Current imaging of prenatally diagnosed congenital lung lesions

Predictive Role of Venous Drainage and Lesion Margins in Bronchopulmonary Sequestration Classification

Background: Bronchopulmonary sequestration (BPS) is a portion of dysplastic pulmonary tissue not communicating with the tracheobronchial tree. Its vascularization is provided by abnormal arteries originating from the systemic circulation. Previous papers report different venous drainage (VD) between intralobar (ILS) and extralobar sequestration (ELS), respectively, into the pulmonary or the systemic veins. The aim of our study is to investigate the VD as independent predictor of the type of PS. Methods: We retrospectively reviewed 41 pediatric patients who underwent surgery for BPS between 2016 and 2023 in two centers. Patients treated prenatally and without pre-operative CT were excluded. BPS were classified either intra or extra lobar. Pre-operative radiological BPS classification prediction was assessed based on intra-operative thoracoscopic findings. Lesion VD and sharp margins (SM) on pre-operative CT were assessed as predicting factors. Results: A total of 36 patients were included: 24 ILS and 12 ELS. All patients underwent thoracoscopic resection without major complications. VD is significantly different between ILS and ELS: 96% of ILS drain into the pulmonary system while 83% of ELS drain into a systemic vein (p < 0.00001). On pre-operative CT, the absence of SM predicts for an ILS in 100% of cases. SM has a PPV for ELS of 85.7%. The combination of SM and systemic VD has a PPV for ELS of 91.7%. Conclusions: In our series, the absence of SM alone is suggestive for an ILS in 100% of cases, while the combination of SM and systemic VD is more accurate in predicting ELS. This may help improving surgical planning and family consultation.

Association of Prenatal Congenital Lung Malformation Volume Ratio to Postnatal Computed Tomography Characteristics

INTRODUCTION

Congenital lung malformations (CLMs) are diverse and readily diagnosed on prenatal ultrasound. Postnatal computed tomography (CT) characteristics, including volume, are used in centers for the clinical decision-making of asymptomatic CLM. We aim to evaluate the relationship of prenatal CLM volume ratio (CVR) to postnatal CT characteristics by suspected prenatal diagnosis and postnatal radiological diagnosis.

METHODS

We performed a single-center retrospective review of all patients evaluated with prenatally diagnosed CLM (May 2015-December 2022). Demographics, prenatal imaging findings at initial evaluation, and postnatal radiological diagnosis/imaging findings were analyzed with descriptive statistics. Pairwise correlation coefficient tests were performed to analyze the correlation between prenatal CVR and postnatal CT lesion size stratified by diagnosis.

RESULTS

Of 123 patients referred and evaluated, suspected prenatal diagnoses consisted of 68 bronchial atresia (BA), 20 intralobar bronchopulmonary sequestration (iBPS), 20 extralobar bronchopulmonary sequestration (eBPS), and nine congenital pulmonary airway malformation (CPAM). Postnatal radiological diagnoses consisted of 53 BA, 22 iBPS, 14 eBPS, and 20 CPAM. Overall correlation coefficient of prenatal CVR to postnatal CT lesion size volume was 0.56. By suspected prenatal diagnosis, correlation coefficients were 0.61 (BA), 0.59 (iBPS), 0.29 (eBPS), and 0.51 (CPAM). For postnatal radiological diagnosis, correlation coefficients were 0.58 (BA), 0.56 (iBPS), 0.33 (eBPS), and 0.62 (CPAM).

CONCLUSIONS

Our results indicate that initial CVR is overall consistent with the postnatal CT lesion size. This correlation is present in suspected prenatal diagnoses of BA and iBPS and postnatal radiological diagnoses of BA, iBPS, and CPAM. Additional studies analyzing long-term follow-up should be conducted to specify the safety of patients who undergo observation rather than surgical intervention.

Fetal imaging of congenital lung lesions with postnatal correlation

Congenital lung lesions are a rare group of developmental pulmonary abnormalities that are often first identified prenatally on routine second-trimester US. Congenital pulmonary airway malformation (CPAM) is the most common anomaly while others include bronchopulmonary sequestration, congenital lobar overinflation, bronchogenic cyst and bronchial atresia. Clinical presentation is highly variable, ranging from apparent in utero resolution to severe mass effect with resultant hydrops fetalis and fetal demise. Differentiation among these lesions can be challenging because overlapping imaging features are often present. The roles of the radiologist are to identify key imaging findings that help in diagnosing congenital lung lesions and to recognize any ominous features that might require prenatal or perinatal intervention. High-resolution US and complementary rapid-acquisition fetal MRI provide valuable information necessary for lesion characterization. Postnatal US and CT angiography are helpful for lesion evaluation and for possible surgical planning. This article reviews the embryology of the lungs, the normal prenatal imaging appearance of the thorax and its contents, and the prenatal and neonatal imaging characteristics, prognosis and management of various congenital lung lesions.

