Standard Echo Research Articles

3D distortion-free, reduced FOV diffusion-prepared gradient echo at 3 T.

To develop a 3D distortion-free reduced-FOV diffusion-prepared gradient-echo sequence and demonstrate its application in vivo for diffusion imaging of the spinal cord in healthy volunteers. A 3D multi-shot reduced-FOV diffusion-prepared gradient-echo acquisition is achieved using a slice-selective tip-down pulse in the phase-encoding direction in the diffusion preparation, combined with magnitude stabilizers, centric k-space encoding, and 2D phase navigators to correct for intershot phase errors. The accuracy of the ADC values obtained using the proposed approach was evaluated in a diffusion phantom and compared to the tabulated reference ADC values and to the ADC values obtained using a standard spin echo diffusion-weighted single-shot EPI sequence (DW-SS-EPI). Five healthy volunteers were scanned at 3 T using the proposed sequence, DW-SS-EPI, and a clinical diffusion-weighted multi-shot readout-segmented EPI sequence (RESOLVE) for cervical spinal cord imaging. Image quality, perceived SNR, and image distortion were assessed by two expert radiologists. ADC maps were calculated, and ADC values obtained with the proposed sequence were compared to those obtained using DW-SS-EPI and RESOLVE. Consistent ADC estimates were measured in the diffusion phantom with the proposed sequence and the conventional DW-SS-EPI sequence, and the ADC values were in close agreement with the reference values provided by the manufacturer of the phantom. In vivo, the proposed sequence demonstrated improved image quality, improved perceived SNR, and reduced perceived distortion compared to DW-SS-EPI, whereas all measures were comparable against RESOLVE. There were no significant differences in ADC values estimated in vivo for each of the sequences. 3D distortion-free diffusion-prepared imaging can be achieved using the proposed sequence.

T1 and T2 measurements across multiple 0.55T MRI systems using open-source vendor-neutral sequences.

To compare T1 and T2 measurements across commercial and prototype 0.55T MRI systems in both phantom and healthy participants using the same vendor-neutral pulse sequences, reconstruction, and analysis methods. Standard spin echo measurements and abbreviated protocol measurements of T1, B1, and T2 were made on two prototype 0.55 T systems and two commercial 0.55T systems using an ISMRM/NIST system phantom. Additionally, five healthy participants were imaged at each system using the abbreviated protocol for T1, B1, and T2 measurement. The phantom measurements were compared to NMR-based reference measurements to determine accuracy, and both phantom and in vivo measurements were compared to assess reproducibility and differences between the prototype and commercial systems. Vendor-neutral sequences were implemented across all four systems, and the code for pulse sequences and reconstruction is freely available. For participants, there was no difference in the mean T1 and T2 relaxation times between the prototype and commercial systems. In the phantom, there were no significant differences between the prototype and commercial systems for T1 and T2 measurements using the abbreviated protocol. Quantitative T1 and T2 measurements at 0.55T in phantom and healthy participants are not statistically different across the prototype and commercial systems.

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography.

Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE. We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group). One hundred patients were included (mean age: 67±10). Compared with SAM- patients (n=60), SAM+ patients (n=40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p<.01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126±12° vs. 139±11° in the SAM- group; p<.01) and a higher posterior mitral leaflet length (1.4±.27cm vs. 1.25±.29, respectively; p<.01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p<.05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p<.01) was an independent predictor of SAM. SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

Sequence comparison of spoiled gradient echo and balanced steady-state free precession for pulmonary free-breathing proton MRI in patients and healthy volunteers: Correspondence, repeatability, and validation with dynamic contrast-enhanced MRI.

