title: Role of perfusion CT in the evaluation of functional primary tumour response after radiochemotherapy in head and neck cancer: preliminary findings.
abstract: OBJECTIVE
  To report the initial results of a prospective study aimed at evaluating the CT perfusion parameter changes (∆PCTp) of the primary tumour after radiochemotherapy (RCT) in head and neck cancer (HNC) and to correlate with positron emission tomography (PET)/CT response.
  
  
  METHODS
  Eligibility criteria included HNC (Stage III-IV) candidates for RCT. Patients underwent perfusion CT (PCT) at baseline and at 3 weeks and 3 months after treatment. Blood volume, blood flow, mean transit time (MTT) and permeability surface (PS) product were computed. Moreover, PET/CT was performed at baseline and 3 months after treatment. The ∆PCTp were evaluated between baseline and 3-week/3-month evaluations, whereas PET/CT response was based on the maximum standardized uptake value changes according to the European Organization for Research and Treatment of Cancer criteria.
  
  
  RESULTS
  Between July 2012 and July 2015, 25 patients were enrolled. A significant reduction of all CT tumour perfusion parameters (PCTp) was observed from the baseline to after RCT (p < 0.001). Specifically, a significant reduction was shown at 3 weeks for all PCTp except MTT (from 6.18 to 5.14 s; p = 0.722). Differently, a significant reduction of all PCTp (p < 0.001) including MTT (from 6.18 to 2.24 s; p = 0.001) was shown at 3 months. Moreover, the reduction of PS resulted in a significant prediction of PET/CT response at 3 months (p = 0.037) with the trend also at 3 weeks (p = 0.099) at the multivariate analysis.
  
  
  CONCLUSIONS
  Our preliminary findings seem to show that almost all PCTp are significantly reduced after RCT, whereas PS seems to come out as the strongest factor in predicting the PET/CT response.
  
  
  CONCLUSIONS
  This article provides information on the potential useful role of PCT in evaluating tumour response after both early and late RCT.
authors.affiliation: 1 Department of Radiation Oncology, University Hospital S. Chiara, Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ursino
authors.affiliation: 2 Department of Radiology, University Hospital Cisanello, Pisa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Faggioni
authors.affiliation: 3 Department of Nuclear Medicine, University Hospital S.Chiara, Pisa, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Guidoccio
authors.affiliation: 1 Department of Radiation Oncology, University Hospital S. Chiara, Pisa, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ferrazza
authors.affiliation: 4 First Otorhinolaryngology Unit, University Hospital Cisanello, Pisa, Italy.
authors.forename: Veronica
authors.initials: V
authors.lastname: Seccia
authors.affiliation: 2 Department of Radiology, University Hospital Cisanello, Pisa, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Neri
authors.affiliation: 1 Department of Radiation Oncology, University Hospital S. Chiara, Pisa, Italy.
authors.forename: Luna N
authors.initials: LN
authors.lastname: Cernusco
authors.affiliation: 1 Department of Radiation Oncology, University Hospital S. Chiara, Pisa, Italy.
authors.forename: Durim
authors.initials: D
authors.lastname: Delishaj
authors.affiliation: 5 Biostatistical Consulting, Department of Oncology, University Hospital S.Chiara, Pisa, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Morganti
authors.affiliation: 3 Department of Nuclear Medicine, University Hospital S.Chiara, Pisa, Italy.
authors.forename: Duccio
authors.initials: D
authors.lastname: Volterrani
authors.affiliation: 1 Department of Radiation Oncology, University Hospital S. Chiara, Pisa, Italy.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Paiar
authors.affiliation: 2 Department of Radiology, University Hospital Cisanello, Pisa, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Caramella
mesh_terms: D001783:Blood Flow Velocity; D001810:Blood Volume / Q000502:physiology; D059248:Chemoradiotherapy / Q000379:methods*; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006258:Head and Neck Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000628:therapy*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014057:Tomography, X-Ray Computed / Q000379:methods; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D014283:Triiodobenzoic Acids; D019788:Fluorodeoxyglucose F18; C044834:iodixanol