School of Radiological Technology, Faculty of Health Science Technology, HRH Princess Chulabhorn College of Medical Sciences, Chulabhorn Royal Academy, Bangkok, Thailand.
National Cyclotron and PET Centre, Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok, Thailand.
J Appl Clin Med Phys. 2023 May;24(5):e13928. doi: 10.1002/acm2.13928. Epub 2023 Feb 10.
Intratumoral heterogeneity is associated with poor outcomes in head and neck cancer (HNC) patients owing to chemoradiotherapy resistance. [ F]-FDG positron emission tomography (PET) / Magnetic Resonance Imaging (MRI) provides spatial information about tumor mass, allowing intratumor heterogeneity assessment through histogram analysis. However, variability in quantitative PET/MRI parameter measurements could influence their reliability in assessing patient prognosis. Therefore, to use standardized uptake value (SUV) and apparent diffusion coefficient (ADC) parameters for assessing tumor response, this study aimed to measure SUV and ADC's variability and assess their relationship in HNC.
First, ADC variability was measured in an in-house diffusion phantom and in five healthy volunteers. The SUV variability was only measured with the NEMA phantom using a clinical imaging protocol. Furthermore, simultaneous PET/MRI data of 11 HNC patients were retrospectively collected from the National Cyclotron and PET center in Chulabhorn Hospital. Tumor contours were manually drawn from PET images by an experienced nuclear medicine radiologist before tumor volume segmentation. Next, SUV and ADC's histogram were used to extract statistic variables of ADC and SUV: mean, median, min, max, skewness, kurtosis, and 5 , 10 , 25 , 50 , 75 , 90 , and 95 percentiles. Finally, the correlation between the statistic variables of ADC and SUV, as well as Metabolic Tumor volume and Total Lesion Glycolysis parameters was assessed using Pearson's correlation.
This pilot study showed that both parameters' maximum coefficient of variation was 13.9% and 9.8% in the phantom and in vivo, respectively. Furthermore, we found a strong and negative correlation between SUV and ADV (r = -0.75, P = 0.01).
The SUV and ADC obtained by simultaneous PET/MRI can be potentially used as an imaging biomarker for assessing intratumoral heterogeneity in patients with HNC. The low variability and relationship between SUV and ADC could allow multimodal prediction of tumor response in future studies.
由于对头颈部癌症（HNC）患者的放化疗耐药性，肿瘤内异质性与不良预后相关。[ F]-FDG 正电子发射断层扫描（PET）/磁共振成像（MRI）提供了关于肿瘤质量的空间信息，允许通过直方图分析评估肿瘤内异质性。然而，定量 PET/MRI 参数测量的可变性可能会影响它们评估患者预后的可靠性。因此，为了使用标准化摄取值（SUV）和表观扩散系数（ADC）参数来评估肿瘤反应，本研究旨在测量 HNC 中 SUV 和 ADC 的可变性并评估它们之间的关系。
首先，在内部扩散体模和五名健康志愿者中测量 ADC 的可变性。仅使用临床成像协议在 NEMA 体模中测量 SUV 的可变性。此外，从 Chulabhorn 医院国家回旋加速器和 PET 中心回顾性收集了 11 名 HNC 患者的同时 PET/MRI 数据。肿瘤轮廓由一位经验丰富的核医学放射科医生从 PET 图像手动绘制，然后进行肿瘤体积分割。接下来，使用 SUV 和 ADC 的直方图从 PET 图像中提取 ADC 和 SUV 的统计变量：平均值、中位数、最小值、最大值、偏度、峰度以及 5%、10%、25%、50%、75%、90%和 95%的百分位数。最后，使用 Pearson 相关性评估 ADC 和 SUV 的统计变量以及代谢肿瘤体积和总病变糖酵解参数之间的相关性。
这项初步研究表明，这两个参数在体模和体内的最大变异系数分别为 13.9%和 9.8%。此外，我们发现 SUV 和 ADV 之间存在很强的负相关（r=-0.75，P=0.01）。
通过同时进行的 PET/MRI 获得的 SUV 和 ADC 可以作为评估 HNC 患者肿瘤内异质性的潜在成像生物标志物。SUV 和 ADC 之间的低可变性和相关性可能允许在未来的研究中对肿瘤反应进行多模态预测。
