Evaluation of optical reflectance techniques for imaging of alveolar structure.
Three-dimensional (3-D) visualization of the fine structures within the lung parenchyma could advance our understanding of alveolar physiology and pathophysiology. Current knowledge has been primarily based on histology, but it is a destructive two-dimensional (2-D) technique that is limited by tissue processing artifacts. Micro-CT provides high-resolution three-dimensional (3-D) imaging within a limited sample size, but is not applicable to intact lungs from larger animals or humans. Optical reflectance techniques offer the promise to visualize alveolar regions of the large animal or human lung with sub-cellular resolution in three dimensions. Here, we present the capabilities of three optical reflectance techniques, namely optical frequency domain imaging, spectrally encoded confocal microscopy, and full field optical coherence microscopy, to visualize both gross architecture as well as cellular detail in fixed, phosphate buffered saline-immersed rat lung tissue. Images from all techniques were correlated to each other and then to corresponding histology. Spatial and temporal resolution, imaging depth, and suitability for in vivo probe development were compared to highlight the merits and limitations of each technology for studying respiratory physiology at the alveolar level.
Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Parkman Street, RSL 160, Boston, Massachusetts 02114, USA.
Carolin I
CI
Unglert
Eman
E
Namati
William C
WC
Warger
Linbo
L
Liu
Hongki
H
Yoo
DongKyun
D
Kang
Brett E
BE
Bouma
Guillermo J
GJ
Tearney
D000818:Animals; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D018613:Microscopy, Confocal / Q000295:instrumentation*; D008857:Microscopy, Interference / Q000295:instrumentation*; D011650:Pulmonary Alveoli / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity