Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
Ann Nucl Med. 2022 Aug;36(8):736-745. doi: 10.1007/s12149-022-01756-2. Epub 2022 May 28.
Shine-though artifact can appear as regions with falsely increased uptake in the immediate vicinity of large hot sources in F-FDG PET/CT. This artifact may adversely affect the assessment of tumor involvement in the regions adjacent to the bladder. The purpose of this study was to evaluate the prevalence of shine-through artifacts in clinical F-FDG PET/CT examinations and the factors that can influence their occurrence and extent.
PET/CT images were acquired with Discovery PET/CT 690. One hundred six patients who underwent F-FDG PET/CT for clinical purposes were retrospectively reviewed. PET images were reconstructed using 3-dimensional ordered-subset expectation maximization with and without time-of-flight (TOF). The shine-through artifact was defined as an erroneous accumulation of F-FDG between the bladder and the air region in the intestine without attenuation correction (AC) errors. The maximum standardized uptake value (SUV) of the artifact was measured, and the effect of TOF on this artifact was evaluated. The SUV in the bladder was compared in patients with and without the artifacts. A phantom containing two spheres simulating bladder and rectal gas was imaged while changing the radioactivity of F-FDG solution in the bladder sphere. The relationship between the bladder sphere radioactivity and the SUV of the shine-through artifacts was evaluated.
The shine-through artifact was more frequently observed on PET images reconstructed without TOF (12/106, 11.3%) as compared to PET images with TOF (8/106, 7.5%, p = 0.046). The SUV of the shine-through artifacts was significantly decreased by TOF reconstruction compared to non-TOF reconstruction (4.7 ± 1.7 vs 7.6 ± 3.1, p = 0.0078). The mean SUV of urinary bladders in patients with the artifacts was significantly higher than those without the artifacts on non-TOF images (74.9 ± 61.1 vs 46.3 ± 35.2, p = 0.038). In the phantom study, the SUV of the shine-through artifact increased as the radioactivity in the bladder-simulating sphere increased.
Shine-through artifacts were observed in approximately 10% of clinical F-FDG PET/CT examinations. Their magnitude is significantly associated with the radioactivity in the bladder and can be reduced by employing TOF. Recognizing this artifact allows for a more accurate interpretation of F-FDG pelvic studies.
在 F-FDG PET/CT 中，大热源附近区域会出现假的摄取增加，即“贯穿伪影”。这种伪影可能会对膀胱附近区域肿瘤累及程度的评估产生不利影响。本研究旨在评估临床 F-FDG PET/CT 检查中贯穿伪影的发生率，以及可能影响其发生和程度的因素。
使用 Discovery PET/CT 690 采集 PET/CT 图像。回顾性分析了 106 例因临床需要行 F-FDG PET/CT 检查的患者。使用三维有序子集期望最大化方法对 PET 图像进行重建，同时进行不带和带时间-of-flight（TOF）校正的重建。在没有衰减校正（AC）错误的情况下，将膀胱和肠内空气区域之间的 F-FDG 错误积聚定义为贯穿伪影。测量伪影的最大标准化摄取值（SUV），并评估 TOF 对该伪影的影响。比较有和无伪影患者的膀胱 SUV。在改变膀胱球体中 F-FDG 溶液放射性的同时，对包含两个球体的模拟膀胱和直肠气体的体模进行成像。评估膀胱球体放射性与贯穿伪影 SUV 之间的关系。
与带 TOF 重建的 PET 图像（8/106，7.5%）相比，不带 TOF 重建的 PET 图像（12/106，11.3%）更常观察到贯穿伪影（p=0.046）。与不带 TOF 重建相比，带 TOF 重建可显著降低贯穿伪影 SUV（4.7±1.7 比 7.6±3.1，p=0.0078）。无伪影患者的非 TOF 图像上的膀胱平均 SUV 显著低于有伪影患者（74.9±61.1 比 46.3±35.2，p=0.038）。在体模研究中，随着膀胱模拟球体中的放射性增加，贯穿伪影 SUV 增加。
在大约 10%的临床 F-FDG PET/CT 检查中观察到贯穿伪影。其大小与膀胱中的放射性显著相关，采用 TOF 可降低其大小。识别这种伪影可使 F-FDG 盆部研究的解释更加准确。
