The validity of hyperdense lumen sign in non-contrast chest CT scans in the detection of pulmonary thromboembolism

Abstract

It is possible to identify high-attenuation clots in pulmonary thromboembolism using non-contrast computed tomography (CT) of the chest. Such detection may be crucial for timely initiation of appropriate therapy. This study was undertaken to determine the validity of the hyperdense lumen (high-attenuation clot) sign in unenhanced chest CT in detecting pulmonary thromboembolism. Non-contrast and contrast-enhanced CT images of the chest of 121 patients who had undergone standard CT pulmonary angiography (pulmonary CTA) were reviewed separately. The absence or presence of luminal hyperdensities within the pulmonary arteries in the non-contrast images was determined. 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. Twenty-five patients were positive for pulmonary thromboembolism in the pulmonary CTAs. Of these 25 patients, nine were positive for the hyperdense lumen sign in the non-contrast CT images. The hyperdense lumen sign has an over-all sensitivity of 36.0%, specificity of 99.0%, PPV of 90.0%, and NPV of 85.6% (κ=0.449; P-value<0.001). In detecting central thromboembolism, the sensitivity, specificity, PPV, and NPV of this sign were 66.7, 99.1, 88.9, and 96.4%, respectively (κ=0.740; P-value<0.001). The sign was less sensitive in peripheral thromboembolism (κ=0.358; P-value<0.001). The mean (±SD) attenuation difference between the clot and pulmonary blood pool was 22.76 (±4.20) HU (P-value<0.001). The hyperdense lumen sign is a useful indicator of acute pulmonary thromboembolism in non-contrast chest CT scans particularly in cases involving the central pulmonary arteries.

Common Postmortem Computed Tomography Findings Following Atraumatic Death: Differentiation between Normal Postmortem Changes and Pathologic Lesions

“…Although pulmonary thrombosis varies in density and form, it is distinguishable from hypostasis. The key features suggesting pulmonary thrombus are a blood clot with a non-fluid-fluid level and hyperdense cast formation occluding the pulmonary artery ( 34 35 36 ). However, this standard should not be applied when the posture of the cadaver is changed.…”

The hyperdense lumen sign: the tale of the elusive pulmonary embolism

“…However, this finding is rarely observed on unenhanced CT examinations, even when PE is present. There are more well-recognised indirect signs of acute PE, which are neither sensitive nor specific, including pulmonary arterial dilation, pleural effusion, regional oligaemia, subpleural pulmonary consolidations and/or airspace opacities 1. In our case, the patient had a dilated main pulmonary artery (figure 2), suggestive of pulmonary hypertension and evidence of right heart strain with cor pulmonale confirmed on echocardiogram.…”

“…We present a case of the hyperdense lumen sign, a rare finding that has previously been reported to correlate with the presence of acute PE on unenhanced CT with a specificity of 99% 1. The hyperdense appearance of acute thrombus is caused by increased concentration of haemoglobin due to decreased water content and varies based on the patient's haematocrit level and the age of the clot 2.…”

Cerebral Infarction with Pulmonary Thromboembolism Due to Immobilization

“…Since the present patient had not been tested for pulmonary thromboembolism prior to this admission, it is possible she was suffering from chronic thromboembolic pulmonary hypertension before the onset of cerebral infarction. However, the presence of this condition is unlikely, as both a positive McConnell's sign (12) and high-attenuation clots in the pulmonary arteries on non-contrast CT (16) were observed, indicating acute pulmonary thromboembolism. This is also consistent with her self-report of performing normal activities of daily living until three days before admission.…”