18 F-Fluoride Imaging for Atherosclerosis Mohler, Emile R., MD; Alavi, Abass, MD; Wilensky, Robert L., MD
Journal of the American College of Cardiology,
2012, Volume:
60, Issue:
17
Journal Article
Objectives We performed a meta-analysis to evaluate the impact of pioglitazone in the prevention of in-stent restenosis (ISR) and need for revascularization after bare-metal stent (BMS) implantation. ...Background BMS use is associated with a significant incidence of restenosis. Pioglitazone, a thiazolidinedione (TZD), has been shown in small studies to be associated with decreased neointimal formation after BMS implantation. Methods The meta-analysis included randomized controlled trials that randomized patients undergoing BMS implantation into pioglitazone treatment in combination with standard treatment or standard treatment only. All randomized controlled trials followed patients for 6 months with baseline and follow-up angiographies. The ISR and revascularization rate were considered primary outcomes. Results We identified 6 eligible studies involving 373 patients (187 in the pioglitazone group and 186 in the control group). Use of pioglitazone was associated with decreased late loss, a larger minimal lumen diameter, and a lower percentage diameter stenosis (p < 0.01). The angiographic ISR rate was decreased with pioglitazone (p < 0.01), and patients who received pioglitazone were significantly less likely to undergo revascularization (p < 0.01). Intravascular ultrasound analysis also demonstrated decreased neointima formation in the pioglitazone group. Subgroup analysis showed significant reduction in ISR and need for revascularization for studies involving only diabetic patients, whereas analysis of the remaining studies demonstrated nonsignificant reduction. Conclusions This meta-analysis suggests that treatment with pioglitazone is effective in decreasing ISR and need for revascularization after BMS implantation in patients with diabetes. A randomized clinical trial evaluating the hypothesis that administration of pioglitazone reduces restenosis in diabetic patients after BMS implantation seems warranted.
The compact configuration of Phase II of the Murchison Widefield Array (MWA) consists of both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model and ...redundant interferometric calibration. The highly redundant hexagonal cores give improved power spectrum sensitivity. In this paper, we present the analysis of nearly 40 hours of data targeting one of the MWA's EoR fields observed in 2016. We use both improved analysis techniques presented in Barry et al. (2019) as well as several additional techniques developed for this work, including data quality control methods and interferometric calibration approaches. We show the EoR power spectrum limits at redshift 6.5, 6.8 and 7.1 based on our deep analysis on this 40-hour data set. These limits span a range in \(k\) space of \(0.18\) \(h\) \(\mathrm{Mpc^{-1}}\) \(<k<1.6\) \(h\) \(\mathrm{Mpc^{-1}}\), with a lowest measurement of \(\Delta^2\leqslant2.39\times 10^3\) \(\mathrm{mK}^2\) at \(k=0.59\) \(h\) \(\mathrm{Mpc^{-1}}\) and \(z=6.5\).
Although previous studies have demonstrated that Hispanic patients have a higher cardiovascular risk profile than Caucasians and present at a younger age for percutaneous coronary intervention (PCI), ...limited studies exist examining the outcomes of Hispanics after PCI and potential explanations for differences noted. Using patients from the National Heart, Lung, and Blood Institute Dynamic Registry waves 1 to 5 (1997 to 2006), demographic features, angiographic data, and 1-year outcomes of Hispanic patients (n = 542) versus Caucasian patients (n = 1,357) undergoing PCI were evaluated. Compared to Caucasians, Hispanic patients were younger and had more hypertension and diabetes mellitus, including more insulin-treated diabetes mellitus. Although mean lesion length was longer in Hispanics (15.4 vs 14.1 mm, p <0.001), there were no differences in the number of significant lesions or in the use of drug-eluting stents. At follow-up, Hispanics were more likely to report recent anginal symptoms but had a similar incidence of 1-year hospitalizations for angina. Adjusted 1-year hazard ratios for adverse events for Hispanics versus Caucasians revealed lower rates of coronary artery bypass graft surgery (hazard ratio 0.43, confidence interval 0.22 to 0.85, p = 0.02) and a trend toward lower rates of repeat revascularization (hazard ratio 0.76, confidence interval 0.57 to 1.03, p = 0.08). In conclusion, despite the presence of diabetes in almost 50% of Hispanic patients and longer lesions than in Caucasians, Hispanic patients were less likely to undergo coronary artery bypass graft surgery 1 year after PCI and had a trend toward lower rates of repeat revascularization.
We compute the spherically-averaged power spectrum from four seasons of data obtained for the Epoch of Reionisation (EoR) project observed with the Murchison Widefield Array (MWA). We measure the EoR ...power spectrum over \(k= 0.07-3.0~h\)Mpc\(^{-1}\) at redshifts \(z=6.5-8.7\). The largest aggregation of 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement of (43~mK)\(^2\) = 1.8\(\times\)10\(^3\) mK\(^2\) at \(k\)=0.14~\(h\)Mpc\(^{-1}\) and \(z=6.5\) (2\(\sigma\) thermal noise plus sample variance). Using the Real-Time System to calibrate and the CHIPS pipeline to estimate power spectra, we select the best observations from the central five pointings within the 2013--2016 observing seasons, observing three independent fields and in two frequency bands. This yields 13,591 2-minute snapshots (453 hours), based on a quality assurance metric that measures ionospheric activity. We perform another cut to remove poorly-calibrated data, based on power in the foreground-dominated and EoR-dominated regions of the two-dimensional power spectrum, reducing the set to 12,569 observations (419 hours). These data are processed in groups of 20 observations, to retain the capacity to identify poor data, and used to analyse the evolution and structure of the data over field, frequency, and data quality. We subsequently choose the cleanest 8,935 observations (298 hours of data) to form integrated power spectra over the different fields, pointings and redshift ranges.
