Increased signal located in the "white matter adjacent to the posterior horn of the lateral ventricle" should i worry about this?

Should be followed: This depends on the size of the area of concern. Also, is there any contrast enhancement associated with it? If there is, that is more concerning. Some of the etiologies of white matter increased signal include strokes or demyelinating disease like multiple sclerosis. You should follow up with your neurologist who may want follow-up MRI scans to better clarify and to see if it changes.

Probably not: These may be found in migraine.

Beware of this : It is not at all uncommon for this finding to be reported on an mri. Often the radiologist will say this could be due to "migraines, vasculitis, or lyme disease" it is very important that this result be interpreted by your doctor in the setting of your symptoms.