Imaging of malignant liver masses: characterization and detection

Noninvasive characterization of focal liver lesions is largely based on their enhancement patterns on contrast-enhanced imaging. The use of microbubble contrast agents combined with specialized ultrasound (US) techniques has significantly expanded the role of US in the diagnosis of focal liver lesions based on their vascularity and specific enhancement features. With the advantage of real-time scanning, contrast-enhanced ultrasound (CEUS) can evaluate small lesions that are indeterminate on computed tomography (CT) or magnetic resonance imaging (MR), because CEUS is far less affected by timing issues. Hepatocellular carcinoma is typically characterized by increased arterial flow with frequent dysmorphic tumor vessels and decreased portal venous flow. However, negative enhancement in the portal phase is often not obvious until late (>2 minutes). On the other hand, metastasis shows prompt brief arterial hypervascularity, with either a rim or diffuse pattern and rapid washout, seen as perfusion defects during the portal venous phase. This pattern of complete rapid washout of metastases within the homogeneously enhanced background liver parenchyma can improve their detection and also improve differentiation from hepatocellular carcinoma or benign focal lesions. All malignant lesions generally show negative enhancement or washout during the extended portal venous phase, and this pattern is useful to differentiate them from benign lesions. Microbubble agents, confined to the intravascular space, may infrequently characterize malignancy by showing washout whereas CT or MR shows persistent enhancement due to interstitial distribution.     

超声造影对Budd-Chiari综合征合并肝脏局灶性结节的鉴别诊断价值

目的 探讨Budd-Chiari综合征(BCS)合并肝脏局灶性结节的超声造影鉴别诊断要点.方法 回顾性分析36例BCS合并肝局灶性结节患者的常规超声及超声造影图像,并结合临床病理检查和增强CT及MRI成像等其他影像学检查资料分析.结果 36例BCS患者中11例合并肝癌结节,25例合并增生结节.其中BCS合并肝癌结节超声造影模式为典型的"快进快出",BCS合并增生结节的超声造影表现是多样化的,可分为3型.Ⅰ型增生结节超声造影3个时相与周围肝实质相比均呈等增强;Ⅱ型和Ⅲ型虽然造影特点不同,Ⅱ型动脉相呈离心性增强,Ⅲ型动脉相呈环状向心性增强,但延迟相均较周围肝实质呈等增强或部分高增强.结论 BCS合并肝脏局灶性结节超声造影表现呈多样化,超声造影对鉴别结节良恶性有重要价值.     

Magnetic resonance of focal liver lesions in hepatic cirrhosis and chronic hepatitis.

Detection of focal liver nodules in patients with cirrhosis continues to be a radiologic challenge despite progressive advances in liver imaging in the past 2 decades. Patients with hepatic cirrhosis have a high predisposition to develop hepatocellular carcinoma (HCC), and the early detection and diagnosis of this tumor is very important because the most effective treatment is surgical resection, transplantation, or local ablation therapy when the tumor is small. Cirrhotic livers are mainly composed of fibrosis, together with a broad spectrum of focal nodular lesions ranging from regenerative nodules to premalignant dysplastic nodules to overt HCC. Awareness of such lesions and interpretation of imaging studies in these patients requires a critical review to detect subtle tumors, and a thorough understanding of the imaging appearance of the malignant and benign masses that can occur in the cirrhotic liver. Although the recent advances in liver imaging techniques, especially computed tomography (CT) and magnetic resonance (MR), have facilitated the detection and characterization of focal liver nodules in cirrhotic patients, discriminating between HCC and precancerous nodules remains problematic with all available imaging techniques. Nevertheless, MR imaging appears to have more potential than other imaging techniques in the study of cirrhotic patients and MR may be more appropriate than the other imaging modalities for the detection of small HCCs. In this article we review the imaging characteristics of nodular focal lesions that arise in cirrhotic livers, with special attention to MR imaging features.     

肝癌伴门静脉癌栓血流动力学变化及CT表现的研究

目的：探讨肝癌门静脉癌栓时肝脏血流动力学改变及其影像特征，为肝癌的诊治和预后判断提供帮助。材料和方法：经临床证实并行全肝螺旋CT双期增强扫描的原发性肝癌伴门静脉癌栓32例，不伴门静脉癌栓54例，分别观察动脉期和门脉期癌旁与较远处肝实质及肝癌结节的密度变化。结果：18例肝癌伴门静脉分支癌栓，动脉期主要表现肝动脉血流高灌注，相应受累肝实质呈现斑片状、弧圈形或楔形高密度影，门脉期也见少许楔形高密度影；14例主门静脉主干癌栓和54例门静脉无癌栓，绝大多数全肝密度均匀一致；门静脉有无癌栓组间，灌注异常出现率不同；门静脉癌栓时肝癌的血供分型发生变化，门脉供血型和双重供血型明显减少。结论：肝癌伴门静脉癌栓可影响肝脏的血流动力学改变，引起肝癌结节和周围非癌肝实质的灌注异常，产生特征性的CT表现。     

超声造影与增强螺旋CT诊断肝硬化背景下≤2 cm结节样病灶的比较研究

目的 探讨超声造影(contrast-enhanced ultrasound,CEUS)与增强螺旋CT(contrast-enhanced helical computed tomography,CECT)对肝硬化背景下≤2 cm结节样病灶的诊断效能.方法 对72例81个肝硬化背景下常规超声检查可疑肝内小占化病变者(最大直径≤2 cm)进行CEUS和CECT检查(两者间隔时间≤2周),将两种检查的术前诊断与病理结果进行比较分析,评估两种检查方法的诊断效能.结果 81个病灶53个为肝细胞癌(HCC),26个增生结节,2个血管瘤.53个HCC中,CEUS 51个(96.2%)病灶动脉期呈高增强,CECT 41个(77.4%)病灶动脉期显示强化,CEUS与CECT在显示动脉期血供方面差异有统计学意义(P<0.01).以病灶动脉期呈高增强,门脉期或延迟期消退为低增强作为诊断HCC的标准,CEUS诊断小结节样病灶的敏感性、特异性、准确性分别为86.8%、82.1%、85.2%.CECT分别为73.6%、92.9%、80.2%(P>0.05).结论 CEUS对≤2 cm HCC动脉期血供的显示率高于CECT,CEUS对肝硬化背景下小结节样病灶的诊断能力与CECTT相似.     

Early detection and characterization of hepatocellular carcinoma: value of imaging multistep human hepatocarcinogenesis

The method for early detection of hepatocellular carcinoma (HCC) has been well established in Japan, by means of regularly screening patients at risk for developing HCC by imaging and serological markers of tumor. The principal screening protocol includes performing ultrasonography (US) every 3 months and testing for tumor markers every month in patients at high risk for HCC. There has been another important issue of accurate characterization of nodular lesions found in cirrhotic liver. This problem has been solved by the development of imaging modalities such as US angiography with intra-arterial injection of CO(2), computed tomography during hepatic arteriography and computed tomography during arterial portography. It is most important to differentiate the typical hemodynamic patterns of a low-grade dysplastic nodule having arterial hypovascularity with portal perfusion preserved from those of HCC characterized by arterial hypervascularity with decreased portal perfusion. At present, these findings are easily obtained by contrast-enhanced phase invasion harmonic imaging, which is a noninvasive US technology.     

Solid focal liver lesions indeterminate by contrast-enhanced CT or MR imaging: the added diagnostic value of contrast-enhanced ultrasound

