(1) Background: Large cohort studies of patients with COVID-19 treated with remdesivir have reported improved clinical outcomes, but data on older patients are scarce. Objective: This work aims to ...assess the potential benefit of remdesivir in unvaccinated very old patients hospitalized with COVID-19; (2) Methods: This is a retrospective analysis of patients ≥ 80 years hospitalized in Spain between 15 July and 31 December 2020 (SEMI-COVID-19 Registry). Differences in 30-day all-cause mortality were adjusted using a multivariable regression analysis. (3) Results: Of the 4331 patients admitted, 1312 (30.3%) were ≥80 years. Very old patients treated with remdesivir (n: 140, 10.7%) had a lower mortality rate than those not treated with remdesivir (OR (95% CI): 0.45 (0.29−0.69)). After multivariable adjustment by age, sex, and variables associated with lower mortality (place of COVID-19 acquisition; degree of dependence; comorbidities; dementia; duration of symptoms; admission qSOFA; chest X-ray; D-dimer; and treatment with corticosteroids, tocilizumab, beta-lactams, macrolides, and high-flow nasal canula oxygen), the use of remdesivir remained associated with a lower 30-day all-cause mortality rate (adjusted OR (95% CI): 0.40 (0.22−0.61) (p < 0.001)). (4) Conclusions: Remdesivir may reduce mortality in very old patients hospitalized with COVID-19.
It is unclear to which extent the higher mortality associated with hypertension in the coronavirus disease (COVID-19) is due to its increased prevalence among older patients or to specific ...mechanisms. Cross-sectional, observational, retrospective multicenter study, analyzing 12226 patients who required hospital admission in 150 Spanish centers included in the nationwide SEMI-COVID-19 Network. We compared the clinical characteristics of survivors versus non-survivors. The mean age of the study population was 67.5 ± 16.1 years, 42.6% were women. Overall, 2630 (21.5%) subjects died. The most common comorbidity was hypertension (50.9%) followed by diabetes (19.1%), and atrial fibrillation (11.2%). Multivariate analysis showed that after adjusting for gender (males, OR: 1.5, p = 0.0001), age tertiles (second and third tertiles, OR: 2.0 and 4.7, p = 0.0001), and Charlson Comorbidity Index scores (second and third tertiles, OR: 4.7 and 8.1, p = 0.0001), hypertension was significantly predictive of all-cause mortality when this comorbidity was treated with angiotensin-converting enzyme inhibitors (ACEIs) (OR: 1.6, p = 0.002) or other than renin-angiotensin-aldosterone blockers (OR: 1.3, p = 0.001) or angiotensin II receptor blockers (ARBs) (OR: 1.2, p = 0.035). The preexisting condition of hypertension had an independent prognostic value for all-cause mortality in patients with COVID-19 who required hospitalization. ARBs showed a lower risk of lethality in hypertensive patients than other antihypertensive drugs.
Purpose
The last decades have seen the consolidation of the cone‐beam CT (CBCT) technology, which is nowadays widely used for different applications such as micro‐CT for small animals, mammography, ...dentistry, or surgical procedures. Some CBCT systems may suffer mechanical strains due to the heavy load of the x‐ray tube. This fact, together with tolerances in the manufacturing process, lead to different types of undesirable effects in the reconstructed image unless they are properly accounted for during the reconstruction. To obtain good quality images, it is necessary to have a complete characterization of the system geometry including the angular position of the gantry, the source–object and detector–object distances, and the position and pose of the detector. These parameters can be obtained through a calibration process done periodically, depending on the stability of the system geometry. To the best of our knowledge, there are no comprehensive works studying the effect of inaccuracies in the geometrical calibration of CBCT systems in a systematic and quantitative way. In this work, we describe the effects of detector misalignments (linear shifts, rotation, and inclinations) on the image and define their tolerance as the maximum error that keeps the image free from artifacts.
Methods
We used simulations of four phantoms including systematic and random misalignments. Reconstructions of these data with and without errors were compared to identify the artifacts introduced in the reconstructed image and the tolerance to miscalibration deemed to provide acceptable image quality.
Results
Visual assessment provided an easy guideline to identify the sources of error by visual inspection of the artifactual images. Systematic errors result in blurring, shape distortion and/or reduction of the axial field of view while random errors produce streaks and blurring in all cases, with a tolerance which is more than twice that of systematic errors. The tolerance corresponding to errors in position of the detector along the tangential direction, that is, skew (<0.2°) and horizontal shift (<0.4 mm), is tighter than the tolerance to those errors affecting the position along the longitudinal direction or the magnification, that is, vertical shift (<2 mm), roll (<1.5°), tilt (<2°), and SDD (<3 mm).
Conclusion
We present a comprehensive study, based on realistic simulations, of the effects on the reconstructed image quality of errors in the geometrical characterization of a CBCT system and define their tolerance. These results could be used to guide the design of new systems, establishing the mechanical precision that must be achieved, and to help in the definition of an optimal geometrical calibration process. Also, the thorough visual assessment may be valuable to identify the most predominant sources of error based on the effects shown in the reconstructed image.
