Purpose

To assess the influence of long-axial field-of-view (LAFOV) PET/CT systems on radiomics feature reliability, to assess the suitability for short-duration or low-activity acquisitions for textural feature analysis and to investigate the influence of acceptance angle.

Methods

34 patients were analysed: twelve patients underwent oncological 2-[18F]-FDG PET/CT, fourteen [18F]PSMA-1007 and eight [68Ga]Ga-DOTATOC. Data were obtained using a 106 cm LAFOV system for 10 min. Sinograms were generated from list-mode data corresponding to scan durations of 2, 5, 10, 20, 30, 60, 120, 240, 360 and 600s using both standard (minimum ring difference MRD 85 crystals) and maximum acceptance angles (MRD 322). Target lesions were segmented and radiomics features were calculated. To assess feature correlation, Pearson’s product-moment correlation coefficient (PPMCC) was calculated with respect to the full duration acquisition for MRD 85 and 322 respectively. The number of features with excellent (r > 0.9), moderate (r > 0.7 and < 0.9) and poor (r ≤ 0.7) correlation was compared as a measure of feature stability. Intra-class heterogeneity was assessed by means of the quartile coefficient of dispersion.

Results

As expected, PPMCC improved with acquisition time for all features. By 240s almost all features showed at least moderate agreement with the full count (C100%) data, and by 360s almost all showed excellent agreement. Compared to standard-axial field of view (SAFOV) equivalent scans, fewer features showed moderate or poor agreement, and this was most pronounced for [68Ga]Ga-DOTATOC. Data obtained at C100% at MRD 322 were better able to capture between-patient heterogeneities.

Conclusion

The improved feature reliability at longer acquisition times and higher MRD demonstrate the advantages of high sensitivity LAFOV systems for reproducible and low-noise data. High fidelity between MRD 85 and MRD 322 was seen at all scan durations > 2s. When contrasted with data comparable to a simulated SAFOV acquisition, full-count and full-MRD data were better able to capture underlying feature heterogeneities.

中文翻译：

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长轴视场 PET/CT 提高了放射组学特征的可靠性

 目的

评估长轴视场 （LAFOV） PET/CT 系统对影像组学特征可靠性的影响，评估短时或低活性采集对纹理特征分析的适用性，并研究接受角的影响。

 方法

分析了 34 例患者： 12 例患者接受了肿瘤 2-[18F]-FDG PET/CT，14 例 [18F]-PSMA-1007 和 8 例 [68Ga]Ga-DOTATOC。使用 106 cm LAFOV 系统获得 10 分钟的数据。Sinogram 由对应于 2、5、10、20、30、60、120、240、360 和 600 秒扫描持续时间的列表模式数据生成，使用标准 （最小环差 MRD 85 晶体） 和最大接受角 （MRD 322）。对目标病灶进行分割并计算放射组学特征。为了评估特征相关性，分别计算了 MRD 85 和 322 的整个持续时间采集的 Pearson 乘积矩相关系数 （PPMCC）。比较了具有极好 （r > 0.9）、中等 （r > 0.7 和 < 0.9） 和差 （r ≤ 0.7） 相关性的特征数量，作为特征稳定性的衡量标准。通过四分位数离散系数评估类内异质性。

 结果

正如预期的那样，PPMCC 随着所有特征的采集时间而改进。到 240 年代，几乎所有特征都显示出与完整计数 （C100%） 数据的至少中等一致性，到 360 年代，几乎所有特征都显示出极好的一致性。与标准轴向视野 （SAFOV） 等效扫描相比，显示中等或差一致性的特征较少，这在 [68Ga]Ga-DOTATOC 中最为明显。在 MRD 322 中以 C100% 获得的数据能够更好地捕捉患者之间的异质性。

 结论

在更长的采集时间和更高的 MRD 下改进的特征可靠性证明了高灵敏度 LAFOV 系统在获得可重现和低噪声数据方面的优势。在所有扫描持续时间 > 2s 中都可以看到 MRD 85 和 MRD 322 之间的高保真度。与模拟 SAFOV 采集相当的数据相比，全计数和全 MRD 数据能够更好地捕捉潜在的特征异质性。