title: Does Delayed-Time-Point Imaging Improve 18F-FDG-PET in Patients With MALT Lymphoma?: Observations in a Series of 13 Patients.
abstract: OBJECTIVE
  To determine whether in patients with extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue lymphoma (MALT), delayed-time-point 2-F-fluoro-2-deoxy-d-glucose-positron emission tomography (F-FDG-PET) performs better than standard-time-point F-FDG-PET.
  
  
  METHODS
  Patients with untreated histologically verified MALT lymphoma, who were undergoing pretherapeutic F-FDG-PET/computed tomography (CT) and consecutive F-FDG-PET/magnetic resonance imaging (MRI), using a single F-FDG injection, in the course of a larger-scale prospective trial, were included. Region-based sensitivity and specificity, and patient-based sensitivity of the respective F-FDG-PET scans at time points 1 (45-60 minutes after tracer injection, TP1) and 2 (100-150 minutes after tracer injection, TP2), relative to the reference standard, were calculated. Lesion-to-liver and lesion-to-blood SUVmax (maximum standardized uptake values) ratios were also assessed.
  
  
  RESULTS
  F-FDG-PET at TP1 was true positive in 15 o f 23 involved regions, and F-FDG-PET at TP2 was true-positive in 20 of 23 involved regions; no false-positive regions were noted. Accordingly, region-based sensitivities and specificities were 65.2% (confidence interval [CI], 45.73%-84.67%) and 100% (CI, 100%-100%) for F-FDG-PET at TP1; and 87.0% (CI, 73.26%-100%) and 100% (CI, 100%-100%) for F-FDG-PET at TP2, respectively. FDG-PET at TP1 detected lymphoma in at least one nodal or extranodal region in 7 of 13 patients, and F-FDG-PET at TP2 in 10 of 13 patients; accordingly, patient-based sensitivity was 53.8% (CI, 26.7%-80.9%) for F-FDG-PET at TP1, and 76.9% (CI, 54.0%-99.8%) for F-FDG-PET at TP2. Lesion-to-liver and lesion-to-blood maximum standardized uptake value ratios were significantly lower at TP1 (ratios, 1.05 ± 0.40 and 1.52 ± 0.62) than at TP2 (ratios, 1.67 ± 0.74 and 2.56 ± 1.10; P = 0.003 and P = 0.001).
  
  
  CONCLUSIONS
  Delayed-time-point imaging may improve F-FDG-PET in MALT lymphoma.
authors.affiliation: From the *Department of Biomedical Imaging and Image-guided Therapy, †Centre for Medical Physics and Biomedical Engineering, ‡Department of Internal Medicine I, §Institute of Pathology, ||Department of Internal Medicine III, and ¶Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
authors.forename: Marius E
authors.initials: ME
authors.lastname: Mayerhoefer
authors.forename: Chiara
authors.initials: C
authors.lastname: Giraudo
authors.forename: Daniela
authors.initials: D
authors.lastname: Senn
authors.forename: Markus
authors.initials: M
authors.lastname: Hartenbach
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Ivo
authors.initials: I
authors.lastname: Rausch
authors.forename: Barbara
authors.initials: B
authors.lastname: Kiesewetter
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Herold
authors.forename: Marcus
authors.initials: M
authors.lastname: Hacker
authors.forename: Matthias
authors.initials: M
authors.lastname: Pones
authors.forename: Ingrid
authors.initials: I
authors.lastname: Simonitsch-Klupp
authors.forename: Leonhard
authors.initials: L
authors.lastname: Müllauer
authors.forename: Werner
authors.initials: W
authors.lastname: Dolak
authors.forename: Julius
authors.initials: J
authors.lastname: Lukas
authors.forename: Markus
authors.initials: M
authors.lastname: Raderer
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18