3D Cardiac Magnetic Resonance Research Articles

Cloud-processed 4D CMR flow imaging for pulmonary flow quantification

ObjectivesIn this study, we evaluated a cloud-based platform for cardiac magnetic resonance (CMR) four-dimensional (4D) flow imaging, with fully integrated correction for eddy currents, Maxwell phase effects, and gradient field non-linearity, to quantify forward flow, regurgitation, and peak systolic velocity over the pulmonary artery. MethodsWe prospectively recruited 52 adult patients during one-year period from July 2014. The 4D flow and planar (2D) phase-contrast (PC) were acquired during same scanning session, but 4D flow was scanned after injection of a gadolinium-based contrast agent. Eddy-currents were semi-automatically corrected using the web-based software. Flow over pulmonary valve was measured and the 4D flow values were compared against the 2D PC ones. ResultsThe mean forward flow was 92 (±30) ml/cycle measured with 4D flow and 86 (±29) ml/cycle measured with 2D PC, with a correlation of 0.82 and a mean difference of −6ml/cycle (−41–29). For the regurgitant fraction the correlation was 0.85 with a mean difference of −0.95% (−17–15). Mean peak systolic velocity measured with 4D flow was 92 (±49) cm/s and 108 (±56) cm/s with 2D PC, having a correlation of 0.93 and a mean difference of 16cm/s (−24–55). Conclusion4D flow imaging post-processed with an integrated cloud-based application accurately quantifies pulmonary flow. However, it may underestimate the peak systolic velocity.

Patient-specific coronary blood supply territories for quantitative perfusion analysis

Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis.

96-65: Types of Thebesian valve in Cardiac Magnetic Resonance

Visualization of the Thebesian valve - guard of the coronary sinus (CS) - can be possible in the cardiac magnetic resonance (CMR). Such pre-visualization can potentially be valuable before cannulation of the CS. Methods: 122 patients (aged 49.2 ± 17.2; 41W) were included. CMR was performed on all participants using a GE Optima MR450w 1.5T (GEM) with a 3D cardiac coil. A standard steady-state free precession and 4-channel long axis sequences were used for the basic evaluation of the Thebesian valve. Our original sequence or navigator gated 3D free breathing CMR were performed on selected patients. The classification of the Thebesian valve in CMR was based on anatomical characteristics. Results: Examples of the Thebesian valve in CMR are presented in the figure below. Average diameter of the CS ostium was 9.9 ± 9.3 mm. Thebesian valve was found in 56 patients (45.9%). Average diameter of the CS ostium in patients with a valve present was 11.9 ± 17.9 and without Thebesian valve was 8.9 ± 0.4; p = 0.429 NS. In 21 patients (37.5%) the valve almost totally covered the CS ostium (type D); this can potentially create problems during CS cannulation. In 20 (35.7%) cases, the valve was visible from the right atrium wall (types A1, A2) and in one case (1.8%), it was visible from the inter-atrial septum (type B1). In 12 (21.4%) cases, the valve had two parts with a gap between them (type C).

X-ray and magnetic resonance imaging fusion for cardiac resynchronization therapy

Cardiac Resynchronization Therapy (CRT) can effectively treat left ventricle (LV) driven Heart Failure (HF). However, 30% of the CRT recipients do not experience symptomatic benefit. Recent studies show that the CRT response rate can reach 95% when the LV pacing lead is placed at an optimal site at a region of maximal LV dyssynchrony and away from myocardial scars. Cardiac Magnetic Resonance (CMR) can identify the optimal site in three dimensions (3D). 3D CMR data can be registered to clinical standard x-ray fluoroscopy to achieve an optimal pacing of the LV. We have developed a 3D CMR to 2D x-ray image registration method for CRT procedures. We have employed the LV pacing lead on x-ray images and coronary sinus on MR data as landmarks. The registration method makes use of a guidewire simulation algorithm, edge based image registration technique and x-ray C-arm tracking to register the coronary sinus and pacing lead landmarks.

