Publications
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Scott AD, Nielles-Vallespin S, Ferreira PF, et al., 2016, The effects of noise in cardiac diffusion tensor imaging and the benefits of averaging complex data, NMR in Biomedicine, Vol: 29, Pages: 588-599
Yang G, Ye X, Slabaugh G, et al., 2016, Super-Resolved Enhancement of a Single Image and Its Application in Cardiac MRI, Pages: 179-190
Jin N, da Silveira JS, Jolly M-P, et al., 2015, Free-breathing myocardial T2* mapping using GRE-EPI and automatic non-rigid motion correction, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
Alam MH, Auger D, Smith GC, et al., 2015, T1 at 1.5T and 3T compared with conventional T2*at 1.5T for cardiac siderosis, JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE, Vol: 17, ISSN: 1097-6647
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- Citations: 27
Pennell DJ, Baksi AJ, Prasad SK, et al., 2015, Review of Journal of Cardiovascular Magnetic Resonance 2014, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
There were 102 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2014, which is a6 % decrease on the 109 articles published in 2013. The quality of the submissions continues to increase. The 2013JCMR Impact Factor (which is published in June 2014) fell to 4.72 from 5.11 for 2012 (as published in June 2013).The 2013 impact factor means that the JCMR papers that were published in 2011 and 2012 were cited on average4.72 times in 2013. The impact factor undergoes natural variation according to citation rates of papers in the 2 yearsfollowing publication, and is significantly influenced by highly cited papers such as official reports. However,the progress of the journal’s impact over the last 5 years has been impressive. Our acceptance rate is <25 %and has been falling because the number of articles being submitted has been increasing. In accordance withOpen-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articlesinto sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year tosummarize the papers for the readership into broad areas of interest or theme, so that areas of interest canbe reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented inbroad themes and set in context with related literature and previously published JCMR papers to guide continuity ofthought in the journal. We hope that you find the open-access system increases wider reading and citation of yourpapers, and that you will continue to send your quality papers to JCMR for publication.
Giannakidis A, Nyktari E, Keegan J, et al., 2015, Rapid automatic segmentation of abnormal tissue in late gadolinium enhancement cardiovascular magnetic resonance images for improved management of long-standing persistent atrial fibrillation., Biomedical Engineering Online, Vol: 14, ISSN: 1475-925X
BACKGROUND: Atrial fibrillation (AF) is the most common heart rhythm disorder. In order for late Gd enhancement cardiovascular magnetic resonance (LGE CMR) to ameliorate the AF management, the ready availability of the accurate enhancement segmentation is required. However, the computer-aided segmentation of enhancement in LGE CMR of AF is still an open question. Additionally, the number of centres that have reported successful application of LGE CMR to guide clinical AF strategies remains low, while the debate on LGE CMR's diagnostic ability for AF still holds. The aim of this study is to propose a method that reliably distinguishes enhanced (abnormal) from non-enhanced (healthy) tissue within the left atrial wall of (pre-ablation and 3 months post-ablation) LGE CMR data-sets from long-standing persistent AF patients studied at our centre. METHODS: Enhancement segmentation was achieved by employing thresholds benchmarked against the statistics of the whole left atrial blood-pool (LABP). The test-set cross-validation mechanism was applied to determine the input feature representation and algorithm that best predict enhancement threshold levels. RESULTS: Global normalized intensity threshold levels T PRE = 1 1/4 and T POST = 1 5/8 were found to segment enhancement in data-sets acquired pre-ablation and at 3 months post-ablation, respectively. The segmentation results were corroborated by using visual inspection of LGE CMR brightness levels and one endocardial bipolar voltage map. The measured extent of pre-ablation fibrosis fell within the normal range for the specific arrhythmia phenotype. 3D volume renderings of segmented post-ablation enhancement emulated the expected ablation lesion patterns. By comparing our technique with other related approaches that proposed different threshold levels (although they also relied on reference regions from within the LABP) for segmenting enhancement in LGE CMR data-sets of AF patients, we illustra
