An Experimental Study Of Dual Source CT Approach Measuring Bone Mineral Density

An Experimental Study of Dual Source CT Approach Measuring Bone Mineral Density AbstractObjectiveThere are many bone diseases which need measure the bone mineral density, especially with an aging population, the incidence of osteoporotic fractures gradually increased, therefore, choose the appropriate means of early detection of osteoporosis checks loose, prediction of fracture become the core of gerontology. The number of bone tissue abnormalities and structural change is difficult to direct detection, Measuring bone mineral density to detect abnormal bone tissue is the greater use of the clinical method. Currently used clinically in BMD measurement methods are mainly dual-energy X-ray absorptiometry measurement(DEXA) and single-energy quantitative CT measurements (SEQCT), but there exist some defects in these two methods, the measurement value and the true value between these two methods exist the big errors. In this study, based on fully understand the principle of dual energy bone density measurement, we designed and developed the BMD measurement software of DEQCT applying at the Siemens dual source CT(DSCT). We measured the BMD values of the goal phantoms with different content of calcium phosphate and porcine vertebral body in vitro compare with the measuring values of SEQCT and DXA. To evaluate the accuracy of DEQCT's approach measuring BMD at Dual source CT. so as to provide a better way of BMD measurement.Materials and methodsExperiment 1:Using calcium phosphate, collagen, fat and water made 5 phantoms imitation of human lumbar cancellous bone, which volume is 200cm3. The content of calcium phosphate is 0mg/cm3,50mg/cm3,100mg/cm3,150mg/cm3,200mg/cm3, respectively. Siemens DSCT was used to scan the phantoms through dual-energy and single-energy method, and then the image reconstruction, the reconstructed dual-energy images were loaded in dual-energy software or SEQCT software of Neu-soft group's for DEQCT or SEQCT bone mineral density measurement, the results were compared, through one-way ANOVA and linear regression analysis.Experiment 2:Six fresh porcine spine commercially available, and each have 5 vertebrae body, the first application of dual-energy DEXA for bone density measurements, and then apply the dual-source CT scan the porcine spine for DEQCT and SEQCT BMD measurement. Reconstructed image were loaded in software to measure each vertebral body BMD, at the same time recording single-energy 140kv bone mineral density values. Finally remove the soft tissue on the spine, separating out the 30 vertebral body, Archimede's law was used to measure the volume of each vertebral body. Then muffle furnace was used to calcined each vertebral body, and then weighed the ash weight values. The above three kinds of measurement methods'results were compared by single-factor variance analysis.ResultsIn experiment 1 the BMD values measured by DEQCT method are closest to the true value, the difference between the measured values and the true vales does not have a statistically significant (p<0.05). Compared with SEQCT with correct phantom, the BMD values of SEQCT140kv is closer to the true value. and the difference between the two does not have a statistically significant (p<0.05). Using the linear regression method,we can see the slope and the intercept of the straight line derived from DEQCT are closest to the straight line's derived from real value'. While the two kinds of SEQCT'S method has a greater margin of error. At the same time DEQCT method's deviation (6.5%) was significantly smaller than the other two kinds of SEQCT method (SEQCT140kv 31.07%, SEQCT with correct phantom 62.04%), and 22 difference was statistically significant (p<0.05).In experiment 2, Compared the SEQCT140KV and DXA, the DEQCT's value is closest to the value of ash weight, and the difference between the DEQCT value and ash weight value does not have a statistically significant (p= 0.78). But compared with the SEQCT140kv and DEXA. The differences were significant (p=0.029 and p＜0.001). The SEQCT140kv method's value is less than the ash weight density, but the value is more than the value of DEXA, the difference between the two method was significant (p=0.003).ConclusionBMD measurement of DEQCT at DSCT can improve the current measurement method's deficiency. Compared with the SEQCT and DEXA, the measurement values is closer to the true values. It is able to provide more accurate bone density measurement for clinical practice.