Bronchial Branching Research Articles

Multi-slice computed tomographic analysis and identification of remarkable anatomical types of segmental bronchi in bilateral inferior lobes: based on extensive data.

The progress of interventional respiratory medicine necessitates a comprehensive knowledge of the segmental bronchi because of their complexity in branching patterns. Therefore, based on extensive research data, we aimed to examine the anatomical diversity and sex-related variations of the segmental bronchial branching patterns in the bilateral inferior lobes. Following the exclusion and inclusion criteria, a total of 10,000 participants who underwent multi-slice computed tomography (MSCT) scans from September 2019 to December 2021 at Cheeloo College of Medicine, Shandong University were enrolled in this retrospective study. The computed tomography (CT) data were utilized to generate three-dimensional (3D) and virtual bronchoscopy (VB) simulations of a bronchial tree using the syngo.via post-processing workstation. The distinct bronchial patterns in the bilateral inferior lobes were then found and categorized using the reconstructed images. The proportions of different types of bronchial branches and their sex-related correlations were analyzed by cross-tabulation and chi-square analysis. Our findings primarily identified four types of bronchial branching patterns in the right inferior lobe (RIL), i.e., (B6, B7, B8, B9+10), 71.44%; (B6, B7, B8+9, B10), 16.06%; (B6, B7+8, B9+10), 7.40%; (B6, B7, B8+9+10), 5.10%; and four types in the left inferior lobe (LIL), i.e., (B6, B7+8, B9+10), 82.89%; (B6, B7+8, B9, B10), 13.53%; (B6, B7, B8+9, B10), 2.88%; (B6, B7, B8+9+10), 0.70%. Besides various research methods and outcomes, this study has revealed the types of bronchial branches that were not seen in previous studies. In addition, the proportion of bronchial branches in the LIL did not differ significantly between males and females (P>0.05). However, there was a significant difference in the proportion of bronchial branches in the RIL between sexes (P<0.05). The current study has validated the segmental bronchial variations in the bilateral inferior lobes. The diagnosis of symptomatic patients as well as the performance of interventions like bronchoscopies, endotracheal intubation, and lung resections may be significantly influenced by our findings in the clinical setting.

Bronchial tree of the human embryo: Examination based on a mammalian model.

The symmetry of the right and left bronchi, proposed in a previous comparative anatomical study as the basic model of the mammalian bronchial tree, was examined to determine if it applied to the embryonic human bronchial tree. Imaging data of 41 human embryo specimens at Carnegie stages (CS) 16-23 (equivalent to 6-8 weeks after fertilization) belonging to the Kyoto collection were obtained using phase-contrast X-ray computed tomography. Three-dimensional bronchial trees were then reconstructed from these images. Bronchi branching from both main bronchi were labeled as dorsal, ventral, medial, or lateral systems based on the branching position with numbering starting cranially. The length from the tracheal bifurcation to the branching point of the labeled bronchus was measured, and the right-to-left ratio of the same labeled bronchus in both lungs was calculated. In both lungs, the human embryonic bronchial tree showed symmetry with an alternating pattern of dorsal and lateral systems up to segmental bronchus B9 as the basic shape, with a more peripheral variation. This pattern is similar to that described in adult human lungs. Bronchial length increased with the CS in all labeled bronchi, whereas the right-to-left ratio was constant at approximately 1.0. The data demonstrated that the prototype of the human adult bronchial branching structure is formed and maintained in the embryonic stage. The morphology and branching position of all lobar bronchi and B6, B8, B9, and the subsegmental bronchus of B10 may be genetically determined. On the other hand, no common structures between individual embryos were found in the peripheral branches after the subsegmental bronchus of B10, suggesting that branch formation in this region is influenced more by environmental factors than by genetic factors.

Bronchial Branching Patterns and Volumetry in the Right Upper Lobe: Impact on Segmentectomy Planning.

The use of segmentectomy is expected to increase. However, understanding of the segmental bronchial branching is limited. Herein, we aimed to investigate bronchial branching pattern complexity and segmental volumetry of the right upper lung lobe to develop an accurate understanding of segmental anatomy and contribute to the advancement of safe and efficient lung segmentectomy. We evaluated chest computed-tomography scans of 303 patients and categorized the branching of segmental bronchi (segment 1, apical; segment 2, posterior; and segment 3, anterior) into four major types (Typical trifurcated, bifurcated non-defective, bifurcated defective and Atypical trifurcated) and 11 subtypes. Segmental volumetry was performed to determine the predominant segment in each case (volume difference <5% was considered equal). Branching complexity was evaluated separately for volumetry-predominant and volumetry-non-predominant segments. Trifurcated non-defective was the most frequent branching type (64.4%), followed by bifurcated non-defective (22.1%), bifurcated defective (8.6%), and trifurcated half-defective (4.0%). In terms of segmental volumetry, most cases had a one-segment-predominant distribution (71%) and only 5% of cases had equal distribution (segment 1 = segment 2 = segment 3). More than half of the cases had a segment 3-predominant distribution (52%). Branching complexity analysis revealed that the volumetry-non-predominant segment was associated with a higher risk of complex branching patterns compared with the volumetry-predominant segment (37% vs 19%, respectively; p < 0.005). Volumetric assessment of the right upper lobe showed a heterogeneous segmental volume distribution. Care should be taken during lung segmentectomy of the volumetry-non-predominant segments because of the high risk associated with complex bronchial branching patterns. No. 4840.

Secretoglobin 3A2 protects lung from developing cigarette smoke-induced pulmonary emphysema.

Secretoglobin (SCGB) 3A2 is a bioactive molecule exhibiting various functions such as improving allergic airway inflammation and pulmonary fibrosis and promoting bronchial branching and proliferation during lung development. To determine if and how SCGB3A2 is involved in chronic obstructive pulmonary disease (COPD), a multifactorial disease with both airway and emphysematous lesions, a COPD mouse model was created by exposing Scgb3a2-deficient (KO), Scgb3a2-lung-specific overexpressing (TG), and wild type (WT) mice to cigarette smoke (CS) for 6 months. The KO mice showed loss of lung structure under control condition, and CS exposure resulted in more expansion of airspace and destruction of alveolar wall than WT mouse lungs. In contrast, TG mouse lungs showed no significant changes after CS exposure. SCGB3A2 increased the expression and phosphorylation of signal transducers and activators of transcription (STAT)1 and STAT3, and the expression of α1-antitrypsin (A1AT) in mouse lung fibroblast-derived MLg cells and mouse lung epithelial-derived MLE-15 cells. In MLg cells, A1AT expression was decreased in Stat3-knockdown cells, and increased upon Stat3 overexpression. STAT3 formed a homodimer when cells were stimulated with SCGB3A2. Chromatin immunoprecipitation and reporter assays demonstrated that STAT3 binds to specific binding sites on the Serpina1a gene encoding A1AT and upregulates its transcription in lung tissues of mice. Furthermore, nuclear localization of phosphorylated STAT3 upon SCGB3A2 stimulation was detected by immunocytochemistry. These findings demonstrate that SCGB3A2 protects the lungs from the development of CS-induced emphysema by regulating A1AT expression through STAT3 signaling.

Left Bronchial Isomerism with Right-Sided Tracheal Bronchus: A Rare Case Report

The tracheal bronchus is a congenital bronchial branching anomaly defined as an aberrant bronchus arising in either the trachea or a main bronchus. Left bronchial isomerism is characterized by two bilobed lungs, bilateral long main bronchi, and both pulmonary arteries passing superiorly to their respective upper lobe bronchi. Left bronchial isomerism with a right-sided tracheal bronchus is a very rare combination of tracheobronchial anomalies. It has not been previously reported. We present multi-detector CT findings of a left bronchial isomerism with a right-sided tracheal bronchus of a 74 year old man.

Hypogenetic Right Lung with Partial Anomalous Pulmonary Venous Return (PAPVR) Without the Typical Features of “Scimitar” Sign

The partial anomalous pulmonary venous return (PAPVR) aka partial anomalous pulmonary venous connection (PAPVC), is a rare congenital cardiovascular condition in which some of the pulmonary veins, drain into the systemic circulation (Halasz, 1956). While congenital, there is no known cause was attributed for these conditions and may possibly be multifactorial in origin. Scimitar syndrome, first described by Raoul Chassinat in 1836, is a variant of the PAPVR and PAPVC characterized by an abnormal pulmonary venous return of the right lung into the inferior vena cava or right atrium via the superior vena cava (SVC), thus a left‐to‐right shunt. Hypoplasia of the pulmonary arteries and abnormal bronchial branching accompany this syndrome and the abnormal venous drainage involves the right side.This report is based on the cadaveric dissection of a 71‐year old Caucasian male donor who died of chronic obstructive pulmonary disease/hypertension. We noted a faint incisional scar on the thorax, there was an incision extending from the parasternal region at the 4th intercostal level to the midaxillary line. Considering the straight‐line incision followed the ribs and the faintness of the scar was faint, we believe the surgery was done when the donor was young. We also observed numerous surgical interventions of the heart, lungs and vasculature to correct various defects.The morphology of the heart was normal, but was shifted more to the right side. An atrial septal defect (ASD) was closed with sutures. The right superior pulmonary vein that drained into the SVC was ligated close to the SVC. We noticed a dilated coronary sinus entering the right atrium adjacent to the ASD and the ostium of the coronary sinus noticeably lacked the normal valve like structure. We initially thought the right lung was a “horseshoe” lung but realized that it was a “hypogenetic” lung with PAPVR and an accessory diaphragm. The right secondary bronchi were much narrower compared to the left and branched uncharacteristically as seen in hypogenetic lung syndrome. The inferior lobe was highly disorganized, severely hypoplastic and exhibited uncharacteristic morphology. The superior bronchopulmonary segment was markedly hypoplastic. The medial basal segment was not only hypoplastic and slender but extended like a tail to the left pulmonary cavity behind the heart/pericardium and in front of esophagus and aorta. The right lung though hypoplastic, demonstrated patent bronchi and the lobes were inflatable. The superior pulmonary vein from the right upper and middle lobes drained directly into the SVC and the inferior right pulmonary vein from the lower lobe drained into the left atrium. The left superior and inferior pulmonary veins drain directly into the left atrium.The poster will illustrate numerous images as described in our results, discuss the embryology of pulmonary veins, hypogenetic lung, “scimitar” syndrome and accessory diaphragm. To sustain life, all the defects were corrected in childhood which allowed the donor to live for 71 years.

Role of indocyanine green in anomalous arterial supply to the normal dorsobasal segment of the lung

BackgroundAnomalous systemic arterial supply to normal basal lung segments is a rare congenital malformation, in which aberrant arteries arising from the systemic circulation flow into the basal segment of the lung and return to normal pulmonary veins without abnormal bronchial branching. It presents a left-to-right shunt, resulting in volume overload of the pulmonary circulation, and consequently, pulmonary hypertension. Therefore, nearly all cases require surgery. Herein, we present a case, in which indocyanine green was used to demarcate the lung segment perfused by an anomalous systemic artery.Case presentationA 15-year-old boy was diagnosed with an anomalous artery originating from the celiac artery and supplying the right dorsobasal lung segment (S10). Via three-port video-assisted thoracoscopic surgery, the anomalous artery was ligated and processed with an auto-stapler. Indocyanine green was injected intravenously to identify the tissue perfused by the anomalous artery, and the lung was resected.ConclusionsWith anomalous systemic arterial supply to normal basal lung segments, indocyanine green can be particularly helpful in identifying the boundaries of the perfused area. Then, the affected tissue can be resected by thoracoscopic surgery.

Massive hemoptysis treated with embolization of an ectopic bronchial artery arising from the right thyrocervical trunk: a case report

BackgroundEctopic bronchial artery and non-bronchial systemic arteries may be the culprit vessels of hemoptysis. The main cause of clinical failure of bronchial artery embolization is incomplete embolization caused by the misidentification of the culprit arteries by conventional angiography. Multidetector computed tomography angiography is useful for visualizing the culprit arteries.Case presentationAn 82-year-old man was admitted with hemoptysis. Preprocedural multidetector computed tomography angiography revealed an ectopic bronchial artery branching from the right thyrocervical trunk. Superselective embolization of the ectopic bronchial artery was performed using gelatin sponge particles and metallic coils. Hemoptysis was controlled by this procedure without any associated complications.ConclusionsEctopic bronchial arteries originating from the thyrocervical trunk are rare. Preprocedural multidetector computed tomography angiography is useful for visualizing the culprit arteries of hemoptysis, especially if a patient has an ectopic bronchial artery or an ectopic non-bronchial systemic artery.

Ventilation heterogeneity imaged by multibreath wash-ins of hyperpolarized 3 He and 129 Xe in healthy rabbits.

Multibreath imaging to estimate regional gas mixing efficiency is superior to intensity-based single-breath ventilation markers, as it is capable of revealing minute but essential measures of ventilation heterogeneity which may be sensitive to subclinical alterations in the early stages of both obstructive and restrictive respiratory disorders. Large-scale convective stratification of ventilation in central-to-peripheral directions is the dominant feature of observed ventilation heterogeneity when imaging a heavy/less diffusive xenon gas mixture; smaller-scale patchiness, probably originating from asymmetric lung function at bronchial airway branching due to the interaction of convective and diffusive flows, is the dominant feature when imaging a lighter/more diffusive helium gas mixture. Since detecting low regional ventilation is crucial for characterizing diseased lungs, our results suggest that dilution with natural abundance helium and imaging at higher lung volumes seem advisable when imaging with hyperpolarized 129 Xe; this will allow the imaging gas to reach slow-filling and/or non-dependent lung regions, which might otherwise be impossible to distinguish from total ventilation shunt regions. The ability to differentiate these regions from those of total shunt is worse with typical single-breath imaging techniques. The mixing of freshly inhaled gas with gas already present in the lung can be directly assessed with heretofore unachievable precision via magnetic resonance imaging of signal build-up resulting from multiple wash-ins of a hyperpolarized (HP) gas. Here, we used normoxic HP 3 He and 129 Xe mixtures to study regional ventilation at different spatial scales in five healthy mechanically ventilated supine rabbits at two different inspired volumes. To decouple the respective effects of density and diffusion rates on ventilation heterogeneity, two additional studies were performed: one in which 3 He was diluted with an equal fraction of natural abundance xenon, and one in which 129 Xe was diluted with an equal fraction of 4 He. We observed systematic differences in the spatial scale of specific ventilation heterogeneity between HP 3 He and 129 Xe. We found that large-scale, central-to-peripheral convective ventilation inhomogeneity is the dominant cause of observed heterogeneity when breathing a normoxic xenon gas mixture. In contrast, small-scale ventilation heterogeneity in the form of patchiness, probably originating from asymmetric lung function at bronchial airway branching due to interactions between convective and diffusive flows, is the dominant feature when breathing a normoxic helium gas mixture, for which the critical zone occurs more proximally and at an imageable spatial scale. We also showed that the existence of particular underventilated non-dependent lung regions when breathing a heavy gas mixture is the result of the density of that mixture - rather than, for example, its diffusion rate or viscosity. Finally, we showed that gravity-dependent ventilation heterogeneity becomes substantially more uniform at higher inspired volumes for xenon gas mixtures compared to helium mixtures.

