Accelerated 3D metabolite T1 mapping of the brain using variable-flip-angle SPICE.

PURPOSE: To develop a practical method to enable 3D T1 mapping of brain metabolites. THEORY AND METHODS: Due to the high dimensionality of the imaging problem underlying metabolite T1 mapping, measurement of metabolite T1 values has been currently limited to a single voxel or slice. This work achieved 3D metabolite T1 mapping by leveraging a recent ultrafast MRSI technique called SPICE (spectroscopic imaging by exploiting spatiospectral correlation). The Ernst-angle FID MRSI data acquisition used in SPICE was extended to variable flip angles, with variable-density sparse sampling for efficient encoding of metabolite T1 information. In data processing, a novel generalized series model was used to remove water and subcutaneous lipid signals; a low-rank tensor model with prelearned subspaces was used to reconstruct the variable-flip-angle metabolite signals jointly from the noisy data. RESULTS: The proposed method was evaluated using both phantom and healthy subject data. Phantom experimental results demonstrated that high-quality 3D metabolite T1 maps could be obtained and used for correction of T1 saturation effects. In vivo experimental results showed metabolite T1 maps with a large spatial coverage of 240 × 240 × 72 mm3 and good reproducibility coefficients (< 11%) in a 14.5-min scan. The metabolite T1 times obtained ranged from 0.99 to 1.44 s in gray matter and from 1.00 to 1.35 s in white matter. CONCLUSION: We successfully demonstrated the feasibility of 3D metabolite T1 mapping within a clinically acceptable scan time. The proposed method may prove useful for both T1 mapping of brain metabolites and correcting the T1-weighting effects in quantitative metabolic imaging.

Neurosurgical Implant Safety in 7 T MRI: A Scoping Review.

The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across neurosurgical and neurologic specialties. However, few neurosurgical-related implants have been tested for safety at 7 T, limiting its use in patients with cranial fixation, shunt placements, and other implants. Implant safety can be determined via the American Society for Testing Materials International (ASTM) guidelines. To assess the current state of neurosurgical implant safety at 7 T, a systematic search was performed using PubMed, MEDLINE, Web of Knowledge, and citation matching. Studies written in English that included at least one neurosurgical implant and at least one safety outcome were included. Data were extracted for implant studied, implant composition, deflection angle, torque, temperature change, and ASTM guidelines followed. PRISMA reporting guidelines for scoping reviews were followed. Overall, 18 studies consisting of 45 unique implants were included. Implants included cranial fixation devices, aneurysm clips, spinal rods, pedicle screws, ventriculoperitoneal (VP) shunts, deep brain stimulation devices, and electroencephalogram (EEG) caps and electrodes. Cranial fixation devices, deep brain stimulation devices, spinal rods, and pedicle screws are likely 7 T MRI compatible based on outcomes reported. Aneurysm clips and EEG devices had variable safety outcomes. The VP shunts studied lost functionality after 7 T MRI exposure. We identified several implants that are likely compatible with 7 T MRI. Given the growth in 7 T imaging and expansion of the technology, neurosurgical implants should be constructed with the aforementioned considerations. Caution must be taken with all implants, especially aneurysm clips, programmable VP shunts, and EEG recording devices. It is also noteworthy that several implant testing reports did not report following ASTM standards. This scoping review seeks to concisely summarize all neurosurgical-related implants that have been tested for safety in 7 T MRI. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Simultaneous QSM and metabolic imaging of the brain using SPICE: Further improvements in data acquisition and processing.

PURPOSE: To achieve high-resolution mapping of brain tissue susceptibility in simultaneous QSM and metabolic imaging. METHODS: Simultaneous QSM and metabolic imaging was first achieved using SPICE (spectroscopic imaging by exploiting spatiospectral correlation), but the QSM maps thus obtained were at relatively low-resolution (2.0 × 3.0 × 3.0 mm3 ). We overcome this limitation using an improved SPICE data acquisition method with the following novel features: 1) sampling (k, t)-space in dual densities, 2) sampling central k-space fully to achieve nominal spatial resolution of 3.0 × 3.0 × 3.0 mm3 for metabolic imaging, and 3) sampling outer k-space sparsely to achieve spatial resolution of 1.0 × 1.0 × 1.9 mm3 for QSM. To keep the scan time short, we acquired spatiospectral encodings in echo-planar spectroscopic imaging trajectories in central k-space but in CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration) trajectories in outer k-space using blipped phase encodings. For data processing and image reconstruction, a union-of-subspaces model was used, effectively incorporating sensitivity encoding, spatial priors, and spectral priors of individual molecules. RESULTS: In vivo experiments were carried out to evaluate the feasibility and potential of the proposed method. In a 6-min scan, QSM maps at 1.0 × 1.0 × 1.9 mm3 resolution and metabolic maps at 3.0 × 3.0 × 3.0 mm3 nominal resolution were obtained simultaneously. Compared with the original method, the QSM maps obtained using the new method reveal fine-scale brain structures more clearly. CONCLUSION: We demonstrated the feasibility of achieving high-resolution QSM simultaneously with metabolic imaging using a modified SPICE acquisition method. The improved capability of SPICE may further enhance its practical utility in brain mapping.

