Quantitative Assessment of Vertebral Mineral Content by Dual-energy Computed Tomography.

Research Project

Project/Area Number	60570475
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Radiation science
Research Institution	Toyama Medical & Pharmaceutical University
Principal Investigator	SETO Hikaru Toyama Medical & Pharmaceutical University, 医学部, 助教授 (20019962)
Co-Investigator(Kenkyū-buntansha)	KAMEI Tetuya Toyama Medical & Pharmaceutical University, 医学部・放射線医学教室, 講師 (10143851)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Computed tomography / Dual-energy technique / Single-energy technique / 骨塩量 / シングルエネルギー法
Research Abstract	The influences of the vertebral fat content and human torso size on CT densitometry for bone mineral content (BMC) were measured by single-and dual-energy computed tomography, using the human torso phantoms made of uretan, in which various concentrations of potassium phosphate ( <K_2HPO_4> ) solutions were inserted as a vertebral cancellous bone. Single-energy CT at 120 kVp is better in quality of the image than that at 80 kVp. However, single-energy CT overestimated BMC by 11.8% as the size of human torso decreased, and consistently underestimated BMC by 14.2% as the fat volume increased up to 25% at 150mg/ml of <K_2HPO_4> solution. Dual-energy CT (120 and 80 kVp) was not significantly affected by the fat volume in potassium phosphate solutions. Absolute error of BMC measurement was <-!+> 10mg/ml <K_2HPO_4> equivalent by dual-energy CT. However reproducibility of single-energy CT is better than dual-energy CT. Therefore, single-energy CT is first of choice to screen the patients suspected of metabolic bone disease despite of the underestimation of BMC measurement.