Introduction

Osteoporosis is a systemic skeletal disease, it is characterized by low bone mass, poor structure, and increased risk of fracture1. Trabecular bone is highly responsive to metabolic stimuli and has a turnover rate ~8 times higher than that of cortical bone, making it a main index for detecting bone loss in early osteoporosis (OP)2. In this study, we utilized a broadband adiabatic inversion recovery prepared 3D UTE cones (3D IR‐UTE‐cones) sequence3 to investigate the characterizations of trabecular bone in human lumbar and to further evaluate the correlations between lumbar PD and BMD, age, gender, ODI, respectively, in osteoporosis patients.

Methods

10 osteoporosis patients (age 48±12 years, age range 40-76 years) were recruited. All patients underwent 3D IR‐UTE‐cones sequence of lumbar on a 3.0T MR station (Signa, Pioneer, GE Healthcare). A phantom with a T2*around 0.34 ms was placed between the patients and the spine coil during scanning to serve as a reference to calibrate the proton density of trabecular bone3. The UTE sequence parameters were as follows: TR/TI = 150/64 ms, TE = 0.032 ms, flip angle = 18°, FOV = 30cm × 30cm, matrix = 140 × 140, oversampling factor = 2, and scan time = 10 min. QCT examinations of the lumbar region in the supine position were performed on a 64-detector CT scanner (Aquilion 64, Toshiba, Tokyo, Japan) for each subject. The QCT images were acquired using the following parameters: tube voltage, 120 kVp; tube current, 150 mA; rotation time,500 msec; slice thickness, 1 mm; and field of view (FOV), 50cm × 50 cm. Regions of interest (ROIs) were placed in the vertebral body, avoiding cortical bone. Mean lumbar PD was computed for each subject by averaging the PD measurements from three vertebrae (L3–L5). Pearson correlation analysis was performed to calculate the correlations between lumbar PD and BMD, age, gender, ODI, respectively, in osteoporosis patients. A value of P < 0.05 was considered as a statistically significant.

Results

The lumbar UTE images of each participants were successfully acquired in our study (Figure 1). The lumbar PD showed a moderate positive correlation with BMD (r = 0.459, P < 0.05) (Figure 2). In addition, our results demonstrated that the lumbar PD is negatively correlated with age (r = -0.689, P < 0.05) and ODI (r = -0.676, P < 0.05), while had no association with gender. The results were summarized in table 1.

Discussion and Conclusion

To our best knowledge, this is a preliminary study of applying PD measured by IR-UTE MRI in lumbar. It is concluded that PD of the lumbar can be achieved by using a clinical 3.0T MRI with a 10 mins IR-UTE sequence. The decreased PD in the osteoporotic lumbar vertebrae could be partly explained by the decreased BMD. Accurate evaluation of trabecular bone is worthwhile, because most osteoporotic fractures occur at locations with rich trabecular bone4. It is feasible that PD can be applied in the diagnosis of osteoporosis using IR-UTE. Overall, it is supposed that the IR-UTE based imaging biomarkers could be utilized to predict compression fracture of lumbar.

Acknowledgements

No acknowledgement found.