL, n=11).
• Global and regional NAWM R2 values, as well as white matter volume fractions, were analyzed.

Main Results:

• Mean NAWM R2 was significantly lower (indicating T2 prolongation) in MS patients compared to controls in the whole brain, frontal lobe, parietal lobe, and corpus callosum genu.
• The R2 histogram peak position was also lower in the NAWM of MS patients.
• Normalized white matter volume fractions did not differ significantly between MS patients and controls.

Conclusions:

• The novel 3D fast spin-echo pulse sequence at 3T MRI can detect tissue damage in the cerebral NAWM of MS patients.
• These findings suggest sub-perceptual tissue alterations in MS NAWM, potentially reflecting demyelination, inflammation, or axonal loss.
• This advanced MRI technique shows promise for identifying MS-related damage that is not apparent with conventional lesion detection or atrophy measures.