To investigate the performance of low-dose, dual-source computed tomography (DSCT) coronary angiography in the step-and-shoot (SAS) mode for the diagnosis of significant coronary artery stenoses in ...comparison with conventional coronary angiography (CCA).
Prospective, single-centre study conducted in a referral centre enrolling 120 patients (71 men, mean (SD) age 68 (9) years, mean (SD) body mass index 26.2 (3.2) kg/m2). All study participants underwent DSCT in the SAS mode and CCA within 14 days. Twenty-seven patients were given intravenous beta blockers for heart rate reduction before CT. Patients were excluded if a target heart rate <or=70 bpm could not be achieved by beta blockers or when the patients were in non-sinus rhythm. Two blinded readers independently evaluated coronary artery segments for assessability and for the presence of significant (>50%) stenoses. Sensitivity, specificity, negative (NPV) and positive predictive values (PPV) were determined, with CCA being the standard of reference. Radiation dose values were calculated.
DSCT coronary angiography in the SAS mode was successfully performed in all 120 patients. Mean (SD) heart rate during scanning was 59 (6) bpm (range 44-69). 1773/1803 coronary segments (98%) were depicted with a diagnostic image quality in 109/120 patients (91%). The overall patient-based sensitivity, specificity, PPV and NPV for the diagnosis of significant stenoses were 100%, 93%, 94% and 100%, respectively. The mean (SD) effective dose of the CT protocol was 2.5 (0.8) mSv (range 1.2-4.4).
DSCT coronary angiography in the SAS mode allows, in selected patients with a regular heart rate, the accurate diagnosis of significant coronary stenoses at a low radiation dose.
Singly charged clusters C+A– n C+ or C+A– n A– of two salts C+A– are produced by electrospray ionization of alcohol solutions of the ionic liquids 1-ethyl-3-methylimidazolium ...tris(pentafluoroethyl)trifluorophosphate (EMI-FAP) and 1,2-dimethyl-3-propylimidazolium-methide (DMPI-Me). The rate of neutral pair evaporation into C+A– + C+A– n−1C+ or C+A– n−1A– is studied in atmospheric pressure as a function of temperature T for the positive trimer ion (n = 2) of DMPI-Me and the negative trimer ion of EMI-FAP. The trimer is separated from all other electrosprayed ions in a first differential mobility analyzer (DMA1) and then transferred through a cooled tube to a second DMA whose drift gas is kept at a controlled temperature (25 °C < T < 100 °C). Singular characteristics of the DMA are a residence time τ of ∼0.1 to 1 ms, with essentially uniform temperature and τ. The decomposition occurring within DMA2 results in a complex mobility spectrum associated with dimer product ions, with apparent mobilities intermediate between those of the dimer and the trimer, depending on the product of the reaction rate k and τ. A theoretical expression yielding k from the shape of the collected mobility spectrum is obtained by accounting for the deterministic reactive, convective, and diffusive evolutions of the parent and product ions within DMA2. Observed and predicted mobility spectra agree well, yielding the reaction rate k with little ambiguity. Activation energies near 1 eV are determined for both trimer ions. Paradoxically, the evaporation process substantially heats up the cluster ion product. The theory developed enables measuring decay times much smaller and much larger than the residence time in the DMA.
Abstract
We analyze the generation of spin-squeezed states via coupling of three-level atoms to an optical cavity and continuous quantum measurement of the transmitted cavity field in order to ...monitor the evolution of the atomic ensemble. Using analytical treatment and microscopic simulations of the dynamics, we show that one can achieve significant spin squeezing, favorably scaling with the number of atoms
N
. However, contrary to some previous literature, we clarify that it is not possible to obtain Heisenberg scaling without the continuous feedback that is proposed in optimal approaches. In fact, in the adiabatic cavity removal approximation and large
N
limit, we find the scaling behavior
N
−
2
/
3
for spin squeezing and
N
−
1
/
3
for the corresponding protocol duration. These results can be obtained only by considering the curvature of the Bloch sphere, since linearizing the collective spin operators tangentially to its equator yields inaccurate predictions. With full simulations, we characterize how spin-squeezing generation depends on the system parameters and departs from the bad cavity regime, by gradually mixing with cavity-filling dynamics until metrological advantage is lost. Finally, we discuss the relevance of this spin-squeezing protocol to state-of-the-art optical clocks.
