title: Tumor microcirculation and diffusion predict therapy outcome for primary rectal carcinoma.
abstract: OBJECTIVE
  The aim of our study was to correlate perfusion indices and apparent diffusion coefficients with therapy outcome after chemoradiation.
  
  
  METHODS
  In 34 patients with primary rectal carcinoma (cT3) undergoing preoperative chemoradiation, pretherapeutic perfusion indices and apparent diffusion coefficients were obtained by dynamic or diffusion-weighted magnetic resonance imaging. Therapy response was defined if the pathologic observation revealed no invasion into the perirectal fat after chemoradiation.
  
  
  RESULTS
  In 18 patients, a response and in 16, no response was observed. Statistically significant differences were found for the mean perfusion index (p < 0.001; 7.5 +/- 1.5 mL/min/100 g vs. 10.7 +/- 2.7 mL/min/100 g) and for the intratumoral cumulative fraction of pixels with perfusion-indices > 12 mL/min/100 g (p < 0.001, 3.7 +/- 4.0% vs. 24.7 +/- 17.9%). A three-way ANOVA resulted in significant effects for therapy responder/nonresponder (p < 0.001) and for apparent diffusion coefficient and the individual patients.
  
  
  CONCLUSIONS
  Perfusion indices and apparent diffusion coefficients inside the tumor region seem to be of predictive value for therapy outcome of preoperative therapy in patients with primary rectal carcinoma. Higher parameter levels in the nonresponding group could be explained by increased shunt flow or increased angiogenic activity in aggressive tumor cell clusters resulting in reduced nutrients supply and higher fraction of intratumoral necrosis respectively.
authors.affiliation: Department of Radiotherapy and Radiooncology, Ludwig-Franzens Universität Innsbruck, Innsbruck, Austria. devries@uibk.ac.at
authors.forename: Alexander F
authors.initials: AF
authors.lastname: DeVries
authors.forename: Christian
authors.initials: C
authors.lastname: Kremser
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Hein
authors.forename: Jürgen
authors.initials: J
authors.lastname: Griebel
authors.forename: Alfons
authors.initials: A
authors.lastname: Krezcy
authors.forename: Dietmar
authors.initials: D
authors.lastname: Ofner
authors.forename: Karl Peter
authors.initials: KP
authors.lastname: Pfeiffer
authors.forename: Peter
authors.initials: P
authors.lastname: Lukas
authors.forename: Werner
authors.initials: W
authors.lastname: Judmaier
mesh_terms: D000328:Adult; D000368:Aged; D003131:Combined Modality Therapy; D017352:Echo-Planar Imaging; D006801:Humans; D008833:Microcirculation; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012004:Rectal Neoplasms / Q000098:blood supply* / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D016896:Treatment Outcome