Multicenter evaluation of left ventricular assist device implantation with or without ECMO bridge in cardiogenic shock.

BACKGROUND: The efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to left ventricular assist device (LVAD) remains unclear, and recipients of the more contemporary HeartMate 3 (HM3) LVAD are not well represented in previous studies. We therefore undertook a multicenter, retrospective study of this population. METHODS AND RESULTS: INTERMACS 1 LVAD recipients from five U.S. centers were included. In-hospital and one-year outcomes were recorded. The primary outcome was the overall mortality hazard comparing ECMO versus non-ECMO patients by propensity-weighted survival analysis. Secondary outcomes included survival by LVAD type, as well as postoperative and one-year outcomes. One hundred and twenty-seven patients were included; 24 received ECMO as a bridge to LVAD. Mortality was higher in patients bridged with ECMO in the primary analysis (HR 3.22 [95%CI 1.06-9.77], p = 0.039). Right ventricular assist device was more common in the ECMO group (ECMO: 54.2% vs non-ECMO: 11.7%, p < 0.001). Ischemic stroke was higher at one year in the ECMO group (ECMO: 25.0% vs non-ECMO: 4.9%, p = 0.006). Among the study cohort, one-year mortality was lower in HM3 than in HeartMate II (HMII) or HeartWare HVAD (10.5% vs 46.9% vs 31.6%, respectively; p < 0.001) recipients. Pump thrombosis at one year was lower in HM3 than in HMII or HVAD (1.8% vs 16.1% vs 16.2%, respectively; p = 0.026) recipients. CONCLUSIONS: Higher mortality was observed with ECMO as a bridge to LVAD, likely due to higher acuity illness, yet acceptable one-year survival was seen compared with historical rates. The receipt of the HM3 was associated with improved survival compared with older generation devices.

Investigation of alternative RF power limit control methods for 0.5T, 1.5T, and 3T parallel transmission cardiac imaging: A simulation study.

PURPOSE: To investigate safety and performance aspects of parallel-transmit (pTx) RF control-modes for a body coil at B 0 ≤ 3 T $$ {B}_0\le 3\mathrm{T} $$ . METHODS: Electromagnetic simulations of 11 human voxel models in cardiac imaging position were conducted for B 0 = 0.5 T $$ {B}_0=0.5\mathrm{T} $$ , 1.5 T $$ 1.5\mathrm{T} $$ and 3 T $$ 3\mathrm{T} $$ and a body coil with a configurable number of transmit channels (1, 2, 4, 8, 16). Three safety modes were considered: the 'SAR-controlled mode' (SCM), where specific absorption rate (SAR) is limited directly, a 'phase agnostic SAR-controlled mode' (PASCM), where phase information is neglected, and a 'power-controlled mode' (PCM), where the voltage amplitude for each channel is limited. For either mode, safety limits were established based on a set of 'anchor' simulations and then evaluated in 'target' simulations on previously unseen models. The comparison allowed to derive safety factors accounting for varying patient anatomies. All control modes were compared in terms of the B 1 + $$ {B}_1^{+} $$ amplitude and homogeneity they permit under their respective safety requirements. RESULTS: Large safety factors (approximately five) are needed if only one or two anchor models are investigated but they shrink with increasing number of anchors. The achievable B 1 + $$ {B}_1^{+} $$ is highest for SCM but this advantage is reduced when the safety factor is included. PCM appears to be more robust against variations of subjects. PASCM performance is mostly in between SCM and PCM. Compared to standard circularly polarized (CP) excitation, pTx offers minor B 1 + $$ {B}_1^{+} $$ improvements if local SAR limits are always enforced. CONCLUSION: PTx body coils can safely be used at B 0 ≤ 3 T $$ {B}_0\le 3\mathrm{T} $$ . Uncertainties in patient anatomy must be accounted for, however, by simulating many models.

Age of epilepsy onset as modulating factor for naming deficit after epilepsy surgery: a voxel-based lesion-symptom mapping study.

