Susceptibility effects of bone trabeculae. Quantification in vivo using an asymmetric spin-echo technique.
OBJECTIVE
The authors assessed the capability of magnetic resonance imaging in measuring bone mineral density in vivo.


METHODS
Using the in-phase asymmetric spin-echo technique, the susceptibility effect (T2*susceptibility) was measured in lumbar vertebrae in vivo. Calcium density was measured with single energy quantitative computed tomography scan. The values of the susceptibility effect were correlated with calcium density.


RESULTS
A statistically significant positive correlation was observed between signal loss due to susceptibility-induced inhomogeneity and the calcium density in the region of interest. The change in 1/T2*susceptibility per unit change in density was 0.114 seconds-1/mg/cm3. T2*susceptibility was 14.3 mseconds in volunteers and 17.4 mseconds in postoophorectomy patients.


CONCLUSIONS
To some extent, quantification of bone density is possible using magnetic resonance imaging; however, the relatively wide dispersion of the susceptibility effect, plotted against the calcium density in the axial skeleton, indicates that other factors, such as the three-dimensional structure of bone trabeculae, may play important roles in determining magnetic resonance parameters.
Sugimoto
H
H
Department of Radiology, Jichi Medical School, Japan.
Kimura
T
T
Ohsawa
T
T
D000328:Adult; D000368:Aged; D015519:Bone Density; D001842:Bone and Bones / Q000473:pathology*; D002113:Calcification, Physiologic; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D010024:Osteoporosis / Q000175:diagnosis