Cine Cardiac Magnetic Resonance Research Articles

Self-gated fetal cardiac MRI with tiny golden angle iGRASP: A feasibility study.

To develop and assess a technique for self-gated fetal cardiac cine magnetic resonance imaging (MRI) using tiny golden angle radial sampling combined with iGRASP (iterative Golden-angle RAdial Sparse Parallel) for accelerated acquisition based on parallel imaging and compressed sensing. Fetal cardiac data were acquired from five volunteers in gestational week 29-37 at 1.5T using tiny golden angles for eddy currents reduction. The acquired multicoil radial projections were input to a principal component analysis-based compression stage. The cardiac self-gating (CSG) signal for cardiac gating was extracted from the acquired radial projections and the iGRASP reconstruction procedure was applied. In all acquisitions, a total of 4000 radial spokes were acquired within a breath-hold of less than 15 seconds using a balanced steady-state free precession pulse sequence. The images were qualitatively compared by two independent observers (on a scale of 1-4) to a single midventricular cine image from metric optimized gating (MOG) and real-time acquisitions. For iGRASP and MOG images, good overall image quality (2.8 ± 0.4 and 2.6 ± 1.3, respectively, for observer 1; 3.6 ± 0.5 and 3.4 ± 0.9, respectively, for observer 2) and cardiac diagnostic quality (3.8 ± 0.4 and 3.4 ± 0.9, respectively, for observer 1; 3.6 ± 0.5 and 3.6 ± 0.9, respectively, for observer 2) were obtained, with visualized myocardial thickening over the cardiac cycle and well-defined myocardial borders to ventricular lumen and liver/lung tissue. For iGRASP, MOG, and real time, left ventricular lumen diameter (14.1 ± 2.2 mm, 14.2 ± 1.9 mm, 14.7 ± 1.1 mm, respectively) and wall thickness (2.7 ± 0.3 mm, 2.6 ± 0.3 mm, 3.0 ± 0.4, respectively) showed agreement and no statistically significant difference was found (all P > 0.05). Images with iGRASP tended to have higher overall image quality scores compared with MOG and particularly real-time images, albeit not statistically significant in this feasibility study (P > 0.99 and P = 0.12, respectively). Fetal cardiac cine MRI can be performed with iGRASP using tiny golden angles and CSG. Comparison with other fetal cardiac cine MRI methods showed that the proposed method produces high-quality fetal cardiac reconstructions. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:207-217.

Real-time cardiac magnetic resonance cine imaging with sparse sampling and iterative reconstruction for left-ventricular measures: Comparison with gold-standard segmented steady-state free precession

BackgroundSegmented cine imaging with a steady-state free-precession sequence (Cine-SSFP) is currently the gold standard technique for measuring ventricular volumes and mass, but due to multi breath-hold (BH) requirements, it is prone to misalignment of consecutive slices, time consuming and dependent on respiratory capacity. Real-time cine avoids those limitations, but poor spatial and temporal resolution of conventional sequences has prevented its routine application. We sought to examine the accuracy and feasibility of a newly developed real-time sequence with aggressive under-sampling of k-space using sparse sampling and iterative reconstruction (Cine-RT). MethodsStacks of short-axis cines were acquired covering both ventricles in a 1.5T system using gold standard Cine-SSFP and Cine-RT. Acquisition parameters for Cine-SSFP were: acquisition matrix of 224×196, temporal resolution of 39ms, retrospective gating, with an average of 8 heartbeats per slice and 1–2 slices/BH. For Cine-RT: acquisition matrix of 224×196, sparse sampling net acceleration factor of 11.3, temporal resolution of 41ms, prospective gating, real-time acquisition of 1 heart-beat/slice and all slices in one BH. LV contours were drawn at end diastole and systole to derive LV volumes and mass. ResultsForty-one consecutive patients (15 male; 41±17years) in sinus rhythm were successfully included. All images from Cine-SSFP and Cine-RT were considered to have excellent quality. Cine-RT-derived LV volumes and mass were slightly underestimated but strongly correlated with gold standard Cine-SSFP. Inter- and intra-observer analysis presented similar results between both sequences. ConclusionsCine-RT featuring sparse sampling and iterative reconstruction can achieve spatial and temporal resolution equivalent to Cine-SSFP, providing excellent image quality, with similar precision measurements and highly correlated and only slightly underestimated volume and mass values.

