Minor Blunt Thoracic Trauma in the Emergency Department: Sensitivity and Specificity of Chest Ultralow-Dose Computed Tomography Compared With Conventional Radiography

Abstract

Study objective: To evaluate the diagnostic performance of chest ultralow-dose computed tomography (CT) compared with chest radiograph for minor blunt thoracic trauma.

Methods: One hundred sixty patients with minor blunt thoracic trauma were evaluated first by chest radiograph and subsequently with a double-acquisition nonenhanced chest CT protocol: reference CT and ultralow-dose CT with iterative reconstruction. Two study radiologists independently assessed injuries with a structured report and subjective image quality and calculated certainty of diagnostic confidence level.

Results: Ultralow-dose CT had a sensitivity and specificity of 100% compared with reference CT in the detection of injuries (187 lesions) in 104 patients. Chest radiograph detected abnormalities in 82 patients (79% of the population), with lower sensitivity and specificity compared with ultralow-dose CT (P<.05). Despite an only fair interobserver agreement for ultralow-dose CT image quality (κ=0.26), the diagnostic confidence level was certain for 95.6% of patients (chest radiograph=79.3%). Ultralow-dose CT effective dose (0.203 mSv [SD 0.029 mSv]) was similar (P=.14) to that of chest radiograph (0.175 mSv [SD 0.155 mSv]) and significantly less (P<.001) than that of reference CT (1.193 mSv [SD 0.459 mSv]).

Conclusion: Ultralow-dose CT with iterative reconstruction conveyed a radiation dose similar to that of chest radiograph and was more reliable than a radiographic study for minor blunt thoracic trauma assessment. Radiologists, regardless of experience with ultralow-dose CT, were more confident with chest ultralow-dose CT than chest radiograph.