In recent years, there has been great demand to prove the value of health imaging though published cost-utility analyses (CUAs), but while these studies generally focus on the impact of interventions in terms of quality-adjusted life-years, they often overlook the intrinsic value of imaging unrelated to treatment, according to an article published in the May issue of Academic Radiology.

In addition to some of the more easily measured benefits, diagnostic imaging has planning value, in that it helps patients make better decisions, and psychological value related to patients’ senses of themselves, according to Hansel J. Otero, MD, and colleagues at Tufts Medical Center in Boston. These benefits to emotional, social, cognitive or behavioral outcomes—the so-called intrinsic value—are not captured in current CUAs. Measurements of variation in imaging test accuracy, inconclusive results and associated risks also have lacked uniformity in the literature, according to the authors.

“The challenge of linking radiology to outcomes beyond the traditional model remains an important topic for radiologists because diagnostic test results are intermediate outcomes that do not directly determine patients’ health outcomes,” wrote Otero et al. “The validation of methods to determine the value of imaging beyond changes in treatment should be made a priority for health economic researchers.”

The researchers systematically reviewed literature on the value of imaging covering CUAs published between 1976 and 2008. Ultimately, 96 published CUAs evaluating 155 different imaging technologies were included in the final sample. Slightly more than half evaluated the performance of a single modality, with the most common areas of interest being cardiovascular imaging and neuroradiology.

Only 23 percent of the CUAs considered inconclusive or indeterminate results, and risk of testing was reported for 21 percent of imaging technologies.

The intrinsic value of imaging unrelated to treatment was addressed in 16 percent of CUAs, and the majority of those instances were merely mentions in the discussion or limitations sections of the study.

“Although attempts have been made to measure and model the prognostic value of imaging, none of the publications incorporated this type of metric into their analyses,” wrote the authors. “We hypothesize that investigators might have tried to avoid the introduction of additional uncertainty and potential bias.”

The authors suggested that future research incorporate a reasonable rate of inconclusive results, as that would more closely resemble real-world clinical practice. Radiation risk, now a more common concern both in radiology and among the general public, should be accounted for as well to enhance the value of the studies and make a more fair comparison between management plans.

“Similarly, the incorporation of imaging test accuracy with its variations, inconclusive results, and imaging test risks has lacked uniformity in the cost-utility literature,” wrote the authors. “Acknowledgment of these characteristics in future cost-utility publications evaluating diagnostic imaging will enhance their value and provide results that more closely resemble routine clinical practice.”