Computer Simulation in the Analysis of Computed Tomography Exam Times

Computed Tomography (CT) is one of the most important tools in diagnostic imaging. In Brazil, among medical imaging devices, 4.7% were CTs, representing eighth place in exam numbers and first in costs. The aim of this study was to evaluate the effect of faster CT equipment on total exam time (from patient arrival to departure). To this end, exams were divided into six steps: patient arrival, patient movement in the examination room, patient positioning, data entry, image acquisition and patient exit. Step duration was measured on 84 exams with 1, 4 and 128-slices CTs in 5 private clinics/hospitals, in 2014/2015. Models were created in the MedModel (R) software and thirty days were simulated for a hospital operating 24 h/day. Scenarios were simulated for three types of CTs using the average times obtained from the exams. In the model, except for the acquisition stage, the times from each step were the same for all CT types. Simulations showed that, for example, a single slice CT running inpatient examinations at night (8:00 PM-7:00 AM) and adding another dressing room could decrease total exam time by approximately 33%; while replacement of a single slice CT by a 4 slices model (more expensive) would result in a much smaller overall time reduction. In conclusion, productivity gains may be smaller than expected when replacing simpler models by more sophisticated ones, and patient care time is not only a function of the speed of data acquisition, and organizational changes can produce decreases in these times.