title: Whole-body diffusion-weighted imaging: the added value to whole-body MRI at initial diagnosis of lymphoma.
abstract: OBJECTIVE
  The objective of our study was to evaluate the diagnostic performance of conventional whole-body MRI without and with diffusion-weighted imaging (DWI) in the detection of known (18)F-FDG-avid lymphomas. The conventional whole-body MRI protocol consisted of a T2-weighted sequence and a T2-weighted spectral attenuated inversion recovery (SPAIR) sequence with frequency-selective fat suppression. The second protocol used the same sequences as the first protocol but also included DWI.
  
  
  METHODS
  Seventeen patients with pathologically confirmed, newly diagnosed, untreated lymphoma were recruited. T2-weighted and T2-weighted SPAIR images were evaluated first, separate from the DW images, and then were evaluated with the DW images. We used (18)F-FDG PET/CT as the standard of reference. True-positive, false-positive, and false-negative values were evaluated on a per-lesion basis. Tumor staging based on T2-weighted and T2-weighted SPAIR imaging without DWI and then with DWI was compared using the Ann Arbor staging system.
  
  
  RESULTS
  True-positive lesions were increased from 89% to 97%, false-positive lesions were increased from 3% to 6%, and false-negative lesions were decreased from 11% to 3% by the addition of DWI. Diagnostic sensitivity was significantly increased (p = 0.002) by adding DWI. Lesions detected on DWI but not on T2-weighted and T2-weighted SPAIR imaging were located in renal (n = 1), paraaortic (n = 6), and pelvic (n = 3) lymph nodes. On DWI, 47% of the lesions (n = 55) were more conspicuous than on T2-weighted and T2-weighted SPAIR imaging; most of these lesions (58%, n = 32) were from lymph nodes in the pelvic or abdominal regions and bone marrow. No difference was found between T2-weighted and T2-weighted SPAIR imaging without DWI and T2-weighted and T2-weighted SPAIR imaging with DWI in lymphoma staging, being consistent with PET/CT in 88% of the patients (n = 15).
  
  
  CONCLUSIONS
  The addition of DWI to conventional whole-body MRI sequences enhanced lesion conspicuity and improved diagnostic accuracy for lymphomas. With technical optimization, whole-body MRI with DWI, as a nonionizing imaging modality, may potentially be useful as an alternative method to PET/CT in the management of malignant lymphoma.
authors.affiliation: Department of Diagnostic Radiology, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Rd, Rm 406, Block K, Hong Kong.
authors.forename: Jing
authors.initials: J
authors.lastname: Gu
authors.forename: Tao
authors.initials: T
authors.lastname: Chan
authors.forename: Jingbo
authors.initials: J
authors.lastname: Zhang
authors.forename: Anskar Y H
authors.initials: AY
authors.lastname: Leung
authors.forename: Yok-Lam
authors.initials: YL
authors.lastname: Kwong
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008223:Lymphoma / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18