title: High resolution magnetic resonance imaging of the calcaneus: age-related changes in trabecular structure and comparison with dual X-ray absorptiometry measurements.
abstract: A high-resolution magnetic resonance imaging (MRI) protocol, together with specialized image processing techniques, was applied to the quantitative measurement of age-related changes in calcaneal trabecular structure. The reproducibility of the technique was assessed and the annual rates of change for several trabecular structure parameters were measured. The MR-derived trabecular parameters were compared with calcaneal bone mineral density (BMD), measured by dual X-ray absorptiometry (DXA) in the same subjects. Sagittal MR images were acquired at 1.5 T in 23 healthy women (mean age: 49.3 +/- 16.6 [SD]), using a three-dimensional gradient echo sequence. Image analysis procedures included internal gray-scale calibration, bone and marrow segmentation, and run-length methods. Three trabecular structure parameters, apparent bone volume (ABV/TV), intercept thickness (I.Th), and intercept separation (I.Sp) were calculated from the MR images. The short- and long-term precision errors (mean %CV) of these measured parameters were in the ranges 1-2% and 3-6%, respectively. Linear regression of the trabecular structure parameters vs. age showed significant correlation: ABV/TV (r2 = 33.7%, P < 0.0037), I.Th (r2 = 26.6%, P < 0.0118), I.Sp (r2 = 28.9%, P < 0.0081). These trends with age were also expressed as annual rates of change: ABV/TV (-0.52%/year), I.Th (-0.33%/year), and I.Sp (0.59%/year). Linear regression analysis also showed significant correlation between the MR-derived trabecular structure parameters and calcaneal BMD values. Although a larger group of subjects is needed to better define the age-related changes in trabecular structure parameters and their relation to BMD, these preliminary results demonstrate that high-resolution MRI may potentially be useful for the quantitative assessment of trabecular structure.
authors.affiliation: Department of Radiology, University of California, San Francisco 94143, USA.
authors.forename: X
authors.initials: X
authors.lastname: Ouyang
authors.forename: K
authors.initials: K
authors.lastname: Selby
authors.forename: P
authors.initials: P
authors.lastname: Lang
authors.forename: K
authors.initials: K
authors.lastname: Engelke
authors.forename: C
authors.initials: C
authors.lastname: Klifa
authors.forename: B
authors.initials: B
authors.lastname: Fan
authors.forename: F
authors.initials: F
authors.lastname: Zucconi
authors.forename: G
authors.initials: G
authors.lastname: Hottya
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.forename: S
authors.initials: S
authors.lastname: Majumdar
authors.forename: H K
authors.initials: HK
authors.lastname: Genant
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000367:Age Factors; D000368:Aged; D002111:Calcaneus / Q000000981:diagnostic imaging*; D002138:Calibration; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged