Old lacunar type infarct within the right caudate head. was wondering what this means as this is from test results 3 weeks ago?

An "old lacunar infarct" basically suggests there was likely a very tiny artery that had the blood supply blocked at one time causing a type of "tiny stroke". These are generally very small (less than 1cm in size)... though technically some use a cutoff number of 15mm. Although these tiny strokes themselves are not usually treated, lifestyle changes may be suggested to prevent future stroke risk.