title: Accuracy and Precision of Three-Dimensional Low Dose CT Compared to Standard RSA in Acetabular Cups: An Experimental Study.
abstract: Background and Purpose. The gold standard for detection of implant wear and migration is currently radiostereometry (RSA). The purpose of this study is to compare a three-dimensional computed tomography technique (3D CT) to standard RSA as an alternative technique for measuring migration of acetabular cups in total hip arthroplasty. Materials and Methods. With tantalum beads, we marked one cemented and one uncemented cup and mounted these on a similarly marked pelvic model. A comparison was made between 3D CT and standard RSA for measuring migration. Twelve repeated stereoradiographs and CT scans with double examinations in each position and gradual migration of the implants were made. Precision and accuracy of the 3D CT were calculated. Results. The accuracy of the 3D CT ranged between 0.07 and 0.32 mm for translations and 0.21 and 0.82° for rotation. The precision ranged between 0.01 and 0.09 mm for translations and 0.06 and 0.29° for rotations, respectively. For standard RSA, the precision ranged between 0.04 and 0.09 mm for translations and 0.08 and 0.32° for rotations, respectively. There was no significant difference in precision between 3D CT and standard RSA. The effective radiation dose of the 3D CT method, comparable to RSA, was estimated to be 0.33 mSv. Interpretation. Low dose 3D CT is a comparable method to standard RSA in an experimental setting.
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden.
authors.forename: Cyrus
authors.identifier: 0000-0002-9801-2733
authors.initials: C
authors.lastname: Brodén
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Olivecrona
authors.affiliation: School of Information and Communication Technology, KTH Royal Institute of Technology, 16440 Stockholm, Sweden.
authors.forename: Gerald Q
authors.initials: GQ
authors.lastname: Maguire
authors.affiliation: Department of Radiology, New York University School of Medicine, New York, NY 10016, USA.
authors.forename: Marilyn E
authors.initials: ME
authors.lastname: Noz
authors.affiliation: School of Computing, College of Engineering, University of Utah, Salt Lake City, UT 84109, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Zeleznik
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Olof
authors.identifier: 0000-0003-4155-8425
authors.initials: O
authors.lastname: Sköldenberg
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D007595:Joint Prosthesis; D007596:Joints / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D010384:Pelvic Bones / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D059869:Radiostereometric Analysis / Q000379:methods*; D014055:Tomography, Emission-Computed / Q000379:methods*