Feasibility of Dark-Field Radiography to Enhance Detection of Nondisplaced Fractures

Background: Many clinically relevant fractures are occult on conventional radiographs and therefore challenging to diagnose reliably. X-ray dark -field radiography is a developing method that uses x-ray scattering as an additional signal source. Purpose: To investigate whether x-ray dark -field radiography enhances the depiction of radiographically occult fractures in an experimental model compared with attenuation -based radiography alone and whether the directional dependence of dark -field signal impacts observer ratings. Materials and Methods: Four porcine loin ribs had nondisplaced fractures experimentally introduced. Microstructural changes were visually verified using high -spatial -resolution three-dimensional micro -CT. X-ray dark -field radiographs were obtained before and after fracture, with the before -fracture scans serving as control images. The presence of a fracture was scored by three observers using a six -point scale (6, surely; 5, very likely; 4, likely; 3, unlikely; 2, very unlikely; and 1, certainly not). Differences between scores based on attenuation radiographs alone (n = 96) and based on combined attenuation and dark -field radiographs (n = 96) were evaluated by using the DeLong method to compare areas under the receiver operating characteristic curve. The impact of the dark -field signal directional sensitivity on observer ratings was evaluated using the Wilcoxon test. The dark -field data were split into four groups (24 images per group) according to their sensitivity orientation and tested against each other. Musculoskeletal dark -field radiography was further demonstrated on human finger and foot specimens. Results: The addition of dark -field radiographs was found to increase the area under the receiver operating characteristic curve to 1 compared with an area under the receiver operating characteristic curve of 0.87 (95% CI: 0.80, 0.94) using attenuation -based radiographs alone (P < .001). There were similar observer ratings for the four different dark -field sensitivity orientations (P = .16-.65 between the groups). Conclusion: These results suggested that the inclusion of dark -field radiography has the potential to help enhance the detection of nondisplaced fractures compared with attenuation -based radiography alone. (c) RSNA, 2024