title: Value of gadofosveset-enhanced MRI and multiplanar reformatting for selecting good responders after chemoradiation for rectal cancer.
abstract: OBJECTIVE
  Our primary objective was to evaluate diagnostic performance of gadofosveset T1-weighted magnetic resonance imaging (T1W MRI) for discriminating between ypT0-2 and ypT3-4 tumours after chemoradiation therapy (CRT) for rectal cancer compared with T2W MRI for a general and expert reader. Second objectives included assessing the value of multiplanar reformatting (MPR) and interobserver agreement.
  
  
  METHODS
  A general and expert reader evaluated 49 patients for likelihood of ypT0-2 tumour after CRT on T2W, gadofosveset T1W MRI, and gadofosveset T1W MRI + T2W MRI. The general reader scored with and without MPR. Confidence level scores were used to construct receiver-operating characteristic (ROC) curves. Area under the curve (AUC) values and diagnostic parameters were calculated and compared.
  
  
  RESULTS
  Gadofosveset T1W MRI + T2W MRI showed slightly superior sensitivity than T2W MRI for the general but not the expert reader. Specificity was higher for the expert on gadofosveset T1W MRI only compared with T2W MRI only (100% vs. 82%). MPR did not increase diagnostic performance. Interobserver agreement was highest for the combination of gadofosveset-enhanced T1W imaging plus T2W MRI.
  
  
  CONCLUSIONS
  The sole use or addition of gadofosveset-enhanced T1W MRI to T2W MRI did not increase significantly diagnostic performance for assessing ypT0-2 tumours. Adding gadofosveset-enhanced T1W MRI slightly increased sensitivity for the general reader and specificity for the expert reader, but this increase was not significant for more accurate clinical decision making. MPR did not improve diagnostic performance.
  
  
  CONCLUSIONS
  • ycT restaging with MRI in rectal cancer is challenging. • Gadofosveset-enhanced T1W MRI has shown promise for nodal restaging. • Gadofosveset-enhanced T1W MRI did not significantly increase diagnostic performance for assessing ypT0-2-tumours. • Addition of the gadofosveset sequence to T2W MRI slightly increased sensitivity for the general reader. • MPR did not improve diagnostic performance of ycT staging.
authors.affiliation: Department of Radiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Luc A
authors.initials: LA
authors.lastname: Heijnen
authors.forename: Monique
authors.initials: M
authors.lastname: Maas
authors.forename: Max J
authors.initials: MJ
authors.lastname: Lahaye
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lalji
authors.forename: Doenja M J
authors.initials: DM
authors.lastname: Lambregts
authors.forename: Milou H
authors.initials: MH
authors.lastname: Martens
authors.forename: Robert G
authors.initials: RG
authors.lastname: Riedl
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.forename: Regina G H
authors.initials: RG
authors.lastname: Beets-Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009942:Organometallic Compounds; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium