Imaging of white matter lesions

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• White matter lesions (WML) are common in normal brain aging and can be detected by Magnetic Resonance Imaging (MRI).
• Distinguishing true WML from physiological aging changes and other pathologies is essential for accurate diagnosis.
• Various hereditary leukodystrophies and acquired disorders can present as WML, requiring careful differential diagnosis.

Purpose of the Study:

• To outline the diagnostic approach for white matter lesions (WML) using MRI.
• To differentiate true WML from normal aging changes and other neurological conditions.
• To review the differential diagnosis of WML, including hereditary leukodystrophies and acquired disorders.

Main Methods:

• Utilizing T2-weighted MRI sequences, including fluid-attenuated inversion recovery (FLAIR), for optimal WML visualization.
• Employing magnetic resonance angiography to exclude large vessel disease and diffusion-weighted MRI to identify acute ischemic lesions.
• Comparing imaging features of WML with known patterns of hereditary leukodystrophies and acquired disorders like multiple sclerosis (MS).

Main Results:

• FLAIR sequences effectively separate WML from cerebrospinal fluid (CSF)-like lesions.
• Abnormal T2 signal on MRI is non-specific and requires correlation with clinical context.
• Hereditary leukodystrophies often present with diffuse, symmetrical abnormalities, while MS shows characteristic patterns including subcortical U-fiber and corpus callosum involvement.

Conclusions:

• Accurate interpretation of WML on MRI requires differentiating them from normal aging and other pathologies.
• A systematic approach combining various MRI sequences and clinical information aids in diagnosing the underlying cause of WML.
• Multiple sclerosis (MS) and small vessel disease are common causes of WML, with distinct imaging features that aid in their differentiation.