Evaluation of 3-Tesla MR Spectroscopy for assessment of bone marrow fat in patients with chronic kidney disease

Objectives: To evaluate bone marrow composition in patients with chronic kidney disease (CKD) by using MR Spectroscopy (MRS) and to determine whether bone marrow fat correlates with bone density and CKD severity. Methods: Thirty CKD patients underwent MRS and quantitative computed tomography (QCT), and 8 healthy controls underwent MRS at lumbar spine. Bone marrow fat content (FC) and volumetric bone mineral density (vBMD) of L1-L3 were determined from MRS and QCT respectively. CKD patients were divided into 3 groups according to glomerular filtration rate (GFR); for each patient, blood levels of parathyroid hormone (PTH) were also reported. Paired t tests, Pearson’s correlation coefficients and analysis of variance were applied. Results: The mean age of patients was 59.6 ± 11.5 years, mean GFR value was 21.5 ±8.8 ml/min and mean PTH value was 149.2 ± 53.1 pg/ml. FC at L1-L3 levels was significantly higher in CKD patients compared to controls (71.4 ± 8.7 vs 55.5± 7.6; p<0.001) and showed an inverse correlation with vBMD (r = -0.71; p<0.001). FC significantly increased from CKD group 1 to CKD group 3, with the decline of GFR (p = 0.002). There was no significant correlation between FC and PTH values (p>0.05). Conclusions: In CKD patients, bone marrow FC assessed by MRS at lumbar spine is higher than in healthy population, correlates with bone loss assessed by QCT and significantly increases with the worsening of renal function. MRS is a reliable and reproducible technique for quantification of bone marrow fat in CKD patients.