In a way, it all started with Oprah Winfrey. If Dr. Harvey Eisenberg, medical director of HealthView Center for Preventive Medicine in Newport Beach, CA, had not appeared on “The Oprah Show” in November 1999 to promote total-body CT screening, the normal process of introducing a new imaging application might not have been turned on its end.

Two years have passed, and radiology is still topsy-turvy in the wake of the sensation that Eisenberg’s television appearance precipitated. A new imaging industry has been created, consisting of well-financed companies such as HealthView, CT Screening International (CTSi), AmeriScan, and HealthScreen America. Hundreds of screening services have been established across the U.S. Thousands of total-body procedures have been performed, and the media have publicized claims that those services have saved lives by uncovering hidden diseases.

The controversy surrounding total-body CT screening has caused a schism in the radiological community. Along with Eisenberg, other radiologists such as Dr. Michael Brant-Zawadzki and Dr. Craig Bittner have become vocal advocates of total-body screening. Alarmed by the lack of scientific studies to validate the technique, Dr. Robert Stanley, president of the American Roentgen Ray Society, and other prominent radiologists have voiced opposition. In September 2000, the American College of Radiology issued a warning that expressed misgiving about total-body CT screening. It concluded that there is no evidence to support the claims that CT screening saves lives or money.

But according to Eisenberg, total-body scanning is the future of medicine. Its acceptance is inevitable, and radiologists should ensure that they are at the center of its use in community practice, he said.

Stanley worries that premature adoption of total-body screening will ruin long-standing efforts to raise the scientific rigor of imaging research. From Stanley’s perspective, radiological science would take a step backward if it supported the adoption of a costly imaging technique before it is clinically validated.

“Total-body CT is like taking a very sophisticated jet plane for a joy ride. That is not what it was designed for,” he said. “The people who are making a financial killing with this are misleading the public, and unfortunately, the public is easily misled.”

Yet the issues associated with CT screening are not easily categorized. Total-body CT is a complex test comprising three major components: coronary artery calcium scanning, low-dose lung scanning, and virtual colonoscopy. Each has its own history, advocates, and detractors.

Partial Acceptance

Many critics of total-body CT have come to believe in the diagnostic power of some of its components and are adopting them for use. Dr. Bruce Hillman, chair of radiology at the University of Virginia, has complained about wasted spending on false positives from CT screening, but he is installing CT lung screening, calcium scoring, and virtual colonoscopy in his department this year. Stanley has also purchased software to perform the three tests in his department at the University of Alabama, Birmingham. Massachusetts General Hospital does not market its total-body and other CT screening services, but they are posted on its Web page and are performed at the patient’s request.

CT screening owes a debt to screening mammography in terms of its objectives, the relationship between radiologist and patient, and the public’s acceptance of it as an imaging technology that diagnoses cancer early enough to effect a cure.

The examinations use several imaging technologies that reached maturity in the late 1990s. Coronary artery calcium screening was perfected using electron-beam CT, developed by Imatron, a South San Francisco company that was acquired in September by GE Medical Systems. EBCT replaces the x-ray tube of conventional CT with an electron gun that cuts scan times to as little as 50 msec. It has proved to be a relatively inexpensive way to measure coronary artery calcification, a good predictor of an individual’s susceptibility to future cardiac events.

Because EBCT captures hundreds of slices in seconds, Eisenberg chose it for total-body CT screening. A volumetric acquisition from the neck to the pelvis taking about 20 seconds enables him to perform a calcium test, lung cancer screening, a bone density test, and an abdominal survey to detect emphysema, benign tumors, thoracic cancers, aneurysms, kidney and gall stones, endocrine system diseases, and prostate cancer. Optional virtual colonoscopy was recently added.

Dr. Claudia I. Henschke, chief of chest imaging at Cornell University-Weill Medical College, and Dr. David P. Naidich, director of thoracic imaging at New York University, developed their 20-second low-dose CT lung cancer screening protocol in 1993 on a spiral CT scanner. That technology continues to be used in the Early Lung Cancer Action Project (ELCAP), the main clinical trial that is testing the diagnostic power of this exam.

The National Cancer Institute is sponsoring trials at the Mayo Clinic in Rochester, MN, and elsewhere to determine how well multislice CT performs the protocol. New eight- and 16-slice multidetector cameras will probably become the first choice of radiologists who perform total-body CT or any of its component exams. Cardiologists have accepted EBCT for coronary calcium testing.

Early Detection

Detecting disease early is the key benefit of CT screening, according to Bittner, medical director of AmeriScan. Heart disease and lung cancer will cause more than half of all deaths in the U.S. this year. Colorectal cancer, the target of virtual colonoscopy, is second only to lung cancer as the biggest cancer killer.

