探讨分化程度、病灶大小、肝病背景对肝细胞癌（HCC）超声造影廓清过程的影响。

回顾性分析2005年1月至2015年6月第三军医大学西南医院行超声造影检查动脉相呈均匀或不均匀高增强并经手术标本或穿刺活检病理证实的HCC患者403例。所有病例均为单发病灶。将肿瘤廓清的模式分为动脉相、门脉相、延迟相开始廓清及不廓清。其中高、中、低分化HCC分别为115、156、132例；常规超声测得肿瘤最大径≤3.0 cm、3.1~5.0 cm、>5.0 cm分别为116、154、133例；肝硬化239例，非肝硬化164例。采用R×C表的χ²检验比较不同分化程度、不同大小HCC各廓清模式所占比例差异，进一步组间两两比较采用Pearson χ²检验；采用Pearson χ²检验比较不同肝病背景HCC各廓清模式所占比例差异。

403例HCC患者，不同分化程度的HCC在动脉相开始廓清的比例差异无统计学意义。高分化组HCC在门脉相开始廓清的比例均低于中分化组、低分化组HCC，高分化组HCC延迟相开始廓清、不廓清的比例均高于中分化组、低分化组HCC，且差异均有统计学意义（门脉相：χ²=10.358、43.789，P均<0.01；延迟相：χ²=5.134、P<0.05，χ²=13.069、P<0.01；不廓清：χ²=8.669、25.899，P均<0.01）。中分化组HCC在门脉相开始廓清的比例低于低分化组HCC，不廓清的比例高于低分化组HCC，且差异均有统计学意义（门脉相：χ²=8.847；不廓清：χ²=7.396，P均<0.01）；但是中分化组HCC与低分化组HCC在延迟相开始廓清的比例差异无统计学意义。不同大小的HCC在动脉相、门脉相、延迟相开始廓清及不廓清的比例差异均无统计学意义。肝硬化背景与非肝硬化背景HCC在动脉相、门脉相、延迟相开始廓清及不廓清的比例差异均无统计学意义。

肝病背景及病灶大小对HCC超声造影开始廓清的时相无明显影响，不同分化程度HCC超声造影开始廓清的时相具有一定的差异，高分化HCC大部分表现为延迟相开始廓清或不廓清，进行超声造影检查时应适当延长扫查时间以提高诊断的准确性。超声造影有助于对肝脏肿瘤的定性诊断及病理分级，为临床治疗提供依据。

To investigate the influence of the cellular differentiation, the tumor size and the hepatic background on the washout of hepatocellular carcinoma (HCC) in contrast-enhanced ultrasound (CEUS).

All 403 cases of single HCC with arterial hyperenhancement (homogeneous or heterogeneous) who underwent CEUS examination in Southwest Hospital Affiliated to Third Military Medical University and were pathologically demonstrated as HCC by surgery or needle biopsy from January 2005 to June 2015 were retrospectively enrolled. Four washout patterns were classified according to the start time of washout: washout in arterial phase, washout in portal phase, washout in delayed phase and no washout. According to the cellular differentiation, the patients were grouped as well differentiated HCCs (n=115), moderately differentiated HCCs (n=156) and poorly differentiated HCCs (n=132). Based on the tumor size measured by ultrasound, the patients were divided into three groups: ≤3 cm (n=116), 3.1-5 cm (n=154) and >5 cm (n=133). On the basis of pathology, the background of liver were divided into cirrhosis (n=239) and non-cirrhosis (n=164). R×C table χ² test was used to analyze the proportion of different washout patterns among different cellular differentiation groups or different tumor size groups, and Pearson χ² test was used in the further two-two comparison among groups. Pearson χ² test was used to analyze the percentage of four washout patterns between cirrhosis and non-cirrhosis groups.

Of 403 cases, the percentage of initial washout occurring in arterial phase was not significantly different among different cellular differentiation HCCs. Well differentiated HCCs had significantly lower percentage of washout firstly emerging in portal phase and significantly higher percentage of washout firstly emerging in delayed phase or no washout when compared with moderately or poorly differentiated HCCs (portal phase: χ²=10.358 and 47.398, both P< 0.01; delayed phase: χ²=5.134, P<0.05, χ²=13.069, P<0.01; no washout: χ²=8.669 and 25.899, both P<0.05). The percentage of washout firstly occurring in portal phase of moderate differentiation lesions was significantly lower and the percentage of no washout of moderate differentiation lesions was significantly higher when compared with poor differentiation lesions respectively (portal phase: χ²=8.847; no washout: χ²=7.396; both P<0.01), while the percentage of washout firstly occurring in delayed phase was not statistically significant. There were no significant differences for the percentage of different washout patterns among the three groups of various size. The percentage of different washout patterns was not statistically different between cirrhosis and non-cirrhosis groups.

The tumor size and the background of liver did not influence the washout of HCC on CEUS. The percentage of different washout patterns differs significantly among different cellular differentiation lesions. Most well differentiated HCC displayed late washout or non-washout. So extended observation is necessary as late washout or sustained enhancement usually occur in most well differentiated HCCs. CEUS is useful for the diagnosis and classification of HCCs.