Accelerating T2 mapping of the brain by integrating deep learning priors with low-rank and sparse modeling.

PURPOSE: To accelerate T2 mapping with highly sparse sampling by integrating deep learning image priors with low-rank and sparse modeling. METHODS: The proposed method achieves high-speed T2 mapping by highly sparsely sampling (k, TE)-space. Image reconstruction from the undersampled data was done by exploiting the low-rank structure and sparsity in the T2 -weighted image sequence and image priors learned from training data. The image priors for a single TE were generated from the public Human Connectome Project data using a tissue-based deep learning method; the image priors were then transferred to other TEs using a generalized series-based method. With these image priors, the proposed reconstruction method used a low-rank model and a sparse model to capture subject-dependent novel features. RESULTS: The proposed method was evaluated using experimental data obtained from both healthy subjects and tumor patients using a turbo spin-echo sequence. High-quality T2 maps at the resolution of 0.9 × 0.9 × 3.0 mm3 were obtained successfully from highly undersampled data with an acceleration factor of 8. Compared with the existing compressed sensing-based methods, the proposed method produced significantly reduced reconstruction errors. Compared with the deep learning-based methods, the proposed method recovered novel features better. CONCLUSION: This paper demonstrates the feasibility of learning T2 -weighted image priors for multiple TEs using tissue-based deep learning and generalized series-based learning. A new method was proposed to effectively integrate these image priors with low-rank and sparse modeling to reconstruct high-quality images from highly undersampled data. The proposed method will supplement other acquisition-based methods to achieve high-speed T2 mapping.

Maternal Dietary Intake of Omega-3 Fatty Acids Correlates Positively with Regional Brain Volumes in 1-Month-Old Term Infants.

Maternal nutrition is an important factor for infant neurodevelopment. However, prior magnetic resonance imaging (MRI) studies on maternal nutrients and infant brain have focused mostly on preterm infants or on few specific nutrients and few specific brain regions. We present a first study in term-born infants, comprehensively correlating 73 maternal nutrients with infant brain morphometry at the regional (61 regions) and voxel (over 300 000 voxel) levels. Both maternal nutrition intake diaries and infant MRI were collected at 1 month of life (0.9 ± 0.5 months) for 92 term-born infants (among them, 54 infants were purely breastfed and 19 were breastfed most of the time). Intake of nutrients was assessed via standardized food frequency questionnaire. No nutrient was significantly correlated with any of the volumes of the 61 autosegmented brain regions. However, increased volumes within subregions of the frontal cortex and corpus callosum at the voxel level were positively correlated with maternal intake of omega-3 fatty acids, retinol (vitamin A) and vitamin B12, both with and without correction for postmenstrual age and sex (P < 0.05, q < 0.05 after false discovery rate correction). Omega-3 fatty acids remained significantly correlated with infant brain volumes after subsetting to the 54 infants who were exclusively breastfed, but retinol and vitamin B12 did not. This provides an impetus for future larger studies to better characterize the effect size of dietary variation and correlation with neurodevelopmental outcomes, which can lead to improved nutritional guidance during pregnancy and lactation.

System-Specific Patterns of Thalamocortical Connectivity in Early Brain Development as Revealed by Structural and Functional MRI.

