What is a pet scan vs mri? what is the difference between a pet scan and an mri? is either one more comfortable from a patient's perspective?

The : The main differences between a pet scan and an MRI in terms of the information gained from the study are that a pet scan gives functional information whereas an MRI gives anatomic information. In terms of patient comfort, both examinations will require laying very still, usually on the back with arms either overhead or at the sides, for up to 30 to 60 minutes. The pet scan also involves more preparation and time before the actual scanning. For example, fasting for 4 to 6 hours and avoiding exercise for 24 hours, as well as laying quietly for one hour after the injection but before the scanning. A pet scan always involves an intravenous injection of radiotracer. An MRI is sometimes done with an injection (of gadolinium-based contrast medium), but other times is done without any injection, depending on what information is needed from the examination. Typically MRI exams that are performed for tumors or infection will use IV gadolinium, unless there is a specific contraindication to the use of contrast.

Both uncomfortable: Mri is magnetic resonance imaging. It involves lying in a noisy dark tunnel for a long time unable to move. Pet is positron emission tomography that involves being injected with radioactive material and having a special detection device placed over parts of your body to study the take up of material into specific tissues. Both have important clinical purposes and can be necessary.

Anatomy vs Physiolog: Mri and ct look at the structure of the body, the anatomy, and the way diseases change or distort it. Pet looks at the physiology, or how the body uses, or metabolizes something. For pet, the most common metabolism pathway looked at is how glucose is used. Mri is a bit "tighter", longer tube. Pet is more like a ct scanner, but the scan time is much longer, like 20 minutes.