A single institution's experience with the management of peripheral bronchial atresia

PURPOSE

Peripheral bronchial atresia is a pulmonary abnormality diagnosed on postnatal computed tomography after prenatal imaging reveals a congenital lung lesion. Debate regarding management of this abnormality prompted us to review our institution's practice patterns and outcomes.

METHODS

All patients diagnosed with bronchial atresia were assessed from 6/2014 to 7/2020. Pediatric radiologists were surveyed to delineate computed tomography criteria used to diagnose peripheral bronchial atresia. Criteria were applied in an independent blinded review of postnatal imaging. Data for patients determined to have peripheral bronchial atresia and at least an initial pediatric surgical evaluation were analyzed.

RESULTS

Twenty-eight patients with bronchial atresia received at least an initial pediatric surgical evaluation. Expectant management was planned for 22/28 (79%) patients. Two patients transitioned from an expectant management strategy to an operative strategy for recurrent respiratory infections; final pathology revealed bronchial atresia in both. Six patients were initially managed operatively; final pathology revealed bronchial atresia (n = 3) or congenital lobar overinflation (n = 3).

CONCLUSIONS

Peripheral bronchial atresia can be safely managed expectantly. A change in symptoms is suspicious for alternate lung pathology, warranting further workup and consideration for resection.

LEVEL OF EVIDENCE

Level IV.

Congenital lung lesions: a radiographic pattern approach

Congenital lung malformations represent a spectrum of abnormalities that can overlap in imaging appearance and frequently coexist in the same child. Imaging diagnosis in the neonatal period can be challenging; however, the recognition of several archetypal radiographic patterns can aid in narrowing the differential diagnosis. Major radiographic archetypes include (1) hyperlucent lung, (2) pulmonary cysts, (3) focal opacity and (4) normal radiograph. Here we review the multimodality imaging appearances of the most commonly seen congenital lung malformations, categorized by their primary imaging archetypes. Along with the congenital lung malformations, we present several important imaging mimickers.

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.

Pediatric Congenital Lung Malformations: Imaging Guidelines and Recommendations

Congenital lung malformations are a spectrum of developmental anomalies comprised of malformations of the lung parenchyma, airways, and vasculature. Imaging assessment plays a pivotal role in the initial diagnosis, management, and follow-up evaluation of congenital lung malformations in the pediatric population. However, there is currently a lack of practical imaging guidelines and recommendations for the diagnostic imaging assessment of congenital lung malformations in infants and children. This article reviews the current evidence regarding the imaging evaluation of congenital lung malformations and provides up-to-date imaging recommendations for pediatric congenital lung malformations.

Characterization of the Hyperintense Bronchus Sign as a Fetal MRI Marker of Airway Obstruction

Background Fetal MRI-based differential diagnosis of congenital lung malformations is difficult because of the paucity of well-described imaging markers. Purpose To characterize the hyperintense bronchus sign (HBS) in in vivo fetal MRI of congenital lung malformation cases. Materials and Methods In this retrospective two-center study, fetal MRI scans obtained in fetuses with congenital lung malformations at US (January 2002 to September 2018) were reviewed for the HBS, a tubular or branching hyperintense structure within a lung lesion on T2-weighted images. The frequency of the HBS and respective gestational ages in weeks and days were analyzed. Areas under the curve (AUCs), 95% CIs, and P values of the HBS regarding airway obstruction, as found in histopathologic and postnatal CT findings as the reference standards, were calculated for different gestational ages. Results A total of 177 fetuses with congenital lung malformations (95 male fetuses) and 248 fetal MRI scans obtained at a median gestational age of 25.6 weeks (interquartile range, 8.9 weeks) were included. The HBS was found in 79% (53 of 67) of fetuses with bronchial atresia, 71% (39 of 55) with bronchopulmonary sequestration (BPS), 43% (three of seven) with hybrid lesion, 15% (six of 40) with congenital cystic adenomatoid malformation, and 13% (one of eight) with bronchogenic cyst at a median gestational age of 24.9 weeks (interquartile range, 9.7 weeks). HBS on MRI scans at any gestational age had an AUC of 0.76 (95% CI: 0.70, 0.83; P = .04) for the presence of isolated or BPS-associated airway obstruction at histopathologic analysis and postnatal CT. The AUC of HBS on fetal MRI scans obtained until gestational age of 26 weeks (AUC, 0.83; 95% CI: 0.75, 0.91; P < .001) was significantly higher (P = .045) than that for fetal MRI scans obtained after gestational age 26 weeks (AUC, 0.69; 95% CI: 0.57, 0.80; P = .004). Conclusion The hyperintense bronchus sign is a frequently detectable feature at fetal MRI and is associated with airway obstruction particularly before gestational age 26 weeks. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Dubinsky in this issue.