Development of integrated high-resolution three-dimensional MRI and computational modelling techniques to identify novel genetic and anthropometric determinants of cardiac form and function

BackgroundThe genetic and environmental factors that define cardiac structure and function, particularly at the intersection between health and the earliest stages of disease, remain poorly characterised. Conventional cardiovascular imaging provides limited, semi-quantitative, and global metrics of the heart, and these methods are insensitive to regional variation. We aimed to assess whether three-dimensional (3D) cardiac magnetic resonance (CMR) phenotyping could provide methodological, statistical, and scaling advantages for population studies. MethodsVolunteers without self-reported cardiovascular disease were recruited prospectively. A cardiac atlas-based software was developed to quantitatively analyse two-dimensional (2D) and 3D CMRs. Phenotypes (eg, wall thickness and function) were extracted at 46 000 points across the heart and genotyping and whole-exome sequencing performed. Associations between 3D phenotypes, clinical variables, and genotypes were studied with 3D regression models and Bayesian latent factor analysis. Findings1850 volunteers (mean age 41 years, SD 13) took part in the study. Automatically analysed 3D images were more accurate than 2D images at defining cardiac surfaces, enabling a reduction in the sample size required for epidemiological and genetic studies of the heart. Computational, high-dimensional 3D phenotyping revealed that systolic blood pressure, body composition, and genetic variation (both rare and common) were associated with regional rather than global changes in cardiac phenotypes, which were not detected by 2D CMR. 3D CMR revealed latent precursors of the hypertensive heart phenotype in healthy individuals that were previously unappreciated. In a 3D genome-wide association study we detected a larger number of loci significantly (p<5×10−10) associated with regional cardiac variation, showing genetic control of localised cardiac physiological features. InterpretationWe have shown that quantitative 3D CMR combined with computational modelling and advanced statistical analysis provide new insights into the genetic and anthropometric determinants of cardiac morphological and physiological features. Our approach provides new opportunities for understanding the structure and function of the human heart, and reveals hidden features only apparent through big data analytical methods. This approach can be applied at scale to very large datasets for mechanistic or interventional studies. FundingMedical Research Council, British Heart Foundation, Fondation Leducq grants.

Application of Virtual Three-Dimensional Models for Simultaneous Visualization of Intracardiac Anatomic Relationships in Double Outlet Right Ventricle.

Our goal was to construct three-dimensional (3D) virtual models to allow simultaneous visualization of the ventricles, ventricular septal defect (VSD) and great arteries in patients with complex intracardiac anatomy to aid in surgical planning. We also sought to correlate measurements from the source cardiac magnetic resonance (CMR) image dataset and the 3D model. Complicated ventriculo-arterial relationships in patients with complex conotruncal malformations make preoperative assessment of possible repair pathways difficult. Patients were chosen with double outlet right ventricle for the complexity of intracardiac anatomy and potential for better delineation of anatomic spatial relationships. Virtual 3D models were generated from CMR 3D datasets. Measurements were made on the source CMR as well as the 3D model for the following structures: aortic diameter in orthogonal planes, VSD diameter in orthogonal planes and long axis of right ventricle. A total of six patients were identified for inclusion. The path from the ventricles to each respective outflow tract and the location of the VSD with respect to each great vessel was visualized clearly in all patients. Measurements on the virtual model showed excellent correlation with the source CMR when all measurements were included by Pearson coefficient, r=0.99 as well as for each individual structure. Construction of virtual 3D models in patients with complex conotruncal defects from 3D CMR datasets allows for simultaneous visualization of anatomic relationships relevant for surgical repair. The availability of these models may allow for a more informed preoperative evaluation in these patients.

Turbulent kinetic energy in the ascending aorta is greater in bicuspid than tricuspid aortic valve stenosis

Background The main determinant of the haemodynamic significance of aortic stenosis (AS) is the irreversible pressure loss that is created by the stenosis. The majority of the pressure loss is caused by conversion/dissipation of turbulent kinetic energy (TKE) to heat. Recent developments in cardiac magnetic resonance 4D flow imaging have allowed the noninvasive assessment of TKE. Bicuspid aortic valve disease is known to be associated with a larger ascending aorta and disordered flow patterns, and we hypothesised that peak TKE would be higher in bicuspid AS than tricuspid AS. Methods 15 patients with bicuspid AS (mean age 63.6 years; mean aortic valve area 1.4cm 2 ; mean dimension of the ascending aorta at the level of the pulmonary artery 3.9cm) and no more than mild other valve disease were compared with 22 patients with tricuspid AS (mean age 72.9 years; mean aortic valve area 1.2cm 2 ; mean dimension of the ascending aorta at the level of the pulmonary artery 3.2cm) and no more than mild other valve disease. All subjects underwent time resolved, three dimensional cine magnetic resonance flow imaging at 3 Tesla, for the assessment of peak TKE. The peak TKE was obtained by integrating the TKE per voxel across the ascending aorta at each time frame of the cardiac cycle. Results

