Whats the difference between an mri and a cat scan? more specifically-why would an ent order one or the other?

There : There is considerable overlap between these two imaging modalities, however there are a few pertinent differences. Mri (magnetic resonance imaging) is generally better suited for characterizing the nature of tissues. While ct (computer axial tomography) uses ionizing radiation and will provide better bone detail. Ct is fast and less expensive. Mri is slow and more expensive. If your ENT is considering sinus surgey, you'll get a ct. If there is a concern for evaluating a mass, you may get an mri. I hope this helps.

Imaging tests: Depends on your condition/symptoms. Ct uses radiation, like multiple x-rays. Mri uses magnets, and is very useful in characterizing soft tissue differences such as in the brain or joints. Ct is better for looking at the bones in and around ear (temporal bones). Mri better for inner ear, nerve roots, etc. Ct also best for sinuses, and is typically used with contrast to evaluate the neck.