1. New method for quantitative assessment of airway calibre using a stereovision fibreoptic bronchoscope 
A. Hayashi, S. Takanashi, T. Tsushima, J. Denpoya, K. Okumura, K. Hirota 
British Journal of Anaesthesia 
Volume 108, Issue 3, Pages (March 2012)
DOI: /bja/aer420
Copyright © 2012 The Author(s) Terms and Conditions

2. Fig 1
Principles of the measurement. The bronchoscope has two independent lenses at the tip to measure distance between the objective and centre of two lenses using the principle of triangulation. The distance ‘d' between the right and left lenses and the distance ‘f' which is the focal length of the lenses are known values. If certain measurement points are selected, corresponding measurement points (a, b, and c) on the right and left images are determined. Then, x, y, and z coordinates are calculated from the formula: x=d(b−a)/2(a+b), y=cd/(a+b), z=fd/(a+b).
British Journal of Anaesthesia  , DOI: ( /bja/aer420)
Copyright © 2012 The Author(s) Terms and Conditions

3. Fig 2
Correlation between the manufactured diameter (x) and measured diameter (y) using a stereovision fibreoptic bronchoscope (P<0.01, r=0.945, y=1.04x+0.46).
British Journal of Anaesthesia  , DOI: ( /bja/aer420)
Copyright © 2012 The Author(s) Terms and Conditions

4. Fig 3
Example of measurement images from stereovision bronchoscopy (a) and HRCT-based virtual bronchoscopy (b).
British Journal of Anaesthesia  , DOI: ( /bja/aer420)
Copyright © 2012 The Author(s) Terms and Conditions

5. Fig 4
Agreement between airway calibres measured using stereovision bronchoscopy and HRCT-based virtual bronchoscopy using Bland and Altman plots (a, the dotted line: 2 sd) and a least square linear regression line with Pearson's correlation coefficient (b: P<0.01, r=0.975, y=0.83x+0.91).
British Journal of Anaesthesia  , DOI: ( /bja/aer420)
Copyright © 2012 The Author(s) Terms and Conditions