Division of Internal Medicine, Department of Internal Medicine and Gastroenterology, University of Bologna, Bologna, Italy.
Hepatol Res. 2007 Sep;37 Suppl 2:S178-92. doi: 10.1111/j.1872-034X.2007.00183.x.
In the last decade, new imaging techniques have become available, offering the possibility of investigating contrast perfusion of liver nodules in cirrhosis. It is now accepted that a non-invasive diagnosis of hepatocellular carcinoma (HCC) can be established based on the vascular pattern, obtained with pure blood pool contrast agents. The diagnostic pattern includes: hypervascularity in the arterial phase (15-35 s after contrast injection), consisting in a contrast signal in the nodule greater than in the surrounding parenchyma, followed by contrast wash out, which leads the nodule to show the same, or, more specifically, a lower contrast signal, than the surrounding parenchyma in the portal and late phases (>40 s after injection). Such a pattern can be obtained not only by computed tomography or magnetic resonance imaging, but also by contrast-enhanced ultrasonography, most simply with real-time low mechanical index harmonic imaging ultrasound equipment with second-generation ultrasound contrast agents. The risk of false-positive diagnosis of malignancy isnearly abolished when the functional vascular pattern is not the only feature, but is superimposed on a nodule visible also without contrast. One single contrast imaging technique may suffice to make a diagnosis of HCC if the nodule is >1 cm in diameter and has developed during a surveillance program. Other types of contrast agents, such as those taken up by the reticular-endothelial system cells, may offer additional diagnostic clues, but definitive evidence of their efficacy is still to be produced. In conclusion, contrast-enhanced imaging techniques now offer the possibility of a non-invasive diagnosis of HCC in a large number of cases, reducing the need of invasive investigations, such as ultrasound-guided biopsy or angiography.
在过去的十年中，新的成像技术已经出现，为研究肝硬化中肝脏结节的对比灌注提供了可能。现在已经公认，基于纯血池造影剂获得的血管模式，可以对肝细胞癌（HCC）进行非侵入性诊断。诊断模式包括：动脉期（注射造影剂后 15-35 秒）的高血管化，表现为结节的造影信号高于周围实质，随后造影剂洗脱，导致结节在门静脉期和晚期（注射后 40 秒以上）显示与周围实质相同或更具体地说，较低的造影信号。这种模式不仅可以通过计算机断层扫描或磁共振成像获得，也可以通过对比增强超声获得，最简便的方法是使用实时低机械指数谐波成像超声设备和第二代超声造影剂。当功能血管模式不是唯一特征，而是叠加在可见的无对比结节上时，恶性肿瘤的假阳性诊断风险几乎可以消除。如果结节直径>1 厘米并且是在监测计划中发展的，则单一的对比成像技术可能足以诊断 HCC。其他类型的造影剂，如网状内皮系统细胞摄取的造影剂，可能提供额外的诊断线索，但仍需要进一步证实其疗效。总之，对比增强成像技术现在为大量 HCC 提供了非侵入性诊断的可能性，减少了对侵入性检查（如超声引导活检或血管造影）的需求。
