Imaging 101

What are the differences among the various medical imaging exams?

By Deborah Jeanne Sergeant

 

Imaging offers providers a glimpse inside our bodies without opening up the skin. But what are the differences among the various types of exams?

 

X-Ray

Efficient and painless, X-rays are typically used to get a good look at the bones and soft tissues. Patients may lie, stand or sit near the equipment for about 15 minutes. Because radiation is used, providers will not be present in the room. Repeated exposure such as X-raying patients daily could cumulatively endanger providers. The patient may wear a lead covering to protect areas that do not need to be X-rayed, such as the apron available at dentist’s offices. Typically, X-rays focus on the area in question. Providers note X-rays in their patients’ charts to ensure that they do not receive unnecessary X-rays. Any imaging involving X-rays is not recommended for pregnant women.

 

CT Scan

A computer uses numerous X-ray images to create a 3D style image with the CT scan. Providers can look at bones, soft tissues, tumors and clots. Some of these procedures require patients to have a contrasting dye in their system, either through an IV or by drinking it. Patients lie on a table in a room separated from the technician. The table slides into a large tube and then the X-ray equipment moves around the patient. The whole process takes about 15 minutes. Like standard X-rays, providers are not in the room to prevent cumulative radiation damage.

 

MRI

MRIs use magnets, radio waves and a computer to take a look at organs and soft tissues. Similar to CT scans, patients lie on a table that moves into the MRI equipment, which can be noisy at times. The scan can take up to an hour to complete. Providers can use MRIs to diagnose conditions such as aneurysms, multiple sclerosis, strokes, spinal cord problems, tumors and injuries to the joints or tendons.

 

Fluoroscopy

To watch movement inside the body in real time, providers may use fluoroscopy. This type of imaging uses pulses of X-ray beams along with dye to help diagnose heart or intestinal diseases, guide surgery or injections or in orthopedics. Regular X-rays are like still photos, but fluoroscopy is more like videography. Providers can look in organs, joints, muscles and bones.

 

Ultrasound

As the name denotes, ultrasound uses sound waves to develop images (sonograms) of organs within the body. It’s commonplace to use ultrasound to detect fetal development in pregnant women. The technician lubricates the skin with gel and uses a handheld probe against the skin with firm pressure. Ultrasound procedures can take 30 to 60 minutes, depending upon the reason for the ultrasound, which can include diagnosing a plethora of diseases, blood flow problems, genital issues, tumors and more. Ultrasound can also help guide providers taking a biopsy.

 

PETScan

PET scans (positron emission tomography) use a safe, radioactive tracer to help providers find diseased cells, typically for cancer, heart disease and conditions affecting the brain. Like the CT scan, the patient lies on a table that passes into the examination equipment. The radiotracer helps create images of the diseased cells because they absorb larger amounts of the material than healthy cells. The scan can take up to two hours. Some providers may use both the PET and MRI at the same time to make high contrast images, typically for tracking cancers in soft tissue areas.