Department of Radiology, Mayo Clinic, Rochester, MN, United States of America.
Siemens Medical Solutions USA, Malvern, PA, United States of America.
Phys Med Biol. 2024 Nov 12;69(22). doi: 10.1088/1361-6560/ad8da1.
To assess the accuracy and stability of areal bone-mineral-density (aBMD) measurements from multi-energy CT localizer radiographs acquired using photon-counting detector (PCD) CT.A European Spine Phantom (ESP) with hydroxyapatite (HA 0.5, 1.0 and 1.5 g cm) was scanned using clinical PCD-CT and a dual-energy x-ray absorptiometry (DXA) to compare aBMD values. To assess aBMD stability and reproducibility, PCD-localizers were acquired twice a day for one week, and once per week for five weeks. Multiple ESP anteroposterior thicknesses (18, 26, 34, and 40 cm) were achieved using a synthetic gel layer and scanned across eight tube current values for both 120 kV (15-120 mA) and 140 kV (10-80 mA). One-way analysis of variance was performed for statistical significance (< 0.05 considered significant). Quantitative HA and water maps were reconstructed using a prototype material-decomposition software, and aBMD was calculated after background correction.performance of PCD-based aBMD was illustrated using a patient scan acquired at 140 kV and 40 mA, and lumbar aBMD values were compared with DXA.The ESP aBMD values from PCD-localizers demonstrated excellent day-to-day stability with a coefficient-of-variation ranging from 0.42% to 0.53%, with mean absolute percentage errors (MAPE) of less than 5% for all three vertebral bodies. The coefficient-of-variation for weekly scans ranged from 0.17% to 0.60%, again with MAPE below 5% for all three vertebral bodies. Across phantom sizes and tube currents, the MAPE values varied ranging from 1.84% to 13.78% for 120 kV, and 1.38%-9.11% for 140 kV. No significant difference was found between different tube currents. For the standard phantom size, DXA showed 11.21% MAPE whereas PCD-CT showed 3.04% MAPE. For the patient scan, deviation between PCD-based aBMD values and those obtained from DXA ranged from 0.07% to 9.82% for different lumbar vertebra.This study highlights the accuracy and stability of PCD-CT localizers for measuring aBMD. We demonstrated aBMD accuracy across different sizes and showed that higher radiation doses did not inherently increase aBMD accuracy.
评估基于多能量 CT 定位器射线照片的体骨矿物质密度（aBMD）测量的准确性和稳定性，这些射线照片是使用光子计数探测器（PCD）CT 采集的。使用临床 PCD-CT 和双能 X 射线吸收法（DXA）对具有羟磷灰石（HA 0.5、1.0 和 1.5 g cm）的欧洲脊柱模型（ESP）进行扫描，以比较 aBMD 值。为了评估 aBMD 的稳定性和可重复性，每天两次在一周内采集 PCD 定位器，每周一次采集五周。使用合成凝胶层实现多个 ESP 前后厚度（18、26、34 和 40 cm），并针对 120 kV（15-120 mA）和 140 kV（10-80 mA）对八个管电流值进行扫描。使用原型材料分解软件对单向方差分析进行统计显着性检验（<0.05 视为显着）。使用在 140 kV 和 40 mA 采集的患者扫描来演示基于 PCD 的 aBMD 的性能，并将腰椎 aBMD 值与 DXA 进行比较。PCD-定位器的 ESP aBMD 值显示出出色的日常稳定性，变异系数范围为 0.42%至 0.53%，所有三个椎体的平均绝对百分比误差（MAPE）均小于 5%。每周扫描的变异系数范围为 0.17%至 0.60%，所有三个椎体的 MAPE 再次低于 5%。在整个体模尺寸和管电流范围内，120 kV 的 MAPE 值变化范围为 1.84%至 13.78%，140 kV 的 MAPE 值变化范围为 1.38%至 9.11%。不同管电流之间没有发现显着差异。对于标准体模尺寸，DXA 显示 11.21%MAPE，而 PCD-CT 显示 3.04%MAPE。对于患者扫描，PCD 基于 aBMD 值与 DXA 获得的值之间的偏差范围为 0.07%至 9.82%，用于不同的腰椎。本研究强调了 PCD-CT 定位器测量 aBMD 的准确性和稳定性。我们展示了跨不同尺寸的 aBMD 准确性，并表明更高的辐射剂量不会固有地增加 aBMD 准确性。
