Congenital abnormalities of intrathoracic airways

Pediatric large airway imaging: evolution and revolution

Infants and children often present with respiratory symptoms referable to the airway. For these pediatric patients, airway imaging is frequently performed to evaluate for underlying disorders of the large airway. Various imaging modalities have been used to evaluate the pediatric large airway, and pediatric airway imaging techniques have continued to evolve. Therefore, clear understanding of the status and new advances in pediatric large airway imaging is essential for practicing radiologists to make timely and accurate diagnoses, which can lead to optimal pediatric patient management.

Congenital anomalies of the large intrathoracic airways

Congenital lung lesions are numerous but rare in individual clinical practice. They do require close multidisciplinary collaboration between health care professionals. This educational review will focus on the pathophysiology, clinical manifestations, surgical approaches, and anesthetic management of congenital anomalies of the large intrathoracic airways: congenital tracheal stenosis, tracheal agenesis, tracheal diverticulum, bronchial anomalies (tracheal, esophageal, or bridging bronchus), congenital lung malformations, lung sequestrations and Scimitar syndrome, lobar emphysema, Williams-Campbell syndrome, and pleuropulmonary blastoma. In addition, this review will illustrate common pitfalls and challenges related to the anesthesia management with emphasis on ventilation and correct endotracheal tube positioning.

Determining normal values for lower trachea and bronchi size in children by computed tomography (CT)

BACKGROUND

Normative data for central airway dimensions are a prerequisite to objectively assess large airway pathologies. Studies with computed tomography (CT) measurements of normal trachea and bronchi size in children are scarce.

OBJECTIVE

The purpose of this study is to establish normal values of central airway dimensions in children by CT.

METHODS

The study included chest CT studies from children aged 0-18 years. Any condition that predisposed the patient to have an abnormal tracheal or bronchial size was excluded. Airway diameters and cross-sectional area (CSA) were measured using double oblique reconstructions at five levels: proximal trachea, mid-trachea, distal trachea, right main bronchus, and left main bronchus.

RESULTS

The inclusion criteria were met by 110 subjects (mean age, 10.8 years; SD, 5.2 years). Various regression models that considered the relationship between patient demographics and anteroposterior (AP) diameter, transverse diameter, and CSA at each of the five levels were assessed. R² was utilized to select the best model. Multiple formulae (using patient age) were developed to calculate expected normal dimensions for five levels in the central airways on the natural log scale. Finally, z-scores were obtained for central airway dimensions at these five levels.

CONCLUSION

Normative data in pediatric central airways are crucial to identify large airway pathologies. We propose using the formulae devised in our study to calculate the predicted dimensions of central airways and their z-scores in pediatric patients. Normative data from our study will aid in objective quantification of central airways, increase clinician confidence, and provide appropriate patient care.

Asymptomatic left isomerism with preduodenal portal vein: computed tomography appearance

Left isomerism (polysplenia), one of the two major variants of heterotaxia with right isomerism (asplenia), may be rarely diagnosed in adulthood. Most cases are nevertheless asymptomatic and incidentally detected during imaging or surgery performed for unrelated conditions. We hereby report a case of left isomerism fortuitously diagnosed in a 55-year-old man with unrelated tachy-cardiomyopathy. Thoraco-abdominal computed tomography revealed a typical preduodenal portal vein (PDPV) associated with a large series of other occult anatomic variations comprising: polysplenia, agenesis of both pancreatic body and tail, complete non-rotation of the bowel and finally azygous continuation of the inferior vena cava. Subtle but highly specific thoracic features of left isomerism were also found with a bilobed right lung and bilateral long hyparterial main bronchi. The features of adult left isomerism are remembered with special attention to the PDPV.

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.

Changes of intrathoracic trachea with respiration in children: A metrical assessment based on 3D CT models

AIM

To assess the tracheal volume and the effect of respiration through segmentation on CT-scans in children.

MATERIAL AND METHODS

Chest-CT of 100 patients divided into males and females, aged 3-16 years, were retrospectively assessed. Subjects underwent inspiratory and expiratory CT-scans. Tracheal volume was segmented through ITK-SNAP software. Volume, length, anteroposterior, laterolateral diameters, and T1-T10 distance were measured. The percentage ratio between expiratory and inspiratory phases was calculated: significant differences according to sex for inspiratory and expiratory measurements were assessed through a one-way ANCOVA test using T1-T10 distance as covariate (p < 0.05). Differences in percentage changes according to sex and age were assessed through Mann-Whitney test and calculation of Pearson's correlation coefficient, respectively (p < 0.05).

RESULTS

No statistically significant difference according to sex was found for any measurement (p > 0.05). For the percentage ratio between inspiratory and expiratory phase, no difference was found according to sex for any measurement (p > 0.05). The percentage ratio of tracheal volume and length between expiratory and inspiratory phases showed a negative correlation with age (p < 0.05).

CONCLUSIONS

This study provides a novel contribution to the assessment of tracheal size in healthy children: future studies will verify the same measurements in patients affected by tracheomalacia to improve diagnosis.

Congenital Anomalies of the Tracheobronchial Tree: A Meta-Analysis and Clinical Considerations

BACKGROUND

The aim of this study was to determine the prevalence and anatomic features of major tracheobronchial anomalies.

METHODS

Major electronic databases were systematically searched to identify eligible studies. Data were extracted and pooled into a meta-analysis. The primary outcome was the prevalence of major tracheobronchial anomalies, specifically tracheal bronchus (TB) and accessory cardiac bronchus (ACB). Secondary outcomes included the origin and types of TB and ACB.

RESULTS

A total of 27 studies (n = 119,695 patients) were included. A TB was present in 0.99% (95% confidence interval, 0.67 to 1.37) of patients, and an ACB was present in 0.14% (95% confidence interval, 0.09 to 0.20). The overall prevalence of TB was higher in imaging than in operative studies (1.81% vs 0.82%). It was also higher in pediatric (2.55%) than in adult studies (0.50%). Patients with other congenital anomalies were 15 times more likely to have a TB (odds ratio 14.89; 95% confidence interval, 7.09 to 31.22). The most common origin of TBs was from the trachea (81.42%), primarily from the right side (96.43%). The most common origin of ACBs was from the intermediate bronchus (74.32%). The ACBs terminated as blind-ending diverticulum in two thirds of cases.

CONCLUSIONS

Major tracheobronchial anomalies are present in approximately 1% of the population, although the prevalence is higher among pediatric patients and patients with accompanying congenital anomalies. Although rare, major tracheobronchial anomalies can be associated with significant respiratory morbidities and present challenges during airway management in surgical and critical care patients. Establishing a preoperative diagnosis of these variations is essential for planning and implementing an appropriate airway management strategy to minimize attendant complications.

Bridging bronchus (pseudocarina) and left pulmonary artery sling: A case report and literature review

Congenital airway malformations can present with respiratory distress, cyanosis, and difficulty feeding in the neonate or infant. Clinical presentation may vary from asymptomatic to fatal airway obstruction. They may exist in isolation or in association with vascular rings and slings, bronchopulmonary malformations, and/or syndromes. We present an unusual case of bridging bronchus, complete bronchial rings, and left pulmonary artery sling presenting with recurrent croup, highlighting the importance of bronchoscopy and CT imaging to achieve an accurate diagnosis in patients with recurrent croup and/or respiratory failure not responding to usual treatment measures and a multidisciplinary treatment approach.

