Investigation of MR decay rates in microphantom models of trabecular bone.
MR measurements of transverse relaxation time, T2*, in trabecular bone may provide both structural and density-related information for assessment of bone mineral status in osteoporosis. Using submillimeter scale glass phantoms as simplified models of trabecular bone, we have made a quantitative investigation of the dependence of T2* decay on modeled trabecular microstructure and MR image resolution. The experimental MR data are in excellent agreement with predictions from a computer simulation. Decreasing the modeled trabecular bone volume fraction, sigma, decreases the decay rate, as expected. However, if trabecular width and spacing are both increased without changing sigma, the decay rate is unchanged. The measured decay curves closely follow the predicted dependence on trabecular orientation. The decay rates are independent of image resolution, provided that the pixel dimensions are larger than the intertrabecular spacing. For smaller pixel sizes, the decay rate decreases with decreasing pixel size.
Selby
K
K
Magnetic Resonance Science Center, University of California at San Francisco 94143-0628, USA.
Majumdar
S
S
Newitt
D C
DC
Genant
H K
HK
D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000473:pathology; D003198:Computer Simulation; D003199:Computer Systems; D003287:Contrast Media; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D010024:Osteoporosis / Q000175:diagnosis*; D019047:Phantoms, Imaging
D003287:Contrast Media