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Gray-scale and color/power Doppler ultrasound (US) are the first-line imaging modalities to evaluate the spleen, gallbladder and pancreas in children. The increasing use of contrast-enhanced ultrasound (CEUS) as a reliable and safe method to evaluate liver lesions in the pediatric population promises potential for imaging other internal organs. Although CEUS applications of the spleen, gallbladder and pancreas have been well described in adults, they have not been fully explored in children. In this manuscript, we present an overview of the applications of CEUS for normal variants and diseases affecting the spleen, gallbladder and pancreas. We highlight a variety of cases as examples of how CEUS can serve in the diagnosis and follow-up for such diseases in children. Our discussion includes specific examination techniques; presentation of the main imaging findings in various benign and malignant lesions of the spleen, gallbladder and pancreas in children; and acknowledgment of the limitations of CEUS for these organs.

The ability to provide prompt, real-time, easily accessible and radiation-free diagnostic assessments makes ultrasound (US) one of the most versatile imaging modalities. The introduction and development of stable microbubble-based ultrasound contrast agents (UCAs) in the early 1990s improved visualization of complex vascular structures, overcoming some of the limitations of B-mode and Doppler imaging. UCAs have been used extensively in the adult population to visualize vasculature and to evaluate perfusion and blood flow dynamics in organs and lesions. Since the first observations that air bubbles within a liquid can generate a strong echogenic effect, to the early makeshift approaches with agitated saline, and later to the development of industrially produced and federally approved UCAs, these agents have evolved to become both clinically and commercially viable. Perhaps the most exciting potential of UCAs is being uncovered by current research that explores the use of these agents for molecular imaging and therapeutic applications. As contrast-enhanced ultrasound (CEUS) becomes more widely available, it is important for pediatric radiologists to understand the physics of the interaction between the US signal and the microbubbles in order to properly utilize them for the highest level of diagnostic imaging and interventions. In this article we introduce the composition of UCAs and the physics of their behavior in US, and we offer a brief history of their development over the last decades.

In pediatric and adult populations, intravenous contrast-enhanced ultrasound (CEUS) remains off-label for imaging of organs other than the liver and heart. This limited scope inhibits potential benefits of the new modality from a more widespread utilization. Yet, CEUS is potentially useful for imaging small organs such as the thyroid gland, lymph nodes, testes, ovaries and uterus, with all having locations and vasculature favorable for this type of examination. In the adult population, the utility of CEUS has been demonstrated in a growing number of studies for the evaluation of these small organs. The aim of this article is to present a review of pediatric CEUS of the thyroid gland, lymph nodes, testes, ovaries and uterus as well as to draw from the adult literature indications for possible applications in children. Supplementary Information The online version contains supplementary material available at 10.1007/s00247-021-05006-x.

When performing contrast-enhanced ultrasound (CEUS), ultrasound (US) scanner settings, examination technique, and contrast agent dose and administration must be optimized to ensure that high-quality, diagnostic and reproducible images are acquired for qualitative and quantitative interpretations. When carrying out CEUS in children, examination settings should be tailored to their body size and specific indications, similar to B-mode US. This review article details the basic background knowledge that is needed to perform CEUS optimally in children, including considerations related to US scanner settings and US contrast agent dose selection and administration techniques.

Gray-scale and color/power Doppler ultrasound (US) are the first-line imaging modalities to evaluate the spleen, gallbladder and pancreas in children. The increasing use of contrast-enhanced ultrasound (CEUS) as a reliable and safe method to evaluate liver lesions in the pediatric population promises potential for imaging other internal organs. Although CEUS applications of the spleen, gallbladder and pancreas have been well described in adults, they have not been fully explored in children. In this manuscript, we present an overview of the applications of CEUS for normal variants and diseases affecting the spleen, gallbladder and pancreas. We highlight a variety of cases as examples of how CEUS can serve in the diagnosis and follow-up for such diseases in children. Our discussion includes specific examination techniques; presentation of the main imaging findings in various benign and malignant lesions of the spleen, gallbladder and pancreas in children; and acknowledgment of the limitations of CEUS for these organs.

