MRI's use a magnetic field to produce images of internal structures, while CT's require exposure to radiation.

Magnetic Resonance Imaging (MRI) uses a strong magnetic field to temporarily realign hydrogen atoms in your body. Directed radio waves cause these aligned atoms to produce faint radio signals, which are used to form detailed cross-sectional images.

MRI's do a better job of diagnosing issues in your soft tissues, joints, tendons and ligaments. Doctors order MRI's to scan the brain, spine, neck, breast, abdomen and muscles.

While there is no radiation involved in an MRI, it can be a noisy exam and takes longer than a CT Scan. 

Computerized Tomography (CT) is a series of X-Rays taken from many different angles which are combined to create cross-sectional images of bones and soft tissues. CT Scans are painless and typically take only a few minutes to complete.

CT Scans are extremely helpful in diagnosing serious injuries and fractures to bony structures, including the head, chest, abdomen, spine and pelvis. CT Scans are also commonly used to pinpoint the size and location of tumors.

CT Scans are used in emergency rooms as they usually take fewer than 5 minutes to complete and provide higher imaging resolution and less motion artifact due to the fast imaging speed.

Patients with metal implants are able to get CT Scans, but not MRI's... and claustrophobic patients do much better with CT's as they're completed quickly.

The average CT Scan today exposes patients to less radiation than airline passengers receive on long flights. If considering a CT Scan, talk to your doctor about the risks from radiation exposure versus the benefits of early diagnosis.