Tracheal bronchus diagnosed in children undergoing flexible bronchoscopy

This paper describes the clinical features of paediatric patients with tracheal bronchus (TB) identified with flexible bronchoscopy (FB) in a tertiary care hospital. A retrospective review of every FB with diagnosis of TB carried out in our centre since 1990 was performed which considered specifically: age at diagnosis, gender, semiology, somatic anomalies, tracheal bronchus type, other bronchoscopic findings and clinical progress. Out of 1665 FB in 1337 patients, TB was found in 26 (1.9%). The median age was 15 months (age range 1 month-13 years), with no gender differences. Of 26 patients, a total of 24 had associated congenital pathologies (92.3%) (heart disease 69%, chromosomal abnormality 35% and spinal fusion defect 11%). FB was performed for a number of reasons including: recurrent or persistent wheezing, pneumonia or atelectasis, persistent stridor and refractory cough. The type of TB identified was primarily ectopic lobar of the right upper lobe (73%) and the apical supernumerary (11.5%). In addition to TB, other defects were found by FB in 90% of cases, such as tracheomalacia, bronchomalacia or tracheal stenosis. The review confirmed a higher prevalence of TB than expected in previous series and highlighted its association with other airway or somatic malformations, notably congenital cardiac defects and spinal fusion defects. All patients were managed conservatively for the TB.

Intraoperative anesthetic management of an infant with a bridging bronchus: A case report

A newborn infant was diagnosed with an imperforate anus, and colostomy was performed one day after birth. He exhibited repeated episodes of poor oxygenation during intubation, and a CT scan revealed a bridging bronchus. He was scheduled to undergo sacroperineal repair in the prone position 8 months later. A tracheal tube, with its tip modified to widen the opening, was inserted through the nose. This led to normal oxygenation, even while in the prone position. The surgery was completed without any complications.

Airflow in Tracheobronchial Tree of Subjects with Tracheal Bronchus Simulated Using CT Image Based Models and CFD Method

Tracheal Bronchus (TB) is a rare congenital anomaly characterized by the presence of an abnormal bronchus originating from the trachea or main bronchi and directed toward the upper lobe. The airflow pattern in tracheobronchial trees of TB subjects is critical, but has not been systemically studied. This study proposes to simulate the airflow using CT image based models and the computational fluid dynamics (CFD) method. Six TB subjects and three health controls (HC) are included. After the geometric model of tracheobronchial tree is extracted from CT images, the spatial distribution of velocity, wall pressure, wall shear stress (WSS) is obtained through CFD simulation, and the lobar distribution of air, flow pattern and global pressure drop are investigated. Compared with HC subjects, the main bronchus angle of TB subjects and the variation of volume are large, while the cross-sectional growth rate is small. High airflow velocity, wall pressure, and WSS are observed locally at the tracheal bronchus, but the global patterns of these measures are still similar to those of HC. The ratio of airflow into the tracheal bronchus accounts for 6.6-15.6% of the inhaled airflow, decreasing the ratio to the right upper lobe from 15.7-21.4% (HC) to 4.9-13.6%. The air into tracheal bronchus originates from the right dorsal near-wall region of the trachea. Tracheal bronchus does not change the global pressure drop which is dependent on multiple variables. Though the tracheobronchial trees of TB subjects present individualized features, several commonalities on the structural and airflow characteristics can be revealed. The observed local alternations might provide new insight into the reason of recurrent local infections, cough and acute respiratory distress related to TB.

Robot-assisted lobectomy for lung cancer in the presence of intraoperatively discovered broncho-vascular anomalies affecting right upper and middle lobes

Anatomical variations of the pulmonary bronchi and vessels can lead to serious intraoperative complications during minimally invasive surgery if overlooked. We describe the intraoperative management of an exceptional bronco-vascular variation of the right upper and middle lobe revealed during robotic lobectomy.

Pediatric Thoracic Anatomic Variants: What Radiologists Need to Know

Anatomic variants are common incidental findings in pediatric chest imaging and can be mistaken for true underlying pathology, sometimes resulting in unnecessary additional imaging evaluation or invasive procedures. Clear understanding of the imaging characteristics and clinical significance of anatomic thoracic variants is important for accurate diagnosis and avoidance of unnecessary intervention. This article provides an up-to-date review of anatomic variants in the pediatric chest to increase knowledge and aide in timely, correct diagnosis.

