[Contrast-enhanced ultrasound in the diagnostic workup of lymph nodes]. / Kontrastverstärkte Sonographie in der Lymphknotendiagnostik.

CLINICAL/METHODICAL ISSUE: Daily tasks in sonographic diagnostics include detection and characterization of peripheral and abdominal lymph nodes. STANDARD RADIOLOGICAL METHODS: In addition to the B­mode methods, color-coded Doppler sonography (CCDS) plays an important role in the evaluation of lymph nodes. METHODICAL INNOVATIONS: Contrast-enhanced ultrasound (CEUS) has become a standard procedure in vascular and organ diagnostics. Tissue perfusion can be recorded visually and retrospectively in real time using time-dependent intensity analysis. The contrast agent dosage depends primarily on the location of the lymph nodes and the type and frequency of the transducer. Vascular and tumor cell density, intranodal pressure due to increased vascular permeability and preservation or destruction of the capsule must be taken into account when interpreting the findings. PERFORMANCE: The indication for CEUS results from the B­mode and CCDS findings and plays an important role especially in the verification of vitality before and after therapy. Uneven or apparently non-perfused areas allow a targeted puncture of vital tumor tissue. ACHIEVEMENTS: Especially in abdominal lymph nodes, CEUS has a high diagnostic reliability. It is not always possible to differentiate between inflamed lymph nodes and lymph nodes altered by lymphoma filtration. PRACTICAL RECOMMENDATIONS: CEUS helps to better assess the dignity of lymph nodes by visualizing their micro- and macrovascularization. After frustrated puncture, vital areas can be specifically biopsied. CEUS is particularly valuable in assessing the success of therapy.

Growing indications for CEUS: The kidney, testis, lymph nodes, thyroid, prostate, and small bowel.

Contrast enhanced ultrasonography (CEUS) is increasingly used for non-hepatic applications as well, so that nearly all organs have been investigated. Among them, there is a growing clinical use for a variety of pathologies of the kidney, testis, and small bowel. The possibility to differentiate benign from malignant nodes in cancer patients has been investigated. A new application is in the detection of sentinel nodes after intradermal microbubble injection. The need to distinguish thyroid nodules eligible for fine needle aspiration cytology has led to the use of CEUS in thyroid examinations as well. The potential of CEUS for prostate cancer detection has been extensively investigated, with encouraging initial results. Early promise, however, has not been fulfilled. New perspective regards evaluation of the extent of prostate tissue devascularization following ablative treatments.

Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS.

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

[Ultrasound in the diagnostic management of malignant lymphomas]. / Ultraschall in der Diagnostik maligner Lymphome.

Ultrasound is most useful in detecting and characterizing peripheral and abdominal lymph nodes and infiltration of solid organs. B-mode criteria, such as size, shape, number, distribution architecture, echogenicity and delineation of margins are the basis for characterizing lymph nodes. Additionally color coding techniques such as color Doppler, B-flow and contrast-enhanced ultrasound (CEUS) contribute to the evaluation of the nodal vasculature and vessel architecture. Whenever possible high frequency probes should not only be used for evaluating peripheral lymph nodes but also for lymphatic infiltration of solid organs, especially the spleen. The CEUS technique will be of additional benefit in detecting characterizing potential lymphatic organ infiltration. Ultrasound is an ideal tool for guided punctures, for which core biopsies should be preferred over fine needle aspiration biopsy and CEUS can also be used for proving residual viable tissue after chemotherapy or radiation therapy.

[Detection and characterization of liver metastases]. / Nachweis und Charakterisierung von Lebermetastasen.

Since the advent of second generation ultrasound (US) contrast agents, ultrasound has caught up with other imaging modalities for the detection and characterization of liver metastases and as a result of its high temporal and spatial resolution it can in some cases even be superior to computed tomography (CT) and magnetic resonance imaging (MRI). Many studies have demonstrated a sensitivity and specificity of over 90%. Due to its high temporal resolution contrast-enhanced US (CEUS) is capable of detecting even a very short duration of hyper-enhancement during the arterial phase. Radiation protection and lack of adverse effects on renal or thyroid function are additional arguments why CEUS should be recommended as the first imaging modality in the evaluation of hepatic metastases in cases of favorable scanning conditions.