A clinical guideline for structured assessment of CT-imaging in congenital lung abnormalities

OBJECTIVES

To develop a clinical guideline for structured assessment and uniform reporting of congenital lung abnormalities (CLA) on Computed Tomography (CT)-scans.

MATERIALS AND METHODS

A systematic literature search was conducted for articles describing CT-scan abnormalities of congenital pulmonary airway malformation (CPAM), bronchopulmonary sequestration (BPS), congenital lobar emphysema (CLE) and bronchogenic cyst (BC). A structured report using objective features of CLA was developed after consensus between a pediatric pulmonologist, radiologist and surgeon.

RESULTS

Of 1581 articles identified, 158 remained after title-abstract screening by two independent reviewers. After assessing full-texts, we included 28 retrospective cohort-studies. Air-containing cysts and soft tissue masses are described in both CPAM and BPS while anomalous arterial blood supply is only found in BPS. Perilesional low-attenuation areas, atelectasis and mediastinal shift may be found in all aforementioned abnormalities and can also be seen in CLE as a cause of a hyperinflated lobe. We have developed a structured report, subdivided into five sections: Location & Extent, Airway, Lesion, Vascularization and Surrounding tissue.

CONCLUSIONS

CT-imaging findings in CLA are broad and nomenclature is variable. Overlap is seen between and within abnormalities, possibly due to definitions often being based on pathological findings, which is an unsuitable approach for CT imaging. We propose a structured assessment of CLA using objective radiological features and uniform nomenclature to improve reporting.

Fetal ultrasound and magnetic resonance imaging: a primer on how to interpret prenatal lung lesions

Fetal lung lesions include common lesions such as congenital pulmonary airway malformation (CPAM), bronchopulmonary sequestration (BPS) and combined CPAM-BPS hybrid lesions, as well as less common entities including congenital lobar emphysema/obstruction, bronchial atresia, bronchogenic cysts and rare malignant pulmonary lesions such as pleuropulmonary blastoma. Fetal lung lesions occur in approximately 1 in 15,000 live births and are thought to arise from a spectrum of abnormalities related to airway obstruction and malformation, with the lesion type depending on the timing of insult, level of bronchial tree involvement, and severity of obstruction. Lesions vary from small and asymptomatic to large and symptomatic with significant mass effect on surrounding structures. Accurate diagnosis and characterization of these anomalies is crucial for guiding patient counseling as well as perinatal and postnatal management. The goal of this review is to provide an overview of normal fetal lung appearance and imaging features of common and uncommon lesions on both ultrasound and MR imaging, and to discuss key aspects in reporting and evaluating the severity of these lesions.

A retrospective clinical analysis of 20 cases of congenital lung masses

BACKGROUND

Congenital-pulmonary-airway-malformation (CPAM) and bronchopulmonary-sequestration (BPS) are rare conditions. The objective of this study was to describe the sonographic characteristics and prenatal course of fetal lung mass.

METHODS

A retrospective study on 20 pregnancies with CPAM and BPS diagnosed during 2018-2018 was performed. Data evaluated included gestational age (GA) at diagnosis, size of lesion, CPAM-volume-ratio (CVR), associated sonographic findings and pregnancy outcome.

RESULTS

Fourteen cases of CPAM and six cases of BPS were evaluated. The average GA at diagnosis was 22 weeks'-gestation (range 17-26). 66% were macrocystic-multicystic. Five cases of BPS (71.4%) had other structural anomalies. None of the fetuses with CPAM had additional anomalies. Four pregnancies (20%) underwent termination due to severe hydrops fetalis. Two cases of CPAM (15%) had spontaneous resolution by 30 week's-gestation; three cases (20%) continued to grow during pregnancy and all the rest reached their largest size at 25-28 week's-gestation. Most cases delivered at term (average 37.6 range 32.2-41.4). Two children had lobectomy at 11 and 12 months of life.

CONCLUSIONS

Careful follow-up during pregnancy may result in term delivery of adequate-for-gestational-age newborns, with no need for admission to the NICU, with only 10% need for lobectomy during the first year of life.

Thoracoscopic Resection of Congenital Lung Malformation: Looking for the Right Preoperative Assessment

INTRODUCTION

 Consensus on the best postnatal radiological evaluation of congenital lung malformations (CLMs) is still lacking. In recent years, the interest on magnetic resonance imaging (MRI) has grown, but its role is still unknown.

AIM

 The aim of the study was to identify the best preoperative diagnostic assessment for CLM.

