38 results on '"Wissmann, Lukas"'
Search Results
2. A multisample dissolution dynamic nuclear polarization system for serial injections in small animals
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Krajewski, Marcin, Wespi, Patrick, Busch, Julia, Wissmann, Lukas, Kwiatkowski, Grzegorz, Steinhauser, Jonas, Batel, Michael, Ernst, Matthias, and Kozerke, Sebastian
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- 2017
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3. Diffuse myocardial fibrosis precedes subclinical functional myocardial impairment and provides prognostic information in systemic sclerosis.
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Gotschy, Alexander, Jordan, Suzana, Stoeck, Christian T, Deuster, Constantin von, Peer, Tatiana, Gastl, Mareike, Vishnevskiy, Valery, Wissmann, Lukas, Dobrota, Rucsandra, Mihai, Carina, Becker, Mike O, Maurer, Britta, Kozerke, Sebastian, Ruschitzka, Frank, Distler, Oliver, and Manka, Robert
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DISEASE progression ,MYOCARDIUM ,CONFIDENCE intervals ,CARDIOMYOPATHIES ,FUNCTIONAL status ,LEFT ventricular dysfunction ,SYSTEMIC scleroderma ,FIBROSIS ,MAGNETIC resonance imaging ,EARLY diagnosis - Abstract
Aims Myocardial involvement is common in patients with systemic sclerosis (SSc) and causes myocardial fibrosis and subtle ventricular dysfunction. However, the temporal onset of myocardial involvement during the progression of the disease and its prognostic value are yet unknown. We used cardiovascular magnetic resonance (CMR) to investigate subclinical functional impairment and diffuse myocardial fibrosis in patients with very early diagnosis of SSc (VEDOSS) and established SSc and examined whether this was associated with mortality. Methods and results One hundred and ten SSc patients (86 established SSc, 24 VEDOSS) and 15 healthy controls were prospectively recruited. The patients were followed-up for a median duration of 7.0 years (interquartile range 6.0–7.3 years). Study subjects underwent CMR including assessment of myocardial fibrosis [native T1 and extracellular volume (ECV)] and measurement of global longitudinal (GLS) and circumferential (GCS) myocardial strain. Native T1 values and ECV were elevated in VEDOSS and SSc patients compared with controls (P < 0.001). GLS was similar in VEDOSS and controls but significantly impaired in patients with established SSc (P < 0.001). GCS was similar over all groups (P = 0.88). There were 12 deaths during follow-up. Elevated native T1 [hazard ratio (HR) 5.8, 95% confidence interval (CI): 1.7–20.4; P = 0.006] and reduced GLS (HR 6.1, 95% CI: 1.3–29.9; P = 0.038) identified subjects with increased risk of death. Only native T1 was predictive for cardiovascular mortality (P < 0.001). Conclusion Subclinical myocardial involvement first manifests as diffuse myocardial fibrosis identified by the expansion of ECV and increased native T1 in VEDOSS patients while subtle functional impairment only occurs in established SSc. Native T1 and GLS have prognostic value for all-cause mortality in SSc patients. [ABSTRACT FROM AUTHOR]
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- 2023
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4. Hybrid multiband excitation multiecho acquisition for hyperpolarized 13C spectroscopic imaging
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Sigfridsson, Andreas, Weiss, Kilian, Wissmann, Lukas, Busch, Julia, Krajewski, Marcin, Batel, Michael, Batsios, Georgios, Ernst, Matthias, and Kozerke, Sebastian
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- 2015
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5. Iterative k-t principal component analysis with nonrigid motion correction for dynamic three-dimensional cardiac perfusion imaging
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Schmidt, Johannes F. M., Wissmann, Lukas, Manka, Robert, and Kozerke, Sebastian
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- 2014
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6. Multicenter evaluation of dynamic three-dimensional whole-heart myocardial perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve
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Manka Robert, Gebker Rolf, Wissmann Lukas, Jogiya Roy, Motwani Manish, Frick Michael, Reinartz Sebastian D, Schnackenburg Bernhard, Nagel Eike, Plein Sven, and Kozerke Sebastian
