Pre-clinical validation of virtual bronchoscopy using 3D Slicer

CT-Based Evaluation of the Shape of the Diaphragm Using 3D Slicer

The diaphragm is the main inspiratory muscle and separates the thorax and the abdomen. In COPD, the evaluation of the diaphragm shape is clinically important, especially in the case of hyperinflation. However, delineating the diaphragm remains a challenge as it cannot be seen entirely on CT scans. Therefore, the lungs, ribs, sternum, and lumbar vertebrae are used as surrogate landmarks to delineate the diaphragm. We herein describe a CT-based method for evaluating the shape of the diaphragm using 3D Slicer-a free software that allows delineation of the diaphragm landmarks-in ten COPD patients. Using the segmentation performed with 3D Slicer, the diaphragm shape was reconstructed with open-source Free Pascal Compiler. From this graduated model, the length of the muscle fibers, the radius of curvature, and the area of the diaphragm-the main determinants of its function-can be measured. Inter- and intra-user variabilities were evaluated with Bland and Altman plots and linear mixed models. Except for the coronal length (p = 0.049), there were not statistically significant inter- or intra-user differences (p values ranging from 0.326 to 0.910) suggesting that this method is reproducible and repeatable. In conclusion, 3D Slicer can be applied to CT scans for determining the shape of the diaphragm in COPD patients.

Open-source algorithm and software for computed tomography-based virtual pancreatoscopy and other applications

Pancreatoscopy plays a significant role in the diagnosis and treatment of pancreatic diseases. However, the risk of pancreatoscopy is remarkably greater than that of other endoscopic procedures, such as gastroscopy and bronchoscopy, owing to its severe invasiveness. In comparison, virtual pancreatoscopy (VP) has shown notable advantages. However, because of the low resolution of current computed tomography (CT) technology and the small diameter of the pancreatic duct, VP has limited clinical use. In this study, an optimal path algorithm and super-resolution technique are investigated for the development of an open-source software platform for VP based on 3D Slicer. The proposed segmentation of the pancreatic duct from the abdominal CT images reached an average Dice coefficient of 0.85 with a standard deviation of 0.04. Owing to the excellent segmentation performance, a fly-through visualization of both the inside and outside of the duct was successfully reconstructed, thereby demonstrating the feasibility of VP. In addition, a quantitative analysis of the wall thickness and topology of the duct provides more insight into pancreatic diseases than a fly-through visualization. The entire VP system developed in this study is available at https://github.com/gaoyi/VirtualEndoscopy.git.

Cardia Laxity under Retroflexed Endoscopy Is a Reflection of Esophageal Hiatus Enlargement

Methods

Information from patients who underwent endoscopy and CT scan in our department was collected and analyzed retrospectively. Three-dimensional reconstruction of hiatus from CT images was performed using 3DSlicer software, and the degree of esophageal hiatus enlargement was compared with the degree of gastroesophageal laxity under retroflexed endoscopy.

Results

Information from 104 patients was included for analysis. The Spearman correlation coefficient was 0.617 (p ≤ 0.001). When subgroup correlation analysis was performed according to the presence of hiatal hernia on CT, the Spearman correlation coefficient was 0.816 (p ≤ 0.001) in the hernia group and 0.351 (p = 0.002) in the nonhernia group. The proportion of hiatal hernia and severe esophagitis was increasing gradually with the degree of gastroesophageal laxity.

Conclusion

The degree of gastroesophageal laxity (cardia or hiatus) under retroflexed endoscopy reflects the degree of esophageal hiatus enlargement; with the degree of gastroesophageal laxity increasing, the proportion of HH and severe esophagitis increases gradually. This may be useful for physicians in China to guide themselves in the selection of patients for endoscopic antireflux treatment.

Localization and shape of stenoses in central lung carcinoma - Sensitivity and precision of MDCT VB and FB

The objective is to present diagnostic capabilities of virtual bronchoscopy (VB) and fiberoptic bronchoscopy (FB) for determining the localization and shape of stenoses in patients with central lung carcinoma. A systematic study was performed on 220 patients aged 11-83 (54.36±17.24) years with endobronchial disease using the FB and VB methods during the 2013-2017 period. Central carcinoma of the lung was found on VB in 130 patients and on FB in 120 patients. Other nosologic diseases were found in 22 patients. Right localization of central carcinoma prevailed over left localization in both sexes. A significant difference in the localization criterion was found in female patients examined by VB (U-test, p=0.01). VB and FB yielded 86.5% vs. 91.60% precision and 85% vs. 94.5% sensitivity. In conclusion, VB was found to be a successful noninvasive method for determining the localization of lung tumors and shape of stenoses, which are essential in the diagnosis of malignant processes.

BronchoX: bronchoscopy exploration software for biopsy intervention planning

Virtual bronchoscopy (VB) is a non-invasive exploration tool for intervention planning and navigation of possible pulmonary lesions (PLs). A VB software involves the location of a PL and the calculation of a route, starting from the trachea, to reach it. The selection of a VB software might be a complex process, and there is no consensus in the community of medical software developers in which is the best-suited system to use or framework to choose. The authors present Bronchoscopy Exploration (BronchoX), a VB software to plan biopsy interventions that generate physician-readable instructions to reach the PLs. The authors' solution is open source, multiplatform, and extensible for future functionalities, designed by their multidisciplinary research and development group. BronchoX is a compound of different algorithms for segmentation, visualisation, and navigation of the respiratory tract. Performed results are a focus on the test the effectiveness of their proposal as an exploration software, also to measure its accuracy as a guiding system to reach PLs. Then, 40 different virtual planning paths were created to guide physicians until distal bronchioles. These results provide a functional software for BronchoX and demonstrate how following simple instructions is possible to reach distal lesions from the trachea.