Investigation of Bone Mineral Density at Vertebral Bodies in X-ray CT Images

Abstract

The number of osteoporosis patients is increasing every year in Japan. Multi-detector-row CT is widely used in clinical environment including diagnoses of osteoporosis. However, quantitative evaluation of osteoporosis based on CT images is not defined. This paper investigates the distribution of bone mineral density (BMD) values measured in vertebral trabecular bones from the twelfth thoracic vertebra to the first sacral vertebra in Japanese subjects. Using X-ray CT images of 136 subjects, CT number of vertebral trabecular bones in these regions was measured, and BMD values were estimated from CT number using a bone mineral reference phantom. In addition, the relation of BMD values of each vertebra was investigated, and correlation with age, gender, and fusion at lumbosacral portion was shown. The present study showed that there was no statistical significant difference in BMD values of vertebral trabecular bones from the twelfth thoracic vertebra to the fifth lumbar vertebra. Therefore, among these vertebrae, if the CT number of one vertebra is known, the BMD values of the other vertebrae can be estimated based on the relationships shown by our research.