Diagnostic ultrasound ( PDFDrive )

1716 PART V Pediatric Sonography
A
B
FIG. 50.24 Atelectasis From Foreign Body. (A) Chest radiograph shows air bronchograms in opaciied right side of chest with shift of the
heart to the right, indicating volume loss. (B) Transverse sonogram through liver shows no luid in chest. Multiple air bronchograms (arrow) are
visible within collapsed lung. At endoscopy, foreign body was found in right main stem bronchus. (With permission from Seibert RW, Seibert JJ,
Williamson SL. The opaque chest: when to suspect a bronchial foreign body. Pediatr Radiol. 1986;16[3]:193-196. 76 )
bronchial obstruction and compromised pulmonary artery supply
as a result of inlammation. Inferior pulmonary ligament artery
and phrenic artery normally supply inferomedial and diaphragmatic
visceral pleura, respectively. hese normal arteries may
become parasitized to supply the infected portion of a lower
lobe if the normal pulmonary arterial supply is compromised.
he intralobar sequestered lung is typically present in the lower
lobes and is enclosed by the visceral pleura of the parent lung.
Ultrasound may show a hypoechoic mass in the lower lobe (Fig.
50.25). Color Doppler can demonstrate a systemic vessel supplying
the hypoechoic mass in both extralobar and intralobar
sequestration.
Bronchopulmonary Foregut Malformation
Bronchogenic cysts or bronchopulmonary foregut malformations
32 may be identiied by chest ultrasound if they are adjacent
to the chest wall (Fig. 50.26).
DIAPHRAGM DISORDERS
Sonography is particularly valuable in evaluating a paradiaphragmatic
lesion, which may be a diaphragm eventration, 33
a diaphragmatic hernia (Fig. 50.27), a subphrenic abscess, 34,35
or an intrathoracic kidney. 36 hese abnormalities frequently
are associated with respiratory compromise, making bedside,
portable sonography the study of choice. Less common diaphragmatic
masses detected by sonography include hemangioma, 37
primitive neuroectodermal tumor, and primary embryonal
rhabdomyosarcoma. 38-40
Ultrasound is the bedside examination of choice for evaluation
of suspected diaphragmatic motion abnormalities. Comparison
of hemidiaphragm motion can be observed by placing the
transducer in the subxiphoid position in a transverse orientation,
angled upward toward the posterior lealets of the hemidiaphragms.
Such comparison can be done with transverse sonographic
scanning in infants (Video 50.2), but in older children
(Video 50.3), unilateral sagittal scanning of each diaphragm is
necessary. A comparison of the maximal excursion of the diaphragm
for each side using real-time ultrasound is more accurate
than luoroscopy in demonstrating diaphragmatic movement
abnormality. 41 In the artiicially ventilated patient, the respirator
must be disconnected for 5 to 10 seconds to observe unassisted
respiration. With paralysis, there is absent or paradoxical motion
on one side and exaggerated excursions on the opposite side.
Diaphragm paralysis is a frequent concern ater cardiac surgery 42
(Video 50.4). Severe eventration and a diaphragmatic hernia
may also show paradoxical motion. During real-time evaluation
of diaphragm motion, 43 M-mode sonography can also be used
in assessment of diaphragm function 44 (Figs. 50.28 and 50.29).
Sonography can demonstrate rupture of the diaphragm 45
(Fig. 50.30).
VASCULAR DISORDERS
Vascular Thrombosis
he normal thymus is an excellent acoustic window to view
normal mediastinal structures and mediastinal masses. he
thymus is anterior to the great vessels and extends inferiorly to
the upper portion of the heart. he great vessels, including the
SVC, aorta, and pulmonary artery, are well imaged through the
thymus. hese vessels are more conspicuous with color Doppler
ultrasound (Fig. 50.31). he let brachiocephalic vein courses
Text continued on p. 1721.