Prospective Comparison of Simulated Low Dose Computed Tomography to Conventional Dose Computed Tomography for the Evaluation of Glenoid Anatomy in Shoulder Arthroplasty

The purpose of this study is to compare the use of a conventional dose computed tomography scan (C-CT) to a simulated low dose computed tomography scan (L-CT) for preoperative planning in patients who are anticipated to undergo a total shoulder arthroplasty (TSA) or reverse shoulder arthroplasty (RSA) with the goal to reduce the radiation exposure to future patients undergoing preoperative planning. L-CT scans for analysis will be obtained prospectively as derived data from a C-CT scan performed on a dual source CT scanner. Briefly, a C-CT scan will be conducted, with scan images representing a reconstruction of simultaneous scans at two sensors. L-CT images will be derived from single source data (ie the scan data gathered by one of the emitters rather than a reconstruction from both). For additional validation, prospectively collected scans will be compared to retrospectively gathered scans of patients of similar demographics (age, sex, BMI) and degenerative changes who underwent a C-CT scan for an anticipated shoulder arthroplasty in the past. The reviewers will investigate the following outcome measures including 1) Are L-CT images of sufficient quality to be used for preoperative planning 2) Can accurate measurements including glenoid inclination, version, implant selection and humeral head subluxation be made on L-CT images 3) Do proposed treatment plans change with the use of L-CT relative to the chosen plans base on C-CT images. The investigators hypothesize L-CT images will be of sufficient image quality for diagnostic purposes, with similar measurements, and treatment outcomes.