Thater Greta, Frerichs Isabel, Büttner Sylvia, Schoenberg Stefan O, Froelich Matthias, Ayx Isabelle
Department of Radiology and Nuclear Medicine, University Medical Centre Mannheim.
Department of Medical Statistics, Biomathematics and Information Processing, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany.
J Thorac Imaging. 2025 Jul 1;40(4):e0822. doi: 10.1097/RTI.0000000000000822.
Computed tomography (CT) is crucial in oncologic imaging for precise diagnosis and staging. Beam-hardening artifacts from contrast media in the superior vena cava can degrade image quality and obscure adjacent structures, complicating lymph node assessment. This study examines the use of virtual monoenergetic reconstruction with photon-counting detector CT (photon-counting CT) to mitigate these artifacts.
The retrospective study included 50 patients who underwent thoracoabdominal scans. Virtual monoenergetic reconstructions at nine keV levels (60 to 140 keV) were analyzed for Hounsfield Unit (HU) stability, image noise, and artifact index in various regions of interest (ROIs): mediastinal adipose tissue (ROI 1 to 3) and vascular stations (ROI 4 to 6) were compared with reference tissue (ROI 7 to 8). The diagnostic image quality of the keV levels was assessed using a 5-point Likert Scale.
Lower keV values (60 to 80) exhibited higher image noise and lower HU stability in mediastinal adipose tissue compared with higher energies, with optimal noise reduction observed at 130 keV (ROI 1 to 3). HU stability in vascular structures (ROI 4 to 6) significantly improved above 80 keV, with the best performance at 140 keV. Artifact levels decreased progressively from 60 to 140 keV. Visually, keV levels of 110 keV (96% Likert ≥4) and 120 keV (60% Likert 4) were rated most diagnostically valuable, consistent with technical findings.
Virtual monoenergetic reconstructions with photon-counting CT effectively reduce beam-hardening artifacts near the superior vena cava, enhancing the visualization of lymph nodes and adjacent structures. This technology advances oncologic imaging by improving diagnostic accuracy in areas previously affected by artifact-related image degradation.
计算机断层扫描（CT）在肿瘤成像中对于精确诊断和分期至关重要。上腔静脉中造影剂产生的束硬化伪影会降低图像质量并模糊相邻结构，使淋巴结评估变得复杂。本研究探讨使用光子计数探测器CT（光子计数CT）进行虚拟单能量重建以减轻这些伪影。
这项回顾性研究纳入了50例行胸腹扫描的患者。分析了九个keV水平（60至140 keV）的虚拟单能量重建在不同感兴趣区域（ROI）的亨氏单位（HU）稳定性、图像噪声和伪影指数：将纵隔脂肪组织（ROI 1至3）和血管部位（ROI 4至6）与参考组织（ROI 7至8）进行比较。使用5点李克特量表评估keV水平的诊断图像质量。
与较高能量相比，较低的keV值（60至80）在纵隔脂肪组织中表现出更高的图像噪声和更低的HU稳定性，在130 keV时观察到最佳降噪效果（ROI 1至3）。血管结构（ROI 4至6）中的HU稳定性在80 keV以上显著改善，在140 keV时性能最佳。伪影水平从60 keV到140 keV逐渐降低。从视觉上看，110 keV（96%李克特量表≥4）和120 keV（60%李克特量表为4）的keV水平被评为最具诊断价值，与技术结果一致。
光子计数CT的虚拟单能量重建有效减少了上腔静脉附近的束硬化伪影，增强了淋巴结和相邻结构的可视化。该技术通过提高先前受伪影相关图像退化影响区域的诊断准确性，推动了肿瘤成像的发展。
