Preoperative assessment of obstruction with computed tomography image analysis

Graham, Scott M.; McLennan, Geoffrey; Funk, Gerry F.; Hoffman, Henry T.; McCulloch, Timothy M.; Cook-Granroth, Janice; Hoffman, Eric A.

doi:10.1053/ajot.2000.8379

Cited by 13 publications

(9 citation statements)

References 19 publications

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“…Airway abnormalities serve as the pathophysiologic basis for many pulmonary diseases, including gross abnormalities such as idiopathic subglottic stenosis (33) or the stenosis that follows prolonged intubation and mechanical ventilation, and the more subtle changes associated with asthmatic airway remodeling. Airway abnormalities or bronchoconstriction increase resistance and potentially alter the distribution of ventilation in addition to changing the fluid flow structures.…”

Section: Airway Resistancementioning

confidence: 99%

Airway Gas Flow

Tawhai

Lin

2011

Comprehensive Physiology

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Local characteristics of airflow and its global distribution in the lung are determined by interaction between resistance to flow through the airways and the compliance of the tissue, with tissue compliance dominating flow distribution in the healthy lung. Current understanding is that conceptualizing the airways of the lung as a system of smooth adjoined cylinders through which air traverses laminarly is insufficient for understanding flow and energy dissipation and is particularly poor for predicting physiologically realistic transport of particles by the airflow. With rapid advances in medical imaging, computer technologies, and computational techniques, computational fluid dynamics is now becoming a viable tool for providing detailed information on the mechanics of airflow in the human respiratory tract. Studies using such techniques have shown that the upper airway (specifically its development of a turbulent laryngeal jet in the trachea), airway geometry, branching and rotation angle, and the pattern of joining of successive bifurcations are important in determining airflow structures. It is now possible to compute airflow in physical domains that are anatomically accurate and subject specific, enabling comparisons among intersubjects, that among subjects of different ages, and that among different species.

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Section: Airway Resistancementioning

confidence: 99%

Airway Gas Flow

Tawhai

Lin

2011

Comprehensive Physiology

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“…An understanding of the structure-flow relationship is the first critical step in designing particulates to target specific sites in the lung, or for studying which populations are most susceptible to inhaled pollutants. Airway abnormalities serve as the pathophysiologic basis for many pulmonary diseases, including gross abnormalities such as idiopathic subglottic stenosis (Graham et al 2000) or the stenosis that follows prolonged intubation and mechanical ventilation, and the more subtle changes associated with asthmatic airway remodeling. A change to upper or central airway geometry also potentially alters the location of the isothermal saturation boundary (the location where inspired air reaches body temperature and saturation), and will alter mechanical shear stress acting on the airway mucosa.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the turbulent laryngeal jet and its effect on airflow in the human intra-thoracic airways

Lin

Tawhai

McLennan

et al. 2007

Respiratory Physiology & Neurobiology

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280

290

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A computational fluid dynamics technique is applied to understand the relative importance of the upper and intra-thoracic airways and their role in determining central airflow patterns with particular attention paid to the importance of turbulence. The geometry of the human upper respiratory tract is derived from volumetric scans of a volunteer imaged via multidetector-row computed tomography. Geometry 1 consists of a mouth piece, the mouth, the oropharynx, the larynx, and the intra-thoracic airways of up to 6 generations. Geometry 2 comprises only the intra-thoracic airways. The results show that a curved sheet-like turbulent laryngeal jet is observed only in geometry 1 with turbulence intensity in the trachea varying from 10% to 20%, whereas the turbulence in geometry 2 is negligible. The presence of turbulence is found to increase the maximum localised wall shear stress by three folds. The proper orthogonal decomposition analysis reveals that the regions of high turbulence intensity are associated with Taylor-Görtler-like vortices. We conclude that turbulence induced by the laryngeal jet could significantly affect airway flow patterns as well as tracheal wall shear stress. Thus airflow modeling, particularly subject specific evaluations, should consider upper as well as intra-thoracic airway geometry.

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“…External rendering, analogous to CT bronchography, depicts the external surface of the bronchial tree, whereas internal rendering, better known as virtual bronchoscopy, depicts the internal surface of the bronchial tree, allowing navigation of the tree ''endoscopically''. Both provide clinically useful images and allow qualitative assessment of airway shape and, in the case of external rendering, relationship to adjacent structures [41]. External rendering allows assessment of stenosis length to guide pre-operative stent selection [42,43].…”

Section: Measuring Airway Dimensions From Ct Datamentioning

confidence: 99%

Quantifying tracheobronchial tree dimensions: methods, limitations and emerging techniques

Williamson¹,

James²,

Phillips³

et al. 2009

Eur Respir J

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The ability to measure airway dimensions is important for clinicians, interventional bronchoscopists and researchers in order to accurately quantify structural abnormalities and track their changes over time or in response to treatment.Most quantitative airway measurements are based on X-ray computed tomography and, more recently, on multidetector computed tomography. Quantitative bronchoscopic techniques have also been developed, although these are less widely employed. Emerging techniques, including magnetic resonance imaging, endoscopic optical coherence tomography, endobronchial ultrasound and confocal endomicroscopy, provide new research tools with potential clinical applications.An understanding of issues related to the acquisition, processing and analysis of images, and how such issues impact on imaging the tracheobronchial tree, is essential in order to assess measurement accuracy and to make effective use of the newer methods. This article contributes to this understanding by providing a comprehensive review of current and emerging techniques for quantifying airway dimensions.KEYWORDS: Airway dimensions, confocal endomicroscopy, multidetector computed tomography, optical coherence tomography, videobronchoscopy A dvances over the past 20 yrs in medical imaging and bronchoscopy have heralded an era of unprecedented access to quantitative information on tracheobronchial structure and, increasingly, function. The expanding scope of technical advances challenges the ability of clinicians and researchers to keep abreast of recent developments and emerging techniques. Computed tomography (CT) and, to a lesser extent, bronchoscopy are the two imaging tools that have contributed most to our understanding of the airway in vivo and are used on a daily basis by clinicians in the management of airway diseases. Newer techniques, such as magnetic resonance imaging, optical coherence tomography, fibreoptic confocal endomicroscopy and endobronchial ultrasound, offer fresh insights into the way we view and quantify the airway.Over the coming years, the clinical applications of these newer techniques will be defined. As with endobronchial ultrasound, which has been adopted by interventional bronchoscopists in a little over a decade from its first reported use [1], it is likely that smoking-related lung diseases, such as bronchogenic cancer and chronic obstructive pulmonary disease (COPD), will drive the rapid development of new endoscopic imaging modalities and maintain the current pace of technical improvements of existing techniques, in particular CT. Initial applications of these techniques may focus on screening and surveillance of endobronchial malignancies and the use of real-time airway measurements during interventional procedures to deploy endobronchial stents. In these settings, accurate real-time quantitative imaging is advantageous.

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Preoperative assessment of obstruction with computed tomography image analysis

Cited by 13 publications

References 19 publications

Airway Gas Flow

Airway Gas Flow

Characteristics of the turbulent laryngeal jet and its effect on airflow in the human intra-thoracic airways

Quantifying tracheobronchial tree dimensions: methods, limitations and emerging techniques

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