Using Computed Tomography to Evaluate Cystic Fibrosis
Meet the Researcher
Dr. Alan Brody, shown here in front of a CT scanner, has performed recent research showing that CT scanning can be an effective tool to evaluate and monitor CF.
Cystic fibrosis (CF) is an inherited disease that affects nearly 30,000 children and adults in the United States, 80 percent of whom are diagnosed by the age of 3. Medical advances have improved the outlook for those affected by CF, but the disease remains incurable. Early detection of the disease and accurate monitoring of its progression are vital components to prolonged survival for CF patients. At Cincinnati Children's, researcher Alan Brody, MD, is working to show that imaging technology, such as computed tomography (CT) scanning, can be a more effective tool than current testing techniques to evaluate and monitor this disease.
A More Accurate Measure
Dr. Brody, a staff radiologist and chief of thoracic imaging in the Department of Radiology and Medical Imaging at Cincinnati Children's, says that although the first report of CT scanning to monitor CF-related lung disease was published in 1986, interest in the technique has increased recently as the limits of the primary pulmonary function tests -- FEV1 -- have become clear. "At age 6, FEV1 is normal in nearly 90 percent of all CF patients tested," notes Dr. Brody. "We now can show that they're not really normal." Research is showing that pulmonary function tests often underestimate the presence and severity of mild and moderate lung disease. As a result, says Dr. Brody, researchers are asking, "could we use imaging to look at the lungs and more accurately determine the extent of lung disease much earlier in the disease cycle?
"When we started using CT imaging to look at the lungs, we found that CT detected a great deal not detected by FEV1 testing," explains Dr. Brody. "Seventy-five percent of children 6 to 10 years old had clearly damaged lungs despite a normal FEV1. Over a two-year period, CT scanning was shown to be a more sensitive method than pulmonary function tests to detect both structural changes in the lungs and disease progression." Dr. Brody's research shows that the structural changes associated with CF seen with CT scanning often precede the functional changes identified by pulmonary function tests. As a result, CT scanning has the potential to detect CF lung disease sooner. Additionally, says Dr. Brody, research is showing that CT scanning is a more sensitive method than FEV1 in identifying changes in lung disease, thereby providing a much more accurate measure of the disease's progression.
Future Clinical Implications
The far-reaching clinical implications of this research are not yet known. "We're still defining how best to use CT scanning," Dr. Brody explains. "It's not yet clear how best to guide therapy. Currently, it's used mostly when you have a child whose disease is not acting as expected and even the pulmonary function test says things are normal." One obstacle to widespread use is the risk posed by radiation exposure associated with CT scanning. "We have made great strides in reducing radiation exposure, but there is some risk," notes Dr. Brody. "Clearly, we need to balance the benefits of CT scanning with its risks and move slowly into clinical applications."
Though CT scanning is not yet standard, it is clear from the work of Dr. Brody and his fellow researchers that it is a much more accurate and reliable measure than the standard pulmonary function tests. Though much research remains to be done, Dr. Brody envisions a future where CT scanning will not only help to identify and track the progression of CF but can also be used to tailor therapy to an individual patient's lung disease.
Dr. Brody's recent studies have appeared in Journal of Thoracic Imaging (2006;21[1]:14-21) and American Journal of Respiratory and Critical Care Medicine (2005;172:1246-1252).
