Proximal femur: assessment for osteoporosis with T2* decay characteristics at MR imaging

Abstract

Purpose: To use T2* measurements at magnetic resonance (MR) imaging to investigate the trabecular structure of the hip in women with and women without osteoporotic hip fractures and to compare this technique with bone mineral density (BMD) measurements in the diagnosis of fractures.

Materials and methods: T2* maps of the proximal femur were obtained at 1.5 T in 23 postmenopausal study patients with osteoporotic hip fractures, 27 age-matched healthy postmenopausal control subjects, and five healthy premenopausal control subjects. A modified gradient-recalled acquisition in the steady state, or GRASS, sequence was used with echo times of 4-40 msec at 4-msec increments. T2* values were measured in five regions of interest: femoral neck, the Ward triangle, trochanter, intertrochanteric region, and total proximal femur. Additionally, BMD measurements of the hip were obtained with dual x-ray absorptiometry.

Results: Significant differences between T2* measurements were obtained in all three groups (P < .05). BMD measurements of the hip also showed significant differences (P < .05). For T2* and BMD measurements, odds ratios and areas under the curve in receiver operating characteristic analysis were comparable. Correlations between 1/T2* values and BMD were significant (P < .05). T2* measurements in the proximal femur showed regional variations.

Conclusion: MR imaging decay characteristics of bone marrow could be used to differentiate between postmenopausal women with and those without osteoporotic hip fractures.