Chest Sonography in the diagnosis of pulmonary embolism: A comparison with MRI angiography and ventilation perfusion scintigraphy

Aim: To compare the diagnostic performance of chest sonography, MRI angiography and ventilation/perfusion intigraphy in pulmonary embolism (PE). Method: In a prospective clinical study, 55 patients (41 women, 14 men, age 23-91 years) with clinical signs of PE were investigated within 48 hours of the onset of symptoms. The final diagnosis was made by MRI angiography (reference method). Results: PE was diagnosed in a total of 36 patients. Chest sonography revealed rounded or wedge-shaped hypoechoic lesions in 30 patients. On ventilation/perfusion (V/P) scintigraphy, 41 patients had positive V/P scans, but only 23 were of high probability. Chest ultrasound had a positive predictive value of 97% to diagnose PE. The sensitivity, specificity, the negative predictive value and accuracy were 81%, 84%, 84% and 82%, respectively. As 18 patients had inconclusive scans, the diagnostic performance of ventilation/perfusion scintigraphy was poor. The positive predictive value, sensitivity and specificity were 58%, 42% and 91%, respectively. Patients in whom PE was excluded mainly suffered from congestive heart failure, bronchopulmonary infections or pulmonary hypertension. Conclusion: A negative sonographic study cannot rule out PE with certainty. However, a chest sonography is of acceptable diagnostic value in patients with suspected PE and may be used as an adjunct or guide to more established methods.