The increasing use of contrast-enhanced ultrasound (CEUS) has opened exciting new frontiers for musculoskeletal applications in adults and children. The most common musculoskeletal-related CEUS applications in adults are for detecting inflammatory joint diseases, imaging skeletal muscles and tendon perfusion, imaging postoperative viability of osseous and osseocutaneous tissue flaps, and evaluating the malignant potential of soft-tissue masses. Pediatric musculoskeletal-related CEUS has been applied for imaging juvenile idiopathic arthritis and Legg-Calvé-Perthes disease and for evaluating femoral head perfusion following surgical hip reduction in children with developmental hip dysplasia. CEUS can improve visualization of the capillary network in superficial and deep tissues and also in states of slow- or low-volume blood flow. In addition, measurements of blood flow imaging parameters performed by quantitative CEUS are valuable when monitoring the outcome of treatment interventions. In this review article we present current experience regarding a wide range of CEUS applications in musculoskeletal conditions in adults and children, with emphasis on the latter, and discuss imaging techniques and CEUS findings in musculoskeletal applications.

Hydrodynamic journal bearings are essential components in the internal combustion engines. The prediction of their reliability, durability, and economy, and also of their friction loss power and wear, are of highest importance. For an appropriate representation of the hydrodynamic load-carrying capacity and also the friction behavior, the multibody dynamics of the contacting components, the shape of the contacting component surfaces, the amount of the available lubricant, and the properties of the lubricant itself are of importance. A Reynolds-averaged equation with laminar flow conditions in combination with a dry asperity contact model and a multibody dynamic simulation of the structural components is a typical modeling approach for that purpose. Furthermore, this paper shows a newly developed model for the temperature distribution in the lubricant and the bearing structures. It includes thermal interface conditions between these domains, which incorporates the asperity energy source and predicts the temperature in supply areas. The presented method is applied for a typical engineering task of a sensitivity analysis for oils with different viscosity index improvers in a main bearing of a four-cylinder inline diesel engine. The influence of the oil film temperature on the oil film viscosity and, therefore, on the load-carrying capacity is shown. Furthermore, the simplified two-dimensional approach is compared with a three-dimensional approach in terms of the obtained result. The presented results show similar accuracy of the two-dimensional approach compared to the equivalent three-dimensional case.

Journal bearings are key components in internal combustion engines. Their reliability, durability, and economy are of highest importance. Especially, the accurate prediction of friction loss power and wear are essential for the development of an engine. For an appropriate representation of the hydrodynamic load-carrying capacity and also the friction behavior, both the dynamics of the contacting components, the shape of the contacting component surfaces, the amount of the available lubricant, and the properties of the lubricant itself are of importance. A Reynolds-averaged equation with laminar flow conditions in combination with an asperity contact model is a typical modeling approach for that purpose. The lubricant properties are in particular influenced by its thermal conditions on one hand. On the other hand, the thermal conditions are influenced by the mixed lubricated contact conditions as well. These interactions require a coupled modeling approach, which combines the component flexibility and its interaction with load-carrying capacity as well as the thermal behavior of the lubricant and the component surfaces. In this work, a thermo-elasto-hydrodynamic contact model is presented, which computes the oil film temperature using a 2D energy equation. The 2D equation is derived from the equivalent 3D energy equation by integration over the clearance gap height. Besides component material properties such as specific heat capacity, density, heat conductivity for lubricant and structures, also heat transfer through mixed lubricated regimes and partly filled clearance gaps, as implied in cavitation regions, are being considered. The presented method is applied for a typical engineering task of a sensitivity analysis for oils with different viscosity index (VI) improvers in a main bearing of a four-cylinder inline diesel engine. The influence of the oil film temperature on the oil film viscosity and therefore on the load-carrying capacity is shown. Furthermore, the simplified 2D approach is compared with a 3D approach both in terms of obtained result data and in terms of elapsed calculation times. The presented results show similar accuracy of the 2D approach with significantly reduced simulation time compared to the equivalent 3D case.

Adhesive wafer-level bonding is an excellent solution to meet the stringent requirements in micro-electro-mechanical systems (MEMS) packaging, one of the challenges in MEMS manufacturing, in a steadily growing micro-systems market. A range of bonding processes for commercially available substrate bonders have been developed, which apply global heating during the bonding procedure. This article, however, describes an approach where heating is kept to a minimum by combining the merits of laser joining, a truly localised heating technique, and adhesive wafer-level bonding. This unique bonding technique, which enables the use of temperature-sensitive materials within the package, is demonstrated for bonding of silicon to glass – materials commonly used in MEMS fabrication – with a benzocyclobutene (BCB) intermediate bonding layer. As a proof of concept for wafer-level packaging, bonding of two simplified patterns is demonstrated, one with five individual samples on the same wafer, and the other with nine samples. To verify the influence of this innovative bonding technique on the quality of the seal the devices are shear force tested and the results are compared with those of devices packaged at chip-level.

