Purpose A rib fracture in an infant usually results from nonaccidental trauma. Chest radiographs (CXR) are currently the standard method for evaluating rib fractures in abused infants. Computed Tomography (CT) is known to be a sensitive method to detect rib fractures. However, to date no studies comparing these two methods in abused infants have been reported. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants.
Methods This retrospective, IRB-approved study included all 11 abused infants identified from 1999-2004 who had rib fractures and both CXR and CT (8 abdomen CTs, 3 chest CTs). CT exams had been performed for clinical indications. Studies were reviewed by two pediatric radiologists to determine the number, locations, and approximate age of the rib fractures. A total of 201 ribs were completely (168) or partially (33) seen on the CT exams, and the matched ribs on CXR were used for the analysis.
Summary of Results The mean age of the patients was 9.5 weeks with a range of 5.3 to 20.6 weeks. There were 4 males and 7 females. Eight infants had both their CXR and CT on the same day, and 3 infants CXRs and CTs were one day apart. Although 127 fractures were visualized by CT, only 76 were seen on CXR (p≤.001). One patient had fractures only seen by CT. There were significantly (p≤.05) more early subacute (86% vs. 14%), subacute (64% vs. 36%), and old fractures (100% vs. 0%) seen by CT than by CXR. There was no significant difference in the number of acute or late subacute fractures seen by CT or CXR. Fractures located anteriorly (73% vs. 27%) and posteriorly (64% vs. 36%) were better seen by CT than by CXR (p≤.01). Significantly (p≤.05) more bilateral fractures were seen by CT (67%) than by CXR (33%). Two non-fracture abnormalities were detected by CT: one pleural effusion and one liver laceration.
Conclusions While the number of patients studied here is small, these findings suggest that CT is better than CXR in visualizing rib fractures in abused infants.