ER workflow gets boost from 16-slice CT

September 20, 2005

Use of 16-slice CT shortens emergency room examination times and provides superior image quality, according to researchers at the University of Bern in Switzerland.

Use of 16-slice CT shortens emergency room examination times and provides superior image quality, according to researchers at the University of Bern in Switzerland.

Time devoted to imaging and diagnosis in an ER setting can heavily affect patients, putting finely tuned scanning protocols and workflow at a premium. Available data show that 16-slice CT provides better scanning time and section collimation than does conventional CT scanning. Yet little is said in the clinical literature about workflow in connection with MSCT, the researchers wrote in the July issue of the American Journal of Roentgenology.

Principal investigator Dr. Jan Gralla and colleagues enrolled 503 consecutive ER patients, who underwent 16-slice CT scanning. The investigators measured time intervals, image quality, and tried an innovative "feet-first" setting to scan multitrauma patients. They found their dedicated 16-slicer reduced examination times, even in complex cases, while maintaining high-level image resolution.

A total of 497 patients completed the study, with 39 undergoing multitrauma scanning. Stages included the patient's positioning and image acquisition intervals that made up the "room" time. A "diagnostic" interval combined the former plus the reconstruction and interpretation intervals. Researchers recorded also the "repositioning" interval for multitrauma patients.

Patient positioning averaged eight minutes, depending on the body region examined. In multitrauma patients, initial positioning and repositioning took a mean of six minutes and eight minutes, respectively. Fifty-six patients also underwent CT angiography, taking a mean room time of 21 minutes. Researchers compared results with existing data from a similar clinical setting using a four-slice CT scanner. In the previous study, room time for single body regions ranged between 11 and 22 minutes.

ER 16-slice CT scanning protocols were standardized by body regions including head, cervical spine, thorax abdomen, pelvis, extremities, and thorax (for CTA):

  • sequential/helical mode

  • 0.5 to 1.5-sec rotation time

  • 0.75 to 1.5-mm collimation

  • five to 30-second approximate scanning time (depending on region size)

  • 1, 1.3, or 2 pitch

  • 6 to 30-mm table speed rotation

Most ER centers scan multitrauma patients in a head-first position, which allows fast scanning but at the expense of imaging artifacts from arm positioning and clinical hardware attached to the body. The Bern team introduced a feet-first position for multitrauma patients, turning to head-first only for head and cervical spine cases. Though time-consuming, the procedure showed potential to reduce artifacts to a bare minimum and improve image quality, the researchers said.

The investigators faced several shortcomings. CTA studies proved particularly lengthy. Some patients became too restless and uncooperative for scanning because of the nature of their injuries. Though rare, malfunctioning equipment forced examination delays.

Results might reflect a learning curve, since the evaluation of time intervals in ER scanning started shortly after the installation of the 16-slice scanner. Future studies should elucidate comparisons in similar settings with different types of MSCT scanners, the researchers said.

Further advances should focus on transportation and positioning equipment, because the new generation of 16-slice CT scanners can provide sufficient quality and speed for emergency use, they said.

For more information from the Diagnostic Imaging archives:

Speedy CT makes the most of the 'golden hour' in trauma care

Emergency CT raises issues of timeliness and turf

Rapid multidetector imaging assesses multiple injuries in stable patients