by Monica Zangwill, MD, MPH
At 58 years old, Bill Z. worried he was running on borrowed time. His father died of early heart disease. His mother died of cancer. Although Bill felt well, he wondered if his body harbored a killer that could rear up at any time. He'd read about computed tomography (CT) scans that screen your whole body for disease and he wondered, "Does it really work?"
Like most things in medicine, the answer to Bill's question is yes and no.
What can a CT scan tell you?
A CT scan machine uses x-rays to produce three-dimensional computer images of the heart, lungs, intestines, and other vital organs inside the body. From these pictures, a doctor can easily find a tumor or other irregularity. In fact, doctors commonly use CT scans to look for suspected problems in a sick person. But using CT scans to screen for abnormalities in a healthy person is new.
Promising research
Recent research suggests much promise for the use of CT scans to screen specific body areas—such as the colon, lungs, and heart—for disease. Amin Chaoui, MD, a radiologist at Boston University School of Medicine, says: "Screening for colonic polyps is a very good test. It has proven to be very effective."
Likewise, studies show that screening specifically for calcium around the heart is an accurate way to pinpoint people who will likely have a heart attack in the future. On the other hand, although scans of the lungs can effectively find tumors, physicians don't know yet if this early detection saves lives.
What about total body scanning?
Questions arise among the experts when CTs are used in a scattershot way to scan the whole body for disease rather than specific areas. Paolo Raggi, MD, a cardiologist at Tulane University School of Medicine, believes that CT scanning is valuable in looking for heart disease in someone without symptoms, but worries about whole body scanning. "I am not against finding things so you can approach it, but what if you find a lot of unnecessary [things]?" he asks. "What are we going to do with it?"
What Dr. Raggi and others worry about is finding a high number of false positives and false negatives. False positives occur when a scan of a healthy person's body finds something that looks suspicious for disease but turns out on further exploration to be benign.
False negatives occur when something that appears normal at the time of the test actually hides disease that will manifest in the near future. Experts argue that currently there is just not enough experience with total body scanning to say its benefits clearly outweigh its risks of false results.
Controversy continues
Other physicians argue that since we have the technology of the CT scan why not use it. Max Rosen, MD, assistant professor of radiology at Harvard Medical School says, "The best uses [of total body CT scan screening] are to give patients intelligent information about their health status that they can use to make decisions about future medical care or lifestyle choices." He feels as long as the risks and benefits are clearly discussed, total body CT scan screening can only add to the overall knowledge of a person's health.
Dr. Rosen also dispels the severity of the radiation risk saying that the radiation exposure from most CT machines is equal to the radiation you receive from riding across the country on an airplane.
Still a new concept
Currently, several radiologic centers offer total body CT scans. The cost for a total body CT scan ranges from 300 to 1200 dollars depending on where it's done. The cost is not covered by health insurance.
Also, since total body scanning is new, no one knows how often it should be done. For someone with risk factors, like a family history of heart disease, repeated screenings over time may be helpful, but again the answer is unknown.
As for Bill Z., he decided to try it. He had a CT scan to look for calcium in his heart vessels. The results showed calcium and some masses in the liver. After further tests, the liver masses turned out to be okay, but the calcium suggests he is at significant risk for heart disease. Still, he's happy he had the test. "The results helped tip the scales for me to lose weight and get my blood pressure down," he says.