Phase-resolved functional lung (PREFUL) MRI is a proton-based, contrast agent-free technique derived from the Fourier decomposition approach to measure regional ventilation and perfusion dynamics during free-breathing. Besides the necessity of extensive PREFUL postprocessing, the utilized MRI sequence must fulfill specific requirements. This study investigates the impact of sequence selection on PREFUL-MRI-derived functional parameters by comparing the standard spoiled gradient echo (SPGRE) sequence with a lung-optimized balanced steady-state free precession (bSSFP) sequence, thereby facilitating PREFULs clinical application in pulmonary disease assessment. This study comprised a prospective dataset of healthy volunteers and a retrospective dataset of patients with suspected chronic thromboembolic pulmonary hypertension. Both cohorts underwent PREFUL-MRI with both sequences to assess the correspondence of PREFUL ventilation and perfusion parameters (A). Additionally, healthy subjects were scanned a second time to evaluate repeatability (B), whereas patients received dynamic contrast-enhanced (DCE)-MRI, considered the perfusion gold standard for comparison with PREFUL-MRI (C). Signal-to-noise ratio (SNR), calculated from the unprocessed images, was compared alongside median differences of PREFUL-MRI-derived parameters using a paired Wilcoxon signed rank test. Further evaluations included calculation of the Pearson correlation, intraclass-correlation coefficient for repeatability assessment, and spatial overlap (SO) for regional comparison of PREFUL-MRI and DCE-MRI. bSSFP showed a clear SNR advantage over SPGRE (median: 23 vs. 9, p< 0.001). (A) Despite significant differences, parameter values were strongly correlated (r≥0.75). After thresholding, binary maps showed high healthy overlap across both cohorts (SOHealthy > 86%) and high defect overlap in the patient cohort (SODefect≥48%). (B) bSSFP demonstrated slightly higher repeatability across most parameters. (C) Both sequences demonstrated comparable correspondence to DCE-MRI, with SPGRE excelling in absolute quantification and bSSFP in spatial agreement. Although bSSFP showed superior SNR results, both sequences displayed spatial defect concordance and highly correlated PREFUL parameters with deviations regarding repeatability and alignment with DCE-MRI.

Self-supervised multi-echo point cloud denoising in snowfall

Snowfall can cause noise to light detection and ranging (LiDAR) data. This is a problem since it is used in many outdoor applications, e.g., autonomous driving. We propose the task of multi-echo denoising, where the goal is to pick the echo that represents the objects of interest and discard other echoes. Thus, the idea is to pick points from alternative echoes unavailable in standard strongest echo point clouds. Intuitively, we are trying to see through the snowfall. We propose a novel self-supervised deep learning method and the characteristics similarity regularization to achieve this goal. The characteristics similarity regularization utilizes noise characteristics to increase performance. The experiments with a real-world multi-echo snowfall dataset prove the efficacy of multi-echo denoising and superior performance to the baseline. Moreover, based on extensive experiments on a semi-synthetic dataset, our method achieves superior performance compared to the state-of-the-art in self-supervised snowfall denoising. Our work enables more reliable point cloud acquisition in snowfall. The code is available at https://github.com/alvariseppanen/SMEDen.

Brain and Ventricle Volume Alterations in Idiopathic Normal Pressure Hydrocephalus Determined by Artificial Intelligence-Based MRI Volumetry.

The aim of this study was to employ artificial intelligence (AI)-based magnetic resonance imaging (MRI) brain volumetry to potentially distinguish between idiopathic normal pressure hydrocephalus (iNPH), Alzheimer's disease (AD), and age- and sex-matched healthy controls (CG) by evaluating cortical, subcortical, and ventricular volumes. Additionally, correlations between the measured brain and ventricle volumes and two established semi-quantitative radiologic markers for iNPH were examined. An IRB-approved retrospective analysis was conducted on 123 age- and sex-matched subjects (41 iNPH, 41 AD, and 41 controls), with all of the iNPH patients undergoing routine clinical brain MRI prior to ventriculoperitoneal shunt implantation. Automated AI-based determination of different cortical and subcortical brain and ventricular volumes in mL, as well as calculation of population-based normalized percentiles according to an embedded database, was performed; the CE-certified software mdbrain v4.4.1 or above was used with a standardized T1-weighted 3D magnetization-prepared rapid gradient echo (MPRAGE) sequence. Measured brain volumes and percentiles were analyzed for between-group differences and correlated with semi-quantitative measurements of the Evans' index and corpus callosal angle: iNPH patients exhibited ventricular enlargement and changes in gray and white matter compared to AD patients and controls, with the most significant differences observed in total ventricular volume (+67%) and the lateral (+68%), third (+38%), and fourth (+31%) ventricles compared to controls. Global ventriculomegaly and marked white matter reduction with concomitant preservation of gray matter compared to AD and CG were characteristic of iNPH, whereas global and frontoparietally accentuated gray matter reductions were characteristic of AD. Evans' index and corpus callosal angle differed significantly between the three groups and moderately correlated with the lateral ventricular volumes in iNPH patients [Evans' index (r > 0.83, p ≤ 0.001), corpus callosal angle (r < -0.74, p ≤ 0.001)]. AI-based MRI volumetry in iNPH patients revealed global ventricular enlargement and focal brain atrophy, which, in contrast to healthy controls and AD patients, primarily involved the supratentorial white matter and was marked temporomesially and in the midbrain, while largely preserving gray matter. Integrating AI volumetry in conjunction with traditional radiologic measures could enhance iNPH identification and differentiation, potentially improving patient management and therapy response assessment.