The main clinically recognized application of contrast-enhanced US (CEUS) with microbubble contrast agents is the characterization of incidental focal liver lesions. CEUS with low transmit power insonation allows the real-time assessment of contrast enhancement in a focal liver lesion after microbubble contrast agent injection, during the arterial (10-25 s), portal venous (from 35 s up to 2 min) and late phase (4-6 min after microbubble injection). During the portal venous and late phase benign lesions appear hyper or iso-enhancing in comparison to the adjacent liver parenchyma, while malignant lesions prevalently present contrast washout with hypo-enhancing appearance. CEUS may provide an added diagnostic value in those incidental focal liver lesions in which contrast-enhanced CT or MR imaging are not conclusive. In particular, CEUS may provide an added diagnostic value in those focal liver lesions appearing indeterminate on single-phase CT scan, or on CT scans performed by an incorrect delay time or also after injection of a low dose of iodinated contrast agent, or also in those focal liver lesions revealing equivocal enhancement patterns on contrast-enhanced CT or MR imaging. CEUS may have an added diagnostic value also in hepatocellular nodules in a cirrhotic liver and can be considered a complementary imaging technique to CT.     

肝脏局灶性病变MR动态增强扫描的临床应用

目的：探讨肝脏局灶性疾病ＭＲ动态增强扫描的方法和临床应用。方法：回顾性分析６８例肝脏局灶性病变：包括原发性肝细胞癌２４例,周围型肝管细胞癌２例,转移瘤１６例,海绵状血管瘤２４例,局灶性结节增生２例。     

增强CT定量分析联合肿瘤标志物检测对肝细胞肝癌与局灶性结节增生的鉴别诊断意义

目的探讨增强CT定量分析联合肿瘤标志物检测对肝细胞肝癌(HCC)与局灶性结节增生(FNH)的鉴别诊断价值。方法选择2016年1月至2018年12月90例肝脏占位病变患者(HCC52例、FNH38例)进行回顾性分析,所有患者均接受增强CT检查和进行肿瘤标志物甲胎蛋白检测,观察两组患者的平扫CT值、动静脉期强化CT值、病灶动静脉期CT值与同期肝实质CT值的比值、甲胎蛋白水平。结果HCC组平扫CT值、静脉期CT值、动脉期CT值、静脉期强化CT差值、动脉期强化CT差值均显著低于FNH组,差异有统计学意义(P<0.05);HCC组静、动脉期与肝实质的比值均显著低于FNH组,差异有统计学意义(P<0.05);HCC组AFP水平显著高于FNH组,差异有统计学意义(P<0.05);增强CT定量联合AFP检测肝细胞肝癌的灵敏度和特异度(88.00%、60.34%)均高于单独增强CT定量分析(75.00%、81.57%)及AFP检测(69.23%、65.79%)。结论增强CT定量分析联合肿瘤标志物检测对HCC和FNH鉴别具有较高价值,可提高诊断准确性。     

双动脉期螺旋CT扫描在肝细胞癌诊断中的应用

目的比较双动脉（DAP）、门静脉三期与常规动、门双期CT增强扫描在肝细胞癌诊断中的应用。方法对60例临床实验室检查AFP均为阳性的患者,分别行常规动、门双期CT增强扫描及双动脉、门静脉三期CT增强扫描。常规动、门双期扫描方法以动脉期20～25s,门静脉期35～40s。双动脉、门静脉三期扫描方法以动脉早期（EAP）17～20s,动脉晚期（LAP）25～30s,门静脉期为35～40s扫描。分析两种扫描方法所得全部病灶的各期CT表现,评价两种检查方法对肝细胞癌（HCC）,尤其是小肝癌病灶的检出率及准确性。结果常规双期扫描与双动脉、门脉三期扫描检查在HCC诊断的阳性检出率分别89．6％和97．7％,DAP检查小病灶准确性高于常规动、门双期,二组资料的差异具有统计学意义。结论双动脉、门静脉三期CT增强扫描对诊断肝细胞癌尤其是小肝癌有较高的临床应用价值。     

实时灰阶超声造影和螺旋CT诊断肝肿瘤的比较研究

目的比较实时超声造影和螺旋CT显示肝肿瘤血流信号的特点.方法对29例肝肿瘤(原发性肝癌16例,转移性肝癌2例,血管瘤6例和肝局灶性结节增生5例)分别进行超声造影和CT检查.结果超声造影显示肝恶性肿瘤的整体型、血管瘤的周边型及局灶性结节增生的中央型出现率显著高于其他病变(P<0.01).CT示恶性肿瘤中94.4%(17/18) 动脉期强化、门脉期低密度;血管瘤中83.3%(5/6)呈结节状强化;肝局灶性结节增生动脉期均明显强化.超声造影和CT鉴别肝肿瘤的能力无显著差异.结论超声造影和CT都能敏感地显示不同肝肿瘤的血供特征.     

