Dynamic contrast-enhanced and diffusion-weighted MRI for early detection of tumoral changes in single-dose and fractionated radiotherapy: evaluation in a rat rhabdomyosarcoma model.
We aimed to examine different intratumoral changes after single-dose and fractionated radiotherapy, using diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in a rat rhabdomyosarcoma model. Four WAG/Rij rats with rhabdomyosarcomas in the flanks received single-dose radiotherapy of 8 Gy, and four others underwent fractionated radiotherapy (five times 3 Gy). In rats receiving single-dose radiotherapy, a significant perfusion decrease was found in the first 2 days post-treatment, with slow recuperation afterwards. No substantial diffusion changes could be seen; tumor growth delay was 12 days. The rats undergoing fractionated radiotherapy showed a similar perfusion decrease early after the treatment. However, a very strong increase in apparent diffusion coefficient occurred in the first 10 days; growth delay was 18 days. DW-MRI and DCE-MRI can be used to show early tumoral changes induced by radiotherapy. Single-dose and fractionated radiotherapy induce an immediate perfusion effect, while the latter induces more intratumoral necrosis.
De Keyzer
F
F
Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium. Frederik.DeKeyzer@uz.kuleuven.be
Vandecaveye
V
V
Thoeny
H
H
Chen
F
F
Ni
Y
Y
Marchal
G
G
Hermans
R
R
Nuyts
S
S
Landuyt
W
W
Bosmans
H
H
D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000494:pharmacology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004195:Disease Models, Animal; D019583:Dose Fractionation, Radiation; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009336:Necrosis; D009368:Neoplasm Transplantation; D010477:Perfusion; D011878:Radiotherapy / Q000379:methods*; D051381:Rats; D012208:Rhabdomyosarcoma / Q000473:pathology / Q000532:radiotherapy*
D003287:Contrast Media