The accuracy of non-contrast chest computed tomographic Scan in the detection of pulmonary thromboembolism

Background Pulmonary embolism (PE) is a critical chest disease resulting in high mortality rates if undetected. This study aimed to evaluate the role of noncontrast multislice computed tomography in the detection of PE. Patients and methods One hundred patients requested for computed tomography (CT) pulmonary angiography and underwent noncontrast and contrast‑enhanced CT images of the chest, which were reviewed separately. The average CT attenuation differences between the high‑attenuation clots and pulmonary arteries were computed. Findings in the noncontrast images were correlated with the contrast‑enhanced images. Results Twenty‑six of 100 patients were positive for PE in computed tomography angiography; the mean age (±SD) was 56.73 (±9.11) years, and 17 (65.4%) were female individuals. The hyperdense lumen sign has an overall sensitivity of 50% and specificity of 98.6%. As for the other 13 patients, 10 of them had more than one indirect sign. The peripheral wedge‑shaped opacity was the most common indirect sign that revealed high specificity (91%) and was statistically significant. Conclusion Noncontrast chest CT scan has a good role in the evaluation of PE through detection of the hyperdense lumen sign, which is a good indicator of acute pulmonary thromboembolism, particularly in cases involving the central pulmonary arteries or peripheral wedge‑shaped opacity, as a useful indirect sign.