title: Diffusion-weighted magnetic resonance imaging for monitoring diffusion changes in rectal carcinoma during combined, preoperative chemoradiation: preliminary results of a prospective study.
abstract: 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.
authors.affiliation: Department of Radiotherapy and Radiooncology, University of Innsbruck, Innsbruck, Austria. patrick.a.hein@hitchcock.org
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Hein
authors.forename: Christian
authors.initials: C
authors.lastname: Kremser
authors.forename: Werner
authors.initials: W
authors.lastname: Judmaier
authors.forename: Jürgen
authors.initials: J
authors.lastname: Griebel
authors.forename: Karl-Peter
authors.initials: KP
authors.lastname: Pfeiffer
authors.forename: Alfons
authors.initials: A
authors.lastname: Kreczy
authors.forename: Eugen B
authors.initials: EB
authors.lastname: Hug
authors.forename: Peter
authors.initials: P
authors.lastname: Lukas
authors.forename: Alexander F
authors.initials: AF
authors.lastname: DeVries
mesh_terms: 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