What Is an MRI and How It Works — A Simple Guide for Patients

At Independent Physicians Medical Center (IPMC) in Northeast Philadelphia, we offer advanced MRI imaging in a comfortable outpatient setting, making it easier for you and your doctor to get accurate answers without the stress of a hospital visit.

What Is an MRI?

An MRI scan is a medical imaging test that uses strong magnets, radio waves, and a computer to create highly detailed images of the inside of your body — including organs, soft tissues, blood vessels, and bones — without using radiation.

Unlike a standard X-ray or CT scan, MRI doesn’t involve ionizing radiation, making it a safer option for repeated imaging when needed.

How Does MRI Work?

When you undergo an MRI:

• You lie on a cushioned table that slides into a large, tube-shaped scanner.
• The scanner creates a strong magnetic field around your body.
• Radio waves are sent through your body, causing atoms in your tissues to send back signals.
• These signals are captured and processed by a computer to create detailed cross-sectional images.

Different types of tissues — such as muscle, fat, organs, and tumors — respond differently to the magnetic field, allowing radiologists to distinguish between normal and abnormal structures.

Why Doctors Order MRI Scans

MRI scans are often used when doctors need a close look at soft tissues or internal structures that aren’t easily seen with other imaging tests. They can help diagnose and evaluate a variety of conditions, such as:

• Brain and spinal cord issues
• Joint and muscle injuries
• Heart and vascular conditions
• Tumors and cancers
• Organs in the abdomen and pelvis
• Infections or inflammation

Because MRI provides such clear images, it can be especially useful in cases where symptoms are unclear or more detail is needed before treatment decisions are made.

What to Expect During the Test

An MRI scan is noninvasive and painless. Most patients stay awake during the test, though they must lie still. Scans typically last 20 to 60 minutes, depending on the area being examined.

Some MRI exams may use a contrast agent — a special dye given through an IV that helps highlight certain tissues or blood vessels more clearly on the images. Your doctor will let you know if contrast is needed.

The machine may make loud clicking or tapping noises during the scan, so you may be offered ear protection to make the experience more comfortable.

Benefits of an MRI Scan

MRI offers several advantages over other imaging methods:

• No radiation exposure
• Excellent soft tissue contrast
• Detailed 3D images
• Helpful for complex diagnoses
• Can monitor changes over time

This makes MRI a valuable tool for diagnosing conditions ranging from neurological disorders to joint injuries and heart disease