title: FDG PET/CT and diffusion-weighted imaging of head and neck squamous cell carcinoma: comparison of prognostic significance between primary tumor standardized uptake value and apparent diffusion coefficient.
abstract: OBJECTIVE
  To compare primary tumor (18)F-fluorodeoxyglucose (FDG) maximum standardized uptake value (SUV(max)) and diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) obtained in the same patients with head and neck squamous cell carcinoma (HNSCC) to clarify the prognostic significance of both indexes.
  
  
  METHODS
  The study population comprised 26 patients with HNSCC visible on both pretreatment FDG PET/CT and DWI. Correlation between SUV(max) and ADC (b values; 0 and 800 seconds/mm(2)) was analyzed by the Spearman's rank test. Disease-free survival (DFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by the long-rank test and Cox proportional hazards analysis.
  
  
  RESULTS
  SUV(max) and ADC correlated significantly and negatively (ρ = -0.566, P = 0.005). High (>12.1) SUV(max) (P < 0.001), low (≤ 0.88) ADC (P = 0.009), high (T3-4) T stage (P = 0.030), and high (N2-3) N stage (P = 0.007) were significant in predicting poor 2-year DFS. The accuracy for predicting disease events was 81% (21/26) for SUV(max) (>12.1) and 73% (19/26) for ADC(≤ 0.88) without significant difference between them (P = 0.52). Disease event hazards ratios for significant unadjusted SUV(max) (P = 0.015) and ADC (P = 0.039) remained significant when adjusted for other dichotomized clinical covariates (SUV(max); P = 0.009-0.039, ADC; P = 0.017-0.037) except SUV(max) for ADC and ADC for SUV(max) and T stage.
  
  
  CONCLUSIONS
  These results suggest that pretreatment primary tumor SUV(max) and ADC correlate significantly and negatively and both may have similar potential to predict DFS or disease events of HNSCC.
authors.affiliation: Department of Radiology, Field of Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. toyo.nakajo@dolphin.ocn.ne.jp
authors.forename: Masatoyo
authors.initials: M
authors.lastname: Nakajo
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakajo
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Kajiya
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tani
authors.forename: Takuro
authors.initials: T
authors.lastname: Kamiyama
authors.forename: Ryuji
authors.initials: R
authors.lastname: Yonekura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Fukukura
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Matsuzaki
authors.forename: Kengo
authors.initials: K
authors.lastname: Nishimoto
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Nomoto
authors.forename: Chihaya
authors.initials: C
authors.lastname: Koriyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011379:Prognosis; D016016:Proportional Hazards Models; D000077195:Squamous Cell Carcinoma of Head and Neck; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18