Contrast-enhanced ultrasound of histologically proven hepatic epithelioid hemangioendothelioma

AIM: To analyze contrast-enhanced ultrasound(CEUS) features of histologically proven hepatic epithelioid hemangioendothelioma(HEHE) in comparison to other multilocular benign focal liver lesions(FLL).METHODS: Twenty-five patients with histologically proven HEHE and 45 patients with histologically proven multilocular benign FLL were retrospectively reviewed. Four radiologists assessed the CEUS enhancement pattern in consensus.RESULTS: HEHE manifested as a single(n = 3) or multinodular(n = 22) FLL. On CEUS, HEHE showed rim-like(18/25, 72%) or heterogeneous hyperenhancement(7/25, 28%) in the arterial phase and hypoenhancement(25/25, 100%) in the portal venous and late phases(PVLP), a sign of malignancy. Eighteen patients showed central unenhanced areas(18/25, 72%); in seven patients(7/25, 28%), more lesions were detected in the PVLP. In contrast, all patients with hemangioma and focal nodular hyperplasia showed hyperenhancement as the most distinctive feature(P < 0.01).CONCLUSION: CEUS allows for characterization of unequivocal FLL. By analyzing the hypoenhancement in the PVLP, CEUS can determine the malignant nature of HEHE.

New ultrasound techniques for lymph node evaluation

Conventional ultrasound(US)is the recommended imaging method for lymph node(LN)diseases with the advantages of high resolution,real time evaluation and relative low costs.Current indications of transcutaneous ultrasound and endoscopic ultrasound include the detection and characterization of lymph nodes and the guidance for LN biopsy.Recent advances in US technology,such as contrast enhanced ultrasound(CEUS),contrast enhanced endoscopic ultrasound(CE-EUS),and real time elastography show potential to improve the accuracy of US for the differential diagnosis of benign and malignant lymph nodes.In addition,CEUS and CE-EUS have been also used for the guidance of fine needle aspiration and assessment of treatment response.Complementary to size criteria,CEUS could also be used to evaluate response of tumor angiogenesis to anti-angiogenic therapies.In this paper we review current literature regarding evaluation of lymphadenopathy by new and innovative US techniques.

Contrast-enhanced ultrasonography parameters in neural network diagnosis of liver tumors

AIM:To study the role of time-intensity curve(TIC) analysis parameters in a complex system of neural networks designed to classify liver tumors.METHODS:We prospectively included 112 patients with hepatocellular carcinoma(HCC)(n = 41),hypervascular(n = 20) and hypovascular(n = 12) liver metastases,hepatic hemangiomas(n = 16) or focal fatty changes(n = 23) who underwent contrast-enhanced ultrasonography in the Research Center of Gastroenterology and Hepatology,Craiova,Romania.We recorded full length movies of all contrast uptake phases and post-processed them offline by selecting two areas of interest(one for the tumor and one for the healthy surrounding parenchyma) and consecutive TIC analysis.The difference in maximum intensities,the time to reaching them and the aspect of the late/portal phase,as quantified by the neural network and a ratio between median intensities of the central and peripheral areas were analyzed by a feed forward back propagation multi-layer neural network which was trained to classify data into five distinct classes,corresponding to each type of liver lesion.RESULTS:The neural network had 94.45% training accuracy(95% CI:89.31%-97.21%) and 87.12% testing accuracy(95% CI:86.83%-93.17%).The automatic classification process registered 93.2% sensitivity,89.7% specificity,94.42% positive predictive value and 87.57% negative predictive value.The artificial neural networks(ANN) incorrectly classified as hemangyomas three HCC cases and two hypervascular metastases,while in turn misclassifying four liver hemangyomas as HCC(one case) and hypervascular metastases(three cases).Comparatively,human interpretation of TICs showed 94.1% sensitivity,90.7% specificity,95.11% positive predictive value and 88.89% negative predictive value.The accuracy and specificity of the ANN diagnosis system was similar to that of human interpretation of the TICs(P = 0.225 and P = 0.451,respectively).Hepatocellular carcinoma cases showed contrast uptake during the arterial phase followed by wash-out in the portal and first seconds of the late phases.For the hypovascular metastases did not show significant contrast uptake during the arterial phase,which resulted in negative differences between the maximum intensities.We registered wash-out in the late phase for most of the hypervascular metastases.Liver hemangiomas had contrast uptake in the arterial phase without agent wash-out in the portallate phases.The focal fatty changes did not show any differences from surrounding liver parenchyma,resulting in similar TIC patterns and extracted parameters.CONCLUSION:Neural network analysis of contrastenhanced ultrasonography-obtained TICs seems a promising field of development for future techniques,providing fast and reliable diagnostic aid for the clinician.

Hybrid ultrasound imaging techniques(fusion imaging)

Visualization of tumor angiogenesis can facilitate noninvasive evaluation of tumor vascular characteristics to supplement the conventional diagnostic imaging goals of depicting tumor location,size,and morphology.Hybrid imaging techniques combine anatomic [ultrasound,computed tomography(CT),and/or magnetic resonance imaging(MRI)] and molecular(single photon emission CT and positron emission tomography) imaging modalities.One example is real-time virtual sonography,which combines ultrasound(grayscale,colour Doppler,or dynamic contrast harmonic imaging) with contrast-enhanced CT/MRI.The benefits of fusion imaging include an increased diagnostic confidence,direct comparison of the lesions using different imaging modalities,more precise monitoring of interventional procedures,and reduced radiation exposure.

