"Small vessel ischemic changes" (also known as "small vessel disease" or "microvascular disease") is medical jargon for fact that there is evidence of old strokes on the imaging study (whether head CT or MRI). These are commonly found on MRIs in people in their 60's and older--even if they have never actually noticed stroke symptoms. A lot of these tiny strokes occur in parts of the brain that don't produce any physical symptoms; or they may have produced symptoms that were so mild, the person never thought much of them. "Small vessel ischemic changes" may represent new or old strokes. If the MRI report does not say "acute strokes" or "restricts diffusion," then chances are they are old strokes. The things that classically cause such strokes are high blood pressure, high cholesterol, diabetes, and smoking. Those are the most common. Migraine headaches can cause similar lesions. There are other less common stroke risk factors that can lead to such lesions; but the four aforementioned are far and away the most common. These lesions themselves can do no more harm. But they indicate that modifications to stroke risk factors need to occur to reduce the risk of having a stroke that may cause significant symptoms (such as weakness or difficulty speaking). In general, when I as a stroke neurologist see these in my patients, I will do a workup to look at their heart function, blood pressure control, cholesterol, blood sugar control, etc.; and if they smoke, I encourage them and try to help them quit smoking. If appropriate, I will start them on a blood thinning medication such as aspirin to help reduce the risk of future strokes.
"Mild inflammatory changes of the mastoid air cells" indicates that the sinus (called teh "mastoid sinus") located behind your ears (within that hard bone just behind your ear) have some inflammation (or swelling) from viral or bacterial (and less commonly fungal) sinus disease. This could be due to acute (i.e. new/recent) sinus infection or chronic sinus infection.