Procedural recommendations of cardiac PET/CT imaging:standardization in inflammatory-, infective-, infiltrative-, and innervation (4Is)-related cardiovascular diseases: a joint collaboration of the EACVI and the EANM

With this document, we provide a standard for PET/(diagnostic) CT imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is). This standard should be applied in clinical practice and integrated in clinical (multicenter) trials for optimal procedural standardization. A major focus is put on procedures using [18F]FDG, but 4Is PET radiopharmaceuticals beyond [18F]FDG are also described in this document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicenter trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Finally, PET/MR applications in 4Is cardiovascular diseases are also briefly described. Diagnosis and management of 4Is-related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/MR, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.</p

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation (4Is)-related cardiovascular diseases: a joint collaboration of the EACVI and the EANM

With this document, we provide a standard for PET/(diagnostic) CT imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is). This standard should be applied in clinical practice and integrated in clinical (multicenter) trials for optimal procedural standardization. A major focus is put on procedures using [18F]FDG, but 4Is PET radiopharmaceuticals beyond [18F]FDG are also described in this document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicenter trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Finally, PET/MR applications in 4Is cardiovascular diseases are also briefly described. Diagnosis and management of 4Is-related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/MR, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.</p

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation- (4Is) related cardiovascular diseases: a joint collaboration of the EACVI and the EANM: summary

With this summarized document we share the standard for positron emission tomography (PET)/(diagnostic)computed tomography (CT) imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is) as recently published in the European Journal of Nuclear Medicine and Molecular Imaging. This standard should be applied in clinical practice and integrated in clinical (multicentre) trials for optimal standardization of the procedurals and interpretations. A major focus is put on procedures using [18F]-2-fluoro-2-deoxyglucose ([18F]FDG), but 4Is PET radiopharmaceuticals beyond [18F]FDG are also described in this summarized document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicentre trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Diagnosis and management of 4Is related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/magnetic resonance, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.</p

Review of Environmental Monitoring by Means of Radio Waves in the Polar Regions: From Atmosphere to Geospace

The Antarctic and Arctic regions are Earth's open windows to outer space. They provide unique opportunities for investigating the troposphere–thermosphere–ionosphere–plasmasphere system at high latitudes, which is not as well understood as the mid- and low-latitude regions mainly due to the paucity of experimental observations. In addition, different neutral and ionised atmospheric layers at high latitudes are much more variable compared to lower latitudes, and their variability is due to mechanisms not yet fully understood. Fortunately, in this new millennium the observing infrastructure in Antarctica and the Arctic has been growing, thus providing scientists with new opportunities to advance our knowledge on the polar atmosphere and geospace. This review shows that it is of paramount importance to perform integrated, multi-disciplinary research, making use of long-term multi-instrument observations combined with ad hoc measurement campaigns to improve our capability of investigating atmospheric dynamics in the polar regions from the troposphere up to the plasmasphere, as well as the coupling between atmospheric layers. Starting from the state of the art of understanding the polar atmosphere, our survey outlines the roadmap for enhancing scientific investigation of its physical mechanisms and dynamics through the full exploitation of the available infrastructures for radio-based environmental monitoring

Ionospheric D-region studies by means of active heating experiments and modelling

Abstract Powerful radio waves can heat an electron gas via collisions between free electrons and neutral particles. Since the discovery of the Luxembourg effect in 1934, this effect is known to take place in the D-region ionosphere. According to theoretical models, the EISCAT Heating facility is capable of increasing the electron temperature by a factor of 5–10 in the D region, depending mostly on the electron density profile. Various indirect evidence for the existence of the D-region heating effect has been available, including successful modification of ionospheric conductivities and mesospheric chemistry. However, an experimental quantification of the electron temperature at its maximum in the heated D-region ionosphere has been missing. In particular, incoherent scatter (IS) radars should be able to observe directly plasma parameters, such as the electron temperature, although the heated D-region ionosphere is not a trivial target because of low electron density, and hence, small signal-to-noise ratio (SNR). In this thesis, Papers I and III present unique estimates for heated D-region electron temperatures based on IS measurements. It turned out that the theoretical predictions of the electron temperature generally agree with the few existing observations, at least at the altitudes of the maximum heating effect. Quite in contrast, when the D-region heating effect on the cosmic radio noise absorption was verified for the first time by the statistical data analysis presented in Paper II, the absorption enhancements due to heating were found to be an order of magnitude smaller than model results. The reason for this discrepancy remains still as open question, although one possible explanation is provided by the electron-temperature dependent ion chemistry, which was not taken into account in the modelling. The significance of the heating-induced ion chemistry effect in the D-region was investigated in Paper IV. There the heating-induced negative ion formation is proposed as a potential explanation for the observed modulation of Polar Mesosphere Winter Echo (PMWE) power