MATERIALS AND METHODS

 All patients with a prenatal suspicion of CLM between January 2014 and February 2018 were studied. Asymptomatic newborns underwent MRI, during spontaneous sleep without contrast. Patients with a positive MRI were scheduled for computed tomography (CT) within the fourth month of life. Thoracoscopic resection was performed in cases with a pathological CT. MRI, CT, and surgical findings were compared based on dimension, localization, and features of the CLM using the Cohen's kappa test (K).

RESULTS

 A total of 20 patients were included (10 males). No difference was found in the diameter and site of the lesions always localized in the same side (K = 1) and in the same pulmonary lobe (K = 1). Infants who underwent thoracoscopic resection included: three congenital pulmonary airway malformations (CPAMs), five extralobar and eight intralobar sequestrations (bronchopulmonary sequestrations [BPSs]), three bronchogenic cysts, and one congenital emphysema. The concordance between MRI and CT and between radiological investigations and pathology was satisfactory for the greatest part of the studied variables. MRI showed sensitivity of 100%, specificity of 82%, positive predictive value of 50% and negative predictive value of 100% for CPAM and 77, 100, 100, and 80% for BPS, respectively.

CONCLUSION

 MRI proved to be a reliable diagnostic investigation for CLM with high sensitivity and specificity. Early MRI in spontaneous sleep without contrast and preoperative contrast CT scan is a valuable preoperatory assessment.

Optimization of Pediatric Body CT Angiography: What Radiologists Need to Know

OBJECTIVE. Pediatric CT angiography (CTA) presents unique challenges compared with adult CTA. Because of the ionizing radiation exposure, CTA should be used judiciously in children. The pearls offered here are observations gleaned from the authors' experience in the use of pediatric CTA. We also present some potential follies to be avoided. CONCLUSION. Understanding the underlying principles and paying meticulous attention to detail can substantially optimize dose and improve the diagnostic quality of pediatric CTA.

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.

Agreement between magnetic resonance imaging and computed tomography in the postnatal evaluation of congenital lung malformations: a pilot study

OBJECTIVES

To compare postnatal magnetic resonance imaging (MRI) with the reference standard computed tomography (CT) in the identification of the key features for diagnosing different types of congenital lung malformation (CLM).

METHODS

Respiratory-triggered T2-weighted single-shot turbo spin echo (ss-TSE), respiratory-triggered T1-weighted turbo field echo (TFE), balanced fast field echo (BFFE), and T2-weighted MultiVane sequences were performed at 1.5 T on 20 patients prospectively enrolled. Two independent radiologists examined the postnatal CT and MRI evaluating the presence of cysts, hyperinflation, solid component, abnormal arteries and/or venous drainage, and bronchocele. Diagnostic performance of MRI was calculated and the agreement between the findings was assessed using the McNemar-Bowker test. Interobserver agreement was measured with the kappa coefficient.

RESULTS

CT reported five congenital pulmonary airway malformations (CPAMs), eight segmental bronchial atresias, five bronchopulmonary sequestrations (BPS), one congenital lobar overinflation, one bronchogenic cyst, and three hybrid lesions. MRI reported the correct diagnosis in 19/20 (95%) patients and the malformation was correctly classified in 22/23 cases (96%). MRI correctly identified all the key findings described on the CT except for the abnormal vascularization (85.7% sensitivity, 100% specificity, 100% PPV, 94.1% NPV, 95% accuracy for arterial vessels; 57.1% sensitivity, 100% specificity, 100% PPV, 84.2% NPV, 87% accuracy for venous drainage).

CONCLUSIONS

MRI can represent an effective alternative to CT in the postnatal assessment of CLM. In order to further narrow the gap with CT, the use of contrast material and improvements in sequence design are needed to obtain detailed information on vascularization, which is essential for surgical planning.

KEY POINTS

• Congenital lung malformations (CLMs) can be effectively studied by MRI avoiding radiation exposure. • Crucial features of CLM have similar appearance when comparing CT with MRI. • MRI performs very well in CLM except for aberrant vessel detection and characterization.

Fetal Congenital Peripheral Bronchial Atresia Diagnosed by Magnetic Resonance Imaging: Two Case Reports

Two types of congenital bronchial atresia (proximal and peripheral) have been classified. We report two cases of peripheral bronchial atresia diagnosed by prenatal ultrasonography (US) and magnetic resonance imaging (MRI). Evaluating an enlarged lung mass that is homogeneously hyperechoic on US and hyperintense on T2-weighted MRI can help in determining whether bronchial atresia is present. Proximal type is suggested when a dilated main bronchus is observed as a tubule structure of an involved lung hilum. In our cases, T2-weighted MRI revealed homogeneously hyperintense lung lesion with decreased signal intensity of adjacent lobe, flattening diaphragm, and mediastinal shift. Dilatation of the main bronchus was not observed and the opposite lung was normal in appearance. These findings were explained by secondary compression due to enlargement of the involved lung. The preservation of vascular structure and the retained normal shape, though enlarged, in the affected lobe were observed, which demonstrated undisrupted pulmonary architecture of the lobe. Thus, congenital cystic adenomatoid malformation was excluded because pulmonary architecture was relatively preserved. Finally, presumed diagnoses of the peripheral bronchial atresia were made and confirmed by postnatal chest computed tomography.

