Abstract
Objective
In conventional in vivo microscopy, a three dimensional illustration of tissue is lacking. Concerning the microscopic analysis of the pulmonary alveolar network, surgical preparation of the thorax and fixation of the lung is required to place the microscope’s objective. These effects may have influence on the mechanical behaviour of alveoli. Relatively new methods exist for in vivo microscopy being less invasive and enabling an observation without fixation of the lung. The aim of this study was to compare a fibered confocal laser scanning microscopy (FCLSM) with optical coherence tomography (OCT) in a mouse and a rabbit model. Moreover, FCLSM was also used endoscopically in the rabbit model.
Methods
Smallest possible thoracic windows were excised at the lower margin of the upper right lung lobe and an interpleural catheter inserted before re-coverage with a transparent membrane foil. The OCT-scanner was positioned by a motor driven translation stage. The imaging was gated to endinspiratory plateau. For CLSM, Fluorescein 0.1% was given into the central venous streak line. The confocal probe with a diameter of 650 µm was carefully positioned at the very same lung region. Images were directly recorded real-time and the observed region qualitatively compared with FD-OCT images. Additionally, in the rabbit model, CLSM was used endoscopically under bronchoscopic sight control. In a post-processing analysis, images taken were analyzed and compared by using an “air index” (AI).
Results
In the mouse model, the very same region could be re-identified with both techniques. Concerning alveolar shape and size, qualitatively comparable images could be gained. The AI was 40.5% for the OCT and 40.1% for the CLSM images. In the rabbit, even an endoscopic view on alveoli was possible. Likewise AI was 43.2% for CLSM through the thoracic window and 43.6% from endoscopically. For the OCT an AI of 44.6% was analysed in the rabbit model.
Conclusions
Both FD-OCT and CLSM provide high-resolution images of alveolar structure giving depth information that is beneficial to conventional microscopy. CLSM also facilitates endoscopic view on alveoli being well comparable to images gained through a thoracic window.
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References
Schiller HJ, Steinberg J, Halter J, McCann U, DaSilva M, Gatto LA, et al. Alveolar inflation during generation of a quasi-static pressure/volume curve in the acutely injured lung. Crit Care Med. 2003;31(4):1126–33.
Halter JM, Steinberg JM, Schiller HJ, DaSilva M, Gatto LA, Landas S, et al. (Positive end-expiratory pressure after a recruitment maneuver prevents both alveolar collapse and recruitment/derecruitment. Am J Respir Crit Care Med. 2003;167(12):1620–6.
Steinberg J, Schiller HJ, Halter JM, Gatto LA, DaSilva M, Amato M, et al. Tidal volume increases do not affect alveolar mechanics in normal lung but cause alveolar overdistension and exacerbate alveolar instability after surfactant deactivation. Crit Care Med. 2002;30(12):2675–83.
Schiller HJ, McCann UG, Carney DE, Gatto LA, Steinberg JM, Nieman GF. Altered alveolar mechanics in the acutely injured lung. Crit Care Med. 2001;29(5):1049–55.
Halter JM, Steinberg JM, Gatto LA, Dirocco JD, Pavone LA, Schiller HJ, et al. Effect of positive end-exspiratory pressure and tidal volume on alveolar instability-induced lung injury. Crit Care. 2007;11(1):R20.
Pavone LA, Albert S, Carney D, Gatto LA, Halter JM, Nieman GF. Injurious mechanical ventilation in the normal lung causes a progressive pathologic change in dynamic alveolar mechanics. Crit Care. 2007;11(3):R64.
DiRocco JD, Pavone LA, Carney DE, Lutz CJ, Gatto LA, Landas SK, et al. Dynamic alveolar mechanics in four models of lung injury. Intensive Care Med. 2006;32(1):140–8.
Huang D, Swanson EA, Lin CP, Schuman JS, Stinson WG, Chang W, et al. Optical coherence tomography. Science. 1991;254:1178–81.
Häusler G, Lindner MW. Coherence radar and spectral radar—new tool for dermatological diagnosis. J Biomed Opt. 1998;3(1):21–31.
Fercher AF, Hitzenberger CK, Kamp G, El-Zaiat SY. Measurement of intraocular distances by backscattering spectral interferometry. Opt Commun. 1995;117:43–8.
Popp A, Wendel M, Knels L, Kocht T, Koch E. Imaging of the three-dimensional alveolar structure and the alveolar mechanics of a ventilated and perfused isolated rabbit lung with Fourier domain optical coherence tomography. J Biomed Opt. 2006;11(1):014015.
Carney D, DiRocco J, Nieman G. Dynamic alveolar mechanics and ventilator-induced lung injury. Crit Care Med. 2005;33:S122–8.
Le Goualher G, Perchant A, Genet M, Cavé C, Viellerobe B, Bérier F, Abrat B, Ayache N. Towards optical biopsies with an integrated fibered confocal fluorescence microscope. In: Lecture notes in computer science. Vol. 3217(II). Berlin/Heidelberg: Springer; 2001; 761–768.
Thiberville L, Moreno-Swirc S, Vercauteren T, Peltier E, Cavé C, Bourg Heckly G. In vivo imaging of the bronchial wall microstructure using fibered confocal fluorescence microscopy. Am J Respir Crit Care Med. 2007;175(1):22–3.
Tabuchi A, Mertens M, Kuppe H, Pries AR, Kuebler WM. Intravital microscopy of the murine pulmonary microcirculation. J Appl Physiol. 2008;104:338–46.
Acknowledgments
The study was supported by research grant KU 1372/5-1 from the “Deutsche Forschungsgesellschaft (DFG)”.
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Bickenbach J, Dembinski R, Czaplik M, Meissner S, Tabuchi A, Mertens M, Knels L, Schroeder W, Pelosi P, Koch E, Kuebler WM, Rossaint R, Kuhlen R. Comparison of two in vivo microscopy techniques to visualize alveolar mechanics.
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Bickenbach, J., Dembinski, R., Czaplik, M. et al. Comparison of two in vivo microscopy techniques to visualize alveolar mechanics. J Clin Monit Comput 23, 323–332 (2009). https://doi.org/10.1007/s10877-009-9200-1
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DOI: https://doi.org/10.1007/s10877-009-9200-1