306 - First-pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

Abstract Purpose To assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methods Three hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. Results LVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. Conclusions The prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

Nonlinear profile order for three-dimensional hybrid radial acquisition applied to self-gated free-breathing cardiac cine MRI**Project supported by the National Natural Science Foundation of China (Grant Nos. 81501463, 61671026, 81571669, and 81671853), the Natural Science Foundation of Guangdong Province, China (Grant No. 2014A030310360), Guangdong Innovative Research Team Program of China (Grant No. 2011S013), the Basic Research Project of Shenzhen City, China

This paper presents a nonlinear profile order scheme for three-dimensional (3D) hybrid radial acquisition applied to self-gated, free-breathing cardiac cine magnetic resonance imaging (MRI). In self-gated, free-breathing cardiac cine MRI, respiratory and cardiac motions are unpredictable during acquisition, especially for retrospective reconstruction. Therefore, the non-uniformity of the k-space distribution is an issue of great concern during retrospective self-gated reconstruction. A nonlinear profile order with varying azimuthal increments was provided and compared with the existing golden ratio-based profile order. Optimal parameter values for the nonlinear formula were chosen based on simulations. The two profile orders were compared in terms of the k-space distribution and phantom and human image results. An approximately uniform distribution was obtained based on the nonlinear profile order for persons with various heart rates and breathing patterns. The nonlinear profile order provides more stable profile distributions and fewer streaking artifacts in phantom images. In a comparison of human cardiac cine images, the nonlinear profile order provided results comparable to those provided by the golden ratio-based profile order, and the images were suitable for diagnosis. In conclusion, the nonlinear profile order scheme was demonstrated to be insensitive to various motion patterns and more useful for retrospective reconstruction.

Changes of left ventricular mechanics after trans-catheter aortic valve implantation and surgical aortic valve replacement for severe aortic stenosis: A tissue-tracking cardiac magnetic resonance study

BackgroundLeft ventricular (LV) mechanics are impaired in patients with severe aortic stenosis (AS). The aim of the present study was to assess their changes early and late after trans-catheter aortic valve implantation (TAVI) and surgical aortic valve replacement (AVR) using cardiac magnetic resonance (CMR) tissue-tracking imaging. MethodsIn 59 patients with severe AS undergoing either TAVI (n=35) or surgical AVR (n=24), CMR with late gadolinium enhancement (LGE) imaging was performed before and early post-procedure to evaluate LV function and mass, and presence/extent of LGE. A third CMR scan was performed in 29 patients after a mean follow-up of 15±4months. Tissue-tracking analysis was applied to cine CMR images, to assess LV global longitudinal (GLS), circumferential (GCS) and radial (GRS) strains. ResultsThe TAVI and surgical AVR groups were similar with respect to baseline (p=0.14) and early post-procedure (p=0.16) LV ejection fraction. However, baseline LV GLS was significantly impaired in TAVI patients compared to surgical AVR patients (p=0.025). Early post-procedure, TAVI resulted in a significant improvement of LV GLS (p=0.003), while a significant worsening of LV GLS was observed early after surgical AVR (p=0.012). At longer term follow-up, both TAVI and surgical AVR groups experienced a significant reduction of LV mass and a significant improvement of LV myocardial mechanics in all the three directions. ConclusionsTreatment-specific differences in the changes of LV myocardial mechanics early after afterload release by TAVI and surgical AVR are present. Later, both interventions are associated with an improvement of LV myocardial deformation, alongside a regression of LV hypertrophy.

Accuracy and effectiveness of self-gating signals in free-breathing three-dimensional cardiac cine magnetic resonance imaging**Project supported by the National Natural Science Foundation of China (Grant Nos. 81501463, 61471349, 81671853, 81571669, and 61671026), the National High Technology Research and Development Program of China (Grant No. 2015AA043203), the Natural Science Foundation of Beijing, China (Grant No. 7162112), Guangdong Innovative Research Team Program of

Conventional multiple breath-hold two-dimensional (2D) balanced steady-state free precession (SSFP) presents many difficulties in cardiac cine magnetic resonance imaging (MRI). Recently, a self-gated free-breathing three-dimensional (3D) SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of self-gating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed.Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic (ECG) and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers.The results demonstrate an excellent correlation (P = 0, R > 0.99) between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac (H = 0, P > 0.10) and respiratory (H = 0, P > 0.44) motions. The difference between self-gating and externally monitored signals is not significant (two-tailed paired-sample t-test: H = 0, P > 0.90).The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors appear in some subjects while these errors are not found in self-gating signals.