Abstract 19466: Preliminary Experience Using Multiplexed Imaging of the Sympathetic Autonomic Nervous System - Impact on Outcome of Catheter Ablation of Atrial Fibrillation

Introduction: Catheter ablation of ganglionated plexi (GP) as an add on to pulmonary vein (PV) isolation has been reported to significantly improve outcome of atrial fibrillation (AF) ablation. In order to facilitate localization of these GPs, a novel imaging study is proposed, assessing the uptake of iodine-123 metaiodobenzylguanidine (mIBG, an analog of norepinephrine)in combination with 3D surface reconstruction from contrast computed tomography (cCT) or cardiac magnetic resonance (CMR). Methods: A total of 8 patients (5 male, median age 58 yrs) underwent mIBG SPECT using a dedicated cardiac camera (D-SPECT, SUMO, Spectrum Dynamics). This data was merged with 3D CMR or cCT and finally imported into CARTO (Biosense Webster). Using the individual mediastinum uptake as a normalizing factor, high uptake sites in the epicardial fat pads around the left atrium (LA) were identified. Five patients had paroxysmal AF whilst 3 present in persistent (n=2) or longstanding persistent (n=1) AF. Only 3 patients were treated de-novo, with the remaining failing in median 2 previous ablation procedures. Invasively, high uptake sites were mapped using high frequency stimulation (HFS) to confirm GP locations, which were subsequently ablated. PV (re) isolation and CFAE ablation was performed as needed. Results: Both the mIBG and CT or CMR scans were performed without complications. Focal mIBG uptake sites corresponded to anatomical GP sites, but individual variations of additional GPs were observed. Using HFS stimulation, GP sites were confirmed, but exact localization was highly depending on accurate image registration. Median follow-up of 9.2 months with all PAF and persistent AF patients in SR (1 AT redo), while the long-standing AF relapsed. Conclusion: The combination of mIBG SPECT and 3D anatomical imaging (SUMO protocol) provides a novel type of “road map” for localizing GPs during AF ablation. GPs were variable in number and location and were invasively confirmed using high frequency stimulation. Addition of GP ablation to standard AF ablation strategies seems beneficial in patients with paroxysmal or persistent AF. Further studies in larger patient cohorts are needed to confirm these initial observations.

Comparison of Two- and Three-Dimensional Transthoracic Echocardiography to Cardiac Magnetic Resonance Imaging for Assessment of Paravalvular Regurgitation After Transcatheter Aortic Valve Implantation

This study evaluated 2-dimensional (2D) transthoracic echocardiography (TTE) using Valve Academic Research Consortium-2 (VARC-2) criteria and 3-dimensional (3D) TTE for assessment of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) in comparison with cardiac magnetic resonance (CMR) imaging. In 71 patients, 2D TTE, 3D TTE, and CMR imaging were performed to assess AR severity after TAVI. Using 2D TTE, AR severity was graded according to VARC-2 criteria and regurgitant volume (RVol) was determined. Three-dimensional color Doppler TTE allowed direct planimetry of the vena contracta area of the paravalvular regurgitation jet and calculation of the RVol as product with the velocity-time integral. RVol by CMR imaging was measured by phase-contrast velocity mapping in the ascending aorta. After TAVI, mean RVol determined by CMR imaging was 9.2 ± 9.6 ml/beat and mean regurgitant fraction was 13.3 ± 10.3%. AR was assessed as none or mild in 58 patients (82%) by CMR imaging. Correlation of 3D TTE and CMR imaging on RVol was better than correlation of 2D TTE and CMR imaging (r = 0.895 vs 0.558, p <0.001). There was good agreement between RVol by CMR imaging and by 3D TTE (mean bias = 2.4 ml/beat). Kappa on grading of AR severity was 0.357 between VARC-2 and CMR imaging versus 0.446 between 3D TTE and CMR imaging. Intraobserver variability for analysis of RVol of AR after TAVI was 73.5 ± 52.2% by 2D TTE, 16.7 ± 21.9% by 3D TTE, and 2.2 ± 2.0% by CMR imaging. In conclusion, 2D TTE considering VARC-2 criteria has limitations in the grading of AR severity after TAVI when CMR imaging is used for comparison. Three-dimensional TTE allows quantification of AR with greater accuracy than 2D TTE. Observer variability on RVol after TAVI is considerable using 2D TTE, significantly less using 3D TTE, and very low using CMR imaging.

