Kashif Ali Khan

Optimizing parameters of an open-source airway segmentation algorithm using different CT images

Background Computed tomography (CT) helps physicians locate and diagnose pathological conditions. In some conditions, having an airway segmentation method which facilitates reconstruction of the airway from chest CT images can help hugely in the assessment of lung diseases. Many efforts have been made to develop airway segmentation algorithms, but methods are usually not optimized to be reliable across different CT scan parameters.MethodsIn this paper, we present a simple and reliable semi-automatic algorithm which can segment tracheal and bronchial anatomy using the open-source 3D Slicer platform. The method is based on a region growing approach where trachea, right and left bronchi are cropped and segmented independently using three different thresholds. The algorithm and its parameters have been optimized to be efficient across different CT scan acquisition parameters. The performance of the proposed method has been evaluated on EXACT’09 cases and local clinical cases as well as on a breathing pig lung phantom using multiple scans and changing parameters. In particular, to investigate multiple scan parameters reconstruction kernel, radiation dose and slice thickness have been considered. Volume, branch count, branch length and leakage presence have been evaluated. A new method for leakage evaluation has been developed and correlation between segmentation metrics and CT acquisition parameters has been considered.ResultsAll the considered cases have been segmented successfully with good results in terms of leakage presence. Results on clinical data are comparable to other teams’ methods, as obtained by evaluation against the EXACT09 challenge, whereas results obtained from the phantom prove the reliability of the method across multiple CT platforms and acquisition parameters. As expected, slice thickness is the parameter affecting the results the most, whereas reconstruction kernel and radiation dose seem not to particularly affect airway segmentation.ConclusionThe system represents the first open-source airway segmentation platform. The quantitative evaluation approach presented represents the first repeatable system evaluation tool for like-for-like comparison between different airway segmentation platforms. Results suggest that the algorithm can be considered stable across multiple CT platforms and acquisition parameters and can be considered as a starting point for the development of a complete airway segmentation algorithm.

Navigational Bronchoscopy for Early Lung Cancer: A Road to Therapy

Peripheral lung nodules remain challenging for accurate localization and diagnosis. Once identified, there are many strategies for diagnosis with heterogeneous risk benefit analysis. Traditional strategies such as conventional bronchoscopy have poor performance in locating and acquiring the required tissue. Similarly, while computerized-assisted transthoracic needle biopsy is currently the favored diagnostic procedure, it is associated with complications such as pneumothorax and hemorrhage. Video-assisted thoracoscopic and open surgical biopsies are invasive, require general anesthesia and are therefore not a first-line approach. New techniques such as ultrathin bronchoscopy and image-based guidance technologies are evolving to improve the diagnosis of peripheral lung lesions. Virtual bronchoscopy and electromagnetic navigation systems are novel technologies based on assisted-computerized tomography images that guide the bronchoscopist toward the target peripheral lesion. This article provides a comprehensive review of these emerging technologies.

Evaluation of a novel tracking system in a breathing lung model.

We present the evaluation of an electromagnetic position tracking system for use with virtual bronchoscopy systems. Our system utilises a planar magnetic coil array and commercially available search coil sensors. Experimental results show the EM tracking accuracy to be in the range of 11.5mm, which is comparable to both commercial and research systems. The use of a bench-top breathing lung model is used to verify system operation in the in vitro setting. A novel fiducial-free registration method is implemented to reduce errors resulting from inaccurate landmark identification commonly associated with point-based registration. After registration, there is good agreement between the measured position of the sensor probe during endoscopic navigation and the lung airways as visualised in a 3D model of the phantom.

Bronchoscopy in the investigation of outpatients with hemoptysis at a lung cancer clinic

BACKGROUND In the investigation of lung cancer, current practice in many healthcare systems would support bronchoscopy regardless of CT findings in patients with hemoptysis. We sought to identify the cause, the diagnostic yield of CT and bronchoscopy and the requirement for bronchoscopy in at risk patients with hemoptysis with a normal CT scan through our rapid access lung cancer clinic (RALC). METHODS Initially, a chart review was performed on all patients with hemoptysis (2011-2012) and thereafter a prospective analysis was performed (2013-2016). RESULTS Our analysis represents the largest study to date in outpatients with hemoptysis. In our retrospective study, 155 patients reported hemoptysis. Causes were lower respiratory tract infections (RTIs) (47%) and lung cancer (16%). Our prospective study included 182 patients. The causes of hemoptysis were RTIs (50%) and lung cancer (18%). There were no false negative CT-scans for lung cancer. 47/57 present with lung cancer underwent bronchoscopy and 43/47 were positive for lung cancer (92%). Patients with hemoptysis and lung cancer have a higher stage of malignancy with a predominance of squamous cell lung carcinoma. Smoking status, the duration of hemoptysis or description of hemoptysis were not predictive of lung cancer however lung cancer was not identified in patients age <50. CONCLUSIONS One sixth of patients presenting with hemoptysis to our lung cancer clinic had lung cancer. No patient identified with cancer related haemoptysis had a CT negative for lung cancer and a combination of bronchoscopy plus endobronchial ultrasound trans-bronchial needle aspiration (EBUS-TBNA) in those patients with a CT suspicious of lung cancer is 92% sensitive for lung cancer causing hemoptysis.

Pre-clinical validation of virtual bronchoscopy using 3D Slicer

PurposeLung cancer still represents the leading cause of cancer-related death, and the long-term survival rate remains low. Computed tomography (CT) is currently the most common imaging modality for lung diseases recognition. The purpose of this work was to develop a simple and easily accessible virtual bronchoscopy system to be coupled with a customized electromagnetic (EM) tracking system for navigation in the lung and which requires as little user interaction as possible, while maintaining high usability.MethodsThe proposed method has been implemented as an extension to the open-source platform, 3D Slicer. It creates a virtual reconstruction of the airways starting from CT images for virtual navigation. It provides tools for pre-procedural planning and virtual navigation, and it has been optimized for use in combination with a

P282 The design and validation of a novel semiautomatic lung navigation platform

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Ivacaftor therapy in siblings with cystic fibrosis-the potential implications of Itraconazole in dosage and efficacy.

5∘ of freedom EM tracking sensor. Performance of the algorithm has been evaluated in ex vivo and in vivo testing.ResultsDuring ex vivo testing, nine volunteer physicians tested the implemented algorithm to navigate three separate targets placed inside a breathing pig lung model. In general, the system proved easy to use and accurate in replicating the clinical setting and seemed to help choose the correct path without any previous experience or image analysis. Two separate animal studies confirmed technical feasibility and usability of the system.ConclusionsThis work describes an easily accessible virtual bronchoscopy system for navigation in the lung. The system provides the user with a complete set of tools that facilitate navigation towards user-selected regions of interest. Results from ex vivo and in vivo studies showed that the system opens the way for potential future work with virtual navigation for safe and reliable airway disease diagnosis.

Automated Catheter Navigation With Electromagnetic Image Guidance

During routine endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) procedures, especially with biopsy of lymph nodes in or around the left upper lobe, frequent reports have noted the loss of ultrasound image and needle angulation leading to an inability to biopsy nodes visualised by EBUS. The aim of this research was to investigate and compare this loss of angulation with commercially available scopes. Bench-top experiments and a clinical case study demonstrated the varying loss of scope angulation, flexibility and manoeuvrability with different scopes and biopsy instruments leading to procedural implications. Improvements in both the EBUS scope and needle characteristics are required to overcome this limitation which has implications in bronchoscope navigation and the diagnostic yield of EBUS-TBNA.