Inclusion Criteria:  1. Subjects (males and/or females) must be ≥ 18 years of age  2. Subjects are willing and able to provide written informed consent for collection of the data; if a patient has already completed and performed the calibrated CT-scans as per standard clinical practice, the subject may be contacted to offer participation in the study.  3. Adult patients who will undergo noncontrast CT scanning of the shoulder as part of routine preoperative planning for shoulder arthroplasty will be eligible to participate in the study and receive a calibrated CT scan of the shoulder. The decision to undergo CT scan will be made independently of study participation; only patients who require a CT scan of the shoulder for clinically necessary reasons are eligible to participate.  Exclusion Criteria:  1. Pregnancy or lactation; 2. Subjects who have fracture of the affected shoulder; 3. Subjects who have had prior surgery on the affected shoulder that resulted in metal implants, including but not limited to: Partial or total shoulder joint replacement; Open reduction internal fixation of fracture; Prior rotator cuff repair with metal implants; 4. Local or systemic infection; 5. Persistent acute or chronic osteomyelitis; 6. Focal vascular or neurologic diseases affecting the concerned limb; 7. Metabolic disorders or systemic diseases that substantially affect bone quality, including the following: Renal osteodystrophy Osteoporosis Osteomalacia Osteopetrosis 8. Bone tumors involving the shoulder girdle; 9. Local or disseminated neoplastic diseases; 10. Severe deformity including malunion, nonunion, excessive bone loss that would result in improper virtual implant positioning;