Ter Voert Edwin E G W, Veit-Haibach Patrick, Ahn Sangtae, Wiesinger Florian, Khalighi M Mehdi, Levin Craig S, Iagaru Andrei H, Zaharchuk Greg, Huellner Martin, Delso Gaspar
Department of Nuclear Medicine, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland.
University of Zurich, Zurich, Switzerland.
Eur J Nucl Med Mol Imaging. 2017 Jul;44(7):1223-1233. doi: 10.1007/s00259-017-3619-2. Epub 2017 Jan 26.
Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning.
A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact).
A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p < 0.01) indicating that artifacts were less noticeable when TOF information was included.
Our study indicates that PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants.
我们的目标是在临床中确定飞行时间（TOF）信息在减少PET伪影以及提高同时进行的TOF PET/MR扫描中PET图像质量和准确性方面的价值。
纳入了总共65例在同时进行的TOF PET/MR扫描仪中接受对比扫描的患者。重建TOF和非TOF PET图像，进行临床检查、比较并评分。PET成像伪影分为与植入物相关的大或小伪影、与牙种植体相关的伪影以及与植入物无关的伪影。使用从0（无伪影）到4（严重伪影）的量表评估图像质量差异，尤其是与（植入物）伪影相关的差异。
共发现并评估了87个图像伪影。4例患者有与植入物相关的大伪影，8例患者有小伪影，27例患者有牙种植体/填充物，48例患者有与植入物无关的伪影。非TOF PET图像的平均评分为1.14±0.82，TOF图像的平均评分为0.53±0.66（p<0.01），这表明包含TOF信息时伪影不太明显。
我们的研究表明，在同时进行的PET/MR中整合TOF信息可显著减轻PET图像伪影。这种影响在因金属植入物而有明显伪影的患者中最为明显。
