Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
There are multiple causes for these changes. Most often, these are due to what is called "chronic small vessel disease", literally meaning diseased small vessels that supply blood flow to the brain. This is not an uncommon process in the brain and increases with age. This is not a disease in and of itself but rather is a reflection of unhealthy blood vessels, damaged by years of plaque build-up. This is most often due to a combination of several factors including the following: high blood pressure, diabetes, smoking, and high cholesterol. If these factors are well controlled, the damage to the brain can be stabilized and further damage prevented.
Other causes of these changes in the brain can be migraine. People with migraine often have plaques on their MRI that are of unclear cause or significance.
Other causes of plaques on MRI can usually be distinguished based on history and symptoms, such as symptoms of neurologic deficit (for example arm weakness or difficulty walking etc). These can also be distinguished based on the MRI appearance. These include, but are not limited to, multiple sclerosis, other demyelinating disease, and inflammatory processes such as vasculitis.
If you smoke, have high blood pressure, high cholesterol, or diabetes, it is imperative that you stop smoking, take medication to control your blood pressure, cholesterol, and diabetes, eat a healthy diet, and exercise.
Hope this information was helpful!