PDF(Pubmed)
Abstract：
BACKGROUND: Lower extremity peripheral artery disease frequently presents with calcifications which reduces the accuracy of computed tomography (CT) angiography, especially below-the-knee. Photon-counting detector (PCD)-CT offers improved spatial resolution and less calcium blooming. We aimed to identify the optimal reconstruction parameters for PCD-CT angiography of the lower legs.
METHODS: Tubes with different diameters (1-5 mm) were filled with different iodine concentrations and scanned in a water container. Images were reconstructed with 0.4 mm isotropic resolution using a quantitative kernel at all available sharpness levels (Qr36 to Qr76) and using different levels of quantum iterative reconstruction (QIR-2-4). Noise and image sharpness were determined for all reconstructions. Additionally, CT angiograms of 20 patients, reconstructed with a medium (Qr44), sharp (Qr60), and ultrasharp (Qr72) kernel at QIR-2-4, were evaluated by three readers assessing noise, delineation of plaques and vessel walls, and overall quality.
RESULTS: In the phantom study, increased kernel sharpness led to higher image noise (e.g., 16, 38, 77 HU for Qr44, Qr60, Qr72, and QIR-3). Image sharpness increased with increasing kernel sharpness, reaching a plateau at the medium-high level 60. Higher QIR levels decreased image noise (e.g., 51, 38, 25 HU at QIR-2-4 and Qr60) without reducing vessel sharpness. The qualitative in vivo results confirmed these findings: the sharp kernel (Qr60) with the highest QIR yielded the best overall quality.
CONCLUSIONS: The combination of a sharpness level optimized reconstruction kernel (Qr60) and the highest QIR level yield the best image quality for PCD-CT angiography of the lower legs when reconstructed at 0.4-mm resolution.
CONCLUSIONS: Using high-resolution PCD-CT angiography with optimized reconstruction parameters might improve diagnostic accuracy and confidence in peripheral artery disease of the lower legs.
CONCLUSIONS: Effective exploitation of the potential of PCD-CT angiography requires optimized reconstruction parameters. Too soft or too sharp reconstruction kernels reduce image quality. The highest level of quantum iterative reconstruction provides the best image quality.
METHODS: Tubes with different diameters (1-5 mm) were filled with different iodine concentrations and scanned in a water container. Images were reconstructed with 0.4 mm isotropic resolution using a quantitative kernel at all available sharpness levels (Qr36 to Qr76) and using different levels of quantum iterative reconstruction (QIR-2-4). Noise and image sharpness were determined for all reconstructions. Additionally, CT angiograms of 20 patients, reconstructed with a medium (Qr44), sharp (Qr60), and ultrasharp (Qr72) kernel at QIR-2-4, were evaluated by three readers assessing noise, delineation of plaques and vessel walls, and overall quality.
RESULTS: In the phantom study, increased kernel sharpness led to higher image noise (e.g., 16, 38, 77 HU for Qr44, Qr60, Qr72, and QIR-3). Image sharpness increased with increasing kernel sharpness, reaching a plateau at the medium-high level 60. Higher QIR levels decreased image noise (e.g., 51, 38, 25 HU at QIR-2-4 and Qr60) without reducing vessel sharpness. The qualitative in vivo results confirmed these findings: the sharp kernel (Qr60) with the highest QIR yielded the best overall quality.
CONCLUSIONS: The combination of a sharpness level optimized reconstruction kernel (Qr60) and the highest QIR level yield the best image quality for PCD-CT angiography of the lower legs when reconstructed at 0.4-mm resolution.
CONCLUSIONS: Using high-resolution PCD-CT angiography with optimized reconstruction parameters might improve diagnostic accuracy and confidence in peripheral artery disease of the lower legs.
CONCLUSIONS: Effective exploitation of the potential of PCD-CT angiography requires optimized reconstruction parameters. Too soft or too sharp reconstruction kernels reduce image quality. The highest level of quantum iterative reconstruction provides the best image quality.
摘要：
背景：下肢外周动脉疾病常伴有钙化，这降低了计算机断层扫描（CT）血管造影的准确性，尤其是膝盖以下.光子计数探测器(PCD)-CT提供改进的空间分辨率和更少的钙溢出。我们旨在确定小腿PCD-CT血管造影的最佳重建参数。
方法：用不同的碘浓度填充不同直径（1-5mm）的管，并在水容器中扫描。在所有可用的清晰度水平(Qr36至Qr76)下使用定量内核并使用不同水平的量子迭代重建(QIR-2-4)以0.4mm各向同性分辨率重建图像。确定所有重建的噪声和图像清晰度。此外,20例患者的CT血管造影,用介质（QR44）重建，夏普（Qr60），和超声（Qr72）内核在QIR-2-4，由三个读者评估噪声，斑块和血管壁的轮廓，和整体质量。
结果：在幻影研究中，增加的内核清晰度导致更高的图像噪声(例如，Qr44、Qr60、Qr72和QIR-3的16、38、77HU)。图像清晰度随着内核清晰度的增加而增加，达到中高水平60的高原。较高的QIR水平降低了图像噪声(例如，在QIR-2-4和Qr60处的51、38、25HU）没有降低血管锐度。体内定性结果证实了这些发现：具有最高QIR的锋利内核（Qr60）产生了最佳的整体质量。
结论：当在0.4mm分辨率下重建时，锐度级别优化的重建内核（Qr60）和最高QIR级别的组合可产生最佳的下肢PCD-CT血管造影图像质量。
结论：使用具有优化重建参数的高分辨率PCD-CT血管造影可能会提高下肢外周动脉疾病的诊断准确性和置信度。
结论：有效利用PCD-CT血管造影的潜力需要优化重建参数。太软或太尖锐的重建内核降低图像质量。最高水平的量子迭代重建提供最佳图像质量。
方法：用不同的碘浓度填充不同直径（1-5mm）的管，并在水容器中扫描。在所有可用的清晰度水平(Qr36至Qr76)下使用定量内核并使用不同水平的量子迭代重建(QIR-2-4)以0.4mm各向同性分辨率重建图像。确定所有重建的噪声和图像清晰度。此外,20例患者的CT血管造影,用介质（QR44）重建，夏普（Qr60），和超声（Qr72）内核在QIR-2-4，由三个读者评估噪声，斑块和血管壁的轮廓，和整体质量。
结果：在幻影研究中，增加的内核清晰度导致更高的图像噪声(例如，Qr44、Qr60、Qr72和QIR-3的16、38、77HU)。图像清晰度随着内核清晰度的增加而增加，达到中高水平60的高原。较高的QIR水平降低了图像噪声(例如，在QIR-2-4和Qr60处的51、38、25HU）没有降低血管锐度。体内定性结果证实了这些发现：具有最高QIR的锋利内核（Qr60）产生了最佳的整体质量。
结论：当在0.4mm分辨率下重建时，锐度级别优化的重建内核（Qr60）和最高QIR级别的组合可产生最佳的下肢PCD-CT血管造影图像质量。
结论：使用具有优化重建参数的高分辨率PCD-CT血管造影可能会提高下肢外周动脉疾病的诊断准确性和置信度。
结论：有效利用PCD-CT血管造影的潜力需要优化重建参数。太软或太尖锐的重建内核降低图像质量。最高水平的量子迭代重建提供最佳图像质量。
