Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.     

Diagnosis of liver cirrhosis with contrast-enhanced ultrasound

The assessment of the extent of liver fibrosis is very important for the prognosis and clinical management of chronic liver diseases. Although liver biopsy is the gold standard for the assessment of liver fibrosis, new non-invasive diagnostic methods are urgently needed in clinical work due to certain limitations and complications of biopsy. Noninvasive imaging studies play an important role in the diagnosis of focal liver disease and diffuse liver diseases. Among them, ultrasonography is the first choice for study of the liver in clinical work. With the development of ultrasound contrast agents and contrast specific imaging techniques, contrast-enhanced ultrasound (CEUS) shows good performance and great potential in the evaluation of liver fibrosis. Researchers have tried different kinds of contrast agent and imaging method, such as arrival time of contrast agent in the hepatic vein, and quantitative analysis of the enhancement level of liver parenchyma, to evaluate the degree of liver fibrosis during the past 10 years. This review mainly summarizes the clinical studies concerning the assessment of liver fibrosis using CEUS.     

Magnetic resonance imaging in chronic liver disease evaluated in relation to hepatic fibrosis--clinical and experimental results

In 21 patients with chronic liver disease, the ratio of liver to muscle signal intensity on T1-weighted images was negatively correlated with the progression of hepatic fibrosis defined according to findings by laparoscopy and liver biopsy, and differentiated six patients with early chronic hepatitis from eight with liver cirrhosis. On T2-weighted images, the number of low intensity nodules comparable in size to regenerating nodules surrounded by connective tissues showed a positive correlation with stage. When hepatic fibrosis with no necrosis or fat infiltration was induced in rats, T2 values were positively correlated with hepatic hydroxyproline content, though there was no such correlation for T1 values. These results suggest that MR imaging may be useful for determining the progression of hepatic fibrosis in chronic liver disease. T2 values may directly reflect hepatic fibrosis.     

脂肪肝对超声诊断肝纤维化的影响

目的：探讨不同程度脂肪肝对超声诊断肝纤维化的影响。方法回顾性分析我院363例肝病患者,均经肝穿刺活检确诊为肝纤维化,病理分期为S1-S4四期,其中脂肪肝患者223例,无脂肪肝患者140例,按纤维化分期及脂肪肝分度,分别观察肝脏实质回声的改变,采用秩和检验的统计学方法,分析不同程度脂肪肝对肝纤维化超声诊断结果的影响。结果轻度脂肪肝对各程度肝纤维化超声诊断结果的影响差异无统计学意义（P〉0.05）,中、重度脂肪肝使诊断的准确率下降,中度脂肪肝与无脂肪肝组比较,在S1-S2期差异有统计学意义（P〈0.05）,重度脂肪肝与无脂肪肝组比较,在S1-S3期差异有统计学意义（P〈0.05）,S4期的诊断受肝细胞脂肪变性的影响较小,差异无统计学意义（P〉0.05）。结论不同程度脂肪肝对超声诊断肝纤维化存在影响,并可能使诊断结果偏轻于病理结果。     

彩色多普勒超声在原位肝移植术后黄疸鉴别诊断中的价值

目的:探讨彩色多普勒超声(CDFI)在原位肝移植术后黄疸鉴别诊断中的应用价值。方法:使用彩色多昔勒超声观察18例原位肝移植术后发生黄疸患者的肝脏动静脉血流变化及胆管、肝实质声像图改变,主要观察指标有最大血流速度、时间平均血流速度(TAV)、阻力指数(RI)及胆管内径,并结合临床资料、肝穿刺活检病理结果和内镜逆行胰胆管造影(ERCP)表现等进行综合分析。结果:18例患者于术后6天-5个月发生黄疸,持续时间为12天-1年。其中13例为胆道并发症,5例为胆总管吻合口狭窄,2例为慢性胆管炎,2例为肝内胆管结石,1例为左肝管胆泥形成并霉菌感染,3 例为肝内胆管轻度扩张,其余5例经肝穿刺活检证实为轻度急性排斥反应4例、临界急性排斥反应1例。结论:彩色多普勒超声成像技术对原位肝移植术后黄疸具有重要的鉴别诊断价值,对临床医生判断病情有重要意义。     