Correcting motion in multiplanar cardiac magnetic resonance images.

BackgroundMisalignment in cardiac magnetic resonance (CMR) images can adversely affect three-dimensional left ventricle modelling and downstream quantitative analysis. Currently, there are two types of approaches for dealing with realignment and motion distortion problems, one image based and the other geometry based. Image-based approaches are limited by the inherent non-homogeneity and anisotropy of CMR images. Geometry-based approaches rely on idealized models and over-simplified assumptions. This study was motivated by the need for a robust and effective approach for correcting motion related distortions due to misalignment in CMR images.MethodsA cine cardiac magnetic resonance image sequence was acquired using our routine clinical imaging protocol. The left ventricular endocardium was delineated manually with software assistance on all long and short-axis images. Long and short-axis contours were projected onto a patient-based coordinate system and then realigned using iterative registration. The realigned contour points were used to reconstruct the shape of the left ventricle for quantitative validation.ResultsThe method was tested on five myocardial infarction patients whose images showed substantial misalignment. Realignment time was about 16 seconds per case, using a 2.5 GHz CPU desktop with obvious elimination of the distortion in the reconstructed model. Using the long-axis contour as a reference in evaluating the reconstructed models, it was apparent that the models with realigned contours had better accuracy than the non-realigned ones.ConclusionThis study presents a novel, geometry-based method for correcting motion distortions in CMR images. The method incorporates (1) manual delineation, (2) registration based on a generalized, iterative closest point algorithm, and (3) reconstruction of the shape of the left ventricle for quantitative validation. The effectiveness of our approach is corroborated both visually and by quantitative assessment. We envision the use of our method in current clinical practice as a means of improving accuracy in the evaluation of cardiac function.

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.

First pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

PurposeTo assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methodsThree hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. ResultsLVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. ConclusionsThe prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

Combining deep learning and level set for the automated segmentation of the left ventricle of the heart from cardiac cine magnetic resonance.

We introduce a new methodology that combines deep learning and level set for the automated segmentation of the left ventricle of the heart from cardiac cine magnetic resonance (MR) data. This combination is relevant for segmentation problems, where the visual object of interest presents large shape and appearance variations, but the annotated training set is small, which is the case for various medical image analysis applications, including the one considered in this paper. In particular, level set methods are based on shape and appearance terms that use small training sets, but present limitations for modelling the visual object variations. Deep learning methods can model such variations using relatively small amounts of annotated training, but they often need to be regularised to produce good generalisation. Therefore, the combination of these methods brings together the advantages of both approaches, producing a methodology that needs small training sets and produces accurate segmentation results. We test our methodology on the MICCAI 2009 left ventricle segmentation challenge database (containing 15 sequences for training, 15 for validation and 15 for testing), where our approach achieves the most accurate results in the semi-automated problem and state-of-the-art results for the fully automated challenge.

Pheochromocytoma Is Characterized by Catecholamine-Mediated Myocarditis, Focal and Diffuse Myocardial Fibrosis, and Myocardial Dysfunction