肝细胞性肝癌超声造影的增强模式 --低机械指数连续实时成像技术的应用研究

目的　分析采用低机械指数连续实时成像技术时肝细胞性肝癌 (HCC)超声造影的增强模式。方法　 6 8例 HCC患者共 72个病灶接受了超声造影检查。采用对比脉冲序列 (CPS)成像技术 ,造影剂为 Sono Vue。结果　静脉注射 Sono Vue后 ,全部病灶均可见强化 ,绝大多数病灶 (70 /72 ,97.2 % )增强早于肝实质及门静脉 ;增强形态主要为均匀或不均匀增强 ;增强程度在动脉期高于肝实质 ,门静脉期和肝窦期则低于肝实质 ;动脉期 30 .6 % (2 2 /72 )的病灶可见包膜强化。结论　 HCC在各时相的增强模式具有特征性 ,采用 CPS技术及造影剂 Sono Vue能实时连续地描述 HCC的增强特点。     

Diagnosis of advanced hepatocellular carcinoma using contrast-enhanced harmonic gray-scale imaging with enhancement agents (Levovist): Correlation with helical CT and US angiography

We compared contrast-enhanced harmonic gray-scale imaging with helical CT and US angiography to evaluate vascularity in advanced hepatocellular carcinoma (HCC). Contrast-enhanced harmonic gray-scale imaging using Levovist (Nihon Schering, Tanabe) as the contrast agent and enhanced helical CT were performed on 38 patients with 45 lesions (29 men and 9 women aged 41 to 83 years; mean age, 66 years; mean maximum tumor diameter, 30.5±23.0 mm), and angiography was performed to evaluate 37 lesions from 32 of these 38 patients (24 men and 8 women, aged 41 to 79 years; mean age, 65 years; mean maximum tumor diameter, 27.9±17.9 mm). Contrast-enhanced harmonic gray-scale imaging showed hypervascular enhancement in 41 of the 45 lesions; the other 4 lesions were not visualized as hypervascular because 3 of the them could not be detected with non-enhanced US and the remaining lesion was situated deep in the liver and more than 11 cm from the surface of the body. Helical CT showed areas of high attenuation in 40 of the 45 lesions, leaving the other 5 lesions equivocal, while US angiography achieved positive enhancement in 36 of 37 lesions. Intratumoral vessels were visualized with contrast-enhanced harmonic gray-scale imaging in 25 of the 45 lesions; however; intratumoral vessels were seen in only 4 of the 45 lesions examined with helical CT. In evaluating vascularity in advanced HCC, contrast-enhanced harmonic gray-scale imaging with Levovist was as effective as US angiography and more effective than helical CT. Motion artifacts produced by the heart make it difficult to evaluate vascularity in advanced HCC located in the left lobe of the liver with Doppler sonography. Contrast-enhanced harmonic gray-scale imaging can show intratumoral vessels and hypervascular enhancement of the tumor without motion artifacts, however, even when the tumor is located near the heart or large vessels. Contrast-enhanced harmonic gray-scale imaging is useful for evaluating vascularity in advanced HCC when the tumor can be visualized with non-enhanced US.     

MR imaging in chronic hepatitis and cirrhosis.