On the determination of ionospheric electron density profiles using multi-frequency riometry

Abstract Radio wave absorption in the ionosphere is a function of electron density, collision frequency, radio wave polarisation, magnetic field and radio wave frequency. Several studies have used multi-frequency measurements of cosmic radio noise absorption to determine electron density profiles. Using the framework of statistical inverse problems, we investigated if an electron density altitude profile can be determined by using multi-frequency, dual-polarisation measurements. It was found that the altitude profile cannot be uniquely determined from a “complete” measurement of radio wave absorption for all frequencies and two polarisation modes. This implies that accurate electron density profile measurements cannot be ascertained using multi-frequency riometer data alone and that the reconstruction requires a strong additional a priori assumption of the electron density profile, such as a parameterised model for the ionisation source. Nevertheless, the spectral index of the absorption could be used to determine if there is a significant component of hard precipitation that ionises the lower part of the D region, but it is not possible to infer the altitude distribution uniquely with this technique alone

Chemical response of the upper atmosphere due to lightning-induced electron precipitation

Abstract Terrestrial lightning frequently serves as a loss mechanism for energetic electrons in the Van Allen radiation belts, leading to lightning-induced electron precipitation (LEP). Regardless of the specific causes, energetic electron precipitation from the radiation belts in general has a significant influence on the ozone concentration in the stratosphere and mesosphere. The atmospheric chemical effects induced by LEP have been previously investigated using subionospheric VLF measurements at Faraday station, Antarctica (65.25°S, 64.27°W, L = 2.45). However, there exist large variations in the precipitation flux, ionization production, and occurrence rate of LEP events depending on the peak current of the parent lightning discharge, as well as the season, location, and intensity of the thunderstorm activity. These uncertainties motivate us to revisit the calculation of atmospheric chemical changes produced by LEP. In this study, we combine a well-validated LEP model and first-principles atmospheric chemical simulation, and investigate three intense storms in the year of 2013, 2015, and 2017 at the magnetic latitude of 50.9°, 32.1°, and 35.7°. Modeling results show that the LEP events in these storms can cumulatively drive significant changes in the NOₓ, HOₓ, and Oₓ concentration in the mesosphere. These changes are as high as ~156%, ~66%, and -5% at 75–85 km altitude, respectively, and comparable to the effects typically induced by other types of radiation belt electron precipitation events. Considering the high occurrence rate of thunderstorms around the globe, the long-term global chemical effects produced by LEP events need to be properly quantified

Atmospheric effects of a relativistic electron beam injected from above:chemistry, electrodynamics, and radio scattering

Abstract We present numerical simulations and analysis of atmospheric effects of a beam of 1 MeV electrons precipitating in the upper atmosphere from above. Beam parameters of 100 J or 1 kJ injected in 100 ms or 1 s were chosen to reflect the current design requirements for a realistic mission. We calculate ionization signatures and optical emissions in the atmosphere, and estimate the detectability of optical signatures using photometers and cameras on the ground. Results show that both instruments should be able to detect the beam spot. Chemical simulations show that the production of odd nitrogen and odd hydrogen are minimal. We use electrostatic field simulations to show that the beam-induced electron density column can enhance thunderstorm electric fields at high altitudes enough to facilitate sprite triggering. Finally, we calculate signatures that would be observed by incoherent scatter radar (ISR) and subionospheric VLF remote sensing techniques, although the latter is hindered by the limitations of 2D simulations

On the effects of bremsstrahlung radiation during energetic electron precipitation

Abstract Precipitation of energetic particles into the Earth’s atmosphere can significantly change the properties, dynamics, as well as the chemical composition of the upper and middle atmosphere. In this paper, using Monte Carlo models, we simulate, from first principles, the interaction of monoenergetic beams of precipitating electrons with the atmosphere, with particular emphasis on the process of bremsstrahlung radiation and its resultant ionization production and atmospheric effects. The pitch angle dependence of the ionization rate profile has been quantified: the altitude of peak ionization rate depends on the pitch angle by a few kilometers. We also demonstrate that the transport of precipitating electron energy in the form of bremsstrahlung photons leads to ionization at altitudes significantly lower than the direct impact ionization, as low as ∼20 km for 1 MeV precipitating electrons. Moreover, chemical modeling results suggest that the chemical effects in the atmosphere due to bremsstrahlung‐induced ionization production during energetic electron precipitation are likely insignificant