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Sebastian Kozerke

Bio: Sebastian Kozerke is an academic researcher from ETH Zurich. The author has contributed to research in topics: Diffusion MRI & Coronary artery disease. The author has an hindex of 54, co-authored 379 publications receiving 11618 citations. Previous affiliations of Sebastian Kozerke include École Polytechnique Fédérale de Lausanne & King's College London.


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Journal ArticleDOI
TL;DR: A novel pulse sequence scheme is presented that allows the measurement and mapping of myocardial T1 in vivo on a 1.5 Tesla MR system within a single breath‐hold and provides high‐resolution T1 maps of human myocardium in native and post‐contrast situations within asingle breath-hold.
Abstract: A novel pulse sequence scheme is presented that allows the measurement and mapping of myocardial T1 in vivo on a 1.5 Tesla MR system within a single breath-hold. Two major modifications of conventional Look-Locker (LL) imaging are introduced: 1) selective data acquisition, and 2) merging of data from multiple LL experiments into one data set. Each modified LL inversion recovery (MOLLI) study consisted of three successive LL inversion recovery (IR) experiments with different inversion times. We acquired images in late diastole using a single-shot steady-state free-precession (SSFP) technique, combined with sensitivity encoding to achieve a data acquisition window of <200 ms duration. We calculated T1 using signal intensities from regions of interest and pixel by pixel. T1 accuracy at different heart rates derived from simulated ECG signals was tested in phantoms. T1 estimates showed small systematic error for T1 values from 191 to 1196 ms. In vivo T1 mapping was performed in two healthy volunteers and in one patient with acute myocardial infarction before and after administration of Gd-DTPA. T1 values for myocardium and noncardiac structures were in good agreement with values available from the literature. The region of infarction was clearly visualized. MOLLI provides high-resolution T1 maps of human myocardium in native and post-contrast situations within a single breath-hold. Magn Reson Med 52:141–146, 2004. © 2004 Wiley-Liss, Inc.

1,131 citations

Journal ArticleDOI
TL;DR: It is described that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy.
Abstract: Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5×1.5×1.5 – 3×3×3 mm3, typical temporal resolution of 30–40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.

638 citations

Journal ArticleDOI
TL;DR: This review intends to introduce currently used 4D flow MRI methods, including Cartesian and radial data acquisition, approaches for acceleratedData acquisition, cardiac gating, and respiration control, and an overview over the potential this new imaging technique has in different parts of the body from the head to the peripheral arteries.
Abstract: Traditionally, magnetic resonance imaging (MRI) of flow using phase contrast (PC) methods is accomplished using methods that resolve single-directional flow in two spatial dimensions (2D) of an individual slice. More recently, three-dimensional (3D) spatial encoding combined with three-directional velocity-encoded phase contrast MRI (here termed 4D flow MRI) has drawn increased attention. 4D flow MRI offers the ability to measure and to visualize the temporal evolution of complex blood flow patterns within an acquired 3D volume. Various methodological improvements permit the acquisition of 4D flow MRI data encompassing individual vascular structures and entire vascular territories such as the heart, the adjacent aorta, the carotid arteries, abdominal, or peripheral vessels within reasonable scan times. To subsequently analyze the flow data by quantitative means and visualization of complex, three-directional blood flow patterns, various tools have been proposed. This review intends to introduce currently used 4D flow MRI methods, including Cartesian and radial data acquisition, approaches for accelerated data acquisition, cardiac gating, and respiration control. Based on these developments, an overview is provided over the potential this new imaging technique has in different parts of the body from the head to the peripheral arteries.

590 citations

Journal ArticleDOI
TL;DR: Given sufficient data sparsity and base signal‐to‐noise ratio (SNR), CS is demonstrated to result in improved temporal fidelity compared to k‐t BLAST reconstructions for the example data sets used in this work.
Abstract: Recent theoretical advances in the field of compressive sampling-also referred to as compressed sensing (CS)-hold considerable promise for practical applications in MRI, but the fundamental condition of sparsity required in the CS framework is usually not fulfilled in MR images. However, in dynamic imaging, data sparsity can readily be introduced by applying the Fourier transformation along the temporal dimension assuming that only parts of the field-of-view (FOV) change at a high temporal rate while other parts remain stationary or change slowly. The second condition for CS, random sampling, can easily be realized by randomly skipping phase-encoding lines in each dynamic frame. In this work, the feasibility of the CS framework for accelerated dynamic MRI is assessed. Simulated datasets are used to compare the reconstruction results for different reduction factors, noise, and sparsity levels. In vivo cardiac cine data and Fourier-encoded velocity data of the carotid artery are used to test the reconstruction performance relative to k-t broad-use linear acquisition speed-up technique (k-t BLAST) reconstructions. Given sufficient data sparsity and base signal-to-noise ratio (SNR), CS is demonstrated to result in improved temporal fidelity compared to k-t BLAST reconstructions for the example data sets used in this work.

