Evaluation of Crossover Sign in Pelvis Models Made with a Three-Dimensional Printer

Abstract

Introduction. Investigation of the crossover sign (COS) in different degrees of tilt in pelvises made by three-dimensional printing of CT scans among patients with normal hip versions was carried out. Methods. Radiology CT scans of 8 normal pelvises reconstructed in 3D and the effect of sequential tilting on the presence of the false-positive COS in 48 radiographs were investigated. Results. The COS was seen in 77% of the AP radiographs during tilt changes. The average distance between the tip of the coccyx and the symphysis pubis was 32.06 ± 10.99 mm. Also, COSs were present in all radiographs from 6 degrees tilt and above. Conclusion. Minor tilting of the pelvis can result in a false-positive crossover sign on AP plain radiographs.