The normal development of thalamocortical connections plays a critical role in shaping brain connectivity in the prenatal and postnatal periods. Recent studies using advanced magnetic resonance imaging (MRI) techniques in neonates and infants have shown that abnormal thalamocortical connectivity is associated with adverse neurodevelopmental outcomes. However, all these studies have focused on a single neuroimaging modality, overlooking the dynamic relationship between structure and function at this early stage. Here, we study the relationship between structural and functional thalamocortical connectivity patterns derived from healthy full-term infants scanned with diffusion-weighted MRI and resting-state functional MRI within the first weeks of life (mean gestational age = 39.3 ± 1.2 weeks; age at scan = 24.2 ± 7.9 days). Our results show that while there is, in general, good spatial agreement between both MRI modalities, there are regional variations that are system-specific: regions involving primary-sensory cortices exhibit greater structural/functional overlap, whereas higher-order association areas such as temporal and posterior parietal cortices show divergence in spatial patterns of each modality. This variability illustrates the complementarity of both modalities and highlights the importance of multimodal approaches.

PREVALENCE OF VITREOMACULAR ADHESION IN PATIENTS WITHOUT MACULOPATHY OLDER THAN 40 YEARS.

PURPOSE: To determine the prevalence and factors influencing vitreomacular adhesion (VMA) or vitreomacular traction (VMT) in subjects without maculopathy older than age 40 years. METHODS: In a prospective cross-sectional study, 1,950 eyes in 1,090 participants aged 40 to 89 years representing various ethnic groups from 14 centers in the United States underwent a comprehensive eye examination, including spectral domain optical coherence tomography. A team of independent, masked readers classified the presence or absence of VMA/VMT on spectral domain optical coherence tomography based on the International Vitreomacular Traction Study Group rubric. RESULTS: Across all eyes, the prevalence of VMA or VMT was 39% or 1%, respectively. For every 1-year increase in age, there was a statistically significant 7% decreased odds of having VMA or VMT (95% confidence interval [CI]: 0.89-0.96; P < 0.001), whereas African Americans had 55% significantly reduced odds of having VMA or VMT when than whites (95% CI: 0.23-0.90; P = 0.025). Vitreomacular adhesion >1,500 µm was significantly more likely than VMA <1,500 µm in younger adults (95% CI: 0.70-0.86; P < 0.001), hyperopes versus emmetropes (95% CI: 1.49-35.9; P = 0.01), primary eye care versus tertiary practices (95% CI: 0.03-0.92; P = 0.04), and patients without hyperlipidemia (95% CI: 0.04-0.83; P = 0.03). CONCLUSION: Vitreomacular adhesion is highly prevalent among middle-aged adults. Diagnostic screening with spectral domain optical coherence tomography may help to accurately detect VMA or VMT, prompting routine monitoring and timely therapeutic intervention.

Analysis of Patient Visits and Collections After Opening a Satellite Pediatric Emergency Department.

OBJECTIVE: Satellite pediatric emergency departments (PEDs) have emerged as a strategy to increase patient capacity. We sought to determine the impact on patient visits, physician fee collections, and value of emergency department (ED) time at the primary PED after opening a nearby satellite PED. We also illustrate the spatial distribution of patient demographics and overlapping catchment areas for the primary and satellite PEDs using geographical information system. METHODS: A structured, financial retrospective review was conducted. Aggregate patient demographic data and billing data were collected regarding physician fee charges, collections, and patient visits for both PEDs. All ED visits from January 2009 to December 2013 were analyzed. Geographical information system mapping using ArcGIS mapped ED patient visits. RESULTS: Patient visits at the primary PED were 53,050 in 2009 before the satellite PED opened. The primary PED visits increased after opening the satellite PED to 55,932 in 2013. The satellite PED visits increased to 21,590 in 2013. Collections per visit at the primary PED decreased from $105.13 per visit in 2011 to $86.91 per visit in 2013. Total collections at the satellite PED decreased per visit from $155.41 per visit in 2011 to $128.53 per visit in 2013. CONCLUSIONS: After opening a nearby satellite PED, patient visits at the primary PED did not substantially decrease, suggesting that there was a previously unrecognized demand for PED services. The collections per ED visit were greater at the satellite ED, likely due to a higher collection rate.

