Schmidt Gerwin P, Kramer Harald, Reiser Maximilian F, Glaser Christian
Department of Clinical Radiology, University Hospitals Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany.
Top Magn Reson Imaging. 2007 Jun;18(3):193-202. doi: 10.1097/RMR.0b013e318093e6bo.
The advent of positron emission tomography-computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) has introduced tumor imaging with a systemic and functional approach compared with established sequential, multimodal diagnostic algorithms.Whole-body PET with [18F]-fluoro-2-desoxy-glucose is a useful imaging procedure for tumor staging and monitoring that can visualize active tumor tissue by detecting pathological glucose metabolism. The combination of PET with the detailed anatomical information of multislice computed tomography as dual-modality scanners has markedly increased lesion localization and diagnostic accuracy compared with both modalities as standalone applications.Hardware innovations, such as the introduction of multi-receiver channel whole-body MRI scanners at 1.5 and, recently, 3 T, combined with acquisition acceleration techniques, have made high-resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution, and contrast media dynamics can be combined with whole-body anatomical coverage in a multiplanar imaging approach. More flexible protocols (eg, T1-weighted turbo spin-echo and short inversion recovery imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen) can be performed within 45 minutes.Whole-body magnetic resonance imaging has recently been proposed for tumor screening of asymptomatic individuals, and potentially life-changing diagnoses, such as formerly unknown malignancy, have been reported. However, larger patient cohort studies will have to show the cost efficiency and the clinical effectiveness of such an approach.For initial tumor staging, PET-CT has proved more accurate for the definition of T-stage and lymph node assessment, mainly because of the missing metabolic information in WB-MRI. However, new applications, such as magnetic resonance whole-body diffusion-weighted imaging or lymphotropic contrast agents, may significantly increase sensitivity in near future. Whole-body magnetic resonance imaging has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and as a whole-body bone marrow screening application. Within this context, WB-MRI is highly accurate for the detection of skeletal metastases and staging of multiple myeloma. This article summarizes recent developments of CT/PET-CT and WB-MRI and highlights their performance within the scope of systemic oncological imaging.
与已确立的序贯多模态诊断算法相比，正电子发射断层扫描-计算机断层扫描（PET-CT）和全身磁共振成像（WB-MRI）的出现引入了一种系统性和功能性的肿瘤成像方法。采用[18F]-氟-2-脱氧葡萄糖的全身PET是一种用于肿瘤分期和监测的有用成像程序，它可以通过检测病理性葡萄糖代谢来可视化活跃的肿瘤组织。PET与多层计算机断层扫描的详细解剖信息相结合作为双模态扫描仪，与两种模式单独应用相比，显著提高了病变定位和诊断准确性。硬件创新，如1.5 T以及最近3 T的多接收通道全身MRI扫描仪的引入，结合采集加速技术，使得高分辨率WB-MRI在临床上可行。现在，通过多平面成像方法，可以将对具有各种软组织对比度、空间分辨率和造影剂动力学的各个器官的专门评估与全身解剖覆盖相结合。更灵活的方案（例如，T1加权快速自旋回波和短反转恢复成像、专门的肺部成像或腹部动态对比增强研究）可以在45分钟内完成。全身磁共振成像最近被提议用于无症状个体的肿瘤筛查，并且已经报道了一些可能改变生活的诊断结果，例如以前未知的恶性肿瘤。然而，更大规模的患者队列研究将必须证明这种方法的成本效益和临床有效性。对于初始肿瘤分期，PET-CT已被证明在定义T分期和评估淋巴结方面更准确，主要是因为WB-MRI中缺少代谢信息。然而，新的应用，如磁共振全身扩散加权成像或亲淋巴造影剂，可能在不久的将来显著提高敏感性。全身磁共振成像在检测远处转移性疾病方面显示出优势，特别是对于那些经常扩散到肝脏或大脑的肿瘤以及作为全身骨髓筛查应用。在此背景下，WB-MRI在检测骨骼转移和多发性骨髓瘤分期方面高度准确。本文总结了CT/PET-CT和WB-MRI的最新进展，并强调了它们在全身肿瘤成像范围内的性能。
