Non-Contrast Chest CT Scans In Detection Of Pulmonary Thromboembolism

Background:Pulmonary embolism (PE) is the third most common acute cardiovascular disease after myocardial infarction and stroke and results in thousands of deaths each year because it often goes undetected. This study, aime to evaluate the role of non–contrast MSCT in detection of pulmonary embolism. Methods: One hundered patients requested for CT pulmonary angiography (pulmonary CTA) clinically evaluated according to revised Geneva scoring system undergone non-contrast and contrast-enhanced CT images of the chest and were reviewed separately. The average CT attenuation differences between the high attenuation clots and pulmonary arteries were computed. Findings in the non-contrast images were correlated with the contrast-enhanced images. Results: Twenty-six of 100 patients were positive for PE in CTAs. Mean age (± SD) was 56.73 (± 9.11) years, 17 (65.4%) were females, Geneva scoring revealed low, intermediate, high propablity(2%, 7%, and 17%) respectively. Of these 26 patients, 13 were positive for the hyperdense lumen sign in the non-contrast CT images with high, intermediate and low revised Geneva score 10(76%), 3 (23%), 0 (0%) respectively. The hyperdense lumen sign has an over-all sensitivity of 50 %, specificity of 98.6%. The other 13 patients; ten of them had more than one indirect sign. The most common indirect sign revealed high specificity 91% and statistical significant is the peripheral wedged shaped opacities. Conclusion: Non-contrast chest CT scans have good role in evaluation of PE through detection the hyperdense lumen sign that is a good indicator of acute pulmonary thromboembolism particularly in cases involving the central pulmonary arteries or peripheral wedge shaped opacity as useful indirect sign.