Application of contrast-enhanced ultrasound after livertransplantation:Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents(UCAs), in combination with contrastspecific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and posttransplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrastenhanced ultrasound applications in liver transplantation.

Detection of focal liver lesions in cirrhotic liver using contrast-enhanced ultrasound

Patients with liver cirrhosis are at increased risk of hepatocellular carcinoma(HCC).Conventional or baseline ultrasound(BUS)is often used as the first-line tool for HCC surveillance or detection,but the accuracy of BUS in HCC detection or differentiation from other focal liver lesions(FLLs)is limited.Contrast-enhanced ultrasound(CEUS)represents a recent revolution in the field of ultrasonography and it has become increasingly important in the detection and evaluation of FLLs.In CEUS,HCC typically exhibits arterial hyper-enhancement and portal-venous washout represented by hypoenhanced lesions in the portal venous and late phases.The detection rate of HCC was significantly higher with CEUS compared with BUS.Even regenerative or some dysplastic nodules may exhibit arterial hyperenhancement as they are differentiated from HCC by its iso-enhancing pattern in portal and late phases.The contrast-enhancement patterns of other different types of benign and malignant FLLs,as well as their detection rates with CEUS,were also discussed.

Clinical Value of Contrast-enhanced Ultrasound in Differentiating Benign and Malignant Focal Liver Lesions

To explore the clinical value of contrast-enhanced ultrasound （CEUS） in differentiating benign and malignant focal liver lesions （FLLs） with SonoVue, CEUS was used to examine 113 patients with focal liver lesions （FLLs） in our hospital during July 2005 to December 2006. All the patients underwent contrast-enhanced CT （CECT） or contrast-enhanced MRI （CEMRI）. Except for patients with focal fatty sparings （n=18） and with hemangiomas （n=8）, all the patients were confirmed by operation or ultrasonic-guided liver puncture biopsy. A sulfur hexafluoride gas-based contrast agent was used with a MI of 0.15 to 0.17. Forty-eight cases of malignant FLLs, including 30 hepatocellular carcinomas （HCCs）, 2 cholangiocarcinomas and 16 metastatic tumors, were detected. Seventy-eight cases of benign FLLs, including 33 hemangiomas, 9 focal nodular hyperplasias （FNHs）, 19 focal fatty sparings, 5 abscesses, 7 regenerative nodules and 2 inflammatory pseudo-tumor, were involved. The contrast pattern of benign and malignant FLLs was quite different. CEUS has higher specificity and sensitivity than conventional ultrasound in differentiating benign and malignant FLLs.

Hemodynamic Changes on Color Doppler Flow Imaging and Intravenous Contrast-enhanced Ultrasound for Assessing Transplanted Liver and Early Diagnosis of Complications

The value of color Doppler flow imaging （CDFI） and intravenous contrast-enhanced ultrasound （CEUS） for assessing the transplanted liver and early diagnosing complications by examining hemodynamic changes was discussed. Seventy-five patients with orthotopic liver transplantation （OLT） underwent CDFI. The following parameters were measured： peak systolic velocity （PS）, resistance index （RI） and Doppler perfusion index （DPI） of the hepatic artery （HA）, time average velocity （TAV） of portal vein （PV） and velocity of hepatic vein （HV） in different stages postoperation, And 11 patients of them received CEUS. Thirty healthy subjects were enrolled as controls, The results showed that： （1） In 23 patients without obvious complications, TAV of PV within 15 days post-operation was significantly higher than in controls （P〈0.05）, PS and DPI of HA within 7 days postoperation were lower, but RI was higher than in controls （P〈0.05）; （2） When the hepatic artery thrombosis （HAT） occurred, PS and DPI of HA were obviously decreased, but TAV of PV significantly increased like a high saw-tooth wave; （3） While rejection occurred, both TAV of PV and PS of HA were decreased with the increase in RI of HA, and the triphasic wave of HV disappeared and displayed as saw-tooth wave; （4） The incidence of biliary complications in liver transplantation was increased when DPI was reduced; （5） Seven cases of hepatic carcinoma relapse after OLT demonstrated hyperecho in the arterial phase and hypoecho in the portal and later phase on CEUS; （6） In 2 cases of HA thrombus, there was no visualized enhancement in arterial phase of CEUS, but enhancement during the portal vein and parenchymal phase. It was concluded that the hemodynamic changes of PV, HA and HV in the transplanted liver are valuable for assessing the transplanted liver and early diagnosing complications on CDFI and CEUS.