Motion robust coronary MR angiography using zigzag centric ky-kz trajectory and high-resolution deep learning reconstruction.

To develop a new MR coronary angiography (MRCA) technique by employing a zigzag fan-shaped centric ky-kz k-space trajectory combined with high-resolutiondeep learning reconstruction (HR-DLR). All imaging data were acquired from 12 healthy subjects and 2 patients using two clinical 3-T MR imagers, with institutional review board approval. Ten healthy subjects underwent both standard 3D fast gradient echo (sFGE) and centric ky-kz k-space trajectory FGE (cFGE) acquisitions to compare the scan time and image quality. Quantitative measures were also performed for signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) as well as sharpness of the vessel. Furthermore, the feasibility of the proposed cFGE sequence was assessed in two patients. For assessing the feasibility of the centric ky-kz trajectory, the navigator-echo window of a 30-mm threshold was applied in cFGE, whereas sFGE was applied using a standard 5-mm threshold. Image quality of MRCA using cFGE with HR-DLR and sFGE without HR-DLR was scored in a 5-point scale (non-diagnostic = 1, fair = 2, moderate = 3, good = 4, and excellent = 5). Image evaluation of cFGE, applying HR-DLR, was compared with sFGE without HR-DLR. Friedman test, Wilcoxon signed-rank test, or paired t tests were performed for the comparison of related variables. The actual MRCA scan time of cFGE with a 30-mm threshold was acquired in less than 5min, achieving nearly 100% efficiency, showcasing its expeditious and robustness. In contrast, sFGE was acquired with a 5-mm threshold and had an average scan time of approximately 15min. Overall image quality for MRCA was scored 3.3 for sFGE and 2.7 for cFGE without HR-DLR but increased to 3.6 for cFGE with HR-DLR and (p < 0.05). The clinical result of patients obtained within 5min showed good quality images in both patients, even with a stent, without artifacts. Quantitative measures of SNR, CNR, and sharpness of vessel presented higher in cFGE with HR-DLR. Our findings demonstrate a robust, time-efficient solution for high-quality MRCA, enhancing patient comfort and increasing clinical throughput.

Point-of-care AI-enhanced novice echocardiography for screening heart failure (PANES-HF)

The increasing prevalence of heart failure (HF) in ageing populations drives demand for echocardiography (echo). There is a worldwide shortage of trained sonographers and long waiting times for expert echo. We hypothesised that artificial intelligence (AI)-enhanced point-of-care echo can enable HF screening by novices. The primary endpoint was the accuracy of AI-enhanced novice pathway in detecting reduced LV ejection fraction (LVEF) < 50%. Symptomatic patients with suspected HF (N = 100, mean age 61 ± 15 years, 56% men) were prospectively recruited. Novices with no prior echo experience underwent 2-weeks’ training to acquire echo images with AI guidance using the EchoNous Kosmos handheld echo, with AI-automated reporting by Us2.ai (AI-enhanced novice pathway). All patients also had standard echo by trained sonographers interpreted by cardiologists (reference standard). LVEF < 50% by reference standard was present in 27 patients. AI-enhanced novice pathway yielded interpretable results in 96 patients and took a mean of 12 min 51 s per study. The area under the curve (AUC) of the AI novice pathway was 0.880 (95% CI 0.802, 0.958). The sensitivity, specificity, positive predictive and negative predictive values of the AI-enhanced novice pathway in detecting LVEF < 50% were 84.6%, 91.4%, 78.5% and 94.1% respectively. The median absolute deviation of the AI-novice pathway LVEF from the reference standard LVEF was 6.03%. AI-enhanced novice pathway holds potential to task shift echo beyond tertiary centres and improve the HF diagnostic workflow.

High-resolution anatomical imaging of the fetal brain with a reduced field of view using outer volume suppression.

To achieve high-resolution fetal brain anatomical imaging without introducing image artifacts by reducing the FOV, and to demonstrate improved image quality compared to conventional full-FOV fetal brain imaging. Reduced FOV was achieved by applying outer volume suppression (OVS) pulses immediately prior to standard single-shot fast spin echo (SSFSE) imaging. In the OVS preparation, a saturation RF pulse followed by a gradient spoiler was repeated three times with optimized flip-angle weightings and a variable spoiler scheme to enhance signal suppression. Simulations and phantom and in-vivo experiments were performed to evaluate OVS performance. In-vivo high-resolution SSFSE images acquired using the proposed approach were compared with conventional and high-resolution SSFSE images with a full FOV, using image quality scores assessed by neuroradiologists and calculated image metrics. Excellent signal suppression in the saturation bands was confirmed in phantom and in-vivo experiments. High-resolution SSFSE images with a reduced FOV acquired using OVS demonstrated the improved depiction of brain structures without significant motion and blurring artifacts. The proposed method showed the highest image quality scores in the criteria of sharpness, contrast, and artifact and was selected as the best method based on overall image quality. The calculated image sharpness and tissue contrast ratio were also the highest with the proposed method. High-resolution fetal brain anatomical images acquired using a reduced FOV with OVS demonstrated improved image quality both qualitatively and quantitatively, suggesting the potential for enhanced diagnostic accuracy in detecting fetal brain abnormalities in utero.

SIMPLIFID LUNG ULTRASOUND IN DIAGNOSIS OF HEART FAILURE WITH PRESERVED EJECTION FRACTION IN ARTERIAL HYPERTENSION

Objective: About 30% of patients with heart failure (HF) have normal Ejection Fraction (HFpEF). Pulmonary congestion is useful marker of HFpEF. The aim of this study was to determine the efficacy of ultrasound in patients with DHF. Design and method: We studied 250 patients with Arterial Hypertension and III-IV NYHA class HF from which 70 patients had HFpEF (group 1) and 100 patients Left Ventricular Diastolic Dysfunction but without signs of HF (control, group 2). All participants undergone standard Echo Cardiography. Sonographic evaluation of a lung was done in horizontal or vertical positions of patient, from 10 points of thoracic wall (5 points from each side), which corresponded to the projection of lower, middle and upper lobes of a right lung and upper and lower lobes of left lung. Results: In patients with HFpEF we significantly often found multiple (3 or more) B-lines or Comet tail Phenomenon (CTPh), which was registered in 91.1%. In 40.0% of control group patients, we also registered B-lines, but the count of them was less than 3 lines per each registration point (the difference between control an HF groups was significant). The count of points from where the CTPh was registered was 6.8 in HFpEF gr. and 0.7 in control. The B-lines were registered from 3 or more points of thoracic wall in 82.86% of patients of I gr and only 5% in II gr participants. In HF groups CTPh was prominent and multiple while in the control group it was single and short lasting, like lightening. There was good correlation between the count of B-line registration points from the thoracic wall and the heart failure NYHA class (r=0.56), left ventricular systolic (r=0.40) and diastolic (r=0.32) diameters and negative MAPS and TAPS (r=-0.42 and 0.41 respectively). Conclusions: Thoracic US is a sensitive and accurate method for evaluation pulmonary congestion in patients with AH and HFpEF. The US sign of pulmonary congestion in HF are B-lines or Comet tail phenomenon, which is protracted, prominent, multiple and registered from larger area of thoracic wall (3 points or more).

In vivo T2 measurements of the fetal brain using single-shot fast spin echo sequences.

