Department of Nuclear Medicine, RWTH University Hospital, Aachen, Germany.
Institute of Neuroscience and Medicine (INM-3, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich, Germany.
Mol Imaging Biol. 2024 Feb;26(1):36-44. doi: 10.1007/s11307-023-01861-2. Epub 2023 Oct 17.
Morphological imaging using MRI is essential for brain tumour diagnostics. Dynamic susceptibility contrast (DSC) perfusion-weighted MRI (PWI), as well as amino acid PET, may provide additional information in ambiguous cases. Since PWI is often unavailable in patients referred for amino acid PET, we explored whether maps of relative cerebral blood volume (rCBV) in brain tumours can be extracted from the early phase of PET using O-(2-F-fluoroethyl)-L-tyrosine (F-FET).
Using a hybrid brain PET/MRI scanner, PWI and dynamic F-FET PET were performed in 33 patients with cerebral glioma and four patients with highly vascularized meningioma. The time interval from 0 to 2 min p.i. was selected to best reflect the blood pool phase in F-FET PET. For each patient, maps of MR-rCBV, early F-FET PET (0-2 min p.i.) and late F-FET PET (20-40 min p.i.) were generated and coregistered. Volumes of interest were placed on the tumour (VOI-TU) and normal-appearing brain (VOI-REF). The correlation between tumour-to-brain ratios (TBR) of the different parameters was analysed. In addition, three independent observers evaluated MR-rCBV and early F-FET maps (F-FET-rCBV) for concordance in signal intensity, tumour extent and intratumoural distribution.
TBRs calculated from MR-rCBV and F-FET-rCBV showed a significant correlation (r = 0.89, p < 0.001), while there was no correlation between late F-FET PET and MR-rCBV (r = 0.24, p = 0.16) and F-FET-rCBV (r = 0.27, p = 0.11). Visual rating yielded widely agreeing findings or only minor differences between MR-rCBV maps and F-FET-rCBV maps in 93 % of the tumours (range of three independent raters 91-94%, kappa among raters 0.78-1.0).
Early F-FET maps (0-2 min p.i.) in gliomas provide similar information to MR-rCBV maps and may be helpful when PWI is not possible or available. Further studies in gliomas are needed to evaluate whether F-FET-rCBV provides the same clinical information as MR-rCBV.
磁共振成像（MRI）的形态学成像对于脑肿瘤的诊断至关重要。动态对比磁共振灌注加权成像（PWI）以及氨基酸 PET 可能在模棱两可的情况下提供额外的信息。由于在转介进行氨基酸 PET 的患者中 PWI 通常不可用，因此我们探讨了是否可以从 O-(2-F-氟乙基)-L-酪氨酸（F-FET）的 PET 早期阶段提取脑肿瘤的相对脑血容量（rCBV）图。
使用混合脑 PET/MRI 扫描仪，对 33 例脑胶质瘤患者和 4 例高血管脑膜瘤患者进行 PWI 和动态 F-FET PET 检查。选择从 0 到 2 分钟后注射（p.i.）的时间间隔，以最佳反映 F-FET PET 中的血池期。对于每个患者，生成并配准 MR-rCBV、早期 F-FET PET（0-2 分钟 p.i.）和晚期 F-FET PET（20-40 分钟 p.i.）图。在肿瘤（VOI-TU）和正常脑（VOI-REF）上放置感兴趣区（VOI）。分析不同参数的肿瘤与脑比值（TBR）之间的相关性。此外，三位独立观察者评估了 MR-rCBV 和早期 F-FET 图（F-FET-rCBV）在信号强度、肿瘤范围和肿瘤内分布方面的一致性。
MR-rCBV 和 F-FET-rCBV 计算的 TBR 呈显著相关（r = 0.89，p < 0.001），而晚期 F-FET PET 与 MR-rCBV（r = 0.24，p = 0.16）和 F-FET-rCBV（r = 0.27，p = 0.11）无相关性。在 93%的肿瘤中，MR-rCBV 图和 F-FET-rCBV 图之间的视觉评分产生了广泛一致的发现或仅存在较小差异（三位独立评分者的范围为 91-94%，评分者之间的kappa 值为 0.78-1.0）。
在胶质瘤中，早期 F-FET 图（0-2 分钟 p.i.）提供了与 MR-rCBV 图相似的信息，在无法或无法进行 PWI 时可能会有所帮助。需要在胶质瘤中进一步研究，以评估 F-FET-rCBV 是否提供与 MR-rCBV 相同的临床信息。
