BONE DISEASE IN RENAL PATIENTS is a universal

Purpose: To explore the potential role of micro-magnetic resonance imaging (-MRI) for quantifying trabecular and cortical bone structural parameters in renal osteodystro-phy (ROD), a multifactorial disorder of bone metabolism, traditionally evaluated by bone biopsy. Materials and Methods: Seventeen hemodialysis patients (average PTH level 502 415 g/liter) were compared with 17 age-, gender-, and body mass index (BMI)-matched control subjects. The average dialysis duration for the pa-tients was 5.5 years (range 0.96-18.2 years). Three-di-mensional (3D) fast large-angle spin-echo (FLASE) MR im-ages of the distal tibia (voxel size 137 137 410 m3) were processed to yield bone volume fraction (BV/TV). From a skeletonized representation of the trabecular bone network, the topology of each bone voxel was determined providing surface and curve voxel densities (SURF and CURV) and the topological erosion index (EI). Further, high-resolution two-dimensional (2D) spin-echo images were collected at the tibial midshaft for measurement of cortical bone cross-sectional area (CCA), relative CCA expressed as a percentage of total bone area (RCA), and mean cortical thickness (MCT). Results: The data show both RCA andMCT to be lower in the patients (61.2 vs. 69.1%, P 0.008, and 4.53 vs. 5.19 mm, P 0.01). BV/TV and SURF were lower, while EI was in-creased in the patients, although these differences were not quite significant (P 0.06-0.09). All of the cortical and tra-becular findings are consistent with increased bone fragility. Conclusion: The data suggest that -MRImay have potential to characterize the structural implications of metabolic bone disease, potentially providing a noninvasive tool for the evaluation of therapies for ROD. Key Words: magnetic resonance imaging; renal osteodys-trophy; trabecular bone; cortical bone; bone architectur