DIFFERENTIAL DIAGNOSTICS OF CHRONIC BRONCHITIS IN CHILDREN

Currently, the diagnosis of chronic bronchitis as an independent nosological form in children is being improved. This direction provides for the differentiation of chronic bronchitis from other bronchopulmonary diseases occurring with bronchitis syndrome. It is known that chronic bronchitis is a constant companion of bronchiectasis, primary ciliary dyskinesia and its main form - Kartagener's syndrome, and is also one of the manifestations of cystic fibrosis. The viciousness of the development of the bronchopulmonary system (aplasia, hypoplasia of the lungs, Mounier-Kuhn syndrome, Williams-Campbell syndrome, polycystic lung disease, bronchial branching anomalies), as a rule, predisposes to the formation of chronic bronchitis.

Feasibility of manual bronchial branch reading technique in navigating conventional rEBUS bronchoscopy in the evaluation of peripheral pulmonary lesion.

Although radial endobronchial ultrasound (rEBUS) is an important verification tool in guided bronchoscopy, a navigational route was not provided. Manual airway mapping allows the bronchoscopist to translate the bronchial branching in computed tomography (CT) into a comparable bronchoscopic road map. We aimed to explore the feasibility of this technique in navigating conventional rEBUS bronchoscopy in the localisation of peripheral pulmonary lesion by determining navigation success and diagnostic yield. Retrospective review of consecutive rEBUS bronchoscopy performed with a 6.2 mm conventional bronchoscope navigated via manual bronchial branch reading technique over 18 months. Ninety-eight target lesions were included. Median lesion size was 2.67 cm (IQR 2.22-3.38) with 96.9% demonstrating positive CT bronchus sign. Majority (86.7%) of lesions were situated in between the third and fifth airway generations. Procedure was performed with endotracheal intubation in 43.9% and fluoroscopy in 72.4%. 98.9% of lesions were successfully navigated and verified by rEBUS following the pre-planned airway road map. Bidirectional guiding device was employed in 29.6% of cases. Clinical diagnosis was secured in 88.8% of cases, majority of which were malignant disease. The discrepancy between navigation success and diagnostic yield was 10.1%. Target PPL located within five airway generations was associated with better diagnostic yield (95.1% vs. 58.8%, P<0.001). There was 1 (1.0%) pneumothorax in our cohort. Manual bronchial branch reading technique in combination with conventional rEBUS is feasible in localisation of PPL, especially for lesions located within the first five airway generations.

Characterisation of computed tomography angiography findings in paediatric patients with heterotaxy.

Heterotaxy refers to the abnormal arrangement of organs across the left-right axis and is typically associated with complex cardiovascular malformations. To characterise the range of cardiac and extracardiac CT angiography findings in children with heterotaxy using the latest nomenclature consensus and to compare the different types of isomerism. We retrospectively analysed the data of 64 consecutive paediatric patients referred to our tertiary paediatric cardiovascular centre who underwent CT angiography for the evaluation of known or suspected heterotaxy within a 52-month period. Right atrial isomerism was identified in 44 (69%) children, while left atrial isomerism was identified in 18 (28%) children. Atrial appendage anatomy and situs could not be determined in 2 children (3%). Associated heart defects included complete atrioventricular canal (CAVC) in 51 (80%) children, total anomalous pulmonary venous return in 43 (67%) and pulmonary atresia in 23 (36%). The bronchial branching pattern corresponded to atrial appendage morphology in all children except in the two in whom atrial appendage morphology could not be defined. In children with right atrial isomerism, the most common associated abnormalities were CAVC (n=41, 93%) and asplenia (n=34, 77%), while in those with left atrial isomerism, the most common associated abnormalities were polysplenia (n=17, 94%) and an interrupted inferior vena cava with azygos continuation (n=15, 83%). CT angiography provides useful cardiovascular and extracardiac data on heterotaxy, which frequently involves a pattern of side-related findings but has great anatomical variability.

