CANCELLOUS BONE VOLUME AND STRUCTURE IN THE FOREARM - NONINVASIVE ASSESSMENT WITH MR MICROIMAGING AND IMAGE-PROCESSING

PURPOSE: To develop and apply a method for the derivation of cancellou s bone architectural parameters from in vivo magnetic resonance (MR) i mages of the distal radius and to evaluate these parameters as predict ors of vertebral fracture status in osteopenia. MATERIALS AND METHODS: MR images (137 x 137 x 500-mu m(3) voxel size) were acquired with a t hree-dimensional partial flip-angle spin-echo pulse sequence in the di stal radius of 36 women. Subjects were classified as healthy or with o steoporosis on the basis of vertebral deformity and bone mineral densi ty (BMD). Images rated as of adequate quality in 20 subjects were proc essed with a method that is applicable in the limited spatial resoluti on regime. The method relies on histogram deconvolution to Obviate bin ary segmentation. Cancellous bone structure was treated as a quasi-reg ular lattice and analyzed with spatial autocorrelation, yielding param eters that quantify intertrabecular spacing, contiguity, and a measure of longitudinal alignment called tubularity. RESULTS: Whereas neither BMD nor any of the structural parameters individually correlated sign ificantly with vertebral deformity fraction, a simple function that in volved tubularity and longitudinal spacing predicted deformity fractio n well (r = .78, P < .005). CONCLUSION: Histomorphometric parameters c haracterizing cancellous bone in the distal radius can be derived from in vivo MR microimages and are predictive of vertebral deformity.