A generation or so ago, if you had a health concern, your doctor likely made a diagnosis with the information gleaned from a physical exam and your medical history.
Computerized tomography (CT), introduced in the 1970s, and magnetic resonance imaging (MRI), which appeared in the 1980s, changed all that.
“Imaging is integral. It really is in the center of everything,” says Rihan Khan, MD, chief of neuroradiology at Banner – University Medical Center. “There’s not a service in the hospital it doesn’t affect, from surgery to OB/GYN to pediatrics to all of the medical subspecialties.”
Although there’s some overlap in what appears on CT and MRI scans, certain situations can make one or the other a better choice.
These scans use a computer to meld multiple X-ray images. CT scans are fast, making them the go-to option in trauma cases. CT scans also show great bone detail, making them good for identifying fractures. When contrast dye is given, it enhances the detection of many lesions. Although there is a small amount of radiation with the scan, CT is considered a very safe exam when performed correctly and used appropriately.
MRI uses a large magnet to temporarily align molecules in the body and uses radio waves instead of X-rays to create images. MRI is very safe, and there’s no radiation exposure. MRI is superior at imaging soft tissues, and although these tests take longer than CT scans, they’re getting faster all the time. Contrast may be given to enhance the detection of lesions, which is a different type of contrast than that used for CT scans.
This version of an MRI doesn’t enclose patients in a tube, so it can be a good choice for people who are claustrophobic and for people who are too big to fit in a closed MRI scanner. However, Dr. Khan prefers the closed scanner whenever possible because it generally provides better image quality.
If your doctor orders a CT or MRI scan, you’ll likely be able to schedule an appointment within a week, either at the hospital or an outpatient imaging center. An MRI scan may take 20 to 35 minutes, depending on the area being scanned, and a CT scan typically takes just seconds.
Along with CT and MRI, other imaging is useful in viewing certain areas of the body.
This tried-and-true study is great for identifying abnormalities such as fractures, arthritis, lung masses, signs of trauma and bowel obstruction.
This technology, which uses sound waves to produce images, is good for imaging the liver, spleen, gallbladder, kidneys, bladder, thyroid, lymph nodes, uterus, ovaries and testicles, and may be most well-known for its images of unborn babies.
This study, combining positron emission tomography (PET) with CT, can help track the spread of cancer throughout the body by monitoring the metabolic activity of both normal and cancerous tissue.
This form of X-ray technology, dual-energy X-ray absorptiometry (DXA), is used to measure bone density to help determine bone health.
New technological developments are bringing higher image quality, better resolution and more detail to scans. Banner – University Medical Center has invested in new ultrasound, CT, MRI and PET CT equipment in recent years to bring top-quality, cutting-edge scanners to its patients.