Department of Clinical Physiology Nuclear Medicine and PET, Rigshospitalet Copenhagen University Hospital, Copenhagen, Denmark.
Department of Clinical Medicine, Faculty of Health and Medical Sciences, Copenhagen, Denmark.
Phys Med Biol. 2020 Dec 3;65(24). doi: 10.1088/1361-6560/abc366.
Metal artefacts in PET/CT images hamper diagnostic accuracy in head and neck cancer (HNC). The aim of this study is to characterise the clinical effects of metal artefacts on PET/CT in HNC and to inform decision-making concerning implementation of MAR techniques. We study a combined dual energy CT and inpainting-based metal artefact reduction (DECT-I-MAR) technique for PET/CT in three settings: (A) A dental phantom with a removable amalgam-filled tooth to evaluate the PET error in comparison to a known reference. (B) PET-positive patients with metallic implants to demonstrate the relationship between CT metal artefacts and PET error. (C) Metabolic tumour volumes delineated in PET-positive patients with metal implants to evaluate the clinical impact. In (A) DECT-I-MAR reduced the PET error significantly. In (B) we demonstrate an increasing PET error with increasing CT artefact severity in patients. In (C) it is shown that the presence of artefacts in the same axial slices as the tumour significantly decreases biomarker stability and increase delineation variability. This work shows the practical feasibility of DECT-I-MAR-based PET/CT imaging, and indicates a positive clinical impact of using the technique routinely for HNC patients. The impact of CT artefacts on PET is considerable, especially in workflows where quantitative PET biomarkers and tumour volumes are used. In such cases, and for patients with tumours in proximity of metals, we recommend that a MAR technique for PET/CT is employed.
金属伪影会降低头颈部癌症（HNC）患者正电子发射断层扫描/计算机断层扫描（PET/CT）的诊断准确性。本研究旨在分析金属伪影对 HNC 患者 PET/CT 的临床影响，并为决定是否应用金属伪影减少（MAR）技术提供依据。我们研究了一种联合应用双能 CT 和基于图像修复的金属伪影减少（DECT-I-MAR）技术的 PET/CT，该技术应用于以下三种情况：（A）使用带可移除汞合金填充牙的牙科模型来评估与已知参考值相比的 PET 误差。（B）有金属植入物的 PET 阳性患者，以显示 CT 金属伪影与 PET 误差之间的关系。（C）有金属植入物的 PET 阳性患者的代谢肿瘤体积的勾画，以评估临床影响。（A）中，DECT-I-MAR 显著降低了 PET 误差。（B）中，我们在患者中证明了 CT 伪影严重程度与 PET 误差呈正相关。（C）表明肿瘤所在轴向切片存在伪影会显著降低生物标志物的稳定性，并增加勾画的变异性。这项工作表明基于 DECT-I-MAR 的 PET/CT 成像具有实际可行性，并表明在 HNC 患者中常规使用该技术具有积极的临床影响。CT 伪影对 PET 的影响相当大，尤其是在使用定量 PET 生物标志物和肿瘤体积的工作流程中。在这种情况下，对于肿瘤靠近金属的患者，我们建议使用 MAR 技术进行 PET/CT。
