White Spots on the Brain in an MRI

You may have been told that you have “spots” on your brain magnetic resonance image (MRI). Certainly, spots may be a cause for concern, and they may explain the symptoms for which you had your brain MRI. However, there are a variety of explanations for white spots on a brain MRI, and many of them are not alarming.

Your doctor will work with you to determine the significance and cause of the spots based on your medical history, your neurological examination, and your other diagnostic tests, as well as how many spots there are, their size and appearance, and where they are located in the brain.

Spots on a brain MRI are caused by changes in water content and fluid movement that occur in brain tissue when the brain cells are inflamed or damaged. These lesions are more easily seen on T2 weighted images, which describes the frequency (speed) of the radio impulses used during your scan.

White spots may be described in your MRI report as high signal intensity areas (HSIA), white matter hyperintensities, leukoaraiosis (often used if spots are felt to be caused by decreased blood flow), or nonspecific white matter changes.

There are several causes of white spots on a brain MRI, including small strokes, migraines, multiple sclerosis (MS), lupus, B12 deficiency, a brain tumor such as lymphoma, or an infection such as Lyme disease or HIV. They are usually found in the brain’s white matter, typically near the ventricles, but they can be located anywhere in the brain.

Sometimes the white matter hyperintensities can resolve, as with a treated infection or brain tumor. They may temporarily improve and possibly worsen again later, as with episodic inflammatory conditions such as lupus or MS. The spots may shrink in size months after a small stroke, or they may worsen if risk factors for strokes are not treated, leading to further lesions.

Sometimes white spots occur even without symptoms. This is often caused by silent strokes, which are small strokes that don't cause symptoms. They may not cause symptoms if you have enough brain function to compensate for the small area of brain damage.

Silent strokes often occur in a region of the brain called the internal capsule, and are usually caused by blockage of small blood vessels.

Small strokes, the most common cause of white spots on a brain MRI, are often caused by cerebrovascular disease, while large strokes are usually caused by heart disease or carotid artery disease.

Risk factors that lead to and exacerbate these conditions include hypertension, high cholesterol, smoking, an unhealthy diet, diabetes, obesity, or drinking alcohol heavily.

Like many other signs of vascular disease, some people are more at risk for these MRI signal changes than others. A certain degree of white matter change is expected as you age. There tends to be some degree of genetic predisposition, and if you are of Hispanic or African American descent, you are at a higher risk of developing white matter lesions on your brain MRI.

Your doctor can help you understand your MRI findings. Rather than just focusing on these hyperintensities, your doctor can help you identify what risk factors you have that might need addressing.

Often, risk factors require treatment with prescription medications, or even with surgery. Lifestyle strategies, such as a healthy diet, exercise, and even building brainpower, are all associated with a healthier brain.

It can be frightening to hear that there are white spots on your MRI scan.

The cause of these changes is complex, and you may need further testing to find out whether you have an inflammatory disease, a vascular disease, or some other cause. While the lesions themselves are not always treatable, there are a number of effective strategies that can reduce your chances of developing further lesions in the future.