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A spate of publicity in the general press has increased the public’s awareness of and demand for whole-body ultrafast CT screening technology for a wide variety of maladies. But industry and professional representatives working with this technology
A spate of publicity in the general press has increased the publics awareness of and demand for whole-body ultrafast CT screening technology for a wide variety of maladies. But industry and professional representatives working with this technology warn that the established benefits of screening in certain applications must be balanced with caution in less well-tested areas.
Much commotion was raised concerning the use of EBCT technology for whole-body screening following an August article in USA Today. The reporter, Bob Davis, traveled to the HealthView screening center in Newport Beach, CA, which is run by radiologist Dr. Harvey Eisenberg. After being screened, Davis was found to have a weakened artery wall, which could result in a future aneurysm.
Promotional material distributed by HealthView describes screening with EBCT as a means to simultaneously detect heart disease, cancer, emphysema, aneurysms, osteoporosis, and ovarian and prostate disease.
Eisenberg did not return SCAN telephone calls asking for comment.
While advanced spiral CT scanning technology is sometimes used for screening purposes, attention has been focused mostly on the expanded use of the electron beam computed tomography (EBCT) technology developed by Imatron of South San Francisco, CA.
EBCT has proved itself in the area of coronary artery calcium screening, which is an indication of coronary artery disease. In first-stage testing, without contrast, EBCT is used to diagnose the presence and degree of atherosclerosis, according to S. Lewis Meyer, Imatrons CEO. Further testing with contrast can demonstrate coronary artery stenoses.
In addition, a number of clinical papers point to the use of EBCT in early lung lesion detection. EBCT may also prove useful in screening for colon cancer, although here the advantage over other high-speed CT technologies is less marked.
Imatron sees the unique value of its cross-sectional imaging technology principally in freezing cardiac motion and cardiac-motion-generated image degradation in the lungs, Meyer said. The advantages are less clear in other areas, such as kidney and liver cancer screening.
I would like to know the negative predictive value; what is the significance of a normal scan, Meyer said. I can tell you exactly what that is when it comes to coronary artery disease. But there hasnt been that type of data in other areas. I think you will see that type of clinical work when it comes to diagnosing stage I lung cancer.
Interest in EBCT screening may be boosting demand for the Imatron technology. The vendor reported this month that it has sold its first mobile EBCT system, the sixth unit overall sold so far in the companys third quarter (end September).
Following the USA Today article, calls for screening services began to flood other providers, such as Vital Imaging/HealthScan of San Diego. The center began receiving 15 to 20 calls an hour from prospective screening patients, said Gerald Friede, president and COO.
A lot of them were looking for the full treatment, Friede said. In this case, we explained what the test does do and doesnt do.
Vital Imaging screens for problems in the heart, does some lung cancer work, and performs virtual colonoscopies in conjunction with the University of California, San Diego, Friede said.
To maintain that you are screening for cancer, other than, potentially, lung cancer, is really taking things further than they should be taken, he said. We tell (patients) that, as we scan through the body, the other organs will get looked at. There is a possibility that we will find an incidental cancer. If we do, that is fortunate, but, if we dont find one, that doesnt mean they dont have cancer.
When EBCT technology is employed to scan appropriately at-risk patients, it can be a useful screening tool in the heart, said Dr. Daniel Berman, chief of cardiac imaging at Cedars-Sinai Medical Center in Los Angeles.
We wouldnt screen 20-year-olds, he said. People who are at risk for coronary artery disease are effectively screened.
The problem in screening for serious illnesses outside of the chest, Berman said, is that there is a need to balance the chance of positive results leading to beneficial therapy with the possibility of false-negative results providing a faulty sense of confidence, or of finding disease processes that dont indicate a need for treatment.
We have much more information on the chest for lung (screening) and in the heart for coronary arteries to justify screening and to help identify which patients need to be screened, he said.
A statement on the benefits of calcium screening was issued recently by the American Heart Association, said Dr. Jonathan Goldin, an assistant professor of radiology at the University of California, Los Angeles. The AHA statement supports the idea of EBCT screening of the heart within the context of a physician-determined risk profile assessment.
The UCLA program uses EBCT scanning for coronary artery calcium screening of at-risk individuals and, on a more limited scale, lung cancer screening of at-risk patients, Goldin said. The program tries to follow a model based on mammography screening: Although patients can walk in, a physician has to be involved to receive and assess the test information.
The future of EBCT screening would be brighter if more efforts were taken to regulate the procedure in a manner similar to that of the Mammography Quality Standards Act, Goldin said. For instance, mammography patients are informed of the percentage chance of a false-negative result.
I think (expanded EBCT) screening will come, he said. It needs to be done in a controlled, regulated fashion. I absolutely believe that a mammography-type model is a good one from that perspective.