BackgroundPheochromocytoma is associated with catecholamine-induced cardiac toxicity, but the extent and nature of cardiac involvement in clinical cohorts is not well-characterized. ObjectivesThis study characterized the cardiac phenotype in patients with pheochromocytoma using cardiac magnetic resonance (CMR). MethodsA total of 125 subjects were studied, including patients with newly diagnosed pheochromocytoma (n = 29), patients with previously surgically cured pheochromocytoma (n = 31), healthy control subjects (n = 51), and hypertensive control subjects (HTN) (n = 14), using CMR (1.5-T) cine, strain imaging by myocardial tagging, late gadolinium enhancement, and native T1 mapping (Shortened Modified Look-Locker Inversion recovery [ShMOLLI]). ResultsPatients who were newly diagnosed with pheochromocytoma, compared with healthy and HTN control subjects, had impaired left ventricular (LV) ejection fraction (<56% in 38% of patients), peak systolic circumferential strain (p < 0.05), and diastolic strain rate (p < 0.05). They had higher myocardial T1 (974 ± 25 ms, as compared with 954 ± 16 ms in healthy and 958 ± 23 ms in HTN subjects; p < 0.05), areas of myocarditis (median 22% LV with T1 >990 ms, as compared with 1% in healthy and 2% in HTN subjects; p < 0.05), and focal fibrosis (59% had nonischemic late gadolinium enhancement, as compared with 14% in HTN subjects). Post-operatively, impaired LV ejection fraction typically normalized, but systolic and diastolic strain impairment persisted. Focal fibrosis (median 5% LV) and T1 abnormalities (median 12% LV) remained, the latter of which may suggest some diffuse fibrosis. Previously cured patients demonstrated abnormal diastolic strain rate (p < 0.001), myocardial T1 (median 12% LV), and small areas of focal fibrosis (median 1% LV). LV mass index was increased in HTN compared with healthy control subjects (p < 0.05), but not in the 2 pheochromocytoma groups. ConclusionsThis first systematic CMR study characterizing the cardiac phenotype in pheochromocytoma showed that cardiac involvement was frequent and, for some variables, persisted after curative surgery. These effects surpass those of hypertensive heart disease alone, supporting a direct role of catecholamine toxicity that may produce subtle but long-lasting myocardial alterations.

Doppler Ultrasound Triggering for Cardiovascular MRI at 3T in a Healthy Volunteer Study.

Purpose:Electrocardiogram (ECG) triggering for cardiac magnetic resonance (CMR) may be influenced by electromagnetic interferences with increasing magnetic field strength. The aim of this study was to evaluate the performance of Doppler ultrasound (DUS) as an alternative trigger technique for CMR in comparison to ECG and pulse oximetry (POX) at 3T and using different sequence types.Methods:Balanced turbo field echo two-dimensional (2D) short axis cine CMR and 2D phase-contrast angiography of the ascending aorta was performed in 11 healthy volunteers at 3T using ECG, DUS, and POX for cardiac triggering. DUS and POX triggering were compared to the reference standard of ECG in terms of trigger quality (trigger detection and temporal variability), image quality [endocardial blurring (EB)], and functional measurements [left ventricular (LV) volumetry and aortic blood flow velocimetry].Results:Trigger signal detection and temporal variability did not differ significantly between ECG/DUS (I = 0.6) and ECG/POX (P = 0.4). Averaged EB was similar for ECG, DUS, and POX (pECG/DUS = 0.4, pECG/POX = 0.9). Diastolic EB was significantly decreased for DUS in comparison to ECG (P = 0.02) and POX (P = 0.04). The LV function assessment and aortic blood flow were not significantly different.Conclusion:This study demonstrated the feasibility of DUS for gating human CMR at 3T. The magnetohydrodynamic effect did not significantly disturb ECG triggering in this small healthy volunteer study. DUS showed a significant improvement in diastolic EB but could not be identified as a superior trigger method. The potential benefit of DUS has to be evaluated in a larger clinical patient population.

Longitudinal fiber dysfunction assessed during cine-cardiac magnetic resonance imaging is an independent predictor of adverse cardiac events

Background Left ventricular systole involves coordinated contraction of longitudinal, circumferential, and radial myocardial fibers. Longitudinal fiber dysfunction appears to be an early marker for a number of pathological states. We hypothesized that reduced mitral annular plane systolic excursion (MAPSE) measured during cine-Cardiac Magnetic Resonance (CMR) imaging reflects changes in longitudinal fiber function and may be an early marker for adverse cardiovascular outcomes.

Differences in left ventricular strain measurements between cine DENSE cardiac magnetic resonance and SSFP feature tracking

Differences in left ventricular strain measurements between cine DENSE cardiac magnetic resonance and SSFP feature tracking

The accuracy and effectiveness of self-gating signals in free-breathing 3D cardiac cine MRI

Background Conventional cardiac cine magnetic resonance imaging (MRI) is typically based on the segmented data acquired by breath-hold 2D balanced steady-state free procession (SSFP) pulse sequence [1]. However, the slice misregistration caused by the variation of breath holding positions could compromise the effectiveness of 2D SSFP, and breath-hold makes it difficult for pediatric patients or patients who suffer from congestive heart failure to cooperate [2]. Recently, respiratory and cardiac selfgated free-breathing (FB) cardiac cine MRI have been proposed for overcoming these barriers [3]. This approach could provide similar image quality and functional measurements without using electrocardiographic (ECG) or any peripheral equipment compared with 2D SSFP. However, the precision comparison between the self-gating signals and the external signals needs to be studied systematically.

