Magnetic resonance bone densitometry. Comparison of different methods based on susceptibility.
OBJECTIVE
Three different magnetic resonance techniques for the assessment of the density of trabecular bone are presented and compared.


METHODS
All methods are based on the susceptibility difference between marrow and bony components. Localized spectroscopic (PRESS single voxel spectroscopy) and two different imaging approaches (FLASH gradient echo imaging and MAGSUS imaging) are demonstrated to be sensitive to the trabecular structures on application to the distal femur of a healthy volunteer. This region was chosen because a continuous rarefication of the trabecular density from the epiphysis to the metaphysis occurs physiologically. In addition, results from the heel-bones of five young healthy volunteers were compared with data from three patients with severe osteoporosis.


RESULTS
All methods allowed differentiation between the two groups. Advantages and disadvantages of the methods concerning spatial resolution, preparation and measuring time, necessity of postprocessing, problems with shim adjustment, and occurrence of several chemical shift components are reported. The MAGSUS technique combines simple application and avoidance of postprocessing for at least qualitative assessment of bone density with sufficient spatial resolution.


CONCLUSIONS
A reliable assessment of osteoporosis by magnetic resonance is possible in peripheral marrow regions of adults. Further studies are needed to establish standard measuring protocols.
Schick
F
F
Department of Diagnostic Radiology, University of Tübingen, Federal Republic of Germany.
Seitz
D
D
Machann
J
J
Lutz
O
O
Claussen
C D
CD
D000328:Adult; D000368:Aged; D015519:Bone Density; D002111:Calcaneus / Q000033:anatomy & histology / Q000473:pathology; D005260:Female; D005269:Femur / Q000033:anatomy & histology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D015663:Osteoporosis, Postmenopausal / Q000175:diagnosis*