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2013
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7. Whole-heart first-pass myocardial perfusion imaging with non-rigid respiratory motion correction
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Schmidt Johannes, Wissmann Lukas, Manka Robert, and Kozerke Sebastian
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2013
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8. Multi-echo single-shot EPI for hyperpolarized 13C cardiac metabolic imaging of small animals
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Sigfridsson Andreas, Weiss Kilian, Wissmann Lukas, Busch Julia, Krajewski Marcin, h-Ici Darach O, Batel Michael, Batsios Georgios, and Kozerke Sebastian
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2013
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9. Divergence-free reconstruction for accelerated 3D phase-contrast flow measurements
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Busch Julia, Giese Daniel, Wissmann Lukas, and Kozerke Sebastian
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2012
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10. Reconstruction of divergence-free velocity fields from cine 3D phase-contrast flow measurements
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Busch, Julia, Giese, Daniel, Wissmann, Lukas, and Kozerke, Sebastian
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- 2013
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11. Whole-heart dynamic three-dimensional magnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: determination of volumetric myocardial ischaemic burden and coronary lesion location
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Manka, Robert, Paetsch, Ingo, Kozerke, Sebastian, Moccetti, Marco, Hoffmann, Rainer, Schroeder, Joerg, Reith, Sebastian, Schnackenburg, Bernhard, Gaemperli, Oliver, Wissmann, Lukas, Wyss, Christophe A., Kaufmann, Philipp A., Corti, Roberto, Boesiger, Peter, Marx, Nikolaus, Lüscher, Thomas F., and Jahnke, Cosima
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- 2012
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12. Hyperpolarized 13C urea myocardial first-pass perfusion imaging using velocity-selective excitation
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Fuetterer, Maximilian, Busch, Julia, Peereboom, Sophie M, von Deuster, Constantin, Wissmann, Lukas, Lipiski, Miriam, Fleischmann, Thea, Cesarovic, Nikola, Stoeck, Christian T, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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lcsh:Diseases of the circulatory (Cardiovascular) system ,Sus scrofa ,Myocardial Infarction ,Contrast Media ,610 Medicine & health ,2705 Cardiology and Cardiovascular Medicine ,170 Ethics ,Myocardial perfusion ,Predictive Value of Tests ,Coronary Circulation ,Dynamic imaging ,13C urea ,2741 Radiology, Nuclear Medicine and Imaging ,Animals ,Urea ,10237 Institute of Biomedical Engineering ,3614 Radiological and Ultrasound Technology ,Carbon Isotopes ,Phantoms, Imaging ,Research ,Myocardial Perfusion Imaging ,Reproducibility of Results ,Magnetic Resonance Imaging ,First-pass perfusion ,Disease Models, Animal ,Hyperpolarization ,lcsh:RC666-701 ,Feasibility Studies ,Female ,Blood Flow Velocity - Abstract
Background A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized 13C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced 1H measurements in-vivo. Methods The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized 13C urea with the velocity-selective vs. conventional excitation, as well as standard 1H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a mid-ventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction. Results Velocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12–20%) for velocity-selective excitation compared to conventional excitation (28–93%), comparable to that of reference 1H gadolinium data (9–15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging. Conclusion The feasibility of hyperpolarized 13C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference 1H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications. Electronic supplementary material The online version of this article (doi:10.1186/s12968-017-0364-4) contains supplementary material, which is available to authorized users.