Case report: unusual CT appearances in a case of Budd-Chiari syndrome

We describe a case of Budd-Chiari Syndrome due to hepatic venous blockage in which there were multiple space-occupying lesions on CT simulating tumour deposits. Ultrasound directed liver biopsy and laparoscopy proved these to be areas of haemorrhagic necrosis consistent with Budd-Chiari Syndrome without any evidence of malignancy. The CT finding of multiple large focal non-enhancing areas in liver does not always indicate tumour deposits in a patient suspected to have Budd-Chiari Syndrome.     

Hepatic angiography in ulcerative colitis and Crohn's disease.

Liver angiography was performed in 13 patients with Crohn's disease and three with ulcerative colitis. Of these patients, 13 underwent liver biopsy, and findings were correlated with results of angiography and biochemical tests. Twelve liver biopsies were abnormal, primarily showing fatty infiltration and reactive hepatitis. Thirteen angiographies were abnormal, with widened and tortuous liver arteries being the most common finding. Liver function tests were within normal limits for all but three of the 16 patients, thus correlating poorly with findings of the other tests. These data show that angiography is useful in detecting hepatic abnormality, but evaluation with liver biopsy is necessary to determine the nature of the lesion.     

Ultraschallgestützte Bildfusion mittels CT und MRT

Abdominal ultrasound is often the first-line imaging modality for assessing focal liver lesions. Due to various new ultrasound techniques, such as image fusion, global positioning system (GPS) tracking and needle tracking guided biopsy, abdominal ultrasound now has great potential regarding detection, characterization and treatment of focal liver lesions. Furthermore, these new techniques will help to improve the clinical management of patients before and during interventional procedures. This article presents the principle and clinical impact of recently developed techniques in the field of ultrasound, e.g. image fusion, GPS tracking and needle tracking guided biopsy and discusses the results based on a feasibility study on 20?patients with focal hepatic lesions.     

Hepatic iron concentration: noninvasive estimation by means of MR imaging techniques.

PURPOSE: To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy. MATERIALS AND METHODS: Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentration and hepatic MR imaging with several spin-echo and gradient-recalled-echo (GRE) techniques. Correlations between MR imaging parameters and the hepatic iron concentration were determined. RESULTS: Inverse curvilinear relationships were noted between several MR parameters and hepatic iron concentrations. GRE sequences with short repetition and echo times were more accurate and precise than spin-echo sequences for the estimation of hepatic iron concentration. A GRE sequence with a repetition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degrees showed close correlation between the hepatic iron concentration and the natural logarithm of the ratio of the signal intensity of liver to the SD of background noise (r = -0.94) and low coefficient of variation (12%). CONCLUSION: MR imaging with these parameters is a rapid, noninvasive, and accurate modality for estimation of hepatic iron concentration; it is sufficiently accurate and precise to obviate liver biopsy for the purpose of measuring hepatic iron concentration.     

Diagnosis of liver cirrhosis by transit-time analysis at contrast-enhanced ultrasonography

Purpose

The aims of this prospective study were to evaluate analysis of sulfur-hexafluoride-filled microbubble contrast agent (Sonovue) transit times as a tool for differentiating liver cirrhosis from the noncirrhotic stage of liver disease and to compare its performance with that of conventional B-mode and Doppler ultrasonography (US).

Materials and methods

Contrast-enhanced hepatic ultrasonography with the US contrast agent Sonovue was performed on 38 patients with diagnoses of hepatic cirrhosis based on unequivocal clinical signs or liver biopsy findings (Child-Pugh classes A in 19, B in 16 and C in three), 31 patients with noncirrhotic diffuse liver disease (biopsy confirmed) and 14 controls without diffuse liver disease. Time curves of hepatic-vein signal intensity were analysed using objective criteria to determine the time of enhancement onset (hepatic-vein arrival time) and peak enhancement (hepatic-vein peak enhancement). Accuracy in diagnosing cirrhosis was compared with that based on B-mode and Doppler data.

