Diagnostic ultrasound ( PDFDrive )

CHAPTER 50 The Pediatric Chest 1711
A B C
D
E
F
FIG. 50.16 Septations in Pleural Space Are Seen Better on Sonograms Than Computed Tomography (CT) Scans. (A) Chest radiograph
shows opaciied left hemithorax. (B) Sonogram shows a septated luid collection. (C) CT scan shows pleural luid, but the septa are not well visualized.
(D) In another child with cystic ibrosis and lung transplant, sonogram shows septated pleural luid on the right side, in addition to (E) echogenic
pleural luid with few septations on the left side. (F) CT scan shows bilateral pleural luid, but septations at the right base are not well
visualized.
have longer hospital stays and beneit from intrapleural ibrinolytic
therapy or surgical procedures. 11
Lung Abscess Versus Empyema
Lung abscess adjacent to the chest wall or to an acoustic window
such as the liver or spleen usually appears as a complex collection
with luid-debris levels and septations just like an empyema.
Abscesses and empyemas usually exhibit diferent types of motion
when visualized by ultrasound. An abscess demonstrates expansion
of the entire circumference with inspiration, whereas with
an empyema, only the internal wall adjacent to the lung shows
slight motion. Lung abscesses may be diicult to diferentiate
from empyema when the empyema contains multiple, loculated
air collections caused by thoracentesis. Air-luid collections move
with patient repositioning, which can aid in distinguishing
empyema from abscess (Figs. 50.18 and 50.19).
LUNG PARENCHYMAL DISORDERS
Pneumonia
Consolidated lung is hypoechoic relative to the highly relective,
air-illed, normal surrounding lung. Consolidated lung echogenicity
is similar to that of liver (Fig. 50.20), but sonographic
air bronchograms diferentiate it from liver. Strong, nonpulsatile,
branching, linear echoes produced by air-illed bronchi converge
toward the root of the lung. he linear pattern of bright echoes
is observed when scanning parallel to the long axis of the bronchi
(Fig. 50.21). When the scanning is done at more acute angles,
scattered echoes of variable lengths produced by the sonographic
air bronchograms are observed (Fig. 50.22). If there is adjacent
pleural luid, the hypoechoic consolidated lung can be diferentiated
from the hypoechoic-to-anechoic pleural efusion by
identiication of these sonographic air bronchograms.
Round Pneumonia
Round pneumonia is more common in children younger than
8 years, but 15% occur between 8 and 12 years. 12 Young children
do not have well-formed pores of Kohn and channels of Lambert
for collateral air circulation. he inlammation spreads centrifugally
as the strands of ibrin usually spread during the red hepatization
phase of pneumonia through the pores of Kohn and channels
of Lambert. 13 Owing to underdevelopment of these collateral
circulations, the advancing front is sharply demarcated from the
unafected lung parenchyma and causes a focal round mass like
pneumonia that mimics a posterior mediastinal mass on the
radiograph of the chest. Most round pneumonias are posteriorly
located and in lower lobes.