The Scoop on Scans

What's the difference between CT, MRI and others?

To diagnose his lung cancer, John Hornick, 69, of Beaver Meadows benefitted from both a CT scan (which revealed a small tumor on his left lung) and a PET scan (which confirmed the tumor was cancerous). Those scans caught Hornick's cancer at an early and treatable stage.

CT and PET are among the many wonderful tools that help us diagnose disease faster. The earlier we can find conditions like lung cancer or coronary artery disease, the better the chances for recovery.

Here is a guide to many common imaging procedures and how they help you:

X-Ray

Is your arm fractured? An X-ray will tell the tale. The most basic of imaging techniques, it uses radiation to visualize bones and soft tissue. X-rays also can help diagnose lung conditions (such as pneumonia), heart abnormalities (such as fluid around the heart) or, in the case of mammography, breast cancer.

CT Scan

Is a tumor causing your breathing problems? A CT (computed tomography) scan will let you know. It uses radiation and computer technology to produce two-dimensional images, which allow doctors to see organs in great detail. CT scans are helpful in diagnosing tumors, evaluating abdominal pain and internal injuries, in both the head and the body. The CT scan produces images in "slices," and the more slices, the more detailed the image. Lehigh Valley Hospital and Health Network uses a 64-slice CT scanner to produce very high-quality images. The speed of the 64 slice CT scanner allows imaging of moving structures and flowing blood, providing detailed images of the heart and vascular system. The thinner slices that can be obtained with this technology also allow doctors to perform 3 dimensional images of various body parts, such as the heart and pelvis.

PET Scan

Is your tumor cancerous? You can get the answer from a PET (positron emission tomography) scan. It is a type of nuclear medicine procedure. This means you will receive an intravenous injection with a tiny (and safe) amount of a radioactive substance about 30-60 minutes prior to the scan. PET gives doctors information about the function of a tumor or organ, so it can predict, for example, if a tumor is cancerous or has spread, or if blood flow to the heart is compromised. It also is useful for diagnosing conditions like dementia or Parkinson's disease. At Lehigh Valley Hospital and Health Network we use a dual PET/CT scanner. This gives doctors the same information as a PET, with the addition of a CT scan performed simultaneously. Because both scans are done at the same time, it allows more accurate diagnosis than either PET or CT performed alone.

MRI

What is causing your back pain? An MRI (magnetic resonance imaging) may offer a clue. It uses magnets (not radiation) to form images of soft tissue. It allows detailed imaging of the spine and surrounding soft tissues, discs, nerves, muscles and ligaments. MRI is helpful in diagnosing back or neck pain, evaluating brain tumors, diagnosing certain types of cancer and planning care after a stroke. It is may also used to evaluate the structure and function of your heart.

Ultrasound

Ultrasound uses sound waves to create images of the body. It can be used to evaluate for diseases of the gallbladder, liver, and kidneys. Ultrasound is also used during pregnancy, allowing doctors to monitor development of the fetus. A specialized ultrasound, called an echocardiogram, allows doctors to evaluate the structure and function of the heart.

Nuclear Medicine

Is there a problem with your thyroid? A nuclear medicine test will give you clues. Much like a PET scan, nuclear medicine scans use a tiny (and safe) amount of a radioactive substance to create an image. Nuclear medicine is often used to diagnose thyroid problems, spread of cancer, and heart disease.

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