Age at onset of epilepsy is an important predictor of deterioration in naming ability following epilepsy surgery. In 141 patients with left hemispheric epilepsy and language dominance who received epilepsy surgery at the Epilepsy Centre Erlangen, naming of objects (Boston naming test, BNT) was assessed preoperatively and 6 months postoperatively. Surgical lesions were plotted on postoperative MRI and normalized for statistical analysis using voxel-based lesion-symptom mapping (VBLSM). The correlation between lesion and presence of postoperative naming deterioration was examined varying the considered age range of epilepsy onsets. The VBLSM analysis showed that volumes of cortex areas in the left temporal lobe, which were associated with postoperative decline of naming, increased with each year of later epilepsy onset. In patients with later onset, an increasing left posterior temporobasal area was significantly associated with a postoperative deficit when included in the resection. For late epilepsy onset, the temporomesial expansion also included the left hippocampus. The results underline that early onset of epilepsy is a good prognostic factor for unchanged postoperative naming ability following epilepsy surgery. For later age of epilepsy onset, the extent of the area at risk of postoperative naming deficit at 6 months after surgery included an increasing left temporobasal area which finally also comprised the hippocampus.

Wirelessly interfacing sensor-equipped implants and MR scanners for improved safety and imaging.

PURPOSE: To investigate a novel reduced RF heating method for imaging in the presence of active implanted medical devices (AIMDs) which employs a sensor-equipped implant that provides wireless feedback. METHODS: The implant, consisting of a generator case and a lead, measures RF-induced E $$ E $$ -fields at the implant tip using a simple sensor in the generator case and transmits these values wirelessly to the MR scanner. Based on the sensor signal alone, parallel transmission (pTx) excitation vectors were calculated to suppress tip heating and maintain image quality. A sensor-based imaging metric was introduced to assess the image quality. The methodology was studied at 7T in testbed experiments, and at a 3T scanner in an ASTM phantom containing AIMDs instrumented with six realistic deep brain stimulation (DBS) lead configurations adapted from patients. RESULTS: The implant successfully measured RF-induced E $$ E $$ -fields (Pearson correlation coefficient squared [R2 ] = 0.93) and temperature rises (R2 = 0.95) at the implant tip. The implant acquired the relevant data needed to calculate the pTx excitation vectors and transmitted them wirelessly to the MR scanner within a single shot RF sequence (<60 ms). Temperature rises for six realistic DBS lead configurations were reduced to 0.03-0.14 K for heating suppression modes compared to 0.52-3.33 K for the worst-case heating, while imaging quality remained comparable (five of six lead imaging scores were ≥0.80/1.00) to conventional circular polarization (CP) images. CONCLUSION: Implants with sensors that can communicate with an MR scanner can substantially improve safety for patients in a fast and automated manner, easing the current burden for MR personnel.

Incidence, temporal profile and neuroanatomic correlates of poststroke epilepsy.

BACKGROUND AND PURPOSE: The relationship between ischemic stroke site and occurrence of poststroke epilepsy (PSE) is incompletely understood. This study intended to evaluate incidence and temporal profiles of seizures and to correlate ischemic lesion sites with PSE using voxel-based lesion symptom mapping (VLSM). METHODS: Patients with imaging-confirmed first-ever ischemic stroke without prior history of epilepsy were prospectively included. Demographic data, cardiovascular risk factors, and National Institute of Health Stroke Scale (NIHSS) scores were assessed. Data on seizures and modified Rankin scale scores were determined within a 90-day period after stroke onset. Ischemic lesion sites were correlated voxel wise with occurrence of PSE using nonparametric permutation test. Age- and sex-matched patients with first-ever ischemic strokes without PSE after 90 days served as controls for the VLSM analysis. RESULTS: The stroke database contained 809 patients (mean age: 68.4 ± 14.2 years) with first-ever imaging-confirmed ischemic strokes without history of epilep. Incidence of PSE after 90-day follow-up was 2.8%. Five additional patients were admitted to the emergency department with a seizure after 90-day follow-up. Fifty percent of the seizures occurred in the acute phase after stroke. PSE patients had higher NIHSS scores and infarct volumes compared to controls without PSE (p < .05). PSE patients had infarcts predominantly involving the cerebral cortex. The hemisphere-specific VLSM analysis shows associations between PSE and damaged voxels in the left-hemispheric temporo-occipital transition zone. CONCLUSIONS: The data indicate that PSE occurs in a small proportion of patients with rather large ischemic strokes predominantly involving the cerebral cortex. Especially patients with ischemic lesions in the temporo-occipital cortex are vulnerable to develop PSE.

Toward a roadmap for space-based observations of the land sector for the UNFCCC global stocktake.

Space-based remote sensing can make an important contribution toward monitoring greenhouse gas emissions and removals from the agriculture, forestry, and other land use (AFOLU) sector, and to understanding and addressing human-caused climate change through the UNFCCC Paris Agreement. Space agencies have begun to coordinate their efforts to identify needs, collect and harmonize available data and efforts, and plan and maintain a long-term roadmap for observations. International cooperation is crucial in developing and realizing the roadmap, and the Committee on Earth Observation Satellites (CEOS) is a key coordinating driver of this effort. Here, we first identify the data and information that will be useful to support the global stocktake (GST) of the Paris Agreement. Then, the paper explains how existing and planned space-based capabilities and products can be used and combined, particularly in the land use sector, and provides a workflow for their harmonization and contribution to greenhouse gas inventories and assessments at the national and global level.

Physical behavior of PEDOT polymer electrode during magnetic resonance imaging and long-term test in the climate chamber.

The PEDOT polymer electrode is a metal-free electrode, consisting of an acrylate (dental composite) and the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The electrode is applied as gel onto the skin and cured with blue light for 10-20 s in order to achieve a conductive bond to the skin. The electrodes are used in combination with polymer cables consisting of a textile backbone and PEDOT:PSS. To test this new electrode and cable type under different conditions we designed two stress-tests: highly sensitive temperature recordings within a head phantom during Magnetic Resonance Imaging (MRI) and long-term stability inside a climate chamber with high humidity. To study the physical behavior inside the strong magnetic field (3 Tesla), the PEDOT polymer electrode was attached to an agarose head-phantom inside a magnetic resonance tomograph during an image sequence. MRI-safe temperature sensors were placed nearby in order to measure possible heating effects. In comparison to a metal cable, nearly no rise in temperature could be observed if the electrode was used in combination with a conductive textile cable. Furthermore, the electrode showed stable impedance values inside a climate chamber for 4 consecutive days. These results pave the way for testing the PEDOT polymer electrode as biosignal recording electrode during MRI, especially for cardio MRI and Electroencephalography in combination with functional MRI (EEG-fMRI).

Ultra-wide band radar for prospective respiratory motion correction in the liver.

Objective.T1 mapping of the liver is time consuming and can be challenging due to respiratory motion. Here we present a prospective slice tracking approach, which utilizes an external ultra-wide band radar signal and allows for efficient T1 mapping during free-breathing.Approach.The fast radar signal is calibrated to an MR-based motion signal to create a motion model. This motion model provides motion estimates, which are used to carry out slice tracking for any subsequent clinical scan. This approach was evaluated in simulations, phantom experiments andin vivoscans.Main results.Radar-based slice tracking was implemented on an MR system with a total latency of 77 ms. Moving phantom experiments showed accurate motion prediction with an error of 0.12 mm in anterior-posterior and 0.81 mm in head-feet direction. The model error remained stable for up to two hours.In vivoexperiments showed visible image improvement with a motion model error three times smaller than with a respiratory bellow. For T1 mapping during free-breathing the proposed approach provided similar results compared to reference T1 mapping during a breathhold.Significance.The proposed radar-based approach achieves accurate slice tracking and enables efficient T1 mapping of the liver during free-breathing. This motion correction approach is independent from scanning parameters and could also be used for applications like MR guided radiotherapy or MR Elastography.

Acute right insular ischaemic lesions and poststroke left ventricular dysfunction.

INTRODUCTION: Myocardial injury related to acute ischaemic stroke is common even without primary cardiac disease. We intended to determine associations between values of left ventricular ejection fraction (LVEF) and ischaemic stroke lesion sites. METHODS: Of a local database, patients with acute first-ever ischaemic stroke confirmed by brain imaging but without pre-existing heart disease were included. The cardiac morphology and LVEF were obtained from transthoracic or transesophageal echocardiography, and impaired LVEF was categorised as mild (35%-50%), moderate (34%-25%) and severe (<25%). Patient age, stroke severity, ischaemic lesion volume, prevalence of troponin I increase (>0.1 ng/mL), atrial fibrillation and cardiac wall motion abnormalities were assessed and compared between patients with and without impaired LVEF after stroke (significance: p<0.05). A multivariate voxelwise lesion analysis correlated LVEF after stroke with sites of ischaemic lesions. RESULTS: Of 1209 patients who had a stroke, 231 (mean age 66.3±14.0 years) met the inclusion criteria; 40 patients (17.3%) had an impaired LVEF after stroke. Patients with impaired LVEF had higher infarct volumes (53.8 mL vs 30.0 mL, p=0.042), a higher prevalence of troponin increase (17.5% vs 4.2%, p=0.006), cardiac wall motion abnormalities (42.5% vs 5.2%, p<0.001) and atrial fibrillation (60.0% vs 26.2%, p<0.001) than patients with LVEF of >50%. The multivariate voxelwise lesion analysis yielded associations between decreased LVEF and damaged voxels in the insula, amygdala and operculum of the right hemisphere. CONCLUSION: Our imaging analysis unveils a prominent role of the right hemispheric central autonomic network, especially of the insular cortex, in the brain-heart axis. Our results support preliminary evidence that acute ischaemic stroke in distinct brain regions of the central autonomic network may directly impair cardiac function and thus further supports the concept of a distinct stroke-heart syndrome.

Towards an integrated radiofrequency safety concept for implant carriers in MRI based on sensor-equipped implants and parallel transmission.

To protect implant carriers in MRI from excessive radiofrequency (RF) heating it has previously been suggested to assess that hazard via sensors on the implant. Other work recommended parallel transmission (pTx) to actively mitigate implant-related heating. Here, both ideas are integrated into one comprehensive safety concept where native pTx safety (without implant) is ensured by state-of-the-art field simulations and the implant-specific hazard is quantified in situ using physical sensors. The concept is demonstrated by electromagnetic simulations performed on a human voxel model with a simplified spinal-cord implant in an eight-channel pTx body coil at 3 T . To integrate implant and native safety, the sensor signal must be calibrated in terms of an established safety metric (e.g., specific absorption rate [SAR]). Virtual experiments show that E -field and implant-current sensors are well suited for this purpose, while temperature sensors require some caution, and B 1 probes are inadequate. Based on an implant sensor matrix Q s , constructed in situ from sensor readings, and precomputed native SAR limits, a vector space of safe RF excitations is determined where both global (native) and local (implant-related) safety requirements are satisfied. Within this safe-excitation subspace, the solution with the best image quality in terms of B 1 + magnitude and homogeneity is then found by a straightforward optimization algorithm. In the investigated example, the optimized pTx shim provides a 3-fold higher mean B 1 + magnitude compared with circularly polarized excitation for a maximum implant-related temperature increase ∆ T imp ≤ 1 K . To date, sensor-equipped implants interfaced to a pTx scanner exist as demonstrator items in research labs, but commercial devices are not yet within sight. This paper aims to demonstrate the significant benefits of such an approach and how this could impact implant-related RF safety in MRI. Today, the responsibility for safe implant scanning lies with the implant manufacturer and the MRI operator; within the sensor concept, the MRI manufacturer would assume much of the operator's current responsibility.

Clinical, serological and genetic predictors of response to immunotherapy in anti-IgLON5 disease.