We propose a quantitative framework for motion-corrected T2 fetal brain measurements in vivo and validate the single-shot fast spin echo (SS-FSE) sequence to perform these measurements. Stacks of two-dimensional SS-FSE slices are acquired with different echo times (TE) and motion-corrected with slice-to-volume reconstruction (SVR). The quantitative T2 maps are obtained by a fit to a dictionary of simulated signals. The sequence is selected using simulated experiments on a numerical phantom and validated on a physical phantom scanned on a 1.5T system. In vivo quantitative T2 maps are obtained for five fetuses with gestational ages (GA) 21-35 weeks on the same 1.5T system. The simulated experiments suggested that a TE of 400 ms combined with the clinically utilized TEs of 80 and 180 ms were most suitable for T2 measurements in the fetal brain. The validation on the physical phantom confirmed that the SS-FSE T2 measurements match the gold standard multi-echo spin echo measurements. We measured average T2s of around 200 and 280 ms in the fetal brain grey and white matter, respectively. This was slightly higher than fetal T2* and the neonatal T2 obtained from previous studies. The motion-corrected SS-FSE acquisitions with varying TEs offer a promising practical framework for quantitative T2 measurements of the moving fetus.

Quantifying cerebral microbleeds using quantitative susceptibility mapping from magnetization-prepared rapid gradient-echo.

T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) is commonly included in brain studies for structural imaging using magnitude images; however, its phase images can provide an opportunity to assess microbleed burden using quantitative susceptibility mapping (QSM). This potential application for MPRAGE-based QSM was evaluated using in vivo and simulated measurements. Possible factors affecting image quality were also explored. Detection sensitivity was evaluated against standard multiecho gradient echo (MEGE) QSM using 3-T in vivo data of 15 subjects with a combined total of 108 confirmed microbleeds. The two methods were compared based on the microbleed size and susceptibility measurements. In addition, simulations explored the detection sensitivity of MPRAGE-QSM at different representative magnetic field strengths and echo times using microbleeds of different size, susceptibility, and location. Results showed that in vivo microbleeds appeared to be smaller (× 0.54) and of higher mean susceptibility (× 1.9) on MPRAGE-QSM than on MEGE-QSM, but total susceptibility estimates were in closer agreement (slope: 0.97, r2: 0.94), and detection sensitivity was comparable. In simulations, QSM at 1.5 T had a low contrast-to-noise ratio that obscured the detection of many microbleeds. Signal-to-noise ratio (SNR) levels at 3 T and above resulted in better contrast and increased detection. The detection rates for microbleeds of minimum one-voxel diameter and 0.4-ppm susceptibility were 0.55, 0.80, and 0.88 at SNR levels of 1.5, 3, and 7 T, respectively. Size and total susceptibility estimates were more consistent than mean susceptibility estimates, which showed size-dependent underestimation. MPRAGE-QSM provides an opportunity to detect and quantify the size and susceptibility of microbleeds of at least one-voxel diameter at B0of 3 T or higher with no additional time cost, when standard T2*-weighted images are not available or have inadequate spatial resolution. The total susceptibility measure is more robust against sequence variations and might allow combining data from different protocols.

Agreement between Handheld and Standard Echocardiography for Diagnosis of Latent Rheumatic Heart Disease in Brazilian Schoolchildren from High-Prevalence Settings (Agreement between Screening and Standard Echo for RHD).

Introduction: Handheld echocardiography (echo) is the tool of choice for rheumatic heart disease (RHD) screening. We aimed to assess the agreement between screening and standard echo for latent RHD diagnosis in schoolchildren from an endemic setting. Methods: Over 14 months, 3 nonphysicians used handheld machines and the 2012 WHF Criteria to determine RHD prevalence in consented schoolchildren from Brazilian low-income public schools. Studies were interpreted by telemedicine by 3 experts (Brazil, US). RHD-positive children (borderline/definite) and those with congenital heart disease (CHD) were referred for standard echo, acquired and interpreted by a cardiologist. Agreement between screening and standard echo, by WHF subgroups, was assessed. Results: 1390 students were screened in 6 schools, with 110 (7.9%, 95% CI 6.5-9.5) being screen positive (14 ± 2 years, 72% women). Among 16 cases initially diagnosed as definite RHD, 11 (69%) were confirmed, 4 (25%) reclassified to borderline, and 1 to normal. Among 79 cases flagged as borderline RHD, 19 (24%) were confirmed, 50 (63%) reclassified to normal, 8 (10%) reclassified as definite RHD, and 2 had mild CHD. Considering the 4 diagnostic categories, kappa was 0.18. In patients with borderline RHD reclassified to non-RHD, the most frequent WHF criterion was B (isolated mitral regurgitation, 64%), followed by A (2 mitral valve morphological features, 31%). In 1 patient with definite RHD reclassified to normal, the WHF criterion was D (borderline RHD in aortic and mitral valves). After standard echo, RHD prevalence was 3.2% (95% CI 2.3-4.2). Conclusions: Although practical, RHD screening with handheld devices tends to overestimate prevalence.

