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4D Flow MRI is a quantitative imaging technique to evaluate blood flow patterns; however, it is unclear how compressed sensing (CS) acceleration would impact aortic hemodynamic quantification in type B aortic dissection (TBAD).To investigate CS-accelerated 4D Flow MRI performance compared to GRAPP-accelerated 4D Flow MRI (GRAPPA) to evaluate aortic hemodynamics in TBAD.Prospective.Twelve TBAD patients, two volunteers.1.5T, 3D time-resolved cine phase-contrast gradient echo sequence.GRAPPA (acceleration factor [R] = 2) and two CS-accelerated (R = 7.7 [CS7.7] and 10.2 [CS10.2]) 4D Flow MRI scans were acquired twice for interscan reproducibility assessment. Voxelwise kinetic energy (KE), peak velocity (PV), forward flow (FF), reverse flow (RF), and stasis were calculated. Plane-based mid-lumen flows were quantified. Imaging times were recorded.Repeated measures analysis of variance, Pearson correlation coefficients (r), intraclass correlation coefficients (ICC). P 0.05 indicated statistical significance.The KE and FF in true lumen (TL) and PV in false lumen (FL) did not show difference among three acquisition types (P = 0.818, 0.065, 0.284 respectively). The PV and stasis in TL were higher, KE, FF, and RF in FL were lower, and stasis was higher in GRAPPA compared to CS7.7 and CS10.2. The RF was lower in GRAPPA compared to CS10.2. The correlation coefficients were strong in TL (r = [0.781-0.986]), and low to strong in FL (r = [0.347-0.948]). The ICC levels demonstrated moderate to excellent interscan reproducibility (0.732-0.989). The FF and net flow in mid-descending aorta TL were significantly different between CS7.7 and CS10.2.CS-accelerated 4D Flow MRI has potential for clinical utilization with shorter scan times in TBAD. Our results suggest similar hemodynamic trends between acceleration types, but CS-acceleration impacts KE, FF, RF, and stasis more in FL.1 Technical Efficacy: Stage 2.

To evaluate hemodynamic markers obtained by accelerated GRAPPA (R = 2, 3, 4) and compressed sensing (R = 7.6) 4D flow MRI sequences under complex flow conditions.The accelerated 4D flow MRI scans were performed on a pulsatile flow phantom, along with a nonaccelerated fully sampled k-space acquisition. Computational fluid dynamics simulations based on the experimentally measured flow fields were conducted for additional comparison. Voxel-wise comparisons (Bland-Altman analysis,mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"mml:semanticsmml:mrowmml:msubmml:miL/mml:mimml:mn2/mml:mn/mml:msub/mml:mrowmml:annotation$$ {L}_2 $$/mml:annotation/mml:semantics/mml:math-norm metric), as well as nonderived quantities (velocity profiles, flow rates, and peak velocities), were used to compare the velocity fields obtained from the different modalities.4D flow acquisitions and computational fluid dynamics depicted similar hemodynamic patterns. Voxel-wise comparisons between the MRI scans highlighted larger discrepancies at the voxels located near the phantom's boundary walls. A trend for all MR scans to overestimate velocity profiles and peak velocities as compared to computational fluid dynamics was noticed in regions associated with high velocity or acceleration. However, good agreement for the flow rates was observed, and eddy-current correction appeared essential for consistency of the flow rates measurements with respect to the principle of mass conservation.GRAPPA (R = 2, 3) and highly accelerated compressed sensing showed good agreement with the fully sampled acquisition. Yet, all 4D flow MRI scans were hampered by artifacts inherent to the phase-contrast acquisition procedure. Computational fluid dynamics simulations are an interesting tool to assess these differences but are sensitive to modeling parameters.

Purpose Flow quantification by phase‐contrast MRI is hampered by spatially varying background phase offsets. Correction performance by polynomial regression on stationary tissue may be affected by outliers such as wrap‐around or constant flow. Therefore, we propose an alternative, M‐estimate SAmple Consensus (MSAC) to reject outliers, and improve and fully automate background phase correction. Methods The MSAC technique fits polynomials to randomly drawn small samples from the image. Over several trials, it aims to find the best consensus set of valid pixels by rejecting outliers to the fit and minimizing the residuals of the remaining pixels. The robustness of MSAC to its few parameters was investigated and verified using third‐order polynomial correction fits on a total of 118 2D flow (97 with wrap‐around) and 18 4D flow data sets (14 with wrap‐around), acquired at 1.5 T and 3 T. Background phase was compared with standard stationary correction and phantom correction. Pulmonary/systemic flow ratios in 2D flow were derived, and exemplary 4D flow analysis was performed. Results The MSAC technique is robust over a range of parameter choices, and a unique set of parameters is suitable for both 2D and 4D flow. In 2D flow, phase errors were significantly reduced by MSAC compared with stationary correction (p = 0.005), and stationary correction shows larger errors in pulmonary/systemic flow ratios compared with MSAC. In 4D flow, MSAC shows similar performance as stationary correction. Conclusions The MSAC method provides fully automated background phase correction to 2D and 4D flow data and shows improved robustness over stationary correction, especially with outliers present.

