G. Scott Gazelle, MD, MPH, PhD Pamela M. McMahon, BS Uwe Siebert, MD, MPH, MSc Molly T. Beinfeld, MPH Published online 10.1148/radiol.2352040330 Radiology 2005; 235:361–370 Abbreviations: CEA = cost-effectiveness analysis NCHCT = National Center for Health Care Technology RCT = randomized controlled trial ROC = receiver operating characteristic 1 From the Institute for Technology Assessment and Department of Radi- ology, Massachusetts General Hospi- tal, Harvard Medical School, 101 Mer- rimac St, 10th Floor, Boston, MA 02114-4724 (G.S.G., P.M.M., U.S., M.T.B.); Department of Health Policy and Management, Harvard School of Public Health, Boston, Mass (G.S.G., U.S.); and PhD Program in Health Pol- icy, Harvard University, Boston, Mass (P.M.M.). Received February 19, 2004; revision requested April 27; revision received May 4; accepted May 24. Ad- dress correspondence to G.S.G. (e- mail: scott@mgh-ita.org). © RSNA, 2005 Authors stated no financial relation- ship to disclose. Cost-effectiveness Analysis in the Assessment of Diagnostic Imaging Technologies 1 In many ways, diagnostic technologies differ from therapeutic medical technologies. Perhaps most important, diagnostic technologies do not generally directly affect long-term patient outcomes. Instead, the results of diagnostic tests can influence the care of patients; in that way, diagnostic tests may affect long-term outcomes. Because of this, the benefits associated with the use of a specific diagnostic tech- nology will depend on the performance characteristics (eg, sensitivity and specific- ity) of the test, as well as other factors, such as prevalence of disease and effective- ness of available treatments for the disease in question. The fact that diagnostic tests affect short-term, or “surrogate,” outcomes, rather than long-term patient out- comes makes evaluation of these tests more complicated than the evaluation of therapeutic technologies. This article will trace the history of technology assessment in medicine, address the role of cost-effectiveness and decision analysis in health technology assessment, and describe unique features and approaches to assessing diagnostic technologies. The article will then conclude with a consideration of the limits of medical technology assessment. © RSNA, 2005 The explosive growth in medical technology and procedures (1–3) during the past several decades has provided physicians with an unparalleled ability to diagnose abnormalities and treat patients. In many cases, however, new technologies and procedures have dif- fused widely without careful assessment of their appropriate roles in the care of patients. The uncertainty around the effectiveness of a diagnostic technology can result in contro- versy; examples of this include the use of computed tomography (CT) in lung cancer screening and mammography in women aged 40 – 49 years (4 –12). The increase in avail- able medical technologies may also have contributed to the nearly continuous increase in health care spending since the 1960s (13), the burden of which has fallen increasingly on the public sector. For instance, 45.9% of national health expenditures in the United States in 2002 were from federal or state funds (14). Heightened awareness of these issues has focused attention on constraining the growth of health care costs. Thus, as both our needs and our capabilities continue to grow in the face of constrained resources, we are increas- ingly faced with the dilemma of choosing either the best tests and procedures or the most cost-effective tests and procedures from among worthy alternatives, rather than merely determining which tests are effective and which are not. In particular, we are confronted with the task of identifying population subgroups for which a diagnostic procedure is clinically beneficial and cost-effective, so that clinical algorithms can be used to consider individual patient characteristics. As we progress further into the current “era of assessment and accountability” (15), more people agree that we must improve and expand our technology assessment techniques and efforts (16 –20). Multiple journals are now devoted to technology assessment; however, neither technology assessment nor its specific application to health care is a new activity. Physicians and others who provide or pay for health care have long been engaged in informal technology assessment with attempts to better understand the effects and rela- tive merits of medical interventions. Clinical research, however, has improved consider- ably, and we now have tools to gather data and compare the efficacies of new and existing technologies. For many of these assessments, the randomized controlled trial (RCT) is the tool of choice. RCTs, described as “the crown jewel of traditional technology assessment” (21), have Special Reviews 361 R adiology