Abstract 14701: Agreement Between Handheld and Standard Echocardiography for Diagnosis of Latent Rheumatic Heart Disease in Brazilian Schoolchildren From High-Prevalence Settings

Background: Handheld echocardiography (echo) is the tool of choice for Rheumatic Heart Disease (RHD) screening, based on the 2012 World Heart Federation (WHF) Criteria. We aimed to assess the agreement between screening and standard echo for diagnosis of latent RHD in schoolchildren from an endemic setting. Methods: Over 14 months, 3 non-physicians used handheld machines (GE, VSCAN) and the 2012 WHF Criteria to determine RHD prevalence in low-income public schools in Minas Gerais, Southeast Brazil. Consented children were eligible for participation. Studies were interpreted remotely using a telemedicine cloud-server by 2 experts in Brazil and the US. RHD-positive children (borderline and definite) and those with congenital heart disease (CHD) were referred for standard echo with portable devices (GE, Vivid IQ), with acquisition and interpretation by an expert cardiologist. Agreement between screening and standard echo, by category and according to the WHD criteria, was assessed, and the kappa statistic was applied. Results: A total of 1,390 students were screened in 6 schools and, among these, 110 (7.9%, 95% CI 6.5 - 9.5) were screen-positive and referred for standard echo, with mean age of 14±2 years, 80 (72%) women. Among the 16 cases initially diagnosed as definite RHD, 11 (69%) were confirmed, 4 (25%) reclassified to borderline and 1 to normal. Among the 79 cases flagged as borderline RHD, 19 (24%) were confirmed, 50 (63%) reclassified to normal, 8 (10%) to definite RHD and 2 had mild CHD. Among 11 children with CHD in screening, 4 were confirmed, 5 were reclassified to normal and 2 to RHD. Considering the 4 diagnostic categories, kappa was 0.18. In patients with borderline RHD reclassified to non-RHD, the most frequent WHF criteria was B (isolated mitral regurgitation): 64%, followed by A (2 morphological features of the mitral valve): 31%. In the only patient with definite RHD reclassified to normal, WHF criteria was D (borderline RHD in aortic and mitral valves). After standard echo, RHD prevalence was 3.2% (95% CI 2.3 - 4.2). Conclusions: Although practical, RHD screening with handheld devices tend to overestimate prevalence. Even in endemic settings, continuous education for detection, and application of risk stratification for management are crucial.

Abstract 14030: Hemodynamic Metrics Can Be Accurately Assessed by a Non-Invasive Sensor Patch: The Portable Technology for Wireless Cardiomyopathy Tracking (Patchwrk) Study

Background: Echocardiographic timing intervals provide valuable prognostic information in patients with pre-clinical cardiac dysfunction. Diastolic filling time (DFT) can identify left bundle branch block (LBBB) patients at higher risk for cardiomyopathy. The need for specialized equipment limits the utility of echo in longitudinal assessment. Hypothesis: A non-invasive multimodal sensor Sansa patch will enable accurate assessment of hemodynamic parameters such as DFT, ejection time (ET), and pre-ejection period (PEP). Methods: Fifty patients scheduled for clinically indicated echocardiography were prospectively enrolled and had simultaneous application of the Sansa patch at the time of echocardiography. Timing intervals were analyzed using continuous wave (CW), pulsed wave (PW), and tissue Doppler imaging (TDI). Data from the Sansa electrocardiogram (ECG), seismocardiogram (SCG), and phonocardiogram (PCG) were independently analyzed to identify valve openings/closures to estimate DFT, ET and PEP. Agreement between echo and Sansa estimates was assessed using the coefficient of determination (R 2 ) and compared with agreement between different echo views. Results: Forty-six of the 50 patients (92%) had data of sufficient quality for analysis. The mean ejection fraction was 53±8% and 11 patients (24%) had LBBB. By echo, the mean DFT, ET, and PEP were 408±137 milliseconds (ms), 297±35ms, and 107±32ms respectively. Sansa estimates for DFT, ET and PEP were 431±135ms, 286±43ms, and 89±34ms respectively. The R 2 for Sansa DFT compared to echo was 0.85. Comparing TDI and PW estimates of DFT within the same patients demonstrated an R 2 of 0.82. Conclusion: Non-invasive Sansa patch monitoring accurately identified key cardiac timing intervals within the error observed between standard echo views. These measures have prognostic value and monitoring them in the ambulatory setting may allow early cardiomyopathy detection and upstream intervention.

