CT and MRI: What's The Difference?

what the difference between ct scan and mri

Often times, patients ask us “What’s the difference between a CT scan and an MRI Scan?” These scans can seem pretty similar at first glance, but in reality, they are vastly different in the tasks that they perform and their functionality. We’re here to help clear the air and educate patients about the key differences between CT scans and MRI scans.

Basic function

CT scans are most commonly used to view bone injuries, problems in the lungs or chest, and for detecting tumors. MRI’s, on the other hand, are better suited for examining soft tissue injuries, particularly in the ligaments or tendons. They’re also good for spinal cord injuries and brain tumors. Cost:  CT’s are generally less expensive than MRI’s. A CT scan can cost anywhere between $1,200 and $3,200, whereas MRI’s can range anywhere from $1,200 to $4,000.

Radiation Exposure

One of the biggest benefits of an MRI is the fact that the scan is radiation-free. Because the images are produced from a magnet rather than x-ray, patients aren’t at risk of being exposed to any radiation. CT’s, on the other hand, expose patients to low but still significant amounts of radiation.

The average radiation dose of a CT scan can range from 2-10 mSv, which is approximately as much general radiation exposure as someone receives in 3-5 years. Repetitive exposure to higher levels of radiation could potentially lead to cancer, so patients are cautioned against excessive or unnecessary CT scans.

Comfort level/scan time

MRI’s get a bad rep sometimes for the overall patient experience. The scan time is much longer, ranging anywhere from 30 minutes up to two hours, and it’s extremely important for patients not to move while being scanned. Due to the amount of time that patients have to spend with restricted movement inside the machine, anxiety or claustrophobia is common among MRI patients during the procedure.

Although using an open MRI machine instead of a closed one can help soothe patient claustrophobia, there’s nothing that can be done about the amount of time the patient must remain in the machine. This is where CT scans have the upper hand. Most CT scans can usually be completed within 5 minutes, and the actual scan time can be less than 30 seconds, so patients don’t have to worry about claustrophobia.

Shorter scan times also makes for less patient discomfort, and slight movement during the scan isn’t as big of a deal when working with CT’s. CT’s are more commonly used in emergency rooms, specifically because they’re a much faster procedure.

Limitations

Although CT scans are undoubtedly more comfortable for patients than MRI’s are, there are some limitations to both procedures. Although CT’s are great for injuries related to bone, they’re not as versatile as MRI’s are overall. They’re also not as easily equipped for getting multiple angles without moving the patient. While MRI’s can produce images in any plane, there are more limitations about what types of patients can have them.

Patients with cardiac pacemakers, tattoos, and metal implants are sometimes unable to have the procedure. Patients can get a CT scan regardless of metal implants, but anyone who weighs over 450 pounds may not physically fit inside the scanner or may be over the weight limit for the table. MRI’s provide open options that accommodate heavier patients.

It’s important to understand that these scans are used to view different areas of the body. Your doctor will have to decide if a CT scan or an MRI is the right scan for you and your situation. At BICRAD, we are proud to offer both CT scans and MRI scans. If you’re in need of either of these medical imaging scans, contact us here to book an appointment today.