Use of dual-energy computed tomography to measure skeletal-wide marrow composition and cancellous bone mineral density.

Abstract

Temporal and spatial variations in bone marrow adipose tissue (MAT) can be indicative of several pathologies and confound current methods of assessing immediate changes in bone mineral remodeling. We present a novel dual-energy computed tomography (DECT) method to monitor MAT and marrow-corrected volumetric BMD (mcvBMD) throughout the body. Twenty-three cancellous skeletal sites in 20 adult female cadavers aged 40-80years old were measured using DECT (80 and 140kVp). vBMD was simultaneous recorded using QCT. MAT was further sampled using MRI. Thirteen lumbar vertebrae were then excised from the MRI-imaged donors and examined by microCT. After MAT correction throughout the skeleton, significant differences (p<0.05) were found between QCT-derived vBMD and DECT-derived mcvBMD results. McvBMD was highly heterogeneous with a maximum at the posterior skull and minimum in the proximal humerus (574 and 0.7mg/cc, respectively). BV/TV and BMC have a nearly significant correlation with mcvBMD (r=0.545, p=0.057 and r=0.539, p=0.061, respectively). MAT assessed by DECT showed a significant correlation with MRI MAT results (r=0.881, p<0.0001). Both DECT- and MRI-derived MAT had a significant influence on uncorrected vBMD (r=-0.86 and r=-0.818, p≤0.0001, respectively). Conversely, mcvBMD had no correlation with DECT- or MRI-derived MAT (r=0.261 and r=0.067). DECT can be used to assess MAT while simultaneously collecting mcvBMD values at each skeletal site. MAT is heterogeneous throughout the skeleton, highly variable, and should be accounted for in longitudinal mcvBMD studies. McvBMD accurately reflects the calcified tissue in cancellous bone.