•Description of the state-of-the-art of the theoretical tools for multiparameter quantum estimation.•Perspective on theoretical and fundamental open questions in multiparameter quantum ...estimation.•Description of state-of-the-art in (multiparameter) quantum imaging: from superresolution to phase-imaging.•Perspective on future applications of multiparameter quantum estimation.
The interest in a system often resides in the interplay among different parameters governing its evolution. It is thus often required to access many of them at once for a complete description. Assessing how quantum enhancement in such multiparameter estimation can be achieved depends on understanding the many subtleties that come into play: establishing solid foundations is key to delivering future technology for this task. In this article we discuss the state of the art of quantum multiparameter estimation, with a particular emphasis on its theoretical tools, on application to imaging problems, and on the possible avenues towards the next developments.
Assessment of cardiac output (CO) by the FloTrac/Vigileo system may offer a less invasive means of determining the CO than either the pulmonary artery catheter (PAC) or the PiCCOplus system. The aim ...of this study was to compare CO measurements made using the FloTrac/Vigileo system with upgraded software (FCO, Edwards Lifesciences, Irvine CA, USA), the PiCCOplus system (PCO, Pulsion Medical Systems, Munich, Germany) and continuous CO monitoring using a PAC (CCO; Vigilance monitoring, Edwards Lifesciences, Irvine CA, USA) with intermittent pulmonary artery thermodilution (ICO). The study was conducted in patients undergoing elective cardiac surgery.
Thirty-one patients with preserved left ventricular function were enrolled. CCO, FCO, and PCO were recorded in the perioperative period at six predefined time points after achieving stable haemodynamic conditions; ICO was determined from the mean of three bolus injections. Bland-Altman analysis was used to compare CCO, FCO, and PCO with ICO.
Bland-Altman analysis revealed a comparable mean bias and limits of agreement for all tested continuous CO monitoring devices using ICO as reference method. Agreement for all devices decreased in the postoperative period.
The performance of the FloTrac/Vigileo system, the PiCCOplus, and the Vigilance CCO monitoring for CO measurement were comparable when tested against intermittent thermodilution in patients undergoing elective cardiac surgery.
Aims To prospectively investigate the diagnostic accuracy of dual-source computed tomography coronary angiography (CTCA) to diagnose coronary stenoses in relation to body mass index (BMI), Agatston ...score (AS), and heart rate (HR) as compared with catheter coronary angiography (CCA). Methods and results Hundred and fifty consecutive patients (47 female, mean age 62.9 ± 12.1 years) underwent dual-source CTCA without HR control. Patients were divided into subgroups depending on the median of their BMI (26.0 kg/m2), AS (194), and HR (66 b.p.m.). CCA was considered the standard of reference. Mean BMI was 26.5 ± 4.2 kg/m2 (range 18.3–39.1 kg/m2), mean AS was 309 ± 408 (range 0–4387), and HR was 68.5 ± 12.6 b.p.m. (range 35–102 b.p.m.). Diagnostic image quality was found in 98.1% of all segments (2020/2059). Considering not-evaluative segments at CTCA as false-positive, overall per-patient sensitivity, specificity, positive, and negative predictive value were 96.6%, 86.8%, 82.6%, and 97.5%, respectively. High HR did not deteriorate diagnostic accuracy of CTCA. High BMI and AS were associated with a decrease in per-patient specificity to 84.1% and 77.8%, respectively, while sensitivity and negative predictive value remained high. Conclusion Dual-source CTCA provides high diagnostic accuracy irrespective of the HR and serves as a modality to rule-out coronary artery stenoses even in patients with high BMI and AS.
Background: Staphylococcus lugdunensis endocarditis has been associated with an aggressive course. The aim of this study was to determine factors associated with the development of endocarditis in ...patients with S. lugdunensis bacteremia. Methods: A retrospective analysis of all patients with S. lugdunensis bacteremia in three tertiary care centers in Switzerland was performed. Data regarding medical history, symptoms, and susceptibility of S. lugdunensis isolates were collected. Our results were reviewed in the context of the current literature. Results: A total of 28 patients with S. lugdunensis bacteremia were identified. Of the 13 patients with endocarditis, all were community acquired. Cardiac surgery was performed in 85% of these patients; mortality was 23%, reflecting the aggressive course of this disease. In contrast, in the 15 patients without endocarditis, no complications associated with S. lugdunensis bacteremia were observed. In 73%, a probable source was identified in the form of a venous catheter or other foreign device. Only three of these episodes were community acquired. No difference was observed in susceptibility of the S. lugdunensis isolates to penicillin, which was 77% in endocarditis isolates, and 87% in isolates of bacteremia without endocarditis, respectively. Conclusion: S. lugdunensis bacteremia is associated with endocarditis in up to 50% of patients. Every patient with community-acquired S. lugdunensis bacteremia should be carefully examined for signs of endocarditis. Once S. lugdunensis endocarditis is diagnosed, close monitoring is essential and surgical treatment should be considered early. In the nosocomial setting, endocarditis is far less frequent, and S. lugdunensis bacteremia is usually associated with a catheter or other foreign materials.
