Gantry-Free High-Resolution Cone-Beam CT: Efficacy for Distal Radius and Scaphoid Fracture Detection and Characterization

Abstract

Gantry-free cone-beam CT (CBCT) allows for comfortable patient positioning due to an open scanner architecture. Since CBCT without gantry is not yet established for clinical wrist trauma imaging, this study's aim was to investigate its diagnostic value in the preoperative workup of patients with distal radius and scaphoid fractures. Within a 12-month period, 113 patients with severe wrist trauma underwent both radiography and CBCT with the same gantry-free multi-use scanner before surgery. Two radiologists retrospectively analyzed all datasets for the morphology of distal radius (n=95) and scaphoid fractures (n=20). In all 115 wrists (two bilateral injuries), surgical reports served as the standard of reference. While accuracy for distal radius fractures was comparable among CBCT and radiographs, the former was superior with regard to scaphoid fractures (Reader 1: 100.0% vs. 75.0%; Reader 2: 100.0% vs. 65.0%). Accuracy for multi-fragmentary radius injuries (100.0% vs. 90.5%; 100.0% vs. 93.7%), and articular affliction (99.0% vs. 84.2%; 100.0% vs. 83.2%) was also higher in CBCT. Regarding scaphoid fractures, CBCT proved superior for diagnosis of proximal pole or waist involvement (100.0% vs. 70.0%; 100.0% vs. 65.0%) and comminuted patterns (100.0% vs. 70.0%; 100.0% vs. 75.0%). Median effective dose of CBCT was as low as 3.65 µSv compared with 0.16 µSv for standard radiography. Gantry-free CBCT allows for excellent diagnostic accuracy in the assessment of distal radius and scaphoid fracture morphology. Even in patients with limited mobility, very low radiation dose is sufficient to maintain high image quality.