Giannakidis A, Nyktari E, Keegan J, et al., 2015, Rapid automatic segmentation of abnormal tissue in late gadolinium enhancement cardiovascular magnetic resonance images for improved management of long‑standing persistent atrial fibrillation, Biomedical Engineering Online, Vol: 14, ISSN: 1475-925X
Keegan J, Raphael CE, Parker K, et al., 2015, Validation of high temporal resolution spiral phase velocity mapping of temporal patterns of left and right coronary artery blood flow against Doppler guidewire, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
Background: Temporal patterns of coronary blood flow velocity can provide important information on disease state and are currently assessed invasively using a Doppler guidewire. A non-invasive alternative would be beneficial as it would allow study of a wider patient population and serial scanning. Methods: A retrospectively-gated breath-hold spiral phase velocity mapping sequence (TR 19 ms) was developed at 3 Tesla. Velocity maps were acquired in 8 proximal right and 15 proximal left coronary arteries of 18 subjects who had previously had a Doppler guidewire study at the time of coronary angiography. Cardiovascular magnetic resonance (CMR) velocity-time curves were processed semi-automatically and compared with corresponding invasive Doppler data. Results: When corrected for differences in heart rate between the two studies, CMR mean velocity through the cardiac cycle, peak systolic velocity (PSV) and peak diastolic velocity (PDV) were approximately 40 % of the peak Doppler values with a moderate - good linear relationship between the two techniques (R<sup>2</sup>: 0.57, 0.64 and 0.79 respectively). CMR values of PDV/PSV showed a strong linear relationship with Doppler values with a slope close to unity (0.89 and 0.90 for right and left arteries respectively). In individual vessels, plots of CMR velocities at all cardiac phases against corresponding Doppler velocities showed a consistent linear relationship between the two with high R<sup>2</sup> values (mean +/-SD: 0.79 +/-.13). Conclusions: High temporal resolution breath-hold spiral phase velocity mapping underestimates absolute values of coronary flow velocity but allows accurate assessment of the temporal patterns of blood flow.
Fair MJ, Gatehouse PD, DiBella EVR, et al., 2015, A review of 3D first-pass, whole-heart, myocardial perfusion cardiovascular magnetic resonance, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
A comprehensive review is undertaken of the methods available for 3D whole-heart first-pass perfusion (FPP) andtheir application to date, with particular focus on possible acceleration techniques. Following a summary of theparameters typically desired of 3D FPP methods, the review explains the mechanisms of key accelerationtechniques and their potential use in FPP for attaining 3D acquisitions. The mechanisms include rapid sequences,non-Cartesian k-space trajectories, reduced k-space acquisitions, parallel imaging reconstructions and compressedsensing. An attempt is made to explain, rather than simply state, the varying methods with the hope that it willgive an appreciation of the different components making up a 3D FPP protocol. Basic estimates demonstrating therequired total acceleration factors in typical 3D FPP cases are included, providing context for the extent that eachacceleration method can contribute to the required imaging speed, as well as potential limitations in present 3DFPP literature. Although many 3D FPP methods are too early in development for the type of clinical trials requiredto show any clear benefit over current 2D FPP methods, the review includes the small but growing quantity ofclinical research work already using 3D FPP, alongside the more technical work. Broader challenges concerning FPPsuch as quantitative analysis are not covered, but challenges with particular impact on 3D FPP methods, particularlywith regards to motion effects, are discussed along with anticipated future work in the field.
Fair MJ, Gatehouse PD, Drivas P, et al., 2015, Improved dynamic parallel imaging coil calibration method robust to respiratory motion with application to first-pass contrast-enhanced myocardial perfusion imaging, Magnetic Resonance in Medicine, Vol: 75, Pages: 2315-2323, ISSN: 0740-3194
PURPOSE: To develop an accurate method of performing free-breathing coil calibration for application to parallel imaging reconstructions of dynamic single-shot datasets. METHODS: Coil calibration data are produced through acquisition of multiple prescans before the accelerated scan, applied during free-breathing. These multiple free-breathing prescans (MFPs) provide the necessary coil information for accurate parallel imaging reconstruction of each accelerated frame of a dynamic series, under guidance of an appropriate respiratory position based matching algorithm. This is investigated in myocardial first-pass perfusion with retrospectively undersampled datasets for analysis with standard calibration techniques to guide prospectively undersampled experiments for specific demonstration of performance against a range of "temporal" calibration techniques. RESULTS: Reconstruction of the retrospectively subsampled datasets with MFP-calibrated parallel imaging showed significant improvements in relative root-mean-square error comparative to all other techniques (all P < 0.05; n = 6) for acceleration factors R > 3. Accelerated acquisitions, reconstructed by means of various temporal calibration techniques and analyzed by visual observer artifact scoring, also demonstrated a large improvement with use of MFPs. Artifact levels were reduced from an average of 2.5 ± 0.6 for the best performing implementation of TGRAPPA to 0.8 ± 0.4 for MFP-GRAPPA (P < 0.001; n = 20) (0 = none to 4 = strong, nondiagnostic). CONCLUSION: MFP as parallel imaging coil calibration data can give improved performance in free-breathing dynamic MR while maintaining maximal acceleration. Magn Reson Med 75:2315-2323, 2016. © 2015 Wiley Periodicals, Inc.
Pierce IT, Keegan J, Drivas P, et al., 2015, Free-Breathing 3D Late Gadolinium Enhancement Imaging of the Left Ventricle Using a Stack of Spirals at 3T, Journal of Magnetic Resonance Imaging, Vol: 41, Pages: 1030-1037, ISSN: 1522-2586
Purpose: To develop navigator-gated free-breathing 3Dspiral late gadolinium enhancement (LGE) imaging of theleft ventricle at 3T and compare it with conventionalbreath-hold 2D Cartesian imaging.Materials and Methods: Equivalent slices from 3D spiraland multislice 2D Cartesian acquisitions were comparedin 15 subjects in terms of image quality (1,nondiagnostic to 5, excellent), sharpness (1–3), and presenceof artifacts (0–2). Blood signal-to-noise ratio (SNR),blood/myocardium contrast-to-noise ratio (CNR), andquantitative sharpness were also compared.Results: All 3D spiral scans were completed faster thanan equivalent 2D Cartesian short-axis stack (85 vs. 230 sec,P < 0.001). Image quality was significantly higher for 2DCartesian images than 3D spiral images (3.7 6 0.87 vs.3.4 6 1.05, P ¼ 0.03) but not for mid or apical slices specifi-cally. There were no significant differences in qualitativeand quantitative sharpness (95% confidence interval [CI]:1.91 6 0.67 vs. 1.93 6 0.69, P ¼ 0.83 and 95% CI:0.41 6 0.07 vs. 0.40 6 0.09, P ¼ 0.25, respectively), artifactscores (95% CI: 0.16 6 0.37 vs. 0.40 6 0.58, P ¼ 0.16), SNR(95% CI: 121.5 6 55.3 vs. 136.4 6 77.9, P ¼ 0.13), and CNR(95% CI: 101.6 6 48.4 vs. 102.7 6 61.8, P ¼ 0.98). Similarenhancement ratios (0.65 vs. 0.62) and volumes (13.8 vs.14.1cm3) were measured from scar regions of three patients.Conclusio: Navigator-gated 3D spiral LGE imaging canbe performed in significantly and substantially shorteracquisition durations, although with some reduced imagequality, than multiple breath-hold 2D Cartesian imagingwhile providing higher resolution and contiguous coverage.
Keegan J, Patel HC, Simpson RM, et al., 2015, Inter-study reproducibility of interleaved spiral phase velocity mapping of renal artery haemodynamics, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
Vassiliou V, Heng EL, Donovan J, et al., 2015, Longitudinal stability of gel T1 MRI Phantoms for quality assurance of T1 mapping, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
Scott AD, Nielles-Vallespin S, Ferreira P, et al., 2015, Improving the accuracy of cardiac DTI by averaging the complex data, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647
McGill LA, Scott AD, Ferreira P, et al., 2015, Heterogeneity of diffusion tensor imaging measurements of fractional anisotropy and mean diffusivity in normal human hearts in vivo, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1097-6647
Keegan J, Patel H, Simpson R, et al., 2015, Inter-study reproducibility of interleaved spiral phase velocity mapping of renal artery haemodynamics, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647
Fair M, Gatehouse P, Firmin D, 2015, Through-plane dark-rim artefacts in 3D first-pass myocardial perfusion, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1532-429X
The dark-rim artefact (DRA) is well known in 2D first-pass perfusion (FPP). The in-plane features of DRA are understood, but DRA has not been examined along the second phase-encoding (partition) direction for 3D FPP. The Gibbs contribution to DRAs in 2D FPP is minimised by finer resolution, but low through-plane resolutions of 3D FPP imply risk of partition axis DRAs. We investigated these new partition DRAs ("PDRAs") and partial volume effects due to coarse resolution of this direction.
Giannakidis A, Ferreira P, Gullberg GT, et al., 2015, Transmural gradients of preferential diffusion motility in the normal rat myocardium characterized by diffusion tensor imaging, Journal of Cardiovascular Magnetic Resonance, Vol: 17, Pages: 1-3, ISSN: 1097-6647
Scott AD, Ferreira P, Nielles-Vallespin S, et al., 2015, Directions vs. averages: An in-vivo comparison for cardiac DTI, Journal of Cardiovascular Magnetic Resonance, Pages: 1-2, ISSN: 1097-6647
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Keegan J, Raphael CE, Simpson R, et al., 2015, Validation of high temporal resolution spiral phase velocity mapping of coronary artery blood flow against Doppler flow wire, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647
Vassiliou V, Heng EL, Nyktari E, et al., 2015, Effect of temperature and heart rate variability on Phantom T1 maps, Journal of Cardiovascular Magnetic Resonance, Pages: 1-2, ISSN: 1097-6647
Kilner PJ, McCarthy K, Murillo M, et al., 2015, Histology of human myocardial laminar microstructure and consideration of its cyclic deformations with respect to interpretation of in vivo cardiac diffusion tensor imaging, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647
Keegan J, Gatehouse PD, Haldar S, et al., 2015, Dynamic Inversion Time for Improved 3D Late Gadolinium Enhancement Imaging in Patients with Atrial Fibrillation, Magnetic Resonance in Medicine, Vol: 73, Pages: 646-654, ISSN: 1522-2594
Purpose—High resolution 3D late gadolinium enhancement (LGE) imaging is performed withsingle R-wave gating to minimise lengthy acquisition durations. In patients with atrial fibrillation(AF), heart rate variability results in variable magnetisation recovery between sequence repeatsand image quality is often poor. In this study, we implemented and tested a dynamic inversiontime scheme designed to reduce sequence sensitivity to heart rate variations.Methods—An inversion-prepared 3D segmented gradient echo sequence was modified so thatthe inversion time (TI) varied automatically from beat-to-beat (dynamic-TI) based on the timesince the last sequence repeat. 3D LGE acquisitions were performed in 17 patients prior to RFablation of persistent AF both with and without dynamic-TI. Qualitative image quality scores,blood signal-to-ghosting ratios (SGRs) and blood-myocardium contrast-to-ghosting ratios (CGRs)were compared.Results—Image quality scores were higher with dynamic-TI than without (2.2 +/− 0.9 versus 1.8+/− 1.1, p = 0.008) as were blood-myocardium CGRs (13.8 +/− 7.6 versus 8.3 +/− 6.1, p = 0.003)and blood SGRs (19.6 +/− 8.5 versus 13.1 +/− 8.0, p = 0.003).Conclusions—The dynamic-TI algorithm improves image quality of 3D LGE imaging in thisdifficult patient population by reducing the sequence sensitivity to RR interval variations.