Prevalence of the Accessory Cardiac Bronchus on Multidetector Computed Tomography: Evaluation and Proposed Classification

PURPOSE

Accessory cardiac bronchus (ACB) is a very rare congenital anomaly and may cause some clinical complications, such as recurrent episodes of both infection and hemoptysis. The purpose of this study was to assess the multidetector computed tomography (MDCT) characteristics of ACB and to classify this anomaly according to the MDCT aspects.

MATERIALS AND METHODS

The routine thoracic CT scans from 5790 patients were evaluated retrospectively. The prevalence, location, length, diameter, division angle, distance from the carina, and the type of ACB were evaluated.

RESULTS

A total of 12 ACBs were identified, with a prevalence of 0.2%. All ACBs originated from the intermediate bronchus. The median largest diameter of the ACBs was 7.75 mm (range: 5.8 to 10.30 mm), the median length was 12.1 mm (range: 8.6 to 35 mm), the median division angle was 61 degrees (range: 42 to 93 degrees), and the median distance from the carina was 16.95 mm (range: 5.7 to 22.20 mm). Six cases (50%) had a blind extremity (type 1: diverticulum or stump type), 3 cases (25%) had a mutiloculated cystic change at the end (type 2: cystic type), and 3 cases (25%) had a ventilated lobulus demarcated by an anomalous fissure (type 3: ventilated type).

CONCLUSIONS

ACBs can be classified into 3 types according to their MDCT features. Recognition of ACB is important, as it is associated with clinical complications and is also salient in trauma cases.

A 28-Year-Old Woman With Branching Opacity and Chest Pain

A 28-year-old female patient presented through her primary care physician with symptoms of atypical chest pain and chronic cough. Her pain was described as pleuritic and intermittently radiating to the right arm. Her medical history was significant for recurrent respiratory infections, gastritis, and a left ovarian cyst treated with ipsilateral salpingo-oophorectomy. She denied any history of smoking, known lung disease, or extrapulmonary infections.

Hoxa5: A Key Player in Development and Disease

A critical position in the developmental hierarchy is occupied by the Hox genes, which encode transcription factors. Hox genes are crucial in specifying regional identity along the embryonic axes and in regulating morphogenesis. In mouse, targeted mutations of Hox genes cause skeletal transformations and organ defects that can impair viability. Here, we present the current knowledge about the Hoxa5 gene, a paradigm for the function and the regulation of Hox genes. The phenotypic survey of Hoxa5-/- mice has unveiled its critical role in the regional specification of the skeleton and in organogenesis. Most Hoxa5-/- mice die at birth from respiratory distress due to tracheal and lung dysmorphogenesis and impaired diaphragm innervation. The severity of the phenotype establishes that Hoxa5 plays a predominant role in lung organogenesis versus other Hox genes. Hoxa5 also governs digestive tract morphogenesis, thyroid and mammary glands development, and ovary homeostasis. Deregulated Hoxa5 expression is reported in cancers, indicating Hoxa5 involvement in tumor predisposition and progression. The dynamic Hoxa5 expression profile is under the transcriptional control of multiple cis-acting sequences and trans-acting regulators. It is also modulated by epigenetic mechanisms, implicating chromatin modifications and microRNAs. Finally, lncRNAs originating from alternative splicing and distal promoters encompass the Hoxa5 locus.

Tracheobronchial Branching Abnormalities: Lobe-based Classification Scheme

Boyden's nomenclature, which was based on postmortem specimens and published in 1955 prior to the advent of computed tomography (CT), is commonly used to describe the normal segmental bronchial anatomy and various abnormalities. However, several additional anomalies have been recognized since that time, and there is some confusion over the names used to describe these anomalies. Several congenital branching anomalies affecting the trachea, main bronchi, and intermediate bronchus have been reported, all of which can be recognized at chest CT but are often overlooked. These anomalies, which probably occur early in fetal life, can be either supernumerary, with defects occurring at 29-30 days gestation, or displaced, with defects occurring later. Tracheobronchial positional anomalies are often associated with other congenital abnormalities but may be isolated. They often are asymptomatic but can be responsible for pulmonary symptoms such as dyspnea, recurrent pneumonia, and hemoptysis. It is essential that these anomalies are recognized prior to lung resection to avoid complications, especially when video-assisted thoracoscopic surgery is performed. In addition, bronchoscopists should be aware of these anomalies before performing diagnostic or therapeutic bronchoscopic procedures. Awareness of a few key bronchial anatomic principles and use of a lobe-based classification scheme will facilitate recognition of tracheobronchial positional anomalies.

