title: Can whole-body low-dose multidetector CT exclude the presence of myeloma bone disease in patients with monoclonal gammopathy of undetermined significance (MGUS)?
abstract: OBJECTIVE
  To determine the benefit of using whole-body low-dose computed tomography (WBLD-CT) in patients with monoclonal gammopathy of undetermined significance (MGUS) for exclusion of multiple myeloma (MM) bone disease.
  
  
  METHODS
  Seventy-one consecutive patients with confirmed MGUS (as defined by the latest criteria of the International Myeloma Working Group) who underwent WBLD-CT for diagnosis were identified retrospectively by a search of our institution's electronic medical record database (2002-2009). Patients were classified as low-risk or intermediate/high-risk and followed over a ≥2-year period with additional CT imaging and/or laboratory parameters. Presence of osteolysis, medullary, or extramedullary abnormalities compatible with involvement by MM was recorded. A diffuse or focal increase in medullary density to Hounsfield unit (HU) values >20 HU/>0 HU was considered suspicious for bone marrow infiltration if no other causes identifiable.
  
  
  RESULTS
  The presence of osteolysis was excluded in all 71 patients with MGUS at initial diagnosis and patients were surveilled for ≥2 years. Lytic changes were observed at follow-up in 1/71 patients that progressed to MM and were detectable via WBLD-CT at an early stage (even before a significant rise in M-protein was recorded). In 3/71 patients with MGUS (4%) suspicious bone marrow attenuation values were measured, disclosing disease progression to smoldering myeloma in another patient and false-positive results in 2/71 patients. Bone marrow attenuation assessment resulted in a specificity and negative predictive value of 97%, respectively. No significant difference with respect to bone marrow attenuation was observed in patients with low-risk MGUS versus intermediate- to high-risk MGUS. One of 71 patients showed serologic disease progression to active MM without bone abnormalities detectable.
  
  
  CONCLUSIONS
  WBLD-CT reliably excludes findings compatible with myeloma in MGUS and thereby complements hematologic laboratory analysis.
authors.affiliation: Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. daniel.spira@med.uni-tuebingen.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Spira
authors.forename: Katja
authors.initials: K
authors.lastname: Weisel
authors.forename: Harald
authors.initials: H
authors.lastname: Brodoefel
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schulze
authors.forename: Sascha
authors.initials: S
authors.lastname: Kaufmann
authors.forename: Marius
authors.initials: M
authors.lastname: Horger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000000981:diagnostic imaging*; D009101:Multiple Myeloma / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods*