title: Tumor volume and subvolume concordance between FDG-PET/CT and diffusion-weighted MRI for squamous cell carcinoma of the cervix.
abstract: OBJECTIVE
  To compare [(18)F]fluorodeoxyglucose (FDG)/positron emission tomography (PET)/computed tomography (CT) and magnetic resonance imaging (MRI) for evaluating patients with cervical cancer. We compared tumor characteristics on FDG-PET and apparent diffusion coefficient (ADC) maps on diffusion-weighted MRI (DWI) to evaluate concordance of two functional imaging techniques.
  
  
  METHODS
  Twenty women with cervical cancer underwent pretreatment FDG-PET/CT and pelvic MRI. Images were rigidly fused by pelvic anatomy using coregistration software. Tumor contours on PET images were generated by autosegmentation of the region containing at least 40% of the maximum standardized uptake value (SUV). DWI contours were generated by manual segmentation. Tumor volume similarity was evaluated using the [PET]/[ADC] volume proportion, Dice's coefficient, and the mean SUV isothreshold at the surface of each ADC contour. Tumor subvolume similarity was evaluated with analysis of variance (ANOVA).
  
  
  RESULTS
  The [PET]/[ADC] volume proportion was 0.88 ± 0.14. Dice's coefficient between PET and ADC tumor contours was 0.76 ± 0.06. The mean SUV isothreshold at the ADC-delineated tumor surface was 34 ± 4%. Subvolumes with increased metabolic activity on FDG-PET also had more restricted diffusion on DWI (P < 0.0001, ANOVA).
  
  
  CONCLUSIONS
  Concordance of functional imaging was observed between FDG-PET and DWI for cervical cancer. Tumor subvolumes with increased metabolic activity on FDG-PET also have greater cell density by DWI.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Olsen
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Esthappan
authors.forename: Todd
authors.initials: T
authors.lastname: DeWees
authors.forename: Vamsi R
authors.initials: VR
authors.lastname: Narra
authors.forename: Farrokh
authors.initials: F
authors.lastname: Dehdashti
authors.forename: Barry A
authors.initials: BA
authors.lastname: Siegel
authors.forename: Julie K
authors.initials: JK
authors.lastname: Schwarz
authors.forename: Perry W
authors.initials: PW
authors.lastname: Grigsby
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18