title: Multiphase CT scanning and different intravenous contrast media concentrations in combined F-18-FDG PET/CT: Effect on quantitative and clinical assessment.
abstract: OBJECTIVE
  To evaluate the influence of multiphase CT scanning and different intravenous contrast media on contrast enhancement, attenuation correction and image quality in combined PET/CT.
  
  
  METHODS
  140 patients were prospectively enrolled for F-18-FDG-PET/CT including a low-dose unenhanced, arterial and venous contrast enhanced CT. The first (second) 70 patients, received contrast medium with 370 (300) mg iodine/ml. The iodine delivery rate (1.3mg/s) and total iodine load (44.4g) were identical for both groups. Contrast enhancement and maximum and mean standardized FDG uptake values (SUVmax and SUVmean) were determined for the un-enhanced, arterial and venous PET/CT at multiple anatomic sites and PET reconstructions were visually evaluated.
  
  
  RESULTS
  Arterial contrast enhancement was significantly higher for the 300mg/ml contrast medium compared to 370mgI/ml at all anatomic sites. Venous enhancement was not different between the two contrast media. SUVmean and SUVmax were significantly higher for the contrast enhanced compared to the non-enhanced PET/CT at all anatomic sites (all P<0.001). Tracer uptake was significantly higher in the arterial than in the venous PET/CT in the arteries using both contrast media (all P<0.001). No differences in tracer uptake were found between the contrast media (all P>0.05). Visual assessment revealed no relevant differences between the different PET reconstructions.
  
  
  CONCLUSIONS
  There is no relevant qualitative influence on the PET scan from the use of different intravenous contrast media in its various phases in combined multiphase PET/CT. For quantitative analysis of tracer uptake it is required to use an identical PET/CT protocol.
authors.affiliation: Department of Nuclear Medicine, University Hospital RWTH Aachen, Pauwelsstraße 30, 52057 Aachen, Germany. Marilou.Rebiere@rwth-aachen.de
authors.forename: Marilou
authors.initials: M
authors.lastname: Rebière
authors.forename: Frederik A
authors.initials: FA
authors.lastname: Verburg
authors.forename: Moritz
authors.initials: M
authors.lastname: Palmowski
authors.forename: Thomas
authors.initials: T
authors.lastname: Krohn
authors.forename: Hubertus
authors.initials: H
authors.lastname: Pietsch
authors.forename: Christiane K
authors.initials: CK
authors.lastname: Kuhl
authors.forename: Felix M
authors.initials: FM
authors.lastname: Mottaghy
authors.forename: Florian F
authors.initials: FF
authors.lastname: Behrendt
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage; D006801:Humans; D007262:Infusions, Intravenous; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009369:Neoplasms / Q000175:diagnosis*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D007472:Iohexol; C038192:iopromide