Myocardial strain assessment by cine cardiac magnetic resonance imaging using non-rigid registration

AimsTo evaluate a novel post-processing method for assessment of longitudinal mid-myocardial strain in standard cine cardiac magnetic resonance (CMR) imaging sequences. Methods and resultsCine CMR imaging and tagged cardiac magnetic resonance imaging (TMRI) were performed in 15 patients with acute myocardial infarction (AMI) and 15 healthy volunteers served as control group. A second group of 37 post-AMI patients underwent both cine CMR and late gadolinium enhancement (LGE) CMR exams. Speckle tracking echocardiography (STE) was performed in 36 of these patients. Cine CMR, TMRI and STE were analyzed to obtain longitudinal strain. LGE-CMR datasets were analyzed to evaluate scar extent. Comparison of peak systolic strain (PSS) measured from CMR and TMRI yielded a strong correlation (r=0.86, p<0.001). PSS measured from CMR and STE correlated well (r=0.75, p<0.001). A cutoff longitudinal PSS value of −13.14% differentiated non-infarction from any infarcted myocardium, with a sensitivity of 93% and a specificity of 89% (area under curve (AUC) 0.95). PSS value of −9.39% differentiated non-transmural from transmural infarcted myocardium, with a sensitivity of 75% and a specificity of 67% (AUC 0.78). ConclusionThe present study showed a novel off-line post-processing method for segmental longitudinal strain analysis in mid-myocardium layer based on cine CMR data. The method was found to be highly correlated with strain measurements obtained by TMRI and STE. This tool allows accurate discrimination between different transmurality states of myocardial infarction.

Abstract 15856: Left Ventricular Longitudinal Contractility Measured During Routine Cine-cardiac Magnetic Resonance Imaging is an Independent Predictor of Adverse Cardiac Events

Background: Left ventricular systole involves coordinated contraction of longitudinal, circumferential, and radial myocardial fibers. Longitudinal fiber dysfunction appears to be an early marker for a number of pathological states. We hypothesized that reduced mitral annular plane systolic excursion (MAPSE) measured during cine-Cardiac Magnetic Resonance (CMR) imaging reflects changes in longitudinal fiber function and may be an early marker for adverse cardiovascular outcomes. Methods: 400 consecutive patients with known or suspected coronary artery disease undergoing CMR were prospectively enrolled. Lateral MAPSE was measured in the 4-chamber cine view by two independent observers. Patients were prospectively followed for major adverse cardiac events (MACE) - death, non-fatal myocardial infarction, hospitalization for heart failure or chest pain, and late revascularization. Cox proportional hazards regression modeling was used to identify factors independently associated with MACE. Results: The mean age of the study population was 58(±15) years, with a mean ejection fraction of 59(±14%). 31% of the individuals had known coronary artery disease and 33% were diabetic. 72 MACE occurred during a median follow-up of 14.5 months. By Kaplan-Meier analysis, patients with lateral MAPSE ≤1.11cm (median) experienced significantly higher incidence of MACE than patients with a MAPSE &gt;1.11cm (p = 0.0270) (Figure). After adjustment for established predictors (ejection fraction, age, sex, diabetes, hyperlipidemia, smoking, hypertension, late gadolinium enhancement) lateral MAPSE remained a significant independent predictor of MACE (HR=2.43 per cm decrease; p=0.037). Conclusions: Reduced longitudinal fiber function assessed with lateral MAPSE during cine-CMR is an independent predictor of MACE in patients with known or suspected coronary artery disease. Figure: Kaplan-Meier curves for MACE in patients with MAPSE above and below the median.

