title: Whole-Body MRI versus PET in assessment of multiple myeloma disease activity.
abstract: OBJECTIVE
  The purpose of this study was to compare FDG PET; whole-body MRI; and the reference standard, bone marrow aspiration and biopsy, to determine the best imaging technique for assessment of disease activity in multiple myeloma.
  
  
  METHODS
  Twenty-four patients (13 women, 11 men; mean age, 67.1 years; range, 44-83 years) with bone marrow biopsy-proven multiple myeloma were included in the study. All patients underwent PET/CT and whole-body MRI within 10 days of each other. Eight patients underwent more than one follow-up PET/CT and whole-body MRI examination, for a total of 34 pairs of images. Activity was defined as lesions with a maximum standardized uptake value greater than 2.5 at PET and as evidence of marrow packing at whole-body MRI. PET and whole-body MRI results were correlated with findings at bone marrow aspiration biopsy.
  
  
  RESULTS
  PET had a sensitivity of 59%, specificity of 75%, positive predictive value of 81%, and negative predictive value of 50% (p = 0.08). Whole-body MRI had a sensitivity of 68%, specificity of 83%, positive predictive value of 88%, and negative predictive value of 59% (p = 0.01). In 62% of cases, PET and whole-body MRI findings were concordant. When PET and whole-body MRI findings were concordant and positive, no false-positive results were found, yielding a specificity and a positive predictive value of 100% (p = 0.04).
  
  
  CONCLUSIONS
  Whole-body MRI performed better than PET in the assessment of disease activity, having a higher sensitivity and specificity. The positive predictive value of whole-body MRI in the assessment of active disease was high at 88%. When used in combination and with concordant findings, PET and whole-body MRI were found to have a specificity and positive predictive value of 100%, which may be of value to clinicians assessing the effectiveness of aggressive and expensive treatment regimens.
authors.affiliation: Department of Radiology and Diagnostic Imaging, Mater Misericordiae University Hospital, Dublin, Ireland.
authors.forename: Conor P
authors.initials: CP
authors.lastname: Shortt
authors.forename: Tadhg G
authors.initials: TG
authors.lastname: Gleeson
authors.forename: Karen A
authors.initials: KA
authors.lastname: Breen
authors.forename: John
authors.initials: J
authors.lastname: McHugh
authors.forename: Martin J
authors.initials: MJ
authors.lastname: O'Connell
authors.forename: Peter J
authors.initials: PJ
authors.lastname: O'Gorman
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Eustace
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D051598:Whole Body Imaging
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18