Anti-IgLON5 disease is a newly defined clinical entity characterized by a progressive course with high disability and mortality rate. While precise pathogenetic mechanisms remain unclear, features characteristic of both autoimmune and neurodegenerative diseases were reported. Data on immunotherapy are limited, and its efficacy remains controversial. In this study, we retrospectively investigated an anti-IgLON5 disease cohort with special focus on clinical, serological and genetic predictors of the immunotherapy response and long-term outcome. Patients were recruited from the GENERATE (German Network for Research on Autoimmune Encephalitis) registry. Along with clinical parameters, anti-IgLON5 immunoglobulin (Ig)G in serum and CSF, anti-IgLON5 IgG1-4, IgA and IgM in serum, neurofilament light chain and glial fibrillary acidic protein in serum as well as human leukocyte antigen-genotypes were determined. We identified 53 patients (symptom onset 63.8 ± 10.3 years, female:male 1:1.5). The most frequent initial clinical presentations were bulbar syndrome, hyperkinetic syndrome or isolated sleep disorder [at least one symptom present in 38% (20/53)]. At the time of diagnosis, the majority of patients had a generalized multi-systemic phenotype; nevertheless, 21% (11/53) still had an isolated brainstem syndrome and/or a characteristic sleep disorder only. About one third of patients [28% (15/53)] reported subacute disease onset and 51% (27/53) relapse-like exacerbations during the disease course. Inflammatory CSF changes were evident in 37% (19/51) and increased blood-CSF-barrier permeability in 46% (21/46). CSF cell count significantly decreased, while serum anti-IgLON5 IgG titre increased with disease duration. The presence of human leukocyte antigen-DRB1*10:01 [55% (24/44)] was associated with higher serum anti-IgLON5 IgG titres. Neurofilament light chain and glial fibrillary acidic protein in serum were substantially increased (71.1 ± 103.9 pg/ml and 126.7 ± 73.3 pg/ml, respectively). First-line immunotherapy of relapse-like acute-to-subacute exacerbation episodes resulted in improvement in 41% (11/27) of patients and early initiation within the first 6 weeks was a predictor for therapy response. Sixty-eight per cent (36/53) of patients were treated with long-term immunotherapy and 75% (27/36) of these experienced no further disease progression (observation period of 20.2 ± 15.4 months). Long-term immunotherapy initiation during the first year after onset and low pre-treatment neurofilament light chain were significant predictors for a better outcome. In conclusion, subacute disease onset and early inflammatory CSF changes support the primary role of autoimmune mechanisms at least at initial stages of anti-IgLON5 disease. Early immunotherapy, prior to advanced neurodegeneration, is associated with a better long-term clinical outcome. Low serum neurofilament light chain at treatment initiation may serve as a potential biomarker of the immunotherapy response.

Resection of dominant fusiform gyrus is associated with decline of naming function when temporal lobe epilepsy manifests after the age of five: A voxel-based lesion-symptom mapping study.

OBJECTIVE: To determine patients' characteristics and regions in the temporal lobe where resections lead to a decline in picture naming. METHODS: 311 patients with left hemispheric dominance for language were included who underwent epilepsy surgery at the Epilepsy Center of Erlangen and whose picture naming scores (Boston Naming Test, BNT) were available preoperatively and 6-months postoperatively. Surgical lesions were mapped to an averaged template based on preoperative and postoperative MRI using voxel-based lesion-symptom mapping (VBLSM). Postoperative brain shifts were corrected. The relationship between lesioned brain areas and the presence of a postoperative naming decline was examined voxel-wise while controlling for effects of overall lesion size at first in the total cohort and then restricted to temporal lobe resections. RESULTS: In VBLSM in the total sample, a decline in BNT score was significantly related to left temporal surgery. When only considering patients with left temporal lobe resections (n = 121), 40 (33.1%) significantly worsened in BNT postoperatively. VBLSM including all patients with left temporal resections generated no significant results within the temporal lobe. However, naming decline of patients with epilepsy onset after 5 years of age was significantly associated with resections in the left inferior temporal (extent of BNT decline range: 10.8- 14.4%) and fusiform gyrus (decline range: 12.1-18.4%). SIGNIFICANCE: Resections in the posterior part of the dominant fusiform and inferior temporal gyrus was associated with a risk of deterioration in naming performance at six months after surgery in patients with epilepsy onset after 5 years of age but not with earlier epilepsy onset.

The impact of respiratory motion on electromagnetic fields and specific absorption rate in cardiac imaging at 7T.