Abstract 13071: Computational Simulation of Virtual Ross Operation

Background: Unlike other bioprosthetic and mechanical valve replacement strategies, the Ross procedure has been shown to normalize patient survival comparable to an age-matched general population. However, one of the main limitations of the Ross procedure is the need for reoperation due to autograft dilatation or aortic insufficiency. The objective of this study was to develop a patient-specific virtual Ross operation with full root-replacement technique using computational simulation to investigate pulmonary autograft biomechanics early after surgery. Methods: A patient scheduled for Ross procedure underwent preoperative cine-cardiac magnetic resonance imaging (MRI). MRI lumen geometry was used to create surface contour meshes of aortic sinuses and pulmonary autograft. Using reverse engineering approach, zero-pressure geometries of aortic root and pulmonary autograft were created; unloaded wall thickness and autograft material properties were included. Using LS-DYNA software, simulations were performed of surgical suturing aortic root replacement with a pulmonary autograft. Sutured autograft and remaining aorta were then loaded to systemic pressure. Results: Average von Mises stress increased from 62kPa preoperatively in the native pulmonary root in situ at pulmonary pressure to 373.8kPa in the autograft as root replacement at systemic pressure, while postoperative von Mises stress in remaining aortic wall was 107.1kPa (fig 1). Conclusions: We performed patient-specific virtual Ross operation using computational simulation. Increased stress in pulmonary autograft indicated areas prone to possible structural failure. Reinforcement in these regions to support autograft wall may reduce future reoperation. Such patient-specific simulations to analyze stress concentrations may be an effective tool to optimize surgical techniques and determine patient-specific risk of aneurysm formation.

Right Ventricular Strain and Dyssynchrony Assessment in Arrhythmogenic Right Ventricular Cardiomyopathy: Cardiac Magnetic Resonance Feature-Tracking Study.

Analysis of right ventricular (RV) regional dysfunction by cardiac magnetic resonance (CMR) imaging in arrhythmogenic RV cardiomyopathy (ARVC) may be inadequate because of the complex contraction pattern of the RV. Aim of this study was to determine the use of RV strain and dyssynchrony assessment in ARVC using feature-tracking CMR analysis. Thirty-two consecutive patients with ARVC referred to CMR imaging were included. Thirty-two patients with idiopathic RV outflow tract arrhythmias and 32 control subjects, matched for age and sex to the ARVC group, were included for comparison purpose. CMR imaging was performed to assess biventricular function; feature-tracking analysis was applied to the cine CMR images to assess regional and global longitudinal, circumferential, and radial RV strains and RV dyssynchrony (defined as the SD of the time-to-peak strain of the RV segments). RV global longitudinal strain (-17±5% versus -26±6% versus -29±6%; P<0.001), global circumferential strain (-9±4% versus -12±4% versus -13±5%; P=0.001), and global radial strain (18 [12-26]% versus 22 [15-32]% versus 27 [20-39]%; P=0.015) were significantly lower and SD of the time-to-peak RV strain in all 3 directions were significantly higher among patients with ARVC compared with patients with RV outflow tract arrhythmias and controls. RV global longitudinal strain >-23.2%, SD of the time-to-peak RV longitudinal strain >113.1 ms, and SD of the time-to-peak RV circumferential strain >177.1 ms allowed correct identification of 88%, 75%, and 63% of ARVC patients with no or only minor CMR criteria for ARVC diagnosis. Strain analysis by feature-tracking CMR helps to objectively quantify global and regional RV dysfunction and RV dyssynchrony in patients with ARVC and provides incremental value over conventional cine CMR imaging.

Compressed sensing reconstruction of cardiac cine MRI using golden angle spiral trajectories

In dynamic cardiac cine Magnetic Resonance Imaging (MRI), the spatiotemporal resolution is limited by the low imaging speed. Compressed sensing (CS) theory has been applied to improve the imaging speed and thus the spatiotemporal resolution. The purpose of this paper is to improve CS reconstruction of under sampled data by exploiting spatiotemporal sparsity and efficient spiral trajectories.We extend k–t sparse algorithm to spiral trajectories to achieve high spatio temporal resolutions in cardiac cine imaging. We have exploited spatiotemporal sparsity of cardiac cine MRI by applying a 2D+time wavelet-Fourier transform. For efficient coverage of k-space, we have used a modified version of multi shot (interleaved) spirals trajectories. In order to reduce incoherent aliasing artifact, we use different random undersampling pattern for each temporal frame. Finally, we have used nonuniform fast Fourier transform (NUFFT) algorithm to reconstruct the image from the non-uniformly acquired samples.The proposed approach was tested in simulated and cardiac cine MRI data. Results show that higher acceleration factors with improved image quality can be obtained with the proposed approach in comparison to the existing state-of-the-art method.The flexibility of the introduced method should allow it to be used not only for the challenging case of cardiac imaging, but also for other patient motion where the patient moves or breathes during acquisition.