title: Clinical value of combined positron emission tomography/computed tomography imaging in the interpretation of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography studies in cancer patients.
abstract: BACKGROUND
  Positron emission tomography (PET)/computed tomography (CT) is a new imaging modality that provides exact coregistration of anatomic and metabolic data. We have investigated to what degree this new technique might affect the interpretation of PET images in a nonselected group of consecutive cancer patients, reflecting routine condition in a busy cancer center.
  
  
  METHODS
  Whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-PET and PET/CT fusion image sets were compared in 100 consecutive, nonselected patients: 21 with head and neck cancer, 39 with chest malignancies, and 40 with malignancies of the abdomen and pelvis. All studies were performed for primary staging or evaluation of therapy and were interpreted by two nuclear medicine physicians also trained in radiology. Areas of abnormal FDG uptake were identified on PET and graded as likely benign, equivocal, or likely malignant. Positron emission tomography/computed tomography fusion images were then made available, and the initial findings were amended if necessary.
  
  
  RESULTS
  One hundred sixty-six areas with abnormal FDG uptake were identified. Based on PET alone, 51 sites were considered equivocal for malignancy. With PET/CT, the number of equivocal lesions decreased to 24. This difference is more marked in the head and neck as well as the abdomen and pelvis. When the equivocal sites were included in the analysis and grouped with the malignant sites, positive predictive value (PPV) of PET/CT was 89% compared with 75% for PET (p = 0.04).
  
  
  CONCLUSIONS
  Combined PET/CT results in increased reader confidence and 53% fewer equivocal readings, as well as improved PPV compared with PET alone.
authors.affiliation: Nuclear Medicine Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. yeungh@mskcc.org
authors.forename: Henry W D
authors.initials: HW
authors.lastname: Yeung
authors.forename: Heiko
authors.initials: H
authors.lastname: Schöder
authors.forename: Alex
authors.initials: A
authors.lastname: Smith
authors.forename: Mithat
authors.initials: M
authors.lastname: Gonen
authors.forename: Steven M
authors.initials: SM
authors.lastname: Larson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18