A. Ignee

Real-time tissue elastography in the diagnosis of autoimmune pancreatitis.

Endoscopic ultrasound (EUS) elastography distinguishes tissues on the basis of their specific consistency. The preoperative diagnosis of autoimmune pancreatitis (AIP) is of the utmost importance in order to avoid surgery. The aim of this prospective evaluation of five patients was to investigate the role of this new technique in the characterization of mass lesions caused by AIP, with histology as the gold standard. All five patients with AIP presented with a characteristic stiff elastographic pattern not only of the mass lesion but also of the surrounding pancreatic parenchyma, which was not found in 17 patients with ductal adenocarcinoma and 10 healthy subjects. EUS elastography of the pancreas shows a typical and unique finding with homogenous stiffness of the whole organ, and this distinguishes AIP from the circumscribed mass lesion in ductal adenocarcinoma.

Improved characterisation of solitary solid pancreatic tumours using contrast enhanced transabdominal ultrasound

BackgroundContrast enhanced ultrasound (CEUS) is a new imaging method for detection and characterisation of liver tumours. The role of CEUS in pancreatic disease is less obvious. We prospectively evaluated CEUS for characterization of undetermined solid pancreatic lesions (gold standard histology).Patients and methodsA total of 112 solitary undetermined pancreatic masses (70 ductal adenocarcinoma and 42 neoplastic nodules of other origin) were prospectively examined in patients without metastatic disease using transabdominal ultrasound. Tumour enhancing features were analyzed in comparison to the surrounding pancreatic parenchyma in patients with adequate visualisation.ResultsThe sign of iso-hypervascularity as a sign of non-ductal adenocarcinoma showed a sensitivity of 100%, specifity of 90% and accuracy of 93.8%. The sign of hypovascularity as a sign of ductal adenocarcinoma showed a sensitivity of 90%, specifity of 100% and an accuracy of 93.8%.ConclusionCEUS allows differential diagnosis of ductal adenocarcinoma and non-ductal adenocarcinoma (mainly neuroendocrine tumours and (microcystic) serous pancreatic adenoma) in the most of cases.

Pitfalls and Artefacts using Contrast Enhanced Ultrasound

Ultrasound is the method of choice in the detection and characterization of diffuse and focal organic diseases. For B-mode and colour (power) Doppler ultrasound, besides manual skills, (hands-on) a technical knowledge about ultrasound images is of the upmost importance for the investigator. Contrast enhanced ultrasound (CEUS) has become an important diagnostic tool for hepatic, renal, pancreatic indications and several others due to: (a) an increasing rate of studies resulting in sufficient evidence especially in hepatic indications, (b) a rate of adverse events close to zero (1:10,000 in comparison to iodinated contrast agents from 1-12:100) enabling the application of CEUS in patients with severe renal insufficiency or thyroid gland autonomy, and (c) a reasonable price (depends on the country and influence of the health-care system [reimbursement]) and the dosage used. Mini-doses from 0.1 to 0.4 mL are used depending on the contrast agent and applied indication. Therefore a well founded knowledge concerning the technical aspects of CEUS is important for the investigator to avoid misinterpretation especially when artefacts specific for CEUS occur. Special literature is rare. In the presented article we present pitfalls concerning CEUS. The following aspects are considered and illustrated by images: (i) acoustic power (mechanical index) and other aspects resulting in micro bubble destruction, (ii) the possibility of false positive contrast signals in non-vascularized areas, (iii) attenuation caused by too high contrast agent dose, (iv) influence of the frame rate on the spatial resolution, (v) dealing with deep located lesions, (vi) differences in focus positioning in detection and characterization studies, (vii) advantages and disadvantages of replenishment studies, (viii) reliability of contrast enhanced spectral Doppler measurements.

Contrast-enhanced endoscopic ultrasound in the diagnosis of autoimmune pancreatitis.

Autoimmune pancreatitis is a rare condition which can mimic pancreatic carcinoma. We report the cases of 10 patients with autoimmune pancreatitis investigated in two different centers using contrast-enhanced endosonography. In these patients, contrast-enhanced endosonography showed a unique vascularization pattern which makes it easy to discriminate between autoimmune pancreatitis and lesions caused by pancreatic cancer. Lesions caused by autoimmune pancreatitis and the surrounding pancreas typically showed hypervascularization, whereas lesions caused by pancreatic cancer were hypovascularized. This was true for all patients with the exception of one who showed a normal vascularization pattern in comparison with normal patients and no signs of hypovascularization. Final diagnosis was achieved either by transcutaneous biopsy or a combination of endoscopic fine-needle aspiration with IgG4 immunostaining of the sample. All patients were followed up over a period of at least 12 months to rule out pancreatic carcinoma.

Contrast-enhanced ultrasound for imaging of adrenal masses.