Is MRI the Preferred Method for Evaluating Right Ventricular Size and Function in Patients With Congenital Heart Disease?

Is MRI the Preferred Method for Evaluating Right Ventricular Size and Function in Patients With Congenital Heart Disease?

An in vitro validation of cardiac magnetic resonance 4D flow measurements with bioprosthetic mitral valve flow volumes quantification

Background Four dimensional flow MRI is a new methodology for evaluating the morphology of the heart using phase contrast cardiac magnetic resonance imaging not only in the usual three dimensions (x, y and z), but also across time. The full breadth of this new form of imaging has yet to be fully established. In order to evaluate this modality and its accuracy, we decided to use 4D flow MRI to quantify diastolic flow volumes across a bioprosthetic valve (BPV) in a controlled and reproducible in vitro system. Methods Three different sizes of BMV’s (27, 29, and 31 mm) were consecutively mounted in an MRI compatible flow loop where the flow conditions could be controlled using software that programmed a pump to generate pulsatile, physiologic ventricular ejection and filling simulations. The generated pulses were generated using each valve and mimicked diastolic flow volumes of about 70, 90 and 110 ml/beat at a rate of 70 bpm. An in-series ultrasonic flow transducer (UFT) was used to measure flow (L/min) by which diastolic flow volumes were determined. The acquisition of 3D cine (4D flow) phase contrast velocity data was acquired in a 1.5 Tesla MRI scanner (Avanto, Siemens Medical Solutions, Inc., Erlangen, Germany). The typical imaging parameters were: repetition time 45-48 ms, echo time 2.75 ms, flip angle 15°, slice thickness 1.5 mm, field of view 350 × 260 mm2, voxel size 1.5 × 1 × 1.25 mm3. The flow measurements were determined at 3 locations within the valve in post-imaging examination including at the valve base, leaflet tips, and midway between the base and the tips. Results

Value of Two‐Dimensional Longitudinal Strains Analysis to Assess the Impact of Thrombus Aspiration during Primary Percutaneous Coronary Intervention on Left Ventricular Function: A Speckle Tracking Imaging Substudy of the EXPIRA Trial

Thrombectomy during primary percutaneous coronary intervention (Th-PCI) improves myocardial reperfusion in the absence of significant changes, in the acute phase, in traditional two-dimensional (2D) echo indexes of left ventricular (LV) function. The aim of this study was to evaluate the potential of 2D speckle tracking echocardiography (2DSTE) analysis in assessing the efficacy of thrombectomy as compared to standard 2D echo and cardiac magnetic resonance (CMR) data. Two-dimensional speckle tracking echocardiography analysis was performed in 60 anterior ST-segment elevation myocardial infarction (STEMI) patients to assess global (GLS), segmental (SLS) and regional longitudinal strain (RLS). 2D echo and CMR were performed within 5 days after PCI. Patients were divided into 2 groups according to the different methods of reperfusion used: 28 pts Th-PCI and 32 pts standard PCI (S-PCI). Baseline clinical and angiographic characteristics, 2D echo, and DE-CMR data before and after PCI were similar in the 2 groups, except for microvascular obstruction (MVO), significantly lower (P = 0.001) in Th-PCI group. Conversely, GLS was significantly higher in Th-PCI group (P < 0.001), and in particular in the subset of patients without MVO (P = 0.012). RLS was also significantly higher in Th-PCI group (P = 0.001). GLS significantly correlates with infarct size, (R = 0.47; P = 0.03) and MVO (R = 0.69, P = 0.001). Finally, SLS was significantly lower in the DE segments (P < 0.001). Patients treated with Th-PCI had a more preserved microvascular integrity resulting in a better myocardial longitudinal deformation. 2DSTE analysis adds significant information on the efficacy of thrombus aspiration as compared to standard echocardiography and it is closely related to the extent of microvascular damage.

