Computationally Efficient IMplicit Training Strategy for UNrolled NEtworks (IMUNNE): A preliminary analysis using accelerated real-time cardiac cine MRI.

Objective: Highly-undersampled, dynamic MRI reconstruction, particularly in multi-coil scenarios, is a challenging inverse problem. Unrolled networks achieve state-of-the-art performance in MRI reconstruction but suffer from long training times and extensive GPU memory cost.

Methods: In this work, we propose a novel training strategy for IMplicit UNrolled NEtworks (IMUNNE) for highly-undersampled, multi-coil dynamic MRI reconstruction.

Ultra-rapid, Free-breathing, Real-time Cardiac Cine MRI Using GRASP Amplified with View Sharing and KWIC Filtering.

Purpose To achieve ultra-high temporal resolution (approximately 20 msec) in free-breathing, real-time cardiac cine MRI using golden-angle radial sparse parallel (GRASP) reconstruction amplified with view sharing (VS) and k-space-weighted image contrast (KWIC) filtering. Materials and Methods Fourteen pediatric patients with congenital heart disease (mean age [SD], 9 years ± 2; 13 male) and 10 adult patients with arrhythmia (mean age, 62 years ± 8; nine male) who underwent both standard breath-hold cine and free-breathing real-time cine using GRASP were retrospectively identified. To achieve high temporal resolution, each time frame was reconstructed using six radial spokes, corresponding to acceleration factors ranging from 24 to 32.

GRASP reconstruction amplified with view-sharing and KWIC filtering reduces underestimation of peak velocity in highly-accelerated real-time phase-contrast MRI: A preliminary evaluation in pediatric patients with congenital heart disease.

Purpose: To develop a highly-accelerated, real-time phase contrast (rtPC) MRI pulse sequence with 40 fps frame rate (25 ms effective temporal resolution).

Methods: Highly-accelerated golden-angle radial sparse parallel (GRASP) with over regularization may result in temporal blurring, which in turn causes underestimation of peak velocity. Thus, we amplified GRASP performance by synergistically combining view-sharing (VS) and k-space weighted image contrast (KWIC) filtering.

Direct methane protonic ceramic fuel cells with self-assembled Ni-Rh bimetallic catalyst.

Direct methane protonic ceramic fuel cells are promising electrochemical devices that address the technical and economic challenges of conventional ceramic fuel cells. However, Ni, a catalyst of protonic ceramic fuel cells exhibits sluggish reaction kinetics for CH conversion and a low tolerance against carbon-coking, limiting its wider applications. Herein, we introduce a self-assembled Ni-Rh bimetallic catalyst that exhibits a significantly high CH conversion and carbon-coking tolerance.

Incorporation of view sharing and KWIC filtering into GRASP-Pro improves spatial resolution of single-shot, multi-TI, late gadolinium enhancement MRI.

While single-shot late gadolinium enhancement (LGE) is useful for imaging patients with arrhythmia and/or dyspnea, it produces low spatial resolution. One approach to improve spatial resolution is to accelerate data acquisition using compressed sensing (CS). Our previous work described a single-shot, multi-inversion time (TI) LGE pulse sequence using radial k-space sampling and CS, but over-regularization resulted in significant image blurring that muted the benefits of data acceleration.

The Position and Orientation of the Pulse Generator Affects MRI RF Heating of Epicardial Leads in Children.

Infants and children with congenital heart defects often receive a cardiac implantable electronic device (CIED). Because transvenous access to the heart is difficult in patients with small veins, the majority of young children receive epicardial CIEDs. Unfortunately, however, once an epicardial CIED is placed, patients are no longer eligible to receive magnetic resonance imaging (MRI) exams due to the unknown risk of MRI-induced radiofrequency (RF) heating of the device.

Optimal saturation recovery time for minimizing the underestimation of arterial input function in quantitative cardiac perfusion MRI.

Purpose: The purpose of this study was to determine an optimal saturation-recovery time (TS) for minimizing the underestimation of arterial input function (AIF) in quantitative cardiac perfusion MRI without multiple gadolinium injections per subject.

Methods: We scanned 18 subjects (mean age = 59 ± 14 years, 9/9 males/females) to acquire resting perfusion data and 1 additional subject (age = 38 years, male) to obtain stress-rest perfusion data using a 5-fold accelerated pulse sequence with radial k-space sampling and applied k-space weighted image contrast (KWIC) filters on the same k-space data to retrospectively reconstruct five AIF images with effective TS ranging from 10 to 21.2 ms (2.

