Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada.
Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada.
Med Eng Phys. 2020 Apr;78:55-63. doi: 10.1016/j.medengphy.2020.01.009. Epub 2020 Feb 12.
CT-based opportunistic skeletal assessment complements current osteoporosis diagnosis. Quantitative assessment by internal density calibration overcomes the limitations of phantom-based calibration. We sought to establish and validate an internal calibration technique using abdominal CT scans and establish reproducibility precision for three density calibration techniques. Ten full-body cadavers were CT scanned at the spine and pelvis with a calibration phantom. Internal calibration was performed using in-scan tissue references and deriving a voxel-specific calibration. Bone mineral density (BMD) and finite element (FE) failure load assessed skeletal health. Three independent users measured intra-exam precision by manual tissue selection. To verify results, ten subjects were imaged using an abdominal imaging protocol. Internal calibration performed equivalently to gold-standard phantom-based calibration in the cadaver spine and hip. Internal calibration BMD precision in the spine was 7 mg/cc (4.9%) and FE precision was 163 N (7.2%), whereas phantom-based precision was 3 mg/cc (1.8%) and 77 N (3.8%). Internal calibration hip BMD and FE precision was 11 mg/cc (5.3%) and 84 N (6.0%), whereas phantom-based precision was 2 mg/cc (1.3%) and 30 N (3.4%). Using the abdominal imaging protocol, internal calibration performed comparably to phantom-based calibration. Internal calibration provides BMD and FE outcome precision within 7.2% for opportunistic skeletal health assessment.
基于 CT 的机会性骨骼评估补充了当前的骨质疏松症诊断。通过内部密度校准的定量评估克服了基于体模校准的局限性。我们旨在建立和验证一种使用腹部 CT 扫描的内部校准技术，并为三种密度校准技术建立可重复性精度。十个全身尸体在脊柱和骨盆处进行 CT 扫描，并使用校准体模进行扫描。内部校准使用扫描内组织参考值，并得出特定体素的校准值。骨矿物质密度（BMD）和有限元（FE）失效负载评估骨骼健康。三位独立用户通过手动组织选择测量了内部检查精度。为了验证结果，对十个受试者使用腹部成像方案进行了成像。在尸体脊柱和臀部，内部校准与金标准体模校准等效。脊柱内校准 BMD 精度为 7mg/cc（4.9%），FE 精度为 163N（7.2%），而基于体模的精度为 3mg/cc（1.8%）和 77N（3.8%）。臀部内校准 BMD 和 FE 精度为 11mg/cc（5.3%）和 84N（6.0%），而基于体模的精度为 2mg/cc（1.3%）和 30N（3.4%）。使用腹部成像方案，内部校准与基于体模的校准表现相当。内部校准为机会性骨骼健康评估提供了 BMD 和 FE 结果精度在 7.2%以内。