Background Chronic granulomatous disease (CGD) patients are susceptible to recurrent opportunistic infections and to recurrent or chronic inflammations of presumably non-infectious origin. Both types of manifestations are often accompanied by granuloma formation. Both can remain unnoticed until they deteriorate considerably and can become life-threatening if not treated in time. Objective To evaluate the effectiveness of regular follow-up visits in CGD patients. Methods Findings of imaging (ultrasound, radiographs, computer-tomography, magnetic resonance imaging), lung function tests, histopathological and microbiological assessments of biopsies have been reviewed. Results A total of 32 CGD patients have been evaluated within 15 years. Of these eight patients have been checked regularly for more than 5 years. Early detection prior to specific clinical signs and consecutive treatment of six lung manifestations and one liver manifestation such as interstitial pneumonia with formation of small granulomas, formation of large granulomas, fibrosis, Aspergillus infections, and abscesses could presumably prevent considerable aggravation in seemingly healthy or mildly symptomatic patients. In contrast, patients without surveillance who presented with severe symptoms (seven manifestations) often had irreversible organ damage or even died. Conclusions Regular follow-up visits can help prevent or mitigate clinical manifestations, improve life quality and expectancy and weigh indication for bone marrow transplantation in CGD patients.

The courses of 79 children (2 weeks to 19 years old) treated with two different low-molecular weight heparins (LMWHs)--nadroparin (n=66) and enoxaparin (n=13)--were retrospectively analysed. In 62 patients, LMWHs were given for short-term prophylaxis (1-2 weeks) during immobilization after surgery or trauma. Thirteen children with thromboembolic events received long-term prophylaxis with LMWHs for 2-18 months--six after thrombolytic therapy and seven after therapy with unfractionated heparin (UFH). Because of thromboembolic events, four patients were initially treated with LMWHs. In all patients with short-term prophylaxis, no thrombosis occurred. After thrombolytic therapy, three children had no reocclusion, two had no thrombus apposition and one had complete recanalization. In the seven patients treated with LMWHs after UFH, four had no reocclusion, two had recanalization and one had reocclusion. In all patients receiving LMWHs for initial treatment of thrombosis, no thrombus apposition, but also no recanalization, occurred. For short-term prophylaxis, nadroparin was used independent of the body weight and without determination of anti-factor Xa (anti-FXa) activity. Long-term prophylaxis was given mainly as doses of 45-100 anti-FXa U/kg resulting in anti-FXa activities between 0.2 and 0.4 U/ml. For treatment of thrombosis, doses of 200-300 anti-FXa U/kg corresponded to 0.5-1.0 anti-FXa U/ml. Side effects--slight gastrointestinal bleeding and temporary reversible hair loss--were seen in two patients. In conclusion, LMWHs proved to be efficacious and safe especially in prophylaxis of thromboembolic events in children.

Der katheterinterventionelle Verschluss eines Vorhofseptumdefektes ist fur ausgewahlte Patienten eine allgemein akzeptierte Alternative zur chirurgischen Therapie. Limitierende Faktoren sind die bisher bei allen entwickelten Verschlusssystemen aufgetretenen Komplikationen und die fur einige Systeme sehr komplizierte Implantationstechnik. Berichtet wird uber einen 17-jahrigen Patienten, bei dem es knapp 4 Jahre nach katheterinterventionellem ASD-Verschluss mit einem 35mm-ASDOS-Device® (geschutztes Warenzeichen der Dr.Osypka GmbH / Grenzach-Wyhlen, Deutschland) zu einer Embolisation eines frakturierten Schirmarmes in einen peripheren Ast der linken Lungenarterie kam. Die Perfusionsszintigraphie der linken Lunge zeigte eine normale Durchblutung. Echokardiographisch lag keine Instabilitat des Schirmes vor. Der Patient war immer beschwerdefrei. Obwohl implantierbare Schirmsysteme einer standigen Entwicklung und Verbesserung unterliegen, wurde das optimale Device noch nicht gefunden. Durch mechanische Dauerbelastung der Systeme sind Spatfrakturen und Embolisationen von Fragmenten moglich. Patienten mit ASD-Okkludern sollten deshalb auch bei Beschwerdefreiheit lebenslang nachkontrolliert werden.

Ungefahr 30 bis 50% aller Patienten mit kongenitaler Muskeldystrophie weisen einen Mangel an Merosin (Laminin-2-α2), einen Bestandteil der extrazellularen Matrix, auf. Diese Erkrankung geht bei der Mehrzahl der Patienten mit einer Leukenzephalopathie einher, die durch ein kraniales MRT diagnostiziert werden kann. Im folgenden stellen wir ein Kleinkind mit unklarer kongenitaler Muskeldystrophie und akuter kongestiver Herzinsuffizienz vor, bei dem durch ein kraniales MRT eine schnelle und nichtinvasive Einordnung der Grunderkrankung moglich war.