VirtMRI: A Tool for Teaching MRI

Magnetic resonance image formation is not trivial and remains a difficult subject for teaching. Therefore, we saw an urgent need to facilitate teaching by developing a practical and easily accessible MR image generator. Due to the increasing interest in X-nuclei MRI, sodium image generation is also offered. The tool is implemented as a web application that is compatible with all standard desktop browsers and is open source. The user interface focuses on the parameters needed for the creation and display of the resulting images. Available MR sequences range from the standard Spin Echo and Inversion Recovery over steady-state to conventional sodium and more advanced single and triple quantum sequences. Additionally, the user interface has parameters to alter the resolution, the noise, and the k-space sampling. Our software is free to use and specifically suited for teaching purposes.

Comparison of standard T2-weighted turbo spin echo and volumetric interpolated breath-hold examination magnetic resonance imaging sequences in the assessment of articular process dysplasia in Pug dogs with thoracolumbar myelopathy.

A retrospective study to compare the classification, as normal, hypoplastic or aplastic, of thoracic (T10-T13) caudal articular process (CAP) morphology in Pug dogs with a thoracolumbar myelopathy as normal, hypoplastic or aplastic, between T2 weighted Turbo Spin Echo (T2W-TSE), in sagittal and transverse planes, and Volumetric Interpolated Breath-hold Examination (VIBE) Magnetic Resonance Imaging (MRI) sequences, in comparison to Computed Tomography (CT). We hypothesized a stronger agreement for VIBE in comparison to T2W-TSE. Diagnostic accuracy of T2W-TSE was inferior to VIBE for aplastic (60%, 95% CI 0.561-0.639 vs. 78%, 95%CI 0.744-0.815) hypoplastic (44%, 95%CI 0.427-0.452 vs. 62.5%, 95%CI 0.595-0.655) and normal CAP (70%, 95%CI 0.655-0.744 vs. 87%, 95%CI 0.848-0.892). Superior accuracy of classification using VIBE vs. T2W-TSE sequences using the McNemar Chi squared test was significant for aplastic (p = 0.0002) and normal CAP (p = 0.004). VIBE sequences had a sensitivity of 96% and specificity of 75% to detect CAP abnormality and with T2W-TSE imaging sensitivity 81% and specificity of 75%. Three-dimensionally reconstructable VIBE sequences were significantly more accurate than traditional T2W-TSE MRI sequences in classifying CAP morphology, which should reduce the need for CT for pre-operative assessment.

Correlations between Achilles tendon material and structural properties and quantitative magnetic resonance imagining in different athletic populations

Achilles tendon stiffness (kAT) and Young’s modulus (yAT) are important determinants of tendon function. However, their evaluation requires sophisticated equipment and time-consuming procedures. The goal of this study was twofold: to compare kAT and yAT between populations using the classical approach proposed in the literature (a combination of ultrasound and force data) and the MRI technique to understand the MRI’s capability in determining differences in kAT and yAT. Furthermore, we investigated potential correlations between short and long T2* relaxation time, kAT and yAT to determine whether T2* relaxation time may be associated with material or structural properties. Twelve endurance and power athlete, and twelve healthy controls were recruited. AT T2* short and long components were measured using standard gradient echo MRI at rest, while kAT and yAT were evaluated using the classical method (combination of ultrasound and dynamometric measurements). Power athletes had the highest kAT (3064 ± 260, 2714 ± 260 and 2238 ± 189 N/mm for power athletes, endurance athletes and healthy control, respectively) and yAT (2.39 ± 0.28, 1.64 ± 0.22 and 1.97 ± 0.32 GPa for power athletes, endurance athletes and healthy control, respectively) and the lowest T2* short component (0.58 ± 0.07, 0.77 ± 0.06 and 0.74 ± 0.08 ms for power athletes, endurance athletes and healthy control, respectively). Endurance athletes had the highest T2* long component value. No correlations were reported between T2* long component, kAT or yAT in the investigated populations, whereas the T2* short component was negatively correlated with yAT. These results suggest that T2* short component could be used to investigate the differences in AT material properties in different populations.

The Role of Cardiopulmonary Exercise Testing in Hypertrophic Cardiomyopathy.

This review emphasizes the importance of cardiopulmonary exercise testing (CPET) in patients diagnosed with hypertrophic cardiomyopathy (HCM). In contrast to standard exercise testing and stress echoes, which are limited due to the ECG changes and wall motion abnormalities that characterize this condition, CPET allows for the assessment of the complex pathophysiology and severity of the disease, its mechanisms of functional limitation, and its risk stratification. It is useful tool to evaluate the risk for sudden cardiac death and select patients for cardiac resynchronization therapy (CRT), cardiac transplantation, or mechanical circulatory support, especially when symptomatology and functional status are uncertain. It may help in differentiating HCM from other forms of cardiac hypertrophy, such as athletes' heart. Finally, it is used to guide and monitor therapy as well as for exercise prescription. It may be considered every 2 years in clinically stable patients or every year in patients with worsening symptoms. Although performed only in specialized centers, CPET combined with echocardiography (i.e., CPET imaging) and invasive CPET are more informative and provide a better assessment of cardiac functional status, left ventricular outflow tract obstruction, and diastolic dysfunction during exercise in patients with HCM.

Impact of plasma volume redistribution on outcomes in patients with heart failure with reduced ejection fraction

Abstract Funding Acknowledgements Type of funding sources: None. Background The impact of capacitance and blood volume redistribution on outcomes of patients with chronic heart failure is incompletely understood. Quantitative plasma volume (PV) measurements together with echocardiographic evaluation allow a comprehensive assessment of the interplay between volumetric overload, cardiac chamber remodelling and myocardial function. Purpose We hypothesize that PV expansion is associated with myocardial and renal dysfunction, right ventricular-pulmonary arterial uncoupling and unfavorable outcomes in HF patients with reduced ejection fraction (HFrEF). Methods Patients hospitalized at Mayo Clinic with decompensated HF and who had PV by the indicator-dilution nuclear methodology (Daxor BVA100) were included. Patients were considered hypervolemic if BV was ≥25% over expected. The primary endpoint was the composite of all-cause mortality or heart transplantation. The closest TTE to the time of PV was used to measure various indexes of myocardial performance (standard echo parameters and global chamber-specific strain parameters). Event-free survival was estimated using the Kaplan-Meier method. The relationship between PV and various parameters was evaluated with correlation coefficient (r²). Results A total of 65 patients were enrolled in the study. Reduced LVEF was present in 53 (81.6%) patients. There were 44 events (32 deaths, 12 heart transplants) after a median follow-up of 43 months (IQR 14–65). Results in patients with HFrEF are presented in the Table. Our main findings were: 1) PV expansion was associated with an increased risk of adverse events (Figure 1); 2) Volume redistribution correlated with various indexes of cardiac chamber function, suggesting that volume overload and associated cardiac remodeling may be responsible for altered myocardial mechanics in patients with HFrEF (Figure 2); 3) right ventricular-pulmonary arterial uncoupling was triggered by the plasma volume expansion, that causes postcapillary pulmonary hypertension; 4) PV redistribution was also associated with renal dysfunction and increasing the level of the protein catabolism (Table 1). Conclusion Expansion of plasma volume in HFrEF patients is associated with left atrium dilatation, abnormal filling of both atria and right ventricular dilatation / dysfunction. Plasma volume redistributions apparently became a trigger of right ventricular-pulmonary arterial uncoupling and stimulated postcapillary pulmonary hypertension, renal dysfunction with increasing the level of protein catabolism and unfavorable outcomes.