Contrast-enhanced ultrasound in diagnosis and characterization of focal hepatic lesions

The extensive use of imaging techniques in differential diagnosis of abdominal conditions and screening of hepatocellular carcinoma in patients with chronic hepatic diseases,has led to an important increase in identification of focal liver lesions.The development of contrastenhanced ultrasound(CEUS) opens a new window in the diagnosis and follow-up of these lesions.This technique offers obvious advantages over the computed tomography and magnetic resonance,without a decrease in its sensitivity and specificity.The new second generation contrast agents,due to their intravascular distribution,allow a continuous evaluation of the enhancement pattern,which is crucial in characterization of liver lesions.The dual blood supply in the liver shows three different phases,namely arterial,portal and late phases.The enhancement during portal and late phases can give important information about the lesion's behavior.Each liver lesion has a different enhancement pattern that makes possible an accurate approach to their diagnosis.The role of emerging techniques as a contrastenhanced three-dimensional US is also discussed.In this article,the advantages,indications and technique employed during CEUS and the different enhancement patterns of most benign and malignant focal liver lesions are discussed.

Focal liver lesions in cirrhosis:Role of contrast-enhanced ultrasonography

Contrast-enhanced ultrasound(CEUS)represents a great innovation for the evaluation of focal liver lesions(FLLs).The main advantage of CEUS is the realtime imaging examination and the very low toxicity in patients with renal failure.Liver cirrhosis has been recognized as a major risk factor for the onset of hepatocellular carcinoma(HCC)and intrahepatic cholangiocarcinoma(ICC).HCC in liver cirrhosis develops as the last step of a complex that leads to the gradual transformation from regenerative nodule through dysplastic nodule to HCC.In patients with liver cirrhosis,a surveillance program is recommended consisting of ultrasound(US)for detecting small focal lesions.A wide spectrum of benign and malignant lesions other than HCC may be found in the cirrhotic liver and their differentiation is important to avoid errors in staging diseases that may preclude potentially curative therapies.Several published studies have explored the value of CEUS in liver cirrhosis and they have been shown to have excellent diagnostic and prognostic performances for the evaluation of non-invasive and efficient diagnosis of FLLs in patients at high risk for liver malignancies.The purpose of this article is to describe and discuss CEUS imaging findings of FLLs including HCC and ICC,all of which occur in cirrhotic livers with varying prevalence.

Vascular complications after adult living donor liver transplantation:Evaluation with ultrasonography

Living donor liver transplantation(LDLT) has beenwidely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrastenhanced ultrasound(CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional grayscale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Differentiating malignant and benign focal liver lesions in children using CEUS LI-RADS combined with serum alpha-fetoprotein

