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Background To systematically investigate the performance and interobserver variability of a new standardized workflow for the analysis of aortic hemodynamics based on 4D-flow MRI in a study with 30 subjects. The semi-automated workflow was developed to ensure faster and standardized data analysis including systematic placement of analysis planes, 3D-flow visualization, and quantification of standard clinical flow parameters.

Background Time-resolved three-dimensional phase contrast (4D flow) MRI allows for visualization of three-dimensional cardiovascular anatomy and pulsatile flow with full volumetric coverage in a single, easy to prescribe 3D acquisition. The technique provides comprehensive flow visualization and permits retrospective flow quantification at any user-defined region of interest. [1] To our knowledge, no center has incorporated 4D flow MRI as a part of standard clinical cardiovascular MRI (CMR). The goals of this study include: 1) reporting on the incorporation of 4D flow MRI acquisition and processing as part of clinical CMR workflow and 2) better understanding the clinical impact of 3D flow visualization and retrospective flow quantification derived from 4D flow MRI in CMR.

Background Transcatheter aortic valve replacement (TAVR) has emerged as an accepted therapeutic option for moderate and high-risk patients with severe aortic stenosis. In addition to vessel caliber, the presence and configuration of vascular calcifications by the iliofemoral access site is part of routine pre-interventional assessment with CTA and catheter angiography. Non-contrast MR angiography has been proven useful for evaluation of lower extremity peripheral vascular disease, however it cannot identify vascular calcifications using currently available sequences. Neutral contrast 3D and 3D point-wise encoding time reduction (PETRA) are novel MR techniques that can detect vascular calcifications and enable projection-like displays for review, similar to CT. We hypothesized that these techniques, associated with noncontrast Quiescent Interval Slice-Selective (QISS) MRA may be useful alternatives for pre-surgical planning in patients considered for TAVR.

Methods IRB approval was obtained. Twenty patients (age: 54.8 ± 14 years, M:F = 15:5) undergoing non-emergent CMR assessment for myocardial pathology were consecutively recruited. Nine healthy volunteers (age: 44.3 ± 14 years, M:F = 6:3) were also imaged. CMR was performed at 1.5T (MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany). The examination included acquisition of standard segmented SSFP (iPAT2) (GRAPPA accel factor 2, TR 40 msec, 2.1 × 2.1 × 10 mm) cine and two accelerated segmented SSFP acquisitions (TPAT accel factor 4, TR 37.7 msec, 2.1 × 2.1 × 6 mm), one with an investigational prototype inline iterative k-t-sparse SENSE reconstruction with L1 regularization along one spatial and temporal dimension (TPAT4i) (1)and the other with conventional SENSE reconstruction (TPAT4). Each technique was used to acquire a three(3Ch), four-chamber (4Ch), and short axis (SA) series in identical slice positions (Figure 1), with SA coverage of the entire left ventricle (LV) with 10 mm interslice gaps. Individual slice scan times were recorded. Quantitative LV functional analysis was performed. A reviewer blinded to acquisition type scored images for overall image quality, noise, and artifacts using a 5-point Likert scale. Continuous variables were compared between groups using a paired t-test, and ordinal variables were compared using a Wilcoxon signed-rank test.

Background Changes in myocardial strain parameters is of interest in patients with heart failure as an objective measure of disease severity. Speckle-tracking echocardiography (STecho) is the accepted standard of reference for myocardial strain analysis given superior temporal resolution; however, difficult acoustic windows and limited contrast to noise resolution can limit strain analysis. Preliminary work using deformation field analysis at steady state free precession (SSFP) cine MR imaging has shown that strain analysis at CMR is similar between conventional and highly accelerated GRAPPA cine acquisitions. The purpose of this study is to compare the strain values in patients with heart failure and preserved ejection fraction (HFpEF, left ventricular ejection fraction >50%) at SSFP cine MRI with ST-echo. Methods Retrospective analysis of Cardiac MR and echocardiographic images from 15 patients (5 men, avg age 61.2 yrs) with HFpEF. Cardiac MR images were obtained at 1.5 T (MAGNETOM Avanto, Siemens Medical Systems, Erlangen, AG) using GRAPPA factor 2 acceleration (temp res = 39.2 msec, spatial res = 1.5 × 1.5 mm, thickness = 6 mm). Myocardial strain analysis at Cardiac MR was performed using prototype software calculating Lagrangian strain from deformation field analysis (Siemens Corp, Corporate Technology, Princeton, NJ). Transthoracic echocardiography exams included apical 4-chamber and mid-ventricular short axis views. Left ventricular (LV) mid ventricular average and peak systolic radial and circumferential strains as well as longitudinal strain data was calculated. Peak and average right ventricular (RV) longitudinal strain was also obtained. CMR and ST-Echo derived strain indices were compared using the Pearson correlation. Inter and intraobserver variance was assessed for CMR-derived RV and LV longitudinal strain analysis using the intraclass correlation coefficient (ICC). Results

