Department of Medical Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands.
Eur J Nucl Med Mol Imaging. 2012 Dec;39(12):1858-67. doi: 10.1007/s00259-012-2233-6. Epub 2012 Sep 4.
Several studies showed potential for monitoring response to systemic therapy in metastatic colorectal cancer patients with (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Before (18)F-FDG PET can be implemented for response evaluation the repeatability should be known. This study was performed to assess the magnitude of the changes in standardized uptake value (SUV), volume and total lesion glycolysis (TLG) in colorectal liver metastases and validate the biological basis of (18)F-FDG PET in colorectal liver metastases.
Twenty patients scheduled for liver metastasectomy underwent two (18)F-FDG PET scans within 1 week. Bland-Altman analysis was performed to assess repeatability of SUV(max), SUV(mean), volume and TLG. Tumours were delineated using an adaptive threshold method (PET(SBR)) and a semiautomatic fuzzy locally adaptive Bayesian (FLAB) delineation method.
Coefficient of repeatability of SUV(max) and SUV(mean) were ∼39 and ∼31 %, respectively, independent of the delineation method used and image reconstruction parameters. However, repeatability was worse in recently treated patients. The FLAB delineation method improved the repeatability of the volume and TLG measurements compared to PET(SBR), from coefficients of repeatability of over 85 % to 45 % and 57 % for volume and TLG, respectively. Glucose transporter 1 (GLUT1) expression correlated to the SUV(mean). Vascularity (CD34 expression) and tumour hypoxia (carbonic anhydrase IX expression) did not correlate with (18)F-FDG PET parameters.
In conclusion, repeatability of SUV(mean) and SUV(max) was mainly affected by preceding systemic therapy. The repeatability of tumour volume and TLG could be improved using more advanced and robust delineation approaches such as FLAB, which is recommended when (18)F-FDG PET is utilized for volume or TLG measurements. Improvement of repeatability of PET measurements, for instance by dynamic PET scanning protocols, is probably necessary to effectively use PET for early response monitoring.
几项研究表明，在转移性结直肠癌患者中，使用（18）F-氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）对全身治疗的反应具有潜在监测作用。在（18）F-FDG PET 可用于反应评估之前，应了解其重复性。本研究旨在评估结直肠肝转移中标准化摄取值（SUV）、体积和总病灶糖酵解（TLG）的变化幅度，并验证（18）F-FDG PET 在结直肠肝转移中的生物学基础。
20 例计划行肝转移切除术的患者在 1 周内接受了两次（18）F-FDG PET 扫描。采用 Bland-Altman 分析评估 SUV(max)、SUV(mean)、体积和 TLG 的重复性。使用自适应阈值法（PET(SBR)）和半自动模糊局部自适应贝叶斯（FLAB）勾画方法对肿瘤进行勾画。
SUV(max)和 SUV(mean)的重复性系数分别约为 39%和 31%，与使用的勾画方法和图像重建参数无关。然而，在最近接受治疗的患者中，重复性较差。与 PET(SBR)相比，FLAB 勾画方法提高了体积和 TLG 测量的重复性，体积和 TLG 的重复性系数分别从 85%以上降至 45%和 57%。葡萄糖转运蛋白 1（GLUT1）的表达与 SUV(mean)相关。血管生成（CD34 表达）和肿瘤缺氧（碳酸酐酶 IX 表达）与（18）F-FDG PET 参数不相关。
总之，SUV(mean)和 SUV(max)的重复性主要受先前全身治疗的影响。使用更先进和稳健的勾画方法（如 FLAB）可提高肿瘤体积和 TLG 的重复性，在使用（18）F-FDG PET 进行体积或 TLG 测量时推荐使用该方法。提高 PET 测量的重复性，例如通过动态 PET 扫描方案，可能对于有效使用 PET 进行早期反应监测是必要的。
