18F-fluoride Positron Emission Tomography Measurements of Regional Bone Formation in Hemodialysis Patients with Suspected Adynamic Bone Disease

18F-fluoride positron emission tomography (18F-PET) allows the assessment of regional bone formation and could have a role in the diagnosis of adynamic bone disease (ABD) in patients with chronic kidney disease (CKD). The purpose of this study was to examine bone formation at multiple sites of the skeleton in hemodialysis patients (CKD5D) and assess the correlation with bone biopsy. Seven CKD5D patients with suspected ABD and 12 osteoporotic postmenopausal women underwent an 18F-PET scan, and bone plasma clearance, Ki, was measured at ten skeletal regions of interest (ROI). Fifteen subjects had a transiliac bone biopsy following double tetracycline labeling. Two CKD5D patients had ABD confirmed by biopsy. There was significant heterogeneity in Ki between skeletal sites, ranging from 0.008 at the forearm to 0.028 mL/min/mL at the spine in the CKD5D group. There were no significant differences in Ki between the two study groups or between the two subjects with ABD and the other CKD5D subjects at any skeletal ROI. Five biopsies from the CKD5D patients had single tetracycline labels only, including the two with ABD. Using an imputed value of 0.3 μm/day for mineral apposition rate (MAR) for biopsies with single labels, no significant correlations were observed between lumbar spine Ki corrected for BMAD (Ki/BMAD) and bone formation rate (BFR/BS), or MAR. When biopsies with single labels were excluded, a significant correlation was observed between Ki/BMAD and MAR (r = 0.81, p = 0.008) but not BFR/BS. Further studies are required to establish the sensitivity of 18F-PET as a diagnostic tool for identifying CKD patients with ABD.