A comparable study of the diagnostic performance of orbital ultrasonography and CBCT in patients with suspected orbital floor fractures

Objectives: To compare the diagnostic performance of ultrasonography and CBCT against CT in detecting orbital floor fractures. Methods: A total of 120 orbits with clinical suspicion of isolated orbital floor fractures underwent multislice CT scanning with coronal reconstruction; orbital ultrasonography using a standard machine equipped with a 7- to 10-MHz linear transducer; and CBCT. Patients with severe head and face injuries were not included. The diagnostic performance of ultrasonography and CBCT was reported assuming conventional CT as the imaging method of choice. Results: According to CT findings, fractures of the floor were present in 39 orbits. The sensitivity, specificity, positive-predictive value and negative-predictive value of ultrasonography in detecting orbital floor fractures were 87.2%, 100%, 100% and 94.2%, respectively. The corresponding values for CBCT were 97.4%, 97.5%, 95.0%, and 98.8%, respectively. Areas under the receiver operator characteristics curves of orbital floor fracture detection were 0.94 for ultrasonography and 0.98 for CBCT. Conclusions: When conventional CT cannot be performed in patients with clinically suspected orbital floor fracture and no severe or complex head and face injuries, CBCT could be used in detecting fractures as a reliable surrogate. Because of a lower sensitivity of ultrasonography, however, its use is limited in this regard.