Chest non‑contrasted computed tomography in detecting acute pulmonary thromboembolism: A single‑center retrospective study.

The object of the study was to evaluate comprehensively the value of chest non-contrasted CT (NC-CT) in detecting acute pulmonary thromboembolism (APE). All patients were categorized into two groups: i) With APE; and ii) without APE based on clinical diagnosis. Using the clot distribution on computed tomography pulmonary angiography (CTPA), APE was divided into central and peripheral APE. Imaging features including hyperdense lumen sign and peripheral wedge-shaped opacity on chest NC-CT were evaluated. The attenuation value of peripheral wedge-shaped opacity on NC-CT was compared between patients with and without APE. Among the 273 patients, there were 110 patients with APE, 49 patients with central APE and 61 patients with peripheral APE and 163 patients without APE. The hyperdense lumen sign had a sensitivity of 30.0% and a specificity of 97.6% in detecting APE. The sensitivity and specificity of hyperdense lumen sign in detecting central APE were 57.1 and 97.6%, respectively, while the relevant percentages in detecting peripheral APE were 8.2 and 97.6%, respectively. The mean attenuation value of peripheral wedge-shaped opacity in patients with APE was significantly lower than that in patients without APE (P<0.001). Regarding the age-adjusted D-dimer, there was a decrease of eight D-dimer positive cases for patients >50 years old without APE, confirmed by CTPA. In conclusion, chest NC-CT cannot be used as an alternative modality for CTPA in diagnosing APE, however, the hyperdense lumen sign had high specificity in the diagnosis of central APE. Patients with this symptom and increased D-dimer may not require further CTPA. The lower attenuation value of peripheral wedge-shaped opacity on NC-CT suggested APE, and CTPA confirmation was required. The age-adjusted D-dimer had higher specificity in excluding APE.