Evaluation of a two-image technique consisting of an axial and a coronal image generated by using the rib-flattening application: effect on reading time and diagnostic validity

Background/aim: When reading a chest CT, a radiologist needs to evaluate each rib one by one due to complex curvy shape, which makes reporting a tiresome and time-consuming task. A new curved planar reformat application that flattens ribs on a single plane may find a place in the radiology reporting room. This study aimed to evaluate the effect of a two-image set created by using the rib-flattening application on the performance of a radiologist in detecting sclerotic rib lesions in cancer patients. Materials and methods: The local Institutional Review Board approved this retrospective study. Two radiologists with different experience levels reviewed chest CT examinations of 106 patients (76 men, 30 women). We divided the patients into group A (n = 54), reviewed by a standard method, and group B (n = 52), reviewed by a standard method and the two-image set created on the rib-flattening application. Reading times, validity indices, and agreement levels with reference data were evaluated for both readers. Results: The median reading time of the junior examiner significantly decreased with the rib-flattening method (160.5 s vs. 70.0 s; P < 0.001). Diagnostic indices of the senior reader were improved significantly at per patient level (group A, AUC: 0.867; group B, AUC: 0.982; P = 0.046). The new method showed better agreement levels (kappa: 0.69 to 0.96) than the general method (kappa: 0.53 to 0.91). Conclusion: Based on improved agreement levels, reading times, and diagnostic validity indices we conclude that a two-image set consisting of an axial and a coronal flattened-rib image may be used in conjunction with an ordinary exam.