White Matter Hyperintensities (WMH)

What are White Matter Hyperintensities?

White matter hyperintensities (WMH), also called leukoaraiosis or white matter lesions, are bright spots that appear on brain MRI scans. They indicate areas where the brain's white matter (nerve fibers) has been damaged or shows abnormal signal intensity.

Imaging Appearance

On MRI, white matter hyperintensities appear as:

• Bright (hyperintense) areas on T2-weighted and FLAIR sequences
• Periventricular (around brain ventricles) or deep white matter distribution
• Confluent patterns in advanced cases (merging lesions)

Clinical Significance

Why do WMH occur?

WMH result from chronic small vessel disease (cerebral microvascular ischemia):

• Reduced blood flow to white matter
• Damage to small arteries (arteriosclerosis)
• Breakdown of myelin (nerve insulation)

Risk Factors

Vascular Risk Factors (Most Important):

• Hypertension (high blood pressure) — strongest risk factor
• Diabetes (high blood sugar)
• High cholesterol
• Smoking
• Aging (very common in people ＞ 60)

Other Factors:

• Migraine headaches
• Genetic predisposition (CADASIL)
• Chronic kidney disease

Clinical Impact

Cognitive Effects

Research shows WMH are associated with:

• Slower processing speed
• Memory difficulties
• Executive function impairment (planning, decision-making)
• Increased risk of dementia

Not everyone with WMH develops cognitive symptoms. The extent and location matter.

Stroke Risk

WMH indicate underlying vascular disease and are associated with:

• Increased stroke risk (2-3x higher)
• Lacunar infarcts (small strokes)
• Cerebral microbleeds

Other Associations

• Gait disturbance and falls in elderly
• Depression and mood changes
• Urinary urgency

Severity Grading

Radiologists often use scales like the Fazekas scale:

Grade 0: No lesions
Grade 1: Punctate foci (small dots)
Grade 2: Beginning confluence of lesions
Grade 3: Large confluent areas

Higher grades correlate with greater cognitive risk.

What Should You Do?

If you have WMH on your MRI:

1. Control Vascular Risk Factors

Blood Pressure:

• Target ＜ 130/80 mmHg
• Take antihypertensive medications as prescribed

Blood Sugar:

• Keep HbA1c ＜ 7% if diabetic
• Monitor glucose regularly

Cholesterol:

• LDL goal ＜ 100 mg/dL (or lower if high risk)
• Consider statins

Lifestyle:

• Quit smoking
• Exercise regularly (150 min/week)
• Maintain healthy weight
• Mediterranean diet

2. Cognitive Monitoring

• Baseline cognitive testing if extensive WMH
• Regular follow-up if symptoms develop
• Brain stimulation activities

3. Follow-Up Imaging

• Usually not needed unless symptoms worsen
• Repeat MRI may be ordered in 1-2 years

Can WMH Be Reversed?

Unfortunately, existing WMH are generally irreversible. However:

• Progression can be slowed with aggressive vascular risk management
• Some studies show intensive blood pressure control may reduce WMH growth

Prognosis

• Mild WMH in elderly individuals are often benign
• Moderate to severe WMH increase dementia and stroke risk
• Aggressive risk factor control improves outcomes

Related Imaging Terms

• Lacunar infarcts - Small deep brain strokes
• Cerebral microbleeds - Tiny hemorrhages in brain
• Brain atrophy - Brain volume loss

Common Questions

Are WMH the same as MS lesions?

No. Multiple sclerosis (MS) lesions have different patterns and locations. WMH from vascular disease are typically periventricular, while MS lesions have specific diagnostic criteria.

Do all older adults have WMH?

WMH are very common in older adults (＞ 90% of people over 60 have some degree), but severity varies.

Will I develop dementia?

Not necessarily. Many people with WMH maintain normal cognition. Risk depends on extent, progression, and other factors.

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Medical Disclaimer: This information is educational. Discuss your MRI findings and risk factors with your neurologist or primary care physician.