While pressure to justify the appropriateness of imaging remains ubiquitous, newly published research may offer some defense for use of CT of the abdomen and pelvis (CTAP) in the ED as it appears to be preferentially used in patients classified as clinically complex, according to a study appearing in the June issue of the Journal of the American College of Radiology.

Specifically, CTAP is nearly six times more likely to be utilized in higher complexity ED patient encounters compared with less clinically complex cases, according to Richard Duszak, Jr., MD, of the University of Tennessee Health Science Center in Memphis, and colleagues.

”Understanding the complexity of patient encounters in which advanced medical imaging services are frequently delivered might be useful in aiding payers and policymakers in explaining the growth of advanced imaging services over the past decade and determining the context in which these examinations are appropriately being used,” Duszak said in a release.

Use of advanced imaging in the ED, CTAP in particular, has increased in recent years based on evidence that it shortens wait times, decreases the frequency of unnecessary exploratory surgery and facilitates triage of both trauma and nontrauma patients, according to the authors. Despite these demonstrated benefits, some stakeholders have questioned the appropriateness of increased utilization of CTAP, arguing that rather than using it for these benefits or among sicker patient populations, physicians are ordering the exams to appease patients with less complex conditions.

“In addition, some policymakers have asserted that mispricing of services, rather than proven clinical utility for increasingly complex patients, has led to rapid increases in the utilization of these and other advanced imaging services,” wrote the authors. “This belief has led to the promotion of policies attempting to curb utilization by decreasing payments for CTAP and other imaging services.”

To better assess utilization patterns of CTAP, Duszak and colleagues identified ED visits for Medicare fee-for-service beneficiaries using the CMS 5 percent Medicare files for 2007. Contemporaneous ED physician evaluation and management (E&M) codes were used as the basis for patient complexity categorization. Encounters in which CTAP was performed on the same date of service were identified, and variables affecting the utilization of CTAP were analyzed.

Of the 1,081,000 ED encounters included in the study, 774,599 were of higher complexity. CTAP was performed in 6 percent of all encounters.

The overwhelming majority of patients undergoing CTAP in the ED were classified as clinically complex. Of the 65,273 encounters associated with CTAP, 93.8 percent were of higher complexity. “Although 28.3 percent of ED patient encounters were categorized as low complexity on the basis of our E&M coding criteria, only 6.2 percent of ED CTAP was performed in this patient group,” summed the authors.

Duszak and colleagues also commented on the relationship between patient encounter complexity and the imaging of contiguous body parts. “Government agents have recently asserted considerable physician efficiencies when imaging studies on multiple body regions are interpreted on the same date of service. Despite published evidence to the contrary, this belief has been used as the rationale for large Medicare fee cuts for advanced medical imaging for 2012. Dissenting commentary indicated that multiple body part imaging is more often performed in the setting of more complex patient conditions, and our results support that contention.”