Zeimpekis Konstantinos G, Barbosa Felipe, Hüllner Martin, ter Voert Edwin, Davison Helen, Veit-Haibach Patrick, Delso Gaspar
Department of Nuclear Medicine, University Hospital Zurich, Rämistrasse 100, CH-8091, Zürich, Switzerland.
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland.
Mol Imaging Biol. 2015 Oct;17(5):735-44. doi: 10.1007/s11307-015-0845-5.
The purpose of this study was to compare only the performance of the PET component between a TOF-PET/CT (henceforth noted as PET/CT) scanner and an integrated TOF-PET/MRI (henceforth noted as PET/MRI) scanner concerning image quality parameters and quantification in terms of standardized uptake value (SUV) as a function of acquisition time (a surrogate of dose). The CT and MR image quality were not assessed, and that is beyond the scope of this study.
Five brain and five whole-body patients were included in the study. The PET/CT scan was used as a reference and the PET/MRI acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of the emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts, and noise were evaluated. SUV measurements were taken in the liver and in the white matter to compare quantification.
Quantitative evaluation showed strong correlation between PET/CT and PET/MRI brain SUVs. Liver correlation was good, however, with lower uptake estimation in PET/MRI, partially justified by bio-redistribution. The clinical evaluation showed that PET/MRI offers higher image quality and sharpness with lower levels of noise and artifacts compared to PET/CT with reduced acquisition times for whole-body scans while for brain scans there is no significant difference.
The TOF-PET/MRI showed higher image quality compared to TOF-PET/CT as tested with reduced imaging times. However, this result accounts mainly for body imaging, while no significant differences were found in brain imaging.
本研究的目的是仅比较时间飞跃正电子发射断层扫描/计算机断层扫描（以下简称PET/CT）扫描仪和集成时间飞跃正电子发射断层扫描/磁共振成像（以下简称PET/MRI）扫描仪在图像质量参数以及标准化摄取值（SUV）作为采集时间（剂量的替代指标）函数的定量方面PET组件的性能。未评估CT和MR图像质量，这超出了本研究的范围。
本研究纳入了5例脑部患者和5例全身患者。以PET/CT扫描作为参考，并根据扫描之间的衰减连续调整PET/MRI的采集时间，以使两个系统接收到相同量的发射信号。然后对采集时间进行回顾性缩短，以评估PET/MRI在较低计数率下的性能。评估了图像质量、图像清晰度、伪影和噪声。在肝脏和白质中进行SUV测量以比较定量结果。
定量评估显示PET/CT和PET/MRI脑部SUV之间有很强的相关性。肝脏的相关性良好，然而，PET/MRI中的摄取估计较低，生物再分布部分解释了这一点。临床评估表明，与PET/CT相比，PET/MRI具有更高的图像质量和清晰度，噪声和伪影水平更低，全身扫描的采集时间缩短，而脑部扫描则无显著差异。
经测试，在成像时间缩短的情况下，时间飞跃PET/MRI比时间飞跃PET/CT显示出更高的图像质量。然而，这一结果主要适用于身体成像，在脑部成像中未发现显著差异。
