title: Assessment of pathological complete response to preoperative chemoradiotherapy by means of multiple mathematical models of diffusion-weighted MRI in locally advanced rectal cancer: A prospective single-center study.
abstract: To assess stretched-exponential, mono-exponential and intravoxel incoherent motion (IVIM) models of diffusion-weighted MRI(DWI) in predicting pathological complete response (pCR) to neoadjuvant chemoradiotherapy (CRT) in rectal cancer patients.
  
  
  
  This prospective study recruited 98 consecutive patients with locally advanced rectal cancer who underwent 3 Tesla MR examination before, during and after CRT. The apparent diffusion coefficient (ADC), IVIM-derived parameters (D, f, and D*), and stretched-exponential model-derived parameters (DDC and α) were measured. The parameters and their corresponding changes during and after CRT were compared between pCR and non-pCR. Receiver-operating characteristic curve analysis was performed to evaluate the diagnostic performance. Coefficient of variations and intraclass correlation coefficient were calculated to assess reliability and agreement.
  
  
  
  Nineteen patients achieved pCR while 79 did not. The pCR group had higher ADC and α (ADC2and α2), and their changes (ΔADC2, and Δα2) at the endpoint than non-pCR group. α2and ADC2yielded similar AUCs (P = 0.339), Δα2and ΔADC2yielded similar AUCs (P = 0.263) ADC and α presented substantial agreement, and α presented the minimum CV (5.0-7.0%).
  
  
  
  ADC and α were useful for assessing pCR after CRT. α might be more useful because it demonstrated better diagnostic performance than IVIM-derived parameters and better reliability than ADC.
  
  
  
  1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:175-183.
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Hai-Bin
authors.initials: HB
authors.lastname: Zhu
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: Center for Magnetic Research, Medical Hospital, University of Illinois Hospital, Chicago, Illinois, USA.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Zhou
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Xiao-Ting
authors.initials: XT
authors.lastname: Li
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Yu-Liang
authors.initials: YL
authors.lastname: Liu
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University Cancer Hospital & Institute, No. 52, Beijing, China.
authors.forename: Ying-Shi
authors.initials: YS
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D017063:Outcome Assessment, Health Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods*; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
keywords: diffusion-weighted magnetic resonance imaging; pathological complete response; rectal cancer; stretched-exponential model