587 citations

Journal ArticleDOI
TL;DR: An optimized sequence protocol for cardiac SSFP imaging at 3.0T is derived, taking into account several partly adverse effects at higher field, such as increased field inhomogeneities, longer T1, and power deposition limitations.
Abstract: Balanced steady-state free precession (SSFP) techniques provide excellent contrast between myocardium and blood at a high signal-to-noise ratio (SNR). Hence, SSFP imaging has become the method of choice for assessing cardiac function at 1.5T. The expected improvement in SNR at higher field strength prompted us to implement SSFP at 3.0T. In this work, an optimized sequence protocol for cardiac SSFP imaging at 3.0T is derived, taking into account several partly adverse effects at higher field, such as increased field inhomogeneities, longer T1, and power deposition limitations. SSFP contrast is established by optimizing the maximum amplitude of the radiofrequency (RF) field strength for shortest TR, as well as by localized linear or second-order shimming and local optimization of the resonance frequency. Given the increased SNR, sensitivity encoding (SENSE) can be employed to shorten breath-hold times. Short-axis, long-axis, and four-chamber cine views obtained in healthy adult subjects are presented, and three different types of artifacts are discussed along with potential methods for reducing them. Magn Reson Med 51:799–806, 2004. © 2004 Wiley-Liss, Inc.