The role of magnetic resonance imaging (MRI) in the evaluation of diffuse parenchymal abnormalities of the liver has been expanded by recent technical advances of MR systems as well as the evolution of intravenous contrast media. Currently, MR is undoubtedly the most useful imaging modality for detecting the presence of chronic liver disease. Tailored sequences allow acurate depiction of specific disorders, including steatohepatitis and iron-overload states. Morphologic changes and signal intensity effects not only facilitate the diagnosis of chronic liver disease with MRI but they also help to distinguish between different etiologies, and they assist in staging the histologic severity of certain chronic conditions. Moreover, the faster MRI scanning techniques presently available permit the dynamic assessment of contrast enhancement, which permits improved characterization of focal hepatic lesions, including regenerative nodules, dysplastic nodules, and hepatocellular carcinoma (HCC). Although overlap in MRI findings still may exist among different types of chronic liver disease and among focal liver lesions, familiarity with certain specific imaging features may be diagnostic in the proper clinical setting. Finally, comprehensive MRI examination, including MR angiography and MR cholangiography, is the most sensitive and cost-effective technique for detecting extrahepatic disease, diagnosing vascular disorders, and evaluating the patient before or after liver transplantation. This article focuses on the current role of MR imaging in patients with chronic liver disease. The subjects covered include the detection and characterization of chronic hepatitis and cirrhosis, specific findings seen in steatohepatitis and certain metabolic diseases, the evaluation of extrahepatic vascular complications of cirrhosis, and patient assessment before and after liver transplantation. The characterization of hepatic masses is also included briefly. This subject is covered in greater depth elsewhere in this issue.     

原发性肝细胞癌患者根治术前预后多因素CT分析

目的 探讨原发性肝细胞癌(HCC)患者根治术前增强CT影像学征象与其预后的关系. 方法 回顾性分析87例接受根治切除术的原发性HCC患者术前临床及双期增强CT影像学资料,分析CT征象及根治术后复发转移及生存情况.采用Kaplan-Meier法,Log-rank时序检验进行单因素生存分析,将有统计学意义的指标依次引入Cox比例风险模型进行多因素分析. 结果全组1、3、5年术后生存率分别为80.18%、65.48%和42.09%.单因素生存分析显示,肿瘤大小、部位(单段病灶与多段病灶)、子灶、血管侵犯、动脉期肿瘤与肝实质CT值比值、门静脉期肿瘤与肝实质CT值比值对预后有影响(P<0.05).多因素Cox回归分析表明,血管侵犯、门静脉期肿瘤与肝实质CT值比值(<0.85)为影响预后的独立因素(P=0.037、0.007). 结论原发性HCC患者根治术后预后不良的主要CT征象包括血管侵犯和门静脉期肿瘤与肝实质CT值比值<0.85.     

多层螺旋CT对肝细胞癌合并门静脉癌栓的诊断价值

目的：探讨多层螺旋CT扫描对肝细胞癌合并门静脉癌栓的诊断价值.材料与方法：回顾性分析25例经手术病理证实的肝细胞癌合并门静脉癌栓患者的三期动态增强CT表现,通过兴趣区（Region of interest,ROI）分析定性和定量评估肿瘤动脉期、静脉期和延迟期图像.另外也通过ROI分析定量评价肝左叶和右叶背景强化情况.结果：定性分析发现40％（10/25）的肝细胞癌表现为动脉期快速不均质血管强化,而64％（16/25）的肿瘤表现为门脉期快速洗脱,另外40％（10/25）的肝细胞癌表现为动脉期快速不均质血管强化和门脉期快速洗脱.定量分析提示动脉期血管强化肝细胞癌从强化前到动脉期的绝对增强值为49.1 ±17.1HU,而动脉期无血管强化肿瘤为23.8±16.6HU,差异具有统计学意义（P＜0.01）.动脉期血管强化肝细胞癌的肝实质背景在动脉期的绝对增强值为13.79±7.9HU,而动脉期无血管强化肿瘤的肝实质背景为36.6±30.6HU,差异具有统计学意义（P=0.03）.结论：很大一部分合并门静脉癌栓的肝细胞癌缺乏特征性的动脉期快速不均质血管强化,可能是背景肝实质动脉血供继发性代偿增加所致,这是应用影像学标准诊断肝细胞癌的一个潜在陷阱.     

