Results of a 5 Year, 10,000 Scans Experience with Weight-Bearing CT. Impact on Costs, Radiation Exposure and Time Spent
Authors: Richter Martinus , Lintz Francois , de Cesar Netto Cesar , Barg Alexej , Burssens Arne 
Published: October 2019

Category:

Radiolography

Introduction/Purpose:

Weight-bearing CT (WBCT) has been proven to allow for more precise and valid measurement of bone position than conventional weight-bearing radiographs (R) and conventional CT without weight-bearing (CT). Time spent for image acquisition has been shown to be lower for WBCT than for R and CT. Radiation dose for WBCT has been shown to be lower for WBCT than for CT. A WBCT device (PedCAT, Curvebeam, Warrington, PA, USA) had been brought on line July 1, 2013 in the first author´s foot and ankle department. The purpose of this study was to assess the benefit of using WBCT instead of R and/or CT in a foot and ankle center regarding time spent for image acquisition, radiation dose, disturbances, and cost effectiveness.

Methods:

All patients who obtained WBCT (PedCAT)from July 1, 2013 until September 30, 2018 were included in the study. Age, sex, primary pathology were analyzed. The time spent for image acquisition (T) was calculated based on an analysis of previous study as follows: R (bilateral feet dorsoplantar and lateral, metatarsal head skyline view), 902 seconds; CT (bilateral feet and ankle), 415 seconds; WBCT (bilateral), 207 seconds. Radiation dose (RD) per patient was calculated based on previous phantom measurements as follows: R, 1.4 uSv; CT, 25 uSv; WBCT 4.2 uSv1. For analysis cost effectiveness, device cost, reimbursement and working time cost of radiology technicians were taken into consideration within the local circumstances. All parameters were compared between the time period using WBCT (yearly average) with the parameters from 2012, i.e. before availability of WBCT.

Results:

10,087 WBCT scans were obtained in 4,702 patients (4,702 (47%) before treatment; 5,385 (53%) follow-up; mean age, 52.0; 40% male). Primary pathologies were forefoot deformities (n=916 (20%) and ankle instability/cartilage defect (n=534 (13%)), and hindfoot deformity (n=480 (10%)). 1,940 WBCT scans were obtained on average yearly, and 10.4 CTs (WBCT group). In 2012, 1,850 R and 254 CTs were obtained (R(+CT) group). Yearly RD was 4.4 uSv for WBCT group and 4.8 uSv for R(+CT) group (difference 0.4 uSv decrease with WBCT 8%, p<0.01). Yearly T was 127 hours in total (3.6 minutes per patient) for WBCT group and 959 hours in total (15.6 minutes per patient) for R(+CT) group (difference, 832 hours, decrease with WBCT, 87%, p<0.01). Yearly profit was 47,545/-816 Euro for WBCT/R+(CT).

Conclusion:

10,087 WBCT scans in 4,702 patients as substitution of R(+CT) over a 5.3 year period at a foot and ankle center resulted in 8% decreased RD (minus 0.4 uSV on average per patient). Yearly T decreased 832 hours (87%) in total (12.0 minutes per patient). Yearly financial income increased more than 48,000 Euro in total (24 Euro per patient). RD decreased despite higher radiation dose for WBCT than for R alone, based on substitution of a high number of CTs by WBCT. Other centers with low usage of CT might not decrease RD by substituting R alone by WBCT.