Type:
Educational Exhibit
Keywords:
Education and training, Diagnostic procedure, MR, CT, Conventional radiography, Thorax, Paediatric, Lung
Authors:
M. PITARCH DIAGO1, C. Martin Martinez1, V. P. Beltrán Salazar1, C. Duran Feliubadaló1, D. Rodriguez Martinez1, B. Del Rio2, F. Bosch Barragan1, A. Gonzalez Lopez1, A. B. A. B. CASTRO GARCIA2; 1Sabadell/ES, 2Terrassa/ES
DOI:
10.1594/ecr2018/C-3056
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 even prominent.
This is compensatory emphysema.
2) The lung with decreased vascularization is highly likely to be the pathological one (Fig. 2).
Causes: congenital (e.g.,
pulmonary artery agenesis),
secondary to obstruction (e.g.,
pulmonary embolism),
or vasospasm.
Vasospasm is caused by decreased lung ventilation.
For example,
in partial airway obstruction,
trapped air causes pulmonary vasoconstriction due to hypercapnia.
This is obstructive emphysema.
3) A small,
completely radiopaque lung in an inspiratory radiograph is always pathological (Fig. 3).
It indicates volume loss and the differential diagnosis must include atelectasis (most commonly),
lung agenesis,
or pneumectomy.
4) A lack of (or minimal) change in lung shape between inspiration and expiration is usually pathological (Fig. 4).
Causes: extrinsic or intrinsic airway obstruction (e.g.,
a foreign body).