Imaging Weighs the Evidence

Twitter icon
Facebook icon
LinkedIn icon
e-mail icon
Google icon

Studies Build the Case for CCTA, FFDM & PET/CT


Health imaging is one area of healthcare that has seen an unprecedented surge in utilization in the past decade. It is perhaps the fastest rising medical expenditure in the United States with an annual growth rate of 9 percent, nearly one-third more than the annual increase in general medical expenditures (approximately 6 percent). As such, policy-makers and payors are increasingly demanding evidence-based data to justify the utilization of many types of imaging procedures.

Evidence-based medicine—the practice of healthcare interventions guided by or based on supporting scientific evidence—is a topic of great interest among both payors and clinicians. The combined pressures of rising medical costs, longer life expectancy, and a demographic spike in patients 50 years and older has led to the charge that healthcare policy-planners have embraced evidence-based medicine solely as a method to rein in increasing expenditures. Public health officials counter that evidence-based medicine ensures that patients receive the best resources for their care, without unnecessary and wasteful procedures.

According to Bruce E. Hillner, MD, professor and eminent university scholar in the department of internal medicine at Virginia Commonwealth University in Richmond, Va., evidence-based medicine research in imaging has been hamstrung by its failure to perform prospective data collection and sufficiently randomize patients. He said this may be due to a lack of tradition in the imaging community to follow the paradigm of the therapeutic community that does clinical trials.

A major reason for this may be imaging’s role as the middleman in the clinical continuum of care. Imaging clinicians usually are not a patient’s primary-care provider, and typically they do not deliver therapeutic care to a patient as a result of their findings. As such, they generally do not have access to a complete patient history prior to performing an imaging exam and are rarely apprised of a patient’s outcome after delivering their imaging interpretation.

“The kinds of studies that radiologists and nuclear medicine physicians have been used to doing look at the sensitivity and specificity of diagnostic tests and are very uncommonly linked to outcomes; but it’s hard to look at outcomes when you’re only one tiny piece in the chain,” says Barry A. Siegel, MD, professor of radiology and chief of the division of nuclear medicine at the Mallinckrodt Institute of Radiology at Washington University in St. Louis.

“Randomized, controlled trials are very hard to do in diagnostic imaging,” he adds. “Clinicians are reluctant to have patients participate in those trials and patients are reluctant to participate.”

CCTA controversy

Cardiac CT angiography (CCTA) is an imaging procedure that has recently drawn fire from policy-makers eager to rein in imaging expenditures. Despite more than 14,000 published studies on CCTA available via the U.S. National Library of Medicine’s PubMed web site, the procedure’s critics are demanding more evidence-based research.

Although numerous single-site studies have demonstrated the efficacy of CCTA compared with conventional invasive angiography in terms of both cost and outcome in thousands of patients, to date there has not been a comprehensive, nationwide study of the procedure. In the face of overwhelming scientific data supporting utilization for many indications, CCTA detractors point to this omission as justification for their opposition.

However, financing for large-scale clinical trials that can deliver evidence-based data for imaging exams, such as CCTA, is scarce to non-existent.

R. Edward Coleman, MD, professor of radiology and chief of the division of nuclear medicine at Duke University School of Medicine in Durham, N.C., observes that the same governmental and private-payor organizations that are demanding evidence-based imaging data are often reluctant to bankroll the necessary studies. “The challenges are getting the funding to get the studies performed, actually getting the studies performed, getting government approval, and then getting reimbursement from the third-party payors,” he says.

When funding is forthcoming, evidence-based imaging trials can present compelling data for utilization, and reimbursement for, modalities and procedures. Two imaging technologies—full-field digital mammography (FFDM) and PET—cleared the funding gauntlet for evidence-based studies and demonstrated