Main conclusions:
- When comparing CT scans with MRIs, remember that both can help identify cancer and other diseases.
- MRI scans better assess the flow of body fluids, provide better soft-tissue contrast, and can image tissue close to the bone.
- CT scans are preferred for identifying specific cancers such as lung, liver and pancreatic cancer, but CT scans expose you to ionizing radiation.
- Both exams are painless, non-invasive and proactive ways to protect your health.
While doctors sometimes askan MRI(magnetic resonance imaging) ora CT scan(CT scan) to help diagnose an illness or medical condition, it's good to know that we can take control of our own health by opting for annual screenings. It is important to understand the differences between a CT scan and an MRI scan.
Oncologists in particular often use this type of imaging to find and classify cancer.
A CT scan uses multiple X-rays to create detailed images of organs, bones, and other soft tissue. The images are used to create three-dimensional images that can reveal abnormalities.
Nuclear magnetic resonance imaging (MRI) also creates detailed images, but instead of ionizing radiation, it uses a powerful magnet and radio waves to create images inside your body.
Likewise, these images can show the difference between normal and diseased tissues.
What are the differences between a CT scan and an MRI?
MRIs and CT scans provide more detailed and higher resolution images than X-rays, ultrasounds or PET scans.
Positron emission tomography, also known aspet scan, can be used to see how your organs and tissues are working. A PET scan uses a radioactive drug (tracer) so your doctor can see what's going on inside your body.
While an x-ray can be used to examine most parts of the body, x-ray images are typically used to detect broken bones or joints in the skeletal system.
Ultrasound uses high-frequency sound waves that bounce off internal organs to create images of the inside of the body. Ultrasound is safe for pregnant women and fetuses.
Other reasons for an X-ray scan can include torn ligaments, arthritic conditions or degenerative disc disease, traumatic brain injury, bone density, as well as other soft tissue issues.
Your doctor will make imaging recommendations to your radiologist based on your symptoms.
If your doctor suspects an aneurysm, brain tumor, breast cancer, pancreatic cancer, or cancer elsewhere in the body, he or she may order a CT scan or MRI scan.
An MRI is more likely to be indicated if a detailed picture of tissues, spinal cord, ligaments, bones or organs is needed.
If general imaging is required, it is more likely that a CT scan or CT scan will be ordered, mainly because CT scans are more cost-effective.
Both MRI and CT scans can be used to determine the best biopsy site for a definitive cancer diagnosis.
Either scan can give your oncologist a clearer picture of where the cancer has spread in your body.
MRI scans explained
MRI scans provide a detailed picturewithout the use of X-rays or ionizing radiation, and they are non-invasive.
MRI scans are large machines shaped like a long donut and use radio waves and strong magnets to visualize the body's bones, tissues and organs.
An MRI machine creates a strong magnetic field and uses radio frequencies to bounce off fat and water molecules. The radio waves go to a receiver that creates an image that can show bone and soft tissue abnormalities.
MRIs are rarely used for "whole body" imaging, mainly because MRIs are relatively expensive. Instead, MRI scans often focus on specific areas, such as joints, the cardiovascular system, the breasts, or the brain.
MRI machines are noisy and often closed. Claustrophobic patients may find it difficult to remain stationary at the machine for extended periods of time. In that case, an open MRI or sedation may be the answer. If you have claustrophobia or confined space anxiety, let your technologist know.
recommended reading–Facing Your Fears: An MRI Guide to Dealing with Claustrophobia
Scans can take anywhere from 30 minutes to an hour, and some people are bothered by loud noises. The technician will likely offer you headphones and the opportunity to listen to your favorite music or audiobook.
You will need to stand still during the scan.
MRI scans offer many benefits:
- An MRI provides better soft-tissue contrast than a CT scan.
- An MRI can help assess the flow of blood and other fluids, organ contractions, and relaxation.
- An MRI can obtain images of tissues surrounded by bone, such as the spine.
- Unlike a CT scan, MRIs do not use ionizing radiation.
Are MRI scans safe?
The short answer is yes, an MRI is generally safe and non-invasive.
An MRI may not be safe for patients with metallic implants that are unsafe for MRIs, pacemakers, insulin pumps, or other medical devices. Radiofrequency, along with magnetic fields, can cause implant devices to heat up. This can cause tissue burns around the implant.
CT scans explained
Sometimes called a CT scan, CT scan, or CT scan, this scan can target a specific area, or it can be a full-body scan.
Your doctor may order the scan with or without contrast. Contrast medium uses a dye to define organs or blood vessels.
Like an MRI machine, a CT scanner is a donut-shaped machine. However, it is shorter and more open than an MRI machine.
Just like with an MRI, you'll lie on a table that slides through the "hole" and have to stay still.
A CT scan uses several x-rays that are passed through your body at different angles.
Different parts of the body create variations in exposure and the computer builds a three-dimensional image. The X-ray machine inside a CT scanner can see hundreds of degrees of tissue density, allowing for detailed images of internal organs.
CT scans are widely preferred by oncologists for the clinical diagnosis of various types of cancer such as lung cancer, liver cancer and pancreatic cancer. The scan provides detailed information about how big the tumor is, where it is located, and whether the cancer has spread.
Low-dose versus normal-dose CT scans
The main difference betweenlow dose computed tomographyand the normal CT scan is the amount of radiation emitted. A low-dose CT scan emits five times less radiation than a normal or standard dose CT scan.
Low doses are mainly used in people who are at very high risk of developing lung cancer or in patients who already have lung cancer.
Are CT scans safe?
CT scans are not invasive but use ionizing radiation to create images of the inside of the body.
Before having a CT scan, you should speak with a doctor to understand the risks and benefits of a CT scan. A CT scan can improve diagnoses, limit unnecessary medical procedures, and improve the overall effectiveness of treatment. CT images can include bone, soft tissue and blood vessels at the same time.
People at high risk of lung cancer should only have a low-dose CT scan to minimize exposure to ionizing radiation.
Radiation can also be harmful to unborn babies. Therefore, pregnant women should not have CT scans.
A CT scan with contrast can be a problem for people who are allergic to the contrast material and for people with kidney problems.
The importance of CT versus MRI screening for cancer prevention
Preventive medicine can provide early detection of the disease, lead to more successful treatment, and prevent complications.
According to a study carried out by the Canary Islands Foundation,your chances of surviving the cancer are better if it is diagnosed while it is still confined to the organ of origin (stage I). Survival rates decline as tumors increase in size and spread regionally (stages II, III) or distantly (stage IV).
In most cases, your doctor will recommend the appropriate test for your suspected condition. Alternatively, you may choose to have regular screening exams as a preventative measure.
According to cancer screening guidelines, screening for colon cancer, lung cancer, breast cancer, and uterine cancer is recommended; however, most other cancers currently do not have recommendations.
At ezra, we created afull body MRI scan, which detects cancer and pre-cancer warning signs in fourteen different organs, including the brain, spine, liver, gallbladder, and pancreas, among others.
Scheduling an elective MRI or CT scan without a doctor's order
Early detection through cancer screeningIt is the best defense against cancer.
In most cases, your doctor will order an MRI or CT scan to help diagnose or evaluate a specific disease or condition. However, more people are choosing to have an elective MRI or CT scan without a doctor's referral.
At Ezra, our team of medical providers will review your medical information and provide you with the referral prescription to get you the test you need.
As a preventive measure, you can choose toschedule an MRI or CT scanannually, giving you more control over your own health and well-being.