Contrast-enhanced ultrasound for the assessment of focal nodular hyperplasia - results of a multicentre study.

AIM: Contrast-enhanced ultrasound (CEUS) has become a relevant imaging method for the evaluation of focal liver le-sions (FLL). The aim of this study was to evaluate the performance of CEUS for the assessment of focal nodular hyperplasia (FNH) in a large study group. MATERIAL AND METHODS: We performed a multicentre prospective observational study, which included successive CEUS examinations from fourteen Romanian centres. CEUS examinations were performed in de novo FLL, using low mechanical index ultrasound, following an intravenous bolus of 2.4 ml SonoVue. CEUS was considered conclusive for FNH if a typical pattern was present following contrast (rapid "spoke-wheel" enhancement during the arterial phase, hyperenhanced lesion during venous phase, hyper- or isoenhanced in the late phase). In all cases a reference method was available (contrast enhanced CT or MRI or biopsy). The trial was registered in clinicaltrials.gov (Identifier NCT01329458). RESULTS: During the 6 years study, 2062 "de novo" FLL were evaluated by CEUS. From this cohort, 94/2062 (4.5%) had a typical enhancing pattern for FNH as described in the EFSUMB guidelines. Contrast enhanced CT/MRI and biopsy diagnosed additional 15 FNH. From the 94 cases diagnosed as FNH by CEUS, in nine the final diagnosis was different (five of them adenomas). CEUS had 85% sensitivity, 99.5% specificity, 90.4% positive predictive value, 99.2% negative predictive value and 98.8% diagnostic accuracy for the diagnosis of FNH. CONCLUSIONS: CEUS is a sensitive and very specific method for the diagnosis of FNH.

Advantages and Limitations of Focal Liver Lesion Assessment with Ultrasound Contrast Agents: Comments on the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines.

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography. Due to US contrast agents (UCAs) and contrast-specific techniques, sonography offers the potential to show enhancement of liver lesions in a similar way as contrast-enhanced cross-sectional imaging techniques. The real-time assessment of liver perfusion throughout the vascular phases, without any risk of nephrotoxicity, represents one of the major advantages that this technique offers. CEUS has led to a dramatic improvement in the diagnostic accuracy of US and subsequently has been included in current guidelines as an important step in the diagnostic workup of focal liver lesions (FLLs), resulting in a better patient management and cost-effective therapy. The purpose of this review was to provide a detailed description of contrast agents used in different cross-sectional imaging procedures for the study of FLLs, focusing on characteristics, indications and advantages of UCAs in clinical practice.

Diagnostic accuracy of controlled attenuation parameter measured by transient elastography for the non-invasive assessment of liver steatosis: a prospective study.

BACKGROUND AND AIMS: A novel non-invasive tool based on the evaluation of ultrasound attenuation using transient elastography (TE) has been developed, called controlled attenuation parameter (CAP). We aim to establish the histopathological parameters that significantly influence CAP, the cutoff values and their performance in predicting each steatosis grade on a group of biopsied patients with chronic liver diseases (CLD) from Romania. METHODS: We prospectively analyzed 201 consecutive CLD patients who underwent CAP measurements using TE. Steatosis, liver fibrosis and necroinflammatory activity were staged and graded during the pathological analysis of bioptic specimens. Univariate and multivariate regression analyses were applied to identify the variables correlated with CAP values. The diagnostic performance of CAP for steatosis prediction was assessed using an AUC analysis. RESULTS: Among the histopathological factors correlating with CAP, the multivariate analysis found steatosis as the only factor independently influencing CAP values (p < 0.001). Maximal diagnostic accuracy (DA) was obtained for the prediction of ≥ 34-66% (S2) fatty load and of 67-100% (S3) fatty load (82.06%, respectively 81.59%) while, for the prediction of ≥ 11-33% (S1) fatty load, DA reached only 76.11%. The negative predictive value for the exclusion of ≥ S2 and S3 was 93.5% and 98.7%, respectively. AUCs calculated between each two steatosis grades were: 0.772 (S0 vs S1), 0.874 (S0 vs S2), 0.904 (S0 vs S3), 0.659 (S1 vs S2), 0.777 (S1 vs S3), and 0.665 (S2 vs S3). CONCLUSION: Steatosis is the only histopathological factor independently influencing CAP. Maximal DA could be obtained for the prediction of ≥ S2 and S3 (82.06% and 81.59%), while for the prediction of S1, the accuracy reached only 76.11%.

Role of contrast enhanced ultrasound in the assessment of biliary duct disease.

The introduction of microbubble contrast agents (CA), which act as blood pool tracers, has overcome the limitations of conventional B-Mode, colour or power Doppler ultrasound, enabling the display of parenchymal microvasculature. Initially, the use of CA was accepted for hepatic lesions. In the following years, experts have expanded recommendations, as a result of the method's efficiency in extrahepatic applications. In this article we review the methodology and the application of contrast-enhanced ultrasound (CEUS) in the evaluation of biliary pathology. This new imaging tool allows a non invasive differential diagnosis of biliary lesions and a clearer delineation of the tumoral process.

Performance of a new elastographic method (ARFI technology) compared to unidimensional transient elastography in the noninvasive assessment of chronic hepatitis C. Preliminary results.

BACKGROUND AND AIMS: The current study aims to evaluate the performance of a new elastographic method (ARFI) in noninvasive fibrosis assessment and to compare it to another validated technology (transient elastography, TE). METHOD: 112 consecutive chronic hepatitis C patients (histologically proven according to the Metavir scoring system: 12.5% F0, 26.6% F1, 16.1% F2, 7.1% F3, 37.5% F4) were prospectively included in this study. They were examined on the same day, using both ARFI (with shear wave velocity--SWV-quantification) and TE (with liver stiffness quantification). RESULTS: SWV is correlated only with fibrosis (r=0.717, p less than 0.0001) and necroinflammatory activity (r=0.328, p=0.014), but not with steatosis (r=0.122, p=0.321). There is a significant increase of SWV in parallel with the increase in the fibrosis stage: 1.079+/-0.150 (F0-F1), 1.504+/-0.895 (F2), 1.520+/-0.575 (F3), 2.552+/-0.782 (F4), p<0.0001, but there is a certain degree of overlap between the consecutive stages F1-F2 (p=0.072), F2-F3 (p=0.965). SWV cut-off values (m/s) that were predictive for each fibrosis stage were: 1.19 (F more or equal to 1), 1.34 (F>or=2), 1.61 (F more or equal to 3) and 2.00 (F4). AUROC for ARFI vs TE were: 0.709 vs 0.902, p=0.006 (F>or=1), 0.851 vs 0.941, p=0.022 (F>or=2), 0.869 vs 0.926, p=0.153 (F>or=3) and 0.911 vs 0.945, p=0.331 (F4). CONCLUSIONS: ARFI allows SWV quantification, in strong correlation with the fibrosis stage. Steatosis does not influence SWV. The maximal performance of the method consists of the prediction in severe fibrosis and cirrhosis. The diagnostic accuracy is strongly comparable to TE only for the prediction of severe fibrosis and cirrhosis, whereas for earlier stages, TE performs better.