title: Improvement of early 18F-FDG PET interpretation in diffuse large B-cell lymphoma: importance of the reference background.
abstract: This study investigated whether the reference background above which a residual mass is considered positive in the International Harmonization Project criteria should be modified for early (18)F-FDG PET evaluation.
  
  
  METHODS
  In 92 patients with newly diagnosed diffuse large B-cell lymphoma, the maximal standardized uptake value (SUVmax) was measured on post-cycle 2 PET in the most intense residual mass (or, in the case of negative PET findings, in the area of most intense tumor uptake before therapy), in the mediastinal blood pool (MBP) and the liver, as potential reference background tissues.
  
  
  RESULTS
  With MBP as a reference (SUVmax, 2.0 ± 0.6), PET was unable to distinguish early responders from nonresponders. In contrast, with liver as a reference (SUVmax, 2.5 ± 0.7), 2-y progression-free survival was significantly different between patients with PET-negative findings (81.8% [95% confidence interval, 71%-93%]) and patients with PET-positive findings (51.8% [95% confidence interval, 35%-69%], P = 0.003).
  
  
  CONCLUSIONS
  When assessing early response, particularly in risk-adapted therapeutic trials, it seems preferable to refer to a background tissue (liver) with a higher level of uptake than that of current international criteria (MBP) which were designed for end-of-treatment evaluation.
authors.affiliation: Department of Nuclear Medicine, H Mondor Hospital, Assistance Publique-Hôpitaux de Paris, Créteil, France. emmanuel.itti@hmn.aphp.fr
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Itti
authors.forename: Malik E
authors.initials: ME
authors.lastname: Juweid
authors.forename: Corinne
authors.initials: C
authors.lastname: Haioun
authors.forename: Imene
authors.initials: I
authors.lastname: Yeddes
authors.forename: Fatma
authors.initials: F
authors.lastname: Hamza-Maaloul
authors.forename: Intidhar
authors.initials: I
authors.lastname: El Bez
authors.forename: Eva
authors.initials: E
authors.lastname: Evangelista
authors.forename: Chieh
authors.initials: C
authors.lastname: Lin
authors.forename: Jehan
authors.initials: J
authors.lastname: Dupuis
authors.forename: Michel
authors.initials: M
authors.lastname: Meignan
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D018572:Disease-Free Survival; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D053208:Kaplan-Meier Estimate; D008099:Liver / Q000000981:diagnostic imaging; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging* / Q000188:drug therapy; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18