Cost-effectiveness Analysis of Contralateral Prophylactic Mastectomy Compared to Unilateral Mastectomy with Routine Surveillance for Unilateral, Sporadic Breast Cancer.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) rates in younger women with unilateral breast cancer have more than doubled. Studies of cost and quality of life of the procedure remain inconclusive. METHODS: A cost-effectiveness analysis using a decision-tree model in TreeAge Pro 2015 was used to compare long-term costs and quality of life following unilateral mastectomy (UM) with routine surveillance versus CPM for sporadic breast cancer in women aged 45 years. A 10-year risk period for contralateral breast cancer (CBC), reconstruction, wound complications, cost of routine surveillance, and treatment for CBC were used to estimate accrued costs. In addition, a societal perspective was used to estimate quality-adjusted life years (QALYs) following either treatment for a period of 30 years. Medical costs were obtained from the 2014 Medicare physician fee schedule and event probabilities were taken from recent literature. RESULTS: The mean cost of UM with surveillance was $14,141 and CPM was $20,319. Treatment with CPM resulted in $6178 more in costs but equivalent QALYs (17.93) compared with UM over 30 years of follow-up. Even with worst-case scenario and varying assumptions, CPM is dominated by UM in terms of cost and quality. CONCLUSIONS: From this refined model, UM with routine surveillance costs less and provides an equivalent quality of life. Patients undergoing CPM may eliminate the anxiety of routine surveillance, but they face the burden of higher lifetime medical costs.

The Cardiovascular Intensive Care Unit-An Evolving Model for Health Care Delivery.

Prior to the advent of the coronary care unit (CCU), patients having an acute myocardial infarction (AMI) were managed on the general medicine wards with reported mortality rates of greater than 30%. The first CCUs are believed to be responsible for reducing mortality attributed to AMI by as much as 40%. This drastic improvement can be attributed to both advances in medical technology and in the process of health care delivery. Evolving considerably since the 1960s, the CCU is now more appropriately labeled as a cardiac intensive care unit (CICU) and represents a comprehensive system designed for the care of patients with an array of advanced cardiovascular disease, an entity that reaches far beyond its early association with AMI. Grouping of patients by diagnosis to a common physical space, dedicated teams of health care providers, as well as the development and implementation of evidence-based treatment algorithms have resulted in the delivery of safer, more efficient care, and most importantly better patient outcomes. The CICU serves as a platform for an integrated, team-based patient care delivery system that addresses a broad spectrum of patient needs. Lessons learned from this model can be broadly applied to address the urgent need to improve outcomes and efficiency in a variety of health care settings.

Outer Retinal Tubulation: A Case Series.

PURPOSE: The advent of spectral domain optical coherence tomography has led to superb imaging capabilities in addition to enhanced visualization of the retinal layers. Such advancements have led to the identification of a variety of new retinal conditions, including outer retinal tubulations (ORTs). ORTs are ovoid hyporeflective spaces located in the outer retina. The pathogenesis is unclear but seems to involve sublethal injury to the photoreceptors leading to a compensatory reorganization of the photoreceptor layer with the neighboring ellipsoid zone resulting in a hyperreflective border surrounding a central lumen. Most ORTs have been linked to wet age-related macular degeneration; however, these peculiar structures are now seen in a myriad of retinal disorders. CASE REPORTS: Our cases will highlight the wide variety of clinical presentations associated with outer retinal tubulations. The clinical presentations include two cases of wet age-related macular degeneration, a case of presumed ocular histoplasmosis syndrome, a case of central areolar choroidal dystrophy, and a case of pathological myopia. CONCLUSIONS: By correctly differentiating outer retinal tubulations from other masqueraders, unnecessary referrals and interventions can be minimized. Understanding the various disease entities associated with outer retinal tubulation could give further insight into the mechanism and formation of these structures.

Recommendations for real-time speech MRI.

Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech.

Perinatal choline deficiency delays brain development and alters metabolite concentrations in the young pig.

OBJECTIVES: Adequate choline supply during the perinatal period is critical for proper brain formation, when robust neurogenesis and neuronal maturation occur. Therefore, the objective of this study was to examine the impact of perinatal choline status on neurodevelopment. METHODS: Sows were fed a choline-deficient (CD) or choline-sufficient (CS) diet during the last half of the gestational period. At 2 days of age, piglets from sows within each prenatal treatment group were further stratified into postnatal treatment groups and provided either a CD or CS milk replacer, resulting in four treatment groups. At 30 days of age, piglets underwent magnetic resonance imaging (MRI) procedures to analyze structural and metabolite differences. RESULTS: Single-voxel spectroscopy (SVS) analysis revealed postnatally CS piglets had higher (P < 0.001) concentrations of glycerophosphocholine-phosphocholine than postnatally CD piglets. Volumetric analysis indicated smaller (P < 0.006) total brain volumes in prenatally CD piglets compared with prenatally CS piglets. Differences (P < 0.05) in the corpus callosum, pons, midbrain, thalamus, and right hippocampus, were observed as larger region-specific volumes proportional to total brain size in prenatally CD piglets compared with CS piglets. Diffusion tensor imaging (DTI) suggested interactions (P < 0.05) between prenatal and postnatal choline status in fractional anisotropy values of the thalamus and right hippocampus. Prenatally CS piglets had lower cerebellar radial diffusivity (P = 0.045) compared with prenatally CD piglets. DISCUSSION: This study demonstrates that prenatal choline deficiency has profound effects by delaying neurodevelopment as evidenced by structural and metabolic MRI assessments.

