Detection and Monitoring of Osteoporosis in a Rat Model by Thermoacoustic Tomography

Objectives: Osteoporosis is a bone disease associated with decreased bone mineral density (BMD) and bone quality factors. Tissue dielectric properties, which can be obtained by thermoacoustic tomography (TAT), are considered as potential parameters correlated with both BMD and bone quality. Therefore, here we propose to use TAT to detect osteoporosis and to monitor the formation of osteoporosis over a long period. Technology or Method: This study used the bilateral ovariectomy to obtain an osteoporotic rat model (n = 4) along with a sham control. During the 100 days after the operation, the right tibia of each rat was in vivo thermoacoustically imaged at 5 time points. After the last TAT imaging, micro computed tomography (Micro-CT) was performed on each rat to validate the TAT findings. Visual observation and semi-quantitative methods were used to analyze the thermoacoustic data. Results: During the monitoring period, the thermoacoustic signal intensity of the tibia of the sham-operated rat continued to increase, while the thermoacoustic signal intensities of the tibia of osteoporotic model rats showed fluctuations. The TAT findings were verified by Micro-CT. Conclusions: Osteoporosis can be clearly detected by TAT. Significant differences in thermoacoustic signal intensities between normal bone growth and osteoporotic bone formation are observed. Clinical or Biological Impact: This study provides initial facts that TAT may become a new tool for noninvasive detection and monitoring of osteoporosis.