title: Combined measurement of tumor perfusion and glucose metabolism for improved tumor characterization in advanced cervical carcinoma. A PET/CT pilot study using [15O]water and [18F]fluorodeoxyglucose.
abstract: OBJECTIVE
  The aim of this pilot study was (1) to evaluate the combination of [(18)F]fluorodeoxyglucose (FDG) and [(15)O]water for detection of flow-metabolism mismatch in advanced cervical carcinomas, i.e., increased glycolysis at low blood flow, as a possible parameter for prediction of response to treatment, and (2) to propose a method for automated quantification of its spatial extent.
  
  
  METHODS
  The study retrospectively included 10 women with advanced cervical carcinoma in whom PET with both FDG and [(15)O]water had been performed prior to therapy. The metabolically active tumor volume was delineated automatically in the FDG images. For computation of the regional blood flow in the tumor, a recovery corrected image-derived arterial input function was used. A tumor voxel was classified as mismatched when the voxel SUV of FDG was larger than the median tumor SUV and the voxel perfusion (K1) was smaller than the median perfusion. The absolute mismatch volume (aMMV) was defined as the volume of all mismatched voxels in ml, and the relative mismatch volume (rMMV) as the ratio of the aMMV to the metabolic tumor volume in percent.
  
  
  RESULTS
  The tumors were quite heterogeneous with respect to both FDG uptake and perfusion. The aMMV clustered into 2 groups: "large aMMV" ≥ 10 ml in 40 % of patients and "small aMMV" ≤ 5 ml in 60 % of patients. The rMMV ranged from 12.7-24.9 %. There was no correlation between rMMV and metabolic tumor volume. There was a tendency (p = 0.126) for an association between rMMV and histological grading, rMMV being about 20 % higher in G3 than in G2 tumors. rMMV did not correlate with SUV or perfusion.
  
  
  CONCLUSIONS
  These results suggest that combined PET with FDG and [(15)O]water allows detection and quantitative characterization of flow-metabolism mismatch in advanced cervical carcinomas.
authors.affiliation: Department of Nuclear Medicine, Charité University Medical Center, Berlin, Germany, ivayla.apostolova@med.ovgu.de.
authors.forename: I
authors.initials: I
authors.lastname: Apostolova
authors.forename: F
authors.initials: F
authors.lastname: Hofheinz
authors.forename: R
authors.initials: R
authors.lastname: Buchert
authors.forename: I G
authors.initials: IG
authors.lastname: Steffen
authors.forename: R
authors.initials: R
authors.lastname: Michel
authors.forename: C
authors.initials: C
authors.lastname: Rosner
authors.forename: V
authors.initials: V
authors.lastname: Prasad
authors.forename: C
authors.initials: C
authors.lastname: Köhler
authors.forename: T
authors.initials: T
authors.lastname: Derlin
authors.forename: W
authors.initials: W
authors.lastname: Brenner
authors.forename: S
authors.initials: S
authors.lastname: Marnitz
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D002584:Cervix Uteri / Q000098:blood supply / Q000473:pathology; D059248:Chemoradiotherapy; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008207:Lymphatic Metastasis / Q000473:pathology; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010104:Oxygen Radioisotopes; D055420:Perfusion Imaging / Q000379:methods*; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D002583:Uterine Cervical Neoplasms / Q000098:blood supply* / Q000473:pathology / Q000628:therapy
chemical_list: D001786:Blood Glucose; D010104:Oxygen Radioisotopes; D019788:Fluorodeoxyglucose F18