Štokelj Eva, Simončič Urban
Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia.
Jozef Stefan Institute, 1000 Ljubljana, Slovenia.
Sensors (Basel). 2025 Jul 7;25(13):4230. doi: 10.3390/s25134230.
Quantitative FDG-PET brain imaging across multiple centers is challenged by inter-scanner variability, impacting the comparability of neuroimaging data. This study proposes a data-driven image-based harmonization protocol to address these discrepancies without relying on traditional phantom scans. The protocol uses spatially normalized FDG-PET brain images to estimate scanner-specific Gaussian smoothing filters, optimizing parameters via the structural similarity index (SSIM). Validation was performed using images from cognitively normal individuals and Alzheimer's disease patients from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Results demonstrated robust harmonization at moderate target resolutions (8 and 10 mm FWHM), with filter estimates consistently within 1.2 mm of phantom-derived ground truths. However, at higher resolutions (6 mm FWHM), discrepancies reached up to 3 mm, reflecting reduced accuracy. These deviations were particularly evident for high-resolution scanners like HRRT, likely due to elevated noise levels and smaller sample sizes. The presented harmonization method effectively reduces inter-scanner variability in retrospective FDG-PET studies, especially valuable when phantom scans are unavailable. Nonetheless, the current limitations at finer resolutions underline the necessity for methodological refinements to meet the demands of evolving high-resolution PET imaging technologies.
跨多个中心的定量FDG-PET脑成像受到扫描仪间变异性的挑战，这影响了神经影像数据的可比性。本研究提出了一种基于数据驱动的图像协调方案，以解决这些差异，而无需依赖传统的体模扫描。该方案使用空间归一化的FDG-PET脑图像来估计特定于扫描仪的高斯平滑滤波器，并通过结构相似性指数（SSIM）优化参数。使用来自阿尔茨海默病神经影像倡议（ADNI）数据库的认知正常个体和阿尔茨海默病患者的图像进行了验证。结果表明，在中等目标分辨率（8和10毫米半高宽）下实现了稳健的协调，滤波器估计值始终在体模衍生的地面真值的1.2毫米范围内。然而，在更高分辨率（6毫米半高宽）下，差异达到3毫米，反映出准确性降低。这些偏差在像HRRT这样的高分辨率扫描仪中尤为明显，可能是由于噪声水平升高和样本量较小。所提出的协调方法有效地减少了回顾性FDG-PET研究中的扫描仪间变异性，当体模扫描不可用时尤其有价值。尽管如此，当前在更高分辨率下的局限性凸显了方法改进的必要性，以满足不断发展的高分辨率PET成像技术的需求。