BACKGROUND Contrast-enhanced ultrasound(CEUS)can be used to diagnose focal liver lesions(FLLs)in children.The America College of Radiology developed the CEUS liver imaging reporting and data system(LI-RADS)for standardizing CEUS diagnosis of FLLs in adult patients.Until now,no similar consensus or guidelines have existed for pediatric patients to improve imaging interpretation as adults.AIM To evaluate the performance of CEUS LI-RADS combined with alpha-fetoprotein(AFP)in differentiating benign and malignant FLLs in pediatric patients.METHODS Between January 2011 and January 2021,patients≤18 years old who underwent CEUS for FLLs were retrospectively evaluated.The following criteria for diagnosing malignancy were proposed:Criterion I considered LR-4,LR-5,or LRM lesions as malignancies;criterion II regarded LR-4,LR-5 or LR-M lesions with simultaneously elevated AFP(≥20 ng/mL)as malignancies;criterion III took LR-4 Lesions with elevated AFP or LR-5 or LR-M lesions as malignancies.The sensitivity,specificity,accuracy and area under the receiver operating characteristic curve(AUC)were calculated to determine the diagnostic value of the aforementioned criteria.RESULTS The study included 63 nodules in 60 patients(mean age,11.0±5.2 years;26 male).There were no statistically significant differences between the specificity,accuracy,or AUC of criterion II and criterion III(95.1%vs 80.5%,84.1%vs 87.3%,and 0.794 vs 0.902;all P>0.017).Notably,criterion III showed a higher diagnostic sensitivity than criterion II(100%vs 63.6%;P<0.017).However,both the specificity and accuracy of criterion I was inferior to those of criterion II and criterion III(all P<0.017).For pediatric patients more than 5 years old,the performance of the three criteria was overall similar when patients were subcategorized by age when compared to all patients in aggregate.CONCLUSION CEUS LI-RADS combined with AFP may be a powerful diagnostic tool in pediatric patients.LR-4 with elevated AFP,LR-5 or LR-M lesions is highly suggestive of malignant tumors.

High Frame Rate Contrast-enhanced Ultrasound Helps Differentiate Malignant and Benign Focal Liver Lesions

Background and Aims:This study aimed to evaluate the diagnostic performance of high frame rate contrast-en-hanced ultrasound(H-CEUS)of focal liver lesions(FLLs).Methods:From July 2017 to June 2019,conventional con-trast-enhanced ultrasound(C-CEUS)and H-CEUS were per-formed in 78 patients with 78 nodules.The characteristics of C-CEUS and H-CEUS in malignant and benign groups and the differences between different lesion sizes(1-3 cm,3-5 cm,or>5 cm)of C-CEUS and H-CEUS were examined.The diagnostic performance of C-CEUS and H-CEUS was ana-lyzed.The chi-square test or Fisher’s exact test was used to assess inter-group differences.The receiver operating characteristic curve was plotted to determine the diagnostic performance of C-CEUS and H-CEUS.Results:There were significant differences in the enhancement area,fill-in direc-tion and vascular architecture between C-CEUS and H-CEUS for both benign and malignant lesions(all p=0.000-0.008),but there were no significant differences in washout results(p=0.566 and p=0.684,respectively).For lesions 1-3 cm in size,the enhancement area,fill-in direction,and vascular architecture on C-CEUS and H-CEUS were significantly dif-ferent(all p=0.000),unlike for lesions 3-5 cm or>5 cm in size.For differentiation of malignant from benign FLLs in the 1-3 cm group,H-CEUS showed sensitivity,specific-ity,accuracy,and positive and negative predictive values of 92.86%,95.0%,96.3%,90.48%and 93.75%,respectively,which were higher than those for C-CEUS(75.0%,70.0%,77.78%,66.67%and 72.91%,respectively).Conclusions:H-CEUS provided more vascular information which could help differentiate malignant from benign FLLs,especially for lesions 1-3 cm in size.

Ultrasound imaging of abdominal sarcoidosis: State of the art

Since it has been recognized that sarcoidosis(SA) is not an exclusive disorder of the lungs but can also affect other organs such as the liver and spleen, efforts have been made to define specific imaging criteria for the diagnosis of the single organ involvement, and the concept has been reinforced that the exclusion of alternative causes is important to achieve the correct diagnosis. Ultrasound(US)is a useful tool to evaluate patients with suspected abdominal SA, such as of the liver, spleen, kidney, pancreas and other organs, showing findings such as organomegaly, focal lesions and lymphadenopathy. While the diagnosis of abdominal SA is more predictable in the case of involvement of other organs(e.g.,lungs), the problem is more complex in the case of isolated abdominal SA. The recent use of contrast-enhanced ultrasound and endoscopic ultrasound elastography has provided additional information about the enhancement patterns and tissue rigidity in abdominal SA. Here we critically review the role of US in abdominal SA, reporting typical findings and limitations of current evidence and by discussing future perspectives of study.