[New trends in ultrasound diagnostics of carotid stenoses]. / Neue Trends in der Ultraschalldiagnostik der Karotisstenose.

The B-mode image quality of vessels has markedly increased with the advent of new transducer technologies. Morphological changes of the vessel wall, ulcerations, dissections or wall lesions benefit from non-Doppler dependent flow imaging methods. Two-dimensional imaging of the elasticity of the vessel wall may in future benefit from high speed imaging techniques. The biggest improvement in vessel imaging is probably the prudent use of contrast-enhanced ultrasound by which neovascularization can be visualized. Plaque vascularization is looked upon as an important risk factor in the evaluation of possible vulnerable plaques.

Emerging roles for contrast-enhanced ultrasound.

The article considers new and potential uses for contrast-enhanced ultrasound (CEUS) in radiology. CEUS could become an early, sensitive and inexpensive tool for managing tumor ablation in patients in whom microvascular imaging adds diagnostic information, especially in inflammatory diseases. Its sensitivity in detecting focal liver lesions is comparable to that of other imaging modalities such as computed tomography or magnetic resonance imaging, and it provides a high accuracy in lesion characterization. The main indications in renal diseases are characterization of complicated cysts, arterial infarction and masses in the collecting system and renal vein. As local ablation therapy gains clinical acceptance in liver and recently in renal tumors, CEUS may play an important role in planning the procedure, needle navigation and the follow-up of these patients. In rheumatology, monitoring and optimizing the effectiveness of therapy may also become an important task for CEUS. In breast and prostate cancers, CEUS can add diagnostic value, especially in early detection of tumor recurrence. In lung disease, the technique has considerable potential for characterizing non-ventilated tissues and helping with interventional procedures. In vascular disease, CEUS is of value in arterial stenosis, but its greatest benefit may be in characterizing changes within the vessel wall. It also greatly increases the success rate of transcranial examinations. CEUS is expected to play a major role in detecting sentinel lymph nodes and estimating the tumor burden of involved lymphatic tissue. The possible indications and potential benefits of CEUS are numerous and have yet to be fully exploited.

B-flow and B-flow with 3D and SRI postprocessing before intervention and monitoring after stenting of the internal carotid artery.

OBJECTIVE: To investigate the extent to which B-flow and B-flow with 3D postprocessing and speckle reduction imaging (SRI) have advantages in appraising the morphology of a high-grade stenosis of the internal carotid artery (ICA) for preinterventional planning and for postinterventional ultrasonographic follow-up. MATERIALS/METHODS: A comparative appraisal of flow with CCDS, power Doppler, B-flow and 3D B-Flow with SRI were carried out prospectively in 50 patients with >70% stenosis according to NASCET criteria in contrast medium-enhanced MRA before and after the intervention. After stenting of the internal carotid artery (ICA), i.a. digital substraction angiography (DSA) served as an additional reference method. RESULTS: In >70% ICA stenosis, simultaneous imaging of the pre-stenotic, intra-stenotic and post-stenotic flow was attained with B-flow in 45/90 cases (90%), with power Doppler in 39/50 cases (78%) and with CCDS in only 31/50 cases (62%). After intervention, a complete detection of flow without overwriting or blooming artifacts was achieved in all 50 patients only by B-flow. The intrastenotic flow (p<0.05) could be better demarcated against the lumen and the vessel wall before the intervention, whereas the flow within the stent could be very much better appraised after the intervention (p<0.01) using 3D postprocessing of B-flow with additional SRI. Re-stenoses with hypoechoic vascular wall changes (3/50 patients) were detected at an early stage using B-flow. CONCLUSIONS: B-flow technique with SRI and 3D postprocessing can facilitate the intrastenotic detection of flow in >70% ICA stenosis with fewer flow artifacts. After stenting, the perfused vascular lumen shows less flow artifacts compared with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.

New perspectives for the use of contrast-enhanced liver ultrasound in clinical practice.

The introduction of second-generation microbubble ultrasound contrast agents and the development of contrast specific ultrasound techniques have improved the ability of contrast enhanced ultrasound in detecting and characterising liver lesions, offering new perspectives for its exploitation in clinical hepatology. Indeed, several studies have demonstrated a high diagnostic accuracy in focal lesion characterisation (85-96%) in patients either with or without underlying chronic liver disease. This review article describes the basic principles of contrast enhanced ultrasound, defines the different vascular features of benign and malignant liver lesions, and assesses its clinical impact in different clinical scenarios, according to the guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology, contrast enhanced ultrasound enables the characterisation of focal liver lesions, regardless of the presence or absence of underlying chronic liver disease. Contrast enhanced ultrasound is also useful in staging and follow-up of cancer patients and in monitoring local ablative treatment. Contrast enhanced ultrasound is expected to be considerably increased and replace many computed tomography and magnetic resonance imaging examinations in near future, according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines. Therefore, it is necessary to take measures in order to meet the demand for an increasing number of these procedures.

[Malignant hepatobiliary tumors. Surgical requirements concerning preoperative diagnosis]. / Maligne hepatobiliäre Tumore. Anforderungen des Chirurgen an die präoperative Diagnostik.

Depending on the results of the diagnostic work-up of a hepatobiliary tumour, the further therapeutic strategy may vary appreciably. The data needed to decide whether a malignant growth is resectable or not include information on the nature, size and location of the tumour, the number of lesions presenting, extrahepatic tumour-related manifestations, the individual hepatic anatomy and additional liver diseases. Despite the recent technical advances, the various diagnostic imaging procedures all have their limitations; used in combination, however, they can provide adequate information in 90-100% of the cases. The most important of these procedures are ultrasonography and spiral CT--including the use of contrast agents--and in some cases also MRT. Thanks to the topographic information they provide, the three-dimensional methods are gaining popularity. While angiography, scintigraphy and ERCP are useful supplementary methods, they do not suffice for the primary diagnosis. In some cases, intra-operative diagnosis may make necessary a change in the planned therapeutic procedure. The limitations and possibilities of the diagnostic strategy--which in no small part is also codetermined by the patient's prehistory and the experience of the examiner--are discussed.

[B-flow--a new method for detecting blood flow]. / B-Flow--eine neue Methode zur Blutflussdetektion.

A new ultrasound-based blood flow detection method, B-Flow is introduced. The amplitude of scatterers in flowing blood is imaged by a subtraction mode of two to four vectors along one line. Noise reduction is gained by using digital encoded US pulses. Signal enhancement is performed by using a pulse compression method (coded excitation). Compared to Color Doppler (CDI) Imaging B-Flow has a higher time (frame rate) and better spatial resolution. Typical CDI artifacts like color blooming or aliasing are missed. B-Flow does not allow velocity measurements. B-Flow has its clinical value in imaging perfused arterial vessels, simultaneous imaging of high and low velocities and delineating plaque morphology with high resolution.

Angiomyolipoma of the kidney and lymph nodes.

Angiomyolipoma (AML) is a benign mesenchymal tumor predominantly occurring in the kidney. Despite its low incidence of 0.07-0.03% in an unselected population, this tumor is well known, because the typical AML can be diagnosed without histological confirmation by a combination of ultrasound (US) and computerized tomography (CT) imaging in up to 95% of cases. In contrast, simultaneous involvement of the kidney and the regional lymph nodes is less known and might be confused with metastasizing malignant tumor. We report a case of the very uncommon simultaneous involvement of the kidney and the lymph nodes in AML.

US-based evaluation of hemodynamic parameters in the common carotid artery: a nomogram trial.

PURPOSE: To evaluate hemodynamic data of the common carotid artery (CCA) with an ultrasound (US)-based technique in an age- and sex-matched healthy population. MATERIALS AND METHODS: Measurements from a color M-mode tracing of each CCA in 205 healthy subjects (age range, 20-87 years) were performed with a time domain processing system. Lumen change of the color M-mode tracing, flow velocity, volume flow rate, and diastolic volume index (DVI) were calculated five times. Blood pressure was measured after the US examination. Fifteen subjects were excluded from the nomogram trial because of hypertension, and 12 and four subjects were excluded because of an asymptomatic carotid artery stenosis or atrial fibrillation, respectively. RESULTS: Mean volume flow rate in the CCA of the remaining 174 healthy volunteers was 415.0 mL/min +/- 87.0 (men [n = 84], 441.0 mL/min +/- 95.5; women [n = 90], 390.2 mL/min +/- 70.5). The following statistically significant associations were noted: between vessel lumen and sex and blood pressure; between peak systolic velocity and sex and age; between volume flow rate and sex, age, and systolic blood pressure; and between DVI and age, heart rate, and systolic and diastolic blood pressure. CONCLUSION: Time domain processing is an intrasessionally well-reproducible US method for measuring velocities and volume flow in the CCA.