Results

Hepatic-vein arrival time in cirrhotic patients was significantly shorter (p<0.01) than in noncirrhotic (chronic liver disease and controls) patients. Peak enhancement times in these three groups were not significantly different. An arrival-time cutoff of 17 s distinguished cirrhotic from noncirrhotic patients with high accuracy (100% sensitivity, 93.3% specificity, positive and negative predictive values 92.6% and 100%, respectively) and excellent reproducibility (kappa coefficients of 1.0 and 0.93 for intraand interobserver agreement). Contrast-enhanced US showed better sensitivity than the B-mode and Doppler data.

Conclusions

Analysis of the time of onset of US contrast enhancement of the hepatic vein appears to be a potentially useful noninvasive supplement to conventional sonography and Doppler in the follow-up of patients with chronic diffuse liver disease.     

Ultrasonography as a non-invasive tool for detection of nonalcoholic fatty liver disease in overweight/obese Egyptian children

Introduction

Liver biopsy, although a gold standard in diagnosis of nonalcoholic fatty liver disease (NAFLD), is an invasive and expensive tool.

Aim

To assess the diagnostic accuracy of abdominal ultrasound in detecting NAFLD among a group of overweight/obese children having one or more liver abnormality (clinical hepatomegaly, raised ALT or echogenic liver parenchyma by ultrasound).

Methods

Seventy-eight overweight/obese children were referred to the Pediatric Hepatology Unit, Cairo University Pediatric Hospital, Egypt, for assessment for hepatic abnormalities. Out of the 78 children, 34 had one or more abnormality in the form of clinical hepatomegaly, raised alanine aminotransferase (ALT) and/or echogenic liver parenchyma by ultrasound. All 34 cases underwent liver biopsy for evaluation for NAFLD.

Results

Histological NAFLD was detected in 15 cases; 8 simple steatosis and 7 nonalcoholic steatohepatitis (NASH). Sonographic evaluation of hepatic parenchymal echogenicity revealed: 11 with grade 1 echogenicity, 12 with grade 2 and 9 with grade 3 while only 2 had normal liver echopattern. Ultrasonography was 100% sensitive and 100% specific in detecting histological NAFLD, while the positive predictive value (PPV) was 47% and negative predictive value (NPV) was 11%. After consolidating the included children into 2 groups: the first including normal and grade 1 echogenicity and the second including grades 2 and 3, the sensitivity of ultrasonography in detecting histological NAFLD was still 100%, while negative predictive value increased to 100% with an accuracy of 82%.

Conclusion

We conclude that ultrasonography is an important non invasive tool in assessment for NAFLD. Normal or grade 1 hepatic echogenicity can soundly exclude histological NAFLD and obviates the need for liver biopsy.     

肝移植术后急性肝动脉血栓形成的介入治疗

目的评价用血管内介入放射学技术治疗原位肝移植后急性肝动脉血栓形成(HAT)的安全性和疗效。方法对10例肝移植后早期发生急性HAT患者进行了介入治疗。10例均表现为术后转氨酶、胆红素进行性增高。HAT发生于移植术后16h～10d(平均4.5d),Doppler超声波检查提示HAT,经血管造影证实。血管内介入技术有肝动脉内留置导管持续低剂量溶栓和肝动脉内支架置入术,同时经静脉给予低剂量肝素。肝动脉内溶栓期间间隔6～12h复查超声波。结果10例均表现为肝固有动脉完全阻塞。溶栓治疗成功8例。复查血管造影显示肝固有动脉有血流通过,肝内动脉分支显影,肝功能明显改善。肝动脉内留置导管时间为12h～9d(平均4.8d)。8例溶栓成功的患者均存在肝固有动脉吻合口处狭窄,其中7例狭窄程度>90%,进行肝动脉血管内支架置入术。溶栓治疗失败2例,1例于溶栓开始后12h发生腹腔内出血,行急诊开腹探查,发现肝动脉吻合口出血,随即再次吻合;1例留置导管溶栓7d后未能开通肝动脉阻塞,但向肝脏供血的侧支建立、肝功能有所改善,未作进一步治疗。8例治疗成功者术后随访4～20个月(中位值12个月),一般情况良好,复查超声波显示肝动脉血流通畅。结论血管内介入放射学技术是治疗肝移植后早期急性HAT的有效方法,有较高的安全性。     

