Pros and cons of rib unfolding software: a reliability and reproducibility study on trauma patients

BACKGROUND: Examination of all 24 ribs on axial computed tomography (CT) slices might become a leeway and rib fractures (RF) may easily overlook in daily practice. Rib unfolding (RU), a computer-assisted software, that promises rapid assessment of the ribs in a two-dimensional plan, was developed to facilitate rib evaluation. We aimed to evaluate the reliability and reproducibility of RU software for RF detection on CT and to determine the accelerating effect to determine any drawback of RU application. METHODS: Fifty-one patients with thoracic trauma formed the sample to be assessed by the observers. The characterization and distribution of RFs on CT images in this sample were recorded independently by the non-observers. Regarding the presence or absence of RF, CT images were assessed blindedly by two radiologists with 5 years (observer-A) and 18 years (observer-B) of experience in thoracic radiology. Each observer assessed the axial CT and RU images on different days under non-observer supervision. RESULTS: A total of 113 RFs were detected in 22 patients. The mean evaluation time for the axial CT images was 146.64 s for observer-A and 119.29 s for observer-B. The mean evaluation time for RU images was 66.44 s for observer-A and 32.66 s for observer-B. A statistically significant decrease was observed between the evaluation periods of observer-A and observer-B with RU software compared to the axial CT image assessment (p<0.001). The inter-observer κ value was 0.638, while the intra-observer results showed moderate (κ: 0.441) and good (κ: 0.752) reproducibility comparing the RU and axial CT assessments. Observer-A detected 47.05% non-displaced fractures, 48.93% minimally displaced (≤2 mm) fractures, and 38.77% displaced fractures on RU images (p=0.009). Observer-B detected 23.52% non-displaced fractures, 57.44% minimally displaced (≤2 mm) fractures, and 48.97% displaced fractures on RU images (p=0.045). CONCLUSION: RU software accelerates fracture evaluation, while it has drawbacks including low sensitivity in fracture detection, false negativity, and underestimation of displacement.