肝脏局灶性结节增生的CT表现及鉴别诊断

目的分析肝脏局灶性结节增生(FNH)的CT表现和诊断价值。方法分析经病理证实的肝脏局灶性结节增生25例(34个病灶)CT影像资料。结果21例单发病灶,4例多发病灶。32个病灶呈稍低密度,2个病灶为等密度,增强扫描动脉期显著强化,门脉期呈持续高密度强化或呈等密度,延迟期病灶为等密度或略低密度,13个病灶有纤维分隔或瘢痕。结论CT双期扫描对能够正确诊断大部分肝脏局灶性结节增生病例。     

螺旋CT双期扫描诊断伴肝硬化的小肝癌的探讨

目的：探讨螺旋CT双期增强扫描诊断伴肝硬化的小肝癌的价值。方法：14例伴肝硬化的小肝癌患手术及病理发现小肝癌病灶21个（直径≤3cm),回顾性分析螺旋CT双期增强扫描的结果,比较小肝癌在动脉期和门脉期内强化类型,检出率及诊断正确率,结果：动脉期检出率为85．7％（18／21）,门脉期有71．4％（15／21）,66．7％小肝癌动脉期为均一高密度,门脉期定性正确率为52．4％,联合动脉期和静脉期后,其检出率和定性正确率分别增加至90．5％和80．9％。结论：动脉期扫描明显增加小肝癌的检出,两期结合能提高检出率及定性正确率。     

Role of Contrast‐Enhanced Ultrasonography in Primary Hepatic Lymphoma

Objective. Ultrasonography is the first examination performed for screening of hepatocellular carcinoma (HCC); contrast‐enhanced ultrasonography (CEUS) can help discriminate between HCC and other lesions. Primary hepatic lymphoma (PHL), even if rare, should be considered in the differential diagnosis of focal liver lesions (FLLs). Few data are available in the literature about the role of CEUS in the diagnosis of PHL; we tried to determine whether CEUS could have a role in this setting. Methods. we describe 2 cases of primary non‐Hodgkin lymphoma of the liver associated with hepatitis B virus (HBV) infection. The first patient was a 62‐year‐old man who was an HBV‐inactive carrier, and the second was a 58‐year‐old man with type 2 diabetes and chronic HBV hepatitis. Results. in both cases, ultrasonography showed a hypoechoic liver lesion (4 and 3 cm, respectively) with irregular margins in segment 4 of the liver. On CEUS, these lesions were inhomogeneously hyperenhanced in the arterial phase and hypoenhanced in the portal and late phases. Contrast‐enhanced computed tomography (CT) in both patients showed slight hyperenhancement in the arterial phase and hypoenhancement in the remaining phases. Needle biopsy showed marginal zone B‐cell lymphoma of the mucosa‐associated lymphoid tissue type in both patients. Conclusions. Contrast‐enhanced ultrasonography and CT did not help us differentiate PHL from HCC; in fact, in both cases we saw the characteristic findings of primary HCC. Primary hepatic lymphoma is a rare condition, but it should always be considered in the differential diagnosis of FLLs. We stress the important role of liver biopsy when imaging indicates HCC in patients without underlying cirrhosis.     

SonoVue超声造影在肝良性占位病变诊断中的应用

目的探讨超声造影在肝良性占位病变诊断中的应用。方法30例肝良性占位病变患者经肘部静脉团注SonoVue。采用超声造影二次谐波成像技术,实时观察注射造影剂后病灶增强特征。结果经超声造影后,23个肝血管瘤动脉相均呈高回声增强,20个(87%)表现为周边向心型,2个(8.7%)为中央扩散型,1个(4.3%)为整体型增强特征,20个病灶在门脉相和延迟相仍为高回声增强,2个病灶渐变为等回声增强,1个病灶渐变为低回声增强。2个肝局灶性结节增生病灶在动脉相均呈中央扩散型增强,表现为轮辐状,门脉相及延迟相呈等回声增强。3个肝局部脂肪缺失病灶均显示动脉相无增强,门脉相及延迟相呈等回声。2个肝脓肿病灶动脉相周边无增强,延迟相病灶内呈低回声增强及无增强。结论SonoVue超声造影二次谐波成像技术能动态显示病灶增强特征,有助于肝良性占位病变的诊断及鉴别诊断。