Ferreira PF, Firmin DN, 2015, Imaging artifacts, Basic Principles of Cardiovascular MRI: Physics and Imaging Technique, Pages: 97-133, ISBN: 9783319221403
Cardiovascular MR offers a large range of applications. Many of these are still currently under active development by the research community, for improved accuracy and reliability. The complex nature of the cardiovascular system offers many challenges to clinicians. Its unique mixture of respiratory and cardiac motion; fast fl owing blood; and the tissue-air interface between the heart and the lungs, are just some of the diffi culties faced. Many of these challenges can result in imaging artifacts and measurement errors, which may limit the diagnostic potential of the scan or even contribute to misinterpretation. A good understanding of the physical principles behind the formation of such artifacts is imperative to identifying and minimising them. This chapter summarises, in a language accessible for a clinical readership, the most problematic artifacts specifi c to cardiovascular MR, with particular regard to their physical basis, and implications for the different sequences and applications. It includes motion (respiratory, cardiac and blood fl ow); Gibbs ringing; aliasing; chemical-shift; and B 0 -inhomogeneities.
Strain S, Keegan J, Raphael CE, et al., 2015, Abstracts of the 2015 SCMR/EuroCMR Joint Scientific Sessions, February 4-7, 2015, Nice, France., J Cardiovasc Magn Reson, Vol: 17 Suppl 1, Pages: M1-W36
Koutsoumpa C, Simpson R, Keegan J, et al., 2015, Restoration of Phase-Contrast Cardiovascular MRI for the Construction of Cardiac Contractility Atlases, 5th International Workshop, (STACOM), Publisher: SPRINGER-VERLAG BERLIN, Pages: 275-283, ISSN: 0302-9743
Scott AD, Ferreira PFADC, Nielles-Vallespin S, et al., 2015, Optimal diffusion weighting for in vivo cardiac diffusion tensor imaging, Magnetic resonance in medicine, Vol: 74, Pages: 420-430
McGill L-A, Scott AD, Ferreira PF, et al., 2015, Heterogeneity of fractional anisotropy and mean diffusivity measurements by in vivo diffusion tensor imaging in normal human hearts, PloS one, Vol: 10, Pages: e0132360-e0132360
Donya M, Radford M, ElGuindy A, et al., 2014, Radiation in medicine: Origins, risks and aspirations., Global Cardiology Science and Practice, Vol: 2014, Pages: 437-448, ISSN: 2305-7823
The use of radiation in medicine is now pervasive and routine. From their crude beginnings 100 years ago, diagnostic radiology, nuclear medicine and radiation therapy have all evolved into advanced techniques, and are regarded as essential tools across all branches and specialties of medicine. The inherent properties of ionizing radiation provide many benefits, but can also cause potential harm. Its use within medical practice thus involves an informed judgment regarding the risk/benefit ratio. This judgment requires not only medical knowledge, but also an understanding of radiation itself. This work provides a global perspective on radiation risks, exposure and mitigation strategies.
Pennell DJ, Baksi AJ, Kilner PJ, et al., 2014, Review of Journal of Cardiovascular Magnetic Resonance 2013, Journal of Cardiovascular Magnetic Resonance, Vol: 16, ISSN: 1532-429X
There were 109 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2013, which is a21% increase on the 90 articles published in 2012. The quality of the submissions continues to increase. The editorsare delighted to report that the 2012 JCMR Impact Factor (which is published in June 2013) has risen to 5.11, upfrom 4.44 for 2011 (as published in June 2012), a 15% increase and taking us through the 5 threshold for the firsttime. The 2012 impact factor means that the JCMR papers that were published in 2010 and 2011 were cited onaverage 5.11 times in 2012. The impact factor undergoes natural variation according to citation rates of papers inthe 2 years following publication, and is significantly influenced by highly cited papers such as official reports.However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is<25% and has been falling because the number of articles being submitted has been increasing. In accordancewith Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articlesinto sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendaryear to summarize the papers for the readership into broad areas of interest or theme, so that areas of interestcan be reviewed in a single article in relation to each other and other recent JCMR articles. The papers arepresented in broad themes and set in context with related literature and previously published JCMR papers toguide continuity of thought in the journal. We hope that you find the open-access system increases widerreading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR forpublication.
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