title: PET/CT in lymphoma: prospective study of enhanced full-dose PET/CT versus unenhanced low-dose PET/CT.
abstract: PET/CT combines functional and morphologic data and increases diagnostic accuracy in a variety of malignancies. This study prospectively compares the agreement between contrast-enhanced full-dose PET/CT and unenhanced low-dose PET/CT in lesion detection and initial staging of Hodgkin's disease and non-Hodgkin's lymphoma.
  
  
  METHODS
  Forty-seven biopsy-proven lymphoma patients underwent a 18F-FDG PET/CT study that included unenhanced low-dose CT and enhanced full-dose CT for initial staging. Patients who had undergone previous diagnostic CT for initial staging were excluded. For every patient, each modality of PET/CT images was evaluated by either of 2 pairs of readers, with each pair comprising 1 experienced radiologist and 1 experienced nuclear physician. While evaluating one of the 2 types of PET/CT, the readers were unaware of the results of the other type. Lesion detection, number of sites affected in each anatomic region, and disease stage were assessed. Agreement between techniques was determined by the kappa-statistic, and discordances were studied by the McNemar test. Clinical, analytic, histopathologic, diagnostic CT, and PET data; data from other imaging techniques; and follow-up data constituted the reference standard.
  
  
  RESULTS
  For region-based analysis, no significant differences were found between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT, although full-dose PET/CT showed fewer indeterminate findings and a higher number of extranodal sites affected than did low-dose PET/CT. Agreement between the 2 types of PET/CT was almost perfect for disease stage (kappa = 0.92; P < 0.001).
  
  
  CONCLUSIONS
  Our study showed a good correlation between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT for lymph node and extranodal disease in lymphomas, suggesting that unenhanced low-dose PET/CT might suffice in most patients as the only imaging technique for the initial staging of lymphomas, reserving diagnostic CT for selected cases.
authors.affiliation: Department of Radiology, University Hospital La Paz, Madrid, Spain. beatrizrodriguezvigil@yahoo.es
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rodríguez-Vigil
authors.forename: Nieves
authors.initials: N
authors.lastname: Gómez-León
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Pinilla
authors.forename: Dolores
authors.initials: D
authors.lastname: Hernández-Maraver
authors.forename: Juan
authors.initials: J
authors.lastname: Coya
authors.forename: Luis
authors.initials: L
authors.lastname: Martín-Curto
authors.forename: Rosario
authors.initials: R
authors.lastname: Madero
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D006689:Hodgkin Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D011829:Radiation Dosage; D011860:Radiography, Abdominal; D012598:Sclerosis; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019788:Fluorodeoxyglucose F18