Accessory Left Lung Fissure with Rare Branching Pattern of Bronchial Tree

Pulmonary fissures separate bronchopulmonary segments and delineate lungs into lobes Anatomical variation of these fissures lie on a continuum from completely fused lobes to accessory fissures in about 17.5% of right and 2% of left lungs. Hilar variations in the bronchial tree and vasculature can also be seen in lobar abnormalities.A routine dissection of an 83‐year‐old male cadaver showed an accessory fissure in the left lung. The hilum of the lung was further dissected for visualization of the bronchial tree and vasculature to explore mediastinal relationships and bronchopulmonary segments. Photographs were taken after dissection. The completeness of the accessory fissure and position of the pulmonary artery were classified using the Craig and Walker Scale.An accessory horizontal fissure forming a complete visceral cleft divided the superior and inferior lingular bronchopulmonary segments of the left lung. However, the fissure did not extend into the hilum at its base and may be classified as a Grade 2 fissure, a “complete visceral cleft but parenchymal fusion at the base.” While the pulmonary artery was positioned normally with reference to oblique fissure, the main and superior lobar bronchus showed variant branching pattern. The left main (primary) bronchus gave rise to the superior and inferior lobar (secondary) bronchi prior to entering the hilum. A normal division of the superior lobar bronchus was observed anterior to the pulmonary artery. The lingular branch of the superior lobar bronchus trifurcated into a rare accessory posterior segmental bronchus in addition to the normal superior and inferior segmental (tertiary) bronchi. The superior and inferior lingular bronchopulmonary segments separated by the accessory fissure were supplied by superior and inferior segmental bronchi, respectively, while the rare accessory posterior segmental bronchus supplied the base of the accessory fissure. The inferior lobar (secondary) bronchus showed normal division and was situated posterior to the pulmonary artery in the hilum. The mediastinal relationships showed the left pulmonary artery posterosuperior instead of anterosuperior to the main bronchus. No cardiac abnormalities were observed.Fewer structural abnormalities have been reported in the left lung in comparison to the right. Bilateral isomerism of the lungs is often associated with heterotaxia, wherein other structures in the chest and abdomen are also altered. In this case, while the left lung had two fissures similar to a right lung, there is no evidence of heterotaxia, suggesting that the abnormality arose from lung bud branching unilaterally during pulmonary development. Knowledge of possible accessory fissures and variant segmental bronchial branching is of clinical importance in understanding the pathological conditions, particularly for radiologists conducting imaging studies and pulmonologists and surgeons conducting bronchoscopies, biopsies and balloon bronchoplasties to place airway stents and lobectomies.Support or Funding InformationSupport from Touro College of Osteopathic Medicine.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Multidetector Computed Tomographic Anatomy of the Lungs in the Loggerhead Sea Turtle (Caretta caretta)

Multidetector computed tomographic (CT) anatomy was used to evaluate the lungs of 10 loggerhead sea turtle (Caretta caretta) without pulmonary disease, in order to provide a baseline of turtle lung anatomy by CT imaging. In all patients, in this retrospective anatomic study, the CT datasets were carefully evaluated for assessment of the bronchial tree morphology and branching pattern, of the arborization pattern of pulmonary arteries and veins and of the bronchoarterial-bronchovenous diameter ratios. Imaging anatomy was compared with previous published data based on dissection and microscopic anatomy. With the increasing availability of advanced imaging tools for wildlife animal patients, a detailed CT anatomy background is required to decipher correctly the pathologic respiratory conditions of sea turtles. Anat Rec, 302:1658-1665, 2019. © 2018 American Association for Anatomy.

Variations of right bronchial tree: a study with multi-detector CT.

The aim was to display variations of right bronchial tree. The bronchial tree images of 238 patients were reconstructed using the postprocessing technique of CT. We revealed four cases rare bronchial branching patterns of right superior lobe. 1 case was referred to as tracheal bronchus. In 1 case, B1 was located in the place of the right superior lobar bronchus and B2 + 3 arose from the right merge of the IB. In 1 case, the right superior lobar bronchus has only two divisions for B1 and B3, and the bronchus B2 arose from the right merge of the IB. In 1 case, B1 branched into four bronchi. We revealed 15 cases of rare bronchial branching patterns of right inferior lobe. In nine cases, the basal trunk bronchus bifurcated into B7 + 8 and B9 + l0. In three cases, B8 branched from the basal trunk bronchus before B7. In two cases, basal trunk bronchus bifurcated into B7 + 8 + 9 and B10. In 1 case, the basal trunk bronchus bifurcated into the common stem of B7 + 10 and B8 + 9. Variations of right bronchial tree were displayed in the present study. This information may have important implications for diagnosis of symptomatic patients and performing certain procedures, including bronchoscopy, endotracheal intubation, and lung resection.

