Accuracy of densitometry of two cone beam computed tomography equipment in comparison with computed tomography

摘要

Background: The use of oral implants has been growing, and cone beam computerized tomography (CBCT) hasbecome the method of choice for oral and maxillofacial radiology.Objective: To assess the accuracy of bone densitometry in two different CBCT devices in comparison withMDCT (multi-detector CT).Methods: Different concentrations of urografin, including 2.5%, 5%, 7.5%, 10%, 12.5%, were prepared, and theHounsfield unit of these solution was measured by two CBCT devices (SORDEX CRANEX 3D and NEWTOM5G) and one spiral CT device (SOMATOM SENSATION). Difference of output Hounsfield units in eachconcentration was compared in three devices. Correlation of devices with increase of urografin dose also wasevaluated. Statistical analyses of the data were performed using SPSS18 and Kruskal–Wallis and Mann–WhitneyU tests, along with Spearman’s correlation coefficient.Results: The range of gray density for NEWTOM 5G CBCT, SORDEX 3D CBCT, and SOMATOM CTimaging systems was from 781 to 2311, 427 to 1464, and 222 to 994, respectively. There was significantdifference between devices in the Hounsfield unit in all urografin concentrations (p<0.001). Also there was asignificant correlation between three devices with increasing the urografin dose (p0.95)Conclusion: Our findings indicated a high correlation and linear relationship between different studied imagingsystems. Although utilizing CBCT in the assessment of bone density is useful according to its lower emitted doseand less cost, clinicians should be aware of the issue that the voxel value in CBCT is not as perfect as CT.