In recent years various techniques have been developed for the manufacture of microsystems and other miniature optoelectronic devices. One aspect where there remains significant room for improvement is the packaging process. Standard packaging techniques involve heating whole devices to high temperatures, in some cases combined with strong electric fields, preventing the use of temperature-sensitive materials within the package and generating problems in manufacturing processes where a number of thermal process steps are carried out sequentially, when a later heating step can cause parts joined earlier to disassemble. Here we describe the successful application of laser-based joining for the packaging of such devices.

In this paper, we investigate the feasibility of using a laser as the heat source to drive a hermetic joining process based on a glass frit intermediate layer. The laser allows the necessary heat energy to be provided in a localized manner; important either as part of a multistage process, or to allow thermally-sensitive materials to be used inside the package. Our study includes an investigation of the impact of rough and grooved surfaces on the hermeticity and strength of the join, demonstrating the robust nature of the process, and its ability to allow feed-throughs to the center of package. Hermetic sealing is demonstrated, with leak rates of 10−9 mbar l s−1, satisfying the military standard MIL-STD-883G.

In recent years there has been significant interest in the development of new types of Micro-Electro-Mechanical-Systems (MEMS) and related micro-devices but the issue of packaging remains a problem in many cases, and is indeed a particular challenge for their commercialisation. Current hermetic bonding techniques involve heating the whole device to high temperatures, in some cases combined with strong electric fields. This prevents the use of temperature-sensitive materials within the package polymer and magnetic materials). We have therefore been developing alternative solutions based on the use of a laser as a truly localised heat source to drive an intermediate layer bonding process. In this paper we describe laser-based packaging of silicon to glass - materials commonly used in MEMS fabrication - on a wafer-level, where multiple devices are packaged on a single silicon wafer. The bonding is achieved by using a Benzocyclobutene intermediate layer. Previously we have demonstrated bonding of a simplified pattern of 5 individual packages on the same chip as a proof of principle. In this work we present packaging of more complex and more closely spaced patterns and the issues involved in such processes when using laser bonding.In recent years there has been significant interest in the development of new types of Micro-Electro-Mechanical-Systems (MEMS) and related micro-devices but the issue of packaging remains a problem in many cases, and is indeed a particular challenge for their commercialisation. Current hermetic bonding techniques involve heating the whole device to high temperatures, in some cases combined with strong electric fields. This prevents the use of temperature-sensitive materials within the package polymer and magnetic materials). We have therefore been developing alternative solutions based on the use of a laser as a truly localised heat source to drive an intermediate layer bonding process. In this paper we describe laser-based packaging of silicon to glass - materials commonly used in MEMS fabrication - on a wafer-level, where multiple devices are packaged on a single silicon wafer. The bonding is achieved by using a Benzocyclobutene intermediate layer. Previously we have demonstrated bonding of a simplified...

The use of a laser to provide localised heating is an ideal solution to the problem of packaging micro-electro-mechanical-systems (MEMS) whilst maintaining a low device temperature to avoid changes in temperature-sensitive materials in the device. In this paper we present localised laser bonding of glass to silicon (normally used as the MEMS substrate) by using a fibre-delivered high power laser diode array to cure an intermediate layer of the thermosetting polymer Benzocyclobutene (BCB). In our experiments, we use two techniques to realise localised heating: one is to use an axicon together with a conventional positive lens to generate a ring focus; the other is to use a scanning focused laser beam. In both cases localised cooling is required to confine the elevated temperatures to the bonding area. Finite Element (FE) simulation indicates that both techniques should keep the temperature in the centre of the package to approximately that of the ambient environment (300 K) during the process. However, experiments show that the temperature in the centre of the package rises to a value of around 500 K, likely due to poor contact between silicon and cooling sink. Experimentally, we confirmed that either technique can be used to obtain excellent bonding of glass to silicon with leak rate at a level of 10−10 mbar l s−1, whilst keeping the centre of device at a lower temperature.