PURPOSE The number of incidentally discovered adrenal masses is growing due to the increased use of modern high-resolution imaging techniques. However, the characterization and differentiation of benign and malignant adrenal lesions is challenging. This study aimed to evaluate contrast-enhanced ultrasound for the characterization of adrenal masses. MATERIALS AND METHODS We studied 58 patients with adrenal masses detected with computed tomography, magnetic resonance imaging, or ultrasound. 7 patients had bilateral adrenal lesions. Contrast-enhanced ultrasound was performed using high-resolution ultrasound (3.5 - 7 MHz) and intravenous injection of 2.4 ml SonoVue. The contrast enhancement pattern of all adrenal lesions was documented. RESULTS The 18 malignant adrenal tumors were significantly larger at the time of diagnosis compared to the 40 benign lesions (p < 0.03). The majority of benign adrenal lesions (37 / 40) had a nonspecific type of contrast enhancement (24 / 40) or a peripheral to central contrast filling (13 / 40) described as the iris phenomenon. Similar findings were observed in malignant adrenal tumors: most malignant lesions also showed nonspecific (6 / 18) or peripheral to central contrast filling (9 / 18). Peripheral to central contrast filling had 50 % sensitivity (26 - 74 %) and 68 % specificity (51 - 81 %) for indicating malignancy. CONCLUSION Contrast-enhanced ultrasound facilitates the visualization of vascularization even in small adrenal masses, but it does not help to distinguish malignant and benign lesions.

Contrast-Enhanced Ultrasound (CEUS) in the Diagnostic Algorithm of Hepatocellular and Cholangiocellular Carcinoma, Comments on the AASLD Guidelines

Contrast-enhanced ultrasound (CEUS) has long been present in important guidelines and recommendations for the diagnostic work-up of focal liver lesions in patients with cirrhosis. These guidelines have included the guidelines of the American Association for the Study of Liver Diseases (AASLD) 2005, the Asian Pacific Association for the Study of the Liver consensus recommendations on hepatocellular carcinoma, the recommendations of the Japanese Society of Hepatology, and the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines 2004, 2008 and 2012 (in preparation). Recently, the AASLD removed CEUS from their guidelines in part because of the perceived possibility of false-positive hepatocellular carcinoma (HCC) diagnosis in patients with intrahepatic cholangiocarcinoma (ICC), and in part because CEUS is not available in the USA. This latter factor means that published results are not entirely applicable to a North American population. The present manuscript discusses the diagnostic algorithm of hepatocellular carcinoma and provides information on the differential diagnosis between HCC and ICC.

Contrast-enhanced ultrasound-guided percutaneous cholangiography and cholangiodrainage (CEUS-PTCD)

We present our experience with contrast-enhanced ultrasound-guided percutaneous transhepatic cholangiodrainage in eight patients with obstructive jaundice and failure of conventional endoscopic retrograde cholangiography. The intraductal application of the ultrasound contrast agent led to sufficient cholangiography in all patients. In one patient, after accidental dislocation of the bile duct drain, the leakage could be detected by demonstration of the passage of contrast agent into the perihepatic peritoneal space. Further studies are necessary to evaluate this new technique in a larger numbers of patients.

EFSUMB Guidelines 2011: Comments and Illustrations

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) introduced the first guidelines on the use of contrast-enhanced ultrasound (CEUS) in 2004. This EFSUMB document focused mainly on liver applications. However, new applications extending beyond the liver were subsequently developed. Therefore, in the update of the clinical recommendations on the use of CEUS by the EFSUMB, applications in other organs were also described and published in 2008. Increased interest in recent years in the CEUS technique and in the application of CEUS in novel fields has resulted in CEUS indications and applications for nearly all organ systems. As a result, the EFSUMB initiated a new update of the guidelines in 2011 to include this additional knowledge. Some of the indications are established, whereas others are preliminary. The latter indications are categorized as emergent CEUS applications since the available evidence is insufficient for general recommendation. This article focuses on comments, illustrations and examples of the application of CEUS in the pancreas, spleen, gastrointestinal tract, kidney, adrenals, lymph nodes, perineum, and hepatobiliary system. The potential for endoscopic ultrasound to highlight the importance of CEUS in the daily routine is also addressed.

Artifacts and pitfalls in contrast-enhanced ultrasound of the liver.

Ultrasound technology is always connected to possible artefacts. Since introduction of ultrasound technology the knowledge of those artefacts is eminent to avoid misinterpretations. It is important to know that with the introduction of new ultrasound technology the possibility of artefacts are rising.Whereas artefacts initially were limited to B-mode sonography, every technological step (colour Doppler sonography, contrast enhanced sonography) comes with a range of new artefacts. This article is written to explain the technological basics of ultrasound artefacts and provide the reader with examples in daily practice and how to avoid them.

Imaging of gastrointestinal stromal tumours with modern ultrasound techniques - a pictorial essay.

Gastrointestinal stromal tumours (GIST) are rare tumours of the gastrointestinal tract. Dealing with these tumours requires a profound knowledge of the nature of the lesions and their malignant potentials. Modern ultrasound techniques provide the necessary tools to give the clinician the information he needs to diagnose and treat the patient. This article reviews the actual pathophysiological knowledge of GIST and provides a broad spectrum of ultrasound findings to introduce the reader into modern ultrasound investigation methods of subepithelial tumours. It covers the transcutaneous as well as the endoscopic ultrasound approach. Different conditions of GIST like the low risk or high risk form as well as the metastatic form will be discussed in diagnosis and treatment with plenty of examples. Special attention is paid to contrast-enhanced ultrasound techniques and elastography from the transcutaneous as well as the endoscopic route. Other diagnostic methods like CT, MRI and PET CT are additionally reviewed and their role in clinical practice is compared with that of ultrasound. The aim of the article is to introduce the reader into the new ultrasound techniques and special diagnostic behaviour of GIST and outline clinical pathways to deal correctly with different stages of the disease.