. Author manuscript; available in PMC: 2011 Dec 1.

Published in final edited form as: Acad Radiol. 2010 Oct 14;17(12):1525–1534. doi: 10.1016/j.acra.2010.08.005

Table 1.

Calculated and measured airway tube cross-sectional dimensions.

Tube	Tilt^*	ID^* (mm)	OD^* (mm)	Pi (mm)			WT (mm)			WA (mm²)			WA% (%)
				Ref. Val.^**	Mean	StdDev	Ref. Val.^**	Mean	StdDev	Ref. Val.^**	Mean	StdDev	Ref. Val.^**
1t	30	3.0	4.2	9.42	8.35	0.25	0.60	1.17	0.06	6.79	14.12	0.57	48.98
1		3.0	4.2	9.42	7.95	0.06	0.60	1.05	0.01	6.79	11.82	0.12	48.98
2		6.0	7.8	18.85	18.66	0.04	0.90	1.02	0.01	19.51	22.20	0.33	40.83
3t	30	6.0	8.4	18.85	20.22	0.15	1.20	1.34	0.07	27.14	32.70	1.81	48.98
3		6.0	8.4	18.85	19.19	0.04	1.20	1.11	0.00	27.14	25.27	0.07	48.98
4		6.0	9.0	18.85	19.19	0.82	1.50	1.30	0.12	35.34	29.67	1.19	55.56

Inner Diameter (ID) and Outer Diameter (OD) were listed in the manufacturer's manual (The Phantom Laboratory, Inc, “CTP657 Lung Phantom Manual”, Salem, NY, 2008.).

^**

Inner Perimeter (Pi) = π ID; wall thickness (WT) = [(OD-ID)/2]; wall area (WA) = [π(OD/2)² - π(ID/2)²]; wall area percent (WA%) = [WA/π(OD/2)² × 100%]

Note - Measurements were made using the phase congruency method over seven consecutive slices.