Contrast-enhanced ultrasound of the liver: Vascular pathologies and interventions

Over the past two decades, contrast-enhanced ultrasound (CEUS) has been established as a method complementary to B-mode ultrasound and color Doppler sonography for diagnosing vascular liver pathologies and interventions.The objective of this review is to elucidate the application of CEUS in diagnosing vascular pathologies and interventional procedures.Considering the limitations of ultrasound, CEUS presents a similar alternative to other imaging modalities, such as computed tomography and magnetic resonance imaging, for evaluating vascular pathologies, guiding interventions, identifying complications, and assessing outcomes post intervention. Due to its widespread availability and the absence of radiation exposure, CEUS should be employed as a primary modality. · CEUS plays an important role in the detection of vascular liver pathologies.. · CEUS is helpful in characterizing vascular pathologies.. · CEUS is helpful in guiding interventions and identifying complications..

The value of contrast-enhanced ultrasound in percutaneous biopsy of retroperitoneal masses

PURPOSE

To evaluate the diagnostic yield of contrast-enhanced ultrasound (CEUS)-guided biopsy of retroperitoneal masses (RMs).

MATERIALS AND METHODS

Between 2006 and 2023, 87 patients presented at our US center for biopsy of an RM. In all biopsies, CEUS was performed prior to the intervention. The technical success rate of biopsy, the presence of diagnostic tissue in solid tumor biopsy samples, the accuracy of the biopsy and the occurrence of post-interventional complications were evaluated.

RESULTS

A US-guided biopsy could be conducted in 84/87 cases (96.6%). In 3/87 cases (3.4%), US-guided biopsy was impossible because the planned needle path was obstructed by vital structures. Of 84 lesions, 80 (95.2%) were solid lesions, and 4 (4.8%) were lesions containing fluid. In all solid tumors, 80/80 (100%), diagnostic vital tissue was successfully obtained. CEUS-guided biopsy showed a sensitivity of 93.2%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 72.2%, and a diagnostic accuracy of 94.2% for the differentiation between malignant and benign RMs. In one of the 84 cases (1.2%), there was a complication of postinterventional abdominal pain.

CONCLUSION

Percutaneous CEUS-guided biopsy is a safe procedure with a high diagnostic yield and a low complication rate.

Contrast-enhanced ultrasound of the liver: basics and interpretation of common focal lesions

Over the past 20 years, contrast-enhanced ultrasound (CEUS) has become established as a procedure that is complementary to B-mode ultrasound and color Doppler sonography.The aim of this review is to provide the fundamental knowledge required for examining the liver with CEUS. Additionally, the characteristic CEUS patterns of frequent focal liver lesions are described.Considering the limitations of ultrasound, CEUS offers an equivalent alternative to other imaging modalities, such as computed tomography and magnetic resonance imaging, for evaluating focal liver lesions. It should be utilized as a primary modality due to its lack of radiation exposure and rapid availability. KEY POINTS::   · CEUS plays an important role particularly in the detection and evaluation of incidentally detected liver lesions.. · Considering the limitations of ultrasound, CEUS offers an equivalent alternative to other imaging modalities, such as CT and MRI, for evaluating focal liver lesions.. CITATION FORMAT: · Safai Zadeh E, Prosch H, Ba-Ssalamah A et al. Contrast-enhanced ultrasound of the liver: basics and interpretation of common focal lesions. Fortschr Röntgenstr 2024; DOI: 10.1055/a-2219-4726.

Performance of a low gain avalanche detector in a medical linac and characterisation of the beam profile

Low gain avalanche detectors can measure charged particle fluences with high speed and spatial precision, and are a promising technology for radiation monitoring and dosimetry. A detector has been tested in a medical linac where single particles were observed with a time resolution of 50 ps. The integrated response is similar to a standard ionising chamber but with a spatial precision twenty times finer, and a temporal precision over 100 million times better, with the capability to measure the charge deposited by a single linac pulse. The unprecedented resolving power allows the structure of the ∼3 μs linac pulses to be viewed and the 350 ps sub-pulses in the train to be observed.