In NMR spectroscopy, residual dipolar couplings (RDCs) have emerged as one of the most exquisite probes of biological structure and dynamics. The measurement of RDCs relies on the partial alignment of the molecule of interest, for example by using a liquid crystal as a solvent. Here, we establish bacterial type 1 pili as an alternative liquid-crystalline alignment medium for the measurement of RDCs. To achieve alignment at pilus concentrations that allow for efficient NMR sample preparation, we elongated wild-type pili by recombinant overproduction of the main structural pilus subunit. Building on the extraordinary stability of type 1 pili against spontaneous dissociation and unfolding, we show that the medium is compatible with challenging experimental conditions such as high temperature, the presence of detergents, organic solvents or very acidic pH, setting it apart from most established alignment media. Using human ubiquitin, HIV-1 TAR RNA and camphor as spectroscopic probes, we demonstrate the applicability of the medium for the determination of RDCs of proteins, nucleic acids and small molecules. Our results show that type 1 pili represent a very useful alternative to existing alignment media and may readily assist the characterization of molecular structure and dynamics by NMR., Angewandte Chemie. International Edition, ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833

BACKGROUND: In the absence of lung biopsy there are various algorithms for the diagnosis of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients that rely on clinical signs, underlying conditions, radiological features, and mycology. The aim of the present study was to compare four diagnostic algorithms in their ability to differentiate between probable IPA (i.e. requiring treatment) and colonization in critically ill patients. In addition, we determined their diagnostic accuracy to detect proven IPA.METHODS: For this diagnostic accuracy study, we included a mixed ICU population with a positive Aspergillus culture from respiratory secretions that were treated in a German quarternary care hospital between 2005 and 2020. Four different diagnostic algorithms were applied to all patients. We compared agreement among the four algorithms to discriminate probable IPA from colonization. In a subgroup of patients with lung tissue histopathology available we determined the sensitivity and specificity of the single algorithms to detect proven IPA. RESULTS: A total number of 684 critically ill patients were included. The mean age of the study population was 63 years (IQR 52-73). Sixty-nine percent (n=472) were medical and 31% (n=212) were surgical ICU patients. Overall, 79% (n=543) of patients fulfilled the criteria for probable IPA according to at least one diagnostic algorithm. Only 4% of patients (n=29) fulfilled the criteria for probable IPA according to all four algorithms. Agreement among the four diagnostic criteria was low (Cohen’s kappa 0.07-0.29). From 85 patients with histopathological examination of lung tissue 40% (n=34) had confirmed IPA. The new EORTC/MSGERC ICU working group criteria had high specificity (0.59 [0.41-0.75]) and sensitivity (0.73 [0.59-0.85]).CONCLUSIONS:In a cohort of mixed ICU patients, the agreement among four algorithms for the diagnosis of IPA was low. The 2021 EORTC/MSGERC ICU working group criteria achieved the highest specificity and sensitivity to detect proven IPA. Although improved by the latest diagnostic criteria, the discrimination of invasive fungal infection from Aspergillus colonization in critically ill patients remains challenging and may require further optimization.

Vascular tumors and malformations present a diagnostic and therapeutic challenge to many physicians. Because these lesions are rare, few surgeons have enough experience with them other than those practicing in tertiary vascular anomaly treatment centers. Some patients may have been misdiagnosed or mistreated during childhood and present in adult age with either recurrence or with an untreated lesion. Ideally, a multidisciplinary treatment team should be involved to discuss management with the patient including specialists in surgery, interventional radiology, pathology, hematology, genetics, and dermatology. As our understanding of the pathogenesis of these lesions grows, novel therapies are being employed which may decrease the need for surgery. Nevertheless, some lesions need definitive treatment with surgery. Improving understanding of the surgical management of vascular anomalies will improve cosmetic and functional outcomes for patients.

Paw pads are specializations of the integument and important shock absorbers of the locomotor system, as well as pressure, pain, temperature, storage and excretion sensors. Aiming to describe the paw pad morphology of the main arboreal xenarthras species in the Amazon, 16 animals were studied, Bradypus variegatus (6), Choloepus didactylus (5), Tamandua tetradactyla (3) and Cyclopes didactylus (2) that after death were donated to the Animal Morphological Research Laboratory (LaPMA / Ufra). The corpses were thawed and fixed with 10% aqueous formalin solution. The paw pads were measured, photographed and removed by skin incision dorsally to them. Fragments were used for routine histological processing, using two staining techniques: Hematoxylin-Eosin (HE) and Gomori's Trichrome, in sections of 6 to 8 µm. Choloepus didactylus, Tamandua tetradactyla and Cyclopes didactylus have digital paw pads, one in each digit, and one palm, as well as a plantar, whose shapes and colours are distinct from each other. Bradypus variegatus, however, has only one palmar and one plantar pad. Histologically, they have keratinized stratified squamous epithelium, supported by a large amount of collagen fibres and fibroblast cords in the dermis and hypodermis. Groups of eccrine sweat glands were observed in the reticular dermis of C. didactylus, B. variegatus, T. tetradactyla and only in the hypodermis of Cyclopes didactylus.

The Insect Allies program of the Defense Advanced Research Projects Agency has already sparked scientific debate concerning technology assessment-related issues, among which the most prevalent is that of dual use. Apart from the issues concerning peaceful applications, the technology also provides the blueprint for a potential bioweapon. However, the combination of a virus-induced genetic modification of crop plants in the field using genetically modified insect vectors poses a greater risk than the hitherto existing use of genetically modified organisms. The technology's great depth of intervention allows a number of sources for hazard and a tendency towards high exposure, but it is also encumbered with notable deficits in knowledge. These issues call for a thorough technology assessment. This article aims to provide an initial characterization from a technology assessment perspective, focusing on potential sources of risk for this novel invasive environmental biotechnology at an early stage of research and development. Integr Environ Assess Manag 2022;18:1488-1499. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental ToxicologyChemistry (SETAC).