Healthy Living

Imaging Tests Explained: What to Expect During a CT Scan, MRI, or Ultrasound

Mar. 3, 2026

Key Takeaways

Medical imaging tests help diagnose injuries and disease without surgery. They are also used to guide treatment and monitor conditions over time.
A CT scan uses X-rays to create detailed cross-sectional images and is often used in emergencies.
An MRI scan uses magnetic fields—not radiation—to capture highly detailed images of soft tissues.
Ultrasound imaging uses sound waves to create real-time images and is commonly used during pregnancy.
Imaging exam preparation depends on the type of test and whether contrast is needed.

Medical imaging tests allow your care team to see inside your body without surgery to diagnose conditions, guide treatment decisions, and monitor your health over time.

CT scans, MRIs, and ultrasounds are safe and painless (beyond a potential needle stick), but it’s natural to be a little nervous—especially if it’s your first time.

The good news: Most imaging tests are quick and done on an outpatient basis, meaning no hospital stay is needed. UR Medicine’s radiologists, in their work as physicians with specialized training in medical imaging, work closely with your providers to ensure you receive the right test at the right time.

Most imaging tests require a referral from a primary care provider or specialist. Your provider will determine which exam is appropriate and coordinate next steps.

Comparing Common Imaging Tests

Feature	CT Scan	MRI	Ultrasound
Radiation	Yes (X-rays)	No	No
Typical Exam Length	5–30 minutes	30–60 minutes	15–30 minutes
Common Uses	Trauma, fractures, internal bleeding	Brain, spine, joints, soft tissues	Pregnancy, abdominal organs, blood flow
Comfort	Short scan, donut-shaped open scanner	Loud knocking noise, modern, more spacious	Noninvasive, handheld probe

What Is a CT Scan?

A CT scan (computed tomography scan), sometimes called a CAT scan, is a type of X-ray that takes detailed pictures of the inside of your body.

Unlike a regular X-ray, which produces a single image, CT imaging creates multiple image “slices” that allow doctors to view organs, bones, and blood vessels in more detail. These scans are fast and highly detailed, and providers often use them when they need answers quickly.

What to Expect

Most CT scans take anywhere from 5 minutes to 30 minutes. During the exam you will lie still on a table as it moves slowly through a large, donut-shaped scanner.

Before the exam, you may be required to drink a contrast liquid and may receive IV contrast during the exam. A technologist will monitor you from a nearby room and can speak with you at any time.

How To Prepare for a CT Scan

Imaging exam preparation may include fasting for several hours or adjusting certain medications. Your care team will give you clear instructions before your visit.

What Is MRI?

An MRI scan (magnetic resonance imaging) uses powerful magnets and radio waves to create detailed images of organs and soft tissues without radiation.

MRI provides detailed images that help doctors diagnose conditions that may not be visible through other types of imaging, such as:

Brain and spinal cord conditions
Joint and muscle injuries
Ligament and tendon damage
Tumors in soft tissues

What to Expect

MRI exams typically last 30 to 60 minutes. And while they are loud, they do not cause any pain. If you’re worried about feeling claustrophobic, know that newer, wide-bore machines provide more space than traditional MRI systems.

Before the exam, you will change into scrubs and be screened for metal implants or devices. Because MRI uses strong magnets, certain implants may not be safe.

Some MRI scans require contrast to better highlight specific tissues, and your provider will prepare you beforehand.

During the scan:

You will lie on a table that slides into a tube-shaped machine.
The machine makes loud knocking sounds. Ear protection is provided.
Staying still is important to produce clear images.

How to Prepare for an MRI

You’ll be contacted by the imaging office to review your medical history and considerations for your upcoming test. Most MRI scans don’t require fasting; however, if a contrast drink is used or the scan involves your abdomen, you may be asked not to eat or drink for a few hours before your test.

What Is an Ultrasound?

Ultrasound imaging uses high-frequency sound waves to create real-time images inside the body. It does not use radiation.

Ultrasounds are commonly used during pregnancy, but they are also important for evaluating:

Abdominal and pelvic organs
Blood flow and vascular conditions
Thyroid and other soft tissues

Because ultrasound provides real-time imaging, it can also help guide certain procedures.

What to Expect During an Ultrasound

Most ultrasound exams take 15 to 30 minutes and are typically painless.

During the test:

A clear gel is applied to the skin.
A handheld device called a transducer is moved over the area being examined.
Images appear instantly on a monitor.

How to Prepare for an Ultrasound

Preparation depends on the type of exam. For example, you may need to fast before an abdominal ultrasound or drink water before a pelvic ultrasound.

Need to Schedule a Test?

UR Medicine offers advanced imaging at convenient locations throughout the region. Our imaging experts work closely with your provider to ensure you receive timely, accurate results.

About Imaging Services