LU, MD, DMSc Ming-De

Ming-De LU, MD, DMSc

Sun Yat-Sen University, China

キーワード :

The status of medical care in ultrasound （US） between Chinese Mainland and Japan is quite difference although they are so close geographically. Chinese US Specialists undertake all of examination works since the system of Medical Sonographer has not yet been established. China is a major country of liver disease with 90 million carriers of hepatitis B virus （HBV） and 20 million patients of chronic virus hepatitis. Primary liver cancer is the second most common malignancy in China with yearly 400,000 new cases and 370,000 deaths, accounting for 54％ and 53％ of the total cases and deaths of liver cancer worldwide. Chinese US Specialists have made a great contribution to the surveillance, diagnosis and treatment of liver diseases.
Since 2004 contrast-enhanced ultrasound （CEUS） with sulfur hexafluoride （SF₆）-filled microbubble （SonoVue^®） and non-linear imaging at low acoustic power has been applied in China with yearly more than 100,000 examinations performed. CEUS turns a new page in liver US, becoming a confident tool for characterization of focal liver lesions （FLLs）. Along with accumulation of the experience in liver CEUS some notable findings have emerged. Infected FLLs are difficult to be identified where most lesions show enhancement features similar to malignancy. One third of focal nodular hyperplasia （FNH） is observed untypical enhancement pattern. With regard to enhancement appearances of hepatocellular carcinoma （HCC） 69％ of the arterial hyper-enhancing lesions wash contrast out in portal vein phase which is different from that presented in west countries. In a large series with pathologically proven 1,120 cases of HCC and 119 of intrahepatic cholangiocarcinoma （ICC）, the lesions in cirrhotic liver showing arterial hypervascularity followed by rapid contrast washout account for 88％ in HCC and 100％ in ICC （P=0.097）. In ICC, 35％ of the patients are co-existence of liver cirrhosis or HBV infection. Peripheral rim-like enhancement is found 50％ in ICC and only 1％ in HCC （p<0.001）. These results indicate that diagnosis of HCC using CEUS should carefully distinguish from ICC and peripheral rim-like enhancement is a clue for differentiation. Based on the results of a nationwide multicentre prospective study and comprehensive literature surveys, a clinical practice guideline for liver CEUS conformed to the situation in China will be issued by the Chinese Ultrasound Doctor Association （CUDA）.
Unlike most of countries, medical ultrasonics in Chinese hospitals is an independent department not belonged to radiology. The US Specialists are a major force in implementation of US-guided percutaneous ablation therapies for liver cancer and a part of hospitals have set up dedicated division of interventional US. Radiofrequency （RF） and microwave （MW） energy delivery based ablations are currently mainstream modalities. US Specialists have actively introduced innovative imaging techniques, such as CEUS and fusion image combining US and CT/MRI, for assistance of precisely targeting in tumor poorly detectable on baseline US or those difficult to access. Use of CEUS to evaluate local response to tumor ablation has been documented that its diagnostic ability is comparable to CECT/CEMRI. Two randomized controlled trials from China demonstrate that in treatment of patients with HCC meeting Milan criteria, US-guided percutaneous RF or MW ablation and surgical resection have similar long-term outcomes but the treatment-related morbidity and hospital stay are markedly less in ablation than that in resection. Nevertheless whether percutaneous ablation therapy can be as the first line approach for early stage HCC is still very controversial. So far majority of the HCC in China are at advanced stage when diagnosed, thus US-guided percutaneous ablation is more frequently applied to recurrence post hepatectomy. Repeated ablation for treatment of recurrent HCC in selected patients is able to achieve 5-, 7- and 10-year overall survival of 66％, 52％ and 36％, respectively after initial resection.