Comparison of Two- and Three-Dimensional Unenhanced and Contrast-Enhanced Echocardiographies Versus Cineventriculography Versus Cardiac Magnetic Resonance for Determination of Left Ventricular Function

Contrast enhancement has been shown to improve detection of regional wall motion abnormalities (RWMA) in 2-dimensional (2D) echocardiography. This study determined the use of contrast enhancement in the setting of 3-dimensional (3D) echocardiography for definition of left ventricular RWMA compared with 2D echocardiography, cineventriculography, and cardiac magnetic resonance (CMR). In 63 patients, unenhanced and contrast-enhanced (SonoVue; Bracco Imaging S.p.A., Milan, Italy) 2D and 3D echocardiographies, CMR, and cineventriculography were performed. Hypokinesia in ≥1 segment defined the presence of RWMA. Interreader agreement (IRA) between 2 blinded off-site readers on presence of RWMA was determined within each imaging technique. Intermethod agreement among imaging techniques was analyzed. A standard of truth for the presence of RWMA was obtained by an independent expert panel decision. IRA on presence of RWMA expressed as Cohen's κ coefficient was 0.27 for unenhanced 3D echocardiography, 0.40 for unenhanced 2D echocardiography, 0.57 for CMR, and 0.51 for cineventriculography. The use of contrast increased IRA on RWMA to 0.42 for 3D echocardiography and to 0.56 for 2D echocardiography. Agreement with CMR on RWMA increased for 3D echocardiography when contrast enhancement was used (κ 0.40 vs 0.22 for unenhanced 3D echocardiography). Similarly, agreement of 2D echocardiography with CMR on RWMA increased with contrast enhancement (κ 0.50 vs 0.32). Accuracy to detect expert panel-defined RWMA was highest for CMR (84%) followed by 2D contrast echocardiography (78%) and 3D contrast echocardiography (76%). It was lesser for 2D and 3D unenhanced echocardiographies. In conclusion, analysis of RWMA is characterized by considerable interreader variability even using high-quality imaging techniques. IRA on RWMA is lower with 3D echocardiography compared with 2D echocardiography. IRA on RWMA and accuracy to detect panel-defined RWMA improve with contrast enhancement irrespective of the 2D or 3D echocardiography use.

259 ASYMMETRICAL SEPTAL HYPERTROPHY IS ASSOCIATED WITH MEAN ARTERIAL BLOOD PRESSURE IN HEALTHY ADULTS: DATA FROM HIGH RESOLUTION 3D CARDIAC MRI

Background Left ventricular hypertrophy (LVH) is the result of complex interactions between genes and environmental factors, and an independent risk factor for all-cause mortality. Clinically, it is important to differentiate ‘physiological’ LVH, such as in hypertension, from pathological LVH as found in hypertrophic cardiomyopathy. Standard methods of cardiac phenotyping such as echocardiography or 2D cardiac magnetic resonance (CMR) provide only macroscopic descriptors of LV mass (LVM) and function. These methods are underpowered for population wide study of regional wall thickness variability. Methods and Results 187 healthy multi-ethnic volunteers (105 female, age range 18–72, mean age 40) were recruited into a sub-study of the UK GenScan project. Exclusion criteria included established history of cardiovascular disease, hypertension, diabetes or hypercholesterolemia. Subjects were phenotyped by CMR using a 1.5T Philips Achieva system with a 32 element cardiac phased-array coil. High resolution 3D cine imaging of the LV was obtained with a voxel size of 2x2x4 mm and 20 cardiac phases. Three blood pressure (BP) measurements were taken and averaged (in mmHg): Mean systolic BP 123 (range 90–186), mean diastolic BP 80.4 (range 47–109). The high resolution 3D images were automatically segmented using training data from 10 healthy volunteers in which the myocardium had been manually labelled at end-diastole and end-systole (Figure 1). The 187 3D segmentations were exactly co-registered with each other so that corresponding points within the myocardium could be accurately compared within the cohort. Mean wall thickness was calculated at each point as the distance between the endocardial and epicardial surfaces. Automated measurements were validated against manual readings using standard clinical software (Philips Extended Workspace). LV end-diastolic volumes and LVM measurements were highly correlated (R 2 =.98 and R 2 =0.93 respectively). Mass univariate analysis was performed on the co-registered 3D models with wall thickness as the dependent variable. Pooling data from all the subjects, we plotted wall thickness at each 3D coordinate as a linear function of Mean Arterial Pressures (MAP) with gender and age held constant. The 3D models showed that blood pressure associated LVH begins asymmetrically within the mid-septum and progressively extends towards the base and apex with rising MAP (Figure 2). The lateral wall and apex are relatively spared. Conclusions Whole-heart high-resolution 3D CMR provides new opportunities for quantitative phenotyping of the heart and understanding the genetic and environmental determinants of heart disease. In this study we used these techniques to show the pattern of progressive asymmetrical septal hypertrophy that is associated with increasing blood pressure even within the general population.

