Dual-Energy CT in the ED Brings Greater Confidence

Using dual-energy CT (DECT) in the emergency department can not only add information and value to the radiologist’s interpretation, but it can also boost how confident the provider is with an analysis. All of that can equate to fewer unnecessary exams and substantial cost-savings.

In a study published this week in the American Journal of Roentgenology, investigators from Vancouver General Hospital shared their experiences with incorporating DECT into their routine emergency department imaging. They found the modality can make an impact on several aspects of radiology even those its use is not yet widespread.

“DECT shows promise in numerous applications, but it is used routinely in only a small number of institutions, mainly academic centers,” said investigator led by William D. Wong, M.D., from the department of radiology at Vancouver General. “DECT added value to routine [emergency department] imaging by increasing diagnostic confidence and leading to a reduction in the number of recommended follow-up studies and a projected cost benefit.”

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To determine the actual impact DECT can have, Wong and his colleagues examined all DECT studies performed in their institution’s emergency department from Jan. 1, 2016, to Dec. 31, 2016 – 3,159 cases total. The studies, which were reviewed by a board-certified radiologist for mentions of DECT, fell into five categories – head and neck, chest, abdomen and pelvis, spine, and musculoskeletal. Scans that did mention DECT were read a second time in a randomized double-blind manner with the mixed image datasets which simulate conventional CT images.

A, Sagittal reformatted bone window CT image of thoracic spine shows wedge-shaped deformity at T6 and subtle superior endplate deformities at T5 and T8. Arrows denote deformities. B, Color-coded dual-energy CT shows only T8 deformity is associated with bone marrow edema; T5 and T6 deformities likely represent chronic fractures. Arrows denote deformities. Courtesy: American Journal of Roentgenology

Based on the team’s analysis, they found DECT findings potentially changed management in 298 (9.4 percent) of cases, increased diagnostic confidence in 455 (14.4 percent) cases, provided additional relevant information in 174 (5.6 percent) of cases, and helped characterize incidental findings in 44 (1.4 percent) of cases. It was dismissed as non-contributory in only three (0.09 percent) of cases, but it was not mentioned at all in 2,272 (71.9 percent) of cases.

The team also found that DECT helped patients avoid unneeded follow-up studies. When it was used, patients were able to avoid 162-to-191 MRI examinations, 21-to-28 CT examinations, and 2-to-25 ultrasound examinations compared to the impact of using CT alone. If did, however, prompt providers to conduct one additional interventional angiography procedure, one ventilation-perfusion scan, and one image-guided biopsy. 

By enabling patients and providers to forego these unneeded exams, DECT also led to significant cost savings. Using the U.S. Centers for Medicare & Medicaid Services Physician Fee Schedule and the 2019 Current Procedural Terminology codes, the team determined DECT produced a net overall savings of $52,991.53 among the lowest-cost studies, as well as a net savings of $61,598.44 among the most costly exams.

According to their analysis, the team said, DECT had the greatest impact on musculoskeletal scans, altering treatment in 266 of 298 cases -- and most of those cases were intended to confirm gout (185 of 266 cases).

“The large number of mentions of the use of DECT to evaluate gout is appropriate. Acute gout is a common [emergency department] presentation and is also ruled out with DECT in other presentations, such as suspected septic arthritis, osteomyelitis, back pain, and acute joint pain,” the team said. “The gout application is particularly useful in areas not amenable to joint aspiration, such as periarticular tissues, tendons, and ligaments.”

Overall, the team said, their findings highlight the value of DECT brings to radiologists.

“Our study…establishes that DECT can provide additional information that reduces recommendations for follow-up imaging with a projected cost benefit in routine clinical practice,” they said. “Moreover, the increase in reader confidence attributed to DECT implies faster turnaround time to diagnosis. This would result in further cost reduction due to shorter hospital stays and improved patient care.”

Still, further research is needed to evaluate the factors that influence how referring providers adapt to DECT, as well as how much trust they put in the added value the scans bring to the table, the team said. Vancouver General is working to reach that goal by implementing DECT acquisition for all CT exams performed in their emergency department.