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

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

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

PATIENTS AND METHODS: 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.

RESULTS: 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.

CONCLUSION: 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.