Diagnostic value and limitations of CT in detecting rib fractures and analysis of missed rib fractures: a study based on early CT and follow-up CT as the reference standard

To evaluate the value and limitations of computed tomography (CT) diagnosis of rib fractures, and to discuss the characteristics of missed rib fractures.One hundred and sixty chest trauma patients who underwent both early CT (within 48 h) and follow-up CT (14 days later) were enrolled. For early CT examinations, the diagnosis of rib fractures was divided into routine assessment and verification assessment. The detection rates of rib fractures in both patterns were calculated, and the characteristics of missed rib fractures were analysed, based on the imaging results of the twice CT examinations as the reference standard.A total of 584 fracture sites were confirmed. The overall detection rate of rib fractures in the routine assessment method was 72.4%. In the verification assessment, the detection rates of rib fractures of four observation strategies (axial images, multiplanar reconstruction [MPR], axial images + volume reconstruction [VR] and MPR + VR) were 76.2%, 79.1%, 78.6%, 80.8%, respectively. The incidence of occult fractures was 19.2% (112/584). In both assessment methods, the detection rates of rib fractures at the costochondral junction were the lowest (60%, 65%, respectively); the detection rates ranged from 63.6% to 74.7% for non-displaced rib fractures, but 100% for displaced rib fractures. Most (78.9%) missed rib fractures were accompanied by visible fractures on the same or adjacent first to second rib.Most missed rib fractures are occult on early CT, which is attributable to the limitations of the CT technique. The number of displaced rib fractures on early CT is a more stable and reliable clinical indicator.