Diagnostic validity of ultrasonography in evaluation of pulmonary thromboembolism

BACKGROUND: Diagnosis of pulmonary embolism (PE) remains difficult due to its nonspecific symptoms and signs. Therefore, many patients die undiagnosed or untreated. We decided to study the sensitivity, specificity, and accuracy of ultrasonography in the diagnosis of pulmonary thromboembolism. MATERIALS AND METHODS: In this prospective study, 77 patients with clinically suspected PE in the emergency department of Isfahan Al-Zahra Hospital were enrolled from September 2011 to September 2012. At first, they were evaluated by thoracic ultrasonography (TUS) and then divided into four groups based on their TUS findings. Multi-slice computed tomography (MSCT) was the reference method in this study performed within 24 h from admission. MSCT scans were interpreted by a radiologist who was unaware of the TUS results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPVs) of thoracic ultrasonography were determined. RESULTS: PE diagnosis was confirmed by MSCT in 25 patients and 54 hypoechoic lesions were detected by TUS with the average size of 16.4 mm × 11.1 mm. In our study, sensitivity, specificity, PPV, NPV, and accuracy of TUS for PE diagnosis were 84%, 94.2%, 87.5%, and 92.5%, respectively. CONCLUSION: TUS is an inexpensive, safe and easily available method for timely diagnosis and treatment of PE in emergency department and its NPV is high for cases with low scores for Wells criteria who had a normal or possible TUS findings. It is also specific in the diagnosis of PE in cases with high scores Wells criteria who have confirmed or probable TUS findings.