Screening is based on the premise that most fatal diseases progress over many years before they kill their host, Eisenberg said. Arteriosclerosis, for example, develops over 30 to 40 years. Its expression is often an explosive process that causes death in one-third of all first heart attacks. Cancers tend to have a long period of preclinical development during which early detection and intervention can often produce a cure.

Unlike diagnostic radiology, CT screening caters to the asymptomatic patient, according to Brant-Zawadzki, medical director of CTSi’s Newport Imaging Center. Within the screening context, the radiologist acts as the physician who communicates the results directly to the patient. Rather than accepting referrals as in conventional radiology, the radiologists refers patients to subspecialists for follow-up.

“This concept has taken the radiologist from the back room of consultative practice to the front room where primary care is performed,” he said.

The upscale versions of these services use three-dimensional reconstructions of the imaging results and long consultations with patients to persuade them to modify behaviors that make them susceptible to cancer and cardiovascular disease.

“This approach gives them an opportunity to take responsibility for their health. It is all about motivation and education,” Bittner said.

Many aging baby boomers can afford to pay $800 to $2000 for a total-body test. They are angry enough with their managed-care providers to use this type of examination as a way around the obstacles to first-class care. A total-body scan can provide diagnostic evidence that forces managed-care providers to grant access to therapy when abnormalities are found.

Major medical problems are sometime avoided because of a total-body scan. A case in point is the experience of a patient whose total-body scan, performed at AmeriScan in Scottsdale, AZ, revealed severe carotid artery blockage that led his managed-care doctor to prescribe ultrasound, MR angiography, and contrast angiography. Three months later, these procedures confirmed 99% blockage in the left carotid artery and 55% blockage in the right carotid artery, Bittner said. Carotid endarterectomy was performed the next morning.

Excluding coronary calcium tests, nearly 32% of the 1807 patients examined CTSi’s Newport Beach clinic between January and September of this year had abnormal findings, Brant-Zawadzki said. Among these cases, 248 clients had noncalcified pulmonary nodules. The staff identified 17 cancers, including lung, liver, vocal chord, pancreatic, and kidney cancers and lymphoma. They also found a 4% incidence of kidney stones and a 3% incidence of gallstones. Chronic obstructive pulmonary disease was found in 44 patients. Thirty ovarian cysts, 20 thyroid lesions, 17 renal lesions, 10 adrenal lesions, eight ovarian/pelvic masses, five cases of hydronephrosis, 11 aneurysms, and two cases of congestive heart failure were identified.

According to Eisenberg, 97% of all total-body studies performed at his Newport Beach uncover clinically significant pathology.

Missing Evidence

A problem with total-body CT is that no statistically valid evidence exists to show that it does any good. In lieu of trials investigating the total-body tests, proponents rely on anecdotes and results of trials that were designed to examine its coronary calcium, lung cancer screening, and virtual colonoscopy components.

Dr. Stephen Swensen, director of radiology at the Mayo Clinic, said he is not ready to judge the value of total-body CT despite performing 5000 whole-body procedures since 1997.

“The awkward thing is where you see people advertising these services directly to patients and implying that the science has already been performed and they have been endorsed by society and leaders in the medical community. In reality, that has not happened yet,” Swensen said.

Brant-Zawadzki counters that the results of trials for coronary artery calcium scoring, lung cancer screening, and virtual colonoscopy apply because those tests are imbedded in a total-body scan. The radiologist has a responsibility to evaluate the extra anatomic data that are collected when the body is scanned from the head to the hips, he said.

“The rest of it is really icing on the cake. You can’t throw away that information. You can’t throw away evidence of a kidney cancer because there is no evidence that the study is valid. That is unrealistic,” he said.

Swensen is also concerned about false positives, a problem that appeared in his own study of CT lung cancer screening. Key differences between his work and Henschke’s include his use of a multislice scanner, 5-mm slices (Henschke used 10-mm slices), soft-copy interpretation, and the prevalence of histoplasmosis in the upper Midwest.

Swensen’s study of 1520 high-risk subjects uncovered 2722 noncalcified lung nodules. Thirty-three were cancerous, but 99% of the nodules were determined by observation to be benign. In the second year, 13% of the Mayo subjects had a new nodule, and a very high percentage of those were also benign, he said.

“These preliminary results tell me that this exam should not be promoted to the general public. It is not justified scientifically,” he said.

But according to Brant-Zawadzki, the Mayo lung study also uncovered 210 incidental findings in 14% of the subjects. They included carcinoid, renal, and breast cancers, lymphoma, and 51 abdominal aortic aneurysms, he said.

