表面扩散系数计算中的低b值高估了直肠癌中的扩散
Johanna A Hundvin1, Marius Bornstein2, Anne Negård3
1Cancer Clinic, Haukeland University Hospital, Bergen, Norway; Institute of Physics and Technology, University of Bergen, Bergen, Norway. johanna.austrheim.hundvin@helse-bergen.no.
Acta oncologica (Stockholm, Sweden)
|October 19, 2025
概括
在直肠癌中,为明显扩散系数 (ADC) 选择最佳的b值至关重要. 使用较高的b值 (≥100秒/mm2) 并排除低的b值 (≤100秒/mm2),可以减少ADC量化中的不确定性.
科学领域:
- 放射学 放射学是一门学科.
- 在瘤学瘤学.
- 医疗成像医学成像
背景情况:
- 在直肠癌中,明显扩散系数 (ADC) 的量化通常使用单指数模型.
- 在直肠癌中对ADC的最佳b值选择仍然未定义.
- 扩散权重MRI (DWI) 对于评估直肠癌特征至关重要.
研究的目的:
- 评估各种b值组合对直肠癌ADC值的影响.
- 用单指数模型确定最佳的b值选择,以准确量化直肠癌中的ADC.
- 为了比较来自不同b值组合的ADC值,与比特指数参考.
主要方法:
- 对23名直肠癌患者进行的前性观察性研究 (OxyTarget研究,NCT01816607).
- 在1.5T扫描仪上以7个b值 (0-1300秒/毫米2) 获得的扩散权重MRI (DWI).
- 两位放射科医生划出了感兴趣的全瘤体积;使用18个b值组合计算的ADC.
主要成果:
- 瘤ADC值根据b值组合有显著的变化.
- 排除低b值 (≤100s/mm2) 导致ADC值降低.
- 使用b值≥500s/mm2 (两个或三个值,包括1000s/mm2) 显示出与比位指数参考值的最小偏差,而包括b=0s/mm2导致过高估计.
结论:
- 使用单指数模型量化直肠癌ADC对b值选择非常敏感.
- 消除低b值 (≤100s/mm2) 通过最小化 perfusion 效应来减少计算不确定性.
- 建议使用b值>100s/mm2,包括高b值 (≥1000s/mm2),以可靠地评估直肠癌中的ADC.
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