Accelerating compressed sensing reconstruction of subsampled radial k-space data using geometrically-derived density compensation.

To accelerate compressed sensing (CS) reconstruction of subsampled radial k-space data using a geometrically-derived density compensation function (gDCF) without significant loss in image quality.We developed a theoretical framework to calculate a gDCF based on Nyquist distance along the radial and circumferential directions of a discrete polar coordinate system. Our gDCF was compared against standard DCF (e.

Mechanism Design of Health Care Blockchain System Token Economy: Development Study Based on Simulated Real-World Scenarios.

Background: Despite the fact that the adoption rate of electronic health records has increased dramatically among high-income nations, it is still difficult to properly disseminate personal health records. Token economy, through blockchain smart contracts, can better distribute personal health records by providing incentives to patients. However, there have been very few studies regarding the particular factors that should be considered when designing incentive mechanisms in blockchain.

A theoretical framework for retrospective correction to the arterial input function in quantitative myocardial perfusion MRI.

Purpose: To develop and evaluate a flexible, Bloch-equation based framework for retrospective correction to the arterial input function (AIF) obtained with quantitative cardiac perfusion pulse sequences.

Methods: Our framework initially calculates the gadolinium concentration [Gd] based on T measurements alone. Next, is estimated from this initial calculation of [Gd] while assuming fast water exchange and using the literature native T and static magnetic field variation (ΔB ) values.

Perspectives of Patients, Health Care Professionals, and Developers Toward Blockchain-Based Health Information Exchange: Qualitative Study.

Background: Although the electronic health record system adoption rate has reached 96% in the United States, implementation and usage of health information exchange (HIE) is still lagging behind. Blockchain has come into the spotlight as a technology to solve this problem. However, there have been no studies assessing the perspectives of different stakeholders regarding blockchain-based patient-centered HIE.

Highly Accelerated Real-Time Free-Breathing Cine CMR for Patients With a Cardiac Implantable Electronic Device.

Rationale And Objectives: To develop a 16-fold accelerated real-time, free-breathing cine cardiovascular magnetic resonance (CMR) pulse sequence with compressed sensing reconstruction and test whether it is capable of producing clinically acceptable summed visual scores (SVS) and accurate left ventricular ejection fraction (LVEF) in patients with a cardiac implantable electronic device (CIED).

Materials And Methods: A 16-fold accelerated real-time cine CMR pulse sequence was developed using gradient echo readout, Cartesian k-space sampling, and compressed sensing. We scanned 13 CIED patients (mean age = 59 years; 9/4 males/females) using clinical standard, breath-hold cine and real-time, free-breathing cine.

Accelerated Wideband Myocardial Perfusion Pulse Sequence with Compressed Sensing Reconstruction for Myocardial Blood Flow Quantification in Patients with a Cardiac Implantable Electronic Device.

Purpose: To develop an accelerated wideband cardiac perfusion pulse sequence and test whether it can produce diagnostically acceptable image quality and whether it can be used to reliably quantify myocardial blood flow (MBF) in patients with a cardiac implantable electronic device (CIED).

Materials And Methods: A fivefold-accelerated wideband perfusion pulse sequence was developed using compressed sensing to sample one arterial input function plane and three myocardial perfusion (MP) planes per heartbeat in patients with a CIED with heart rates as high as 102 beats per minute. Resting perfusion scans were performed in 10 patients with a CIED and in 10 patients with no device as a control group.

Wideband myocardial perfusion pulse sequence for imaging patients with a cardiac implantable electronic device.

Purpose: To develop a wideband cardiac perfusion pulse sequence and test whether it is capable of suppressing image artifacts in patients with a cardiac implantable electronic device (CIED), while not exceeding the specific absorption rate (SAR) limit (2.0 W/kg).

Methods: A wideband perfusion pulse sequence was developed by incorporating a wideband saturation pulse to achieve a good balance between saturation of magnetization and SAR.

Wideband LGE MRI permits unobstructed viewing of myocardial scarring in a patient with an MR-conditional subcutaneous implantable cardioverter-defibrillator.

A subcutaneous implantable cardioverter-defibrillator (S-ICD) is an alternative device for prevention of sudden cardiac death, without any leads within the heart. Patients implanted with any type of ICD may need catheter ablation of ventricular tachycardia (VT) to reduce the overall arrhythmia burden (e.g.

