ESR Essentials: imaging of common paediatric pulmonary diseases-practice recommendations by the European Society of Paediatric Radiology

Abstract

Chest imaging in children presents unique challenges due to varying requirements across age groups. For chest radiographs, achieving optimal images often involves careful positioning and immobilisation techniques. Antero-posterior projections are easier to obtain in younger children, while lateral decubitus radiographs are sometimes used when expiratory images are difficult to obtain and for free air exclusion. Chest CT protocols should be age-dependent to minimise radiation exposure and motion artefacts. MRI is primarily used in specialised centres to reduce radiation exposure, requiring specific expertise and sedation in younger children. Respiratory distress syndrome is a leading cause of morbidity in preterm neonates, diagnosed through characteristic radiographic findings and a history of prematurity. Bronchopulmonary dysplasia is the most common complication of extreme preterm birth and chronic oxygen therapy; imaging is used for predicting outcomes for the assessment of severe cases. Transient tachypnoea of the newborn and meconium aspiration syndrome are common in term infants, with specific imaging characteristics aiding in their differentiation. Congenital lung malformations present diagnostic and management challenges, with imaging playing a crucial role in diagnosis and surgical planning. Finally, imaging is essential in detecting complications from pneumonia in children, such as empyema and necrotic pneumonia, or in identifying foreign object aspiration. CLINICAL RELEVANCE STATEMENT: This review summarises current radiology practice of paediatric chest pathologies, aiding in the accurate diagnosis and management of neonatal and congenital pulmonary conditions and pneumonia complications, ultimately improving patient outcomes through precise imaging interpretation and targeted clinical intervention. KEY POINTS: Chest radiographs should be systematically assessed for pathology. Ensure accurate differential diagnosis of neonatal lung diseases by collecting information on gestational age, method of delivery, presenting symptoms, ventilation type, and fetal ultrasound findings. Radiographs and ultrasound are initial diagnostic tools for paediatric pulmonary disease; CT should be reserved for complex cases. Referral to paediatric hospital should be considered when the use of chest MRI is indicated.

Keywords: Congenital; Diagnostic imaging; Infant; Lung; Paediatrics.

Fig. 1

Flowchart of differential diagnosis in neonatal pulmonary disease (excluding systemic/extrathoracic manifestations, such as sepsis, severe anaemia and skeletal dysplasia) causing respiratory distress

Fig. 2

Respiratory distress syndrome grading on chest radiographs. A RDS grade 1: a ground-glass appearance of the lungs with well-expanded lung and with limited air bronchogram, (B) RDS grade 2: more prominent opacification of the lung, which is relatively well-expanded, but with increased presence of air bronchogram and still well distinct heart and diaphragmatic contours. C RDS grade 3: coarse granular opacification of the lungs and less distinct cardiac and diaphragmatic silhouette, widespread air bronchograms and poorly expanded lungs and (D) RDS grade 4: total collapse of the lungs with complete opacification, indistinct cardiac and diaphragmatic silhouettes and widespread distinct air bronchograms

Fig. 3

Bronchopulmonary dysplasia (BPD): A Free-breathing CT image of a mild BPD patient and (B) Photon Counting CT image of a severe BPD patient. Typical features of BPD include areas of low attenuation (arrows) observed in both mild and severe BPD cases, linear opacities (thick arrow), and consolidation (arrowhead) in severe BPD patients

Fig. 4

Pathophysiology of meconium aspiration syndrome (MAS): Prolonged hypoxia stimulates fetal breathing and gasping, leading to inhalation of amniotic fluid and increased peristalsis with anal sphincter relaxation. This allows meconium to pass into the amniotic fluid, which can be aspirated during fetal gasping or initial breaths. Aspirated meconium causes airway obstruction, resulting in areas of atelectasis and/or hyperinflation distally. It also triggers inflammatory pneumonitis with epithelial damage and reduces surfactant activity and synthesis, further promoting atelectasis and consolidation. Decreased alveolar ventilation and ventilation-perfusion mismatch lead to hypoxaemia, causing respiratory distress and increasing infection risk. Persistent pulmonary hypertension is an associated complication of MAS

Fig. 5

Mixed lesion comprising congenital pulmonary airway malformation (CPAM) type 2 and Intralobar sequestration (ILS) in a 1-week-old girl. A Antero-posterior (AP) chest radiograph revealing a poorly defined lesion in the right lung base (thin arrow in A). B CT, coronal plane, lung window, highlighting multiple cysts smaller than 2 cm associated with the CPAM type 2 component (thick arrow). C CECT, mediastinal window displaying a soft tissue-enhancing lung lesion in the right lower lobe (arrowhead), supplied by the descending aorta and draining through the pulmonary vein (not shown)

Fig. 6

Comparison of congenital lobar overinflation (CLO) and bronchial atresia (BA) in children. A Chest radiograph, (B) coronal CT lung window image of a 3-year-old girl, and (C) a follow-up CT at 12 years. Notice the left upper lung lucency and asymmetric expansion compared to the right (arrow in A), corresponding to hyperinflated left upper lobe on the CT at the same age (arrowhead in B). By age 12, the patient presents with symptomatic progressive hyperinflation of the left upper lobe (thick arrow in C). D Post contrast CT, coronal plane, mediastinum window and (E) coronal plane, lung window and (F) coronal T2-weighted single-shot fast spin echo MRI in a 7-year-old boy with bronchial atresia in the apical segment of the left lower lobe. Observe the bronchocele with soft tissue density (arrow in D), hyperinflation of the apical segment of the lower lobe displaying lower density (arrowhead in E), and increased T2 signal on MRI indicating mucus within the bronchocele (thick arrow in F)

Fig. 7

Radiographic-CT correlation. Recurrence of congenital diaphragmatic hernia (CDH) (A, D), complicated pneumonia with empyema (B, E), and foreign object aspiration (FOA) (C, F) in a 1-year-old girl, 3-year-old boy, and 2-year-old girl, respectively. A–C Anterior-posterior chest radiograph, (D, E) contrast-enhanced CT (CECT) and (F) coronal minimum intensity projection (MinIP). A and D reveal the surgical patch (black arrows) used for CDH correction, outlining the diaphragmatic contour and herniated bowels loop in the left hemithorax (thick arrows). B demonstrates complete opacification of the left lung (arrow) with loss of diaphragm and heart contours, indicative of the silhouette sign. This finding, confirmed on CECT, reveals a combination of pleural effusion (thick arrow in E) and atelectasis of the left lung (thin arrow in E). C depicts hyperinflation of the left lung (thin arrow), more conspicuous on CT (thin arrow in F) with an obstructing material in the left main bronchus (thick arrow in F). At bronchoscopy, a toy plastic piece and mucus plugs were extracted

Fig. 8

Clinical progression of round pneumonia in an 11-year-old boy. A Chest radiograph (CR) on admission revealing a round opacity (arrow) within the right hemithorax. B Lung ultrasound (LUS) shows oval-shaped subpleural consolidation with mild central increase in echogenicity (white arrows) related to the pre-necrotic stage of round pneumonia. C Two days later, LUS revealing distinct small hypoechogenic zones of necrosis (thick arrow). D Reaeration starting at the periphery of consolidation (thin black arrows), with persistent central necrosis observed after 3 days. E One week later, lung consolidation significantly reduced in size with diffuse reaeration and absence of detectable necrotic zones. F Follow-up CR confirming significant regression of pneumonia