Prenatal diagnosis of congenital lobar fluid overload

Prenatal congenital lobar fluid overload (CLFO), which was first described by Ramsay and Byron, is identical to postnatal congenital lobar overinflation. It is characterized by progressive lobar overexpansion that compresses the other adjacent lung lobes. The underlying cause can be an intrinsic cartilaginous abnormality or an extrinsic airway compression. It may be associated with cardiovascular anomalies in 12%-14% of cases and affects males more frequently than females. Most cases are diagnosed postnatally, but early antenatal diagnosis and sequential follow-up are attempted for early treatment, if clinically indicated. This article provided a thorough review of CLFO, including prenatal diagnosis and differential diagnoses, as well as comprehensive illustrations of the perinatal imaging findings of CLFO. Prenatal diagnosis of fetal lung lesions should include CLFO in the differential diagnosis and prompt investigation for associated anomalies.

Usefulness of fetal magnetic resonance imaging for postnatal management of congenital lung cysts: prediction of probability for emergency surgery

BACKGROUND

Emergency rescue lung resection is rarely performed to treat congenital lung cysts (CLCs) in neonates. Many reports have described fetal CLC treatment; however, prenatal predictors for postnatal respiratory failure have not been characterized. We hypothesized that fetal imaging findings are useful predictors of emergency surgery.

METHODS

We retrospectively studied patients with CLC who underwent lung surgery during the neonatal period in our hospital between January 2001 and December 2015. The demographic data, fetal imaging findings, and intra- and postoperative courses of patients who underwent emergency surgery (Em group) were compared with those of patients who received elective surgery, i.e., non-emergency surgery (Ne group).

RESULTS

The Em group and Ne group included 7 and 11 patients, respectively. No significant difference was noted in gestational age, time at prenatal diagnosis, birth weight, and body weight at surgery. The volumes of contralateral lung per thoracic volume were significantly smaller in the Em group than in the Ne group (p = 0.0188). Mediastinal compression was more common in the Em group (7/7) than in the Ne group (4/11) (p = 0.0128).

CONCLUSIONS

This is the report describing neonatal emergency lobectomy in patients with CLC evaluated by fetal MRI using the lung volume ratio and mediastinal shift. In patients with CLC, mediastinal shift and significant decreases in contralateral lung volumes during the fetal stages are good prenatal predictors of postnatal emergency lung resection.

Neonatal Lung Disorders: Pattern Recognition Approach to Diagnosis

OBJECTIVE

Lung disease is a common indication for neonates to require medical attention, and neonatal chest radiographs are among the most common studies interpreted by pediatric radiologists. Radiographic features of many neonatal lung disorders overlap, and it may be difficult to differentiate among conditions.

CONCLUSION

This review presents an up-to-date practical approach to the radiologic diagnosis of neonatal lung disorders, with a focus on pattern recognition and consideration of clinical history, patient age, and symptoms.

The natural history of prenatally diagnosed congenital cystic lung lesions: long-term follow-up of 119 cases

BACKGROUND

A paucity of evidence regarding the natural history of congenital pulmonary airway malformations (CPAMs) and pulmonary sequestration (PS) has resulted in a divergence in management strategy of asymptomatic cases.

METHODS

We describe the long-term clinical course of 119 children diagnosed with these lesions treated at Great Ormond Street Hospital (GOSH). Cases were identified via the GOSH patient database. Study entry required the identification of a cystic lung lesion on prenatal ultrasound and confirmation of CPAM/PS on postnatal CT imaging. Patients followed up for at least 5 years were included.

RESULTS

51 (43%) patients were managed surgically; 8 (6.7%) as an emergency during the neonatal period, 6 (5.1%) electively due to concerning features on CT scan, 20 (17%) following medical advice, 1 (0.8%) following a severe respiratory infection and in 5 (4.2%) the indication was unclear. The indication in 11 (9.2%) was recurrent respiratory infection and median age at surgery was 1.6 years (range 0.4 to 4.6 years). No cases of malignancy were identified on histological examination of resected lesions. 68 (57%) patients were managed conservatively for a median period of 9.9 years (range 5.2 years to 18 years). Seven (10%) were discharged, one was followed-up elsewhere (1.5%) and eight (11%) were lost to follow-up. In four patients (5.9%), the lesion resolved spontaneously. 52 (76%) continue to be followed-up and remain asymptomatic.