Regulatory role of Shh signaling pathway in lung development in fetal mice

To investigate the regulatory role of classical Shh signaling pathway in the development of the epithelium and mesenchyme (bronchial cartilage and smooth muscles) during lung development in fetal mice. Immunohistochemical technique was used to detect the expression of Shh signaling pathway receptor Smo and Pdgfr-α in murine fetal lungs to explore the spatial and temporal characteristics of their expression. Based on the interstitial specificity of Pdgfr-α expression, we constructed a Pdgfr-α-cre to establish a E12.5 - E16.5 transgenic mice with specific knockout of the key Shh signaling molecule Smo in the pulmonary interstitium with tamoxifen induction. Immunofluorescence technique was used to observe the epithelium and mesenchyme (bronchial cartilage and smooth muscle) during fetal lung development in the transgenic mice to assess the role of Shh signaling pathway in the epithelial-to-mesenchymal (EMT) transition during the lung development. Smo was highly expressed in the epithelial and stromal lung tissues in the pseudoglandular stage and was gradually lowered over time with its distribution mainly in the interstitial tissues. Pdgfr-α was enriched in the distal lung epithelial and mesenchy tissues in early embryonic lungs and gradually migrated to the proximal stroma until becoming concentrated around the main bronchial proximal stroma. We successfully specific established mouse models of specific mesenchymal Smo knockout. Compared with the control group, the transgenic mice during E12.5-E16.5 showed significantly reduced lung the volume and bronchial branching with also decreased expression of the proximal epithelial P63 (P<0.05). The transgenic mice exhibited alterations in the expression of α-smooth muscle actin with delayed bronchial cartilage development and decreased expression of mucoprotein. The temporospatial specific expression of Shh signaling pathway plays an important role in developmental regulation of mouse embryonic lung epithelium and mesenchyme (bronchial cartilage and smooth muscle).

A cadaveric study on accessory lobes of lungs and their bronchial branching pattern

Background: An accessory lobe is a part of lung tissue separated off by an accessory fissure. It develops due to occasional monopodial branching of the stem bronchi. Different accessory lobes may be encountered in the human lungs e.g., azygos lobe, dorsal lobe, cardiac lobe and tracheal lobe. An accessory lobe may be confused with a lung abscess or bulla in x-ray and CT-scan, and its variable bronchial supply may cause difficulty during bronchoscopy. Hence, the present work has been carried out to study the accessory lobes and their bronchial branching pattern in human lungs. Materials and Methods: 92 adult human lungs (46 right and 46 left) were collected from the Department of Anatomy and Department of Forensic and State Medicine, Gauhati Medical College and Hospital, Guwahati, Assam and preserved in 10% formalin. The lungs were, then, examined for accessory lobes and their bronchial supply was noted following dissection from the hilum. Results: In the present study, the azygos lobes were present in 2.17% of cases and dorsal lobe was present in 1.08% of cases, all of which belonged to the right side. The azygos lobes were supplied by the apical segmental bronchus of the right superior lobe and dorsal lobe was supplied by the apical basal segmental bronchus and posterior basal segmental bronchus of the right inferior lobe. Conclusion: A detailed knowledge of the accessory lobes and their bronchial supply is important for correct radiological diagnosis and bronchoscopic examination of lungs.

Morphological and functional properties of the conducting human airways investigated by in vivo computed tomography and in vitro MRI.

