Table 3—

Power law regression equations for computed tomography estimated airway and arterial areasversus subject height

Y variable^#	Subjects n	Sex	A	B	Correlation R²	p-value
Lumen area cm²
Trachea	48	Both	0.0003	1.64	0.90	<0.001
RBI	34	Both	0.0003	1.46	0.85	<0.001
RAB	29	Both	2×10⁻⁶	2.02	0.80	<0.001
First branch after RAB	29	Both	3×10⁻⁶	1.69	0.75	<0.001
Second branch after RAB	25	Both	5×10⁻⁷	1.94	0.77	<0.001
Wall area cm²
Trachea	48	Both	0.0016	1.27	0.87	<0.001
RBI	34	Both	0.0024	1.10	0.86	<0.001
RAB	29	Both	0.0004	1.30	0.80	<0.001
First branch after RAB	29	Both	0.0005	1.13	0.83	<0.001
Second branch after RAB	25	Both	5×10⁻⁵	1.41	0.85	<0.001
Arterial area cm²
RAB	31	Both	0.0004	1.21	0.76	<0.001
First branch after RAB	30	Both	5.6×10⁻⁵	1.53	0.73	<0.001
Second branch after RAB	46	Both	1.9×10⁻⁵	1.62	0.77	<0.001
Third branch after RAB	47	Both	4.5×10⁻⁶	1.78	0.86	<0.001

Y: the airway or artery variable (lumen, wall or artery area); A: the Y intercept; B: the slope (power law exponent) of the regression; RBI: right bronchus intermedius; RAB: right apical bronchus. ^#: Y = A × subject height in cm.