title: Simple measurements on diffusion-weighted MR imaging for assessment of complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer.
abstract: OBJECTIVE
  To determine diagnostic performance of simple measurements on diffusion-weighted MR imaging (DWI) for assessment of complete tumour response (CR) after neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC) by signal intensity (SI) and apparent diffusion coefficient (ADC) measurements.
  
  
  METHODS
  Sixty-five patients with LARC who underwent neoadjuvant CRT and subsequent surgery were included. Patients underwent pre-CRT and post-CRT 3.0 T MRI. Regions of interest of the highest brightness SI were included in the tumour volume on post-CRT DWI to calculate the SIlesion, rSI, ADClesion and rADC; diagnostic performance was compared by using the receiver operating characteristic (ROC) curves. In order to validate the accuracy and reproducibility of the current strategy, the same procedure was reproduced in 80 patients with LARC at 1.5 T MRI.
  
  
  RESULTS
  Areas under the ROC curve for identification of a CR, based on SIlesion, rSI, ADClesion, and rADC, respectively, were 0.86, 0.94, 0.66, and 0.71 at 3.0 T MRI, and 0.92, 0.91, 0.64, and 0.61 at 1.5 T MRI.
  
  
  CONCLUSIONS
  Post-CRT DWI SIlesion and rSI provided high diagnostic performance in assessing CR and were significantly more accurate than ADClesion, and rADC at 3.0 T MRI and 1.5 T MRI.
  
  
  CONCLUSIONS
  • Signal intensity (SI lesion ) and rSI are accurate for assessment of complete response. • rSI seems to be superior to SI lesion at 3.0 T MRI. • ADC or rADC measurements are not accurate for assessment of complete response.
authors.affiliation: State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, Peoples Republic of China, caipq@sysucc.org.cn.
authors.forename: Pei-Qiang
authors.initials: PQ
authors.lastname: Cai
authors.forename: Yao-Pan
authors.initials: YP
authors.lastname: Wu
authors.forename: Xin
authors.initials: X
authors.lastname: An
authors.forename: Xue
authors.initials: X
authors.lastname: Qiu
authors.forename: Ling-Heng
authors.initials: LH
authors.lastname: Kong
authors.forename: Guo-Chen
authors.initials: GC
authors.lastname: Liu
authors.forename: Chuan-Miao
authors.initials: CM
authors.lastname: Xie
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Pan
authors.forename: Pei-Hong
authors.initials: PH
authors.lastname: Wu
authors.forename: Pei-Rong
authors.initials: PR
authors.lastname: Ding
mesh_terms: D000328:Adult; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy; D015203:Reproducibility of Results; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult