Learning objectives
To review the key signs in the evaluation of pulmonary asymmetry.
To review pediatric diseases that present with a unilateral hyperlucent hemithorax.
To highlight the role of fetal MRI in prenatal diagnosis.
Background
Asymmetric lung aeration is not uncommon in pediatrics.
It is important to take into account factors related to image acquisition,
such as the patient’s position.
There will normally be other details that allow asymmetry to be attributed to technical factors.
Some key signs make it possible to identify the pathologic hemithorax:
1)The lung with normal vascularization is NOT the pathological one (Fig. 1).
For example,
in pulmonary hypoplasia,
the contralateral lung is larger and hyperlucent (due to compensatory hyperexpansion) and the vessels are normal or...
Findings and procedure details
We use a literature review and images from our case series to describe and illustrate the different conditions that can present with unilateral hyperlucent hemithorax in pediatric patients.
Causes of pulmonary asymmetry in children can be classified in 5 categories according to whether the abnormality lies in the lung parenchyma,
pleural space,
chest wall,
lung vascularization,
or airway (Table 1).
A. Abnormalities in the lung parenchyma:
Congenital lobar emphysema (Fig. 5): typically presents with a large,
hyperlucent hemithorax.
It can affect any lobe,
though the...
Conclusion
When pulmonary asymmetry is seen on chest radiographs,
aspects such as pulmonary vascularization or changes in the inspiration-expiration sequence are essential for determining which lung is pathologic. To ensure correct therapeutic management in each case,
radiologists need to know the different causes of a unilateral hyperlucent hemithorax.
Fetal MRI plays an important role in the prenatal diagnosis of some congenital lung diseases.
References
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