[Diagnosis of pulmonary embolism by transthoracic sonography. Sono-morphologic characterization of pulmonary lesions and comparison with spiral computed tomography]

Abstract

Background and objective: Pulmonary embolism often extends to pleural surfaces, resulting in pleural-based parenchymal lesions. This study was carried out in order to evaluate the clinical value of transthoracic sonography (TS) for the diagnosis of pulmonary embolism.

Patients and methods: A prospective study was performed in 45 patients (27 men, 18 women; mean age: 63.4 years; range: 24-88 years) with suspected pulmonary embolism. Transthoracic sonography was performed in all patients. In addition, helical computed tomography (CT) was carried out in 40 patients. Other diagnostic procedures included the estimation of D-dimeres, echocardiography, venous duplex sonography of the legs and ventilation/perfusion scanning. The diagnosis of pulmonary embolism was accepted when an embolus was detected on CT or as a conclusive result of the other investigations.

Results: Pulmonary embolism was established in 33 patients. Peripheral parenchymal lesions suspicious of pulmonary embolism were detected by transthoracic sonography in 26 patients (79%). In seven patients with central pulmonary embolism diagnosed by CT, no peripheral lesions could be detected by sonography. One patient with sonographic signs of pulmonary embolism had a diffuse bronchogenic adenocarcinoma which was diagnosed on autopsy. The sensitivity of transthoracic sonography (computed tomography) for pulmonary embolism was 79% (76%) and the specificity 92% (100%). The positive and negative predictive values of transthoracic sonography for the detection of pulmonary embolism were 96% and 61% (100% and 61%), respectively. The accuracy was 82% (82%).

Conclusions: A substantial number of pulmonary emboli involve the peripheral lung areas. Transthoracic sonography is a non-invasive technique for diagnosing such parenchymal alterations and may serve as an alternative method in the diagnosis of pulmonary embolism.