Molecular confocal laser endomicroscopy:A novel technique for in vivo cellular characterization of gastrointestinal lesions

While flexible endoscopy is essential for macroscopic evaluation,confocal laser endomicroscopy(CLE)has recently emerged as an endoscopic method enabling visualization at a cellular level.Two systems are currently available,one based on miniprobes that can be inserted via a conventional endoscope or via a needle guided by endoscopic ultrasound.The second system has a confocal microscope integrated into the distal part of an endoscope.By adding molecular probes like fluorescein conjugated antibodies or fluorescent peptides to this procedure(either topically or systemically administered during on-going endoscopy),a novel world of molecular evaluation opens up.The method of molecular CLE could potentially be used for estimating the expression of important receptors in carcinomas,subsequently resulting in immediate individualization of treatment regimens,but also for improving the diagnostic accuracy of endoscopic procedures by identifying otherwise invisible mucosal lesions.Furthermore,studies have shown that fluorescein labelled drugs can be used to estimate the affinity of the drug to a target organ,which probably can be correlated to the efficacy of the drug.However,several of the studies in this research field have been conducted in animal facilities or in vitro,while only a limited number of trials have actually been carried out in vivo.Therefore,safety issues still needs further evaluations.This review will present an overview of the implications and pitfalls,as well as future challenges of molecular CLE in gastrointestinal diseases.

Current role of non-anesthesiologist administered propofol sedation in advanced interventional endoscopy

Complex and lengthy endoscopic examinations like endoscopic ultrasonography and/or endoscopic retrograde cholangiopancreatography benefit from deep sedation, due to an enhanced quality of examinations, reduced discomfort and anxiety of patients, as well as increased satisfaction for both the patients and medical personnel. Current guidelines support the use of propofol sedation, which has the same rate of adverse effects as traditional sedation with benzodiazepines and/or opioids, but decreases the procedural and recovery time. Non-anesthesiologist administered propofol sedation has become an option in most of the countries, due to limited anesthesiology resources and the increasing evidence from prospective studies and metaanalyses that the procedure is safe with a similar rate of adverse events with traditional sedation. The advantages include a high quality of endoscopic examination, improved satisfaction for patients and doctors, as well as decreased recovery and discharge time. Despite the advantages of non-anesthesiologist administered propofol, there is still a continuous debate related to the successful generalization of the procedures.

Current strategies for malignant pedunculated colorectal polyps

Despite significant advances in imaging techniques, the incidence of colorectal cancer has been increasing in recent years, with many cases still being diagnosed in advanced stages. Early detection and accurate staging remain the main factors that lead to a decrease in the cost and invasiveness of the curative techniques, significantly improving the outcome. However, the diagnosis of pedunculated early colorectal malignancy remains a current challenge. Data on the management of pedunculated cancer precursors, apart from data on nonpolypoid lesions, are still limited. An adequate technique for complete resection, which provides the best long-term outcome, is mandatory for curative intent. In this context, a discussion regarding the diagnosis of malignancy of pedunculated polyps, separate from nonpedunculated variants, is necessary. The purpose of this review is to provide a critical review of the most recent literature reporting the different features of malignant pedunculated colorectal polyps, including diagnosis and management strategies.

Tumor neoangiogenesis detection by confocal laser endomicroscopy and anti-CD105 antibody:Pilot study

AIM: To evaluate neoangiogenesis in patients with colon cancer by two fluorescently labeled antibodies on fresh biopsy samples imaged with confocal laser endomicroscopy(CLE).METHODS: CLE is an imaging technique for gastrointestinal endoscopy providing in vivo microscopy at subcellular resolution.An important question in validating tumor angiogenesis is what proportion of the tumor vascular network is represented by preexisting parent tissue vessels and newly formed vessels.CD105(endoglin) represents a proliferation-associated endothelial cell adhesion molecule.In contrast to panendothelial markers,such as CD31,CD105 is preferentially expressed in activated endothelial cells that participate in neovascularization.Thus,we evaluated CD105 and CD31 expression from samples of ten patients with primary rectal adenocarcinoma,using a dedicated endomicroscopy system.A imaging software was used to obtain the Z projection of the confocal serial images from each biopsy sample previously combined into stacks.Vascular density and vessel diameters were measured within two 50 μm x 475 μm rectangular regions of interest centered in the middle of each image in the horizontal and vertical direction.The results were averaged over all the patients and were expressed as the mean ± SE.RESULTS: The use of an anti-CD105 antibody was found to be suitable for the detection of blood vessels in colon cancer.Whereas anti-CD31 antibodies stained blood vessels in both normal and pathologic colon equally,CD105 expression was observed primarily in malignant lesions,with little or no expression in the vessels of the normal mucosa(244.21 ± 130.7 vessels/mm3 in only four patients).The average diameter of antiCD105 stained vessels was 10.97 ± 0.6 μm in tumor tissue,and the vessel density was 2787.40 ± 134.8 vessels/mm3.When using the anti-CD31 antibody,the average diameter of vessels in the normal colon tissue was 7.67 ± 0.5 μm and the vessel density was 3191.60 ± 387.8 vessels/mm3,while in the tumors we obtained an average diameter of 10.88 ± 0.8 μm and a vessel density of 4707.30 ± 448.85 vessels/mm3.Thus,there were more vessels stained with CD31 than CD105(P < 0.05).The average vessel diameter was similar for both CD31 and CD105 staining.A qualitative comparison between CLE vs immunohistochemistry lead to similar results.CONCLUSION: Specific imaging and quantification of tumor microvessels are feasible in human rectal cancer using CLE examination and CD105 immunostaining of fresh tissue samples.