Whole Body Scans: Not for Everyone

Scanning centers that have opened around the country in recent years offer what sounds like a dream come true: non-invasive diagnostic screening for everything from osteoporosis to cancer to heart disease, all accomplished in one visit through a single, all-encompassing "whole-body" or "full-body" scan. It sounds simple, and the ads stress that the scans are accurate and meaningful.

But major medical associations are wary of this "one scan fits all" approach. Some, including the American Heart Association, the American Cancer Society and the American College of Cardiology, say there is a need for more research into the use of full body scans. The American College of Radiology states that there is insufficient scientific evidence that body scans prolong life and are cost effective.

Kristine S. Spinelli, MD, Medical College of Wisconsin Assistant Professor of Radiology, has looked carefully at the issue of CT whole-body screening. While she agrees that the scans can detect abnormalities, "it turns out that most of these abnormalities, when looked at closely, do not have an effect on the person's health and well-being," she says.

"For instance, they advertise that they're going to find cancer at an early stage. Occasionally that's true. Everyone has anecdotal cases where they found an asymptomatic cancer that was successfully removed before it could spread." That would be a great example for someone who says everyone should go get a full body scan, said Dr. Spinelli. "But for most patients, they're either not going to find anything or they're going to find something that means nothing. More commonly, abnormal results are from benign processes."

Mixed Messages
Making sure that results are benign, however, can itself lead to complications. "One good example is that of the Chairman of Radiology at another institution who had a full body scan," said Dr. Spinelli. "They found two small abnormalities - we call them 'ditzels' - in his lungs, and he had surgery to remove them. They were both benign, but he had complications from the surgery and ended up spending several days in the hospital." The patient went through a serious and ultimately unnecessary procedure with negative health consequences, and he was out $12,000.

Studies are in progress to decide what kinds of whole body screening are truly beneficial and which patients would be most likely to have benefits that outweigh the risks. "Usually when we talk about body imaging we're talking about the abdomen and pelvis," said Dr. Spinelli. "When scanning centers talk about 'whole body' they're usually also including the chest and in some cases even the head. The question is, what are you looking for?"

Electron beam tomography (EBT) is a much-advertised tool of choice at the scanning centers. EBT equipment takes a relatively "fast" picture by using prisms to scatter an X-ray beam that is projected at the body. EBT uses 30% less radiation than conventional computerized tomography (CT) scans.

One of the things that can be found by a full body EBT scan, calcium in the coronary arteries, sometimes means very little in terms of a patient's overall health. This is a hotly debated use of EBT because many people over age 65 have calcium in their arteries, but they don't always have narrowed or blocked arteries because of it. A positive scan for calcium in the coronary arteries can send a mixed message to the patient.

A low calcium score can also be misleading, as arteries can be narrowed or have plaques without being calcified. However, Dr. Spinelli pointed to a recent Mayo Clinic study that said a normal heart scan indicates a very low risk for a major coronary event in the ten years following the scan. The American Heart Association and the American College of Cardiology support the use of full body EBT in the search for calcium only under physician guidance.

Advances in all types of scanning equipment, not just EBT, and the computer systems used to produce and help analyze the images, are moving forward at a rapid pace. EBT is typically used to look at the heart because it is so fast, Dr. Spinelli said.

"Most of the multi-slice CT scanners are becoming so fast that they're almost as fast as electron beam anyway," said Dr. Spinelli. "The only advantage to using electron beam would be for cardiac imaging, because it's so fast it can capture a still image of the beating heart - similar to high-speed photos where you see pictures of a moving helicopter where the blades seem to be fixed in place."

Virtual Diagnostics
Whether at scanning centers or in hospital settings, new technology is opening the door to 'virtual' diagnostic procedures that allow physicians to see what's going on inside a patient without the need for surgical forays that sometimes lead to complications.

For example, Dr. Spinelli described progress she and others have made in developing and applying new methods to colonoscopy. "With virtual colonoscopy, you can scan from diaphragm to below the bladder, from the top of the colon to the bottom of the colon, in twenty seconds," she said, "and these are slices (image sections) that are very thin - one millimeter each."

The traditional use of iodinated contrast injected into the veins to create contrast and produce a better picture is also a topic of interest in the imaging field, Dr. Spinelli noted. "Most people say that if it's an asymptomatic person you should not use contrast," she said, "but then you decrease the sensitivity when looking for lesions. You can get people to argue either way: a radiologist might say you absolutely should use contrast, and another might say you absolutely should not. Using contrast, people can get reactions. It can cause renal problems. So, do you want to use something that will increase the sensitivity but may harm the patient?"

Just a Fad?
Whole-body scans can fairly easily discover kidney stones, kidney masses, abdominal aortic aneurysms, and lung nodules, Dr. Spinelli said, but all of them can be asymptomatic and finding them does not necessarily mean that treatment is warranted.

"Lung nodules are a really sticky area," said Dr. Spinelli, "because a lot of lung nodules are not cancerous. Many people you look at have them, and in terms of tumors of the liver, the pancreas, or some of the other tumors, they're going to be hard to see without the IV contrast. Unless you have the virtual colonoscopy, you're not necessarily going to see colon cancer, although you might if it's a big lesion. And most of the time patients with large lesions are already symptomatic."

Whole-body scanning is often referred to as a "boutique fad" in the news media, in part because the centers are nearly all located near affluent areas. "I would say that is accurate, because if you look there have actually been demographics on a lot of these screening centers asking what it means in the nation as a whole," said Dr. Spinelli. "A lot of these are really going to the well-educated, wealthy patients. These are not going to be set up in inner cities and poor areas. Significantly, plenty more of these places are popping up where people can afford it (out of pocket) and have enough knowledge just to make themselves scared."

"Radiology is very good at answering specific questions. Do I have a kidney stone? Do I have an abdominal aortic aneurysm? It's not very good at saying 'look for anything, find me something.' That's what these screening centers are doing, and I don't think it will help very many people. How many do you scan to find one problem?"

Dan Ullrich
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.