Acute pulmonary thromboembolism in emergency room: gray-scale versus color doppler ultrasound evaluation

Pulmonary thromboembolism (PTE) remains under-diagnosed fatal disease at emergency units suggesting the need for alternative, easy, and noninvasive bedside diagnostic approaches.

To determine the diagnostic role of gray-scale and color Doppler transthoracic ultrasonography (TUS) in patients with PTE.

Blinded to 64 multi-detectors CT pulmonary angiography (MDCTPA) examination as a gold standard, 60 patients with clinically suspected PTE underwent gray-scale and then color Doppler TUS examination. Results were compared and diagnostic accuracy of TUS was assessed.

Forty patients proved to have PTE by MDCTPA. TUS showed typical lesions in 33 patients with the mean of 2 lesions per patient. Most lesions were hypoechoic, wedge- shaped, and pleural- based and the majority (80%) was located in the lower lobes. Consolidation with little perfusion was detected by Color Doppler ultrasound in 97% of lesions. Isolated central PTE was significantly higher in TUS negative patients. For gray -scale TUS, sensitivity, specificity, positive and negative predictive values and accuracy were 82%, 90%, 94%, 72%, and 85%. Meanwhile the sensitivity, specificity, positive and negative predictive values and accuracy of color Doppler TUS were 80%, 95%, 97%, 70% and 87%, respectively.

TUS is a reliable diagnostic bedside test for PTE in critically ill and immobile patients. Adding color Doppler to gray-scale TUS increases the specificity and accuracy and consequently the confidence in the diagnosis of peripheral pulmonary infarctions and differentiates them from other pulmonary lesions that allow initiation of anticoagulants.