Mitral regurgitation recovery and atrial reverse remodeling following pulmonary vein isolation procedure in patients with atrial fibrillation: a clinical observation proof-of-concept cardiac MRI study

Reverse remodeling of the left atrium (LA) following successful pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) has been well documented. However, mitral regurgitation (MR) recovery after successful PVI has never been demonstrated systematically. The objective of our study was to retrospectively analyze the effectiveness of PVI in patients with AF on recovery of MR using cardiac magnetic resonance (CMR) imaging. Prior to PVI, patients underwent a clinically indicated CMR imaging. Post-PVI (6 ± 2months), patients underwent a follow-up MRI and were classified into two groups-responders (R) and non-responders (NR) to PVI-as assessed by cessation of AF at the end of the prespecified 6-month (14-day "P" sensitive event monitor defined) follow-up period. Furthermore, CMR was used to evaluate the severity of MR (0 to 4+) and to relate changes in MR to LA volumes as well as mitral apparatus geometry. Patients who had mild and higher MR (2+) on baseline CMR and had a post-PVI CMR were selected for final analysis. Out of the consecutive 122 patients with AF who underwent PVI, 74 patients that had mitral regurgitation on initial CMR were included in the study. Of these74 patients with AF with MR, 52 (70%) were classified as R and 22 (30%) were classified as NR. Baseline demographics were similar between the groups. In the subgroup with mild to severe MR, pre vs. post in the R group MR severity significantly improved (mean = 2.3, median = 2.0 vs. mean = 1.0, median = 1.0, p < 0.0001) and was matched by favorable reverse remodeling of the mitral apparatus geometry (annulus = 35 ± 4 vs. 33 ± 3mm, p < 0.002; tenting area = 175 ± 56 vs.137 ± 37mm(2), p < 0.003; tenting height = 8 ± 2 vs.7 ± 2mm, p < 0.02; and tenting angle = 129 ± 10° vs. 131 ± 11°, p = 0.1). However, in the NR subgroup, MR failed to improve (mean = 2.2, median = 2.0 vs. mean = 1.5, median = 1.0, p = NS) and paralleled general failure of mitral geometry reverse remodeling (annulus = 35 ± 4 vs. 35 ± 4mm, p = 0.2; tenting area = 153 ± 39 vs. 152 ± 34mm(2), p = NS; tenting height = 7 ± 1 vs. 7.0 ± 2, p = 0.1; and tenting angle = 131 ± 11° vs. 133 ± 10°, p = NS). In those with lesser degrees of MR, favorable remodeling was predicated on responder status to PVI. Similarly, other cardiac dimensions pre- to post-PVI favorably improved in the R group, but not in the NR group. In those with durable maintenance of normal sinus rhythm (NSR), cardiac reverse remodeling demonstrated by 3D CMR occurs and is matched by marked improvements in MR and mitral apparatus, likely contributing to continued maintenance of NSR.

The UK GenScan study - population-based imaging genetics research using 3D Cardiac Magnetic Resonance

Background Cardiac structure and function results from complex interactions between genes, molecular regulators and environmental factors. Until recently, imaging-genetics studies had limited power as standard methods of cardiac phenotyping rely on global indices of mass and function, providing only macroscopic descriptors. Manual analysis of large cohorts is time consuming and subject to interobserver variability. Current cardiac magnetic resonance (CMR) cine imaging techniques are limited by poor through-plane resolution. Here we present a high resolution 3D left ventricular atlas with automated segmentation.