The sensitivity of new color systems in blood-flow diagnosis. The maximum entropy method and angio-color-comparative in vitro flow measurements to determine sensitivity.

BACKGROUND: Two new blood-flow-diagnosis techniques have recently been developed as supplements to the established color techniques: the MEM (maximum entropy method) technique and color flow amplitude (power Doppler). These are capable of representing blood flow in distinctly more slowly flowing areas than is possible with the conventional Doppler technique. METHODS: Both methods make use of the Doppler technique in part, yet analyze the reflected signal in a different manner, in so doing optimizing the relation between the noise and the signal. Measurements were obtained on two anatomic flow models to test the sensitivity of both techniques under slow flow conditions. RESULTS: The slowest flow the MEM technique was capable of recording was 0.5 mm/s, albeit utilizing a 5-MHz transducer for the MEM technique and a 10-MHz transducer for the angio technique. One may thus assume that the MEM technique would be still more sensitive when utilizing a 10-MHz transducer. The advantage of the MEM technique is its real-time flow representation: The angio technique requires a few seconds of acquisition time. This could have serious consequences during clinical utilization. Doppler sonography was merely capable of detecting a minimum flow velocity of 15 mm/s. The angio technique is less dependent on the angle during flow representation than the MEM technique. CONCLUSIONS: The distinctly higher sensitivity of these two new color techniques offers new possibilities in the clinical sector as far as the perfusion diagnosis of organs and tumors is concerned.

Amplitude Doppler US: slow blood flow detection tested with a flow phantom.

PURPOSE: To evaluate the in vitro sensitivity for the detection of slow blood flow in tiny tubes with an amplitude Doppler ultrasound (US) technique at different angles and pulse repetition frequencies. MATERIALS AND METHODS: Human blood treated with heparin was pumped through silicone tubes (flow phantoms made by the author) with lumina of 3.00 mm, 0.30 mm, and 0.05 mm. Slow flow was imaged by using amplitude and color Doppler US techniques with two US devices at different pulse repetition frequencies and angles and in different sound propagation media. RESULTS: Under ideal conditions, the lowest detectable velocity was 0.04-0.06 cm/sec in the 3.00-mm tube. Detection was about three to four times less sensitive in the 0.30-mm and 0.05-mm tubes. Amplitude Doppler US sensitivity is only slightly dependent on the angle of incidence and propagation medium. CONCLUSION: The fractional volume flow determined the sensitivity of the amplitude Doppler technique for detecting low flow. Amplitude Doppler US is nearly angle independent; thus, it is superior to color Doppler US. Amplitude Doppler US is three to four times more sensitive when tube have very tiny lumina and when probes of a lower frequency are used.

[Sensitivity of new color systems: "maximum entropy method" and angio-color. Comparative in vitro flow measurements]. / Sensitivität neuer Farbysteme: "Maximum Entropy Method" und Angio-Farbe. Vergleichende in-vitro-Flussmessungen.

AIM: The sensitivity of the two procedures for slow blood flow velocities in two flow phantoms examined and compared to conventional colour Doppler. METHOD: In two phantoms with vessels between 0.3 and 6 mm diameter the slowest measurable blood flow with the different techniques was determined. The influence of various application angles was also studied. RESULTS: The slowest blood flow velocity detected with the MEM technique was 0.6 mm/s and with the angio-technique 0.4 mm/s. Two different scan-heads were used; a 5 MHz probe for the MEM procedures and a 10 MHz probe for ultrasound angiography. Using a 10 MHz scan-head will most likely lead to increased sensitivity of MEM. Blood flow representation with the MEM technique is real-time, while several seconds of acquisition time are required for the angio-technique, which is a disadvantage during clinical use. Conventional Doppler was merely able to represent 15 mm/s blood flow. The angio-technique was less dependent on the application angle than the MEM procedure. CONCLUSION: The definitely increased sensitivity of the two colour methods open up new areas in the diagnosis of organ and tumour perfusion.