Scientists used cat scans to create a cast of the T-Rex brain cavity
Most convincing of all to many scientists, analysis of Tyrannosaurus Rex skulls shows the presence of unusually large olfactory lobes, which would have been ideal for catching the scent of rotting carcasses from miles away.Its olfactory lobes are half the size of its entire brain.
It also had really small beady eyes but this does not mean it had bad vision.Its snout was sharply pinched to clear its field of vision. Its eyes faced forward to provide some overlap between visual fields from the right and left eyes, permitting stereoscopic vision.
I agree that it did hunt if the oportunity presented itself,but from the evidence,it used its amazing sense of smell alot