title: Bone marrow uptake of indolent non-Hodgkin lymphoma on PET/CT with histopathological correlation.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of PET/computed tomography (CT) in detecting marrow infiltration in indolent non-Hodgkin lymphoma (NHL) with histopathological correlation.
  
  
  METHODS
  All treatment-naive newly diagnosed indolent NHL with staging PET/CT were retrospectively evaluated for marrow infiltration and categorized on the basis of the PET/CT uptake pattern: normal (PET/CT negative), focal/diffuse (PET/CT positive). Bone marrow biopsy (BMB) was considered the standard, except in focal PET/CT uptake, which was confirmed to be positive or negative by serial PET/CT. The BMB pattern was assessed as diffuse and nondiffuse and the degree of lymphoid infiltration was documented.
  
  
  RESULTS
  Forty-six patients (mean age 59 ± 15 years) were evaluated. In the PET/CT-positive group of 22 cases (diffuse = 15, focal = 7), BMB was positive in 21 cases. In 80% of diffuse PET/CT uptake cases, a diffuse BMB infiltrative pattern was observed. However, in cases with focal PET/CT uptake, no predominant histological pattern was observed. No correlation was found between semiquantitative uptake and degree of lymphoid infiltration on BMB (r = 0.2, P = 0.434). In the PET/CT-negative group of 24 cases, 20 cases were BMB negative and four cases were positive. The overall diagnostic accuracy of PET/CT in determining marrow infiltration was 89% (sensitivity 84%, specificity 95%, positive predictive value 95% and negative predictive value 83%).
  
  
  CONCLUSIONS
  PET/CT showed high specificity and positive predictive value with moderate accuracy in detecting marrow disease in indolent NHL. The metabolic uptake lacked a significant correlation with the degree of lymphoid infiltration, but a potential relationship may exist between the pattern of metabolic uptake and the BMB infiltrative pattern.
authors.affiliation: aDepartment of Diagnostic Radiology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine bDepartment of Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong cDepartment of Radiology, Zhongshan Hospital, Xiamen University, Fujian, China.
authors.forename: Elaine Yuen Phin
authors.initials: EY
authors.lastname: Lee
authors.forename: Harinder
authors.initials: H
authors.lastname: Gill
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yok-Lam
authors.initials: YL
authors.lastname: Kwong
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
mesh_terms: D001692:Biological Transport; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed