Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, 6-10 Senshu-Kubota Machi, Akita, 010-0874, Japan.
Department of Management Science and Engineering, Faculty of System Science and Technology, Akita Prefectural University, Yurihonjo, Japan.
Ann Nucl Med. 2022 Aug;36(8):717-727. doi: 10.1007/s12149-022-01753-5. Epub 2022 May 26.
In quantitative positron emission tomography (PET) of the brain, partial volume effect due mainly to the finite spatial resolution of the PET scanner (> 3 mm full width at half maximum [FWHM]) is a primary source of error in the measurement of tracer uptake, especially in small structures such as the cerebral cortex (typically < 3 mm thickness). The aim of this study was to evaluate the partial volume correction (PVC) performance of point spread function-incorporated reconstruction (PSF reconstruction) in combination with the latest digital PET scanner. This evaluation was performed through direct comparisons with magnetic resonance imaging (MR)-based PVC (used as a reference method) in a human brain study.
Ten healthy subjects underwent brain F-FDG PET (30-min acquisition) on a digital PET/CT system (Siemens Biograph Vision, 3.5-mm FWHM scanner resolution at the center of the field of view) and anatomical T1-weighted MR imaging for MR-based PVC. PSF reconstruction was applied with a wide range of iterations (4 to 256; 5 subsets). FDG uptake in the cerebral cortex was evaluated using the standardized uptake value ratio (SUVR) and compared between PSF reconstruction and MR-based PVC.
Cortical structures were visualized by PSF reconstruction with several tens of iterations and were anatomically well matched with the MR-derived cortical segments. Higher numbers of iterations resulted in higher cortical SUVRs, which approached those of MR-based PVC (1.76), although even with the maximum number of iterations they were still smaller by 16% (1.47), corresponding to approximately 1.5-mm FWHM of the effective spatial resolution.
With the latest digital PET scanner, PSF reconstruction can be used as a PVC technique in brain PET, albeit with suboptimal resolution recovery. A relative advantage of PSF reconstruction is that it can be applied not only to cerebral cortical regions, but also to various small structures such as small brain nuclei that are hardly visualized on anatomical T1-weighted imaging, and thus hardly recovered by MR-based PVC.
在脑定量正电子发射断层扫描（PET）中，主要由于 PET 扫描仪的有限空间分辨率（> 3mm 半峰全宽[FWHM]）引起的部分容积效应是测量示踪剂摄取的主要误差源，尤其是在小结构中，如大脑皮层（通常<3mm 厚）。本研究旨在评估点扩散函数重建（PSF 重建）与最新数字 PET 扫描仪相结合的部分容积校正（PVC）性能。通过在人体脑部研究中与基于磁共振成像（MRI）的 PVC（用作参考方法）进行直接比较来进行此评估。
10 名健康受试者在数字 PET/CT 系统（西门子 Biograph Vision，视野中心的 3.5mm FWHM 扫描仪分辨率）上进行脑 F-FDG PET（30 分钟采集），并进行基于 MRI 的 PVC 的解剖 T1 加权 MR 成像。应用了广泛的迭代次数（4 到 256；5 个子集）进行 PSF 重建。使用标准化摄取值比（SUVr）评估大脑皮层的 FDG 摄取，并将 PSF 重建与基于 MRI 的 PVC 进行比较。
PSF 重建可以使用数十次迭代来可视化皮层结构，并且与基于 MRI 的皮层段在解剖学上非常匹配。较高的迭代次数导致较高的皮层 SUVr，接近基于 MRI 的 PVC（1.76），尽管即使使用最大迭代次数，它们仍然小 16%（1.47），对应于约 1.5mm FWHM 的有效空间分辨率。
使用最新的数字 PET 扫描仪，PSF 重建可作为脑 PET 的 PVC 技术，但分辨率恢复不理想。PSF 重建的一个相对优势是，它不仅可以应用于大脑皮层区域，还可以应用于各种小结构，如在解剖 T1 加权成像上难以可视化的小脑核，因此难以通过基于 MRI 的 PVC 恢复。