The aortic arch repair in the neonatal period is a complex procedure with significant morbidity. We define a useful double-perfusion technique and its effect on the function of abdominal organs in ...the postoperative course.
Nine patients with double perfusion (Group 1) were compared with 14 patients with antegrade cerebral perfusion (Group 2). The objective was to discern the incidence of postoperative acute kidney injury and impaired hepatic function, as well as tissue perfusion and myocardial function parameters. Mechanical ventilation time, postoperative length of stay and 30-day mortality were measured. We excluded patients with extracorporeal membrane oxygenation, early mortality (<72 h) and preoperative renal or hepatic insufficiency.
Nine (39%) patients developed postoperative acute kidney injury, with 22% (n = 2) in Group 1 and 50% (n = 7) in Group 2 (P = 0.183). A higher urine output was observed during the first 24 h for Group 1 (P = 0.032). Eleven patients developed impaired hepatic function in the immediate postoperative period: 2 (18.2%) in Group 1 and 9 (81.8%) in Group 2 (P = 0.04). The international normalized ratio (P = 0.006-0.031) and prothrombin time (P = 0.007-P = 0.016) were significantly lower in the double-perfusion group during the first 72 h. Significant difference was observed in lactate levels in the first 72 h (P = 0.001-0.009). There was no postoperative mortality in either group.
Selective visceral perfusion is a safe procedure that provides a better urine output, hepatic function and tissue perfusion. This technique allows for the repair of complex aortic arch anomalies in neonates without deep hypothermic circulatory arrest.
Objective
Dual energy radiography (DER) makes it possible to obtain separate images for soft‐tissue and bony structures (tissue maps) based on the acquisition of two radiographs at different source ...peak‐kilovoltage values. Current DER studies are based on the weighted subtraction method, which requires either manual tuning or the use of precomputed tables, or on decomposition methods, which make use of a calibration to model soft‐tissue and bone components. In this study, we examined in depth the optimum method to perform this calibration.
Methods
We used simulations to optimize the calibration protocol and evaluated the effect of the material and size of a calibration phantom composed of two wedges and its positioning in the system. Evaluated materials were water, PMMA and A‐150 as soft‐tissue equivalent, and Teflon, B‐100 and aluminum as bone equivalent, with sizes from 5 to 30 cm. Each material combination was compared with an ideal phantom composed of soft tissue and bone. Our simulation results enabled us to propose four designs that were tested with the NOVA FA X‐ray system with a realistic thorax phantom.
Results
Calibration based on a very simple and inexpensive phantom with no strict requirements in its placement results in appropriate separation of the spine (a common focus in densitometry studies) and the identification of nodules as small as 6 mm, which have been reported to have a low rate of detection in radiography.
Conclusion
The proposed method is completely automatic, avoiding the need for a radiology technician with expert knowledge of the protocol, as is the case in densitometry exams. The method provides real mass thickness values, enabling quantitative planar studies instead of relative comparisons.
The availability of digital X-ray detectors, together with advances in reconstruction algorithms, creates an opportunity for bringing 3D capabilities to conventional radiology systems. The downside ...is that reconstruction algorithms for non-standard acquisition protocols are generally based on iterative approaches that involve a high computational burden. The development of new flexible X-ray systems could benefit from computer simulations, which may enable performance to be checked before expensive real systems are implemented. The development of simulation/reconstruction algorithms in this context poses three main difficulties. First, the algorithms deal with large data volumes and are computationally expensive, thus leading to the need for hardware and software optimizations. Second, these optimizations are limited by the high flexibility required to explore new scanning geometries, including fully configurable positioning of source and detector elements. And third, the evolution of the various hardware setups increases the effort required for maintaining and adapting the implementations to current and future programming models. Previous works lack support for completely flexible geometries and/or compatibility with multiple programming models and platforms. In this paper, we present FUX-Sim, a novel X-ray simulation/reconstruction framework that was designed to be flexible and fast. Optimized implementation for different families of GPUs (CUDA and OpenCL) and multi-core CPUs was achieved thanks to a modularized approach based on a layered architecture and parallel implementation of the algorithms for both architectures. A detailed performance evaluation demonstrates that for different system configurations and hardware platforms, FUX-Sim maximizes performance with the CUDA programming model (5 times faster than other state-of-the-art implementations). Furthermore, the CPU and OpenCL programming models allow FUX-Sim to be executed over a wide range of hardware platforms.
Solid organ transplantation (SOT) implies immunosuppression and frequent health care contact. Our aim was to compare the characteristics of patients with infective endocarditis (IE) and SOT against ...those without SOT.
We used data from the Spanish Collaboration on Endocarditis during the period 2008-2018.
