Radiological imaging as the basis for a simulation software of ventilation in the tracheo-bronchial tree

Abstract

The inhaled route is a promising new way for administering drugs to the human body. Flow and particle deposition in the human respiratory tract depends on the individual's anatomy as well as on the drug composition. A European Framework V Program supported project is currently developing a simulation tool for assessment of drug distribution and deposition. This tool relies heavily on the input of radiological data sets, which are obtained in humans. Both high temporal and spatial resolutions are required, and CT and MRI (including hyperpolarized helium-3 MRI) are applied. The radiological data are integrated into computation fluid dynamics software, which is capable of assessing air-flow profiles and compartmental behaviours. This is complemented by pharmacokinetic models, which should result in a simulation tool that will be of use for the theoretical design of new inhaled therapies. This article describes the special imaging requirements of each region of the respiratory tract and the feasibility of these sophisticated radiological techniques with a view of using these data in a simulation model of the lung.

Homogenization of a multiscale viscoelastic model with nonlocal damping, application to the human lungs

“…Such models are certainly helpful for understanding the respiration mechanisms, but cannot yield precise information on the coupled 3D displacement of the parenchyma and airflow. Fully resolved flow computations are possible for the upper airways and the proximal part of the bronchial tree [7,15,23], but usually choose a set of ad hoc boundary conditions on the part of the tree which has been cut off. In [4], a coupled ventilation model was developed to include the parenchyma, represented by a simple spring model and connected to the ends of the upper part of the bronchial tree by a resistance.…”

Bridging the Gap Between Science and Clinical Efficacy: Physiology, Imaging, and Modeling of Aerosols in the Lung

“…(59,(75)(76)(77)(78)(79) More recently, CFD applications have used surface models derived from imaging data from individual subjects. (80)(81)(82)(83) These models typically comprise the upper respiratory tract consisting of the oral airways, pharynx, and larynx, and upper lung airways from the trachea extending down through several generations of the lung. The limiting factor in determining how far down into the lung patientbased CFD models can go is driven by the resolution of the scanning procedure.…”

Computer-Assisted Visualization of Central Lung Tumours Based on 3-Dimensional Reconstruction

“…There is currently no generally available software for CT-based division of the lung into lobes and segments. There are the following additional challenges when segmenting the supply systems, especially in the case of the lungs: In the segmentation of the bronchial tree, on the one hand, the structures that take a horizontal course in the internal regions are rendered very bright and, on the other hand, the centres of the thinner bronchi that take a diagonal course through the volume are no longer coherent within the meaning of neighbouring relationships in the voxel grid in the discrete reconstruction [Park W et al 1998, Prêteux F et al 1999, Ley S et al 2002. The focus of current research is the stabilization of automatic segmentation methods that produce a satisfactory segmentation result without interaction from the user [Tschirren J et al 2005b, Schalthölter T et al 2002, Hoffmann EA et al 2003].…”