Measurement of the tortuosity of the trachea.

<p>Images in the coronal (A) and sagittal (B) planes are shown. In this scheme, <i>L</i> is the length of the trachea (the total length of 'ab', shown in blue) and <i>vd</i> is the vectorial distance between the points at the extremities (the length of the shortest possible path between 'a’ and ‘b', shown in red).</p

Relationship between forced vital capacity (FVC) and eccentricity of the trachea (r = -0.57, p = 0.002).

<p>Scleroderma group (1) = scleroderma group with no pulmonary involvement/limited interstitial lung disease; scleroderma group (2) = scleroderma group with extensive interstitial lung disease.</p

3D reconstruction, cross-sectional planes, skeleton and indication of the plane used for representation.

<p>The letters A to F and the values ​​for the selected plane indicate, respectively: (*A) area (182.4 mm²), which is the product of the pixel size and the number of pixels in the region (in this figure, the area is shown in yellow and includes the red line that demarcates the perimeter); (*B) perimeter (47.3 mm), which is the length of the line indicated in red; (*C) eccentricity (0.35), which is indicated by the equivalent ellipse drawn in blue; (*D) equivalent diameter (15.2 mm), which is the circle of area equivalent to the cross-sectional area; (*E) major diameter (15.8 mm), which is the longest segment of the equivalent ellipse (indicated by the inner line); and (*F) minor diameter (14.8 mm), which is the smallest segment (indicated by the inner line).</p

Pearson’s correlation coefficients for CT trachea volumetry, pulmonary fibrosis and pulmonary function.

<p>Pearson’s correlation coefficients for CT trachea volumetry, pulmonary fibrosis and pulmonary function.</p

Variables of CT trachea volumetry according to group.

<p>Variables of CT trachea volumetry according to group.</p

Demographic characteristics, clinical data, pulmonary function and computed tomography scores of patients with scleroderma and of patients in the control group.

<p>Demographic characteristics, clinical data, pulmonary function and computed tomography scores of patients with scleroderma and of patients in the control group.</p

Skeletonization process of the trachea.

<p>Three-dimensional reconstruction of the trachea of one study participant in two planes (A and B). The median values showed in the ten planes of square cross-sections are as follows: area = 184.5 mm²; perimeter = 47.6 mm; eccentricity = 0.51; equivalent diameter = 15.3 mm; major diameter = 15.9 mm; minor diameter = 14.4 mm; and tortuosity = 1.027.</p