Table 2.

Densitometric progression ('raw' data)

Mean ± SD	Baseline	Follow-up	Change from baseline	t	p value	Annual change
WL Perc15 (HU)	-939.09 ± 33.44	-946.16 ± 29.26	-7.06 ± 8.97	-6.64	< 0.0001	-3.53
WL VI-950 (%)	15.08 ± 10.63	17.75 ± 11.35	2.67 ± 3.34	6.74	< 0.0001	1.34
WL VI-910 (%)	36.29 ± 18.28	40.48 ± 18.06	4.18 ± 5.14	6.86	< 0.0001	2.09

WL, whole lung; Perc15,15^th percentile point (measured in Hounsfield Units); SD, standard deviation; VI-950, voxel index at a threshold of -950HU (measured in %); VI-910, voxel index at a threshold of -910HU (measured in %); annual change, change in outcome measure without adjustment for lung volume.