302 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: The If Inhibitor Ivabradine in Patients With Coronary Artery Disease and Left Ventricular Dysfunction is evaluated as well as patients with Diabetes mellitus for Optimal management of Multivessel disease.
Abstract: 99mTc : technetium-99m 201TI : thallium 201 ABCB1 : ATP-binding cassette sub-family B member 1 ABI : ankle-brachial index ACC : American College of Cardiology ACCF : American College of Cardiology Foundation ACCOMPLISH : Avoiding Cardiovascular Events Through Combination Therapy in Patients Living With Systolic Hypertension ACE : angiotensin converting enzyme ACIP : Asymptomatic Cardiac Ischaemia Pilot ACS : acute coronary syndrome ADA : American Diabetes Association ADP : adenosine diphosphate AHA : American Heart Association ARB : angiotensin II receptor antagonist ART : Arterial Revascularization Trial ASCOT : Anglo-Scandinavian Cardiac Outcomes Trial ASSERT : Asymptomatic atrial fibrillation and Stroke Evaluation in pacemaker patients and the atrial fibrillation Reduction atrial pacing Trial AV : atrioventricular BARI 2D : Bypass Angioplasty Revascularization Investigation 2 Diabetes BEAUTIFUL : Morbidity-Mortality Evaluation of the If Inhibitor Ivabradine in Patients With Coronary Artery Disease and Left Ventricular Dysfunction BIMA : bilateral internal mammary artery BMI : body mass index BMS : bare metal stent BNP : B-type natriuretic peptide BP : blood pressure b.p.m. : beats per minute CABG : coronary artery bypass graft CAD : coronary artery disease CAPRIE : Clopidogrel vs. Aspirin in Patients at Risk of Ischaemic Events CASS : Coronary Artery Surgery Study CCB : calcium channel blocker CCS : Canadian Cardiovascular Society CFR : coronary flow reserve CHARISMA : Clopidogrel for High Atherothrombotic Risk and Ischaemic Stabilization, Management and Avoidance CI : confidence interval CKD : chronic kidney disease CKD-EPI : Chronic Kidney Disease Epidemiology Collaboration CMR : cardiac magnetic resonance CORONARY : The CABG Off or On Pump Revascularization Study COURAGE : Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation COX-1 : cyclooxygenase-1 COX-2 : cyclooxygenase-2 CPG : Committee for Practice Guidelines CT : computed tomography CTA : computed tomography angiography CV : cardiovascular CVD : cardiovascular disease CXR : chest X-ray CYP2C19*2 : cytochrome P450 2C19 CYP3A : cytochrome P3A CYP3A4 : cytochrome P450 3A4 CYP450 : cytochrome P450 DANAMI : Danish trial in Acute Myocardial Infarction DAPT : dual antiplatelet therapy DBP : diastolic blood pressure DECOPI : Desobstruction Coronaire en Post-Infarctus DES : drug-eluting stents DHP : dihydropyridine DSE : dobutamine stress echocardiography EACTS : European Association for Cardiothoracic Surgery EECP : enhanced external counterpulsation EMA : European Medicines Agency EASD : European Association for the Study of Diabetes ECG : electrocardiogram Echo : echocardiogram ED : erectile dysfunction EF : ejection fraction ESC : European Society of Cardiology EXCEL : Evaluation of XIENCE PRIME or XIENCE V vs. Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization FAME : Fractional Flow Reserve vs. Angiography for Multivessel Evaluation FDA : Food & Drug Administration (USA) FFR : fractional flow reserve FREEDOM : Design of the Future Revascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease GFR : glomerular filtration rate HbA1c : glycated haemoglobin HDL : high density lipoprotein HDL-C : high density lipoprotein cholesterol HR : hazard ratio HRT : hormone replacement therapy hs-CRP : high-sensitivity C-reactive protein HU : Hounsfield units ICA : invasive coronary angiography IMA : internal mammary artery IONA : Impact Of Nicorandil in Angina ISCHEMIA : International Study of Comparative Health Effectiveness with Medical and Invasive Approaches IVUS : intravascular ultrasound JSAP : Japanese Stable Angina Pectoris KATP : ATP-sensitive potassium channels LAD : left anterior descending LBBB : left bundle branch block LIMA : Left internal mammary artery LDL : low density lipoprotein LDL-C : low density lipoprotein cholesterol LM : left main LMS : left main stem LV : left ventricular LVEF : left ventricular ejection fraction LVH : left ventricular hypertrophy MACE : major adverse cardiac events MASS : Medical, Angioplasty, or Surgery Study MDRD : Modification of Diet in Renal Disease MERLIN : Metabolic Efficiency with Ranolazine for Less Ischaemia in Non-ST-Elevation Acute Coronary Syndromes MERLIN-TIMI 36 : Metabolic Efficiency with Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndromes: Thrombolysis In Myocardial Infarction MET : metabolic equivalents MI : myocardial infarction MICRO-HOPE : Microalbuminuria, cardiovascular and renal sub-study of the Heart Outcomes Prevention Evaluation study MPI : myocardial perfusion imaging MRI : magnetic resonance imaging NO : nitric oxide NSAIDs : non-steroidal anti-inflammatory drugs NSTE-ACS : non-ST-elevation acute coronary syndrome NYHA : New York Heart Association OAT : Occluded Artery Trial OCT : optical coherence tomography OMT : optimal medical therapy PAR-1 : protease activated receptor type 1 PCI : percutaneous coronary intervention PDE5 : phosphodiesterase type 5 PES : paclitaxel-eluting stents PET : positron emission tomography PRECOMBAT : Premier of Randomized Comparison of Bypass Surgery vs. Angioplasty Using Sirolimus-Eluting Stent in Patients with Left Main Coronary Artery Disease PTP : pre-test probability PUFA : polyunsaturated fatty acid PVD : peripheral vascular disease QoL : quality of life RBBB : right bundle branch block REACH : Reduction of Atherothrombosis for Continued Health RITA-2 : Second Randomized Intervention Treatment of Angina ROOBY : Veterans Affairs Randomized On/Off Bypass SAPT : single antiplatelet therapy SBP : systolic blood pressure SCAD : stable coronary artery disease SCORE : Systematic Coronary Risk Evaluation SCS : spinal cord stimulation SES : sirolimus-eluting stents SIMA : single internal mammary artery SPECT : single photon emission computed tomography STICH : Surgical Treatment for Ischaemic Heart Failure SWISSI II : Swiss Interventional Study on Silent Ischaemia Type II SYNTAX : SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery TC : total cholesterol TENS : transcutaneous electrical neural stimulation TERISA : Type 2 Diabetes Evaluation of Ranolazine in Subjects With Chronic Stable Angina TIME : Trial of Invasive vs. Medical therapy TIMI : Thrombolysis In Myocardial Infarction TMR : transmyocardial laser revascularization TOAT : The Open Artery Trial WOEST : What is the Optimal antiplatElet and anticoagulant therapy in patients with oral anticoagulation and coronary StenTing Guidelines summarize and evaluate all evidence available, at the time of the writing process, on a particular issue with the aim of assisting physicians in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well …

3,879 citations

Journal ArticleDOI
TL;DR: The method is based on registering the individual volumes to a model free prediction of what each volume should look like, thereby enabling its use on high b-value data where the contrast is vastly different in different volumes.

2,431 citations

Journal ArticleDOI
TL;DR: The aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI, and provides an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements.

1,333 citations