Table 4.
Changes in DWI/IVIM parameters during and after radiotherapy compared to baseline values in salivary glands.
| Author, year | OAR | Time point | Main findings |
|---|---|---|---|
| Zhang, 2018 [10] | PG, SMG | BL 2w after RT-start |
ADC sign. increased during RT in both, PGs (median ADC +44%) and SMGs (+27%). ADC sign. decreased during RT in the PGs (−25%) and non-significantly in the SMGs (-13%), same for the difference between ADC after stimulation and ADC at rest (PGs: −42%, sign., SMGs: −24%, n.s.). ΔADC at rest and after stimulation of the PGs sign. correlated with degree of xerostomia 6 months post-RT (r = 0.41/−0.61/−0.72), whereas ΔADC of the SMGs did not. |
| Loimu, 2017 [13] | PG, SMG | BL 6m post-RT |
PGs with sign. higher ADC values than SMGs. ADC sign. increased from BL to post-RT for both, PGs (+29%) and SMGs (+28%). ADC after stimulation sign. higher post-RT than at BL. Sign. linear correlation between change of ADC from BL to post-RT with dose for both, PGs and SMGs. |
| Marzi, 2015 [17] | PG | BL fx16-17 Last fx |
Sign. increase in all diffusion parameters, ADC (+15%/+21%), ADClow, D and f, from baseline to mid- and post-treatment, respectively. D only diffusion parameter with sign. correlation to PG dose. |
| Juan, 2015 [18] | PG | BL Mean 7w post-RT Mean 8m post-RT Mean 16m post-RT |
ADC increased by 36% (post-RT TP 1, sign.), 27% (post-RT TP 2, sign.) and 20% (post-RT TP 3, sign.). ADC with sign. neg. correlation to PG volume and sign. pos. correlation to dose. Patients with G1/2 xerostomia with sign. higher ADC. |
| Doornaert, 2014 [19] | PG, SMG | BL, 20–22 Gy, 2–3 m post-RT |
SMGs with higher ADC values than PGs. Increase in ADC from BL to mid-RT (EPI DWI: +18%/HASTE DWI: 9%) and further increase to post-RT (+39%/+44%). |
| Zhang, 2013 [20] | PG | BL Within 2w post-RT |
ADC (+44%) and increase of ADC after stimulation sign. increased post-RT. |
| Dirix, 2008 [27] | PG, SMG | BL Mean 9m post-RT |
PGs with sign. higher ADC values than SMGs. Ipsilateral PGs with sign. increased ADC and no response to stimulation post-RT compared to BL. Contralateral PGs with no sign. change in ADC from BL to post-RT and similar response to stimulation (initial decrease followed by increase) post-RT. Both SGs with sign. increase of ADC post-RT, but only contralateral SGs with similar response to stimulation compared to BL. |
ADC: apparent diffusion coefficient, ADClow: ADC derived by low b-values, BL: baseline, D: true diffusion, EPI: echo planar imaging, f: perfusion fraction, HASTE: half-fourier acquisition single-shot turno spin-echo, m: months, n.s.: not significant, OAR: organ at risk, PG: parotid gland, RT: radiotherapy, SG: salivary gland, sign.: significant/ly, SMG: submandibular gland, TP: time point, w: week.