Market Potential

The criticism has not cooled interest in opening new centers to meet public demand. The U.S. can probably support about 4000 total-body imaging services, said Dr. Richard Penfil, a radiologist who is CEO of CTSi. Between 15 million and 20 million Americans are potential candidates for the scans.

Total-body services are cropping up across the country. Virtual Physical operates in Pikesville, MD. Total Body Scan Centers of South Florida opened its first center in Aventura, FL, in July. Millennium Scan opened in Washington, DC, in June and was performing 18 procedures a day by September.

Eisenberg has arrangements with university partners to build 14 new HealthView centers. His Newport Beach facility screens 74 patients a day, seven days a week, and is booked up for the next year. AmeriScan and CTSi will each have seven sites operating by year’s end.

Radiologists should consider starting their own services only if it fits their mission statement and strategic plan, said Dr. Lawrence Muroff, CEO of Educational Symposia. If there is a fit, moving swiftly is important. The clinics that get in on the ground floor have the greatest prospects for success, he said.

“This is going to be a very competitive business,” Muroff said. “The prices we are seeing now are not sustainable, and whether public interest will be sustained has yet to be determined.”

Marketing a high-volume screening operation is not for the faint of heart, said Phil Voluck, chief of marketing for CTSi. Without a conventional referral base, the need for promotion is unrelenting. To thrive in a major metropolitan market such as Los Angeles, a screening center can expect to spend $200,000 a month on TV, radio, and newspaper advertising. The monthly cost in a smaller market such as Detroit would be about $30,000.

Around The Country

Radiologists in Tucson, AZ, expect that screening will be introduced in the area, but local entrepreneurs may squeeze them out of the business, said Dr. Kenneth Burroughs, a neuroradiologist at Northwest Hospital. Local businesspeople have reportedly hired consultants to advise them on starting screening services. And radiological professional fees at some centers around the country have purportedly fallen to $40 for a complete total-body study.

“If you get a radiologist to work for a low bid, you are going to get a low-bid interpretation,” Burroughs said.

CT screening is one of several ingredients of the comprehensive physical examination featured by HealthScreen International in Jacksonville, FL. The emphasis here is the ultimate physical exam as envisioned by internists, such as Dr. Eduardo J. Balbona, chief medical officer. He teamed with former managed-care magnates Christopher Fey and Frederick Fey to organize HealthScreen in early 2000. Its first facility in Jacksonville has been operating for a year, and a second service in Atlanta is under construction. The menu of services, which cost from $180 to $2000, combines metabolic analysis with imaging. A client may receive a coronary calcium test, for example, but cholesterol, homocysteine, C-reactive protein, lipid profile, and carotid intermedial thickness are checked as well. A radiologist reads the CT studies.

Patient communications are handled according to exam results. If everything is normal, the results are communicated in a 30-page brochure. A nurse handles the consultation if there is a mild abnormality; an internist intervenes if it is serious. In many cases, there is a physician-to-physician hand-off in which results are communicated to the personal physician who performs the consultation.

“HealthScreen is a physician extender. We are not here to replace doctors; we are here to augment them,” Balbona said.

CATscan 2000

While HealthScreen caters to the well-to-do, CATscan 2000 is geared toward the middle class. Founded by entrepreneur Gina Johnson in 1999, CATscan owns six mobile CT systems that circulate in Florida, Georgia, Tennessee, Illinois, Ohio, Indiana, and Arizona. The trailers are equipped with Marconi PQ 2000S scanners. The single-slice machines were the only CT systems considered durable enough to withstand the rigors of the road when they were purchased two years ago, said Dr. William S. Maxfield, a radiation oncologist.

The company charges $195 for coronary calcium, lung screening, or abdominal scan. The price for all three is $567. A certified radiologic technologist copies the studies on a DICOM-compatible disk that is shipped to the company in Clearwater, FL, where studies are read by one of five part-time board-certified radiologists.

Clients receive normal results in the mail about 10 days after the procedure. A brochure helps them understand what the results mean. Abnormal findings are rushed via Federal Express to the patient and the designated personal physician. The company’s radiologist makes recommendations for follow-up, Maxfield said.

Compromises were made to maintain low prices. Age criteria are liberal. For its coronary calcium test, the firm will test males who are 40 and over and have no history of heart disease and women 45 and over with no history of heart disease or possibility of pregnancy. It will accept clients as young as 40 for lung and abdominal scans. ECG gating techniques that would reduce motion and misregistration artifacts are not used because of limitations encountered in a mobile environment, Maxfield said.

Collaboration In Denver

Radiology Imaging Associates, a 45-member radiology group in Denver, is relying on collaborations with its traditional referral sources to generate patient volume and consultative follow-up as it adopts components of the total-body exam.

