Diagnostic accuracy of the inverted grayscale rib series for detection of rib fracture in minor chest trauma.

Study Objective: To assess whether inverted grayscale rib series, used alone or as an additional imaging modality, improves diagnostic accuracy of rib fractures of emergency medicine (EM) residents in minor chest trauma.

Methods: Twenty readers, including 5 junior and 5 senior EM residents and 10 fourth-year medical students, independently reviewed 110 patients' radiographs during 3 sessions. Session 1 used conventional grayscale rib series, session 2 used inverted grayscale rib series, and session 3 used both conventional and inverted grayscale images. The McNemar test was used to compare the sensitivities and specificities of the diagnostic methods, and to compare their sensitivities and specificities for detecting more than 3 rib fractures. Interobserver agreement was assessed using Cohen κ analysis.

Results: For senior EM residents, there was no difference in sensitivity (P = .283) and accuracy (P = .888) between conventional rib series and the double-modality method. For junior EM residents and medical students, the double modality offered higher diagnostic sensitivity (P < .001, P = .001) and accuracy (P = .006, P = .002) than did conventional radiography. In cases with more than 3 rib fractures, who required specialist trauma care, the double modality provided greater sensitivity and accuracy among junior EM residents (P = .035 and P = .035, respectively) and medical students (P = .010, P = .010) than did conventional radiography.

Conclusions: In the diagnosis of rib fractures, the combined use of conventional and inverted grayscale rib series increases the diagnostic accuracy of less biased readers by conventional grayscale image like junior EM residents and medical students.