Table 3.

Results of Spearman’s correlation tests between parotid shrinkage and imaging/ anthropometric parameters at baseline

Variable at baseline	∆Vol10fr(%)		∆Volpost(%)
	Spearman’s Rho	p-value	Spearman’s Rho	p-value
ADC	− 0.185	0.100	−0.010	0.932
Dt	−0.099	0.385	−0.061	0.609
f	−0.056	0.620	−0.002	0.986
D*	−0.019	0.865	−0.188	0.109
D* × f	−0.007	0.950	−0.167	0.154
Ktrans	0.210	0.069	0.434	< 0.001
Kep	0.239	0.038	0.349	0.003
ve	0.025	0.832	0.174	0.143
IAUGC	0.139	0.231	0.375	0.001
Parotid volume	−0.242	0.031	−0.056	0.636
Age	−0.108	0.341	0.045	0.702
Weight	−0.396	< 0.001	−0.135	0.253
BMI	−0.368	0.001	−0.127	0.281
Dmean(Gy)	0.226	0.044	−0.007	0.951
V30(%)	0.266	0.017	0.086	0.468

Statistically significant p-values are bold. Abbreviations: ∆Vol_10fr Parotid shrinkage(%) at the 10th fraction, ∆Vol_post Parotid shrinkage(%) 8 weeks after RT, ADC Apparent diffusion coefficient, D_t Tissue diffusion coefficient, D* Perfusion-related diffusion coefficient, f(%) Perfusion fraction, D* × f Product of D* by f, ∆ADC ADC variation (%) relative to the pretreatment value (analogously for the other imaging variables), K^trans Transfer constant between plasma and EES (extravascular extracellular space), K_ep Transfer constant between EES and plasma, v_e Fractional volume of EES, IAUGC Initial area under gadolinium concentration curve, BMI Body mass index, D_mean Planned mean dose to the parotid gland, V₃₀(%) Percentage of parotid volume receiving a dose ≥30 Gy