Wallstén Elin, Axelsson Jan, Jonsson Joakim, Karlsson Camilla Thellenberg, Nyholm Tufve, Larsson Anne
Department of Radiation Sciences, Radiation Physics, Umeå University, 901 85, Umeå, Sweden.
Department of Radiation Sciences, Oncology, Umeå University, 901 85, Umeå, Sweden.
EJNMMI Phys. 2020 Nov 23;7(1):68. doi: 10.1186/s40658-020-00336-5.
Attenuation correction of PET/MRI is a remaining problem for whole-body PET/MRI. The statistical decomposition algorithm (SDA) is a probabilistic atlas-based method that calculates synthetic CTs from T2-weighted MRI scans. In this study, we evaluated the application of SDA for attenuation correction of PET images in the pelvic region.
Twelve patients were retrospectively selected from an ongoing prostate cancer research study. The patients had same-day scans of [11C]acetate PET/MRI and CT. The CT images were non-rigidly registered to the PET/MRI geometry, and PET images were reconstructed with attenuation correction employing CT, SDA-generated CT, and the built-in Dixon sequence-based method of the scanner. The PET images reconstructed using CT-based attenuation correction were used as ground truth.
The mean whole-image PET uptake error was reduced from - 5.4% for Dixon-PET to - 0.9% for SDA-PET. The prostate standardized uptake value (SUV) quantification error was significantly reduced from - 5.6% for Dixon-PET to - 2.3% for SDA-PET.
Attenuation correction with SDA improves quantification of PET/MR images in the pelvic region compared to the Dixon-based method.
PET/MRI的衰减校正是全身PET/MRI的一个遗留问题。统计分解算法（SDA）是一种基于概率图谱的方法，可从T2加权MRI扫描中计算合成CT。在本研究中，我们评估了SDA在盆腔区域PET图像衰减校正中的应用。
从一项正在进行的前列腺癌研究中回顾性选取12例患者。这些患者在同一天进行了[11C]醋酸盐PET/MRI和CT扫描。将CT图像非刚性配准到PET/MRI的几何结构上，并使用CT、SDA生成的CT以及扫描仪基于内置狄克逊序列的方法进行衰减校正来重建PET图像。使用基于CT的衰减校正重建的PET图像作为参考标准。
整个图像的PET摄取平均误差从狄克逊PET的-5.4%降低到SDA-PET的-0.9%。前列腺标准化摄取值（SUV）定量误差从狄克逊PET的-5.6%显著降低到SDA-PET的-2.3%。
与基于狄克逊的方法相比，使用SDA进行衰减校正可改善盆腔区域PET/MR图像的定量分析。