Impact of cardiac resynchronization therapy on clinical outcomes in patients with continuous-flow left ventricular assist devices.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) can improve survival in left ventricular assist device (LVAD) recipients. However, the impact of cardiac resynchronization therapy (CRT-D) on outcomes in continuous-flow left ventricular assist device (CF-LVAD) patients is not known. We sought to determine if CRT-D improved clinical outcomes in CF-LVAD patients compared with ICDs alone. METHODS AND RESULTS: Sixty-one consecutive CF-LVAD patients with an ICD or CRT-D were evaluated. Impacts of CRT-D on mortality, all-cause hospitalization, and incidence of atrial (AA) and ventricular (VA) arrhythmias after LVAD implantation was compared with patients with ICD alone. Of the 61 LVAD patients, 31 (age 59.8 ± 16 years, 84% male) had CRT-D and 30 (age 57.2 ± 13 years, 74% male) had ICD. Before LVAD implantation, no significant differences were noted between the groups in demographic and clinical characteristics, LVAD indications, and incidence of AA and VA. Over 682 ± 45 days of LVAD support, 8 patients (25.8%) died in the CRT-D arm versus 5 (16.7%) in the ICD arm (P = .35). No differences were noted between the CRT-D and ICD groups in all-cause (96.8 vs 93.3%; P = .63) and HF (19.4 vs 26.7%; P = .78) hospitalizations, left ventricular (LV) end-diastolic diameter (6.4 ± 1.5 vs 6.2 ± 1.1 cm, P = .47), and incidence of AA (35.4% vs 33.3%; P = .80), VA (29% vs 26.6%; P = .86), and ICD shocks (22.6% vs 16.7%; P = .93). Beta-blocker and antiarrhythmic drug use after LVAD implantation was similar in both groups. CONCLUSIONS: In patients with refractory HF who received CF-LVADs, CRT-D, compared with ICD, did not significantly improve mortality, all-cause hospitalization, LV dimensions, and incidence of AA and VA.

Accelerated, physics-inspired inference of skeletal muscle microstructure from diffusion-weighted MRI.

Muscle health is a critical component of overall health and quality of life. However, current measures of skeletal muscle health take limited account of microstructural variations within muscle, which play a crucial role in mediating muscle function. To address this, we present a physics-inspired, machine learning-based framework for the non-invasive estimation of microstructural organization in skeletal muscle from diffusion-weighted MRI (dMRI) in an uncertainty-aware manner. To reduce the computational expense associated with direct numerical simulations of dMRI physics, a polynomial meta-model is developed that accurately represents the input/output relationships of a high-fidelity numerical model. This meta-model is used to develop a Gaussian process (GP) model that provides voxel-wise estimates and confidence intervals of microstructure organization in skeletal muscle. Given noise-free data, the GP model accurately estimates microstructural parameters. In the presence of noise, the diameter, intracellular diffusion coefficient, and membrane permeability are accurately estimated with narrow confidence intervals, while volume fraction and extracellular diffusion coefficient are poorly estimated and exhibit wide confidence intervals. A reduced-acquisition GP model, consisting of one-third the diffusion-encoding measurements, is shown to predict parameters with similar accuracy to the original model. The fiber diameter and volume fraction estimated by the reduced GP model is validated via histology, with both parameters accurately estimated, demonstrating the capability of the proposed framework as a promising non-invasive tool for assessing skeletal muscle health and function.

Autonomic Effects of Pulsed Field vs Thermal Ablation for Treating Atrial Fibrillation: Subanalysis of ADVENT.

