How Doctors Choose Between X-Rays and MRI Scans

Most patients get why they’re visiting a diagnostic imaging center; their health care teams want a closer look at their insides — preferably without invasive surgery. But not everyone is clear on why their doctors choose the type of imaging they do. What’s the difference between an X-ray and an MRI scan? Which one is “best?”

Well, no one imaging modality is superior to the others. They’re all useful in their own ways. That’s why radiologists study multiple technologies and excel in reading results from all of them. If you’re curious about the differences between these two major types of diagnostic imaging, start with this intro.

X-Ray Imaging

If you’ve only ever had one type of imaging before, it was probably an X-ray. X-ray technology is among the oldest noninvasive techniques scientists have used to peer inside the human body. It remains the most common.

How X-Rays Work – X-rays are essentially beams of electromagnetic radiation. As they pass through the body and internal tissues, different parts of the body absorb different quantities of radiation. The remaining radiation shines through the body to strike a detector medium (such as film) on the other side.

Spaces in which a lot of radiation shine through show up dark. Behind tissues that absorb a lot of radiation, though, the image appears bright. Bones can absorb a lot of the radiation, so they show up brightest on the resulting images.

Why Doctors Order X-Rays – Given the clarity of bone tissue in a standard X-ray image, it’s no surprise that doctors often choose X-ray imaging to diagnose broken and damaged bones. They also use this modality to image the lungs, blood vessels, stomach (when looking for swallowed objects, for instance), and breasts (which is called mammography).

MRI Scans

Magnetic Resonance Imaging, or MRI, has the great advantage that it doesn’t expose patients to any ionizing radiation at all. But that doesn’t mean MRI scans are the best for every diagnostic scenario.

How MRI Scans Work – An MRI machine starts by creating a powerful magnetic field around (and within) the patient’s body. This causes hydrogen protons in the body to begin spinning in the same direction — a uniform rotational axis, you might say.

Once these protons snap into equilibrium, the technologist triggers a blast of radio waves through the body. The radiofrequency field knocks the protons’ rotational axes out of whack. Eventually, the protons return to equilibrium, but here’s the kicker — they do so at different rates in different types of tissues. Plus, while they’re returning to equilibrium, they emit a tiny but measurable bit of energy. The scanner picks these signals up, translates them into an image, and there you have it: a picture of the body at work.

Why Doctors Order MRI Scans – MRI scans are very, very good at displaying images of soft tissues. They’re very clear on what in these tissues is normal, and what is abnormal. For that reason, doctors prefer MRI scans for looking closely at organs, tendons, and blood vessels.

The important thing to remember is that your general practitioner, your radiologist, and the other professionals on your health care team will order the exam that helps you most. They might even order X-rays and MRI scans.

When you’re ready to schedule an X-ray, an MRI scan, or any other imaging modality, call at 888-322-7785 for a convenient appointment at an affordable price.

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