Which MRI sequence is especially useful for identifying demyelinating plaques in the brain?

Which MRI sequence is especially useful for identifying demyelinating plaques in the brain?

• A. T1-weighted sequence
• B. T2-weighted sequence
• C. FLAIR
• D. Diffusion-weighted imaging

Answer: (C)

Demyelinating plaques, like those seen in multiple sclerosis, tend to cluster near CSF spaces in the brain, especially in periventricular and juxtacortical white matter. To pick them out clearly, you want an MRI sequence that suppresses the bright signal from CSF so these nearby lesions aren’t hidden. FLAIR achieves this by nulling CSF signal, which makes demyelinating plaques adjacent to the ventricles stand out as bright spots against a dark CSF background. This contrast is particularly helpful for detecting periventricular lesions and subtle white-matter changes that might be less obvious on standard T2 or T1 images. In contrast, T2 still shows CSF bright signal near the ventricles, which can obscure small plaques; diffusion-weighted imaging highlights acute diffusion changes rather than the chronic demyelination pattern; and T1 imaging may reveal chronic, dark “holes” but is less sensitive for identifying the full extent of demyelinating plaques. So the sequence that best highlights these plaques is FLAIR because it suppresses CSF and enhances visibility of periventricular white-matter pathology.

Demyelinating plaques, like those seen in multiple sclerosis, tend to cluster near CSF spaces in the brain, especially in periventricular and juxtacortical white matter. To pick them out clearly, you want an MRI sequence that suppresses the bright signal from CSF so these nearby lesions aren’t hidden. FLAIR achieves this by nulling CSF signal, which makes demyelinating plaques adjacent to the ventricles stand out as bright spots against a dark CSF background. This contrast is particularly helpful for detecting periventricular lesions and subtle white-matter changes that might be less obvious on standard T2 or T1 images. In contrast, T2 still shows CSF bright signal near the ventricles, which can obscure small plaques; diffusion-weighted imaging highlights acute diffusion changes rather than the chronic demyelination pattern; and T1 imaging may reveal chronic, dark “holes” but is less sensitive for identifying the full extent of demyelinating plaques. So the sequence that best highlights these plaques is FLAIR because it suppresses CSF and enhances visibility of periventricular white-matter pathology.