I read your question carefully and I understand your concern. The headache and dizziness is most probably related to the head trauma, it is common after trauma. As for the small vessel disease that is a coincidental finding, is not related to the trauma or those symptoms. It hasn t happened over night but over many years, would be present if a CT was done before the trauma as well. It is not serious in the sense of life threatening, those are chronic changes of blood vessels over the years. To a degree are part of aging, the older the more likely to find them. However at 52 they are appearing a little early so they do raise some concern and call for attention as if changes progress to severe over the years they do affect performance, cognitive functions. What is necessary is to screen more closely for predisposing vascular risk factors such as high blood pressure, diabetes, smoking, high cholesterol etc and addressing them. That is the only means to at least try (genetic factors play a major role as well and not much can be done about that) to slow their increase in the future. I remain at your disposal for other questions.