Few scattered 2-3 mm t2 hyperintense non-specific supratentorial foci involving subcortical white matter. this was my mri impression. please explain?

Nonspecific: Nonspecific findings are nonspecific. Small whilte mater lesions are common and can be due to local ischemia ( lack of blood flow) or inflammation or small infarcts. In the absence of clinical findings they are likely nothing to worry about. What was the reason for your MRI? If vasculitis or M.S is a concern, your doctors will followup and you should get repeat MRI.