AJR: Volume reading speeds mass casualty workflow

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Sixty-four slice CT, coupled with volume image reading, demonstrated significant time savings in a simulated mass casualty incident, according to a study published in the September issue of American Journal of Roentgenology.

The volume reading model accelerated diagnoses following the simulation. “We can make most major diagnoses by the time the patient’s scan is completed,” Markus Korner, MD, department of clinical radiology at Munich University Hospital in Germany, said in a statement.

Mass casualty incidents (MCIs) result in imbalanced resources. The number of patients is high, while medical capacity for diagnosis is limited, according to Korner.

Initial MCI triage typically occurs at the scene of the accident. However, secondary triage at the trauma center assists in resource planning and CT has emerged as a suitable modality for secondary triage. Korner and colleagues hypothesized that 64-slice scanning and volume reading could provide radiologists with images faster than a four-slice system that sends images to PACS.

The study utilized historical data from two previous MCI exercises conducted with a four-slice system. The current simulation entailed secondary CT triage using a 64-slice system and volume reading following a gas explosion and roof collapse.

The simulation assumed that victims had an IV placed prior to arrival and used a phantom for scanning. Staff included a senior and junior radiology resident, two techs and an on-call attending radiologist who arrived at the hospital prior to the first patient.

The CT protocol transferred images during acquisition to a 3D workstation, which processed the isotropic volume dataset using multiplanar reconstructions (MPRs), maximum intensity projections (MIPs) or volume rendering while the CT exam was running.

Patient preparation was slightly longer in the 64-slice simulation than in the control group at 2.1 minutes versus 1.9 minutes, respectively. Mean CT exam time dropped from 2.8 minutes with the four-slice system to 2.7 minutes with the 64-slice system.

The relatively constant timeframes for these metrics indicate the need to employ other methods such as improved data processing and image reading to speed workflow.

With the 64-slice, volume reading model, images were ready for reading after 4.1 minutes, down from 9 minutes with PACS-based image transfer.

Total patient time in the CT room with the 64-slice system was 5.5 minutes, allowing 10.9 exams in one hour.

“This acceleration of the diagnostic process might have a good effect on a patient’s outcome because definitive treatment might be initiated earlier,” wrote Korner.

The researchers referred to a few flaws and advantages of the model. Because volume reading produces temporary reformats, techs need to complete permanent reformats for PACS storage after the MCI.

In addition, the MCI image volume overloaded the CT workstation during the simulation, underscoring the need for a backup system.

Korner and colleagues explained the link between the LAN and image transfer, with a direct connection between the workstation and the CT database mitigating some challenges imposed by a conventional LAN.

Although the study was limited because data were derived from a simulation, it does suggest “the enormous potential” of volume reading to improve workflow, said Korner et al. The researchers called for additional studies to investigate the workflow potential of volume reading.

For further reading about the utility of CT during a disaster, please read "Weathering the storm: CT, EHR prove mission-critical."