Teaching basic lung isolation skills on human anatomy simulator: attainment and retention of lung isolation skills

Background

Lung isolation skills, such as correct insertion of double lumen endobronchial tube and bronchial blocker, are essential in anesthesia training; however, how to teach novices these skills is underexplored. Our aims were to determine (1) if novices can be trained to a basic proficiency level of lung isolation skills, (2) whether video-didactic and simulation-based trainings are comparable in teaching lung isolation basic skills, and (3) whether novice learners’ lung isolation skills decay over time without practice.

Methods

First, five board certified anesthesiologist with experience of more than 100 successful lung isolations were tested on Human Airway Anatomy Simulator (HAAS) to establish Expert proficiency skill level. Thirty senior medical students, who were naive to bronchoscopy and lung isolation techniques (Novice) were randomized to video-didactic and simulation-based trainings to learn lung isolation skills. Before and after training, Novices’ performances were scored for correct placement using pass/fail scoring and a 5-point Global Rating Scale (GRS); and time of insertion was recorded. Fourteen novices were retested 2 months later to assess skill decay.

Results

Experts’ and novices’ double lumen endobronchial tube and bronchial blocker passing rates showed similar success rates after training (P >0.99). There were no differences between the video-didactic and simulation-based methods. Novices’ time of insertion decayed within 2 months without practice.

Conclusion

Novices could be trained to basic skill proficiency level of lung isolation. Video-didactic and simulation-based methods we utilized were found equally successful in training novices for lung isolation skills. Acquired skills partially decayed without practice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-015-0169-7) contains supplementary material, which is available to authorized users.

Imaging of Large Airways Disorders

OBJECTIVE

Recent technical advances, including the routine use of CT thin sections and techniques such as 2D minimum-intensity-projection and 3D volume images, have increased our ability to detect large airways diseases. Furthermore, dedicated CT protocols allow the evaluation of dynamic airway dysfunction.

CONCLUSION

With diseases of the large airways more commonly seen in daily practice, it is important that radiologists be familiar with the appearances, differential diagnosis, and clinical implications of these entities.

Bridging bronchus: Importance of recognition on airway endoscopy

Bridging bronchus is an anomalous bronchus, which crosses the mediastinum from the contralateral mainstem bronchus and it is commonly associated with congenital great vessel abnormalities. This is a case report of an infant that underwent airway endoscopy and attempt at cannulation of a mainstem bronchus with supposed bronchial cast after cardiac surgery in the intensive care unit. After multiple failed attempts, further workup was completed which revealed a bridging bronchus. A bridging bronchus must be suspected in a patient with abnormal appearing endoscopy in presence of great vessel anomalies to prevent accidental injury to the tracheobronchial tree.

Imaging of the central airways with bronchoscopic correlation: pictorial essay

A wide variety of pathologic processes, both benign and malignant, affect the central airways. These processes may be classified into 4 distinct groups: anatomic variants, lesions that result in focal or diffuse airway narrowing, and those that result in multinodular airway disorder. Key to the accurate assessment of the central airways is meticulous imaging technique, especially the routine acquisition of contiguous high-resolution, 1-mm to 1.5-mm images. These images enable high-definition axial, coronal, and sagittal reconstructions, as well as advanced imaging techniques, including minimum intensity projection images and virtual bronchoscopy. Current indications most commonly include patients presenting with signs and symptoms of possible central airway obstruction, with or without hemoptysis. In addition to diagnosing airway abnormalities, computed tomography (CT) also serves a critical complementary role to current bronchoscopic techniques for both diagnosing and treating airway lesions. Advantages of CT include noninvasive visualization of the extraluminal extent of lesions, as well as visualization of airways distal to central airways obstructions. As discussed and illustrated later, thorough knowledge of current bronchoscopic approaches to central airway disease is essential for optimal correlative CT interpretation.

