Increased signal intensities associated with aging typically have to do with slowly progressive vascular disease that not only affects the brain, but the vascular system in general. It is a common finding in the elderly and is only observed on certain MRI sequences designed to highlight the condition.

There is no part of the brain that "controls muscle weakness." Muscle strength is derived at the muscle tissue level and only conditions that cause muscle wasting which originate in neural tissues can affect muscular agility.

Multiple Sclerosis bears the name for a good reason and typically the numerous lesions of MS are quite characteristic, appearing like rice grains that are most often perpendicular to midline of the brain structure. It is more rare for a single signal intensity to be associated with MS.

The fullness you feel in your throat is more likely due to a phenomenon known as "globus" rather than anything to do with MS. The syndrome of MS actually affects the nerves associated with the larnyx, etc. and causes swallowing and speech problems.

Without the advantage of actually evaluating the MRI films or the radiologist's interpretation, I certainly cannot tell you what I believe it may be, but I think we've spoken before on this topic and again, MS would not be among my impressions. I think you're basing your own interpretations and concerns on a very narrow margin of medical information. There are hundreds of possibilities here, and I'm uncertain why you've become overly focused on MS. As neurologists, we see MS on a regular basis and the characteristic signs and symptoms provide us with a good indication even prior to diagnostic studies.

Reasons for your dizziness would be more appropriately elicited by considering conditions such as benign paroxysmal benign vertigo, meinere's disease, hypotension secondary to anemia, etc.