超声造影对诊断肝移植术后缺血性胆道损伤预测价值的前瞻性队列研究

目的:探究超声造影(CEUS)对肝移植术后早期肝门处胆管壁增厚患者缺血性胆道损伤(ITBLs)的预测价值。方法:前瞻性纳入2020年6月25日至2022年12月28日于首都医科大学附属北京友谊医院肝移植中心行肝移植术且术后早期肝门部胆管壁增厚的45例患者,所有患者在常规超声初次发现肝门处胆管壁增厚时进行胆道CEUS,并记录胆管壁在各时相的强化模式,根据后续胆道造影的结果将患者分为ITBLs组(15例)和非ITBLs组(30例),对两组患者在CEUS各时相的强化程度进行定性分析并比较,同时评价CEUS对肝移植术后ITBLs的诊断效能。结果:两组患者供肝来源、胆道吻合方式、自身免疫性肝病、肝动脉闭塞(HAO)、排异反应、巨细胞病毒感染及胆管炎情况比较差异均无统计学意义(P>0.05)。两组CEUS动脉期增强模式比较,非ITBLs组患者中25例(占83.3%)为高增强,5例(占16.7%)为等增强,0例低增强或无增强;ITBLs组患者中3例(占20.0%)为高增强,4例(占26.7%)为等增强,8例(占53.3%)为低增强或无增强,两组比较差异有统计学意义(χ^(2)=22.946,P<0.05)。两组延迟期增强模式比较差异无统计学意义(P>0.05)。胆道CEUS提示动脉期低增强或无增强诊断ITBLs的准确率、灵敏度、特异度、阳性预测值及阴性预测值分别为84.4%,53.3%,100%,100%和84.4%。8例CEUS诊断为ITBLs患者,CEUS诊断ITBLs的时间较胆道造影提前了1~6[3.0(1~5)]个月。结论:CEUS可以在胆道出现明显的形态学改变前较准确的预测ITBLs,显著提前ITBLs的诊断时间。

超声造影在移植肝脏局灶性低回声病灶鉴别诊断中的应用

目的评价超声造影技术在肝移植术后肝脏局灶性低回声病灶鉴别诊断中的应用价值。方法对肝移植术后肝脏出现局灶性低回声病灶患者,用西门子Sequoia512彩色多普勒超声诊断仪和超声造影剂Sonovue进行超声造影检查,观察3个时相的造影剂灌注模式,并用自动跟踪对比量化技术(Axius ACQ)对病灶及周围肝组织进行定量分析。结果10例出现局灶性低回声病灶的患者中,超声造影明确诊断梗死灶5例(低回声病灶为无增强,ACQ分析无造影剂灌注),非均质脂肪肝3例(低回声病灶在动脉相、门脉相呈高增强,ACQ分析该区域为正常肝组织,周围肝组织为血流灌注不良区域),肝癌复发2例(其特征为动脉相快速均匀高增强,门脉相及延迟相快速消退)。结论超声造影技术能较好评估肝实质的血流灌注分布情况,有助于移植肝脏梗死灶、非均质性脂肪肝及肿瘤复发的鉴别诊断。

实时超声造影在肝脏低回声型病灶鉴别诊断中的应用

目的:探讨实时超声造影技术在肝脏低回声型病灶鉴别诊断中的价值。方法:对常规二维超声发现的75例肝内低回声型病灶先进行彩色多普勒超声检查,后用实时超声造影技术与造影剂SonoVue对病灶进行实时造影检查,最后通过增强CT、MRI与组织病理学来明确病灶性质。结果:75例肝内低回声型病灶,其中有原发性肝癌18例,转移性肝癌12例,血管瘤20例,FNH5例,非均质脂肪肝13例,肝硬化结节7例。普通彩超诊断准确率为80%,超声造影为97%。结论:实时超声造影技术对肝脏低回声型病灶的鉴别诊断有重要价值。