Optomechanical systems are promising platforms for controlled light-matter interactions. They are capable of providing several fundamental and practical novel features when the mechanical oscillator ...is cooled down to nearly reach its ground state. In this framework, measuring the effective temperature of the oscillator is perhaps the most relevant step in the characterization of those systems. In conventional schemes, the cavity is driven strongly, and the overall system is well-described by a linear (Gaussian preserving) Hamiltonian. Here, we depart from this regime by considering an undriven optomechanical system via non-Gaussian radiation-pressure interaction. To measure the temperature of the mechanical oscillator, initially in a thermal state, we use light as a probe to coherently interact with it and create an entangled state. We show that the optical probe gets a nonlinear phase, resulting from the non-Gaussian interaction, and undergoes an incoherent phase diffusion process. To efficiently infer the temperature from the entangled light-matter state, we propose using a nonlinear Kerr medium before a homodyne detector. Remarkably, placing the Kerr medium enhances the precision to nearly saturate the ultimate quantum bound given by the quantum Fisher information. Furthermore, it also simplifies the thermometry procedure as it makes the choice of the homodyne local phase independent of the temperature.
Hybrid optomechanical systems are emerging as a fruitful architecture for quantum technologies. Hence determining the relevant atom-light and light-mechanics couplings is an essential task in such ...systems. The fingerprint of these couplings is left in the global state of the system during nonequilibrium dynamics. However, in practice, performing measurements on the entire system is not feasible, and thus one has to rely on partial access to one of the subsystems, namely, the atom, the light, or the mechanics. Here we perform a comprehensive analysis to determine the optimal subsystem for probing the couplings. We find that if the light-mechanics coupling is known or irrelevant, depending on the range of the qubit-light coupling, then the optimal subsystem can be either the light or the qubit. In other scenarios, e.g., simultaneous estimation of the couplings, the light is usually the optimal subsystem. This can be explained as light is the mediator between the other two subsystems. Finally, we show that the widely used homodyne detection can extract a fair fraction of the information about the couplings from the light degrees of freedom.
End-diastolic volume indices determined by transpulmonary thermodilution and pulmonary artery thermodilution may give a better estimate of left ventricular preload than pulmonary capillary wedge ...pressure monitoring. The aim of this study was to compare volume preload monitoring using the two different thermodilution techniques with left ventricular preload assessment by transoesophageal echocardiography (TOE).
Twenty patients undergoing elective cardiac surgery with preserved left–right ventricular function were studied after induction of anaesthesia. Conventional haemodynamic variables, global end-diastolic volume index using the pulse contour cardiac output (PiCCO) system (GEDVIPiCCO), continuous end-diastolic volume index (CEDVIPAC) measured by a modified pulmonary artery catheter (PAC), left ventricular end-diastolic area index (LVEDAI) using TOE and stroke volume indices (SVI) were recorded before and 20 and 40 min after fluid replacement therapy. Analysis of variance (Bonferroni–Dunn), Bland–Altman analysis and linear regression were performed.
GEDVIPiCCO, CEDVIPAC, LVEDAI and SVIPiCCO/PAC increased significantly after fluid load (P<0.05). An increase >10% for GEDVIPiCCO and LVEDAI was observed in 85% and 90% of the patients compared with 45% for CEDVIPAC. Mean bias (2 sd) between percentage changes (Δ) in GEDVIPiCCO and ΔLVEDAI was −3.2 (17.6)% and between ΔCEDVIPAC and ΔLVEDAI −8.7 (30.0)%. The correlation coefficient (r2) for ΔGEDVIPiCCOvs ΔLVEDAI was 0.658 and for ΔCEDVIPACvs ΔLVEDAI 0.161. The relationship between ΔGEDVIPiCCO and ΔSVIPiCCO was stronger (r2=0.576) than that between ΔCEDVIPAC and ΔSVIPAC (r2=0.267).
GEDVI assessed by the PiCCO system gives a better reflection of echocardiographic changes in left ventricular preload, in response to fluid replacement therapy, than CEDVI measured by a modified PAC.
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