Leukoaraiosis is a term describing areas of damage in the brain’s white matter, the tissue that connects different brain regions and carries signals between them. These damaged areas show up as bright spots on MRI scans or dark patches on CT scans, most often in older adults. The name comes from the Greek words for “white” and “rarefaction,” coined in the late 1980s to describe these changes. In medical reports, you may also see them called white matter hyperintensities or white matter lesions.
If this term appeared on your brain scan report, it typically points to a type of cerebral small vessel disease, where the tiny blood vessels deep inside the brain aren’t delivering enough blood to the surrounding tissue. It’s one of the most common findings on brain imaging in older people.
What Causes the Damage
The white matter in your brain depends on a constant supply of oxygen carried by small, deep-penetrating blood vessels. When those tiny arteries become stiff, narrowed, or otherwise diseased, the tissue they supply doesn’t get enough blood. This chronic shortage of oxygen and nutrients gradually damages the white matter, creating the lesions that appear on imaging.
The process involves more than simple blood flow reduction. Chronic low blood flow damages the blood-brain barrier, the protective lining that normally keeps harmful substances out of brain tissue. When this barrier breaks down, fluid leaks into the surrounding white matter and causes swelling. Over time, the affected tissue becomes permanently damaged, disrupting the communication pathways between brain regions. This is why leukoaraiosis tends to be progressive: once the small vessels are compromised, the downstream damage compounds.
Risk Factors
Age is the single strongest predictor. The older you are, the more likely these lesions are to appear and the more severe they tend to be. But after age, high blood pressure is the most significant modifiable risk factor. In a large study of nearly 4,700 hospitalized patients, hypertension more than doubled the odds of developing leukoaraiosis (with an odds ratio of 2.4). Hypertension contributes both to the initial appearance of lesions and to their progression over time.
Other established risk factors include:
- Diabetes: Increased the odds of leukoaraiosis by about 60% in the same study, and contributed to worsening over time.
- Smoking: Roughly doubled the odds, particularly for early-onset lesions.
- High homocysteine levels: An amino acid linked to blood vessel damage, associated with a 43% increased risk.
- Alcohol use and high cholesterol: Both were linked specifically to later-stage progression of existing lesions rather than their initial development.
- Sex: Men had modestly higher risk than women.
How It Affects the Brain and Body
Small, mild lesions often produce no noticeable symptoms. Many people learn about their leukoaraiosis only because a brain scan was done for another reason. But as the volume of damaged white matter grows, it can disrupt the brain circuits responsible for thinking, movement, and mood.
The areas most affected tend to be frontal and subcortical pathways, which are critical for executive functions like planning, organizing, and multitasking. People with significant leukoaraiosis may notice they process information more slowly, have trouble concentrating, or struggle with tasks that require mental flexibility. Walking and balance can also be affected because these same deep brain pathways help coordinate movement. Depression is another recognized association.
At its most severe, leukoaraiosis carries serious long-term consequences. Data from the Framingham Heart Study, which followed over 2,200 participants for an average of five to six years, found that people with extensive white matter lesions had more than double the risk of stroke, more than double the risk of death from any cause, and nearly four times the risk of developing dementia compared to those without extensive lesions.
How It’s Graded on Brain Scans
When a radiologist reads your MRI, they typically describe the severity of white matter changes rather than just noting their presence. The most widely used system is the Fazekas scale, which assigns a grade from 0 to 3 based on how the lesions look.
Grade 1 represents small, punctate bright spots. Grade 2 describes lesions that are beginning to merge together. Grade 3 means the bright areas have become large and confluent, forming broad sheets of abnormal signal. Higher grades correlate with greater symptom burden and higher risk of stroke and cognitive decline. Your scan report may reference this scale directly or use descriptive language like “mild,” “moderate,” or “severe” periventricular white matter changes.
Telling It Apart From Multiple Sclerosis
On an MRI, leukoaraiosis can look strikingly similar to multiple sclerosis (MS), since both produce bright white matter spots. This resemblance sometimes causes confusion, especially in middle-aged patients. However, the two conditions differ in important ways on closer imaging analysis.
Location is one key distinction. Leukoaraiosis lesions tend to cluster in the deep white matter, with about 70% of lesions found there in one study. MS lesions, by contrast, are more commonly periventricular, meaning they sit right next to the brain’s fluid-filled cavities, and they also appear near the brain’s outer surface. Another distinguishing feature is the “central vein sign”: because MS attacks tissue around veins, a small vein is often visible running through the center of an MS lesion on specialized MRI sequences. This sign was present in about 73% of MS lesions but only 45% of leukoaraiosis lesions. The pattern of the lesions matters too. Leukoaraiosis tends to be symmetrical on both sides of the brain, while MS lesions are typically asymmetric and scattered. Clinical context, including a patient’s age, symptoms, and lab results, helps complete the picture.
Slowing the Progression
There is no treatment that reverses existing white matter damage. The focus is on slowing progression by addressing the vascular risk factors that drive it. Blood pressure control is the most evidence-backed strategy. A landmark trial published in JAMA found that targeting a systolic blood pressure below 120 mmHg, compared to the standard target of below 140 mmHg, was associated with a smaller increase in white matter lesion volume over time. The difference was modest but measurable, reinforcing that aggressive blood pressure management matters.
Beyond blood pressure, the same vascular risk factors that cause the damage in the first place are the targets for management: keeping blood sugar well controlled if you have diabetes, quitting smoking, reducing alcohol intake, and managing cholesterol. Regular physical activity supports cerebrovascular health broadly and may help maintain blood flow to vulnerable deep brain tissue. Because leukoaraiosis can impair executive thinking skills, catching and managing it early is important: as cognitive function declines, it becomes harder to stick with the kind of complex lifestyle changes that could slow things down.