超声造影对移植肝脏局灶性病变的诊断价值

目的:评价超声造影对移植肝脏局灶性病变的诊断价值。方法:对30例移植肝脏局灶性病变患者,用西门子Sequoia512彩色多普勒超声诊断仪和超声对比剂Sonovue进行超声造影检查,观察三个时相的对比剂灌注模式,并用自动跟踪对比量化技术(AxiusACQ)对病灶及周围肝组织进行定量分析。所有病例均经病理及临床随访证实。结果:30例移植肝脏局灶性病变患者,超声造影正确诊断29例,包括肝癌复发18例、非均质脂肪肝5例、肝血管瘤4例、梗死灶2例;超声造影误诊1例,超声造影怀疑肝癌复发,经穿刺活检诊断为局灶性脂肪浸润。结论:移植肝脏局灶性病变具有各自典型的增强模式,超声造影技术有助于移植肝脏局灶性病变的鉴别诊断,具有重要临床价值。

超声造影对移植肝局灶性病变的鉴别诊断价值

目的探讨超声造影对移植肝内局灶性病变的鉴别诊断价值。方法对67例肝移植术后确诊有移植肝内局灶性病变的患者进行超声造影检查,观察不同病变在动脉期、门静脉期和延迟期3个时相的造影剂灌注模式。以延迟期仍保持高增强或等增强或造影中始终无增强判定为良性病变,以延迟期消退为低增强或无增强判定为恶性病变,计算超声造影诊断良性病变与恶性病变的敏感度与假阴性率。结果与良性病变比较,在动脉期表现为高增强或等增强的病灶中,恶性病变在门静脉期或延迟期有显著的增强消退倾向(P<0.01)。超声造影诊断良性病变的敏感度为90%(19/21),假阴性率为10%(2/21),2例假阴性均为肝脓肿;诊断恶性病变的敏感度为100%(46/46)。结论超声造影对移植肝内局灶性病变具有较高的鉴别诊断价值,有助于区别良、恶性病变。

实时超声弹性成像技术对原位肝移植患者术后缺血型胆道病变临床评估价值分析

目的探讨应用实时超声弹性成像技术对原位肝移植术后缺血型胆道病变的临床评估价值。方法 2013年1月～2017年1月在我院接受肝移植患者52例,使用彩色多普勒超声和实时超声弹性成像技术检测门静脉最大截面直径(PVD)、肝动脉阻力指数(HARI)、门静脉流速(PVV)、肝动脉搏动指数(HAPI)、肝动脉收缩期峰值流速(HAV),并测量剪切波速度(SWV)。结果术后6个月复查,胆道病变患者超声检查主要表现为与门静脉左右支伴行的肝内胆管呈管状等回声,彩色多普勒血流成像显示胆管低回声旁门静脉血流信号明显变细;在52例患者中发现缺血型胆道病变10例(19.2%);胆道病变与无胆道病变患者PVV、HAV、HARI和HAPI比较,差异无统计学意义(P>0.05),胆道病变患者PVD显著高于无胆道病变者[(1.1±0.2) cm/s对(0.8±0.3) cm/s,P<0.05];两组血清AST水平差异无统计学意义(P>0.05),但胆道病变患者血清ALP和GGT水平显著高于无胆道病变者(P<0.05);在检测深度分别为4 m和5 cm时,胆道病变患者SWV显著高于对照组,差异均有统计学意义(P<0.05)。结论实时超声弹性成像技术在原位肝移植术后缺血型胆道病变的临床评估方面具有经济、方便、无创、易重复的特点,对病变的监测具有重要的临床意义。

脂肪肝内低回声局灶性病变的声诺维实时造影增强超声定性诊断

目的:应用声诺维实时增强超声造影技术对脂肪肝内低回声局灶性病变进行良恶性鉴别诊断。方法:对用常规超声发现的33例脂肪肝患者的41个肝内低回声局灶性病变进行了超声造影检查,通过增强螺旋CT、M R、组织病理诊断及临床表现来明确病灶性质。结果:共有7个恶性病灶,包括2个肝细胞肝癌,3个转移癌,1个胆管细胞癌和1个何杰金氏淋巴瘤;良性病灶34个,包括11个血管瘤,5个局灶性结节增生(FNH),18个非均匀性脂肪肝。通过超声造影,34个良性病灶中的33个及7个恶性病灶全部被正确定性诊断。结论:声诺维实时超声造影增强技术能对脂肪肝内局灶性低回声病变进行良恶性鉴别诊断。

CEUS: A new imaging approach for postoperative vascular complications after right-lobe LDLT

AIM: To investigate contrast-enhanced ultrasound (CEUS) for early diagnosis of postoperative vascular complications after right-lobe living donor liver transplantation (RLDLT). METHODS: The ultrasonography results of 172 patients who underwent RLDLT in West China Hospital, Sichuan University from January 2005 to June 2008 were analyzed retrospectively. Among these 172 patients, 16 patients' hepatic artery flow and two patients' portal vein flow was not observed by Doppler ultrasound, and 10 patients' bridging vein flow was not shown by Doppler ultrasound and there was a regional inhomogeneous echo in the liver parenchyma upon 2D ultrasound. Thus, CEUS examination was performed in these 28 patients. RESULTS: Among the 16 patients without hepatic artery flow at Doppler ultrasound, CEUS showed nine cases of slender hepatic artery, six of hepatic arterial thrombosis that was confirmed by digital subtraction angiography and/or surgery, and one of hepatic arterial occlusion with formation of lateral branches. Among the two patients without portal vein flow at Doppler ultrasound, CEUS showed one case of hematoma compression and one of portal vein thrombosis,and both were confirmed by surgery. Among the 10 patients without bridging vein flow and with liver parenchyma inhomogeneous echo, CEUS showed regionally poor perfusion in the inhomogeneous area, two of which were confirmed by enhanced computed tomography (CT), but no more additional information about bridging vein flow was provided by enhanced CT. CONCLUSION: CEUS may be a new approach for early diagnosis of postoperative vascular complications after RLDLT, and it can be performed at the bedside.

一种新型诊断和治疗肝移植术后缺血型胆道病变模式的研究

目的寻找一种用于诊断和治疗肝移植术后缺血型胆道病变(ITBLs)的新模式。方法选取2003年10月至2012年6月在中山大学附属第三医院肝脏移植中心行原位肝移植手术后确诊为ITBLs的80例受者。其中,传统模式组37例受者在出现ITBLs症状后接受药物治疗,明确诊断后行介入治疗和手术治疗,无效者行再次肝移植。早期诊断与干预模式(EDIM)组43例受者接受预防性药物治疗,定期行胆道超声造影,出现ITBLs征象时给予人脐带间充质干细胞移植,明确诊断后行介入治疗和手术治疗,无效者行再次肝移植。采用t检验比较两组受者初诊为ITBLs的时间、采取介入治疗的时间及移植肝丢失时间,采用Kaplan-Meier曲线和Log-Rank法比较两组移植肝1,3年生存率。结果传统模式组受者和EDIM组受者术后初诊为ITBLs的平均时间分别为(56±31)d和(24±19)d,两组比较差异有统计学差异(t=5.136,P<0.05)。传统模式组和EDIM组从确诊为ITBLs到采取介入治疗的平均时间分别为(105±42)d和(58±20)d,两组比较差异有统计学差异(t=7.035,P<0.05)。传统模式组和EDIM组死亡受者分别为8例和7例。传统模式组移植肝1,3年生存率分别89.2%,54.1%,EDIM组移植肝1,3年生存率分别95.3%,81.3%,传统模式组受者移植肝1,3年生存率均低于EDIM组(χ2=4.219,P<0.05)。传统模式组和EDIM组移植肝丢失时间分别为(25±9)个月和(33±10)个月,传统模式组出现移植肝丢失时间早于EDIM组(t=-2.085,P=0.018)。结论早期诊断和干预ITBLs的新型模式可以延长术后移植肝存活时间,延迟移植肝丢失时间,提高ITBLs的整体治疗效果。