C. F. Dietrich

The EFSUMB guidelines and recommendations on the clinical practice of contrast enhanced ultrasound (CEUS): Update 2011 on non-hepatic applications

Authors F. Piscaglia1, C. Nolsøe2, C. F. Dietrich3, D. O. Cosgrove4, O. H. Gilja5, M. Bachmann Nielsen6, T. Albrecht7, L. Barozzi8, M. Bertolotto9, O. Catalano10, M. Claudon11, D. A. Clevert12, J. M. Correas13, M. D’Onofrio14, F. M. Drudi15, J. Eyding16, M. Giovannini17, M. Hocke18, A. Ignee19, E. M. Jung20, A. S. Klauser21, N. Lassau22, E. Leen23, G. Mathis24, A. Saftoiu25, G. Seidel26, P. S. Sidhu27, G. ter. Haar28, D. Timmerman29, H. P. Weskott30

EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 1: Basic principles and technology.

The technical part of these Guidelines and Recommendations, produced under the auspices of EFSUMB, provides an introduction to the physical principles and technology on which all forms of current commercially available ultrasound elastography are based. A difference in shear modulus is the common underlying physical mechanism that provides tissue contrast in all elastograms. The relationship between the alternative technologies is considered in terms of the method used to take advantage of this. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided on optimisation of scanning technique, image display, image interpretation and some of the known image artefacts.

EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography. Part 2: Clinical Applications

The clinical part of these Guidelines and Recommendations produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology EFSUMB assesses the clinically used applications of all forms of elastography, stressing the evidence from meta-analyses and giving practical advice for their uses and interpretation. Diffuse liver disease forms the largest section, reflecting the wide experience with transient and shear wave elastography . Then follow the breast, thyroid, gastro-intestinal tract, endoscopic elastography, the prostate and the musculo-skeletal system using strain and shear wave elastography as appropriate. The document is intended to form a reference and to guide clinical users in a practical way.

Accuracy of endoscopic ultrasound elastography used for differential diagnosis of focal pancreatic masses: a multicenter study.

BACKGROUND AND STUDY AIMS Endoscopic ultrasound (EUS) elastography represents a new imaging procedure that might characterize the differences of hardness and strain between diseased tissue and normal tissue. The aim of this study was to assess the efficiency of EUS elastography for the differentiation of focal masses in chronic pancreatitis and pancreatic cancer. PATIENTS AND METHODS The study group comprised 258 patients with focal pancreatic masses included prospectively at 13 participating centers. Qualitative analysis of the diagnoses made by two expert doctors using all recorded video clips was performed in order to test the interobserver variability. A post-processing software analysis was used to examine the EUS elastography videos by calculating average-hue histograms of individual elastography images. The quantitative information was used to calculate intra-observer variability and the accuracy of the method. RESULTS Qualitative analysis of the recorded videos revealed a kappa value of 0.72. Intra-observer variability analysis revealed that the single measure intraclass correlation ranged between 0.86 and 0.94. The average-hue histogram analysis of the data indicated a sensitivity of 93.4 %, a specificity of 66.0 %, a positive predictive value of 92.5 %, a negative predictive value of 68.9 %, and an overall accuracy of 85.4 %, based on a cut-off value of 175. Area under the receiver operating characteristic curve (AUROC) was 0.854 ( P < 0.0001) with a confidence interval of 0.804 - 0.894. CONCLUSION The value of quantitative analysis of EUS elastography recordings was proven by good reproducibility of the videos, as well as good parameters of the AUROC analysis. (Clinical Trials.gov identifier: CT00909103).

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 harmonic endoscopic ultrasound.

Second-generation intravenous blood-pool ultrasound contrast agents are increasingly used in endoscopic ultrasound (EUS) for characterization of microvascularization, differential diagnosis of benign and malignant focal lesions, and improving staging and guidance of therapeutic procedures. Although initially used as Doppler signal enhancers, second-generation microbubble contrast agents are now used with specific contrast harmonic imaging techniques, which benefit from the highly nonlinear behavior of the microbubbles. Contrast-specific modes based on multi-pulse technology are used to perform contrast-enhanced harmonic EUS based on a very low mechanical index (0.08 - 0.12). Quantification techniques based on dynamic contrast-enhanced ultrasound have been recommended for perfusion imaging and monitoring of anti-angiogenic treatment, mainly based on time-intensity curve analysis. Most of the clinical applications include the differential diagnosis of focal pancreatic masses, with adenocarcinoma having a distinct hypovascular (hypo-enhanced) appearance compared with neuroendocrine tumors, which are hypervascular (with strong arterial hyper-enhancement). However, pseudotumoral chronic pancreatitis and autoimmune pancreatitis also have an iso- or hypervascular appearance, making the differential diagnosis difficult. Even more promising is the use of dynamic contrast-enhanced harmonic EUS for the longitudinal monitoring of the effects of chemotherapy and/or anti-angiogenic therapy in advanced digestive cancers, which are difficult to examine by conventional cross-sectional imaging techniques.

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-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.