超声造影评估经皮射频凝固治疗闭合性肝外伤的实验研究

目的 探讨超声造影评估经皮射频凝固治疗闭合性肝外伤的价值.方法 建立16只猪闭合性肝外伤伴活动性出血模型,随机分为治疗组和对照组,每组各8只.对治疗组进行超声造影引导下经皮射频凝固治疗,对照组不进行治疗.将检查结果与相关的病理结果进行对照研究.结果 射频凝固治疗前,治疗组和对照组超声造影均可见肝活动性出血信号.第1次射频凝固治疗后,治疗组7例动物超声造影未见肝活动性出血信号,另1例仍可见肝活动性出血信号.经第2次射频凝固治疗后,超声造影未见肝活动性出血信号.治疗后1小时,治疗组超声造影未见肝活动性出血.撞击后1小时,对照组仍可见肝活动性出血.超声造影结果与病理结果相关性好.结论 超声造影是一种可靠的实时评估射频凝固治疗闭合性肝外伤疗效的方法.     

US approach to jaundice in infants and children.

High-resolution real-time ultrasonography (US) serves as an important tool for differentiation of obstructive and nonobstructive causes of jaundice in infants and children, independent of liver function. Unconjugated hyperbilirubinemia occurs in approximately 60% of normal term infants and in 80% of preterm infants. Persistence of neonatal jaundice beyond 2 weeks of age demands US evaluation to differentiate between the three most common causes: hepatitis, biliary atresia, and choledochal cyst. In all three conditions, the hepatic echotexture is diffusely coarse and hyperechoic, but this appearance may be seen in a variety of hepatic inflammatory, obstructive, and metabolic processes. Thus, hepatic scintigraphy and at times percutaneous liver biopsy are necessary to narrow the differential diagnosis and to identify patients who require more invasive techniques (eg, intraoperative cholangiography). US is useful for demonstrating inspissated bile and biliary duct stones. In infants, stones are usually secondary to obstructive congenital anomalies of the biliary tract, total parenteral nutrition, furosemide treatment, phototherapy, dehydration, infection, hemolytic anemia, and short-gut syndrome, whereas in older children, stones are usually associated with sickle cell disease, bowel resection, hemolytic anemia, and choledochal cyst. Jaundice in infants and children may also be due to cirrhosis, benign strictures, and neoplastic processes.     

Spontaneous intrahepatic hemorrhage: a severe complication of the Hellp syndrome. Value of early radiologic diagnosis. Apropos of a case

One case of spontaneous hepatic hemorrhage during a severe pre-eclampsia and Hellp syndrome (hemolysis, elevated liver function tests, low platelet count) is reported. This serious complication can be detected by ultrasonography and C.T. The normal sonographic appearance of the liver must prompt a new sonographic examination as soon as possible. C.T. of the abdomen confirmes the diagnosis and delineates the lesions more precisely. It is suggested that with the availability of ultrasound and computed tomography to diagnose and stage the hepatic hemorrhage, they have a systematic indication during the Hellp syndrome.     

Hepatobiliary Intervention in Children

Various vascular and nonvascular hepatobiliary interventional radiology techniques are now commonly performed in children’s hospitals. Although the procedures are broadly similar to interventional practice in adults, there are important differences in indications and technical aspects. This review describes the indications, techniques, and results of liver biopsy, hepatic and portal venous interventions and biliary interventions in children.     

