title: Morphometric differences between central vs. surface acini in A/J mice using high-resolution micro-computed tomography.
abstract: Through interior tomography, high-resolution microcomputed tomography (μCT) systems provide the ability to nondestructively assess the pulmonary acinus at micron and submicron resolutions. With the application of systematic uniform random sampling (SURS) principles applied to in situ fixed, intact, ex vivo lungs, we have sought to characterize morphometric differences in central vs. surface acini to better understand how well surface acini reflect global acinar geometry. Lungs from six mice (A/J strain, 15-20 wk of age) were perfusion fixed in situ and imaged using a multiresolution μCT system (Micro XCT 400, Zeiss). With the use of lower-resolution whole lung images, SURS methods were used for identification of central and surface foci for high-resolution imaging. Acinar morphometric metrics included diameters, lengths, and branching angles for each alveolar duct and total path lengths from entrance of the acinus to the terminal alveolar sacs. In addition, acinar volume, alveolar surface area, and surface area/volume ratios were assessed. A generation-based analysis demonstrated that central acini have significantly smaller branch diameters at each generation with no significant increase in branch lengths. In addition to larger-diameter alveolar ducts, surface acini had significantly increased numbers of branches and terminal alveolar sacs. The total path lengths from the acinar entrance to the terminal nodes were found to be higher in the case of surface acini. Volumes and surface areas of surface acini are greater than central acini, but there were no differences in surface/volume ratios. In conclusion, there are significant structural differences between surface and central acini in the A/J mouse.
authors.affiliation: Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa;
authors.forename: Abhilash S
authors.initials: AS
authors.lastname: Kizhakke Puliyakote
authors.affiliation: Department of Radiology, University of Iowa, Iowa City, Iowa;
authors.forename: Dragoş M
authors.initials: DM
authors.lastname: Vasilescu
authors.affiliation: Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa;
authors.forename: John D
authors.initials: JD
authors.lastname: Newell
authors.affiliation: Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; Department of Biomedical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia;
authors.forename: Ge
authors.initials: G
authors.lastname: Wang
authors.affiliation: University of Bern, Bern, Switzerland.
authors.forename: Ewald R
authors.initials: ER
authors.lastname: Weibel
authors.affiliation: Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa; Department of Medicine, University of Iowa, Iowa City, Iowa; eric-hoffman@uiowa.edu.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Hoffman
mesh_terms: D061354:Acinar Cells / Q000502:physiology*; D000818:Animals; D051379:Mice; D011650:Pulmonary Alveoli / Q000502:physiology; D055114:X-Ray Microtomography / Q000379:methods
keywords: acinar structure; central line-based morphometry; lung parenchyma; pulmonary imaging; quantitative CT; systematic uniform random sampling