Developmental lung malformations in children: recent advances in imaging techniques, classification system, and imaging findings

Surgical repair of an obstructed mixed-type total anomalous pulmonary venous connection

Total anomalous pulmonary venous connection is a rare congenital anomaly and has four anatomical subtypes of which the mixed type represents diagnostic and therapeutic challenge. When associated with obstruction, however, urgent surgical repair is needed. Herein, we present a rare case of obstructed mixed type total anomalous pulmonary venous connection with successful surgical repair.

Magnetic resonance imaging for congenital lung malformations

Congenital lung malformations are most often identified on prenatal US screening. Fetal MRI is often performed to further evaluate these lesions. Although some of these lesions might cause prenatal or early postnatal symptoms that require urgent management, the majority are asymptomatic at birth and might be subtle or invisible on chest radiographs. Postnatal imaging is frequently deferred until 3-6 months of age, when surgery or long-term conservative management is contemplated. High-quality imaging and interpretation is needed to assist with appropriate decision-making. Contrast-enhanced chest CT, typically with angiographic technique, has been the usual postnatal imaging choice. In this review, the author discusses and illustrates the indications and use of postnatal MR imaging for bronchopulmonary malformations as well as some differential diagnoses and the advantages and disadvantages of MR versus CT.

Thoracic CTA in infants and young children: Image quality of dual-source CT (DSCT) with high-pitch spiral scan mode (turbo flash spiral mode) with or without general anesthesia with free-breathing technique

PURPOSE

To determine whether diagnostic quality thoracic computed tomography angiography (CTA) studies can be obtained without general anesthesia (GA) in infants and young children using dual-source computed tomography (DSCT) with turbo flash spiral mode (TFSM) and free-breathing technique.

MATERIALS AND METHODS

All consecutive infants and young children (≤ 6 years old) who underwent thoracic CTA studies from January 2018 to October 2020 for suspected congenital thoracic disorders were categorized into two groups: with GA (Group 1) and without GA (Group 2). All thoracic CTA studies were performed on a DSCT scanner using TFSM and free-breathing technique. Two pediatric thoracic radiologists independently evaluated motion artifact in three lung zones (upper, mid, and lower). Degree of motion artifact was graded 0-3 (0, none; 1, mild; 2, moderate; and 3, severe). Logistic models adjusted for age and gender were used to compare the degree of motion artifact between lung zones. Interobserver agreement between reviewers was evaluated with kappa statistics.

RESULTS

There were a total of 73 pediatric patients (43 males (59%) and 30 females (41%); mean age, 1.4 years; range, 0-5.9 years). Among these 73 patients, 42 patients (58%) underwent thoracic CTA studies with GA (Group 1) and the remaining 31 patients (42%) underwent thoracic CTA studies without GA (Group 2). Overall, the degree of motion artifact was higher for Group 2 (without GA). However, only a very small minority (1/31, 3%) of Group 2 (without GA) thoracic CTA studies had severe motion artifact. There was no significant difference between the two groups with respect to the presence of severe motion artifact (odds ratio [OR] = 6, p = .222). When two groups were compared with respect to the presence of motion artifact for individual lung zones, motion artifact was significantly higher in the upper lung zone for Group 2 (without GA) (OR = 20, p = .043). Interobserver agreement for motion artifact was high, the average Kappa being 0.81 for Group 1 and 0.95 for Group 2.

CONCLUSION

Although the degree of motion artifact was higher in the group without GA, only a small minority (3%) of thoracic CTA studies performed without GA had severe motion artifact, rendering the study nondiagnostic. Therefore, the results of this study support the use of thoracic CTA without GA using DSCT with TFSM and free-breathing in infants and young children. In addition, given that motion artifact was significantly higher in the upper lung zone without GA, increased stabilization in the upper chest and extremities should be considered.

Structural and perfusion magnetic resonance imaging of congenital lung malformations

BACKGROUND

A radiation-free advanced imaging modality is desirable for investigating congenital thoracic malformations in young children.

OBJECTIVE

To describe magnetic resonance imaging (MRI) findings of congenital bronchopulmonary foregut malformations and investigate the ability of lung MRI for their classification.

MATERIALS AND METHODS

This is a retrospective analysis of consecutive MRI examinations performed for suspected congenital lung anomalies in 39 children (median age: 3.8 months, range: 2 days-15 years). Morphological and perfusion findings were characterised on respiratory-gated fast spin echo and dynamic contrast-enhanced sequences obtained at 1.5 tesla. Abnormalities were classified independently by two readers and compared to an expert diagnosis based on pathology, surgery and/or other imaging.

RESULTS

Main diagnoses included bronchopulmonary lesions in 33 patients, scimitar syndrome in 4 patients, pulmonary arteriovenous malformation and oesophageal duplication cyst in one patient each. Of 46 observed abnormalities, 44 (96%) were classified correctly with very good interobserver agreement (96% concordance rate). The 39 detected lung lesions included isolated overinflation (17/39, 44%), cystic pulmonary airway malformation (8/39, 21%), bronchopulmonary sequestration (7/39, 18%), bronchogenic cyst (4/39, 10%) and hybrid lesion (3/39, 8%). All lung lesions presented as perfusion defect at peak pulmonary enhancement. Non-cystic lesions showed a delayed peak (median delay: 2.8 s, interquartile range: 0.5 to 4.0 s) in relation to normal lung parenchyma.

CONCLUSION

A dedicated lung MRI protocol including respiratory compensated sequences, dynamic angiography and perfusion is able to reliably delineate parenchymal and vascular components of congenital bronchopulmonary foregut malformations. Therefore, MRI may be considered for comprehensive postnatal evaluation of congenital thoracic malformations.

Highlights on MRI of the fetal body

Fetal MRI is a level III diagnostic tool performed subsequently a level II prenatal ultrasound (US), in cases of inconclusive ultrasonographic diagnosis or when a further investigation is required to confirm or improve the diagnosis, to plan an appropriate pregnancy management. Fetal MRI plays an increasingly important role in the prenatal diagnosis of fetal neck, chest and abdominal malformations, even if its role has been amply demonstrated, especially, in the field of fetal CNS anomalies. Due to its multiparametricity and multiplanarity, MRI provides a detailed evaluation of the whole fetal respiratory, gastrointestinal and genitourinary systems, especially on T2-weighted (W) images, with a good tissue contrast resolution. In the evaluation of the digestive tract, T1-W sequences are very important in relation to the typical hyperintensity of the large intestine, due to the presence of meconium. The objective of this review is to focus on the application of fetal MRI in neck, chest and abdominal diseases.

Total Anomalous Pulmonary Venous Connection: Preoperative Anatomy, Physiology, Imaging, and Interventional Management of Postoperative Pulmonary Venous Obstruction

Total anomalous pulmonary venous connection refers to a spectrum of cardiac anomalies where the pulmonary veins fail to return to the left atrium and the pulmonary venous blood returns through a systemic vein or directly to the right atrium. There is a wide anatomical variety of venous connections and degrees of pulmonary venous obstruction that affect the presentation, surgical repair, and outcomes. In this review, we explore the preoperative physiology, echocardiographic diagnosis, and approach to postoperative complications.

Perinatal Thoracic Mass Lesions: Pre- and Postnatal Imaging

Chest masses present a common problem in the perinatal period. Advances in prenatal ultrasound, supplemented by fetal magnetic resonance imaging, now allow early detection and detailed characterization of many thoracic lesions in utero. As such, in asymptomatic infants, assessment with postnatal computed tomography or magnetic resonance imaging can often be delayed for several months until the time at which surgery is being contemplated. Bronchopulmonary malformations comprise most of the thoracic masses encountered in clinical practice. However, a variety of other pathologies can mimic their appearances or produce similar effects such as hypoplasia of a lung or both lungs. Understanding of the key differentiating clinical and imaging features can assist in optimizing prognostication and timely management.