Several publications from the 2000s suggested that as many as 20%–50% of high-tech imaging procedures, such as CT scans, fail to provide information that improve patient welfare and therefore may represent, at least in part, unnecessary imaging services. An informal estimate, made at a 2001 conference, was that perhaps 10 – 30% of pediatric CT examinations were not necessary.
As a result, attention has turned to appropriate use of diagnostic imaging studies. A diagnostic imaging study can be considered appropriate when the expected health benefit (i.e., increased life expectancy, pain relief, reduction in anxiety, improved functional capacity) exceeds the expected negative consequences (i.e., mortality, morbidity, anxiety of anticipating the procedure, pain produced by the procedure, time lost from work) by a sufficiently wide margin that the procedure is worth doing.
Evaluation of appropriateness can be difficult, because in many cases, published appropriateness criteria are not applicable to all types of patients seen in routine practice. In many cases insufficient evidence exists for experts to achieve consensus on the appropriateness of a particular indication. (1) The 2014 RAND Corporation report on the Medicare Imaging Demonstration (MID) project suggested that between 4% and 26% of imaging studies that could be evaluated were inappropriate, depending on the specific imaging study and the institution at which appropriateness was evaluated.(1) The Rand report also reviewed a number of published reports of decision support system (DSS) use. A DSS synthesizes existing evidence on the effectiveness of each procedure, including appropriateness criteria developed by physician specialty societies. Physicians use DSS to help base decisions on the current evidence at the point of care. A DSS provides immediate feedback to the physician on the appropriateness of a test or treatment ordered for a patient. After the introduction of a DSS to aid physicians in selecting an appropriate examination, the rate of inappropriate examinations decreased in most published reports. DSS can improve the likelihood of appropriateness even when the vast majority of studies are already appropriate. For example, at Massachusetts General Hospital, the percentage of “low utility” studies decreased from 6% to 2% after the introduction of a DSS.
The FDA strongly promotes the efforts of other organizations in the area of appropriate justification of imaging exams through the development and adoption of appropriate-use criteria. An important aspect of reducing unnecessary exams is access to a patient's imaging history (see Education and Communication section). In addition, development and implementation of evidence-based appropriate use guidelines is crucial. Examples of efforts to promote appropriate use of imaging include:
- The American College of Radiology publishes online, publicly accessible appropriateness criteria® to assist referring physicians and other medical professionals in making imaging decisions based on specific clinical conditions.
- The American College of Cardiology developed appropriate-use criteria for a variety of diagnostic imaging modalities and procedures used by cardiovascular professionals.
- FDA presented at the National Council on Radiation Protection and Measurements (NCRP) workshop (September 2009) on "CT in Emergency Medicine: Ensuring Appropriate Use." Summary recommendations were recently published.
- The FDA presented at the International Atomic Energy Agency (IAEA) technical meeting on Justification of Medical Exposure in Diagnostic Imaging.
- The American Board of Radiology Foundation held a 2009 summit on "Medical Imaging: Addressing Overutilization in the Era of Healthcare Reform".
- An update to the American Dental Association /FDA "The Selection of Patients for Dental Radiographic Examinations" was published in November 2012. The focus of this document is on appropriate use guidelines. FDA provided comments on the ADA’s advisory statement on "The use of cone-beam computed tomography in dentistry" (published August 2012), which focuses on appropriate use of this technology.
- Federal Guidance Report No. 14 (Radiation Protection Guidance for Diagnostic and Interventional X-Ray Procedures) recommends the use of DSS in federal medical facilities.
- FDA is contributing to the development of a new International Commission on Radiological Protection (ICRP) draft publication on justification in medical imaging.
1. Timbie JW, Hussey PS, Burgette L, et al. Medicare Imaging Demonstration Evaluation Report for the Report to Congress. Final Research report. Report RR-706-CMMS. The Rand Corporation, Santa Monica, CA; 2014.