Single-Fiber Transducer Arrays for 3-D Ultrasound Computed Tomography: From Requirements to Results.

A potential method for future breast cancer screening is 3-D ultrasound computed tomography (USCT). The utilized image reconstruction algorithms require transducer characteristics fundamentally different from conventional transducer arrays, leading to the necessity of a custom design. This design has to provide random transducer positioning, isotropic sound emission as well as a large bandwidth and wide opening angle. In this article, we present a new transducer array design to be utilized in a third generation 3-D USCT system. Each system requires 128 cylindrical arrays, mounted into the shell of a hemispherical measurement vessel. Each new array contains a 0.6 mm thick disk with 18 single PZT fibers (0.46 mm diameter) embedded in a polymer matrix. Randomized positioning of the fibers is achieved with an arrange-and-fill process. The single-fiber disks are connected on both ends with a matching and backing disk using simple stacking and adhesives. This enables fast and scalable production. We characterized the acoustic field of 54 transducers with a hydrophone. Measurements in 2-D showed isotropic acoustic fields. The mean bandwidth and opening angle are 131% and 42°, respectively (both -10 dB). The large bandwidth arises from two resonances within the utilized frequency range. Parameter studies using different models showed that the realized design is already close to the achievable optimum for the transducer technology used. Two 3-D USCT systems were equipped with the new arrays. First images show promising results, with an increase in image contrast and a significant reduction of artifacts.

The Impact of COVID-19 on Physical Activity and Life Satisfaction of Golfers: A Cross-Sectional Study in German-Speaking Countries.

Golf is an outdoor sport played worldwide, and golfers of all ages benefit from regular exercise and social contact. The COVID-19 crisis has led to lockdowns, curfews, and closures of golf courses and other indoor and outdoor sports facilities. This study aimed to retrospectively assess how golfers perceived the impact of the crisis on physical activity and life satisfaction. We conducted a cross-sectional online survey among 1,115 golfers (61% men, mean age 55.0 years) in German-speaking countries, mainly Austria and Germany, from March to June 2021. When comparing ratings before and during the COVID-19 period, participants reported exercising more indoors at home independently or with online instructions. Likewise, the popularity of exercising outdoors in publicly accessible open spaces increased overall, especially in rural areas by about 10%. Life satisfaction decreased significantly by 24.2% (p < 0.001) during the pandemic. From a public health perspective, access to outdoor sports facilities such as golf courses might alleviate the negative psychosocial and health effects of home confinement and restricted access to indoor sports facilities. Further research is recommended to evaluate the longer-term impact of COVID-19-related measures on the physical activity and life satisfaction of golfers.

Progressive cholestasis and associated sclerosing cholangitis are frequent complications of COVID-19 in patients with chronic liver disease.

BACKGROUND AND AIMS: Cholestasis is associated with disease severity and worse outcome in COVID-19. Cases of secondary sclerosing cholangitis (SSC) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been described. APPROACH AND RESULTS: Hospitalized patients with COVID-19 between 03/2020 and 07/2021 were included. Patients were stratified as having (i) no chronic liver disease (CLD), (ii) non-advanced CLD (non-ACLD), or (iii) advanced CLD (ACLD). Patients with CLD and non-COVID-19 pneumonia were matched to patients with CLD and COVID-19 as a control cohort. Liver chemistries before (Pre) and at first, second, and third blood withdrawal after SARS-CoV-2 infection (T1-T3) and at last available time point (last) were recorded. A total of 496 patients were included. In total, 13.1% (n = 65) had CLD (non-ACLD: 70.8%; ACLD: 29.2%); the predominant etiology was NAFLD/NASH (60.0%). COVID-19-related liver injury was more common among patients with CLD (24.6% vs. 10.6%; p = 0.001). After SARS-CoV-2 infection, patients with CLD exhibited progressive cholestasis with persistently increasing levels of alkaline phosphatase (Pre: 91.0 vs. T1: 121.0 vs. last: 175.0 U/L; p < 0.001) and gamma-glutamyl transferase (Pre: 95.0 vs. T1: 135.0 vs. last: 202.0 U/L; p = 0.001). A total of 23.1% of patients with CLD (n = 15/65) developed cholestatic liver failure (cholestasis plus bilirubin ≥6 mg/dl) during COVID-19, and 15.4% of patients (n = 10/65) developed SSC. SSC was significantly more frequent among patients with CLD and COVID-19 than in patients with CLD and non-COVID-19 pneumonia (p = 0.040). COVID-19-associated SSC occurred predominantly in patients with NAFLD/NASH and metabolic risk factors. A total of 26.3% (n = 5/19) of patients with ACLD experienced hepatic decompensation after SARS-CoV-2 infection. CONCLUSIONS: About 20% of patients with CLD develop progressive cholestasis after SARS-CoV-2 infection. Patients with NAFLD/NASH and metabolic risk factors are at particular risk for developing cholestatic liver failure and/or SSC after COVID-19.

Age-adjusted mortality and predictive value of liver chemistries in a Viennese cohort of COVID-19 patients.

BACKGROUND AND AIMS: The coronavirus disease of 2019 (COVID-19) causes considerable mortality worldwide. We aimed to investigate the frequency and predictive role of abnormal liver chemistries in different age groups. METHODS: Patients with positive severe acute respiratory distress syndrome-coronavirus-2 (SARS-CoV-2) polymerase chain reaction (PCR) test between 03/2020-07/2021 at the Vienna General Hospital were included. Patients were stratified for age: 18-39 vs. 40-69 vs. ≥70 years (y). Aspartate aminotransferase (AST), alanine-aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and total bilirubin (BIL) were recorded. RESULTS: 900 patients (18-39 years: 32.2%, 40-69 years: 39.7%, ≥70 years: 28.1%) were included. Number of comorbidities, median D-dimer and C-reactive protein increased with age. During COVID-19, AST/ALT and ALP/GGT levels significantly increased. Elevated hepatocellular transaminases (AST/ALT) and cholestasis parameters (ALP/GGT/BIL) were observed in 40.3% (n  = 262/650) and 45.0% (n  = 287/638) of patients respectively. Liver-related mortality was highest among patients with pre-existing decompensated liver disease (28.6%, p < .001). 1.7% of patients without pre-existing liver disease died of liver-related causes, that is consequences of hepatic dysfunction or acute liver failure. Importantly, COVID-19-associated liver injury (16.0%, p < .001), abnormal liver chemistries and liver-related mortality (6.5%, p < .001) were most frequent among 40-69 years old patients. Elevated AST and BIL after the first positive SARS-CoV-2 PCR independently predicted mortality in the overall cohort and in 40-69 years old patients. CONCLUSIONS: Almost half of the COVID-19 patients exhibit abnormal hepatocellular and cholestasis-related liver chemistries with 40-69 years old patients being at particularly high risk for COVID-19-related liver injury and liver-related mortality. Elevated AST and BIL after SARS-CoV-2 infection are independent predictors of mortality, especially in patients aged 40-69 years.

Static and dynamic forces in the incudostapedial joint gap.

Dynamic pressure at the tympanic membrane is transformed and subsequently transferred through the ossicular chain in the form of forces and moments. The forces are primarily transferred to the inner ear. They are transferred partly to the stapedial annular ligament which exhibits non-linear behavior and stiffens for larger static forces. In unventilated middle ears, static pressure is additionally transferred to the ossicles. The purpose of this study was to measure the force inside the ossicular chain as a physiological parameter. We determined the forces which act for dynamic sound transmission and for static load on the ossicular chain. The study is the first one which introduces these forces. The static forces have direct impact on clinically relevant questions for middle ear reconstructions with passive or active prosthesis. The dynamic forces have an impact on the development of middle ear sensors. Quasi-static forces in the incudostapedial joint (ISJ) gap were measured with two different sensor types in 17 temporal bones. The sensing elements, a single crystal piezo and a strain gauge element for validation, were bonded to a thin flexible titanium plate and encapsulated in a titanium housing to allow the acquisition of the applied force signal inside the ossicular chain. Dynamic forces were measured in 11 temporal bones with the piezo sensor. We measured a static force of 23 mN in the ISJ after sensor insertion. The mean force for dynamic physiological acoustic excitation from 250 Hz to 6 kHz was 26 µN/Pa. If the tympanic membrane is loaded with a static pressure, the static force in the ISJ increases up to 1 N for a maximum static pressure load scenario of 30 kPa.