Study objectives: Despite the widespread use of lung
scanning and angiography, pulmonary embolisms (PEs) remain undiagnosed
in the majority of patients, suggesting the need for alternative
diagnostic approaches. The present study investigates the clinical
utility of transthoracic sonography (TS) for the diagnosis of PE and
compares the data obtained with the technique to those obtained by
spiral CT (sCT) scanning.
Design: This prospective
study was performed using 69 patients with suspected PEs. TS was
performed in all patients. In addition, sCT scanning was carried out in
62 patients. Other diagnostic procedures included the estimation of
d-dimers, echocardiography, venous duplex sonography of the legs,
pulmonary angiography, and ventilation/perfusion scanning. The
diagnosis of PE was accepted when there was a conclusive result of
these investigations or when an embolus could be visualized on a CT
Setting: The Department of Pneumology in
Friedrich-Schiller-University Hospital (Jena, Germany).
Patients: Sixty-nine patients (27 women and 42 men) with
Results: A diagnosis of PE was
established in 44 patients. Ninety-one peripheral parenchymal lesions
(mean, 2.6 lesions per patient; range 1 to 9 lesions per patient) that
are associated with PE were detected by TS in 35 patients (80%).
Multiple, triangular, hypoechoic, and pleural-based parenchymal lesions
with a localized and/or basal effusion were typical of the PEs as shown
by TS. In nine patients with central PEs that had been diagnosed by CT
scanning, no peripheral lesions could be detected by sonography. One
patient with sonographic signs of PEs had a diffuse bronchogenic
adenocarcinoma that was diagnosed at autopsy. In another patient with
parenchymal lesions, pneumonia was diagnosed by CT scanning. The
sensitivity of TS for detecting PEs was 80% (sensitivity of CT
scanning, 82%), and the specificity of TS for detecting pulmonary
lesions was 92% (specificity of CT scanning, 100%). The positive and
negative predictive values of TS for the detection of PEs were 95% and
72%, respectively (positive predictive value for CT scanning, 100%;
negative predictive value for CT scanning, 77%). The accuracy of TS
was 84% (accuracy of CT scanning, 89%).
TS is a noninvasive technique that is used for diagnosing parenchymal
alterations, and it may serve as an additional method in the strategy
for diagnosing PE.