Child chest trauma with hypogenetic lung

Trauma patients with hypogenetic lung could be difficult to diagnose and confused with post trauma haemothorax. This can lead to insertion of intercostal drain and result in serious iatrogenic injury. Differentiation between hypogenetic lung disease and haemothorax sometimes requires additional investigations like ultrasound scan or computed tomography.

Accessory cardiac bronchus

Accessory cardiac bronchus is a poorly recognized, usually asymptomatic, congenital abnormality of the bronchial tree. Recognition of bronchial anomalies is important since they are associated with clinical complications including recurrent episodes of infection, hemoptysis, and in some cases malignancy.

Complete tracheal duplication with unilateral atelectasis in an adult

Duplication of the trachea is an extremely rare condition that has been infrequently reported in the medical literature. We report an adult case with complete tracheal duplication associated with unilateral atelectasis, which was incidentally detected by computed tomography. Tracheal duplication should be considered as a possible cause of severe atelectasis in adults.

Current trends in cardiac CT in children

Cardiac CT is increasingly utilized in children thanks to advanced scan techniques reducing cardiac and respiratory motion artifacts. Consequently, clinical indications of cardiac CT are not confined to the extracardiac evaluation and extended further to the assessment of intracardiac structures, coronary arteries, ventricular volumetry, and ventricular function. In addition, dual-energy CT allows the assessment of regional lung perfusion and ventilation. Four-dimensional airway evaluation is also useful and may be added to cardiac CT protocols. At the same time, a favorable risk-benefit ratio of cardiac CT can be achieved by means of various dose-saving techniques. Therefore, flexible scan techniques with minimal motion artifacts, low dose techniques without compromising excellent image quality, and extended clinical applications towards truly cardiac assessments constitute current trends in cardiac CT in children.

Congenital anomaly of combined tracheal and accessory cardiac bronchus

The presence of congenital tracheobronchial abnormalities remain rare and have been reported to range from 0.1% to 2% in the literature. The most commonly described abnormalities are the tracheal bronchus and the accessory cardiac bronchus. We present the case of a 67-year-old man presenting for evaluation of interstitial lung disease, on computed tomography found to have presence of both the anomalies; the findings later confirmed on bronchoscopy. We believe this report is important as it adds more descriptive information regarding this unusual presentation, including bronchoscopic and computed tomographic images. We believe that it is imperative that bronchoscopists are cognizant of these congenital abnormalities and their combinations. Inability to properly characterize these abnormalities has a potential leading to unnecessary investigations of these relatively benign entities.

Extralobar pulmonary sequestration in a 55-year-old man

Pulmonary sequestration is a rare congenital lung malformation that more commonly occurs in the left lung, mainly near the lower mediastinum. It is rarely observed in patients with extralobar sequestration in adulthood. We report the case of a 55-year-old man with recurrent fever and cough lasting for about 1 month, who was admitted to our hospital. His past history was unremarkable. The final diagnosis of extralobar sequestration was dependent on three-dimensional computed tomography angiography (3D CTA), which showed an abnormal blood supply vessel to the consolidation from the aortic arch. The patient underwent a left pulmonary sequestration resection, and the pathological examination also verified the diagnosis postoperatively. 3D CTA images can provide an aberrant vessel anatomy map for the surgeon and play a decisive role in the detection of pulmonary sequestration.

CT findings of a displaced left upper division bronchus in adults: its importance for performing safe left pulmonary surgery

PURPOSE

The aim of this study was to describe the CT findings of a displaced left upper division bronchus (DLUDB) in adults.

