Short- and long-term reproducibility of marrow adipose tissue quantification by 1H-MR spectroscopy.

Abstract

To assess short- and long-term reproducibility of marrow adipose tissue (MAT) quantification by 1H-MR spectroscopy. Our study was IRB-approved and HIPAA compliant. Written informed consent was obtained. We studied 20 overweight/obese but otherwise healthy subjects (12female, 8male) with a mean age of 37 ± 6years. 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 6weeks and 6months 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. 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). 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.