CONCLUSIONS

This is one of the largest case series documenting the natural history of CPAMs and PS following a prenatal diagnosis and demonstrates that conservative management is a reasonable option in selected cases.

Treatment of congenital pulmonary airway malformations: a systematic review from the APSA outcomes and evidence based practice committee

PURPOSE

Variation in management characterizes treatment of infants with a congenital pulmonary airway malformation (CPAM). This review addresses six clinically applicable questions using available evidence to provide recommendations for the treatment of these patients.

METHODS

Questions regarding the management of a pediatric patient with a CPAM were generated. English language articles published between 1960 and 2014 were compiled after searching Medline and OvidSP. The articles were divided by subject area and by the question asked, then reviewed and included if they specifically addressed the proposed question.

RESULTS

1040 articles were identified on initial search. After screening abstracts per eligibility criteria, 130 articles were used to answer the proposed questions. Based on the available literature, resection of an asymptomatic CPAM is controversial, and when performed is usually completed within the first six months of life. Lobectomy remains the standard resection method for CPAM, and can be performed thoracoscopically or via thoracotomy. There is no consensus regarding a monitoring protocol for observing asymptomatic lesions, although at least one chest computerized tomogram (CT) should be performed postnatally for lesion characterization. An antenatally identified CPAM can be evaluated with MRI if fetal intervention is being considered, but is not required for the fetus with a lesion not at risk for hydrops. Prenatal consultation should be offered for infants with CPAM and encouraged for those infants in whom characteristics indicate risk of hydrops.

CONCLUSIONS

Very few articles provided definitive recommendations for care of the patient with a CPAM and none reported Level I or II evidence. Based on available information, CPAMs are usually resected early in life if at all. A prenatally diagnosed congenital lung lesion should be evaluated postnatally with CT, and prenatal counseling should be undertaken in patients at risk for hydrops.

Postnatal Evaluation of Congenital Chest Pathologies Using a Low-Dose Computed Tomography (CT) Protocol - a Pictorial Review

Computed tomography with its excellent spatial and temporal resolution remains a valuable diagnostic modality in pediatrics. On the other hand an increasing attention has been placed on the radiation risks associated with CT imaging, especially in children. In recent years, many advances in CT hardware and software, for example, automatic exposure control tools and iterative reconstruction techniques, have allowed for a reduction of applied radiation doses while maintaining image quality. The purpose of this paper is to present our protocol for chest CT imaging in the youngest age group, together with a pictorial review of congenital pathologies of the chest, and to emphasize factors that optimize postnatal CT imaging in infants. In our opinion, modern CT imaging with the use of dose reduction techniques and iterative reconstructions allows for a proper visualization of chest pathologies in small children, which has no influence on observer performance. The presented review of low-dose diagnostic images of a wide spectrum of congenital pathologies may serve as an example of routine utilization of the current concepts in pediatric CT optimization.

Sonography of the Pediatric Chest

Traditionally, pediatric chest diseases are evaluated with chest radiography. Due to advancements in technology, the use of sonography has broadened. It has now become an established radiation-free imaging tool that may supplement plain-film findings and, in certain cases, the first-line modality for evaluation of the pediatric chest. This pictorial essay will demonstrate the diagnostic potential of sonography, review a spectrum of pediatric chest conditions, and discuss their imaging features and clinical importance.

Imaging findings of bronchial atresia in fetuses, neonates and infants

Congenital lung malformations are increasingly detected before birth. However, bronchial atresia is rarely identified in utero and not always recognized in neonates. There are two types of atresia: 1) proximal, located at the level of the mainstem or the proximal lobar bronchi, which is extremely rare and usually lethal during pregnancy, causing a tremendous volume increase of the distal involved lung with secondary hypoplasia of the normal lung, and 2) peripheral, located at the segmental/subsegmental bronchial level, which may present as an isolated lesion or as part of a complex congenital malformation. Prenatal findings are mostly nonspecific. Postnatal exams show overinflated lung areas and focal bronchial dilations. The typical fluid-filled bronchoceles are not always observed in neonates but develop progressively in the first months of life. This pictorial essay describes the spectrum of imaging findings of bronchial atresia in fetuses, neonates and infants.