Functional capacities of microbial communities to carry out large scale geochemical processes are maintained during ex situ anaerobic incubation

Mechanisms controlling CO₂ and CH₄ production in wetlands are central to understanding carbon cycling and greenhouse gas exchange. However, the volatility of these respiration products complicates quantifying their rates of production in the field. Attempts to circumvent the challenges through closed system incubations, from which gases cannot escape, have been used to investigate bulk in situ geochemistry. Efforts towards mapping mechanistic linkages between geochemistry and microbiology have raised concern regarding sampling and incubation-induced perturbations. Microorganisms are impacted by oxygen exposure, increased temperatures and accumulation of metabolic products during handling, storage, and incubation. We probed the extent of these perturbations, and their influence on incubation results, using high-resolution geochemical and microbial gene-based community profiling of anaerobically incubated material from three wetland habitats across a permafrost peatland. We compared the original field samples to the material anaerobically incubated over 50 days. Bulk geochemistry and phylum-level microbiota in incubations largely reflected field observations, but divergence between field and incubations occurred in both geochemistry and lineage-level microbial composition when examined at closer resolution. Despite the changes in representative lineages over time, inferred metabolic function with regards to carbon cycling largely reproduced field results suggesting functional consistency. Habitat differences among the source materials remained the largest driver of variation in geochemical and microbial differences among the samples in both incubations and field results. While incubations may have limited usefulness for identifying specific mechanisms, they remain a viable tool for probing bulk-scale questions related to anaerobic C cycling, including CO₂ and CH₄ dynamics.

Verification of redox-processes as switching and retention failure mechanisms in Nb:SrTiO3/metal devices

Nanoscale redox reactions in transition metal oxides are believed to be the physical foundation of memristive devices, which present a highly scalable, low-power alternative for future non-volatile memory devices. The interface between noble metal top electrodes and Nb-doped SrTiO3 single crystals may serve as a prominent but not yet well-understood example of such memristive devices. In this report, we will present experimental evidence that nanoscale redox reactions and the associated valence change mechanism are indeed responsible for the resistance change in noble metal/Nb-doped SrTiO3 junctions with dimensions ranging from the micrometer scale down to the nanometer regime. Direct verification of the valence change mechanism is given by spectromicroscopic characterization of switching filaments. Furthermore, it is found that the resistance change over time is driven by the reoxidation of a previously oxygen-deficient region. The retention times of the low resistance states, accordingly, can be dramatically improved under vacuum conditions as well as through the insertion of a thin Al2O3 layer which prevents this reoxidation. These insights finally confirm the resistive switching mechanism at these interfaces and are therefore of significant importance for the study and application of memristive devices based on Nb-doped SrTiO3 as well as systems with similar switching mechanisms.

[Vacuum-assisted closure therapy. Current status and basic research]

The gap between the broad clinical use of vacuum-assisted closure therapy (VT) and knowledge of the physiological mechanisms leading to its effectiveness is great. The value of the technique and its future development are dependent on research into these mechanisms. A meta-analysis evaluating the results of basic research on the effectiveness of VT was carried out based on peer reviewed publications. This is considered in relation to other therapeutic approaches of basic research to wound healing (growth factors etc.). Our study includes a concise description of the scientific background to the mechanisms of cell stimulation using basic work on tissue expansion, bone, vessel and nerve distraction as well as in vitro cell stimulation. Evaluation of the scientific data on all known effects of VT was made based on the results from experimental animal studies, the results of randomized clinical studies, observations on clinical applications and case reports. Assessment of the studies was based on design and significance as well as the appraisal of our own clinical experience. Data involving cellular effects (proliferation, synthesis, wound healing), systemic effects (mediators, systemic inflammatory disease), extracellular effects (perfusion, edema, local wound environment, stabilization, barriers) and complex effects of VT (inflammation, matrix function, blood supply) were examined. Systematic analysis of the data allows scientifically interested surgeons rapid access to the theme, the first, to this extent, extensive overview of the current scientific situation as well as a comprehensive bibliography for all areas involving the theme of mechanical cell stimulation. The authors list major areas for future research and encourage the development of multicenter studies.

