Department of Radiology, Abdominal Radiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA.
Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.
Eur Radiol. 2024 Aug;34(8):5131-5141. doi: 10.1007/s00330-023-10560-z. Epub 2024 Jan 8.
To investigate intra-patient variability of iodine concentration (IC) between three different dual-energy CT (DECT) platforms and to test different normalization approaches.
Forty-four patients who underwent portal venous phase abdominal DECT on a dual-source (dsDECT), a rapid kVp switching (rsDECT), and a dual-layer detector platform (dlDECT) during cancer follow-up were retrospectively included. IC in the liver, pancreas, and kidneys and different normalized ICs (NIC:portal vein; NIC:abdominal aorta; NIC:overall iodine load) were compared between the three DECT scanners for each patient. A longitudinal mixed effects analysis was conducted to elucidate the effect of the scanner type, scan order, inter-scan time, and contrast media amount on normalized iodine concentration.
Variability of IC was highest in the liver (dsDECT vs. dlDECT 28.96 (14.28-46.87) %, dsDECT vs. rsDECT 29.08 (16.59-62.55) %, rsDECT vs. dlDECT 22.85 (7.52-33.49) %), and lowest in the kidneys (dsDECT vs. dlDECT 15.76 (7.03-26.1) %, dsDECT vs. rsDECT 15.67 (8.86-25.56) %, rsDECT vs. dlDECT 10.92 (4.92-22.79) %). NIC yielded the best reduction of IC variability throughout all tissues and inter-scanner comparisons, yet did not reduce the variability between dsDECT vs. dlDECT and rsDECT, respectively, in the liver. The scanner type remained a significant determinant for NIC in the pancreas and the liver (F-values, 12.26 and 23.78; both, p < 0.0001).
We found tissue-specific intra-patient variability of IC across different DECT scanner types. Normalization mitigated variability by reducing physiological fluctuations in iodine distribution. After normalization, the scanner type still had a significant effect on iodine variability in the pancreas and liver.
Differences in iodine quantification between dual-energy CT scanners can partly be mitigated by normalization, yet remain relevant for specific tissues and inter-scanner comparisons, which should be taken into account at clinical routine imaging.
• Iodine concentration showed the least variability between scanner types in the kidneys (range 10.92-15.76%) and highest variability in the liver (range 22.85-29.08%). • Normalizing tissue-specific iodine concentrations against the overall iodine load yielded the greatest reduction of variability between scanner types for 2/3 inter-scanner comparisons in the liver and for all (3/3) inter-scanner comparisons in the kidneys and pancreas, respectively. • However, even after normalization, the dual-energy CT scanner type was found to be the factor significantly influencing variability of iodine concentration in the liver and pancreas.
研究三种不同双能 CT（DECT）平台之间碘浓度（IC）的患者内变异性，并测试不同的归一化方法。
回顾性纳入 44 例在癌症随访期间接受门静脉期腹部双源（dsDECT）、快速千伏切换（rsDECT）和双层探测器平台（dlDECT）DECT 的患者。比较每位患者三种 DECT 扫描仪之间的肝、胰腺和肾脏的 IC 以及不同的归一化 IC（NIC：门静脉；NIC：腹主动脉；NIC：总碘负荷）。采用纵向混合效应分析阐明扫描仪类型、扫描顺序、扫描间时间和造影剂用量对归一化碘浓度的影响。
IC 的变异性在肝脏中最高（dsDECT 与 dlDECT 28.96（14.28-46.87）%，dsDECT 与 rsDECT 29.08（16.59-62.55）%，rsDECT 与 dlDECT 22.85（7.52-33.49）%），在肾脏中最低（dsDECT 与 dlDECT 15.76（7.03-26.1）%，dsDECT 与 rsDECT 15.67（8.86-25.56）%，rsDECT 与 dlDECT 10.92（4.92-22.79）%）。NIC 降低了所有组织和扫描仪间比较的 IC 变异性，但分别不能降低 dsDECT 与 dlDECT 和 rsDECT 之间的肝内变异性。扫描仪类型仍然是胰腺和肝脏中 NIC 的显著决定因素（F 值，12.26 和 23.78；均，p<0.0001）。
我们发现不同 DECT 扫描仪类型之间存在特定于组织的患者内 IC 变异性。归一化通过减少碘分布的生理波动来降低变异性。归一化后，扫描仪类型对胰腺和肝脏中的碘变异性仍有显著影响。
双能 CT 扫描仪之间碘定量的差异可以部分通过归一化来缓解，但对于特定组织和扫描仪间比较仍然相关，这在临床常规成像中应加以考虑。
碘浓度在肾脏（范围 10.92-15.76%）中显示出扫描仪类型之间最小的变异性，在肝脏（范围 22.85-29.08%）中显示出最高的变异性。
对特定组织的碘浓度进行归一化，以总碘负荷为基准，降低了 3/3 扫描仪间比较中肝脏和 2/3 扫描仪间比较中肾脏和胰腺的变异性。
然而，即使在归一化后，双能 CT 扫描仪类型仍然是影响肝脏和胰腺中碘浓度变异性的因素。
