Substitution of Magnetic Resonance Imaging for Computed Tomography: An Exploratory Study

Abstract

Despite the importance of understanding factors related to physician adoption and use of diagnostic technologies, relatively few studies have been published. Results of a two-year study of the adoption of magnetic resonance imaging (MRI) and its substitution for computed tomography scanning (CT) are presented. The literature on physician adoption and use of technology is used to provide a framework for this study. Differences in adoption and substitution among medical specialties, early versus late adopters, and high versus low users of MRI are examined. Results show that neurologists and internists more rapidly adopt MRI and substitute it for CT than do orthopedists and other surgical specialists. Referral of higher numbers of patients is the best predictor of more rapid substitution. Physicians who were late adopters more quickly substituted MRI for CT. The cost and social implications of empirical versus "ideal" substitution rates are discussed along with how various regulatory, technology assessment, and financial strategies influence substitution. The role of individual physicians, radiologists, and specialty societies in determining substitution rates is also discussed.

Effect of Computerized Order Entry with Integrated Decision Support on the Growth of Outpatient Procedure Volumes: Seven-year Time Series Analysis

“…Because there was no control group, we could not specifically account for unmeasured external factors operating regionally and nationally that might have served as confounders. These include increasing use of benefits management and precertification for outpatient imaging and changes in reimbursement rates, as well as the above-mentioned concerns about radiation at CT (12)(13)(14)17,18). We can address the first issue by noting that the order entry system was implemented within specific contractual agreements between our group practice and major regional payers to accept ROE and DS system claims without precertification for CT and MR imaging.…”

Magnetic Resonance Imaging: Diffusion of Technology in an Ambulatory Setting

“…This is particularly true in the early stages of the new technology's adoption and when the preexisting modality is noninvasive (9;21). One study of referrals to an MR scanner found initial rates of additive CT/MR ordering of approximately 50% for head and 40% for spine scans; these rates decreased over the 2-year study period (26). In the first 3 years of the present study (the years in which these data are available), 349b of patients had concomitant CT/MR scans of areas imageable by both technologies (joint studies excluded).…”

“…Another pattern that is apparent from our data is the greater adoption of MR by subspecialists over that of primary care providers. It has been suggested in other studies of technology diffusion that subspecialists may adopt new technologies more readily than generalists (1;2;14), although the literature is not in complete agreement on this point (26). Slower rates of adoption among generalists may stem from a lack of familiarity with the new technology or from a greater reluctance to abandon established procedures.…”