Diagnostic Imaging

The U.S. Food and Drug Administration has a page that explains what computed tomography (CT) imaging is and how it works.

The National Cancer Institute answers common questions about how CT scans work and what a person can expect during the exam. Though the page also discusses tumors and cancer, the information about CT is applicable to anyone.

RadiologyInfo has more in-depth descriptions of specific CT scan studies, such as CT colonography (also known as virtual colonoscopy) and CT angiography, used to look at blood vessels.

The American Cancer Society explains how endoscopy works. Read a lengthy discussion of endoscopy’s role in detecting and treating cancer. Scroll down to the heading “What Does the Procedure Involve?” to find a table listing each type of test and whether any special preparation is needed, including its length and the kind of anesthesia generally used.

Aetna InteliHealth , a consumer health site developed by the insurance company Aetna, offers an overview of endoscopies that explains what to expect through each stage, from preparing for the procedure to post-procedure symptoms.

The North American Society for Pediatric Gastroenterology, Hepatology and Nutrition has a one-page PDF for kids that explains what a colonoscopy is, why a colonoscopy may be prescribed and what to expect before and after the procedure. Another PDF describes an upper endoscopy.

RadiologyInfo has a short video clip that explains, in plain language, what magnetic resonance imaging does.

Marquette General Health System offers an in-depth explanation of how magnetic resonance imaging works, and what it is used for.

MedlinePlus has an illustrated tutorial that explains what an MRI is and what to expect during the procedure. The information is also available in a printable PDF.

RadiologyInfo describes a slightly different type of imaging called functional MR Imaging (fMRI). Learn what fMRI is, how to prepare for the procedure, how fMRI is performed and more.

The American Society of Radiologic Technologists describes the various ways children are kept still during some imaging procedures. Find information on immobilization methods and advice for parents.

The University of Virginia Health System explains what nuclear medicine is and how nuclear medicine scans are performed.

RadiologyInfo describes specific types of nuclear medicine procedures, such as lymphoscintigraphy and cardiac nuclear medicine.

Cleveland Clinic explains how nuclear imaging is different from other radiologic tests, and describes what to expect before, during and after the test.

The Society of Nuclear Medicine has a short glossary of words and acronyms commonly used in nuclear medicine.

RadiologyInfo takes parents step-by-step through what their child can expect during a nuclear medicine study.

MedlinePlus has an illustrated overview of ultrasound that covers how they work and what patients can expect during them. The presentation is also available in a printable PDF.

MedicalPhysicsWeb has an interview with Stephen Smith, a researcher who helped develop the three-dimensional ultrasound technology. Smith talks about how the technology works and its advantages.

National Geographic News spoke with Professor Stuart Campbell, a leading obstetrician, on four-dimensional ultrasound imagery. Learn how the 4D scans work, their benefits and more.

RadiologyInfo explains what happens during an ultrasound. The site also has more detailed information about ultrasounds on specific parts of the body.

Medem explains what X-rays are, why they are performed and how X-ray examinations are provided.

RadiologyInfo has detailed explanations of the different types of X-Ray studies, such as bone densitometry, mammography, arthrography and others.

The U.S. Food and Drug Administration discusses X-rays and pregnancy. Learn the risks posed by X-ray during pregnancy, and why it’s important to tell your doctor if you’re pregnant or think you might be.