Diffusion-weighted magnetic resonance imaging for monitoring diffusion changes in rectal carcinoma during combined, preoperative chemoradiation: preliminary results of a prospective study.
OBJECTIVE
To evaluate the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) to monitor response of primary carcinoma of the rectum to preoperative chemoradiation by measuring tumor apparent diffusion coefficient (ADC).


METHODS
Diffusion data of nine patients undergoing preoperative combined chemoradiation for clinical staged T3, N(0-2), M(0) carcinoma of the rectum were analyzed. Diffusion-weighted echo-planar MR images were obtained prior to and at specified intervals during chemoradiation and ADCs calculated from acquired tumor images.


RESULTS
Comparison of mean ADC and cumulative radiation dose showed a significant decrease of mean ADC at the 2nd (P = 0.028), 3rd (P = 0.012), and 4th (P = 0.008) weeks of treatment. Cytotoxic edema and fibrosis were considered as reasons for ADC decrease.


CONCLUSIONS
This study demonstrated tumor ADC changes via detection of therapy-induced alterations in tumor water mobility. Our results indicate that diffusion-weighted imaging may be a valuable clinical tool to diagnose the early stage of radiation-induced fibrosis.
Hein
Patrick A
PA
Department of Radiotherapy and Radiooncology, University of Innsbruck, Innsbruck, Austria. patrick.a.hein@hitchcock.org
Kremser
Christian
C
Judmaier
Werner
W
Griebel
Jürgen
J
Pfeiffer
Karl-Peter
KP
Kreczy
Alfons
A
Hug
Eugen B
EB
Lukas
Peter
P
DeVries
Alexander F
AF
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery / Q000628:therapy; D000328:Adult; D000368:Aged; D017024:Chemotherapy, Adjuvant; D038524:Diffusion Magnetic Resonance Imaging; D019583:Dose Fractionation, Radiation; D017352:Echo-Planar Imaging; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery / Q000628:therapy