Texture analysis on parametric maps derived from dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer

Table 2 Paired student’s t test on tumor volume, Ktrans and ve between pretreatment and intra-treatment scans (n = 19)

Parameters	Measures	Pre (n = 19) (mean ± SD)	Intra (n = 19) (mean ± SD)	P values
Tumor volume (cm3)		9.02 ± 6.87	7.23 ± 6.22	0.02a
Ktrans (volume transfer rate, min-1)	Mean	0.34 ± 0.18	0.37 ± 0.22	0.36
	SD	0.25 ± 0.11	0.25 ± 0.11	0.99
	E	0.34 ± 0.14	0.38 ± 0.19	0.18
	H	0.84 ± 0.04	0.83 ± 0.05	0.61
ve (volume fraction of the extravascular extracellular space)	Mean	0.29 ± 0.12	0.34 ± 0.19	0.09
	SD	0.15 ± 0.04	0.17 ± 0.07	0.26
	E	0.30 ± 0.11	0.41 ± 0.22	0.041
	H	0.84 ± 0.04	0.83 ± 0.06	0.78

¹P < 0.05 of comparison Pre vs Intra. SD: Standard deviation; E: Energy; H: Homogeneity; Pre: Pretreatment; Intra: Intra-treatment.