VARIATIONS IN THE BRONCHOVASCULAR PATTERNS OF THE LEFT LOWER LOBE OF FIFTY LUNGS

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.

Prevalence and anatomical characteristics of subsuperior segment in lung lower lobe

OBJECTIVE

The subsuperior segment is an atypical pulmonary segment of the lung lower lobe. With the increased application of segmentectomy, it has received increased attention from thoracic surgeons. Studies of the subsuperior segment are scarce and mostly on the basis of small-sample autopsy studies, whose described characteristics are inconsistent with intraoperative observations. Our objective was to accurately define the subsuperior segment and elucidate its prevalence and anatomical characteristics in detail.

METHODS

A total of 2194 chest computed tomography images were obtained using separate random sampling on the basis of the amount of data available to each of the 6 thoracic surgery institutions in different provinces covering various regions of China. All of the images were reconstructed in 3 dimensions. Subsuperior segments were screened according to their new definition and statistically analyzed for their prevalence and anatomical characteristics.

RESULTS

The prevalence of subsuperior segments was 32.04%, with 413 on the right (18.79%); the value was higher than that on the left (347; 15.81%). The average volume of the subsuperior segment was 52.81 ± 21.96 cm3. Only 1 bronchus was detected in the unilateral subsuperior segment, with an average diameter of 2.53 ± 0.61 mm. Only 1 pulmonary artery was observed in most of the subsuperior segments (89.34%), but 81 cases (10.66%) had 2 in our study. One intersegmental vein of the subsuperior segment was the most common situation on both sides.

CONCLUSIONS

Using a multicenter large-sample study, we calculated a 32.04% prevalence and systematically detailed the anatomical characteristics of the subsuperior segment in the lung lower lobe, corrected previous reports, and supplemented pulmonary anatomical studies.

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.

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

Familiarity with prevailing pattern and variations in the bronchial tree is not only essential for the anatomist to explain bronchial variation in bronchial specimens, but also useful for guiding bronchoscopy and instructing pulmonary segmental resection. The purpose of this study was designed to demonstrate various branching patterns of left lung with 3D images, with special attention given to identify the major types at transverse thin-section CT. Two hundred and sixteen patients with routine thorax scans were enrolled. The images of bronchial tree, virtual bronchoscopy were reconstructed using post-processing technique of multi-detector row CT. We attempted to classify the segmental bronchi by interpreting the post-processing images, and identified them in transverse thin-section CT. Our results showed that the segmental bronchial ramifications of the left superior lobe were classified into three types mainly, i.e., common stem of apical and posterior segmental bronchi (64%, 138/216); trifurcation (23%, 50/216); common stem of apical and anterior segmental bronchi (10%, 22/216), and they could be identified at two typical sections of transverse thin-section CT. There were two major types in left basal segmental bronchi, i.e., bifurcation (75%, 163/216), trifurcation (18%, 39/216), and they could also be identified at two typical sections of transverse thin-section CT. In conclusion, our study have offered simplified branching patterns of bronchi and demonstrated various unusual bronchial branching patterns perfectly with 3D images, and have also revealed how to identify the main branching patterns in transverse thin-section CT.