Diagnostic ultrasound ( PDFDrive )

CHAPTER
50
The Pediatric Chest
Chetan Chandulal Shah and S. Bruce Greenberg
SUMMARY OF KEY POINTS
• Ultrasound of the chest plays an important role in
diagnosis and treatment of pleural effusion and empyema.
• Real-time ultrasound is very useful in evaluation of
diaphragmatic motion disorders.
• Ultrasound can determine if a neoplastic lesion is solid or
cystic.
• Doppler and color ultrasound can evaluate vascularity of a
lesion and vascular thrombosis.
• Ultrasound of the chest is very useful in differentiating
among (1) solid mass and large or persistent pleural
effusion when there is a totally or partially opaque
hemithorax on chest radiographs; (2) round pneumonia and
mediastinal mass; and (3) normal thymus and mediastinal
mass.
• Ultrasound guidance is helpful for interventional chest
procedures.
CHAPTER OUTLINE
ULTRASOUND TECHNIQUE
PLEURAL EFFUSION AND EMPYEMA
Sonographic Signs of Pleural Fluid
Free Fluid Movement With
Respiration
Fluid Color Flow Doppler Signal
Diaphragm Sign
Displaced-Crus Sign
Bare-Area Sign
Sonography Versus Computed
Tomography Scan
Mass Versus Fluid
Parapneumonic Collections and
Empyema
Lung Abscess Versus Empyema
LUNG PARENCHYMAL DISORDERS
Pneumonia
Round Pneumonia
Chest Radiograph or Ultrasound?
Atelectasis
Congenital Pulmonary Airway
Malformation
Bronchopulmonary Foregut
Malformation
DIAPHRAGM DISORDERS
VASCULAR DISORDERS
Vascular Thrombosis
Lymphovascular Malformation
MEDIASTINAL MASSES
Thymic Index
Abnormal Location of Thymus
Mimicking Mass Lesion
Anterior Mediastinal Masses
Lymphadenopathy
Posterior Mediastinal Masses
ULTRASOUND-GUIDED
INTERVENTIONAL PROCEDURES
OTHER LESS ESTABLISHED
INDICATIONS
Extracardiac chest sonography is limited by air in the lungs
and bone in the thoracic cage. However, ultrasound is valuable
for evaluating the abnormal chest in which luid and solid
structures interpose between the chest wall and lung. Sonography
is particularly well suited for the evaluation of pleural efusion
and empyema. he thymus, liver, and spleen provide windows
for chest sonography. Any radiographically opaque chest can be
further evaluated by sonography to determine whether there is
pleural luid, a chest mass, atelectasis, consolidation, or lung
hypoplasia. Ultrasound may show the pulmonary mass reaching
the periphery but may not be able to provide a speciic diagnosis.
Computed tomography (CT) is required for evaluation of the
extent of the mass. Biopsy might be required to arrive at a speciic
diagnosis.
Ultrasound can be used to guide thoracentesis, chest tube
placement, or biopsy of the pleura, the lung, or a mediastinal
mass. he indications for extracardiac chest sonography are listed
in the accompanying box. Breast, cardiac, and pericardial lesions
are beyond the scope of this chapter.
ULTRASOUND TECHNIQUE
Linear transducers with frequencies ranging from 5 to
15 MHz are used for chest ultrasound. 1 Diaphragmatic
motion can best be assessed using real-time ultrasound
comparison of the diaphragmatic motion on the right and the
let sides. Color low Doppler sonographic imaging is useful
to demonstrate vascular supply, which is important in the
diagnosis of sequestration. he selection of the frequency of
the transducer is inversely dependent on patient size. Higher
frequencies are used for infants, and lower frequencies for
adolescents. 2
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