Bronchial anatomy of left lung: a study of multi-detector row CT

Identification of anatomical types of segmental bronchi in left superior and lingular lobes using multi-slice CT

PURPOSE

The objectives of this study were to evaluate various branching patterns of segmental bronchi in the left superior and lingular lobes and to survey the anatomical diversity and sex-related differences of these branches in a large sample of the study population.

MATERIALS AND METHODS

Overall, 10,000 participants (5428 males, and 4572 females, mean age 50 ± 13.5 years [SD] years; age range: 3-91 years) who underwent multi-slice CT (MSCT) scans between September 2019 and December 2021 were retrospectively included. Using the syngo.via post-processing workstation, the data were applied to generate three-dimensional (3D) and virtual bronchoscopy (VB) simulations of a bronchial tree. The reconstructed images were then interpreted to identify and categorize distinct bronchial patterns in the left superior and lingular lobes. Cross-tabulation analysis and the Pearson Chi-square (χ2) test were used to calculate the constituent ratios of bronchial branch types and determine their significance between male and female groups.

RESULTS

Our results revealed mainly four distinct types for the left superior lobe (LSL) bronchial tree, i.e., (B1 + 2, B3, 76.13%); (B1 + 2 + 3, 17.32%); (B1 + 3, B2, 5.74%); (B1a + B3, B1b + B2, 0.81%) and two types for the left lingular lobe (LLL) bronchial tree, i.e., (B4, B5, 91.05%); (B4, B5, B*, 8.95%). There were no significant sex-related differences in the proportion of bronchial branches in LLL (P > 0.05). However, sex-related differences were significant in the proportion of bronchial branches in LSL (P < 0.05).

CONCLUSION

The current study has validated the presence of segmental bronchial variations in the left superior and lingular lobes. These findings may have a crucial effect on the diagnosis of symptomatic patients, as well as in carrying out procedures such as lung resections, endotracheal intubation, and bronchoscopies.

Identification of anatomical types of segmental bronchi in right middle lobe using multi-slice CT

PURPOSE

The objectives of this study were to evaluate the various branching patterns of segmental bronchi in the right middle lobe (RML) and to survey the anatomical diversity and sex-related differences of these branches in a large sample of the study population.

MATERIALS AND METHODS

In this retrospective board-approved study with informed consent, 10,000 participants (5428 males and 4,572 females, mean age 50 ± 13.5 years [SD]; age range: 3-91 years) who underwent multi-slice CT (MSCT) scans from September 2019 to December 2021 were retrospectively included. The data were applied to generate three-dimensional (3D) and virtual bronchoscopy (VB) simulations of a bronchial tree using the syngo.via post-processing workstation. The reconstructed images were then interpreted to locate and classify distinct bronchial patterns in the RML. Cross-tabulation analysis and the Pearson chi-square test were used to calculate the constituent ratios of bronchial branch types and determine their significance between male and female groups.

RESULTS

Our results revealed that the segmental bronchial ramifications of the RML were classified into two types mainly, i.e., bifurcation (B4, B5, 91.42%) and trifurcation (B4, B5, B*, 8.58%). There were no significant sex-related differences in the proportion of bronchial branches in the RML (P > 0.05).

CONCLUSION

The current study has confirmed the presence of segmental bronchial variations in the RML lobe using 3D reconstruction and virtual bronchoscopy. These findings may have significant implications for the diagnosis of symptomatic patients and for carrying out specific procedures like bronchoscopy, endotracheal intubation, and lung resection.

Hilar Abnormality in the Left Lung: Left Pulmonary Artery Posterior to the Left Mainstem Bronchus

The thoracic cavity contains vital cardiovascular and pulmonary structures. Few congenital anatomical variations in the bronchial tree and pulmonary vasculature have been reported. Understanding such variants is crucial during surgical procedures that involve the thorax. During routine dissection of an 89-year-old male cadaver as part of a first-year anatomy course, an anomaly of the bronchial tree was discovered. The left lung hilum was notable for the pulmonary artery being posterior to the mainstem bronchus. The case report describes normal lung development and anatomy and the significance of this novel variation in which has not been previously described in the literature.

Pulmonary vessels and bronchus anatomy of the left upper lobe

PURPOSES

The bronchopulmonary vascular bifurcation patterns in the upper lobe of the left lung are diverse. Therefore, it is important for general thoracic surgeons to understand the detailed anatomy of the pulmonary segments when performing thoracoscopic anatomical pulmonary resection. This study aimed to analyze the bronchovascular patterns of the left upper lobe and summarize the anatomical information associated with pulmonary anatomical pulmonary resection.

