In one study, researchers evaluated the accuracy of breast cancer recurrence with various screening mechanisms such as MRI (magnetic resonance imaging), CT (computed tomography), X-ray, mammography, and PET scans (positron emission tomography).
They found PET scans were 90% accurate. The other screening procedures combined yielded an accuracy of only 75%.
When comparing PET scan vs. MRI scans, note that both can detect diseases and abnormalities. However, PET scans can show how your body performs at the cellular level.
On the other hand, PET scans include radiation. MRI scans don’t expose you to harmful radiation, which can be preferable for certain patients and annual scans.
Here, we’ll look further into how else PET scans differ from MRIs to help you decide which one you need.
Before we dive into the details, let’s look at the key differences between how a PET scan and an MRI help with medical diagnoses:
Your healthcare provider might order a PET scan or an MRI based on which of the two can better serve the diagnosis.
A PET scan helps to check for signs of:
MRI imaging test helps to check for signs of:
It’s important to note that there are two types of MRI—with contrast and without contrast.
As the name suggests, an MRI with contrast uses a contrast dye, such as iodine or gadolinium, that is injected into your veins to provide much more detailed, high-clarity images that aren’t available without contrast.
Since the density of breast tissue can make it difficult to detect the presence of cancerous cells, be sure to discuss your options with your physician when planning a breast cancer MRI scan.
Recommended reading: What is a whole body MRI screening and why should you get one?
While getting an MRI or a PET scan, your radiologist can inject you with a contrast dye or a radioactive tracer, respectively. These may cause side effects for some people.
The radioactive tracer used in PET scans such as glucose contains a small amount of radiation, so the risk of negative effects is low. However, the tracer can cause the following:
There is no radiation used here, but due to the usage of strong magnets, MRIs cannot be performed on patients with:
MRIs may not be right for pregnant patients. If you believe you may be pregnant, notify your physician.
An MRI screening can cause a harmful increase in the temperature of the amniotic fluid and can be risky to the developing fetus.
If you have an allergy to contrast dye, you might face some allergic reactions from a contrast MRI. Generally, these wear off in an hour or so. However, let your physician know about your allergy before your procedure.
Other side effects can include dizziness, nausea and vomiting, and pain at the site of contrast injection.
The imaging technology of PET and MRI differ in terms of radiation exposure and scanning mechanisms.
PET is a type of nuclear medicine procedure. It uses a small amount of radioactive tracer— glucose, injected intravenously, inhaled in a gas, or swallowed in a drink.
Your oncologist measures the metabolic activity of your cells based on how much tracer they absorb.
Sometimes, instead of glucose, PET scanning can use an analog tracer called fluorodeoxyglucose (FDG). This helps identify malignant cells.
Once you are injected with either glucose or FDG, a whole-body PET scanner will take images to detect abnormalities.
An MRI uses radio waves and powerful magnets to show abnormalities in the body.
You can have an MRI with or without contrasts. In a contrast MRI, your radiologist gives you a contrast dye such as gadolinium or iodine, intravenously.
Generally, a PET scan is used alongside a CT scan (computed tomography) or MRI scan. The PET/CT scan or PET/MRI scan can help health professionals assess the degree of a disease’s impact.
Certain scanning centers use these hybrid PET/MRI scanners to create high-contrast images. They are most often used for discovering and monitoring cancers of the soft tissues such as the brain, pelvis, liver, head, and neck.
You’ll need to take a few steps to prepare for your screening, regardless of which screening method you use.
Recommended reading: Can You Eat Before an MRI?
Both PET and MRI scans can help detect abnormalities in your body before they get worse.
Since PET scans use radiation, MRI scans can be better options for annual screening. And upon your physician’s recommendation, you may go for a PET scan.
First-time visitors can mention “EZRA100” to get $100 off on your first full-body scan.