Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany (D.G., L.M., M.C.H., F.S., C.D., Y.Y., T.E., R.K.).
Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany (D.G., L.M., M.C.H., F.S., C.D., Y.Y., T.E., R.K.).
Acad Radiol. 2023 Sep;30 Suppl 1:S143-S154. doi: 10.1016/j.acra.2023.03.026. Epub 2023 Apr 22.
Hepatocellular carcinoma (HCC) is the only tumor entity that allows non-invasive diagnosis based on imaging without further histological proof. Therefore, excellent image quality is of utmost importance for HCC diagnosis. Novel photon-counting detector (PCD) CT improves image quality via noise reduction and higher spatial resolution, inherently providing spectral information. The aim of this study was to investigate these improvements for HCC imaging with triple-phase liver PCD-CT in a phantom and patient population study focusing on identification of the optimal reconstruction kernel.
Phantom experiments were performed to analyze objective quality characteristics of the regular body and quantitative reconstruction kernels, each with four sharpness levels (36-40-44-48). For 24 patients with viable HCC lesions on PCD-CT, virtual monoenergetic images at 50 keV were reconstructed using these kernels. Quantitative image analysis included contrast-to-noise ratio (CNR) and edge sharpness. Three raters performed qualitative analyses evaluating noise, contrast, lesion conspicuity, and overall image quality.
In all contrast phases, the CNR was highest using the kernels with a sharpness level of 36 (all p < 0.05), with no significant influence on lesion sharpness. Softer reconstruction kernels were also rated better regarding noise and image quality (all p < 0.05). No significant differences were found in image contrast and lesion conspicuity. Comparing body and quantitative kernels with equal sharpness levels, there was no difference in image quality criteria, neither regarding in vitro nor in vivo analysis.
Soft reconstruction kernels yield the best overall quality for the evaluation of HCC in PCD-CT. As the image quality of quantitative kernels with potential for spectral post-processing is not restricted compared to regular body kernels, they should be preferred.
肝细胞癌（HCC）是唯一一种可以通过影像学检查进行非侵入性诊断的肿瘤实体，无需进一步的组织学证实。因此，对于 HCC 诊断来说，卓越的图像质量至关重要。新型光子计数探测器（PCD）CT 通过降低噪声和提高空间分辨率来改善图像质量，同时还提供了光谱信息。本研究旨在通过在体模和患者人群中进行三时相肝脏 PCD-CT 研究，探讨这些改进对 HCC 成像的影响，重点关注最佳重建核的选择。
体模实验用于分析常规体模和定量重建核的客观质量特征，每个核均具有四个锐利度级别（36-40-44-48）。对 24 例 PCD-CT 上有存活 HCC 病变的患者进行了研究，使用这些核在 50keV 下重建虚拟单能量图像。定量图像分析包括对比噪声比（CNR）和边缘锐利度。三位观察者进行了定性分析，评估了噪声、对比度、病变显著性和整体图像质量。
在所有对比阶段，使用锐利度级别为 36 的核时，CNR 最高（均 p<0.05），但对病变锐利度无显著影响。较软的重建核在噪声和图像质量方面的评价也更好（均 p<0.05）。图像对比度和病变显著性无显著差异。在体模和定量核之间比较相同锐利度水平的核，在体外和体内分析中，图像质量标准均无差异。
在 PCD-CT 评估 HCC 时，软重建核可获得最佳的整体质量。由于具有光谱后处理潜力的定量核的图像质量不受限制，因此与常规体模核相比，应优先选择定量核。
