Contrast-enhanced ultrasound of the lung; sonographic findings in twenty infectious pneumonia

Reports on pneumonia diagnosis by Contrast-Enhanced Sonography (CEUS) are very scarce because the use of second-generation US contrast agents in the assessment of pulmonary lesions has never been systematically investigated. Recently some authors described typical CEUS patterns in pleuropneumonia. We evaluated CEUS findings in 20 patients with pleuropneumonia and US detected lung lesions. Diagnosis were confirmed by thorax radiographic study (RX) and or Computed Tomography (CT). We identified 4 typical US pneumonia patterns; homogeneous and parenchymatous hypoechoic lesions, hypoechoic lesions with multiple strong echoes, isoechoic lesions with multiple comet tails artifacts, pseudo-nodular or inhomogeneous echo-pattern. CEUS studies were performed using low pressure setting and a second generation contrast medium (Sonovue; Bracco) over a period of 5min. We observed and recorded contrast uptake and time to enhancement. We identified 4 vascular CEUS patterns; no vascular signals, enhanced peri-bronchial vessels, homogeneous enhancement, inhomogeneous enhancement. Results showed no lung lesions enhancement in 10 patients (bronchopneumonia, interstitial pneumonia, abscesses or empyemas). In 2 patients CEUS showed inhomogeneous enhancement (pulmonary infiltrates of lung malignancy). Eight patients showed lung lesions with homogeneous enhancement (small pulmonary infiltrates) or enhanced lung vessels (large “hepatisation“ or “carnefication“ of the lung). No correlation were observed between times to enhancement and US/CEUS patterns. In our experience infectious-pneumonia seems to have multiple CEUS patterns. Larger studies would be useful to support these findings and to evaluate if differential diagnosis with pleural-based lung malignancy is possible by using only CEUS study.