April 2001 Volume 4 Issue 2
TELEMED-E-ZINE
A Brief Discussion Of Cardiac & Full-Body Scanning
With the introduction of new technologies, performing computer tomography (CT) imaging has become faster when using the latest specialized equipment and software. Ultrafast CT entered widespread public awareness in 1999 and 2000. In an effort to remedy the "reactive" nature of medicine, Dr. Harvey Eisenberg (HealthView; Newport Beach CA) advanced the concept of applying more sophisticated software to better capture images of the heart and lungs. A medical journal article published in late 1998 indicated that electronic beam CT could potentially be valuable to evaluate coronary artery stenosis and occlusions, especially since non-invasive imaging would be preferable to the estimated 1.0 million angiography procedures that are performed in the United States annually.
Technology Development
In 1999, a proprietary system was developed and put into use at HealthView to screen for coronary artery and heart disease. A competing technology from Imatron (South San Francisco CA) was also being pursued. Both attempt to adapt conventional computed tomography to enable more rapid acquisition of images to essentially provide stop-action views of the heart.
Just a few years ago, there was a limited number of fast CT imaging systems in operation. Recently, Imatron's patented electron beam tomography (EBT) technology has been commonly referenced in the mainstream media. In general terms, the system sends a beam of x-rays through the patient to a set of detectors, creating cross-sectional images for analysis.
More data was accumulating regarding the importance of the kind of plaque that is found in arteries. The number of installed systems increased significantly in 2000, with several media reports referring to ultrafast scanning locations in Southern California and Chicago during the early part of the year.
Payment Controversies
As reported in an article from August 2000, most health insurers were not paying for fast CT testing. With heavy marketing and promotion targeting the general public, reimbursement is not a barrier because patients are willing to pay for the scans out-of-pocket. Without the third-party controls normally encountered with the delivery of health care services, there are actually major revenues benefits: Immediate payment (often by credit card), lack of certification requirements, and limited amounts of paperwork to process. Another interesting development associated with fast CT scanning is an increase in cardiac catheterization volumes. On the downside, the hype has created a difficult environment in which to pursue scientific assessments of the value of this technology.
Many scanning centers use a direct-to-consumer marketing approach that has generated concerns about profit motives and unnecessary use. Another concern is that a negative scan does not rule out the possibility that a person may still suffer from a heart attack within a year or two of being tested. Those wanting to err on the side of caution hope that a study being conducted by the National Institutes Of Health (NIH; Washington DC) will provide more definitive answers when completed in 2005. For example, there are still questions about how much calcium presents a risk for heart disease.
In the meantime, preliminary studies suggest some ranges with which to evaluate electron beam computed tomography (EBCT) scores. The ongoing uncertainty regarding interpretation, however, supported decisions made by insurers such as Blue Cross Blue Shield Of Massachusetts (Rockland) to not reimburse for EBCT in April 2000. In July 2000, a report released by the American College Of Cardiology (ACC; Bethesda MD) and the American Heart Association (AHA; Dallas TX ) acknowledged the potential advantages for selected groups of patients but stopped short of recommendations for use with the general public.
Research Highlights
On the clinical side, a peer-reviewed EBT study of 1,764 patients was published in the February 2001 by the ACC, with findings that supported use of EBT as a "filter" for coronary artery scanning in symptomatic patients. Results from another study conducted at Walter Reed Army Medical Center (Washington DC) were also announced in early March at the AHA's annual conference. EBT was considered to be useful in identifying patients who appeared to be healthy (athletic, low cholesterol, non-diabetic, non-smokers, etc.) but were at risk for coronary artery disease that hadn't been detected by other means. One of the most significant findings was the wide range in calcium scores, prompting one research to be more aggressive with treatment for patients with a score of 40 or over. Toward the end of March, additional presentations at the ACC's Scientific Sessions meeting also focused on EBT with respect to predictive accuracy and sensitivity.