Prenatal and Postnatal Management of Congenital Pulmonary Airway Malformation

Congenital pulmonary airway malformation (CPAM) is one of the most common lung lesions detected prenatally. Despite the research efforts made in the past few years, controversy and lack of clarity in the literature still exist regarding nomenclature, classification, pathogenesis and the management of CPAM. Therefore, it is of greatest importance to delineate the natural history of CPAMs and to create a consensus to guide the management and follow-up of these lesions. This review will focus on classification systems, highlighting the most recent advancements in pathogenesis, and current practice in the prenatal diagnosis of CPAM. Strategies of prenatal management and postnatal management will be reviewed. Long-term follow-up, including lung cancer risk, is discussed and an outcome perspective is presented.

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

Congenital lung anomalies represent a diverse group of developmental malformations of the lung parenchyma, arterial supply, and venous drainage, which may present anywhere from the prenatal period through adulthood. It is imperative for radiologists to be aware of imaging techniques and imaging appearance of these anomalies across the pediatric age range. This review presents the spectrum of these lesions that are often encountered in daily clinical practice. Each anomaly is discussed in terms of underlying etiology, clinical presentation, and imaging characterization with emphasis on the most up-to-date research and treatment. Knowledge of these areas is essential for accurate, timely diagnosis, which aids in optimizing patient outcomes.

CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

BACKGROUND

Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants.

OBJECTIVE

To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions.

MATERIALS AND METHODS

A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDIvol was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups.

RESULTS

Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy).

CONCLUSION

Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose.

Vanishing fetal lung malformations: Prenatal sonographic characteristics and postnatal outcomes

BACKGROUND/PURPOSE

The purpose of this study was to examine the natural history and outcomes of prenatally diagnosed lung masses that appear to undergo complete regression before birth.

METHODS

An IRB-approved retrospective review was performed on 100 consecutive fetuses with a congenital lung malformation at a single fetal center. Prenatal and postnatal imaging as well as outcomes of vanishing fetal masses was analyzed and compared to those with persistent fetal masses.

RESULTS

Seventeen lesions (17%) became sonographically undetectable at 35.3 ± 2.3 weeks gestation. Vanishing fetal masses were associated with microcystic disease (100% vs. 69%, p=0.005) and a low initial congenital pulmonary airway malformation volume ratio (CVR; 0.31 ± 0.35 vs. 0.70 ± 0.66, p=0.002) when compared to those with persistent fetal lesions. Based on postnatal CT imaging and pathology data, 10.3% of all fetal masses completely regressed. The positive predictive value and negative predictive value of prenatal ultrasound for detecting lung malformations in late gestation were 96% and 43%, respectively. All infants with vanishing fetal lesions were asymptomatic at birth and were more likely to be managed nonoperatively (75% vs. 22%, p<0.0001) when compared to infants with persistent fetal masses.

CONCLUSIONS

Vanishing lung lesions late in gestation are relatively common and are associated with a low CVR and microcystic disease.

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.

Fetal Magnetic Resonance Imaging of Malformations Associated with Heterotaxy

Magnetic resonance imaging (MRI) is increasingly used as an investigation during fetal life, particularly for assessment of intracranial masses, congenital diaphragmatic hernia, myelomeningocele, and abdominal masses. As the number of scans increases, so is the variety of congenital malformations being recognized. It is axiomatic that interpretation of the findings is enhanced when attention is paid to the likely findings in the setting of known syndromes, this information then dictating the need for additional acquisition of images. One such syndrome is so-called "visceral heterotaxy", in which there is typically an isomeric, rather than a lateralized, arrangement of the thoracic and abdominal organs. Typically associated with complex congenital cardiac malformations, heterotaxy can also involve the central nervous system, and produce pulmonary, gastrointestinal, immunologic, and genitourinary malformations. In this review, we discuss how these findings can be demonstrated using fetal MRI.

Unusual signal intensity of congenital pulmonary airway malformation on fetal magnetic resonance imaging

Congenital pulmonary airway malformation (CPAM) is classified into pathologically different types. These types are sometimes distinguishable by fetal lung MRI and are usually observed as higher-signal lesions on T2-weighted images than normal lung. We describe a case of unusual CPAM resembling neoplasms, with a lower signal than is found in normal lung. Histopathology showed a large number of mucogenic cells but found no evidence that could explain this feature on fetal MRI. An unusual low-signal mass associated with a pulmonary cyst in fetal lung on MRI may suggest an unusual type 1 CPAM.

Role of SOX2 in foregut development in relation to congenital abnormalities

The uptake of the two essential ingredients for life, oxygen and nutrients, occurs primarily through the oral cavity, but these two lifelines need to be separated with high accuracy once inside the body. The two systems, the gas exchange pulmonary system and the gastro-intestinal feeding system, are derived from the same primitive embryonic structure during development, the foregut, which need to be separated before birth. In certain newborns, this separation occurs not or insufficiently, leading to life threatening conditions, sometimes incompatible with life. The development of the foregut, trachea and lungs is influenced and coordinated by a multitude of signaling cascades and transcription factors. In this review, we will highlight the development of the foregut and pulmonary system and focus on associated congenital abnormalities in light of known genetic alterations with specific attention to the transcription factor SOX2.

Outcomes of prenatally diagnosed lung lesions in multigestational pregnancies

BACKGROUND

The outcomes of prenatally diagnosed lung lesions in the context of multigestational pregnancies are unknown.

METHODS

Of 960 fetal lung lesion cases evaluated at a single tertiary center over 16 years, 30 occurred in multigestational pregnancies. We reviewed this series to aid in prenatal counseling of affected families and to provide prognostic information for decision making. Pre- and postnatal clinical characteristics were gathered for these pregnancies, and the morbidity and mortality were determined for both affected and normal fetuses, whether twins or triplets.

RESULTS

Mortality was found to be 3/30 (10%) for affected fetuses, and morbidity in normal co-twins was consistent with the degree of prematurity. No morbidity was seen in co-twins born at or after 36 weeks of gestation. Median gestational age at delivery was 35 5/7 weeks.

CONCLUSIONS

Outcomes for the affected fetus correlate with the size and pathophysiologic consequences of the lesion and are not worse than previously reported outcomes for similar lesions in singleton pregnancies, while morbidity in the normal co-twin is consistent with prematurity related to the fetal age of the multiple gestation at delivery, irrespective of the fetal lung lesion.

Cystic lung lesions in newborns and young children: differential considerations and imaging

Numerous diverse entities produce cystic lung changes in neonates and young children. This review provides an evidence-based, age-appropriate, differential diagnostic framework to use when confronted with pulmonary cystic changes. The categories of diseases that have been discussed include congenital cystic bronchopulmonary malformations, neoplastic conditions, infections, collagen or soft tissue abnormalities, and mimics of cystic lung disease. An understanding of the pathophysiology, imaging appearance, and demographics of these entities is essential in guiding optimal care. Important educational points include differentiating bronchopulmonary malformations from neoplasms and the management and surveillance of lung cysts in young children.

Computed tomography depiction of small pediatric vessels with model-based iterative reconstruction

BACKGROUND

Computed tomography (CT) is extremely important in characterizing blood vessel anatomy and vascular lesions in children. Recent advances in CT reconstruction technology hold promise for improved image quality and also reductions in radiation dose. This report evaluates potential improvements in image quality for the depiction of small pediatric vessels with model-based iterative reconstruction (Veo™), a technique developed to improve image quality and reduce noise.

OBJECTIVE

To evaluate Veo™ as an improved method when compared to adaptive statistical iterative reconstruction (ASIR™) for the depiction of small vessels on pediatric CT.

MATERIALS AND METHODS

Seventeen patients (mean age: 3.4 years, range: 2 days to 10.0 years; 6 girls, 11 boys) underwent contrast-enhanced CT examinations of the chest and abdomen in this HIPAA compliant and institutional review board approved study. Raw data were reconstructed into separate image datasets using Veo™ and ASIR™ algorithms (GE Medical Systems, Milwaukee, WI). Four blinded radiologists subjectively evaluated image quality. The pulmonary, hepatic, splenic and renal arteries were evaluated for the length and number of branches depicted. Datasets were compared with parametric and non-parametric statistical tests.

RESULTS

Readers stated a preference for Veo™ over ASIR™ images when subjectively evaluating image quality criteria for vessel definition, image noise and resolution of small anatomical structures. The mean image noise in the aorta and fat was significantly less for Veo™ vs. ASIR™ reconstructed images. Quantitative measurements of mean vessel lengths and number of branches vessels delineated were significantly different for Veo™ and ASIR™ images. Veo™ consistently showed more of the vessel anatomy: longer vessel length and more branching vessels.

CONCLUSION

When compared to the more established adaptive statistical iterative reconstruction algorithm, model-based iterative reconstruction appears to produce superior images for depiction of small pediatric vessels on computed tomography.

Magnetic resonance imaging of pediatric lung parenchyma, airways, vasculature, ventilation, and perfusion: state of the art

Magnetic resonance (MR) imaging is a noninvasive imaging modality, particularly attractive for pediatric patients given its lack of ionizing radiation. Despite many advantages, the physical properties of the lung (inherent low signal-to-noise ratio, magnetic susceptibility differences at lung-air interfaces, and respiratory and cardiac motion) have posed technical challenges that have limited the use of MR imaging in the evaluation of thoracic disease in the past. However, recent advances in MR imaging techniques have overcome many of these challenges. This article discusses these advances in MR imaging techniques and their potential role in the evaluation of thoracic disorders in pediatric patients.