Der Einsatz des Ballondissektors in der Expanderchirurgie: Zehn Jahre Erfahrung in der plastischen und rekonstruktiven Chirurgie

BACKGROUND

The use of the balloon dissector ("space maker") for the implantation of soft tissue expanders is illustrated and technical aspects and advantages are compared to the conventional method.

PATIENTS AND METHODS

Over a 10-year period a group of 90 patients with evaluation records (m = 34, f = 56) was analysed retrospectively. The mean age was 23 years (range: 5 to 62 years). Overall, 164 expanders were implanted and in 73 cases (44.5%) a balloon dissector was used.

RESULTS

The mean intraoperative expander filling was increased up to 27% of the volume of the tissue expander after using the balloon dissector; in contrast it was 15% after conventional dissection. The mean duration of expansion was decreased by 9.8% after space maker dissection.

CONCLUSION

The use of the space maker is a scar-sparing technique. Time of operation and overall duration of expansion are reduced. Patient comfort is clearly improved. The negligible costs of a space maker are compensated by the cost reduction due to shorter operating time, fewer outpatient contacts and a low complication rate. The indications for the use of balloon dissectors are the expansion of skin (scar correction after burns, trauma, tumour), breast reconstruction and augmentation, and the prefabrication and rapid intraoperative expansion of musculocutaneous flaps.

[Intestinal lymphoma. A long diagnostic path]

CASE REPORT

We describe the case of a 43-year-old patient with a Burkitt lymphoma in the small intestine, who initially presented with abdominal discomfort, weight loss, constipation and neurological symptoms.

DIAGNOSIS

In terms of differential diagnosis other inflammatory and tumorous diseases had to be considered. Non-Hodgkin lymphomas are common malignant afflictions of the GI-tract. The total body tumor burden is the principal determinant of prognosis. Serum lactate dehydrogenase (LDH) level is one parameter that reflects the tumor burden. On the other hand abdominal mass, bone marrow and central nervous system involvement are negative prognostic factors. Lymphomas can invade in the CNS at any time during the course of disease. This is generally associated with a poor prognosis if not treated immediately.

TREATMENT

High doses of cyclophosphamid and MTX have been shown successful in the treatment of Burkitt lymphoma. Almost all relapses occur on therapy or shortly after termination of treatment. Therefore, criteria are needed to select patients of higher and lesser risk to protect the latter from the further intensification of therapy.

Immunohistochemical and glycohistochemical localization of the beta-galactoside-binding S-type lectin in human placenta

The localization of the beta-galactoside binding lectin was studied immunohistochemically on acetone-fixed cryostat sections of full-term placental tissue using a biotinylated monoclonal antibody and glycohistochemically applying biotinylated asialofetuin and lactosylated bovine serum albumin. On blots of placental tissue lysates the lectin is recognized by the biotinylated lactosylated bovine serum albumin. The glycoconjugate recognition of the lectin on blots was inhibited in the presence of 0.1 M lactose showing the specificity of the interactions. The anti-lectin monoclonal antibody stained syncytiotrophoblast and trophoblastic cells. Both reagents applied for glycohistochemistry stained syncytiotrophoblast and trophoblastic cells of placental villi and the trophoblastic layer of extraplacental membranes. A strong uniform cytoplasmic staining was characteristic for syncytiotrophoblast and to a lower extent for cytotrophoblastic cells. The localization of the lectin is discussed with respect to a possible immunosuppressive function.