What is the difference between mris & pet scans?

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. A low dose ct is often acquired at the same time as the pet (as in pet/ct scan), to correlate the pet findings with the ct anatomy.
Anatomy. Mri is a picture of structure or anatomy, and does well demonstrating brain pathology with changes in normal anatomy. Pet scanning shows functional metabolic brain derangements, and can illustrate cancers, alzheimer's, various dementias, and abnormal brain handling of normal chemicals such as glucose. Pattens can be diagnostic.
Structure v Function. A pet scan tells us which cells are taking up glucose which is a measure of functioning. Cancer cells take up too much glucose and other illnesses like dementia have cells that do not take up enough glucose. An MRI scan is a structural test and shows the outlines of cells and how big they are. Mri's are often most useful for looking at soft tissue.

Related Questions

What is the difference between pet scans, mri, ct, and bone/gallium scans?

A lot. Sorry to be so vague. They are very different in what can be seen and what can be diagnosed. Not enough room to go through the details. The Internet has many resources for this information. Try this one: http://www.radiologyinfo.org/ Read more...

I want to know what is the difference between pet scans, mri, ct, and bone/gallium scans?

2 groups. Mri and ct scans are typically looking at the anatomy of a patient, as well as differences in blood flow if contrast is administered. Pet, bone and gallium scans are all looking at the function, or physiology of the patient, and the anatomy is of secondary concern. For example, pet scans are usually using f-18 fdg, a glucose analog, and display differences in glucose use, a main energy source. Read more...
Imaging tests. 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, but also is more expensive and takes much more time. Pet is typically used for cancer imaging as it detects glucose usage by tissue (which is greater in tumors). Bone / gallium uses radiotracer.Best i can explain in 400 letters! Read more...

What are the differences between pet scans, mri, ct, and bone/gallium scans?

Precision. Ct is a great screening tool for imaging the organs. Mri images certain tissues more accurately. Pet uses radioactive material to light up specific tissues. Bone scans use activated agents that are taken up selectively by abnormal tissues. Each technique has it's benefits, risks, and degree of precision. Read more...
Many differences. Mri (magnetic resonance) does not utilize ionizing radiation(ir) characterize tissues, extent of tumor, infection, damage to cartilage/ligaments.Bone scan (ir) finds changes in bone reflecting tumors, fxs, infection( sensitive not specific) .Ct (ir) can localize traumatic changes, tumors, appendicitis, kidney disease.Pet/ct (ir) combo isotope /ct finds subtle metastases and recurrent malignancy, . Read more...
Anatomy vs Physiolog. Mri and ct scans are typically looking at the anatomy of a patient, as well as differences in blood flow if contrast is administered. Pet, bone and gallium scans are all looking at the function, or physiology of the patient, and the anatomy is of secondary concern. For example, pet scans are usually using f-18 fdg, a glucose analog, and display differences in glucose use, a main energy source. Read more...