Measurements of 21 cm Epoch of Reionization (EoR) structure are subject to systematics originating from both the analysis and the observation conditions. Using 2013 data from the Murchison Widefield ...Array (MWA), we show the importance of mitigating both sources of contamination. A direct comparison between results from Beardsley et al. 2016 and our updated analysis demonstrates new precision techniques, lowering analysis systematics by a factor of 2.8 in power. We then further lower systematics by excising observations contaminated by ultra-faint RFI, reducing by an additional factor of 3.8 in power for the zenith pointing. With this enhanced analysis precision and newly developed RFI mitigation, we calculate a noise-dominated upper limit on the EoR structure of \(\Delta^2 \leq 3.9 \times 10^3\) mK\(^2\) at \(k=0.20\) \(\textit{h}\) Mpc\(^{-1}\) and \(z=7\) using 21 hr of data, improving previous MWA limits by almost an order of magnitude.
We explore methods for robust estimation of the 21 cm signal from the Epoch of Reionisation (EoR). A Kernel Density Estimator (KDE) is introduced for measuring the spatial temperature fluctuation ...power spectrum from the EoR. The KDE estimates the underlying probability distribution function of fluctuations as a function of spatial scale, and contains different systematic biases and errors to the typical approach to estimating the fluctuation power spectrum. Extraction of histograms of visibilities allows moments analysis to be used to discriminate foregrounds from 21 cm signal and thermal noise. We use the information available in the histograms, along with the statistical dis-similarity of foregrounds from two independent observing fields, to robustly separate foregrounds from cosmological signal, while making no assumptions about the Gaussianity of the signal. Using two independent observing fields to robustly discriminate signal from foregrounds is crucial for the analysis presented in this paper. We apply the techniques to 13 hours of Murchison Widefield Array (MWA) EoR data over two observing fields. We compare the output to that obtained with a comparative power spectrum estimation method, and demonstrate the reduced foreground contamination using this approach. Using the second moment obtained directly from the KDE distribution functions yields a factor of 2-3 improvement in power for k < 0.3hMpc^{-1} compared with a matched delay space power estimator, while weighting data by additional statistics does not offer significant improvement beyond that available for thermal noise-only weights.
We apply two methods to estimate the 21~cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II ...compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly-spaced triangles of antenna tiles, as well as an estimate based on data gridded to the \(uv\)-plane. The direct and gridded bispectrum estimators are applied to 21 hours of high-band (167--197~MHz; \(z\)=6.2--7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 hours, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21~cm bispectrum may be accessible in less time than the 21~cm power spectrum for some wave modes, with detections in hundreds of hours.
The SIRIUS study was a double-blinded, randomized trial of the sirolimus-eluting stent (SES) to evaluate its effect on the rate of restenosis. The present report is a retrospective analysis of short- ...and long-term outcomes of SESs compared with bare metal stents (BMSs) in a subgroup of patients with unstable angina enrolled in the trial. Of 1,058 patients randomized in SIRIUS, 533 (50.4%) had unstable angina pectoris and 490 had stable angina. In the unstable angina group, patients treated with SESs and BMSs had similar clinical and angiographic characteristics. The stenting procedure was highly successful in the 2 groups (95.9% and 97.4%, respectively) with similar immediate angiographic results and short-term (in-hospital) clinical event rates. At 1-year follow-up, compared with BMSs, patients with unstable angina treated with SESs had significantly lower rates of target lesion revascularization (5.5% vs 22.3%, p <0.0001), target vessel failure (10.9% vs 26.3%, p <0.0001), and major adverse cardiac events (8.4% vs 24.8%, p <0.0001). Stent thrombosis was a rare event, with only 1 patient (0.4%) in each group during the first 30 days. Late thrombosis occurred in 2 patients (0.7%) in the BMS group but in none of the SES group. In conclusion, in the higher risk subgroup of patients with unstable angina, SESs are as safe as BMSs in decreasing restenosis and the need for repeat revascularization. This is reflected by a significant decrease in major adverse cardiac events and target vessel failure. Patients with unstable angina undergoing percutaneous coronary intervention who meet the entry criteria of the SIRIUS study should be preferentially treated with SESs.
The locations of Ly-\(\alpha\) emitting galaxies (LAEs) at the end of the Epoch of Reionisation (EoR) are expected to correlate with regions of ionised hydrogen, traced by the redshifted 21~cm ...hyperfine line. Mapping the neutral hydrogen around regions with detected and localised LAEs offers an avenue to constrain the brightness temperature of the Universe within the EoR by providing an expectation for the spatial distribution of the gas, thereby providing prior information unavailable to power spectrum measurements. We use a test set of 12 hours of observations from the Murchison Widefield Array (MWA) in extended array configuration, to constrain the neutral hydrogen signature of 58 LAEs, detected with the Subaru Hypersuprime Cam in the \textit{Silverrush} survey, centred on \(z\)=6.58. We assume that detectable emitters reside in the centre of ionised HII bubbles during the end of reionization, and predict the redshifted neutral hydrogen signal corresponding to the remaining neutral regions using a set of different ionised bubble radii. A prewhitening matched filter detector is introduced to assess detectability. We demonstrate the ability to detect, or place limits upon, the amplitude of brightness temperature fluctuations, and the characteristic HII bubble size. With our limited data, we constrain the brightness temperature of neutral hydrogen to \(\Delta{\rm T}_B<\)30 mK (\(<\)200 mK) at 95% (99%) confidence for lognormally-distributed bubbles of radii, \(R_B =\) 15\(\pm\)2\(h^{-1}\)cMpc.
PDF
