Optical coherence tomography-based contact indentation for diaphragm mechanics in a mouse model of transforming growth factor alpha induced lung disease

Abstract

This study tested the utility of optical coherence tomography (OCT)-based indentation to assess mechanical properties of respiratory tissues in disease. Using OCT-based indentation, the elastic modulus of mouse diaphragm was measured from changes in diaphragm thickness in response to an applied force provided by an indenter. We used a transgenic mouse model of chronic lung disease induced by the overexpression of transforming growth factor-alpha (TGF-α), established by the presence of pleural and peribronchial fibrosis and impaired lung mechanics determined by the forced oscillation technique and plethysmography. Diaphragm elastic modulus assessed by OCT-based indentation was reduced by TGF-α at both left and right lateral locations (p < 0.05). Diaphragm elastic modulus at left and right lateral locations were correlated within mice (r = 0.67, p < 0.01) suggesting that measurements were representative of tissue beyond the indenter field. Co-localised images of diaphragm after TGF-α overexpression revealed a layered fibrotic appearance. Maximum diaphragm force in conventional organ bath studies was also reduced by TGF-α overexpression (p < 0.01). Results show that OCT-based indentation provided clear delineation of diseased diaphragm, and together with organ bath assessment, provides new evidence suggesting that TGF-α overexpression produces impairment in diaphragm function and, therefore, an increase in the work of breathing in chronic lung disease.Optical coherence tomography (OCT) is an interferometric imaging technique that forms volumetric images of tissue structure based on contrast generated by the back-scattering of light waves 1 . In the respiratory field, an increasing number of new applications for OCT are emerging 2 . Various endoscopic, needle and bench top OCT systems have been used to measure lumen dimensions in small 3 , large 4, 5 and upper airways 6 , to assess wall morphology and thickness 4,7 , and to visualise individual alveoli 8 . However, one feature of OCT in the respiratory

Optical Interferometric Fringe Pattern-Incorporated Spectrum Calibration Technique for Enhanced Sensitivity of Spectral Domain Optical Coherence Tomography

“…Optical coherence tomography (OCT) enables micrometer-resolution biomedical imaging to be performed in real time [1][2][3]. Due to its capability to perform non-invasive inspection, OCT has been extensively utilized and featured in numerous scientific research and clinical studies [4][5][6][7][8][9][10]. In addition to its medical applications, spectral domain OCT (SD-OCT) based field inspections have also been applied to industrial and agricultural materials [11][12][13][14][15][16].…”

Non-Invasive Morphological Characterization of Rice Leaf Bulliform and Aerenchyma Cellular Regions Using Low Coherence Interferometry

“…During the last decade, OCT has been employed for various agricultural applications, since it can overcome the disadvantages of existing agricultural techniques. The potential applicability of OCT for agriculture was demonstrated at numerous attempts by our group conducting studies for quality inspection of fruit [34,35], seed [36,37], and leaf specimens [38][39][40][41], and seed growth [42][43][44] speed measurements recently.…”