The group is not interested in directing their services to the worried well, according to Dr. Richard Obregon. They prefer to identify at-risk populations who will gain the greatest clinical benefit from these services.

A CT lung cancer screening program will be restricted to men and women over 50 who have smoked the equivalent of one pack of cigarettes a day for one year. The program will be launched at the group’s multimodality Invision Diagnostic Imaging Center in the second quarter of 2002. Pulmonologists and primary-care physicians will be the main referral sources and will follow up to definitively diagnose and treat symptomatic patients. The group is developing patient education materials and is considering whether to copy the images on a CD-ROM so the patient can view them at home.

“The pulmonologists have to be on board for all this to work. They have to be knowledgeable about what we are doing and understand when our criteria call for bronchoscopy or biopsy to evaluate suspicious nodules,” Obregon said.

Over time, the group plans to introduce virtual colonoscopy and perhaps coronary calcium testing, if cardiologists in the area request it. The group also intends to eventually incorporate whole-body PET to screen at-risk patients for malignancies.

Other iterations of CT screening are appearing elsewhere. Apart from the high-volume glitter of the total-body services, community-based radiologists are cautious about adopting services too soon and skeptical of procedures that promise a panacea. Their attitude is perhaps the clearest indication of how radiologists regard the CT screening phenomenon.

Sidebar

Pros and Cons of CT screening

Coronary Artery Calcium Test

Pro: A negative test is highly unlikely in the presence of significant luminal obstructive disease. A positive test confirms the presence of coronary atherosclerotic plaque. The greater the amount of calcium, the greater the likelihood of occlusive disease, but there is not a one-to-one relationship. The amount of calcium correlates best with the total amount of atherosclerotic plaque, although the extent of disease may be underestimated. All but one major study established sensitivity rates above 90%, and the exception was 85%. Specificity, however, varied from 44% to 76%. A study published in 2000 indicates that multislice CT works as well as electron-beam CT for this test.¹ ECG-gated spiral CT is adequate.²

Con: The American Heart Association does not recommend the routine use of the test in patients without heart-related symptoms unless standard cardiac risk assessment techniques have proved insufficient. Cardiologists believe EBCT has a role for some patients, but they don’t plan to adopt the technique as a screening tool soon.

Low-Dose CT Lung Cancer Screening

Pro: Second-year results of the Early Lung Cancer Action Project (ELCAP) trial provide evidence favoring serial screening of older long-time smokers. The baseline study found suspicious nodules in 23% of patients; 12% were malignant, and 82% of those were stage IA cancers. Second-year follow-up identified new nodules in 1.5% of subjects, and 43% of those nodules were malignant. Researchers have learned to evaluate solid, part-solid, and nonsolid nodules. In the second-year trial, 7% of solid nodules, 63% of part-solid nodules, and 18% of nonsolid nodules were malignant.³

Con: The false-positive rate rises when thinner slices are used. Limited evidence supports the premise that earlier detection with this test actually saves lives. The National Cancer Institute will spend $2 million in fiscal 2002 to assess the feasibility of a definitive clinical trial and has requested $20 million in its 2003 budget for the study itself. Discipline is required to limit screening to high-risk clients over 60 with at least 10 pack-years of smoking history.

Virtual Colonography

Pro: Endoscopic colonoscopy or double-contrast barium enema is already recommended as a periodic screening test to detect colorectal cancer in people over 50. Virtual colonography is seen as way to overcome public reluctance to undergo the procedure. The five-minute exam requires no sedation and covers the entire colon. In clinical trials, it comes close to matching the performance of conventional colonoscopy.⁴ Software advancements overcome interpretation and anatomic coverage problems.

Con: Multisite prospective trials are still needed to confirm the diagnostic power of virtual colonoscopy in asymptomatic patients. The NCI has budgeted funds in fiscal 2003 for clinical trials to compare it with endoscopic colonoscopy. Polyps hidden in the folds of the colon can be missed and normal anatomy can mimic disease. Like mammography interpretation, it takes time to learn.

References

1. Becker CR, Kleffel T, Crispin A. Coronary artery measurement: agreement of multirow detector and electron beam CT. AJR 2000;176:1295.
2. Carr JJ, Crouse, JR, Goff, DC, et al. Evaluation of subsecond gated helical CT for quantification of coronary artery calcium and comparison with electron beam CT. AJR 2000;174:915-921.
3. Henschke CI, Naidich DP, Yankelevitz DF, et al. Early Lung Cancer Action Project: initial findings on repeat screenings. Cancer 2001;92(1):153-159.
4. Yee J, Geetanjali AA, Hung RK, et al. Colorectal neoplasia: performance characteristics of CT colonography for detection in 300 patients. Radiology 2001;200:157-160.