Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
J Nucl Med. 2018 May;59(5):846-851. doi: 10.2967/jnumed.117.197665. Epub 2017 Nov 2.
The current study tested a newly developed flexible PET (fxPET) scanner prototype. This fxPET system involves dual arc-shaped detectors based on silicon photomultipliers that are designed to fit existing MRI devices, allowing us to obtain fused PET and MR images by sequential PET and MR scanning. This prospective study sought to evaluate the image quality, lesion detection rate, and quantitative values of fxPET in comparison with conventional whole-body (WB) PET and to assess the accuracy of registration. Seventeen patients with suspected or known malignant tumors were analyzed. Approximately 1 h after intravenous injection of F-FDG, WB PET/CT was performed, followed by fxPET and MRI. For reconstruction of fxPET images, MRI-based attenuation correction was applied. The quality of fxPET images was visually assessed, and the number of detected lesions was compared between the 2 imaging methods. SUV and maximum average SUV within a 1 cm spheric volume (SUV) of lesions were also compared. In addition, the magnitude of misregistration between fxPET and MR images was evaluated. The image quality of fxPET was acceptable for diagnosis of malignant tumors. There was no significant difference in detectability of malignant lesions between fxPET and WB PET ( > 0.05). However, the fxPET system did not exhibit superior performance to the WB PET system. There were strong positive correlations between the 2 imaging modalities in SUV (ρ = 0.88) and SUV (ρ = 0.81). SUV and SUV measured with fxPET were approximately 1.1-fold greater than measured with WB PET. The average misregistration between fxPET and MR images was 5.5 ± 3.4 mm. Our preliminary data indicate that running an fxPET scanner near an existing MRI system provides visually and quantitatively acceptable fused PET/MR images for diagnosis of malignant lesions.
本研究测试了一种新开发的灵活正电子发射断层扫描（PET）扫描仪原型。该 fxPET 系统基于硅光电倍增器的双弧形探测器，旨在适配现有的磁共振成像（MRI）设备，使我们能够通过顺序 PET 和 MRI 扫描获得融合的 PET 和 MR 图像。这项前瞻性研究旨在评估 fxPET 的图像质量、病灶检出率和定量值，与传统的全身（WB）PET 进行比较，并评估配准的准确性。分析了 17 例疑似或已知恶性肿瘤的患者。静脉注射 F-FDG 后约 1 小时，进行 WB PET/CT 检查，然后进行 fxPET 和 MRI。对于 fxPET 图像的重建，应用了基于 MRI 的衰减校正。对 fxPET 图像的质量进行了视觉评估，并比较了两种成像方法检测到的病灶数量。还比较了病灶 1cm 球形容积内的标准摄取值（SUV）和最大平均 SUV（SUV）。此外，评估了 fxPET 和 MR 图像之间的配准误差幅度。fxPET 的图像质量可接受，可用于诊断恶性肿瘤。fxPET 和 WB PET 对恶性病灶的检出率无显著差异（>0.05）。然而，fxPET 系统的性能并不优于 WB PET 系统。两种成像方式在 SUV（ρ=0.88）和 SUV（ρ=0.81）方面存在很强的正相关性。fxPET 测量的 SUV 和 SUV 约比 WB PET 测量的大 1.1 倍。fxPET 和 MR 图像之间的平均配准误差为 5.5±3.4mm。我们的初步数据表明，在现有的 MRI 系统附近运行 fxPET 扫描仪可提供用于诊断恶性病变的视觉和定量可接受的融合 PET/MR 图像。
