title: Improved imaging of intrahepatic colorectal metastases with 18F-fluorodeoxyglucose respiratory-gated positron emission tomography.
abstract: BACKGROUND
  In 18F-fluorodeoxyglucose PET/CT, respiratory motion induces bias in image interpretations (i.e. organ misregistration or lesion omission/underestimation).
  
  
  OBJECTIVE
  The present study applied our custom gating method (referred to as 'CT-based gated PET' and that has already been validated by our research group) to PET imaging of the liver and compared its per lesion sensitivity with that of standard clinical (i.e. ungated) PET.
  
  
  METHODS
  A total of 13 patients scheduled for liver surgery were referred to our department for PET/CT imaging. Each patient underwent both ungated and CT-based gated PET imaging protocols. Two independent, blinded observers interpreted the two sets of PET images and reached a consensus when necessary. Image interpretations were combined with histological analysis and/or intraoperative ultrasound examination to compute each method's per lesion sensitivity and true positive fraction. Analyses were also performed by considering lesions according to their size (longest axis over 10 mm or over 15 mm).
  
  
  RESULTS
  Forty-eight lesions were confirmed by pathology reports. When considering all the uptakes, the ungated and the CT-based gated PET methods had sensitivities of 54.2 and 64.6% (P=0.025) and true positive fractions of 83.9 and 86.1%, respectively. When considering uptakes greater than 10 mm in size, ungated and CT-based gated PET had sensitivities of 74.3 and 88.6% (P=0.025), respectively. For lesions greater than 15 mm in size, the corresponding sensitivities were 85.2 and 100% (P=0.046).
  
  
  CONCLUSIONS
  CT-based gated PET yielded a higher lesion-based sensitivity than routine, ungated PET did. Hence, this method improves the detection of intrahepatic colorectal metastases--especially for lesions that are close in size to the detection limit of the PET gantry.
authors.affiliation: Department of Clinical Trial and Innovation, Amiens University Medical Centre, Amiens, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Fin
authors.forename: Joël
authors.initials: J
authors.lastname: Daouk
authors.forename: Pascal
authors.initials: P
authors.lastname: Bailly
authors.forename: Jérôme
authors.initials: J
authors.lastname: Slama
authors.forename: Julie
authors.initials: J
authors.lastname: Morvan
authors.forename: Isabelle
authors.initials: I
authors.lastname: El Esper
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Régimbeau
authors.forename: Denis
authors.initials: D
authors.lastname: Chatelain
authors.forename: Momar
authors.initials: M
authors.lastname: Diouf
authors.forename: Marc-Etienne
authors.initials: ME
authors.lastname: Meyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18