title: Marrow Adipose Tissue Quantification of the Lumbar Spine by Using Dual-Energy CT and Single-Voxel (1)H MR Spectroscopy: A Feasibility Study.
abstract: OBJECTIVE
  To test the performance of dual-energy computed tomography (CT) in the assessment of marrow adipose tissue (MAT) content of the lumbar spine by using proton (hydrogen 1 [(1)H]) magnetic resonance (MR) spectroscopy as a reference standard and to determine the influence of MAT on the assessment of bone mineral density (BMD).
  
  
  METHODS
  This study was institutional review board approved and complied with HIPAA guidelines. Written informed consent was obtained. Twelve obese osteopenic but otherwise healthy subjects (mean age ± standard deviation, 43 years ± 13) underwent 3-T (1)H MR spectroscopy of the L2 vertebra by using a point-resolved spatially localized spectroscopy sequence without water suppression. The L2 vertebra was scanned with dual-energy CT (80 and 140 kV) by using a dual-source multi-detector row CT scanner with a calibration phantom. Mean basis material composition relative to the phantom was estimated in the L2 vertebra. Volumetric BMD was measured with and without correction for MAT. Bland-Altman 95% limits of agreement and Pearson correlation coefficients were calculated.
  
  
  RESULTS
  There was excellent agreement between (1)H MR spectroscopy and dual-energy CT, with a mean difference in fat fraction of -0.02 between the techniques, with a 95% confidence interval of -0.24, 0.20. There was a strong correlation between marrow fat fraction obtained with (1)H MR spectroscopy and that obtained with dual-energy CT (r = 0.91, P < .001). The presence of MAT led to underestimation of BMD, and this bias increased with increasing MAT content (P < .001).
  
  
  CONCLUSIONS
  Dual-energy CT can be used to assess MAT content and BMD of the lumbar spine in a single examination and provides data that closely agree and correlate with (1)H MR spectroscopy data.
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: Miriam A
authors.initials: MA
authors.lastname: Bredella
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: Scott M
authors.initials: SM
authors.lastname: Daley
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: Mannudeep K
authors.initials: MK
authors.lastname: Kalra
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: J Keenan
authors.initials: JK
authors.lastname: Brown
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: Karen K
authors.initials: KK
authors.lastname: Miller
authors.affiliation: From the Department of Radiology (M.A.B., S.M.D., M.K.K., M.T.) and Neuroendocrine Unit (K.K.M.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Mindways Software, Austin, Tex (J.K.B.).
authors.forename: Martin
authors.initials: M
authors.lastname: Torriani
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015519:Bone Density; D001853:Bone Marrow / Q000033:anatomy & histology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011522:Protons; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D011522:Protons