Background: To explore the feasibility of the depth ratio method partitioning the lung parenchyma and the depth distribution of lung nodules in pulmonary segmentectomy.Methods: Based on the measurement units, patients were allocated to the chest group, the lobar group, and the symmetrical 3 sectors group. In each unit, the center of the respective bronchial cross-section was set as the starting point (O). Connecting the O point with the center of the lesion (A) and extending to the endpoint (B) on the pleural, the radial line (OB) was trisected to divide the outer, middle, and inner regions.The depth ratio and relevant regional distribution were simultaneously verified using 2-dimensional (2D) coronal, sagittal, and axial computed tomography images and 3-dimensional (3D) reconstruction images.Results: Two hundred and nine patients were included in this study. The median age was 53 (IQR, 44.5-62) years and 64 were males. The intra-group consistency of the depth ratio region partition was 100%. The consistency of the inter-group region partition differed among the three groups (Kappa values 0.511, 0.517, and 0.923). The chest group, lobar group, and symmetrical 3 sectors group had 69.4%, 26.3%, and 4.8% mediastinum disturbance, respectively (P<0.001). Conclusions:The depth ratio method in the symmetrical 3 sectors of the lung maximally eliminated the disturbance of the mediastinal structures and more accurately trisected the lung parenchymal in 3D space.Sublobar resection based on subsegments strategy is feasible for outer 2/3 pulmonary nodules when depth ratio is used as the measurement method.

Background: Identifying the distribution of pulmonary veins with three-dimensional reconstruction images is of great significance for surgical guidance. Existing models neglect the consistency of the bilateral superior pulmonary veins (SPVs) and lack a simple unified classification pattern. This study aimed to analyze the distributional features of bilateral SPVs, based on a cohort of patients undergoing CT examination. Methods: The three-dimensional computed tomography bronchography and angiography (3D-CTBA) images of 1,520 cases were retrospectively analyzed. The reconstructed images of the right upper lobes were read in 715 cases, and left upper lobes in 805 cases. Through symmetrical analysis, the circulation of main venous branches and the spatial relationships of confluences with adjacent bronchus were compared. Results: The SPVs of bilateral upper lobes showed common distributional features and were divided into three main types. The central vein type, the semi-central vein type, and the non-central vein type accounted for 83.35% [596], 7.84% [56], 8.11% [58] of the 715 cases with right scanning, and 25.71% [207], 62.61% [504], 10.81% [87] of the 805 cases with left scanning, respectively. There were 5 (0.70%) cases with rare variations in the right upper lobe and 7 (0.87%) in the left upper lobe. The attribution of intersubsegmental vein in the posterior segment (V 2 b) and its position relative to the anterior segmental bronchus (B 3 ) was the basis of classification in the right upper lobe, and the attribution of intersubsegmental vein in the apicoposterior segment (V 1+2 c) and its position relative to B 3 was the basis of classification in the left upper lobe. In this classification system, the branching pattern of the intersegmental vein between the apical segment and the anterior segment (V 1 b) in the right upper lobe, and the intersegmental vein between the apicoposterior segment and the anterior segment (V 1+ 2 a) in the left upper lobe were used for subdivision.Conclusions: Our modified system had a high degree of consistency in classifying SPVs in bilateral upper lobes, thus providing guidance for preoperative and intraoperative procedures.