Evaluation of Modified Look-Locker Inversion Recovery and Arrhythmia-Insensitive Rapid Cardiac T1 Mapping Pulse Sequences in Cardiomyopathy Patients.

Objective: The aim of this study was to compare the performance of arrhythmia-insensitive rapid (AIR) and modified Look-Locker inversion recovery (MOLLI) T1 mapping in patients with cardiomyopathies.

Methods: In 58 patients referred for clinical cardiac magnetic resonance imaging at 1.5 T, we compared MOLLI and AIR native and postcontrast T1 measurements.

Optimized AIR and investigational MOLLI cardiac T1 mapping pulse sequences produce similar intra-scan repeatability in patients at 3T.

This study was conducted to improve the precision of arrhythmia-insensitive rapid (AIR) cardiac T1 mapping through pulse sequence optimization and then evaluate the intra-scan repeatability in patients at 3T against investigational modified Look-Locker inversion recovery (MOLLI) T1 mapping. In the first development phase (five human subjects), we implemented and tested centric-pair k-space ordering to suppress image artifacts associated with eddy currents. In the second development phase (15 human subjects), we determined optimal flip angles to reduce the measurement variation in T1 maps.

Wideband arrhythmia-Insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by an implantable-cardioverter-defibrillator.

Purpose: To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD).

Methods: We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz) to achieve uniform T1 weighting in the heart with ICD.

Wideband late gadolinium enhanced magnetic resonance imaging for imaging myocardial scar without image artefacts induced by implantable cardioverter-defibrillator: a feasibility study at 3 T.

Aim: Late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) is a useful tool for facilitating ventricular tachycardia (VT) ablation. Unfortunately, most VT ablation candidates often have prophylactic implantable cardioverter-defibrillator (ICD) and do not undergo cardiac MRI largely due to image artefacts generated by ICD. A prior study has reported success of 'wideband' LGE MRI for imaging myocardial scar without image artefacts induced by ICD at 1.

MOLLI and AIR T1 mapping pulse sequences yield different myocardial T1 and ECV measurements.

Both post-contrast myocardial T1 and extracellular volume (ECV) have been reported to be associated with diffuse interstitial fibrosis. Recently, the cardiovascular magnetic resonance (CMR) field is recognizing that post-contrast myocardial T1 is sensitive to several confounders and migrating towards ECV as a measure of collagen volume fraction. Several recent studies using widely available Modified Look-Locker Inversion-recovery (MOLLI) have reported ECV cutoff values to distinguish between normal and diseased myocardium.

Post-contrast myocardial T(1) and ECV disagree in a longitudinal canine study.

Both post-contrast myocardial T1 and extracellular volume (ECV) measurements have been associated with diffuse interstitial fibrosis. The cardiovascular magnetic resonance (CMR) field is migrating towards ECV, because it is largely insensitive to confounders that affect post-contrast myocardial T1 . Despite the theoretical advantages of myocardial ECV over post-contrast myocardial T1 , systematic experimental studies comparing the two measurements are largely lacking.

Comparison of vessel geometry in bifurcation between normal and diseased segments: intravascular ultrasound analysis.

Objective: To investigate the geometry in bifurcation using intravascular ultrasound (IVUS) analysis.

Methods: We performed quantitative three-dimensional IVUS analysis of 31 true bifurcation lesions and 30 angiographically normal bifurcation segments including the main and side branches as well as parent vessel.

Results: The external elastic membrane (EEM) area changed significantly according to distance from bifurcation in the parent vessel and main branches of the lesion group while there was no significant change in the EEM area in the normal group.

The clinical features of transient left ventricular nonapical ballooning syndrome: comparison with apical ballooning syndrome.

Background: Recently, several cases of atypical left ventricular (LV) ballooning syndrome without involvement of the LV apex have been reported. However, there has been no assessment of the clinical features of this novel presentation or comparison with the typical transient LV apical ballooning syndrome.

Methods: We evaluated 47 patients diagnosed with transient LV ballooning syndrome.

[Effects of TES program on exercise capacity, self-efficacy and patient compliance in patients with myocardial infarction].

Purpose: This study aimed to develop a TES program to improve exercise capacity to promote patient compliance to the prescribed exercise, and to test the feasibility of the program.

Method: The 8-week TES program consisted of three components : exercise training, self-efficacy enhancement and social support. Using the matching of gender, age, and the left ventricular ejection fraction, thirty one subjects were consecutively assigned to either TES group (n=15, 52+7 years) or Control group (n=16, 58+11 years) 3 weeks after MI.