Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany.
Eur J Radiol. 2012 Nov;81(11):3472-8. doi: 10.1016/j.ejrad.2011.12.027. Epub 2012 Jan 18.
The present work illustrates the current state of image quality and diagnostic accuracy in a new hybrid BrainPET/MR.
50 patients with intracranial masses, head and upper neck tumors or neurodegenerative diseases were examined with a hybrid BrainPET/MR consisting of a conventional 3T MR system and an MR-compatible PET insert. Directly before PET/MR, all patients underwent a PET/CT examination with either [18F]-FDG, [11C]-methionine or [68Ga]-DOTATOC. In addition to anatomical MR scans, functional sequences were performed including diffusion tensor imaging (DTI), arterial spin labeling (ASL) and proton-spectroscopy. Image quality score of MR imaging was evaluated using a 4-point-scale. PET data quality was assessed by evaluating FDG-uptake and tumor delineation with [11C]-methionine and [68Ga]-DOTATOC. FDG uptake quantification accuracy was evaluated by means of ROI analysis (right and left frontal and temporo-occipital lobes). The asymmetry indices and ratios between frontal and occipital ROIs were compared.
In 45/50 patients, PET/MR examination was successful. Visual analysis revealed a diagnostic image quality of anatomical MR imaging (mean quality score T2 FSE: 1.27±0.54; FLAIR: 1.38±0.61). ASL and proton-spectroscopy was possible in all cases. In DTI, dental artifacts lead to one non-diagnostic dataset (mean quality score DTI: 1.32±0.69; ASL: 1.10±0.31). PET datasets of PET/MR and PET/CT offered comparable tumor delineation with [11C]-methionine; additional lesions were found in 2/8 [(68)Ga]-DOTATOC-PET in the PET/MR. Mean asymmetry index revealed a high accordance between PET/MR and PET/CT (1.5±2.2% vs. 0.9±3.6%; mean ratio (frontal/parieto-occipital) 0.93±0.08 vs. 0.96±0.05), respectively.
The hybrid BrainPET/MR allows for molecular, anatomical and functional imaging with uncompromised MR image quality and a high accordance of PET results between PET/MR and PET/CT. These results justify the application of this technique in further clinical studies and may contribute to the transfer into whole-body PET/MR systems.
本研究展示了新型脑 PET/MR 中的图像质量和诊断准确性的现状。
50 例颅内肿块、头颈部肿瘤或神经退行性疾病患者接受了由常规 3T MR 系统和 MR 兼容的 PET 插入件组成的杂交 BrainPET/MR 检查。在 PET/MR 检查之前，所有患者均进行了[18F]-FDG、[11C]-蛋氨酸或[68Ga]-DOTATOC 的 PET/CT 检查。除了进行解剖学 MR 扫描外，还进行了功能序列检查，包括弥散张量成像（DTI）、动脉自旋标记（ASL）和质子波谱。使用 4 分制评估 MR 成像的图像质量评分。通过评估[11C]-蛋氨酸和[68Ga]-DOTATOC 的 FDG 摄取和肿瘤描绘来评估 PET 数据质量。通过 ROI 分析（右和左额和颞枕叶）评估 FDG 摄取定量准确性。比较了额 ROI 和枕 ROI 之间的不对称指数和比率。
在 50 例患者中，有 45 例成功进行了 PET/MR 检查。视觉分析显示解剖学 MR 成像（T2 FSE 的平均质量评分：1.27±0.54；FLAIR：1.38±0.61）的诊断图像质量。所有情况下均可行 ASL 和质子波谱。在 DTI 中，牙垢导致 1 个不可诊断的数据集（DTI 的平均质量评分：1.32±0.69；ASL：1.10±0.31）。PET/MR 和 PET/CT 的 PET 数据集提供了具有可比性的[11C]-蛋氨酸肿瘤描绘；在 2/8 例患者中，在 PET/MR 中发现了额外的病变（68）Ga]-DOTATOC-PET。平均不对称指数显示了 PET/MR 和 PET/CT 之间的高度一致性（1.5±2.2%比 0.9±3.6%；平均比率（额/顶枕叶）0.93±0.08 比 0.96±0.05）。
杂交 BrainPET/MR 允许进行分子、解剖和功能成像，同时保持 MR 图像质量不受影响，并且 PET 结果在 PET/MR 和 PET/CT 之间具有高度一致性。这些结果证明了该技术在进一步临床研究中的应用，并可能有助于将其应用于全身 PET/MR 系统。