MATERIALS AND METHODS

Ten patients with DLUDB were identified. The following CT features were assessed: origin of the DLUDB; distance between the origin of the DLUDB and the origin of the left upper lobe (LUL) bronchus; height of the origin of the DLUDB against the left pulmonary artery (LPA); difference of the main bronchial length; ventilated segment; course of the left pulmonary artery against the DLUDB; and presence of an accessory fissure or other anomalies.

RESULTS

DLUDB arose from the posterolateral or lateral aspect of the left main bronchus immediately proximal to the origin of the LUL bronchus. It tended to course along the posterior wall of the LPA and to ventilate the apicoposterior segment with or without the anterior segment. The LPA passed between the displaced bronchus and the lingular bronchus. The origin of the DLUDB was located lower than the inferior wall of the proximal LPA in 6 patients. The accessory fissure between the associated segment and remaining part of the LUL and right tracheal bronchus coexisted in 7 and 3 patients respectively.

CONCLUSION

DLUDB has characteristic findings on CT. Radiologists should be aware of this entity and inform the surgeon as it can prevent serious complications in a patient who may undergo lobectomy of the left lung.

Signaling through BMP receptors promotes respiratory identity in the foregut via repression of Sox2

The mammalian foregut gives rise to the dorsally located esophagus and stomach and the ventrally located trachea and lung. Proper patterning and morphogenesis of the common foregut tube and its derived organs is essential for viability of the organism at birth. Here, we show that conditional inactivation of BMP type I receptor genes Bmpr1a and Bmpr1b (Bmpr1a;b) in the ventral endoderm leads to tracheal agenesis and ectopic primary bronchi. Molecular analyses of these mutants reveal a reduction of ventral endoderm marker NKX2-1 and an expansion of dorsal markers SOX2 and P63 into the prospective trachea and primary bronchi. Subsequent genetic experiments show that activation of canonical WNT signaling, previously shown to induce ectopic respiratory fate in otherwise wild-type mice, is incapable of promoting respiratory fate in the absence of Bmpr1a;b. Furthermore, we find that inactivation of Sox2 in Bmpr1a;b mutants does not suppress ectopic lung budding but does rescue trachea formation and NKX2-1 expression. Together, our data suggest that signaling through BMPR1A;B performs at least two roles in early respiratory development: first, it promotes tracheal formation through repression of Sox2; and second, it restricts the site of lung bud initiation.

Update on multidetector computed tomography imaging of the airways

Recent advances in multidetector computed tomography (MDCT) technology have transformed the imaging evaluation of the trachea and bronchi. Multiplanar 2-dimensional and 3-dimensional volume reconstruction techniques, including external rendering and virtual bronchoscopy, can be generated in mere minutes, thereby complementing conventional axial CT imaging in the depiction of various central airway disease processes including airway stenoses, central airway neoplasms, and congenital airway disorders. Paired inspiratory and dynamic expiratory MDCT imaging, along with newer cine CT imaging methods, have enhanced the assessment of tracheobronchomalacia in both adults and the pediatric population. In addition, MDCT imaging plays an essential complementary role to conventional bronchoscopy, facilitating planning and guidance of bronchoscopic interventions, and providing a noninvasive method for postprocedural surveillance.

[Usefulness of chest CT in the diagnosis of pulmonary sequestration]

Pulmonary sequestration is a rare congenital anomaly, characterized by nonfunctional embryonic pulmonary tissue. Pulmonary sequestration accounts for 0.15-6.40% of all congenital pulmonary malformations. This anomaly, which is classified as intralobar or extralobar, involves the lung parenchyma and its vascularization. We report the case of a 56-year-old male presenting with hemoptysis. A chest X-ray showed an area of opacity behind the cardiac silhouette in the base of the left hemithorax. Chest CT scans with intravenous contrast revealed pulmonary sequestration. The patient underwent surgery, in which the anomalous tissue was successful resected. The postoperative evolution was favorable, and the patient was discharged to outpatient treatment.