Vogel Wouter V, Oyen Wim J G, Barentsz Jelle O, Kaanders Johannes H A M, Corstens Frans H M
Department of Nuclear Medicine, University Medical Center Nijmegen, Nijmegen, The Netherlands.
J Nucl Med. 2004 Jan;45 Suppl 1:15S-24S.
In the past decade, the integration of anatomic imaging and functional imaging has emerged as a new and promising diagnostic tool. Developments in software provided methods to integrate various modalities, such as PET, CT, MRI, and MR spectroscopy. The introduction of combined PET/CT scanners has boosted image fusion in this specific field and raised high expectations. Image fusion can be performed at 3 different levels: visual fusion, software fusion, and hardware fusion, each having strengths, weaknesses, and issues inherent to technique. Visual fusion is the traditional side-by-side reviewing of 2 separate modalities. Software image fusion provides evaluation of 2 modalities in 1 integrated image set. True hardware fusion of PET and CT does not exist at present. Currently, hardware fusion refers to a PET/CT scanner that consists of separate scanners, which positioned in line at a fixed distance, with projection of the PET image over the CT image. The suggested superiority of hardware fusion with these so-called hybrid PET/CT scanners over software fusion has sparked debate. Because scientific data that unequivocally show that state-of-the-art software fusion is less accurate than hardware fusion (as provided in hybrid PET/CT scanners) are unavailable, the primacy of a combined PET/CT scanner over stand-alone PET and CT is more a matter of belief than of science. Further research comparing the overall performance of PET/CT scanners with that of separate scanners with software for image fusion is much needed. The continuous development of better software for image fusion and respiratory and cardiac gating is also needed, not only for PET and CT imaging but also for fusion of PET with MRI and CT with MRI.
在过去十年中，解剖成像与功能成像的整合已成为一种新的且有前景的诊断工具。软件的发展提供了整合各种模态的方法，如正电子发射断层扫描（PET）、计算机断层扫描（CT）、磁共振成像（MRI）和磁共振波谱（MRS）。联合PET/CT扫描仪的引入推动了这一特定领域的图像融合，并引发了人们的高度期望。图像融合可在三个不同层面进行：视觉融合、软件融合和硬件融合，每个层面都有其自身的优势、劣势以及技术固有的问题。视觉融合是对两种单独模态进行传统的并列查看。软件图像融合可在一个整合图像集中对两种模态进行评估。目前并不存在PET与CT真正的硬件融合。当前，硬件融合指的是一种由分开的扫描仪组成的PET/CT扫描仪，这些扫描仪以固定距离排成一排，PET图像投影在CT图像之上。这些所谓的混合型PET/CT扫描仪的硬件融合相对于软件融合所宣称的优势引发了争论。由于尚无明确表明最先进的软件融合不如硬件融合（如混合型PET/CT扫描仪所提供的）准确的科学数据，PET/CT联合扫描仪相对于单独的PET和CT的首要地位更多是一种信念问题而非科学问题。非常需要进一步开展研究，比较PET/CT扫描仪与带有图像融合软件的单独扫描仪的整体性能。还需要持续开发更好的图像融合软件以及呼吸和心脏门控软件，这不仅适用于PET和CT成像，也适用于PET与MRI以及CT与MRI的融合。