In this paper we investigate and compare a laser-driven joining process with two different illumination conditions: (i) high speed scanning of a focused beam and (ii) reasonably uniform “flood illumination” of the whole sample. It is shown that the scanning beam not only avoids illuminating the central part of the device, but also provides more uniform heating of the area to be bonded than laser “flood illumination”. We demonstrate bonding of three different packages: (i) LCC (Leadless chip carrier) packages, (ii) AlN and (iii) LTCC (Low temperature co-fired ceramic) substrates to “top-hat” packages, using a scanned beam from a fibre-delivered high power laser diode array to cure an intermediate layer of glass frit. Standard leak testing demonstrates that all those samples have excellent hermetic sealing with leak rates at the level of 10−9 atm·cc/s.In this paper we investigate and compare a laser-driven joining process with two different illumination conditions: (i) high speed scanning of a focused beam and (ii) reasonably uniform “flood illumination” of the whole sample. It is shown that the scanning beam not only avoids illuminating the central part of the device, but also provides more uniform heating of the area to be bonded than laser “flood illumination”. We demonstrate bonding of three different packages: (i) LCC (Leadless chip carrier) packages, (ii) AlN and (iii) LTCC (Low temperature co-fired ceramic) substrates to “top-hat” packages, using a scanned beam from a fibre-delivered high power laser diode array to cure an intermediate layer of glass frit. Standard leak testing demonstrates that all those samples have excellent hermetic sealing with leak rates at the level of 10−9 atm·cc/s.

Im Zeitraum von April 1983 bis Dezember 1999 fuhrten wir 108 Ductusligaturen bei extrem unreifen Fruhgeborenen durch. Das mittlere Geburtsgewicht betrug 1050 g. Das mittlere Gestationsalter war 27,6 Wochen. 58,3% der Kinder waren mit Indomethazin vorbehandelt. Vor Einfuhrung der Surfactant — Therapie betrug die Letalitat der operierten Kinder 36%. Nach Einfuhrung der Surfactant-Therapie im Jahre 1990 fiel sie auf 13,8%. Von den 82 lebenden Kindern konnten 64 (78%) nachuntersucht werden. Folgende Befunde wurden erhoben: 1. 13 Kinder hatten schwere neurologische Defekte. 2. Bei 8 Kindern wurde eine Stimmbandparese links festgestellt. 3. Bei keinem Kind wurde als Thorakotomiefolge eine behandlungsbedurftige Skoliose festgestellt. Von 48 Kindern, die mit einer behandlungsbedurftigen BPD entlassen wurden, war bei dem Eintritt in die Schule bei keinem Kind eine Therapie der BPD mehr erforderlich. Hirnblutungen dritten und vierten Grades sehen wir als Kontraindikation fur eine Ductusligatur.

Glass frit packaging is a simple and robust method used for hermetic sealing of micro-devices. Conventional glass frit packaging processes rely on furnace heating where the entire package is heated to elevated temperatures, hence restricting the use of temperature-sensitive materials inside the package and generating problems in multi-stage packaging processes. The use of a laser as an alternative heat source offers the possibility of highly localized heating where the heat-input can be restricted to the joining area only. In this paper the clear benefits of combining glass frit packaging and localized laser heating are demonstrated. Two novel laser-based glass frit packaging processes for sealing of leadless chip carrier (LCC) packages in both air and vacuum have been developed. Full hermetic seals according to MIL-STD-883G are achieved in high yield processes where the temperature in the centre of the device is kept at least 230 °C below the temperature in the joining region.

One of the remaining issues in the fabrication of micro-devices, including MEMS, is the packaging process. Standard techniques involve heating the whole device to high temperatures, preventing the use of temperature-sensitive materials within the package (e.g. polymer and magnetic materials) and generating problems in manufacturing processes where a number of thermal process steps are carried out in sequence, when a later heating step can cause parts joined earlier to disassemble. In our previous studies we demonstrated that it is feasible to combine the benefits of intermediate layer bonding and laser heating to achieve packaging processes where the required high temperatures are highly localised. Previously only single chip packaging was presented and therefore in this paper we demonstrate solutions to the issues involved in laser-based wafer-level packaging, where many devices are packaged on a single silicon wafer. In this case our example is a silicon-glass package using a Benzocyclobutene intermediate layer – materials commonly used in MEMS fabrication. We also report on developments for packages requiring a moderate vacuum with long-term stability. Here a glass-frit based process using localised laser heating is described.One of the remaining issues in the fabrication of micro-devices, including MEMS, is the packaging process. Standard techniques involve heating the whole device to high temperatures, preventing the use of temperature-sensitive materials within the package (e.g. polymer and magnetic materials) and generating problems in manufacturing processes where a number of thermal process steps are carried out in sequence, when a later heating step can cause parts joined earlier to disassemble. In our previous studies we demonstrated that it is feasible to combine the benefits of intermediate layer bonding and laser heating to achieve packaging processes where the required high temperatures are highly localised. Previously only single chip packaging was presented and therefore in this paper we demonstrate solutions to the issues involved in laser-based wafer-level packaging, where many devices are packaged on a single silicon wafer. In this case our example is a silicon-glass package using a Benzocyclobutene intermedia...