Pleural Effusion

Fig. 15.14 A 40-year-old man with malignant mesothelioma.

a Chest radiograph shows encasement of the right lung.

b and c Right lateral intercostal scan shows extensive hypoechoic tumor encasement (TU) of the lung (LU). L = liver.

■ Pleural Effusion

Pleural effusion is by far the most common space-occupying process occurring in the pleural cavity ( 15.7). The value of ultrasound lies in its ability to distinguish an effusion from other diffuse lung opacities that are seen on radiographs. Ultrasound is superior to conventional chest radiographs in both sensitivity and specificity. Free effusion volumes as small as 5 mL can be identified. Sonography cannot de-

tect a loculated interlobar effusion or localized mediastinal fluid.

A pleural effusion displays characteristic sonographic features with regard to its location ( 15.7a,b,d–f) (unilateral/bilateral), extent ( 15.7c,g–i), echogenicity ( 15.7j), and the presence of septations ( 15.7i,k,l), depending on the cause of the effusion (Table 15.5). Goecke et al.9 described a volumetry technique

that has proved useful for the sonographic assessment of effusion volume (Fig.15.15).

The etiological classification of a pleural effusion is based on clinical presentation, sonographic findings, and the result of percutaneous aspiration. Table 15.6 summarizes the differential diagnosis of pleural effusion and the characteristic ultrasound findings.

15

Pleura and Chest Wall

Fig. 15.15 Diagram showing the technique of pleural effusion volumetry.9

Table 15.6 Differential diagnosis of pleural effusion

NHL = Non-Hodgkin lymphoma.

15.7 Imaging Appearances of Pleural Effusion

Basal e usion, inflammatory

a–c Radiographic and sonographic appearances of pleural e usion.

a Chest radiograph shows elevation of the diaphragm in a 47-year-old woman.

b Right lateral intercostal scan demonstrates a subpulmonic e usion as the cause of the radiographic sign. PE = pleural e usion; L = liver; LU = lung.

c No e usion is visible in the conventional radiograph. Ultrasound reveals a small e usion on the left side. D = diaphragm; LU = lung.

d–f A 48-year-old man with pleurisy.

d CT shows a localized fluid collection along the pleural wall.

e and f Ultrasound scans over a 6-month period document resolution of the pleural e usion (PE; E) in response to antibiotic therapy. LU = lung.

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Pleural Effusion

Fig. 15.16 A 54-year-old man with congestive heart failure.

a Chest radiograph shows pronounced cardiomegaly and possible pleural effusion.

Exudative Effusion

In principle, even protein-rich pleural effusions may appear anechoic. They consist mainly of parainfectious effusions (e. g., due to pleurisy,

b Right lateral intercostal scan shows an indeterminate hypoechoic mass (?).

pneumonia, polyserositis, or tuberculosis) and malignant effusions (e. g., due to bronchial or mammary carcinoma).

c Conspicuous flow patterns at color Doppler confirm that the mass is an enlarged right heart. LU = lung.

Echogenic Effusion

Benign Effusion

Malignant Effusion

Fig. 15.17

c and d Bronchial carcinoma in a 60-year-old man.

c Chest radiograph shows almost complete opacification of the right lung.

d Right lateral intercostal scan shows a nonhomogeneous hyperechoic structure formed by echoes that move with respiration. Pleural fluid aspiration confirmed a hematothorax. L = liver.

Malignant Effusion

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Pleural Effusion

Fig. 15.18 Metastatic mucus-forming ovarian carcinoma in a 74-year-old woman.

a Chest radiograph shows almost complete opacification of the right lung.

Fig. 15.19 Bronchial carcinoma in a 63-year-old man. SL = superior lobe; IL = inferior lobe.

a Chest radiograph shows complete opacification of the left lung.

b and c Right anterior intercostal scan shows a nonhomogeneous echogenic mass containing faint echoes that move with respiration. Aspiration yielded mucoid material from an expansile tumor metastatic to ovarian carcinoma. COR = heart; VC = vena cava; L = liver; AO = aorta.

b and c Left lateral intercostal scan (b) and a second scan perpendicular to the first (c) demonstrate a hyperechoic effusion with complete atelectasis of the superior lobe (SL) and inferior lobe (IL). The inferior lobe contains a liquid mass consistent with necrotic liquefaction.