Table 3.
Correlations between atrophy rate and the change rates of parotid IVIM or DCE MR parameters
| Atrophy rate | r | p value |
|---|---|---|
| RIVIM-PARs | ||
| RADC | −0.418 | 0.011a |
| RD | 0.066 | 0.702 |
| RD* | 0.038 | 0.825 |
| Rf | −0.449 | 0.006a |
| RDCE-PARs | ||
| RMRE | −0.372 | 0.025a |
| RTTP | 0.208 | 0.223 |
| RWash in Rate | −0.136 | 0.428 |
IVIM Intravoxel incoherent motion, DCE Dynamic contrast-enhanced, r Pearson correlation coefficient, R IVIM-PARs and R DCE-PARs are the change rates of IVIM and DCE MR parameters from pre-RT to post-RT, respectively, R ADC, R D, R D*, R f, R MRE, R TTP and R Wash in Rate are the change rates of apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), maximum relative enhancement (MRE), time to peak (TTP) and Wash in Rate from pre-RT (2 weeks before radiotherapy) to post-RT (4 weeks after RT), respectively
adenotes a significant correlation between the parotid atrophy rate and the change rate of each IVIM or DCE MR parameter