METHODS

We reviewed the anatomical patterns of pulmonary vessels and the left lung bronchus of 539 patients using computed tomography imaging data including those obtained using three-dimensional computed tomography. We herein report the anatomic structure in the left upper lobe.

RESULTS

Regarding the superior division bronchi, a pattern of trifurcation into B¹⁺², B³, lingular division bronchus was observed in nine patients (1.7%). A pattern of proximal bifurcation of B⁴ was found in eight patients (1.5%). Regarding the lingular veins (LV), patterns of LV drainage into the left lower pulmonary vein were observed in 22 patients (4.1%). Regarding the pulmonary artery, mediastinal lingular arteries (MLA) were found in 161 patients (29.9%).

CONCLUSION

The bifurcation patterns of the bronchovascular region in the upper lobe of the left lung were clarified. These results should be carefully noted when performing anatomical pulmonary resection.

Anatomy of the left subsuperior segment for segmentectomy

PURPOSE

The subsuperior segmental bronchi (B*) forms the subsuperior segment (S*) between the superior (S⁶) and basal segment (S⁷, S⁸, S⁹, S¹⁰) of the lung. However, the anatomical planes of S* remains undefined. The present study clarified the anatomical features of S*.

METHODS

We reviewed the anatomical patterns of pulmonary vessels and the left lung bronchus in 539 patients using three-dimensional computed tomography. We report the anatomic structure in S*.

RESULTS

A total of 537 patients were analyzed. B* was observed in 129 (24.0%) patients. The intersegmental vein between S⁶ and S* was complete in all cases. The absence of intersegmental veins of S* was observed in 77 (14.3%) patients, reaching 59.7% of B* cases. Twenty-two (4.1%) cases of B* diverged from the trunk of the basal bronchus, and about half of the B* branched to the dorsolateral (n = 77, 14.3%) or dorsal (n = 2, 0.37%) direction.

CONCLUSION

Our study revealed the branching patterns of B* and anatomical intersegmental veins of S*. Our results provide useful information regarding anatomical segmentectomy including or adjusting to the left S*.

Demarcation of arteriopulmonary segments: a novel and effective method for the identification of pulmonary segments

Objective

Each pulmonary segment is an anatomical and functional unit. However, it is fundamentally difficult to precisely distinguish every pulmonary segment using the conventional pulmonary intersegmental planes from computed tomography images. Building arteriopulmonary segments is likely to be an effective way to identify pulmonary segments.

Methods

The thoracic computed tomography images of 40 patients were collected. The anatomic structures of interest were extracted in the transverse, sagittal, and coronal planes using the semi-automated segmentation tools provided by Amira software. The intrapulmonary vessels were subsequently segmented and reconstructed. The distributions of the pulmonary arteries, veins, and bronchi were observed. In patients with pulmonary masses, the mass was also reconstructed.

Results

The three-dimensional reconstructed images showed the branches of the pulmonary artery ramified up to their eighth order covering the entire lung as well as evident intersegmental gaps without pulmonary arteries. The segmental artery was closely accompanied by the segmental bronchi in 486 pulmonary segments (90% of total number of segments). The size and spatial location of the pulmonary mass within a pulmonary segment were also clearly visible.

Conclusions

Demarcation of arteriopulmonary segments can be used to precisely distinguish every pulmonary segment and provide its detailed anatomical structure before pulmonary segmentectomy.

Pulmonary vessels and bronchial anatomy of the left lower lobe

PURPOSE

To identify and clarify the comprehensive anatomic patterns in the left lower lobe (LLL).

METHODS

Using computed tomography (CT) imaging data, including that obtained using three-dimensional CT, we reviewed the anatomic patterns of the pulmonary vessels and bronchi in the left lungs of 539 patients, focusing on the LLL.

RESULTS

The two-stem type in A⁶ was observed in 131 (24.7%) patients and the three-stem type in A⁶ was observed in 11 (2.1%) patients. The independent two-stem type in B⁶ was observed in four (0.75%) patients. The B⁷ with independent branching from the basal bronchi was observed in 42 (7.9%) patients. B* was observed in 129 (24.0%) patients and B* was accompanied by A* in all patients. An extrapericardial common trunk of the left pulmonary veins was identified in five patients (0.93%).

CONCLUSION

We identified various bronchovascular patterns in the LLL of a large number of patients. Our results provide useful information for anatomic pulmonary resection, especially segmentectomy.

