Last Word on Viewpoint: Could lobar flow sequencing account for convection-dependent ventilation heterogeneity in normal man?
2016; American Physiological Society; Volume: 121; Issue: 2 Linguagem: Inglês
10.1152/japplphysiol.00513.2016
ISSN8750-7587
AutoresSylvia Verbanck, Manuel Paiva,
Tópico(s)Thermal Regulation in Medicine
ResumoPerspectivesLast Word on Viewpoint: Could lobar flow sequencing account for convection-dependent ventilation heterogeneity in normal man?Sylvia Verbanck and Manuel PaivaSylvia VerbanckRespiratory Division, University Hospital UZ Brussel, Brussels, Belgium; and and Manuel PaivaRespiratory Division, University Hospital Erasme, Université Libre de Bruxelles, Brussels, BelgiumPublished Online:19 Aug 2016https://doi.org/10.1152/japplphysiol.00513.2016MoreSectionsPDF (26 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat to the editor: We thank Collier et al. (see Ref. 1) for providing realistic perspectives toward the experimental investigation of convective ventilation heterogeneity. The authors point toward an important aspect of imaging: the spatial resolution to quantify mechanisms that are potentially operational at various length scales. One large-scale mechanism of ventilation heterogeneity was identified a long time ago by Milic-Emili et al. (3), and a first step in the validation of more recent ventilation imaging studies (e.g., 4) often consists of reproducing the gravitational ventilation gradient. However, to identify the potential mechanisms of convective ventilation heterogeneity that are not gravitational in origin (5), it is important to know whether two adjacent voxels (and their expansion dynamics) in a 3D ventilation imaging map (2) belong to the same cul-de-sac and where their parent branch is. Indeed, if two voxels belonging to different lung entities show a difference in ventilation, the bronchial generation of their parent branch roughly corresponds to the lung depth where ventilation heterogeneity that we observe at the mouth finds it origin.In clustering all voxels of a ventilation map into anatomical entities with a common pathway to the mouth may lie the true value of complex 3D models that are as realistic as possible (i.e., measured airways down to generation 5–7 and space-filling airways grown within the actual lung outer boundaries). By overlaying such 3D airway geometries with corresponding ventilation maps, it should be possible to identify which clusters of airways supply which lung entities (belonging to the same cul-de-sac). This information is crucial to identify the lung depth that is responsible for the ventilation heterogeneity that we measure noninvasively at the mouth.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the author(s).AUTHOR CONTRIBUTIONSS.A.V. drafted manuscript; S.A.V. and M.P. edited and revised manuscript; S.A.V. and M.P. approved final version of manuscript.REFERENCES1. Collier G, Horn F, Wild J, Zuo L. Commentaries on Viewpoint: Could lobar flow sequencing account for convection-dependent ventilation heterogeneity in normal humans? J Appl Physiol; doi:10.1152/japplphysiol.00498.2016.Link | ISI | Google Scholar2. Horn FC, Deppe MH, Marshall H, Parra-Robles J, Wild JM. Quantification of regional fractional ventilation in human subjects by measurement of hyperpolarized 3He washout with 2D and 3D MRI. J Appl Physiol 116: 129–139, 2014.Link | ISI | Google Scholar3. Milic-Emili J, Henderson JA, Dolovich MB, Trop D, Kaneko K. Regional distribution of inspired gas in the lung. J Appl Physiol 21: 749–759, 1966.Link | ISI | Google Scholar4. Sá RC, Cronin MV, Henderson AC, Holverda S, Theilmann RJ, Arai TJ, Dubowitz DJ, Hopkins SR, Buxton RB, Prisk GK. Vertical distribution of specific ventilation in normal supine humans measured by oxygen-enhanced proton MRI. J Appl Physiol 109: 1950–1959, 2010.Link | ISI | Google Scholar5. Verbanck S, Linnarsson D, Prisk GK, Paiva M. Specific ventilation distribution in microgravity. J Appl Physiol 80: 1458–1465, 1996.Link | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: S. Verbanck, Respiratory Division, Univ. Hospital UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium (e-mail: sylvia.[email protected]be). Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation More from this issue > Volume 121Issue 2August 2016Pages 593-593 Copyright & PermissionsCopyright © 2016 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00513.2016PubMed27543660History Published online 19 August 2016 Published in print 1 August 2016 Metrics
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