Measurement of three-dimensional lung tree structures by using computed tomography

Abstract

A method was devised to computationally segment and measure three-dimensional pulmonary trees in situ. Bronchi and pulmonary vessels were computationally extracted from volumetric computed tomography data based on radiopacity differences between airway wall and airway lumen and between blood and parenchyma, respectively. The tree was reduced to a central axis to facilitate measurement of branch segment length and angle. Cross-sectional area was measured on a reconstructed computed tomography slice perpendicular to this central axis. The method was validated by scanning two Plexiglas phantoms and an intact lung. Reconstructed diameters in the phantoms were accurate for branches > 2 mm. In the lung airway branches between 1 and 2 mm in diameter were often unresolved when their angle of orientation with respect to the axis of the scanner was > 45 degrees. However, if a branch was resolved, its reconstructed diameter was little affected by orientation. This method represents a significant improvement in the analysis of complex pulmonary structures in three dimensions.

Computed tomographic imaging of the airways: relationship to structure and function

“…The isotropic voxels make it possible to measure airways in true cross-section at any location, using retrospective reconstruction of the images to achieve a cross-sectional image of the airway. A number of complex algorithms have been developed that allow this angle correction and measurement of the wall and lumen [1][2][3][4]. Therefore, studies can be tailored to the clinical or research question being asked in order to maximise image quality whilst minimising the radiation dose.…”

Effect of bronchial thermoplasty on airway distensibility

“…The images were reconstructed at a 1-mm slice thickness and a 5126512 matrix, using a 125-mm field of view and a high spatial frequency (resolution) algorithm, which enhanced edge detection, at a window level of -450 HU and a window width of 1,350 HU. These settings have been shown to provide accurate measurement of lumenal size as small as 0.5 mm in diameter [9,10]. For repeated airway measurements in a given dog within each experimental protocol, adjacent anatomic landmarks, such as airway or vascular branching points, were defined and used to measure the airway size at the same anatomic cross sections.…”

Investigation of Hyperpolarized 3He Magnetic Resonance Imaging Utility in Examining Human Airway Diameter Behavior in Asthma Through Comparison with High-Resolution Computed Tomography

“…Numerous algorithms have been developed to process the acquired MDCT data [3,[6][7][8][9][10][11][12]. Sophisticated software has been successfully developed for the visualization and 3D rendering of the airway tree [9,[11][12].…”