PURPOSE: To present electromagnetic simulation setups for detailed analyses of respiration's impact on B 1 + $$ {B}_1^{+} $$ and E-fields, local specific absorption rate (SAR) and associated safety-limits for 7T cardiac imaging. METHODS: Finite-difference time-domain electromagnetic field simulations were performed at five respiratory states using a breathing body model and a 16-element 7T body transceiver RF-coil array. B 1 + $$ {B}_1^{+} $$ and SAR are analyzed for fixed and moving coil configurations. SAR variations are investigated using phase/amplitude shimming considering (i) a local SAR-controlled mode (here SAR calculations consider RF amplitudes and phases) and (ii) a channel-wise power-controlled mode (SAR boundary calculation is independent of the channels' phases, only dependent on the channels' maximum amplitude). RESULTS: Respiration-induced variations of both B 1 + $$ {B}_1^{+} $$ amplitude and phase are observed. The flip angle homogeneity depends on the respiratory state used for B 1 + $$ {B}_1^{+} $$ shimming; best results were achieved for shimming on inhale and exhale simultaneously ( | Δ C V | < 35 % $$ \mid \Delta CV\mid <35\% $$ ). The results reflect that respiration impacts position and amplitude of the local SAR maximum. With the local-SAR-control mode, a safety factor of up to 1.4 is needed to accommodate for respiratory variations while the power control mode appears respiration-robust when the coil moves with respiration (SAR peak decrease: 9% exhale→inhale). Instead, a spatially fixed coil setup yields higher SAR variations with respiration. CONCLUSION: Respiratory motion does not only affect the B 1 + $$ {B}_1^{+} $$ distribution and hence the image contrast, but also location and magnitude of the peak spatial SAR. Therefore, respiration effects may need to be included in safety analyses of RF coils applied to the human thorax.

Voxel-wise lesion mapping of restless legs syndrome in multiple sclerosis.

OBJECTIVE: Restless legs syndrome (RLS) is known to be associated with multiple sclerosis (MS) and may be caused by MS lesions in specific cerebral brain regions. Applying a voxel-wise lesion analysis, we tried to identify the contribution of cerebral MS lesions to RLS. METHODS: In this retrospective study, we established a cohort of people with MS with documented RLS and controls of people with MS without RLS matched disease severity. Diagnosis of MS and RLS was based on the current guidelines. The MS lesions were analyzed on T2-weighted magnetic resonance imaging scans (1.5 or 3 T). After manual delineation, lesion maps were converted into stereotaxic space. We generated a lesion overlap and performed a Liebermeister test with 4000 permutations to compare the absence or presence of RLS voxel-wise between patients with and without lesions in a given voxel. RESULTS: Forty of the patients with RLS and MS fulfilled the inclusion criteria. The voxel-wise analysis yielded associations between RLS and MS in the subcortex of the left gyrus precentralis. CONCLUSION: Our voxel-wise analysis shows associations in the subcortex of the left gyrus precentralis. Thus, our data suggests that a dysfunction of the efferent motor system due to cerebral lesions may contribute to the pathophysiology of RLS in MS.

CoSimPy: An open-source python library for MRI radiofrequency Coil EM/Circuit Cosimulation.

BACKGROUND AND OBJECTIVES: The Electromagnetic/Circuit cosimulation method represents a valuable and effective strategy to address those problems where a radiative structure has to interact with external supporting circuitries. This is of particular concern for Magnetic Resonance Imaging (MRI), radiofrequency (RF) coils design, where the supporting circuitry optimisation represents, generally, a crucial aspect. This article presents CoSimPy, an open-source Python circuit simulation library for Electromagnetic/Circuit cosimulations and specifically optimised for MRI, RF coils design. METHODS: CoSimPy is designed following an Object-orientated programming. In addition to the essential methods aimed to performed the Electromagnetic/Circuit cosimulations, many others are implemented both to simplify the standard workflow and to evaluate the RF coils performance. In this article, the theory which underlies the fundamental methods of CoSimPy is shown together with the basic framework of the library. RESULTS: In the paper, the reliability of CoSimPy is successfully tested against a full-wave electromagnetic simulations involving a reference setup. The library is made available under https://github.com/umbertozanovello/CoSimPy together with a detailed documentation providing guidelines and examples. CoSimPy is distributed under the Massachusetts Institute of Technology (MIT) license. CONCLUSIONS: CoSimPy demonstrated to be an agile tool employable for Electromagnetic/Circuit cosimulations. Its distribution is meant to fulfil the needs of several researchers also avoiding duplication of effort in writing custom implementations. CoSimPy is under constant development and aims to represent a coworking environment where scientists can implement additional methods whose sharing can represent an advantage for the community. Finally, even if CoSimPy is designed with special focus on MRI, it represents an efficient and practical tool potentially employable wherever electronic devices made of radiative and circuitry components are involved.

