234 results found
Fair MJ, Gatehouse PD, Firmin DN, 2021, Minimisation of slab-selective radiofrequency excitation pulse durations constrained by an acceptable aliasing coefficient, MAGNETIC RESONANCE IMAGING, Vol: 81, Pages: 94-100, ISSN: 0730-725X
Bermejo IA, Bautista-Rodriguez C, Fraisse A, et al., 2021, Short-Term sequelae of Multisystem Inflammatory Syndrome in Children Assessed by CMR, JACC-CARDIOVASCULAR IMAGING, Vol: 14, Pages: 1666-1667, ISSN: 1936-878X
Kuang M, Wu Y, Alonso-Álvarez D, et al., 2021, Three-dimensional embedded attentive RNN (3D-EAR) segmentor for leftventricle delineation from myocardial velocity mapping, Publisher: arXiv
Myocardial Velocity Mapping Cardiac MR (MVM-CMR) can be used to measureglobal and regional myocardial velocities with proved reproducibility. Accurateleft ventricle delineation is a prerequisite for robust and reproduciblemyocardial velocity estimation. Conventional manual segmentation on thisdataset can be time-consuming and subjective, and an effective fully automateddelineation method is highly in demand. By leveraging recently proposed deeplearning-based semantic segmentation approaches, in this study, we propose anovel fully automated framework incorporating a 3D-UNet backbone architecturewith Embedded multichannel Attention mechanism and LSTM based Recurrent neuralnetworks (RNN) for the MVM-CMR datasets (dubbed 3D-EAR segmentor). The proposedmethod also utilises the amalgamation of magnitude and phase images as input torealise an information fusion of this multichannel dataset and exploring thecorrelations of temporal frames via the embedded RNN. By comparing the baselinemodel of 3D-UNet and ablation studies with and without embedded attentive LSTMmodules and various loss functions, we can demonstrate that the proposed modelhas outperformed the state-of-the-art baseline models with significantimprovement.
Raphael C, Mitchell F, Kanaganayagam G, et al., 2021, Cardiovascular magnetic resonance predictors of heart failure in hypertrophic cardiomyopathy: the role of myocardial replacement fibrosis and the microcirculation, Journal of Cardiovascular Magnetic Resonance, Vol: 26, ISSN: 1097-6647
IntroductionHeart failure (HF) in hypertrophic cardiomyopathy (HCM) is associated with high morbidity and mortality. Predictors of HF, in particular the role of myocardial fibrosis and microvascular ischemia remain unclear. We assessed the predictive value of cardiovascular magnetic resonance (CMR) for development of HF in HCM in an observational cohort study.MethodsSerial patients with HCM underwent CMR, including adenosine first-pass perfusion, left atrial (LA) and left ventricular (LV) volumes indexed to body surface area (i) and late gadolinium enhancement (%LGE- as a % of total myocardial mass). We used a composite endpoint of HF death, cardiac transplantation, and progression to NYHA class III/IV.ResultsA total of 543 patients with HCM underwent CMR, of whom 94 met the composite endpoint at baseline. The remaining 449 patients were followed for a median of 5.6 years. Thirty nine patients (8.7%) reached the composite endpoint of HF death (n = 7), cardiac transplantation (n = 2) and progression to NYHA class III/IV (n = 20). The annual incidence of HF was 2.0 per 100 person-years, 95% CI (1.6–2.6). Age, previous non-sustained ventricular tachycardia, LV end-systolic volume indexed to body surface area (LVESVI), LA volume index ; LV ejection fraction, %LGE and presence of mitral regurgitation were significant univariable predictors of HF, with LVESVI (Hazard ratio (HR) 1.44, 95% confidence interval (95% CI) 1.16–1.78, p = 0.001), %LGE per 10% (HR 1.44, 95%CI 1.14–1.82, p = 0.002) age (HR 1.37, 95% CI 1.06–1.77, p = 0.02) and mitral regurgitation (HR 2.6, p = 0.02) remaining independently predictive on multivariable analysis. The presence or extent of inducible perfusion defect assessed using a visual score did not predict outcome (p = 0.16, p = 0.27 respectively).DiscussionThe annual incidence of HF in a contemporary ambulatory HCM population undergoing CMR
Wu Y, Hatipoglu S, Alonso-Álvarez D, et al., 2021, Fast and automated segmentation for the three-directional multi-slice cine myocardial velocity mapping, Diagnostics, Vol: 11, ISSN: 2075-4418