Atypical bronchus in the right lower lobe: Computed tomography-based analysis

INTRODUCTION

The aim of this study was to define the subsuperior bronchus (B*) and reestablish the bronchial anatomy of the right lower lobe (RLL) by assessment of atypical bronchi.

MATERIALS AND METHODS

Chest computed tomography (CT) scans of 500 consecutive patients were retrospectively evaluated. All CT scans were acquired with 64-slice scanners. Atypical bronchi in the RLL were classified on the basis of running direction and shape: lateral (Lat), posterolateral (PL), posterior (Post), Lat + PL, and PL + Post. We classified an atypical bronchus in the basal segmental bronchus (BSB) stem running posteriorly or posterolaterally as B* and a para-lateral bronchus running laterally as Para-B8. The B* posts running posteriorly were named P1, and those running medially P2.

RESULTS

Atypical BSB bronchi Lat, PL, and Post arose from B8, B9, and B10, respectively. All Lat + PL bronchi arose from B8 or B9, and all PL + Post from B9 or B10. When an atypical bronchus arose from one of the BSB pair, none arose from the other. Atypical bronchi forming B* and Para-B8 arose from the stem spreading the connatural BSBs. The P2 post coexisted with another atypical stem bronchus originating from B8, 9, 10, or higher.

CONCLUSIONS

The first subsegmental bronchi of B8, B9, and B10 are Lat, PL, and Post, respectively. Lat + PL and PL + Post bronchi at the BSB level could result from fusion of an atypical bronchus during downward migration. The stem B* and Para-B8 could result from arrested downward migration of atypical bronchi. This information is useful for RLL segmentectomy.

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

PURPOSE

The aim was to display variations of right bronchial tree.

METHODS

The bronchial tree images of 238 patients were reconstructed using the postprocessing technique of CT.

RESULTS

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.

CONCLUSIONS

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.

Automatic construction of subject-specific human airway geometry including trifurcations based on a CT-segmented airway skeleton and surface

We propose a method to construct three-dimensional airway geometric models based on airway skeletons, or centerlines (CLs). Given a CT-segmented airway skeleton and surface, the proposed CL-based method automatically constructs subject-specific models that contain anatomical information regarding branches, include bifurcations and trifurcations, and extend from the trachea to terminal bronchioles. The resulting model can be anatomically realistic with the assistance of an image-based surface; alternatively a model with an idealized skeleton and/or branch diameters is also possible. This method systematically identifies and classifies trifurcations to successfully construct the models, which also provides the number and type of trifurcations for the analysis of the airways from an anatomical point of view. We applied this method to 16 normal and 16 severe asthmatic subjects using their computed tomography images. The average distance between the surface of the model and the image-based surface was 11 % of the average voxel size of the image. The four most frequent locations of trifurcations were the left upper division bronchus, left lower lobar bronchus, right upper lobar bronchus, and right intermediate bronchus. The proposed method automatically constructed accurate subject-specific three-dimensional airway geometric models that contain anatomical information regarding branches using airway skeleton, diameters, and image-based surface geometry. The proposed method can construct (i) geometry automatically for population-based studies, (ii) trifurcations to retain the original airway topology, (iii) geometry that can be used for automatic generation of computational fluid dynamics meshes, and (iv) geometry based only on a skeleton and diameters for idealized branches.

CT virtual endoscopy for analyzing variations in the hepatic portal vein

PURPOSE

To evaluate the value of CT virtual endoscopy (CTVE) for accurately distinguishing varying types of portal veins (PVs).

MATERIALS AND METHODS

From 526 consecutive patients whose hepatic portal vein was well visualized, patients who were considered to have trifurcation of the main portal vein (MPV) or right portal vein (RPV) on volume rendering (VR) and maximum intensity projection (MIP) imaging were chosen for the analysis. Two radiologists evaluated the PV anatomy of these patients and re-classified the types of PV variation using the CTVE technique. The Wilcoxon rank sum test was used to calculate differences in age between males and females.

RESULTS

Thirty-two patients (20 males, 12 females; age range 21-68 years; mean age 43 years) were considered to have trifurcation of the MPV (15) or RPV (17) on VR and MIP imaging. Fifteen patients in total had a trifurcation confirmed by CTVE (6 patients were proven to have an MPV trifurcation by CTVE, and 9 were confirmed to have a RPV trifurcation).

CONCLUSIONS

CTVE can differentiate PV variations that cannot be identified accurately on MIP and VR.

