title: Perfusion MRI for the prediction of treatment response after preoperative chemoradiotherapy in locally advanced rectal cancer.
abstract: OBJECTIVE
  To evaluate the utility of perfusion MRI as a potential biomarker for predicting response to chemoradiotherapy (CRT) in locally advanced rectal cancer.
  
  
  METHODS
  Thirty-nine patients with primary rectal carcinoma who were scheduled for preoperative CRT were prospectively recruited. Perfusion MRI was performed with a 3.0-T MRI system in all patients before therapy, at the end of the 2nd week of therapy, and before surgery. The K (trans) (volume transfer constant) and V (e) (extracellular extravascular space fraction) were calculated.
  
  
  RESULTS
  Before CRT, the mean tumour K (trans) in the downstaged group was significantly higher than that in the non-downstaged group (P = 0.0178), but there was no significant difference between tumour regression grade (TRG) responders and TRG non-responders (P = 0.1392). Repeated-measures analysis of variance (ANOVA) showed significant differences for evolution of K (trans) values both between downstaged and non-downstaged groups (P = 0.0215) and between TRG responders and TRG non-responders (P = 0.0001). Regarding V (e), no significant differences were observed both between downstaged and non-downstaged groups (P = 0.689) or between TRG responders and TRG non-responders (P = 0.887).
  
  
  CONCLUSIONS
  Perfusion MRI of rectal cancer can be useful for assessing tumoural K (trans) changes by CRT. Tumours with high pre-CRT K (trans) values tended to respond favourably to CRT, particularly in terms of downstaging criteria.
  
  
  CONCLUSIONS
  • Perfusion MRI can now assess therapeutic response of tumours to therapy. • Tumours with high initial K ( trans ) values responded favourably to chemoradiotherapy. • Perfusion MRI of rectal cancer may help with decisions about management.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Joon Seok
authors.initials: JS
authors.lastname: Lim
authors.forename: Daehong
authors.initials: D
authors.lastname: Kim
authors.forename: Song-Ee
authors.initials: SE
authors.lastname: Baek
authors.forename: Sungmin
authors.initials: S
authors.lastname: Myoung
authors.forename: Junjeong
authors.initials: J
authors.lastname: Choi
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Shin
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
authors.forename: Jinsuk
authors.initials: J
authors.lastname: Suh
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Keum
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002277:Carcinoma / Q000473:pathology* / Q000628:therapy*; D059248:Chemoradiotherapy / Q000379:methods*; D003131:Combined Modality Therapy / Q000379:methods; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D010539:Permeability; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D003287:Contrast Media