BACKGROUND: Autonomic denervation is an ancillary phenomenon during thermal ablation of atrial fibrillation (AF), that may have synergistic effects on symptomatic improvement and long-term freedom from AF. Pulsed field ablation (PFA), a nonthermal ablation modality, was noninferior to thermal ablation in treating AF; however, PFA's relative myocardial selectivity may minimize autonomic effects. OBJECTIVES: This study sought to compare heart rate (HR) and heart rate variability (HRV) metrics as markers of autonomic function after ablation using PFA vs thermal ablation. METHODS: ADVENT (FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation) was a randomized pivotal study comparing PFA (pentaspline catheter) with thermal ablation (radiofrequency [RF] or cryoballoon [CB]) for treating paroxysmal AF. Baseline HR was acquired from a pre-ablation 12-lead electrocardiogram, whereas follow-up HRs, as well as HRV (standard deviation of all normal to normal RR intervals, standard deviation of 5-minute average RR intervals) metrics, were derived from 72-hour Holter monitors at 6 and 12 months. RESULTS: This study included 379 paroxysmal AF patients undergoing PFA (n = 194) or thermal ablation (n = 185; n = 102 RF, n = 83 CB) completing 6- and 12-month Holter monitoring. Compared with PFA, thermal patients had significantly greater increases in HR from baseline to 6 months (ΔHR; 10.1 vs 5.9 beats/min; P = 0.02) and 12 months (ΔHR; 8.8 vs 5.2 beats/min; P = 0.03). This increase in HR at 6 and 12 months was similar between CB and RF (P = 0.94 and 0.83, respectively). HRV, both standard deviation of all normal to normal RR intervals and standard deviation of 5-minute average RR intervals, were significantly lower at both 6 and 12 months after thermal ablation compared with PFA (P < 0.01). CONCLUSIONS: PFA's effect on the autonomic nervous system was attenuated compared with thermal ablation. Whether this affects long-term freedom from AF or symptomatic bradycardia/pauses after AF ablation requires further study.

Pulsed Field vs Conventional Thermal Ablation for Paroxysmal Atrial Fibrillation: Recurrent Atrial Arrhythmia Burden.

BACKGROUND: The ADVENT randomized trial revealed no significant difference in 1-year freedom from atrial arrhythmias (AA) between thermal (radiofrequency/cryoballoon) and pulsed field ablation (PFA). However, recent studies indicate that the postablation AA burden is a better predictor of clinical outcomes than the dichotomous endpoint of 30-second AA recurrence. OBJECTIVES: The goal of this study was to determine: 1) the impact of postablation AA burden on outcomes; and 2) the effect of ablation modality on AA burden. METHODS: In ADVENT, symptomatic drug-refractory patients with paroxysmal atrial fibrillation underwent PFA or thermal ablation. Postablation transtelephonic electrocardiogram monitor recordings were collected weekly or for symptoms, and 72-hour Holters were at 6 and 12 months. AA burden was calculated from percentage AA on Holters and transtelephonic electrocardiogram monitors. Quality-of-life assessments were at baseline and 12 months. RESULTS: From 593 randomized patients (299 PFA, 294 thermal), using aggregate PFA/thermal data, an AA burden exceeding 0.1% was associated with a significantly reduced quality of life and an increase in clinical interventions: redo ablation, cardioversion, and hospitalization. There were more patients with residual AA burden <0.1% with PFA than thermal ablation (OR: 1.5; 95% CI: 1.0-2.3; P = 0.04). Evaluation of outcomes by baseline demographics revealed that patients with prior failed class I/III antiarrhythmic drugs had less residual AA burden after PFA compared to thermal ablation (OR: 2.5; 95% CI: 1.4-4.3; P = 0.002); patients receiving only class II/IV antiarrhythmic drugs pre-ablation had no difference in AA burden between ablation groups. CONCLUSIONS: Compared with thermal ablation, PFA more often resulted in an AA burden less than the clinically significant threshold of 0.1% burden. (The FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation [ADVENT]; NCT04612244).

Simultaneous Mapping of Water Diffusion Coefficients and Metabolite Distributions of the Brain Using MR Spectroscopic Imaging Without Water Suppression.

