Abstract
Aim Light microscopy is used as template in the evaluation and further development of medical imaging methods. Tissue shrinkage caused by histological processing is known to influence lung tissue dimensions. In diagnosis of COPD, computed tomography (CT) is widely used for automated airway measurement. The aim of this study was to compare histological and computed tomographic measurements of pig lung bronchi.
Methods Airway measurements of pig lungs were performed after freezing under controlled inflation pressure in a liquid nitrogen bath. The wall thickness of seven bronchi was measured via Micro-CT and CT using the integral-based method (IBM) and the full-width-at-half-maximum method (FWHM) automatically and histologically on frozen and paraffin sections. Statistical analysis was performed using the Wilcoxon test, Pearson's correlation coefficient with a significance level at p<0.05, scatter plots and Bland–Altman plots.
Results Bronchial wall thickness was smallest in frozen sections (median 0.71 mm) followed by paraffin sections (median 0.75 mm), Micro-CT (median 0.84 mm), and CT measurements using IBM (median 0.68 mm) and FWHM (median 1.69 mm). Statistically significant differences were found among all tested groups (p<0.05) except for CT IBM and paraffin and frozen sections and Micro-CT. There was high correlation between all parameters with statistical significance (p<0.05).
Conclusions Significant differences in airway measurement were found among the different methods. The absolute measurements with CT IBM were closest to the histological results followed by Micro-CT, whereas CT FWHM demonstrated a distinct divergence from the other groups.
Abstract
Automated measurement techniques advance diagnosis of lung diseases. Pig bronchi wall size varies between Micro-CT, CT IBM, CT FWHM and histology. CT IBM is closest to histological results, followed by Micro-CT. CT FWHM differs highly from all other groups. https://bit.ly/3iRXSrv
Footnotes
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Conflict of interest: V.H. Schmitt has nothing to disclose.
Conflict of interest: C. Schmitt has nothing to disclose.
Conflict of interest: D. Hollemann has nothing to disclose.
Conflict of interest: A. Mamilos has nothing to disclose.
Conflict of interest: W. Wagner has nothing to disclose.
Conflict of interest: O. Weinheimer reports grants from DFG German Research Foundation during the conduct of the study.
Conflict of interest: C. Brochhausen has nothing to disclose.
Support statement: This study was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft – DFG, WE 4691/2-1). Funding information for this article has been deposited with the Crossref Funder Registry.
- Received July 15, 2020.
- Accepted September 14, 2020.
- Copyright ©ERS 2020
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