Rapid safety assessment and mitigation of radiofrequency induced implant heating using small root mean square sensors and the sensor matrix Qs.

PURPOSE: Rapid detection and mitigation of radiofrequency (RF)-induced implant heating during MRI based on small and low-cost embedded sensors. THEORY AND METHODS: A diode and a thermistor are embedded at the tip of an elongated mock implant. RF-induced voltages or temperature change measured by these root mean square (RMS) sensors are used to construct the sensor Q-Matrix (QS ). Hazard prediction, monitoring and parallel transmit (pTx)-based mitigation using these sensors is demonstrated in benchtop measurements at 300 MHz and within a 3T MRI. RESULTS: QS acquisition and mitigation can be performed in <20 ms demonstrating real-time capability. The acquisitions can be performed using safe low powers (<3 W) due to the high reading precision of the diode (126 µV) and thermistor (26 µK). The orthogonal projection method used for pTx mitigation was able to reduce the induced signals and temperatures in all 155 investigated locations. Using the QS approach in a pTx capable 3T MRI with either a two-channel body coil or an eight-channel head coil, RF-induced heating was successfully assessed, monitored and mitigated while the image quality outside the implant region was preserved. CONCLUSION: Small (<1.5 mm3 ) and low-cost (<1 €) RMS sensors embedded in an implant can provide all relevant information to predict, monitor and mitigate RF-induced heating in implants, while preserving image quality. The proposed pTx-based QS approach is independent of simulations or in vitro testing and therefore complements these existing safety assessments.

The anesthetic approach for endovascular recanalization therapy depends on the lesion site in acute ischemic stroke.

PURPOSE: Endovascular therapy (EVT) of large-vessel occlusion in acute ischemic stroke (AIS) may be performed in general anesthesia (GA) or conscious sedation (CS). We intended to determine the contribution of ischemic cerebral lesion sites on the physician's decision between GA and CS using voxel-based lesion symptom mapping (VLSM). METHODS: In a prospective local database, we sought patients with documented AIS and EVT. Age, stroke severity, lesion volume, vigilance, and aphasia scores were compared between EVT patients with GA and CS. The ischemic lesions were analyzed on CT or MRI scans and transformed into stereotaxic space. We determined the lesion overlap and assessed whether GA or CS is associated with specific cerebral lesion sites using the voxel-wise Liebermeister test. RESULTS: One hundred seventy-nine patients with AIS and EVT were included in the analysis. The VLSM analysis yielded associations between GA and ischemic lesions in the left hemispheric middle cerebral artery territory and posterior circulation areas. Stroke severity and lesion volume were significantly higher in the GA group. The prevalence of aphasia and aphasia severity was significantly higher and parameters of vigilance lower in the GA group. CONCLUSIONS: The VLSM analysis showed associations between GA and ischemic lesions in the left hemispheric middle cerebral artery territory and posterior circulation areas including the thalamus that are known to cause neurologic deficits, such as aphasia or compromised vigilance, in AIS-patients with EVT. Our data suggest that higher disability, clinical impairment due to neurological deficits like aphasia, or reduced alertness of affected patients may influence the physician's decision on using GA in EVT.

SAVE score with lactate modification predicts in-hospital mortality in patients with ongoing cardiac arrest during VA-ECMO cannulation.

