title: Short- and long-term reproducibility of marrow adipose tissue quantification by 1H-MR spectroscopy.
abstract: OBJECTIVE
  To assess short- and long-term reproducibility of marrow adipose tissue (MAT) quantification by 1H-MR spectroscopy.
  
  
  METHODS
  Our study was IRB-approved and HIPAA compliant. Written informed consent was obtained. We studied 20 overweight/obese but otherwise healthy subjects (12 female, 8 male) with a mean age of 37 ± 6 years. All subjects underwent proton magnetic resonance spectroscopy (1H-MRS) of the fourth lumbar vertebral body using a single-voxel point-resolved spatially localized spectroscopy sequence without water suppression at 3 T. Measurements were repeated after 6 weeks and 6 months using identical scanning protocols. The following clinical parameters were collected, weight, BMI, exercise status, and trabecular bone mineral density (BMD), by quantitative computed tomography. Short- (baseline, 6 weeks) and long-term (baseline, 6 months) reproducibility of MAT was assessed by the coefficient of variance (CV), standard deviation (SD), and interclass correlation coefficients (ICCs). Short- and long-term changes in clinical parameters were assessed by paired t-test.
  
  
  RESULTS
  For short-term reproducibility between baseline and 6-week scans, the CV was 9.9 %, SD was 0.08, and ICC was 0.97 (95 % CI 0.94-099). For long-term reproducibility between baseline and 6-month scans, the CV was 12.0 %, SD was 0.10, and ICC was 0.95 (95 % CI 0.88 to 0.98). There was no significant short- or long-term change in clinical parameters (weight, BMI, exercise status, BMD) (p > 0.2).
  
  
  CONCLUSIONS
  1H-MRS is a reproducible method for short- and long-term quantification of MAT. Our results can guide sample size calculations for interventional and longitudinal studies.
authors.affiliation: Pediatric Endocrine Unit, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MA, USA.|Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: Vibha
authors.initials: V
authors.lastname: Singhal
authors.affiliation: Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: Karen K
authors.initials: KK
authors.lastname: Miller
authors.affiliation: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Torriani
authors.affiliation: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. mbredella@mgh.harvard.edu.
authors.forename: Miriam A
authors.initials: MA
authors.lastname: Bredella
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D015519:Bone Density; D001853:Bone Marrow / Q000473:pathology; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology; D008297:Male; D009765:Obesity / Q000473:pathology*; D066244:Proton Magnetic Resonance Spectroscopy; D015203:Reproducibility of Results
keywords: Marrow adipose tissue; Proton MR spectroscopy; Reproducibility