Three-directional cine multi-slice left ventricular myocardial velocity mapping (3Dir MVM) is a cardiac magnetic resonance (CMR) technique that allows the assessment of cardiac motion in three orthogonal directions. Accurate and reproducible delineation of the myocardium is crucial for accurate analysis of peak systolic and diastolic myocardial velocities. In addition to the conventionally available magnitude CMR data, 3Dir MVM also provides three orthogonal phase velocity mapping datasets, which are used to generate velocity maps. These velocity maps may also be used to facilitate and improve the myocardial delineation. Based on the success of deep learning in medical image processing, we propose a novel fast and automated framework that improves the standard U-Net-based methods on these CMR multi-channel data (magnitude and phase velocity mapping) by cross-channel fusion with an attention module and the shape information-based post-processing to achieve accurate delineation of both epicardial and endocardial contours. To evaluate the results, we employ the widely used Dice Scores and the quantification of myocardial longitudinal peak velocities. Our proposed network trained with multi-channel data shows superior performance compared to standard U-Net-based networks trained on single-channel data. The obtained results are promising and provide compelling evidence for the design and application of our multi-channel image analysis of the 3Dir MVM CMR data.
Wu Y, Hatipoglu S, Alonso-Álvarez D, et al., 2021, Automated multi-channel segmentation for the 4D myocardial velocity mapping cardiac MR, Medical Imaging 2021: Computer-Aided Diagnosis, Publisher: SPIE, Pages: 1-7
Four-dimensional (4D) left ventricular myocardial velocity mapping (MVM) is a cardiac magnetic resonance (CMR) technique that allows assessment of cardiac motion in three orthogonal directions. Accurate and reproducible delineation of the myocardium is crucial for accurate analysis of peak systolic and diastolic myocardial velocities. In addition to the conventionally available magnitude CMR data, 4D MVM also acquires three velocity-encoded phase datasets which are used to generate velocity maps. These can be used to facilitate and improve myocardial delineation. Based on the success of deep learning in medical image processing, we propose a novel automated framework that improves the standard U-Net based methods on these CMR multi-channel data (magnitude and phase) by cross-channel fusion with attention module and shape information based post-processing to achieve accurate delineation of both epicardium and endocardium contours. To evaluate the results, we employ the widely used Dice scores and the quantification of myocardial longitudinal peak velocities. Our proposed network trained with multi-channel data shows enhanced performance compared to standard UNet based networks trained with single-channel data. Based on the results, our method provides compelling evidence for the design and application for the multi-channel image analysis of the 4D MVM CMR data.
Fair MJ, Gatehouse PD, Reyes E, et al., 2020, Initial investigation of free-breathing 3D whole-heart stress myocardial perfusion MRI., Glob Cardiol Sci Pract, Vol: 2020, ISSN: 2305-7823
Objective: Myocardial first-pass perfusion imaging with MRI is well-established clinically. However, it is potentially weakened by limited myocardial coverage compared to nuclear medicine. Clinical evaluations of whole-heart MRI perfusion by 3D methods, while promising, have to date had the limit of breathhold requirements at stress. This work aims to develop a new free-breathing 3D myocardial perfusion method, and to test its performance in a small patient population. Methods: This work required tolerance to respiratory motion for stress investigations, and therefore employed a "stack-of-stars" hybrid Cartesian-radial MRI acquisition method. The MRI sequence was highly optimised for rapid acquisition and combined with a compressed sensing reconstruction. Stress and rest datasets were acquired in four healthy volunteers, and in six patients with coronary artery disease (CAD), which were compared against clinical reference information. Results: This free-breathing method produced datasets that appeared consistent with clinical reference data in detecting moderate-to-strong induced perfusion abnormalities. However, the majority of the mild defects identified clinically were not detected by the method, potentially due to the presence of transient myocardial artefacts present in the images. Discussion: The feasibility of detecting CAD using this 3D first-pass perfusion sequence during free-breathing is demonstrated. Good agreement on typical moderate-to-strong CAD cases is promising, however, questions still remain on the sensitivity of the technique to milder cases.
