Medical Imaging: Types of Imaging

A bone scan is a nuclear imaging test that helps diagnose and track several types of bone disease.

This type of imaging uses the most amount of radiation compared to the others on average, per exam. It is essentially a radiographic x-ray camera that rotates around the patient very rapidly, taking pictures from every angle possible and using advanced software to reconstruct three dimensional images. The reason they are commonly used is their superb ability to provide high contrast images that enable a radiologist to see things that are usually very difficult to see using other forms of imaging. At Children's Mercy, all of our CT scanners use state of the art technology that employ a multitude of advanced techniques to minimize doses to children.

This type of imaging is used when we want to observe movement inside the body. For example, an expert care provider may want to examine a child's pharyngeal disorder by observing the swallowing of a contrast agent. Or an interventional radiologist may need to ensure the proper and careful placement of a peripherally inserted catheter during a procedure. This type of imaging works just like an ordinary x-ray, but multiple exposures (pictures) are taken, instead of just one. In this sense, a fluoroscopic machine is very similar to a webcam or video camera. Depending on how long the exam takes, fluoroscopic machines can use very little to moderate amounts of radiation. Fortunately, there are many techniques that we use to minimize the risks to our little patients.

Magnetic Resonance Imaging (MRI) is a safe and painless test that uses a powerful magnet and FM radio waves to produce detailed pictures of the body’s soft tissue organs and other structures. It is extremely useful for evaluating the brain, spine, heart, liver, blood vessels, and joints throughout the body. These images can help pinpoint many problems in the body that can’t be seen with other forms of medical imaging.

Whereas fluoroscopic and radiographic x-ray imaging provide us information about what's inside the body, nuclear medicine imaging tells us what is happening inside the body. For example, a PET scanner or a SPECT study can tell us if a kidney or liver is functioning as it should be. To accomplish this, we inject a very tiny amount of radioactive tracer into the patient's body (such as for example glucose that's been labeled with a radioactive molecule), and observe how the glucose is distributed inside the body inside various organs. This provides us with a very powerful tool for seeing the physiology and metabolism of our patients. The radioactive tracers usually decay and leave the body through normal peeing of your child within 24 hours. At Children's Mercy, the doses we give to our little patients are sometimes 1/10th of what an adult is given, in order to minimize the radiation risks.

X-rays can be thought of as a form of high energy light. Their energy is so high that we cannot see them with our eyes. Their high energy however, enables them to penetrate through the body and illuminate the internal structures that we do not normally see with the naked eye. An x-ray machine therefore, in this sense, works just like a photographic camera. Because the x-ray shutter is open for a very short time, radiation from this type of imaging is usually very minimal and is comparable to the amount of radiation you receive from your natural surroundings at home.

A renal scan provides pictures of your child's kidneys to see how the kidneys are working, including size, shape, position, and urinary flow.

Ultrasound uses high frequency sound waves to obtain an image of inside the body.

A voiding cystourethrogram (VCUG) is an x-ray examination of your child's bladder and urinary tract that uses a special form of x-ray called fluoroscopy and a contrast material.