title: Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters.
abstract: OBJECTIVE
  To compare morphological and functional MRI metrics and determine which ones perform best in assessing response to neoadjuvant chemoradiotherapy (CRT) in rectal cancer.
  
  
  METHODS
  This retrospective study included 24 uniformly-treated patients with biopsy-proven rectal adenocarcinoma who underwent MRI, including diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) sequences, before and after completion of CRT. On all MRI exams, two experienced readers independently measured longest and perpendicular tumour diameters, tumour volume, tumour regression grade (TRG) and tumour signal intensity ratio on T2-weighted imaging, as well as tumour volume and apparent diffusion coefficient on DW-MRI and tumour volume and transfer constant Ktranson DCE-MRI. These metrics were correlated with histopathological percent tumour regression in the resected specimen (%TR). Inter-reader agreement was assessed using the concordance correlation coefficient (CCC).
  
  
  RESULTS
  For both readers, post-treatment DW-MRI and DCE-MRI volumetric tumour assessments were significantly associated with %TR; DCE-MRI volumetry showed better inter-reader agreement (CCC=0.700) than DW-MRI volumetry (CCC=0.292). For one reader, mrTRG, post-treatment T2 tumour volumetry and assessments of volume change made with T2, DW-MRI and DCE-MRI were also significantly associated with %TR.
  
  
  CONCLUSIONS
  Tumour volumetry on post-treatment DCE-MRI and DW-MRI correlated well with %TR, with DCE-MRI volumetry demonstrating better inter-reader agreement.
  
  
  CONCLUSIONS
  • Volumetry on post-treatment DCE-/DW-MRI sequences correlated well with histopathological tumour regression. • DCE-MRI volumetry demonstrated good inter-reader agreement. • Inter-reader agreement was higher for DCE-MRI volumetry than for DW-MRI volumetry. • DCE-MRI volumetry merits further investigation as a metric for evaluating treatment response.
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA. Andreas.Hoetker@uni-mainz.de.|Department of Diagnostic and Interventional Radiology, Universitätsmedizin Mainz, Langenbeckstr. 1, 55131, Mainz, Germany. Andreas.Hoetker@uni-mainz.de.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Hötker
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Tarlinton
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Yousef
authors.initials: Y
authors.lastname: Mazaheri
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Kaitlin M
authors.initials: KM
authors.lastname: Woo
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Mithat
authors.initials: M
authors.lastname: Gönen
authors.affiliation: Department of Medicine, Gastrointestinal Oncology Service, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Saltz
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Karyn A
authors.initials: KA
authors.lastname: Goodman
authors.affiliation: Department of Surgery, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia-Aguilar
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Gollub
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059186:Chemoradiotherapy, Adjuvant / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Diffusion MRI; Dynamic contrast-enhanced MRI; Magnetic resonance imaging; Neoadjuvant treatment; Rectal cancer