Lowe Gerry, Spottiswoode Bruce, Declerck Jerome, Sullivan Keith, Sharif Mhd Saeed, Wong Wai-Lup, Sanghera Bal
Cancer Centre, Mount Vernon Hospital, London, UK.
Siemens Medical Solutions USA, Inc., Knoxville, TN, USA.
BJR Open. 2020 Jun 2;2(1):20190035. doi: 10.1259/bjro.20190035. eCollection 2020.
Harmonisation is the process whereby standardised uptake values from different scanners can be made comparable. This PET/CT pilot study aimed to evaluate the effectiveness of harmonisation of a modern scanner with image reconstruction incorporating resolution recovery (RR) with another vendor older scanner operated in two-dimensional (2D) mode, and for both against a European standard (EARL). The vendor-proprietary software EQ•PET was used, which achieves harmonisation with a Gaussian smoothing. A substudy investigated effect of RR on harmonisation.
Phantom studies on each scanner were performed to optimise the smoothing parameters required to achieve successful harmonisation. 80 patients were retrospectively selected; half were imaged on each scanner. As proof of principle, a cohort of 10 patients was selected from the modern scanner subjects to study the effects of RR on harmonisation.
Before harmonisation, the modern scanner without RR adhered to EARL specification. Using the phantom data, filters were derived for optimal harmonisation between scanners and with and without RR as applicable, to the EARL standard. The 80-patient cohort did not reveal any statistically significant differences. In the 10-patient cohort SUVmax for RR > no RR irrespective of harmonisation but differences lacked statistical significance (one-way ANOVA F(3.36) = 0.37, = 0.78). Bland-Altman analysis showed that harmonisation reduced the SUVmax ratio between RR and no RR to 1.07 (95% CI 0.96-1.18) with no outliers.
EQ•PET successfully enabled harmonisation between modern and older scanners and against the EARL standard. Harmonisation reduces SUVmax and dependence on the use of RR in the modern scanner.
EQ•PET is feasible to harmonise different PET/CT scanners and reduces the effect of RR on SUVmax.
归一化是使来自不同扫描仪的标准化摄取值具有可比性的过程。这项PET/CT试点研究旨在评估一台采用包含分辨率恢复（RR）的图像重建技术的现代扫描仪与另一台以二维（2D）模式运行的旧款不同厂商扫描仪之间归一化的有效性，并将两者与欧洲标准（EARL）进行对比。使用了厂商专有的EQ•PET软件，该软件通过高斯平滑实现归一化。一项子研究调查了RR对归一化的影响。
在每台扫描仪上进行体模研究，以优化实现成功归一化所需的平滑参数。回顾性选择了80名患者；其中一半在每台扫描仪上进行成像。作为原理验证，从现代扫描仪的受试者中挑选了10名患者组成队列，以研究RR对归一化的影响。
在进行归一化之前，未采用RR的现代扫描仪符合EARL规范。利用体模数据，得出了适用于有或无RR的扫描仪之间以及与EARL标准之间实现最佳归一化的滤波器。80名患者的队列未显示出任何统计学上的显著差异。在10名患者的队列中，无论是否进行归一化，RR组的SUVmax均大于无RR组，但差异无统计学意义（单因素方差分析F(3.36) = 0.37，P = 0.78）。Bland-Altman分析表明，归一化将RR组与无RR组之间的SUVmax比值降低至1.07（95%置信区间0.96 - 1.18），且无异常值。
EQ•PET成功实现了现代扫描仪与旧款扫描仪之间以及与EARL标准的归一化。归一化降低了现代扫描仪中的SUVmax以及对RR使用的依赖性。
EQ•PET在使不同PET/CT扫描仪归一化方面是可行的，并减少了RR对SUVmax的影响。