Multicenter evaluation of dynamic three-dimensional whole-heart myocardial perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve

Background Cardiac magnetic resonance (CMR) perfusion imaging yields high diagnostic accuracy for the detection of coronary artery disease (CAD) [1]. However, standard 2D multislice CMR perfusion techniques only provide limited coverage and hence prohibit computation of myocardial ischemic burden. Recently, two single-center 3D CMR perfusion studies have proven highly diagnostic for the detection of CAD relative to quantitative coronary angiography (QCA) [2] and fractional flow reserve (FFR) [3]. The aim of our prospective multicenter study is to assess the diagnostic performance of 3D CMR perfusion imaging in comparison with FFR.

Potency of integrating three-dimensional cardiac magnetic resonance imaging into electroanatomic mapping to perform catheter ablation in pediatrics

Background Radio-frequency catheter ablation (RFCA) in children is difficult because the size of heart chamber change with age and the catheter made for adults is not appropriate for a child. Three-dimensional (3D) images for electroanatomic mapping (EAM) have been used to create from images of multi-detector computed tomography (MDCT) which need to perform entailed by contrast medium injection and radiation exposure. This study sought to evaluate the usability of 3D Cardiac Magnetic Resonance Image (CMR) in pediatrics cases.

Screening Adult Survivors of Childhood Cancer for Cardiomyopathy: Comparison of Echocardiography and Cardiac Magnetic Resonance Imaging

To compare two-dimensional (2D) echocardiography, the current method of screening for treatment-related cardiomyopathy recommended by the Children's Oncology Group Guidelines, to cardiac magnetic resonance (CMR) imaging, the reference standard for left ventricular (LV) function. Cross-sectional, contemporaneous evaluation of LV structure and function by 2D and three-dimensional (3D) echocardiography and CMR imaging in 114 adult survivors of childhood cancer currently median age 39 years (range, 22 to 53 years) exposed to anthracycline chemotherapy and/or chest-directed radiation therapy. In this survivor population, 14% (n = 16) had an ejection fraction (EF) less than 50% by CMR. Survivors previously undiagnosed with cardiotoxicity (n = 108) had a high prevalence of EF (32%) and cardiac mass (48%) that were more than two standard deviations below the mean of normative CMR data. 2D echocardiography overestimated the mean EF of this population by 5%. Compared with CMR, 2D echocardiography (biplane method) had a sensitivity of 25% and a false-negative rate of 75% for detection of EF less than 50%, although 3D echocardiography had 53% and 47%, respectively. Twelve survivors (11%) had an EF less than 50% by CMR but were misclassified as ≥ 50% (range, 50% to 68%) by 2D echocardiography (biplane method). Detection of cardiomyopathy was improved (sensitivity, 75%) by using a higher 2D echocardiography cutoff (EF < 60%) to detect an EF less than 50% by the reference standard CMR. CMR identified a high prevalence of cardiomyopathy among adult survivors previously undiagnosed with cardiac disease. 2D echocardiography demonstrated limited screening performance. In this high-risk population, survivors with an EF 50% to 59% by 2D echocardiography should be considered for comprehensive cardiac assessment, which may include CMR.

Hybrid Phase ordering with Automatic Window Selection (HybridPAWS) improves respiratory-navigator efficiency during 3D late-gadolinium enhancement CMR in patients with chronic heart failure and irregular respiratory pattern

Summary Hybrid Phase ordering with Automatic Window Selection (HybridPAWS) improves respiratory-navigator efficiency during 3D late-gadolinium enhancement CMR in patients with chronic heart failure and irregular respiratory pattern. When there is a low gating efficiency (<40%) observed with standard respiratory-gated method, HybridPAWS technique resulted in a significantly greater improvement in navigator efficiency. Background Three-dimensional (3D) inversion recovery cardiac magnetic resonance (CMR) imaging is beginning to be utilised to characterise areas of late gadolinium enhancement (LGE) with high spatial resolution. This is important for tissue heterogeneity assessment in heart failure patients. The 3D CMR data are acquired during free breathing with the application of a respiratory navigator. However, a major challenge of its wider clinical application is the prolonged acquisition time in patients with irregular respiratory breathing pattern (Figure 1). The increased scan time can accentuate the effect of contrast kinetics on the quality of LGE-CMR images. In order to improve respiratory gating efficiency, we have implemented interleaved Radial Phase Encoding-Phase ordering with Automatic Window Selection for a Cartesian sampling scheme (HybridPAWS). With this