MRI vs. Ultrasound: Which is Better?

The world of diagnostic imaging can be very hazy (though hopefully your images are not). There’s of buzzwords that get thrown around, and you might feel lost in the shuffle. MRI? PET? CT? Ultrasound? X-ray? Contrast? Open? Closed? What does it all mean?

Today, we hope to help demystify the difference between an MRI and an ultrasound.

If you’re wondering, do I need an MRI? Do I need an ultrasound? Luckily, your doctor will usually tell you exactly what you need, so don’t stress over it too much. However, it’s always a good idea to stay informed, so if you want to know why you’re getting that particular test done, take a look at the article below.

What is an MRI?

An MRI is magnetic resonance imaging, and in very simple terms, it takes a picture of what’s happening inside your body. The machines are usually large and can be either open (where you stand under what seems like a giant plate) or closed (where you would usually lie down inside the enclosed machine). The machine uses magnets to activate the hydrogen atoms in your body which the machine’s radio waves can read to produce a picture.

What is an Ultrasound?

Ultrasounds (sometimes called sonography) uses sound waves instead of radio waves to produce a picture within your body. This is typically done using a specific wand outside your body (though some internal sonograms are done) instead of a large, full-body machine. Because of this, the ultrasound produces a real-time look into the body while an MRI will produce a photo after compiling all the different cross-sections.

What’s the Difference?

Again, ultrasounds create a direct look into the body. If you think about a pregnant woman hearing her unborn child’s heartbeat for the first time. That’s happening in that moment, right then. An MRI takes many images to create the full scan that you see doctors examining later, so there’s a little bit of a wait for it.

The real-time imaging of the ultrasound does have it’s advantages as well. It’s faster and cheaper, and the scan happens with the patient there and conscious. The technician can interact with the patient and guide the test if necessary.

However, though it takes longer, an MRI has more capabilities than an ultrasound, like an MRI can look through a bone while an ultrasound cannot. Remember, this capability is not necessary for all procedures, so don’t assume an MRI is better. In fact, it’s much more expensive and time-consuming. However, it does offer a full-body, elaborate image of what’s going on, so it might be necessary for your condition (or what your doctor wants to explore) to get the more in-depth imaging.

If you have questions about why your doctor chose what they chose, ask them. They should be able to easily explain their choice. They might be trying to save you money or they might want faster results. They might also have other concerns they want to explore or precautions they want to take. This is information you are entitled to, so don’t be afraid to ask.

By Joanna Hynes