We identified 4794 cases of IE, 85 (1.8%) in SOT (56 kidney, 18 liver, 8 heart, 3 lung). Thirteen patients with other transplantation types (bone marrow, hematopoietic precursors, and cornea) were excluded from the analysis. Compared with patients without SOT, patients with SOT had lower median age (61 vs. 69 years, p<0.001), more comorbidities (mean age-adjusted Charlson index 5.7±2.9 vs. 4.9±2.9, p=0.004), a lower prevalence of native valvular heart disease (29.4 vs. 45.4%, p=0.003), more in-hospital and healthcare-related IE (70.5% vs. 36.3%, p<0.001) and staphylococcal etiology (57.7% vs. 39.7%, p=0.001). Patients with SOT had more frequent kidney function worsening (47.1% vs. 34.6%, p=0.02), septic shock (25.9% vs. 12.1 %, p<0.001), sepsis (27.1% vs. 17.2%, p=0.02), and less surgery indication (54.1% vs 66.3%, p=0.02) and surgery (32.9% vs. 46.3%, p=0.01) than patients without SOT. There were no significant differences in mortality: inhospital (30.6% SOT vs. 25.6% without SOT, p=0.31), 1-year (38.8% SOT vs. 31.9% without SOT, p=0.18).
Most IE in SOT recipients are nosocomial and over 70% are health care-related. Half have previously normal heart valves and almost 60% are due to Staphylococcus spp. infections. Mortality seems to be similar to non-SOT counterparts.
In scenarios where the use of a Computed Tomography (CT) is difficult, such as during surgery or in the ICU, the use of a C-arm system to generate tomographic information could contribute with ...interesting additional clinical information. Recent days are seeing the development of the so-called cone-beam CT (CBCT) based on advanced motorized isocentric C-arm systems. To be able to make use of more basic C-arm systems, apart from the geometric non-idealities common to any CBCT, we need to address other difficulties. First, the trajectory of the source-detector pair may differ from a circular path and the system may suffer mechanical strains that modify the relative positions of the source and detector for different projection angles. Second, and more importantly, the exact position of the source and detector elements may not be repeatable for consecutive rotations due to low mechanical precision, thus preventing an accurate geometrical calibration of the system. Finally, the limitation of the angular span and the difficulty of obtaining a high number of projections pose a great challenge to the image reconstruction. In this work, we present a novel method to adapt a standard C-arm, originally designed for planar imaging, to be used as a tomograph. The key parts of the new acquisition protocol are (1) a geometrical calibration method to compensate mechanical inaccuracies that prevent an accurate repetition of source-detector position between acquisitions, and (2) an advanced image reconstruction method able to deal with limited angle data, sparse projections and non-circular trajectories. Both methods exploit surface information from the patient, which can be obtained using a 3D surface scanner. The proposed method was evaluated with two real C-arm systems, based on an image intensifier and a flat panel detector respectively, showing the feasibility of the proposal.
Analysis of the T cell receptor (TR) repertoire of chronic lymphocytic leukemia-like monoclonal B cell lymphocytosis (CLL-like MBL) and early stage CLL is relevant for understanding the dynamic ...interaction of expanded B cell clones with bystander T cells. Here we profiled the T cell receptor β chain (TRB) repertoire of the CD4
+
and CD8
+
T cell fractions from 16 CLL-like MBL and 13 untreated, Binet stage A/Rai stage 0 CLL patients using subcloning analysis followed by Sanger sequencing. The T cell subpopulations of both MBL and early stage CLL harbored restricted TRB gene repertoire, with CD4
+
T cell clonal expansions whose frequency followed the numerical increase of clonal B cells. Longitudinal analysis in MBL cases revealed clonal persistence, alluding to persistent antigen stimulation. In addition, the identification of shared clonotypes among different MBL/early stage CLL cases pointed towards selection of the T cell clones by common antigenic elements. T cell clonotypes previously described in viral infections and immune disorders were also detected. Altogether, our findings evidence that antigen-mediated TR restriction occurs early in clonal evolution leading to CLL and may further increase together with B cell clonal expansion, possibly suggesting that the T cell selecting antigens are tumor-related.
► Behaviour with 100% recycled coarse aggregate under sustained loading was studied. ► To do it tests under low loading rates in compression and tension were developed. ► Strength decreases were ...similar to those with conventional concrete. ► Other analysis (longitudinal strain, volumetric strain and damage) indicated the same result. ► So, recycled concretes show no special differences with conventional concretes.
In this work the influence of the substitution of 100% of natural coarse aggregate with recycled coarse aggregate has been analysed in order to know the behaviour of the structural concrete in one particular aspect: that is, the behaviour of the recycled concretes under sustained load.
To know the behaviour under sustained load, tests under very low loading rate were carried out, using concretes with 100% of recycled coarse aggregate. The results indicated that the ratio of strength under very low loading rate over strength under standard loading rate in compression and in tension is very similar in conventional and recycled concretes.
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