The feasibility of using in silico model throats for population studies of regional drug deposition

What is it about?

An emerging topic in the area of drug delivery to the lungs is that of in silico population studies aiming at identifying correlations between structural and functional airway parameters for particular patient groups and regional deposition outcomes. Such in silico population studies entail the execution of large numbers of costly simulations and thus the pressing need to find ways to minimize computational cost. Such in silico population studies would rely on the hundreds of CT-images available in diagnostic centers and hospitals around Europe and worldwide. However, most chest CTs stop at the lower trachea and exclude the mouth-throat area. Thus, in this study, we were motivated by these considerations to explore whether it would be possible to obtain accurate estimates of regional deposition in the upper tracheobronchial tree without having to simulate the flow and aerosol transport in the patient specific extrathoracic airways, because in such a case, one could use a small number in silico model throats that are representative of population cross sections. For this purpose, we merged three very different mouth-throat geometries with the same tracheobronchial airways and performed Large Eddy Simulations under different inhalation rates. We were able to show that for particle sizes relevant to drug delivery applications, the deposition efficiencies in all segments of the tracheobronchial tree were practically identical irrespective of which extrathoracic airways were used. Of course, deposition fractions differed due to the different amounts of filtering that the different mouth-throats imposed. The end conclusion is that indeed in silico model mouth-throats can be used in the context of in silico population studies of regional deposition in the upper airways. An important outcome that promises to help advance the emerging field of in silico populations studies in the lungs.

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Why is it important?

The end conclusion is that indeed in silico model mouth-throats can be used in the context of in silico population studies of regional deposition in the upper airways. An important outcome that promises to help advance the emerging field of in silico populations studies in the lungs.

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