Background Bicuspid aortic valve (BAV) is the most common congenital heart defect whereby a significant percentage of patients experience dissection or progressive aortic dilation. There is increasing evidence that aortic hemodynamics such as wall shear stress (WSS) and flow jet eccentricity may exacerbate the development of aortopathy; however, these relationships have been investigated using experimental cardiac MRI protocols. We hypothesize that standard 2D through-plane encoded PC-MRI can aid in identifying BAV patients most at-risk for progressive aortic dilation.

Background Delayed enhancement (DE) CMR is the gold standard for detecting irreversibly damaged myocardial tissue (scar). Yet, direct impact of scar on regional systolic and diastolic left ventricular (LV) function is not well understood. Standard tools for LV velocities (Tissue Doppler Imaging) are limited by poor reproducibility and incomplete assessment of all regions and motion directions. Myocardial CMR velocity mapping (MVM) is reproducible, non-invasive, and allows direct measure of myocardial velocities of all LV motion components in all regions. Here, we analyze effects of LV scar burden on myocardial motion.

Background Cardiac MR (CMR) has emerged as the gold standard for the evaluation of biventricular systolic function. Semiautomated algorithms for investigating left ventricular systolic function exist, but application to the right ventricle (RV) is challenging. Recently, feature tracking has been developed to semi-automatically track the tricuspid annulus on 4-chamber cine imaging. The purpose of this feasibility study is to determine the ability of semiautomated quantification of the CMR tricuspid annular plane systolic excursion (CMR-TAPSE) to predict normal RV systolic function, comparing to echocardiography determined TAPSE (echo-TAPSE) and quantitative assessment of RV systolic function at CMR.

Background Three-dimensional, time-resolved phase contrast MRI (4D flow) was applied to characterize the aortic size and 3D hemodynamics continuously along the centerline of the thoracic aorta. The aim was to investigate the impact of age and gender on the variability of normal aortic size and velocities. Methods

Summary The purpose of this study is to evaluate semi quantitative perfusion parameter maps generated based on a fully automated non-rigid motion correction during a first pass myocardial perfusion (FPMP) MRI in patients with suspected coronary artery disease (CAD) or coronary micro vascular disease (CMVD). Background FPMP MRI is commonly used to assess CAD and most recently to assess cardiac involvement in asymptomatic patients with CMVD such as systemic sclerosis and diabetes mellitus. FPMP MRI evaluation relies on visual inspection for qualitative analysis but quantitative analysis of rest and stress perfusion data is desired to improve diagnosis. One main challenge of qualitative analysis includes cardiac and respiratory motion. To minimize this challenge, ap reviously described inline, fully automated motion correction method [Xue, H MICCAI 2009] generates a motion corrected dataset as well as pixel-wise upslope maps. Using the image at a time point selected for peak signal change during the first pass of contrast agent as the template, all other time points were registered into the template coordinate system. We compare qualitatively and quantitatively the original free breathing images and motion correted images with the corresponding maps pixel-wise upslope maps in patients with suspected CAD or CMVD. Methods

Background Non-invasive assessment of myocardial strain has many promising implications in the early detection and management of cardiac disease. Preliminary work at our institution has shown deformation field analysis of balanced steady state free precision (bSSFP) cine MR images to compare favorably with speckle-tracking echocardiography. We have also illustrated that global strain values obtained by this MR-based technique demonstrate good agreement across field strengths and temporal resolutions in healthy volunteers. To further delineate the potential of this technique, we assessed strain values across field strengths and temporal resolutions for myocardial regions (endo-, meso-, and epicardium), levels (base, mid, and apex), and smaller divisions (segments) within each region and level.