Three-dimensional reconstruction of thoracic structures: based on Chinese Visible Human

We managed to establish three-dimensional digitized visible model of human thoracic structures and to provide morphological data for imaging diagnosis and thoracic and cardiovascular surgery. With Photoshop software, the contour line of lungs and mediastinal structures including heart, aorta and its ramus, azygos vein, superior vena cava, inferior vena cava, thymus, esophagus, diaphragm, phrenic nerve, vagus nerve, sympathetic trunk, thoracic vertebrae, sternum, thoracic duct, and so forth were segmented from the Chinese Visible Human (CVH)-1 data set. The contour data set of segmented thoracic structures was imported to Amira software and 3D thorax models were reconstructed via surface rendering and volume rendering. With Amira software, surface rendering reconstructed model of thoracic organs and its volume rendering reconstructed model were 3D reconstructed and can be displayed together clearly and accurately. It provides a learning tool of interpreting human thoracic anatomy and virtual thoracic and cardiovascular surgery for medical students and junior surgeons.

Usefulness of computed tomography virtual bronchoscopy in the evaluation of bronchi divisions

Background:

Since introduction of multislice CT scanners into clinical practice, virtual brochoscopy has gained a lot of quality and diagnostic potential. Nevertheless it does not have established place in diagnostics of tracheal and bronchi disorders and its potential has not been examined enough. Nowadays a majority of bronchial tree variants and lesions are revealed by bronchofiberoscopy, which is an objective and a relatively safe method, but has side effects, especially in higher-risk subjects. Therefore noninvasive techniques enabling evaluation of airways should be consistently developed and updated.

Material/Methods:

Material consisted of 100 adults (45 female, 55 male) aged between 18 and 65 years (mean 40 years, median 40.5 years, SD 14.02), who underwent chest CT examination by means of a 16-slice scanner. Every patient had normal appearance of chest organs, with the exception of minor abnormalities that did not alter airways route.

Divisions of bronchial tree to segmental level were evaluated and assigned to particular types by means of virtual bronchoscopy projection. In case of difficulties MPR or MinIP projection was used.

Results:

The frequency of lobar bronchi divisions other than the typical ones was in: right upper lobar bronchi 45%, left 55%; middle lobar bronchi 21%, lingula 26%; right lower lobar bronchi 28%, left 29%. Subsuperior bronchus or bronchi were found on the right side in 44% and on the left side in 37%. No dependency between types of bronchial divisions on different levels was found.

A role for mesenchyme dynamics in mouse lung branching morphogenesis

Mammalian airways are highly ramified tree-like structures that develop by the repetitive branching of the lung epithelium into the surrounding mesenchyme through reciprocal interactions. Based on a morphometric analysis of the epithelial tree, it has been recently proposed that the complete branching scheme is specified early in each lineage by a programme using elementary patterning routines at specific sites and times in the developing lung. However, the coupled dynamics of both the epithelium and mesenchyme have been overlooked in this process. Using a qualitative and quantitative in vivo morphometric analysis of the E11.25 to E13.5 mouse whole right cranial lobe structure, we show that beyond the first generations, the branching stereotypy relaxes and both spatial and temporal variations are common. The branching pattern and branching rate are sensitive to the dynamic changes of the mesoderm shape that is in turn mainly dependent upon the volume and shape of the surrounding intrathoracic organs. Spatial and temporal variations of the tree architecture are related to local and subtle modifications of the mesoderm growth. Remarkably, buds never meet after suffering branching variations and continue to homogenously fill the opening spaces in the mesenchyme. Moreover despite inter-specimen variations, the growth of the epithelial tree and the mesenchyme remains highly correlated over time at the whole lobe level, implying a long-range regulation of the lung lobe morphogenesis. Together, these findings indicate that the lung epithelial tree is likely to adapt in real time to fill the available space in the mesenchyme, rather than being rigidly specified and predefined by a global programme. Our results strongly support the idea that a comprehensive understanding of lung branching mechanisms cannot be inferred from the branching pattern or behavior alone. Rather it needs to be elaborated upon with the reconsideration of mesenchyme-epithelium coupled growth and lung tissues mechanics.

Quick dissection of the segmental bronchi

Knowledge of the three-dimensional anatomy of the bronchopulmonary segments is essential for respiratory medicine. This report describes a quick guide for dissecting the segmental bronchi in formaldehyde-fixed human material. All segmental bronchi are easy to dissect, and thus, this exercise will help medical students to better understand the bronchopulmonary segments.