The survival after veno-arterial extracorporeal membrane oxygenation score and its lactate modification predict in-hospital mortality in patients based on pre-extracorporeal membrane oxygenation variables. Cardiac arrest history is a significant variable in these scores; however, patients with ongoing cardiac arrest during cannulation were excluded from these models. The goal of this study is to validate the survival after veno-arterial extracorporeal membrane oxygenation score with a lactate modification among patients with ongoing cardiac arrest. In our study, the survival after veno-arterial extracorporeal membrane oxygenation score predicted mortality in all patients, but did so with higher discrimination among ongoing cardiac arrest patients with a lactate modification.

Survival and Outcomes After Cardiac Arrest With VA-ECMO Rescue Therapy.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) use in patients with cardiac arrest is increasing. Utilization remains variable between centers using ECMO as a rescue therapy or early protocolized extracorporeal cardiopulmonary resuscitation. METHODS: Single-center, retrospective evaluation of cardiac arrest with cardiopulmonary resuscitation and rescue ECMO support from 2011 through 2019. Study objectives included survival, non-neurologic, and neurologic outcomes; validation of the SAVE and modified SAVE (mSAVE) scores for survival and favorable neurologic outcome; and predictive factor identification in cardiac arrest with ECMO rescue therapy. RESULTS: Eighty-nine patients were included. In-hospital survival was 38.2% and median CPC score was 2. Survivors had lower BMI (27.9 ±â€Š4.2 kg/m2 vs. 32.3 ±â€Š7.5 kg/m2, P = 0.003), less obesity (BMI ≥ 30 kg/m2) (26.5% vs. 49.1%, P = 0.035), shorter CPR duration (35.5 ±â€Š31.7 m vs. 58.0 ±â€Š49.5 m, P = 0.019), more tracheostomy (38.2% vs. 7.3%, P < 0.001), and less renal replacement therapy (RRT) (17.6% vs. 38.2%, P = 0.031). Patients with a favorable neurologic outcome had lower body weight (86.2 ±â€Š17.9 kg vs. 98.1 ±â€Š19.4 kg, P = 0.010), lower BMI (28.1 ±â€Š4.5 kg/m2 vs. 33.9 ±â€Š7.9 kg/m2, P < 0.001), and less obesity (29.7% vs. 56.3%, P = 0.026). mSAVE score predicted in-hospital survival (OR 1.11; 95%CI 1.03-1.19; P = 0.004) and favorable neurologic outcome (OR 1.11; 1.03-1.20; P = 0.009). Multivariate analysis for in-hospital survival included mSAVE, BMI, CPR-time, tracheostomy, and RRT (c-statistic: 0.864). Favorable neurologic outcome included mSAVE and BMI (c-statistic: 0.805). CONCLUSIONS: mSAVE, BMI, RRT, and tracheostomy are predictors of in-hospital survival and mSAVE and BMI are predictors of favorable neurologic outcome in cardiac arrest with ECMO rescue therapy.

Resolution of the paradox of the diamagnetic effect on the Kibble coil.

Employing very simple electro-mechanical principles known from classical physics, the Kibble balance establishes a very precise and absolute link between quantum electrical standards and macroscopic mass or force measurements. The success of the Kibble balance, in both determining fundamental constants (h, [Formula: see text], e) and realizing a quasi-quantum mass in the 2019 newly revised International System of Units, relies on the perfection of Maxwell's equations and the symmetry they describe between Lorentz's force and Faraday's induction, a principle and a symmetry stunningly demonstrated in the weighing and velocity modes of Kibble balances to within [Formula: see text], with nothing but imperfect wires and magnets. However, recent advances in the understanding of the current effect in Kibble balances reveal a troubling paradox. A diamagnetic effect, a force that does not cancel between mass-on and mass-off measurement, is challenging balance maker's assumptions of symmetry at levels that are almost two orders of magnitude larger than the reported uncertainties. The diamagnetic effect, if it exists, shows up in weighing mode without a readily apparent reciprocal effect in the velocity mode, begging questions about systematic errors at the very foundation of the new measurement system. The hypothetical force is caused by the coil current changing the magnetic field, producing an unaccounted force that is systematically modulated with the weighing current. Here we show that this diamagnetic force exists, but the additional force does not change the equivalence between weighing and velocity measurements. We reveal the unexpected way that symmetry is preserved and show that for typical materials and geometries the total relative effect on the measurement is [Formula: see text].