Table 1 Mean (±SD) values and 95% confidence intervals for radiographic measurements of the absolute, average, and normalized values of vertical tracheal diameter (VTD) at levels A (mid-C5), B (Ca-C7), and C (mid-T2–3) for 81 ‘healthy’ non-brachycephalic, small breed dogs
Variables | Mean ± SD | 95% CI | P-value < 0.05 | ||
|---|---|---|---|---|---|
Absolute vertical tracheal diameter (VTD)/mm | ANOVA test | Tukey’s test | Unpaired t-test | ||
Level A (Mid-C5), caudal cervical VTD | 13.4 ± 2.9 | 12.7–14.1 | A-B, P < 0.0001 | A-B, P < 0.0001 | |
Level B (Ca-C7), thoracic inlet VTD | 10.6 ± 2.7 | 10.0–11.2 | P < 0.0001 | A-C, P = 0.004 | A-C, P = 0.002 |
Level C (Mid-T2–3), intrathoracic VTD | 11.9 ± 3.0 | 11.2–12.5 | B-C, P = 0.014 | B-C, P = 0.005 | |
Average VTD | 11.9 ± 2.8 | 11.3–12.6 | |||
Normalizing parameter/mm | |||||
Manubrium length (ML) | 30.6 ± 7.4 | 28.9–32.2 | |||
Thoracic inlet-distance (Ti-D) | 54.6 ± 10.6 | 52.3–57.0 | |||
Proximal R3-width (PR3-W) | 3.7 ± 0.8 | 3.5–3.8 | |||
Manubrium-tracheal index (M-TI) | ANOVA test | Tukey’s test | Unpaired t-test | ||
M-TI (Level A) | 0.45 ± 0.07 | 0.43–0.46 | A-B, P < 0.0001 | ||
M-TI (Level B) | 0.35 ± 0.06 | 0.34–0.36 | A-C, P < 0.0001 | ||
M-TI (Level C) | 0.39 ± 0.06 | 0.38–0.40 | B-C, P ≤ 0.0001 | ||
Average M-TI | 0.40 ± 0.05 | 0.38–0.41 | |||
Thoracic inlet-tracheal index (Ti-TI) | |||||
Ti-TI (Level A) | 0.25 ± 0.04 | 0.24–0.26 | A-B, P < 0.0001 | A-B, P < 0.0001 | |
Ti-TI (Level B) | 0.19 ± 0.04 | 0.19–0.20 | P < 0.0001 | A-C, P < 0.0001 | A-C, P < 0.0001 |
Ti-TI (Level C) | 0.22 ± 0.04 | 0.21–0.23 | B-C, P = 0.0005 | B-C, P ≤ 0.0001 | |
Average Ti-TI | 0.22 ± 0.04 | 0.21–0.23 | |||
Proximal R3-tracheal score (PR3-TS) | |||||
PR3-TS (Level A) | 3.8 ± 0.7 | 3.6–4.0 | A-B, P < 0.0001 | ||
PR3-TS (Level B) | 2.9 ± 0.5 | 2.8–3.1 | A-C, P < 0.0001 | ||
PR3-TS (Level C) | 3.3 ± 0.6 | 3.2–3.4 | B-C, P = 0.0009 | ||
Average PR3-TS | 3.4 ± 0.6 | 3.2–3.5 | |||