title: Neuroendocrine tumor liver metastases: use of dynamic contrast-enhanced MR imaging to monitor and predict radiolabeled octreotide therapy response.
abstract: OBJECTIVE
  To evaluate dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for monitoring and assessing treatment response in patients with neuroendocrine liver metastases treated using yttrium 90 ((90)Y)-labeled octreotide ((90)Y-DOTATOC).
  
  
  METHODS
  The study was approved by the local research and ethics committee and patient informed consent was obtained. Twenty patients with liver metastases from neuroendocrine tumors underwent T1-weighted DCE MR imaging of the liver before and at 2 months after intravenous (90)Y-DOTATOC treatment. Regions of interest were drawn around target lesions, as well as along liver outlines for each patient. A dual-input single-compartment model was used to compute parameters including fractional distribution volume and the arterial flow fraction. Pre- and posttreatment values were compared using Wilcoxon signed rank test. Treatment response was defined as showing a greater than 50% reduction in the nadir chromogranin A level within the 1st year after treatment. Pretreatment values of responders and nonresponders were compared using the Mann-Whitney test. A two-tailed P value of .008 or less, which accounts for multiple testing, was considered to indicate a significant difference.
  
  
  RESULTS
  In responders, tumor and whole liver distribution volume significantly increased after treatment (median tumor distribution volume, 0.182 vs 0.244; median whole liver distribution volume, 0.175 vs 0.207; P = .008). The pretreatment whole liver distribution volume was significantly lower in responders (median, 0.175 vs 0.248; P = .003), while pretreatment tumor arterial flow fraction was significantly higher in responders (median, 1.000 vs 0.7 ± 1, P = .006).
  
  
  CONCLUSIONS
  DCE MR imaging may be used to monitor the effects of peptide receptor radiolabeled targeted therapy in patients with neuroendocrine tumors liver metastases; a lower pretreatment distribution volume and high arterial flow fraction was associated with a better response to treatment.
authors.affiliation: Institute of Cancer Research, Cancer Research UK and EPSRC Cancer Imaging Centre, Sutton, Surrey SM2 5NG, England. Keiko.Miyazaki@icr.ac.uk
authors.forename: Keiko
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Orton
authors.forename: Robert L
authors.initials: RL
authors.lastname: Davidson
authors.forename: James A
authors.initials: JA
authors.lastname: d'Arcy
authors.forename: Valerie
authors.initials: V
authors.lastname: Lewington
authors.forename: Tong San
authors.initials: TS
authors.lastname: Koh
authors.forename: Choon Hua
authors.initials: CH
authors.lastname: Thng
authors.forename: Martin O
authors.initials: MO
authors.lastname: Leach
authors.forename: David J
authors.initials: DJ
authors.lastname: Collins
authors.forename: Dow-Mu
authors.initials: DM
authors.lastname: Koh
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D003287:Contrast Media; D016002:Discriminant Analysis; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000473:pathology*; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D015996:Survival Rate; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019786:Gadolinium DTPA; D015282:Octreotide; C106246:Edotreotide