Background Left ventricular noncompaction (LVNC) is a diagnosis often made at imaging with uncertain prognostic value. Jenni echocardiogram and Petersen cardiac MR (CMR) criteria utilize a single long-axis view to quantify the maximal ratio of noncompacted to compacted myocardial thickness, but these have not been shown to correlate with clinical status or disease progression. Quantitation of the trabecular mass is now simple to perform using advanced post-processing tools. Prior studies demonstrated that elevated LV trabeculated mass helps differentiate patients with LVNC from healthy controls and patients with other non-ischemic cardiomyopathies, but distinguishing patients with morphologic LVNC (M-LVNC) from those with clinically significant LVNC (CS-LVNC) remains problematic. The purpose of this study was to evaluate the performance of trabecular mass quantification at CMR to differentiate patients with CS-LVNC and M-LVNC.

Background Cardiac MR is the reference standard for assessing biventricular systolic function and delayed enhancement. However, changes in systolic function as assessed by global parameters such as ventricular ejection fraction are late indicators of adverse structure-function changes. Myocardial strain has shown promise to identify abnormal potentially reversible regional myocardial function, preceding changes in the ejection fraction. Feature tracking cardiac MR is a novel technique to quantitate myocardial function, tracking biventricular myocardial features to generate Lagrangian strain values from existing cine balanced steady state free precession (bSSFP) data. The purpose of this study is to assess the feasibility of retrospective strain analysis in a patient cohort with biopsy-proven non-ischemic cardiomyopathy, comparing to strain data in healthy volunteers. Methods 26 consecutive patients (21 men, avg age 64 years) with a biopsy proven non-ischemic cardiomyopathy (NICM) and 20 healthy volunteers (14 men, avg age 44 years) underwent cardiac MR (CMR) imaging at 1.5T with bSSFP segmented cine imaging with a temporal resolution of 25-40 msec. bSSFP cine images were evaluated by a single observer using prototype software employing deformation field analysis to generate Lagrangian strain values for the left (LV - radial, circumferential, longitudinal) and right ventricles (RV - longitudinal). LV (LVEF) and RV ejection fraction (RVEF) were quantified on a dedicated workstation by a single observer. A twotailed student’s t-test assessed differences in strain values between groups, with an alpha of 0.05 chosen to demarcate statistical significance. Results

Background In the early stages of some cardiovascular diseases (CVDs), myocardial ischemia only occurs in a limited area. Thus, accurate detection of regional myocardial perfusion abnormalities is important for diagnosis. Recently, myocardial perfusion using MRI has become a promising non-invasive method to evaluate myocardial ischemia in CVDs. However, the reproducibility of MRI for assessment of regional perfusion has not been studied. This knowledge gap could affect the use of Cardiac MR in clinical practice. To address this clinical need, we evaluate the reproducibility of MRI perfusion in 12 healthy volunteers.

Background Diastolic dysfunction is often used as a marker for allograft rejection and may even precede systolic abnormalities. However, diastolic indices provided by echocardiography can be of inconsistent quality with low sensitivities. Cardiac magnetic resonance (CMR) with high temporal resolution cine imaging offers an alternate noninvasive method for evaluating ventricular function. The purpose of this study is to describe CMR LV diastology indices in a cohort of heart transplant patients, comparing CMR results to echocardiography. Methods

Background Bicuspid aortic valve (BAV) is known as the most common congenital anomaly and its complications (ascending aortic aneurysm, dissection) can lead to noticeable morbidity and mortality. There is increasing evidence that, in addition to its genetic background, changes in aortic hemodynamics may play an important role in the development of aortopathy in these patients. Studies have shown that BAV can substantially alter aortic hemodynamics, but it is unclear if the genetic basis can influence aortic properties and 3D blood flow in BAV relatives with normal tricuspid valves. In this study, we evaluated flow dynamics, aorta diameter and geometry in BAV relatives compared to normal volunteers using 4D flow MRI. Methods 15 controls and 3 families with one known BAV case in each family (Figure 1) underwent contrast agent enhanced (BAV relatives: MultiHance, controls: Ablavar) MRI (1.5 or 3T, Siemens, Germany) for the evaluation of ascending aorta (AAo) dimensions, aortic valve morphology, aortic shape, width to height ratio, and aortic 3D blood flow dynamics. To assess valve morphology and global cardiac function, breath-held, ECG-gated time-resolved (CINE) 2D balanced SSFP images were acquired. Aortic blood flow assessment was done using ECG and respiratory-gated CINE 3D phase-contrast MRI with 3D velocity encoding (4D flow) and full volumetric coverage (VENC = 150-250 cm/s, temporal resolution = 38.4-40.0 ms). Net flow and peak velocity were measured at the level of SOV (sinuses of valsalva), AAo (proximal to brachiocephalic trunk), distal aortic arch and descending aorta (DAo, level of left atrium) using commercial software (Ensight, CEI, NC). The presence and severity of helix and vortex flow was assessed by two readers using a defined 3-point grading scale in a blinded manner. Results Vortex and helix flow grading was performed with excellent inter-observer agreement (Cohen’ sk appa, = 0.73). Vortex flow was significantly more frequent in BAV relatives compared to controls (Figure 2, p < 0.001). Specifically, vortex flow was increased in the AAo (p < 0.004) and DAo (p < 0.025). Helix flow and flow parameters were similar in BAV relatives and controls. 47% of all BAV relatives had a different (p < 0.007) aortic shape than the typical round shape of the controls (93.3%). Peak velocity was reduced (p = 0.009) for gothic aortas and more vortices were found in cubic aortas (p < 0.001).

Objective The purpose of this study was to evaluate Time-resolved MR venography (TR-MRV) of the pulmonary venous circulation using the time-resolved angiography with interleaved stochastic trajectories (TWIST) method of time-resolved MRA (TR-MRA) and compare it with the more commonly used conventional Contrast enhanced magnetic resonance angiography (CE-MRA) approach in atrial fibrillation patients referred for pre-ablation pulmonary vein mapping. Background Catheter-based ablation of the pulmonary veins prevents recurrence of atrial fibrillation in 70-80% of patients during the first year of follow-up 1,2 . CE-MRA depicts the left atrium and pulmonary veins with high spatial resolution, enabling accurate measurement of pulmonary vein ostia to be made with depiction of their relationship to other structures. 1,3 Conventional CE-MRA however requires timing of contrast enhancement and produces images with overlap of venous and arterial structures, potentially obscuring pulmonary vein ostia. TR-MRA is an alternative to conventional CE-MRA and has been used successfully in other vascular territories. 4 Such an approach may be particularly advantageous in the pulmonary circulation with its rapid arteriovenous transit time, allowing acquisition of pure pulmonary venous phase images with a simpler imaging protocol. Material and methods 26 patients (15 males; age 60.0 ± 12.7y) referred for preablation pulmonary vein mapping underwent both conventional CE-MRA and TR-MRV with TWIST. Imaging was performed on a 1.5 Tesla (MAGNETOM Avanto, Siemens Healthcare) MRI scanner. Source partition and MIP images were evaluated. Quantitative Analysis: Pulmonary vein ostium orthogonal dimensions were measured using double oblique multiplanar reformatting. Qualitative Analysis: For qualitative analysis, both source partition images and MIP images were assessed by two observers. Pulmonary vein conspicuity was scored on a scale of 1-4 (1=poor, 2=fair, 3=good, 4=excellent). The number of pulmonary veins (3 veins= common ostium, 4 veins = normal, 5 veins=accessory vein) was recorded.

Background Cardiac MR (CMR) has emerged as the gold standard in assessing biventricular size and systolic function with segmented balanced steady-state free-precession (bSSFP) cine acquisitions. The application of a novel prototype iterative reconstruction technique to sparsely undersampled segmented bSSFP cine acquisitions may enable higher acceleration factors while shortening image acquisitions, thus maintaining adequate image quality for quantitative analysis. The purpose of this study is to evaluate the clinical utility of a segmented sparsely sampled 2D CINE imaging technique, with a prototype iterative SENSE reconstruction using L1-regularization, in the quantitative assessment of right ventricular (RV) systolic function.

Background Although contrast-enhanced first-pass MRA (FP-MRA) is frequently used to visualize the vasculature, it may not be suitable for the assessment of congenital heart disease. Blood-pool contrast agents remain within the intravascular space for several hours, allowing vessels to be imaged without relying on accurate contrast bolus timing. The purpose of this study is to compare steadystate magnetic resonance angiography (SS-MRA) following injection of a blood-pool contras agent to first-pass MR angiography (FP-MRA) in adults with congenital heart disease.