Zech Christoph J, Herrmann Karin A, Reiser Maximilian F, Schoenberg Stefan O
Institute of Clinical Radiology, Munich University Hospitals-Grosshadern, Ludwig-Maximilians-University.
Magn Reson Med Sci. 2007;6(1):43-52. doi: 10.2463/mrms.6.43.
The appropriate staging of malignant tumors is increasingly important as new therapeutic strategies develop. Because metastatic involvement of the liver in extrahepatic malignant disease may significantly change therapeutic approach, it is important to rule out such involvement with high confidence. Moreover, the differentiation between incidental benign lesions, such as hemangioma, focal nodular hyperplasia (FNH), or adenoma, is of high interest. Magnetic resonance (MR) imaging has proved reliable for diagnostic work-up of the liver. Liver-specific contrast agents have been especially helpful in detecting and precisely characterizing focal liver lesions, but the use of these agents has been limited because it has not been possible to perform both proper vascular phase and liver-specific phase within a reasonable time frame and in a single examination after a single injection of contrast agent. However, the hepatobiliary contrast agent gadolinium-ethoxybenzyl (Gd-EOB)-DTPA now allows combined dynamic imaging and hepatocyte-specific imaging in one examination. Gd-EOB-DTPA can be injected as a bolus and shows the enhancement characteristics and vascularity of liver lesions. In the delayed phase, which is acquired most appropriately 20 min after injection, Gd-EOB-DTPA is taken up selectively by functioning hepatocytes. Thus, malignant liver lesions, e.g. metastases, are spared from contrast uptake of the surrounding liver parenchyma. These lesions are hypointense in contrast to the surrounding bright liver. We review the current literature and present a practical approach to Gd-EOB-enhanced MR imaging using imaging examples of patients with liver metastases.
随着新的治疗策略不断发展，恶性肿瘤的恰当分期变得愈发重要。由于肝外恶性疾病发生肝转移会显著改变治疗方法，因此有必要高度可靠地排除这种转移情况。此外，区分诸如血管瘤、局灶性结节性增生（FNH）或腺瘤等偶然发现的良性病变也备受关注。磁共振（MR）成像已被证明在肝脏诊断检查中是可靠的。肝脏特异性对比剂在检测和精确表征肝脏局灶性病变方面特别有帮助，但这些对比剂的使用受到限制，因为在单次注射对比剂后的一次检查中，无法在合理的时间范围内同时进行适当的血管期和肝脏特异性期成像。然而，肝胆对比剂钆塞酸二钠（Gd-EOB）-DTPA现在允许在一次检查中进行联合动态成像和肝细胞特异性成像。Gd-EOB-DTPA可以静脉推注给药，并显示肝脏病变的强化特征和血管情况。在注射后最适宜的20分钟获取的延迟期，Gd-EOB-DTPA被正常运作的肝细胞选择性摄取。因此，恶性肝脏病变，如转移瘤，周围肝实质的对比剂摄取将其排除在外。与周围明亮的肝脏相比，这些病变表现为低信号。我们回顾了当前的文献，并通过肝转移患者的成像实例，介绍了一种Gd-EOB增强MR成像的实用方法。