Ultrasonographic detection of hepatocellular carcinoma: correlation of preoperative ultrasonography and resected liver pathology

AIM: The aim of this study was to determine the sensitivity of ultrasonography for detecting hepatocellular carcinoma in patients who underwent surgical liver resection. MATERIALS AND METHODS: The preoperative ultrasonography reports of 103 patients who underwent hepatic resection surgery were retrospectively reviewed. The patients had chronic liver disease with good liver function and a relatively normal liver echo-texture. The presence of a mass or masses in the resected part of the liver segments on preoperative ultrasonography was regarded as possible hepatocellular carcinoma, and these results were compared with the surgically resected hepatic lobes or segments. Accuracy for detection was assessed on a lesion-by-lesion basis, on a segment-by-segment basis, and on a patient basis. RESULTS: One hundred and fifty-seven hepatocellular carcinomas were found in 244 hepatic segments of 103 patients. One hundred and one of 157 hepatocellular carcinomas were detected using ultrasonography in 97 patients resulting in a sensitivity of 64%. In six patients, a solitary hepatocellular carcinoma was missed in each patient, a patient sensitivity being 94%. Using ultrasonography, 87 of 100 (87%) hepatocellular carcinomas larger than 2 cm in diameter, and 14 of 57 (25%) hepatocellular carcinomas 2 cm or smaller in diameter were revealed. On the basis of segment-by-segment analysis, the sensitivity was 78% (99 of 127 segments), specificity was 97% (114 of 117 segments), accuracy was 87% (213 of 244 segments), positive predictive value was 97% (99 of 102 segments), and negative predictive value was 80% (114 of 142 segments). CONCLUSION: In patients with chronic liver disease and good hepatic function, ultrasonography has a sensitivity of 94% in the identification of affected patients, but for individual lesions, the sensitivity is only 64%.     

超声诊断非典型肝血管瘤的临床应用价值

目的　探讨超声诊断非典型肝血管瘤的临床应用价值。方法　对 3 6例经CT检查、MRI、超声引导下经皮肝穿刺活检和 (或 )手术病理证实的非典型肝血管瘤的超声及临床资料进行回顾性分析。结果　 2DE +CDFI检查 2 9例 ,超声诊断符合率 83 % ( 2 4/ 2 9) ,单用 2DE检查 7例 ,超声诊断符合率仅 43 % ( 3 / 7)。结论　超声是肝血管瘤检查的首选方法 ,CDFI对非典型肝血管瘤能作出较准确的诊断     

Diagnostic value of transverse axial tomoscintigraphy for the detection of hepatic metastases: Results on 53 examinations and comparison with other diagnostic techniques

We present the results obtained from 53 hepatic tomoscintigrams (48 patients) that principally correspond to primary gastrointestinal cancers with possible hepatic metastases. We have tested this technique and extracted the most significant images from this relatively small number of patients.We have also developed a new diagnostic evaluation technique to compare tomoscintigraphy with other techniques: surgery, echography, scintigraphy, biological hepatic tests (GOT, GPT, G-GT, alkaline phosphatase), and carcinoembryonic antigen (CEA). According to our results, hepatic tomoscintigraphy is among the most efficient diagnostic techniques for the detection of hepatic metastases: it is at least equivalent to surgery and superior to the other techniques studied.This work was supported by Clinical Research Grant 80 A4 from the Institut Gustave-Roussy     

胆囊结石合并肝癌、肝硬化患者腹腔镜保胆取石术一例报告

目的探讨针对胆囊结石合并肝硬化、肝癌患者施行腹腔镜保胆取石术的适应证和手术方法。方法 1例胆囊结石合并肝硬化、肝癌患者在全麻下采用腹腔镜胆囊切除术(LC)的标准四戳孔,借助胆道镜、取石网处理胆囊结石,胆囊壁切口用3-0可吸收缝针线"8"字扣锁缝合,取出的胆囊结石装入标本袋从脐部穿刺孔取出。Winslow孔附近常规放置1根多孔腹腔引流管观察渗漏情况。结果施行保胆取石术1例成功。术后第1天腹腔引流管引流出淡红色渗出液120 ml,随后逐日减少,颜色逐渐变为淡黄色,术后7 d拔除腹腔引流管。手术历时(穿刺Trocar到取出标本袋)130 min,术后10 d出院。无任何手术并发症发生。患者手术后次日即能正常进食。结论胆囊结石合并肝硬化、肝癌的患者,如果胆囊炎反复发作,严重影响生活,并且肝硬化、肝癌经治疗处于稳定期,无明显腹水,凝血功能尚可,胆囊存在收缩功能,就能够比较安全地施行腹腔镜保胆取石术。术后可显著改善患者生活质量。