title: Feasibility analysis of the parametric response map as an early predictor of treatment efficacy in head and neck cancer.
abstract: OBJECTIVE
  Estimating changes in the volume transfer constant, normalized area under the contrast-enhancement time curve at 60 seconds, and fractional blood plasma volume by using dynamic contrast-enhanced MR imaging may be useful in predicting tumor response to chemoradiation. We hypothesized that the parametric response map, a voxel-by-voxel analysis of quantitative dynamic contrast-enhanced MR imaging maps, predicts survival in patients with head and neck cancer.
  
  
  METHODS
  Ten patients with locoregionally advanced head and neck squamous cell carcinoma underwent definitive concurrent chemoradiation therapy. For each patient, dynamic contrast-enhanced MR imaging data were collected before and 2 weeks after treatment initiation. Change in perfusion parameters within the primary tumor volume with time was analyzed by parametric response mapping and by whole-tumor mean percentage change. Outcome was defined as overall survival. The perfusion parameter and metric most predictive of outcome were identified. Overall survival was estimated by the log-rank test and Kaplan-Meier survival curve.
  
  
  RESULTS
  The volume transfer constant and normalized area under the contrast-enhancement time curve at 60 seconds were predictive of survival both in parametric response map analysis (volume transfer constant, P = .002; normalized area under the contrast-enhancement time curve at 60 seconds, P = .02) and in the percentage change analysis (volume transfer constant, P = .04; normalized area under the contrast-enhancement time curve at 60 seconds, P = .02). Blood plasma volume predicted survival in neither analysis.
  
  
  CONCLUSIONS
  Parametric response mapping of MR perfusion biomarkers could potentially guide treatment modification in patients with predicted treatment failure. Larger studies are needed to determine whether parametric response map analysis or percentage signal change in these perfusion parameters is the stronger predictor of survival.
authors: From the Department of Radiology (A.H.B., B.A.H., A.S., C.J.G.), University of Michigan Health System, Ann Arbor, Michigan aaronbaer@gmail.com.
authors: A H
authors: AH
authors: Baer
authors: From the Department of Radiology (A.H.B., B.A.H., A.S., C.J.G.), University of Michigan Health System, Ann Arbor, Michigan.
authors: B A
authors: BA
authors: Hoff
authors: From the Department of Radiology (A.H.B., B.A.H., A.S., C.J.G.), University of Michigan Health System, Ann Arbor, Michigan.
authors: A
authors: A
authors: Srinivasan
authors: From the Department of Radiology (A.H.B., B.A.H., A.S., C.J.G.), University of Michigan Health System, Ann Arbor, Michigan.
authors: C J
authors: CJ
authors: Galbán
authors: Department of Radiology (S.K.M.), Michigan State University, East Lansing, Michigan.
authors: S K
authors: SK
authors: Mukherji
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D059248:Chemoradiotherapy; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D000077195:Squamous Cell Carcinoma of Head and Neck; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media