Photo by MART PRODUCTION
“May nakita tayong tumor sa utak mo…” said the old man in white gown in your favorite telenovela.
So how did he know? He didn’t crack the skull to look inside, did he?
Well, in real life, the real doctor has probably read the radiologist’s report and seen the MRI scan results.
MRI stands for “Magnetic Resonance Imaging.”
It is a painless, non-invasive imaging tool used by doctors to help diagnose a wide array of conditions—like brain injury, cancer, stroke, blood vessel blockages, and kidney abnormalities.
MRI scans work well in imaging soft tissues and organs. So if you want a 3-D image of what your organs look like inside, you get inside one of these MRI machines.
How Does It Work?
At first, MRI might sound complicated, but the idea is pretty simple. It all comes down to magnets, radio waves, and the water inside the body.
Step 1: The Power of Magnets
The body is made up mostly of water, and water molecules contain hydrogen atoms. These atoms behave like tiny spinning tops, each with a weak magnetic field.
When you enter an MRI machine, a giant magnet inside the machine aligns all these hydrogen atoms in the same direction—like tiny compass needles pointing north. The atoms get in formation like a battalion of soldiers awaiting inspection.
This is the first step in creating an image.
Step 2: Come the Radio Waves
Once the hydrogen atoms are lined up, the MRI machine sends out pulses of radio waves. These waves knock the atoms out of alignment.
But when the radio waves stop, the atoms snap back into place.
Step 3: Capturing the Signal
As the atoms return to their normal position, they send out signals, like tiny radio stations broadcasting their location. The MRI machine picks up these signals and records them.
Step 4: Creating the Image
A powerful computer analyzes all these signals and turns them into a highly detailed image of the inside of your body. Muscles, fat, and bones send different signals, which is why MRI images are so clear.
Think of it like this:
The magnet organizes the atoms.
The radio waves give them a little push.
The computer listens to their response and turns it into a picture.
The good thing about MRI machines, besides the clarity of the scans, is the fact that they don’t use radiation to generate the image.
Unlike X-rays or CT scans, which use radiation, MRI uses a strong magnet and radio waves to create images—making it one of the safest and most effective ways to check for injuries and diseases.
X-rays and CT scans may be great for seeing bones, but they use radiation. Too much of it is harmful over time.
MRI machines look into soft tissues like the brain, heart, and muscles—and they don’t expose you to radiation.
Contrast Dyes During MRI Scans
Sometimes, doctors need even clearer images during an MRI scan. That’s where contrast dyes come in. These are special substances that highlight certain areas of the body, making abnormalities or specific structures easier to see.
What Is a Contrast Dye?
An MRI contrast dye is a liquid that helps improve the clarity of MRI images. The most commonly used contrast agent is gadolinium-based dye. Gadolinium is a metal that reacts with the magnetic field, making certain tissues stand out in the final image.
How Is Contrast Dye Given?
Most of the time, contrast dye is injected into a vein in your arm through an IV line. The process is quick and usually painless, though you might feel a cold sensation or mild warmth as the dye enters your bloodstream.
In rare cases, contrast can also be taken orally (by drinking it) if doctors need to examine the digestive system.
Photo by engin akyurt on Unsplash
What Does the Contrast Dye Do?
Once injected, the contrast dye travels through your bloodstream and collects in certain tissues or organs, making them appear brighter on MRI images. It helps doctors:
See blood vessels more clearly (useful for detecting blockages, aneurysms, or tumors).
Spot inflammation, infections, or abnormal tissue growth (such as tumors or multiple sclerosis plaques).
Highlight the brain and spinal cord (helpful in diagnosing strokes or nerve disorders).
The dye doesn’t permanently stain or change anything in your body—it just makes things more visible during the scan.
The dye leaves the body through urine.
What It's Like To Be Inside An MRI Machine?
Photo by MART PRODUCTION
If you’ve never had an MRI before, here’s what to expect:
Step 1: Getting Ready
You do not have to go on special diets or restrict your daily activities before coming in for a scan UNLESS your doctor gave you special instructions to do so.
You’ll need to remove any metal objects, like jewelry, glasses, or belts, since the MRI magnet is very strong. The magnetic field created by the machine is so strong it is said that it can pull a car.
Imagine what that would do to your metallic earrings.
You should inform your doctor if you have implants like pacemakers, insulin pumps, stents, or even dental implants. Inform the doctor if you have a long-standing bullet or any piece of metal stuck or placed inside your body.
You’ll wear a hospital gown and might be given earplugs or headphones since the machine is loud.
When a contrast dye is used, this will be injected into your arm before the scan.
Step 2: Inside the MRI Machine
The MRI machine is a large cylindrical apparatus. You’ll lie down on a table, which slides into a large, tube-shaped machine.
The whole process is painless, but the machine will start making loud knocking or buzzing noises. This happens when the radio waves are being sent.
You must stay very still so the images come out clear. Any movement might distort results and affect image quality. (Think of it like posing for a camera.)
The technologist will be in another room to man the controls. But there are speakers and microphones inside so you can communicate. You can let the technologist know if you have any problems during the procedure.
Depending on what part of your body is being scanned, the test can take anywhere from 15 minutes to 90 minutes.
Photo by MART PRODUCTION
Common Concerns
Claustrophobia: Some people feel uncomfortable inside the machine. If you’re worried, ask your doctor about open MRI machines or mild sedatives.
Noise: It’s loud, but earplugs or headphones could help.
Safety: MRI is very safe and painless. The discomfort may be in trying to stay still for a long time.
Step 3: After the Scan
There are usually no side effects. Most patients can go home immediately after the scan and resume normal activities.
Photo by Anna Shvets
If you had contrast dye, you’ll be asked to drink more water to help flush it out faster. You might feel a little warm or have a weird taste in your mouth for a short time as a side effect of the dye.
A radiologist will read/study the images and come up with a report, which he/she will send to your doctor.
After a few days or a week, your doctor will explain the results and discuss if there’s anything to do next. Some conditions may need multiple MRIs over time to track changes. Your doctor will tell you if you need more scans in the future.
Again, the good thing about MRIs is that they don’t use radiation, so they are relatively safe, painless, and non-invasive.
That said, may you never meet one.
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