Panta Raj Kumar, Yin Zhye, Grönberg Fredrik, Bhattarai Mridul, Abadi Ehsan, Segars Paul, Samei Ehsan
Carl E. Ravin Advanced Imaging Laboratories and Center for Virtual Imaging Trials, 2424 Erwin Rd, Suite 302, Durham, NC 27705, USA; Department of Radiology, Duke University, 2301 Erwin Rd, Durham, NC 27705, USA.
GE Healthcare, 3000 N Grandview Blvd, Waukesha, WI 53188, USA.
Phys Med. 2025 Jul;135:105003. doi: 10.1016/j.ejmp.2025.105003. Epub 2025 Jun 6.
This study investigates the imaging performance of a deep silicon-based photon-counting CT (Si-PCCT) in quantifying iodine contrast through a virtual imaging trial (VIT).
We developed a VIT framework using Si-PCCT simulator and benchmarked it against a prototype using an ACR phantom for assessing spatial resolution and noise characteristics, and a geometric phantom for iodine quantification. We imaged geometrical phantoms (20 - 40 cm) with iodine concentrations ranging from 1 to 19.7 mg/ml and XCAT human models with iodine contrast at BMI of 19 to 38 kg/m across different radiation dose levels (13.9, 27.8, and 41.7 mGy of CTDI). We performed material decomposition, reconstructed iodine CT images, and evaluated iodine quantification accuracy.
The Si-PCCT simulator closely matched with the prototype, with differences within 3 % in MTF (f and f) and 3.7 % (f) in NNPS, and Root-Mean-Square Error of 0.12 mg/ml in iodine quantification. The mean absolute errors (MAE) between the estimated and ground-truth iodine concentration were 0.10, 0.25, and 1.80 mg/ml for 20, 30, and 40 cm phantoms, and 0.31, 0.37, and 0.70 mg/ml for XCAT human models with BMIs of 19, 28, and 38 kg/m, respectively. Similarly, the MAEs were 0.88, 0.45, and 0.31 mg/ml for the geometrical phantoms, and 0.66, 0.5, and 0.46 mg/ml for human models at CTDI of 13.9, 27.8, and 41.7 mGy respectively. These results demonstrate accurate iodine quantification performance, influenced by object size and radiation dose.
This study shows the promising clinical utility of Si-PCCT for accurate iodine quantification under clinically relevant imaging conditions.
本研究通过虚拟成像试验（VIT）研究基于深度硅的光子计数CT（Si-PCCT）在碘造影剂定量方面的成像性能。
我们使用Si-PCCT模拟器开发了一个VIT框架，并使用ACR体模评估空间分辨率和噪声特性，以及使用几何体模进行碘定量，将其与一个原型进行基准测试。我们对碘浓度范围为1至19.7mg/ml的几何体模（20 - 40cm）以及体重指数为19至38kg/m²且具有碘造影剂的XCAT人体模型在不同辐射剂量水平（CTDI为13.9、27.8和41.7mGy）下进行成像。我们进行了物质分解，重建碘CT图像，并评估碘定量准确性。
Si-PCCT模拟器与原型紧密匹配，调制传递函数（MTF，f和f）差异在3%以内，噪声功率谱（NNPS，f）差异在3.7%以内，碘定量的均方根误差为0.12mg/ml。对于20cm、30cm和40cm的体模，估计碘浓度与真实碘浓度之间的平均绝对误差（MAE）分别为0.10、0.25和1.80mg/ml；对于体重指数分别为19、28和38kg/m²的XCAT人体模型，MAE分别为0.31、0.37和0.70mg/ml。同样，对于几何体模，在CTDI为13.9、27.8和41.7mGy时，MAE分别为0.88、0.45和0.31mg/ml；对于人体模型，MAE分别为0.66、0.5和0.46mg/ml。这些结果表明碘定量性能准确，受物体大小和辐射剂量影响。
本研究表明Si-PCCT在临床相关成像条件下进行准确碘定量具有良好的临床应用前景。