OBJECTIVE: To simultaneously map water diffusion coefficients and metabolite distributions of the brain in magnetic resonance spectroscopic imaging (MRSI) experiments within a clinically feasible time. METHODS: A diffusion-preparation module was introduced in water-unsuppressed MRSI acquisition sequence to generate diffusion weighting of the water signals. Fast spatiospectral encodings were achieved using echo-planar spectroscopic imaging readouts with blipped phase encodings for sparse sampling. Navigator signals were embedded in the data acquisition sequence, which were used for detection of data corrupted by physiological motion in the diffusion preparation period. In data processing, a novel model-based method was developed to effectively use sparse (k, t)-space spectroscopic signals for reconstruction of the spatial distributions of water diffusion coefficients and metabolite concentrations. RESULTS: Both phantom experiments and in vivo experiments were carried out to evaluate the feasibility and performance of the proposed method. In an 8-minute scan, diffusion weighted images and apparent diffusion coefficients map at 2.0×1.0×1.0 mm3 were obtained simultaneously with metabolite maps at 2.0×3.0×3.0 mm3 nominal resolution. CONCLUSION: We demonstrated the feasibility of using the unsuppressed water signals from MRSI experiments to map the water diffusion coefficients of brain tissues and proposed a novel method to achieve simultaneous mapping of water diffusion coefficients and metabolite distributions. SIGNIFICANCE: The proposed method provides a unique imaging tool for simultaneous diffusion and metabolic imaging. This method is expected to be useful for various brain imaging applications.

Rhythmia zero-fluoroscopy workflow with high-power, short-duration ablation: retrospective analysis of procedural data.

BACKGROUND: Fluoroscopy is commonly used during atrial fibrillation (AF) ablation to guide catheter navigation and placement. Technology improvements have significantly reduced fluoroscopy time, and subsequent radiation dose, necessary to perform successful ablations. However, there is still no amount of radiation exposure known to be completely safe. The aim of this manuscript is to describe a detailed zero-fluoroscopy RHYTHMIA HDx workflow for AF ablation. METHODS: This was an observational, single-center experience to describe the technique, acute procedural success, and safety using a novel zero-fluoroscopy workflow with the RHYTHMIA HDx mapping system and intracardiac echocardiography (ICE). Seventy-two consecutive patients undergoing de novo or redo AF ablation were retrospectively analyzed. Venous access was guided with ultrasound. ICE combined with the mapping system's magnetic tracking and sheath detection was used for precise catheter placement in the coronary sinus, at the transseptal puncture, and in the left atrium. A high-power, short-duration ablation strategy guided by local impedance was used. Pulmonary vein isolation was performed or touched up for all patients with additional lines added at the operator's discretion. RESULTS: Using this zero-fluoroscopy workflow, all patients achieved acute isolation with no significant procedure-related complications. Average procedure time was 73.7 ± 16.2 min, which included persistent (58%) and paroxysmal (42%) AF cases, and no procedures required conversion to fluoroscopy. CONCLUSIONS: In this experience, a zero-fluoroscopy workflow using the RHYTHMIA HDx mapping system combined with ICE was feasible and safe for ablation in a heterogenous AF population. This approach, in the appropriate patient population, can eliminate radiation exposure to patients and staff.

Increased Breastfeeding Proportion Is Associated with Improved Gross Motor Skills at 3-5 Years of Age: A Pilot Study.

Breastmilk provides key nutrients and bio-active factors that contribute to infant neurodevelopment. Optimizing maternal nutrition could provide further benefit to psychomotor outcomes. Our observational cohort pilot study aims to determine if breastfeeding extent and breastmilk nutrients correlate with psychomotor outcomes at school age. The breastfeeding proportion at 3 months of age and neurodevelopmental outcomes at 3-5 years of age were recorded for 33 typically developing newborns born after uncomplicated pregnancies. The association between categorical breastfeeding proportion and neurodevelopmental outcome scores was determined for the cohort using a Spearman correlation with and without the inclusion of parental factors. Vitamin E and carotenoid levels were determined in breastmilk samples from 14 of the mothers. After the inclusion of parental education and income as covariates, motor skill scores positively correlated with breastmilk contents of α-tocopherol (Spearman coefficient 0.88, p-value = 0.02), translutein (0.98, p-value = 0.0007), total lutein (0.92, p-value = 0.01), and zeaxanthin (0.93, p-value = 0.0068). Problem solving skills negatively correlated with the levels of the RSR enantiomer of α-tocopherol (-0.86, p-value = 0.03). Overall, higher exposure to breastfeeding was associated with improved gross motor and problem-solving skills at 3-5 years of age. The potential of α-tocopherol, lutein, and zeaxanthin intake to provide neurodevelopmental benefit is worthy of further investigation.