The accurate representation of the human airway anatomy is crucial for understanding and modeling the structure-function relationship in both healthy and diseased lungs. The present knowledge in this area is based on morphometric studies of excised lung casts, partially complemented by in vivo studies in which computed tomography (CT) was used on a small number of subjects. In the present study, we analyzed CT scans of a cohort of healthy subjects and obtained comprehensive morphometric information down to the seventh generation of bronchial branching, including airway diameter, length, branching angle, and rotation angle. Although some of the geometric parameters (such as the child-to-parent branch diameter ratio) are found to be in line with accepted values, for others (such as the branch length-to-diameter ratio) our findings challenge the common assumptions. We also evaluated several metrics of self-similarity, including the fractal dimension of the airway tree. Additionally, we used phase-contrast magnetic resonance imaging (MRI) to obtain the volumetric flow field in the three-dimensional-printed airway model of one of the subjects during steady inhalation. This is used to relate structural and functional parameters and, in particular, to close the power-law relationship between branch flow rate and diameter. The diameter exponent is found to be significantly lower than in the usually assumed Poiseuille regime, which we attribute to the strong secondary (i.e., transverse) velocity component. The strength of the secondary velocity with respect to the axial component exceeds the levels found in idealized airway models and persists within the first seven generations. NEW & NOTEWORTHY We performed a comprehensive computed tomography-based study of the conductive airway morphology in normal human subjects, including branch diameter, length, and mutual angles. We found significant departure from classic homothetic relationships. We also carried out MRI measurements of the three-dimensional inspiratory flow in an anatomy-based model and directly assessed structure-function relationships that have so far been assumed. We found that strong secondary flows (i.e., transverse velocity components) persist through the first seven generations of bronchial branching.

Bilateral Accessory Lung Fissures with a Variant Left Bronchial Tree

Accessory lung fissures are commonly noted, while bronchial branching abnormalities are less frequently found and are proposed to occur in 0.1–2% of the general population. Multiple accessory fissures, variant normal fissures of both lungs, and an altered left bronchial tree are unique to this case and is being reported due to its clinical significance. During a routine dissection of the thoracic cavity of an 85‐year‐old female cadaver, abnormal fissures were noted on both the right and left lungs, which were photographed. The bronchial branching was further dissected by tracing the bronchus from the hilum to the lung tissue. The right lung had a normal oblique fissure, while the horizontal fissure was shallow and incomplete. The left lung had a normal oblique fissure, and a minor fissure was noted running along the junction of the anterior (S3) and superior lingular (S4) bronchopulmonary segments. Accessory fissures were noted on both right and left lungs. The left bronchus was short and displayed an early division into upper and lower divisions. The dissection of the bronchial tree of the left lung showed trifurcation of the upper division into apicoposterior, anterior, and lingular bronchi. The lower division was normal. The right bronchial tree showed normal division. Examination of the heart revealed an atrial septal defect. The other thoracic and abdominal structures were examined and appeared normal. Knowledge of accessory fissures in the lung have importance in the clinical diagnosis of lobar pneumonia versus atelectasis with imaging and during resection of bronchopulmonary segments. Understanding this bronchial variation and anomalies have implications in diagnosis and endobronchial treatment, including airway stenting, bronchoscopy, endoscopy biopsy, and laser therapy.Support or Funding InformationTouro College of Osteopathic Medicine, Department of Anatomy

Bridging bronchus, type six, as a new rare case of a bronchial anomaly.

In 1976, Gonzales-Crussi et al. (Am. J. Dis. Child. 130:1015–18, 1976) introduced the first case of bridging bronchus as a rare bronchial branching anomaly; since then, only 14 worldwide cases was described. We suggest our case might be number 15 and could be the first case of type six of this bronchial anomaly. We present a case of a 10-month-old infant with bridging bronchus, congenital tracheal stenosis, and double outlet right ventricle who underwent major laparoscopic surgery for repair of gastrointestinal anomalies to raise awareness of this rare underdiagnosed congenital anomaly and a thorough discussion of the tracheobronchial anomalies and its clinical implications.