Rybertt Martin V, Liu Leening P, Sahbaee Pooyan, Nowak Tristan, Mathew Manoj, Litt Harold I, Cormode David P, Dhanaliwala Ali H, Noël Peter B
Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
medRxiv. 2025 Aug 24:2025.08.21.25333798. doi: 10.1101/2025.08.21.25333798.
To evaluate the feasibility and performance of K-edge imaging of iodine (I) and gadolinium (Gd) on a clinically available photon-counting computed tomography (PCCT) system.
A dual-source clinical PCCT scanner with four energy thresholds (20, 55, 72, 90 keV) was used to scan phantoms containing pure and mixed solutions of I and Gd across multiple concentrations (1-10 mg/mL) and radiation doses (1-8 mGy). Multi-material decomposition was performed using a calibration-based, image-domain algorithm to generate material-specific maps. Quantitative accuracy was assessed using Bland-Altman analysis and contrast-to-noise ratio (CNR), while noise and bias trends were statistically analyzed using non-parametric tests.
K-edge imaging was successfully achieved on a clinical PCCT system with accurate decomposition of I and Gd across varying concentrations, solution types (pure/mixed), and dose levels. Quantitative bias was significantly influenced by radiation dose, concentration, and solution type (p < 0.0004). Increased radiation dose and contrast concentration improved quantification accuracy, with maximum bias reductions of 0.9 (I) and 0.3 mg/mL (Gd). CNR correlated linearly with concentration (R > 0.99) and moderately with dose (R = 0.85-0.94), achieving peak values of 13 (I) and 16 (Gd) at 8 mGy. Mixed solutions showed reduced performance compared to pure solutions, i.e., CNR of 5 mg/mL Gd solutions increased by 0.6 per mGy in pure solutions while by 0.5 per mGy in mixtures. Noise was dependent on dose but not on concentration or solution type.
This study establishes the feasibility of K-edge imaging using a clinical PCCT system and demonstrates accurate, simultaneous decomposition of I and Gd in pure and mixed solutions. These findings support the clinical translation of K-edge imaging and highlight PCCT's potential for advanced dual-contrast and molecular imaging applications.
评估在临床可用的光子计数计算机断层扫描（PCCT）系统上进行碘（I）和钆（Gd）的K边成像的可行性和性能。
使用具有四个能量阈值（20、55、72、90 keV）的双源临床PCCT扫描仪，对含有不同浓度（1-10 mg/mL）和辐射剂量（1-8 mGy）的I和Gd纯溶液及混合溶液的体模进行扫描。使用基于校准的图像域算法进行多物质分解，以生成特定物质的图像。使用Bland-Altman分析和对比噪声比（CNR）评估定量准确性，同时使用非参数检验对噪声和偏差趋势进行统计分析。
在临床PCCT系统上成功实现了K边成像，能够在不同浓度、溶液类型（纯/混合）和剂量水平下准确分解I和Gd。定量偏差受辐射剂量、浓度和溶液类型的显著影响（p < 0.0004）。增加辐射剂量和造影剂浓度可提高定量准确性，I的最大偏差降低0.9，Gd的最大偏差降低0.3 mg/mL。CNR与浓度呈线性相关（R > 0.99），与剂量呈中度相关（R = 0.85 - 0.94），在8 mGy时I和Gd的CNR峰值分别为13和16。与纯溶液相比，混合溶液的性能有所下降，即纯溶液中5 mg/mL Gd溶液的CNR每mGy增加0.6，而混合溶液中每mGy增加0.5。噪声取决于剂量，而不取决于浓度或溶液类型。
本研究证实了使用临床PCCT系统进行K边成像的可行性，并证明了在纯溶液和混合溶液中准确、同时分解I和Gd。这些发现支持K边成像的临床转化，并突出了PCCT在先进的双对比和分子成像应用中的潜力。
