Scrutinise carefully (4)
(Other definitions for scan that I've seen before include "Inspect" , "Look at quickly" , "at one's feet?" , "Conform to rules of poetic metre" , "Hercule ---, detective" .)
(Other definitions for examine that I've seen before include "Question (a witness)" , "research" , "Test or study carefully" , "Subject to inspection" , "vet" .)