Raphael CE, Liew AC, Mitchell F, et al., 2020, Predictors and Mechanisms of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy, AMERICAN JOURNAL OF CARDIOLOGY, Vol: 136, Pages: 140-148, ISSN: 0002-9149
Mendes JK, Adluru G, Likhite D, et al., 2020, Quantitative 3D myocardial perfusion with an efficient arterial input function, MAGNETIC RESONANCE IN MEDICINE, Vol: 83, Pages: 1949-1963, ISSN: 0740-3194
Captur G, Bhandari A, Bruehl R, et al., 2020, T-1 mapping performance and measurement repeatability: results from the multi-national T-1 mapping standardization phantom program (T1MES), JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE, Vol: 22, ISSN: 1097-6647
Gulati A, Ismail TF, Ali A, et al., 2019, Microvascular Dysfunction in Dilated Cardiomyopathy A Quantitative Stress Perfusion Cardiovascular Magnetic Resonance Study, JACC-CARDIOVASCULAR IMAGING, Vol: 12, Pages: 1699-1708, ISSN: 1936-878X
Ghonim S, Gatehouse PD, Giblin G, et al., 2019, Can RV optimised native T1 mapping and ECV add clinical value in repaired tetralogy of Fallot?, Publisher: OXFORD UNIV PRESS, Pages: 204-205, ISSN: 2047-2404
Hofman MBM, Rodenburg MJA, Bloch KM, et al., 2019, In-vivo validation of interpolation-based phase offset correction in cardiovascular magnetic resonance flow quantification: a multi-vendor, multi-center study, JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE, Vol: 21, ISSN: 1097-6647
Gorodezky M, Ferreira P, Nielles-Vallespin S, et al., 2019, High resolution in-vivo DT-CMR using an interleaved variable density spiral STEAM sequence, Magnetic Resonance in Medicine, Vol: 81, Pages: 1580-1594, ISSN: 0740-3194
Purpose: Diffusion tensor cardiovascular magnetic resonance (DT-CMR) has a limited spatial resolution. Thepurpose of this study was to demonstrate high-resolution DT-CMR using a segmented variable density spiralsequence with correction for motion, off-resonance and T2* related blurring.Methods: A single-shot STEAM EPI DT-CMR sequence at 2.8x2.8x8mm3 and 1.8x1.8x8mm3 was compared to asingle shot spiral at 2.8x2.8x8mm3 and an interleaved spiral sequence at 1.8x1.8x8mm3resolution in 10 healthyvolunteers at peak-systole and diastasis. Motion-induced phase was corrected using the densely sampledcentral k-space data of the spirals. STEAM field maps and T2* measures were obtained using a pair ofstimulated echoes each with a double spiral readout, the first used to correct the motion-induced phase of thesecond.Results: The high resolution spiral sequence produced similar DT-CMR results and quality measures to thestandard resolution sequence in both cardiac phases. Residual differences in fractional anisotropy and helixangle gradient between the resolutions could be due to spatial resolution and/or signal to noise ratio. The dataquality increased after both motion-induced phase correction and off-resonance correction and sharpnessincreased after T2* correction. The high resolution EPI sequence failed to provide sufficient data quality forDT-CMR reconstruction.Conclusion: In this study an in-vivo DT-CMR acquisition at 1.8x1.8mm2in-plane resolution was demonstratedusing a segmented spiral STEAM sequence. The motion-induced phase and off-resonance corrections areessential for high resolution spiral DT-CMR. Segmented variable density spiral STEAM was found to be theoptimal method for acquiring high resolution DT-CMR data.
Ghonim S, Gatehouse PD, Gatzoulis MA, et al., 2018, Is cardiovascular magnetic resonance measurement of diffuse fibrosis ready for clinical use in the systemic RV?, International Journal of Cardiology, Vol: 271, Pages: 66-67, ISSN: 0167-5273
Vassiliou VS, Cameron D, Prasad SK, et al., 2018, Magnetic resonance imaging: Physics basics for the cardiologist, JRSM CARDIOVASCULAR DISEASE, Vol: 7, ISSN: 2048-0040
Magnetic resonance imaging physics can be a complex and challenging topic for the practising cardiologist. Its evolving nature and the increasing number of novel sequences used in clinical scanning have been topics of excellent reviews; however, the basic understanding of physics underlying the creation of images remains difficult for many cardiologists. In this review, we go back to the basic physics theories underpinning magnetic resonance and explain their application and use in achieving good quality cardiac imaging, whilst describing established and novel magnetic resonance sequences. By understanding these basic principles, it is anticipated that cardiologists and other health professionals will then appreciate more advanced physics manuscripts on cardiac scanning and novel sequences.
Scott AD, Nielles-Vallespin S, Ferreira P, et al., 2018, An in-vivo comparison of stimulated-echo and motion compensated spin-echo sequences for 3T diffusion tensor cardiovascular magnetic resonance at multiple cardiac phases, Journal of Cardiovascular Magnetic Resonance, Vol: 20, ISSN: 1097-6647
BackgroundStimulated-echo (STEAM) and, more recently, motion-compensated spin-echo (M2-SE) techniques have been used for in-vivo diffusion tensor cardiovascular magnetic resonance (DT-CMR) assessment of cardiac microstructure. The two techniques differ in the length scales of diffusion interrogated, their signal-to-noise ratio efficiency and sensitivity to both motion and strain. Previous comparisons of the techniques have used high performance gradients at 1.5 T in a single cardiac phase. However, recent work using STEAM has demonstrated novel findings of microscopic dysfunction in cardiomyopathy patients, when DT-CMR was performed at multiple cardiac phases. We compare STEAM and M2-SE using a clinical 3 T scanner in three potentially clinically interesting cardiac phases.MethodsBreath hold mid-ventricular short-axis DT-CMR was performed in 15 subjects using M2-SE and STEAM at end-systole, systolic sweet-spot and diastasis. Success was defined by ≥50% of the myocardium demonstrating normal helix angles. From successful acquisitions DT-CMR results relating to tensor orientation, size and shape were compared between sequences and cardiac phases using non-parametric statistics. Strain information was obtained using cine spiral displacement encoding with stimulated echoes for comparison with DT-CMR results.ResultsAcquisitions were successful in 98% of STEAM and 76% of M2-SE cases and visual helix angle (HA) map scores were higher for STEAM at the sweet-spot and diastasis. There were significant differences between sequences (p < 0.05) in mean diffusivity (MD), fractional anisotropy (FA), tensor mode, transmural HA gradient and absolute second eigenvector angle (E2A). Differences in E2A between systole and diastole correlated with peak radial strain for both sequences (p ≤ 0.01).ConclusionM2-SE and STEAM can be performed equally well at peak systole at 3 T using standard gradients, but at the sweet-spot and diastole STEAM is more rel
Nyktari E, Vassiliou VS, Arzanauskaite M, et al., 2017, Challenging Occam's Razor: An Unusual Combination of Sarcoidosis and Amyloidosis. The Value of Cardiac Magnetic Resonance Imaging in Infiltrative Cardiomyopathies, CANADIAN JOURNAL OF CARDIOLOGY, Vol: 33, ISSN: 0828-282X
Cameron D, Vassiliou VS, Higgins DM, et al., 2017, Towards accurate and precise T 1 and extracellular volume mapping in the myocardium: a guide to current pitfalls and their solutions, Magnetic Resonance Materials in Physics, Biology and Medicine, Vol: 31, Pages: 143-163, ISSN: 0968-5243
Mapping of the longitudinal relaxation time (T 1) and extracellular volume (ECV) offers a means of identifying pathological changes in myocardial tissue, including diffuse changes that may be invisible to existing T 1-weighted methods. This technique has recently shown strong clinical utility for pathologies such as Anderson-Fabry disease and amyloidosis and has generated clinical interest as a possible means of detecting small changes in diffuse fibrosis; however, scatter in T 1 and ECV estimates offers challenges for detecting these changes, and bias limits comparisons between sites and vendors. There are several technical and physiological pitfalls that influence the accuracy (bias) and precision (repeatability) of T 1 and ECV mapping methods. The goal of this review is to describe the most significant of these, and detail current solutions, in order to aid scientists and clinicians to maximise the utility of T 1 mapping in their clinical or research setting. A detailed summary of technical and physiological factors, issues relating to contrast agents, and specific disease-related issues is provided, along with some considerations on the future directions of the field.
Vassiliou V, Wassilew K, Cameron D, et al., 2017, Identification of myocardial diffuse fibrosis by 11 heartbeat MOLLI T1 mapping: Averaging to improve precision and correlation with collagen volume fraction, Magnetic Resonance Materials in Physics Biology and Medicine, Vol: 31, Pages: 101-113, ISSN: 0968-5243
ObjectivesOur objectives involved identifying whether repeated averaging in basal and mid left ventricular myocardial levels improves precision and correlation with collagen volume fraction for 11 heartbeat MOLLI T1 mapping versus assessment at a single ventricular level.Materials and methodsFor assessment of T1 mapping precision, a cohort of 15 healthy volunteers underwent two CMR scans on separate days using an 11 heartbeat MOLLI with a 5(3)3 beat scheme to measure native T1 and a 4(1)3(1)2 beat post-contrast scheme to measure post-contrast T1, allowing calculation of partition coefficient and ECV. To assess correlation of T1 mapping with collagen volume fraction, a separate cohort of ten aortic stenosis patients scheduled to undergo surgery underwent one CMR scan with this 11 heartbeat MOLLI scheme, followed by intraoperative tru-cut myocardial biopsy. Six models of myocardial diffuse fibrosis assessment were established with incremental inclusion of imaging by averaging of the basal and mid-myocardial left ventricular levels, and each model was assessed for precision and correlation with collagen volume fraction.ResultsA model using 11 heart beat MOLLI imaging of two basal and two mid ventricular level averaged T1 maps provided improved precision (Intraclass correlation 0.93 vs 0.84) and correlation with histology (R2 = 0.83 vs 0.36) for diffuse fibrosis compared to a single mid-ventricular level alone. ECV was more precise and correlated better than native T1 mapping.ConclusionT1 mapping sequences with repeated averaging could be considered for applications of 11 heartbeat MOLLI, especially when small changes in native T1/ECV might affect clinical management.
Ghonim S, Voges I, Gatehouse PD, et al., 2017, Myocardial Architecture, Mechanics, and Fibrosis in Congenital Heart Disease, Frontiers in Cardiovascular Medicine, Vol: 4, ISSN: 2297-055X
Congenital heart disease (CHD) is the most common category of birth defect, affecting1% of the population and requiring cardiovascular surgery in the first months of lifein many patients. Due to advances in congenital cardiovascular surgery and patientmanagement, most children with CHD now survive into adulthood. However, residualand postoperative defects are common resulting in abnormal hemodynamics, whichmay interact further with scar formation related to surgical procedures. Cardiovascularmagnetic resonance (CMR) has become an important diagnostic imaging modality inthe long-term management of CHD patients. It is the gold standard technique to assessventricular volumes and systolic function. Besides this, advanced CMR techniques allowthe acquisition of more detailed information about myocardial architecture, ventricularmechanics, and fibrosis. The left ventricle (LV) and right ventricle have unique myocardialarchitecture that underpins their mechanics; however, this becomes disorganized underconditions of volume and pressure overload. CMR diffusion tensor imaging is able tointerrogate non-invasively the principal alignments of microstructures in the left ventricularwall. Myocardial tissue tagging (displacement encoding using stimulated echoes) andfeature tracking are CMR techniques that can be used to examine the deformation andstrain of the myocardium in CHD, whereas 3D feature tracking can assess the twistingmotion of the LV chamber. Late gadolinium enhancement imaging and more recently T1mapping can help in detecting fibrotic myocardial changes and evolve our understandingof the pathophysiology of CHD patients. This review not only gives an overview aboutavailable or emerging CMR techniques for assessing myocardial mechanics and fibrosisbut it also describes their clinical value and how they can be used to detect abnormalitiesin myocardial architecture and mechanics in CHD patients.
Khan TZ, Hsu LY, Arai AE, et al., 2017, Apheresis as novel treatment for refractory angina with raised lipoprotein(a): a randomised controlled trial, European Heart Journal, Vol: 38, Pages: 1561-1569, ISSN: 1522-9645
AimsTo determine the clinical impact of lipoprotein apheresis in patients with refractory angina and raised lipoprotein(a) > 500 mg/L on the primary end point of quantitative myocardial perfusion, as well as secondary end points including atheroma burden, exercise capacity, symptoms, and quality of life.MethodsWe conducted a single-blinded randomized controlled trial in 20 patients with refractory angina and raised lipoprotein(a) > 500 mg/L, with 3 months of blinded weekly lipoprotein apheresis or sham, followed by crossover. The primary endpoint was change in quantitative myocardial perfusion reserve (MPR) assessed by cardiovascular magnetic resonance. Secondary endpoints included measures of atheroma burden, exercise capacity, symptoms and quality of life.ResultsThe primary endpoint, namely MPR, increased following apheresis (0.47; 95% CI 0.31–0.63) compared with sham (−0.16; 95% CI − 0.33–0.02) yielding a net treatment increase of 0.63 (95% CI 0.37–0.89; P < 0.001 between groups). Improvements with apheresis compared with sham also occurred in atherosclerotic burden as assessed by total carotid wall volume (P < 0.001), exercise capacity by the 6 min walk test (P = 0.001), 4 of 5 domains of the Seattle angina questionnaire (all P < 0.02) and quality of life physical component summary by the short form 36 survey (P = 0.001).ConclusionLipoprotein apheresis may represent an effective novel treatment for patients with refractory angina and raised lipoprotein(a) improving myocardial perfusion, atheroma burden, exercise capacity and symptoms.
Lota AS, Gatehouse PD, Mohiaddin RH, 2017, T2 mapping and T2*imaging in heart failure, Heart Failure Reviews, Vol: 22, Pages: 431-440, ISSN: 1382-4147
Cardiovascular magnetic resonance (CMR) is aversatile imaging modality that enables aetiological assessmentand provides additional information to that of standardechocardiography in a significant proportion of patients withheart failure. In addition to highly accurate and reproducibleassessment of ventricular volumes and replacement fibrosis,multiparametric mapping techniques have rapidly evolved tofurther expand the diagnostic and prognostic applications invarious conditions ranging from acute inflammatory and ischaemiccardiomyopathy, to cardiac involvement in systemicdiseases such as sarcoidosis and iron overload cardiomyopathy.In this review, we discuss the established role of T2*imaging and rapidly evolving clinical applications of myocardialT2 mapping as quantitative adjuncts to established qualitativeimaging techniques.
Lota AS, Wassall R, Scott AD, et al., 2017, T2 MAPPING IN ACUTE AND RECOVERED MYOCARDITIS: POTENTIAL ROLE IN CLINICAL SURVEILLANCE, 12th Annual Meeting of the British-Society-of-Cardiovascular-Magnetic-Resonance (BSCMR), Publisher: BMJ PUBLISHING GROUP, Pages: A22-A24, ISSN: 1355-6037
Nielles-Vallespin S, Khalique Z, Ferreira PF, et al., 2017, Assessment of myocardial microstructural dynamics by in vivo diffusion tensor cardiac magnetic resonance, Journal of the American College of Cardiology, Vol: 69, Pages: 661-676, ISSN: 0735-1097
BackgroundCardiomyocytes are organized in microstructures termed sheetlets that reorientate during left ventricular thickening. Diffusion tensor cardiac magnetic resonance (DT-CMR) may enable noninvasive interrogation of in vivo cardiac microstructural dynamics. Dilated cardiomyopathy (DCM) is a condition of abnormal myocardium with unknown sheetlet function.ObjectivesThis study sought to validate in vivo DT-CMR measures of cardiac microstructure against histology, characterize microstructural dynamics during left ventricular wall thickening, and apply the technique in hypertrophic cardiomyopathy (HCM) and DCM.MethodsIn vivo DT-CMR was acquired throughout the cardiac cycle in healthy swine, followed by in situ and ex vivo DT-CMR, then validated against histology. In vivo DT-CMR was performed in 19 control subjects, 19 DCM, and 13 HCM patients.ResultsIn swine, a DT-CMR index of sheetlet reorientation (E2A) changed substantially (E2A mobility ∼46°). E2A changes correlated with wall thickness changes (in vivo r2 = 0.75; in situ r2 = 0.89), were consistently observed under all experimental conditions, and accorded closely with histological analyses in both relaxed and contracted states. The potential contribution of cyclical strain effects to in vivo E2A was ∼17%. In healthy human control subjects, E2A increased from diastole (18°) to systole (65°; p < 0.001; E2A mobility = 45°). HCM patients showed significantly greater E2A in diastole than control subjects did (48°; p < 0.001) with impaired E2A mobility (23°; p < 0.001). In DCM, E2A was similar to control subjects in diastole, but systolic values were markedly lower (40°; p < 0.001) with impaired E2A mobility (20°; p < 0.001).ConclusionsMyocardial microstructure dynamics can be characterized by in vivo DT-CMR. Sheetlet function was abnormal in DCM with altered systolic conformation and reduced mobility, contrasting with HCM, which showed reduced mobility with alte
Patel HC, Hayward C, Keegan J, et al., 2017, Effects of renal denervation on vascular remodelling in patients with heart failure and preserved ejection fraction: A randomised control trial, JRSM Cardiovascular Disease, Vol: 6, ISSN: 2048-0040
Objective:To assess the effect of renal denervation (RDT) on micro- and macro-vascular function in patients with heartfailure with preserved ejection fraction (HFpEF).Design:A prospective, randomised, open-controlled trial with blinded end-point analysis.Setting:A single-centre London teaching hospital.Participants:Twenty-five patients with HFpEF who were recruited into the RDT-PEF trial.Main outcome measures:Macro-vascular: 24-h ambulatory pulse pressure, aorta distensibilty (from cardiac magneticresonance imaging (CMR), aorta pulse wave velocity (CMR), augmentation index (peripheral tonometry) and renal arteryblood flow indices (renal MR). Micro-vascular: endothelial function (peripheral tonometry) and urine microalbuminuria.Results:At baseline, 15 patients were normotensive, 9 were hypertensive and 1 was hypotensive. RDT did not lowerany of the blood pressure indices. Though there was evidence of abnormal vascular function at rest, RDT did not affectthese at 3 or 12 months follow-up.Conclusions:RDT did not improve markers of macro- and micro-vascular function.
Captur G, Gatehouse P, Keenan KE, et al., 2016, A medical device-grade T1 and ECV phantom for global T1 mapping quality assurance-the T-1 Mapping and ECV Standardization in cardiovascular magnetic resonance (T1MES) program, JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE, Vol: 18, ISSN: 1097-6647
Vassiliou VS, Heng EL, Gatehouse PD, et al., 2016, Magnetic resonance imaging phantoms for quality-control of myocardial T1 and ECV mapping: specific formulation, long-term stability and variation with heart rate and temperature, Journal of Cardiovascular Magnetic Resonance, Vol: 18, ISSN: 1532-429X
BACKGROUND: Magnetic resonance imaging (MRI) phantoms are routinely used for quality assurance in MRI centres; however their long term stability for verification of myocardial T1/ extracellular volume fraction (ECV) mapping has never been investigated. METHODS: Nickel-chloride agarose gel phantoms were formulated in a reproducible laboratory procedure to mimic blood and myocardial T1 and T2 values, native and late after Gadolinium administration as used in T1/ECV mapping. The phantoms were imaged weekly with an 11 heart beat MOLLI sequence for T1 and long TR spin-echo sequences for T2, in a carefully controlled reproducible manner for 12 months. RESULTS: There were only small relative changes seen in all the native and post gadolinium T1 values (up to 9.0 % maximal relative change in T1 values) or phantom ECV (up to 8.3 % maximal relative change of ECV, up to 2.2 % maximal absolute change in ECV) during this period. All native and post gadolinium T2 values remained stable over time with <2 % change. Temperature sensitivity testing showed MOLLI T1 values in the long T1 phantoms increasing by 23.9 ms per degree increase and short T1 phantoms increasing by 0.3 ms per degree increase. There was a small absolute increase in ECV of 0.069 % (~0.22 % relative increase in ECV) per degree increase. Variation in heart rate testing showed a 0.13 % absolute increase in ECV (~0.45 % relative increase in ECV) per 10 heart rate increase. CONCLUSIONS: These are the first phantoms reported in the literature modeling T1 and T2 values for blood and myocardium specifically for the T1mapping/ECV mapping application, with stability tested rigorously over a 12 month period. This work has significant implications for the utility of such phantoms in improving the accuracy of serial scans for myocardial tissue characterisation by T1 mapping methods and in multicentre work.
Firmin D, 2016, Abstracts, 14th Annual Meeting of the European Association of Cardiovascular Imaging, a registered branch of the ESC, Pages: i1-i80, ISSN: 2047-2404
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