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- 2017
13. Hyperpolarized C-13 urea myocardial first-pass perfusion imaging using velocity-selective excitation
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Fuetterer, Maximilian, Busch, Julia, Peereboom, Sophie M., Deuster, von Deuster, Constantin, Wissmann, Lukas, Lipiski, Miriam, Fleischmann, Thea, Cesarovic, Nikola, Stoeck, Christian T., and Kozerke, Sebastian
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Myocardial perfusion ,Hyperpolarization ,Dynamic imaging ,C-13 urea ,First-pass perfusion - Abstract
Background A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized 13C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced 1H measurements in-vivo. Methods The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized 13C urea with the velocity-selective vs. conventional excitation, as well as standard 1H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a mid-ventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction. Results Velocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12–20%) for velocity-selective excitation compared to conventional excitation (28–93%), comparable to that of reference 1H gadolinium data (9–15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging. Conclusion The feasibility of hyperpolarized 13C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference 1H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications., Journal of Cardiovascular Magnetic Resonance, 19, ISSN:1097-6647, ISSN:1532-429X
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- 2017
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14. Analysis of spatiotemporal fidelity in quantitative 3D first-pass perfusion cardiovascular magnetic resonance
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Wissmann, Lukas, Gotschy, Alexander, Santelli, Claudio, Tezcan, Kerem Can, Hamada, Sandra, Manka, Robert, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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Medicine(all) ,Whole-heart perfusion ,First-pass myocardial perfusion ,Myocardial blood flow ,Modulation transfer function ,k-t PCA ,k-t SPARSE-SENSE ,3D-MTF ,610 Medicine & health ,2705 Cardiology and Cardiovascular Medicine ,170 Ethics ,10209 Clinic for Cardiology ,2741 Radiology, Nuclear Medicine and Imaging ,10237 Institute of Biomedical Engineering ,ddc:610 ,3614 Radiological and Ultrasound Technology - Abstract
Background Whole-heart first-pass perfusion cardiovascular magnetic resonance (CMR) relies on highly accelerated image acquisition. The influence of undersampling on myocardial blood flow (MBF) quantification has not been systematically investigated yet. In the present work, the effect of spatiotemporal scan acceleration on image reconstruction accuracy and MBF error was studied using a numerical phantom and validated in-vivo. Methods Up to 10-fold scan acceleration using k-t PCA and k-t SPARSE-SENSE was simulated using the MRXCAT CMR numerical phantom framework. Image reconstruction results were compared to ground truth data in the k-f domain by means of modulation transfer function (MTF) analysis. In the x-t domain, errors pertaining to specific features of signal intensity-time curves and MBF values derived using Fermi model deconvolution were analysed. In-vivo first-pass CMR data were acquired in ten healthy volunteers using a dual-sequence approach assessing the arterial input function (AIF) and myocardial enhancement. 10x accelerated 3D k-t PCA and k-t SPARSE-SENSE were compared and related to non-accelerated 2D reference images. Results MTF analysis revealed good recovery of data upon k-t PCA reconstruction at 10x undersampling with some attenuation of higher temporal frequencies. For 10x k-t SPARSE-SENSE the MTF was found to decrease to zero at high spatial frequencies for all temporal frequencies indicating a loss in spatial resolution. Signal intensity-time curve errors were most prominent in AIFs from 10x k-t PCA, thereby emphasizing the need for separate AIF acquisition using a dual-sequence approach. These findings were confirmed by MBF estimation based on AIFs from fully sampled and undersampled simulations. Average in-vivo MBF estimates were in good agreement between both accelerated and the fully sampled methods. Intra-volunteer MBF variation for fully sampled 2D scans was lower compared to 10x k-t PCA and k-t SPARSE-SENSE data. Conclusion Quantification of highly undersampled 3D first-pass perfusion CMR yields accurate MBF estimates provided the AIF is obtained using fully sampled or moderately undersampled scans as part of a dual-sequence approach. However, relative to fully sampled 2D perfusion imaging, intra-volunteer variation is increased using 3D approaches prompting for further developments., Journal of Cardiovascular Magnetic Resonance, 19, ISSN:1097-6647, ISSN:1532-429X
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- 2017
15. First fusion and combined evaluation of 3D-CMR perfusion with 3D-MR coronary angiography
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Gotschy, Alexander, Wissmann, Lukas, Goolaub, Datta Singh, Niemann, Markus, Hamada, Sandra, Kozerke, Sebastian, Manka, Robert, University of Zurich, and Manka, Robert
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170 Ethics ,10042 Clinic for Diagnostic and Interventional Radiology ,10209 Clinic for Cardiology ,610 Medicine & health ,10237 Institute of Biomedical Engineering ,Magnetic resonance angiography ,Magnetic resonance perfusion ,Coronary artery disease ,2705 Cardiology and Cardiovascular Medicine - Published
- 2016
16. Hyperpolarized metabolic MR imaging of acute myocardial changes and recovery after ischemia-reperfusion in a small-animal model
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O h-Ici, Darach, Wespi, Patrick, Busch, Julia, Wissmann, Lukas, Krajewski, Marcin, Weiss, Kilian, Sigfridsson, Andreas, Messroghli, Daniel, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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170 Ethics ,2741 Radiology, Nuclear Medicine and Imaging ,610 Medicine & health ,10237 Institute of Biomedical Engineering - Published
- 2016
17. Quantitative three-dimensional myocardial perfusion cardiovascular magnetic resonance with accurate two-dimensional arterial input function assessment
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Wissmann, Lukas, Niemann, Markus, Gotschy, Alexander, Manka, Robert, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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Medicine(all) ,Arterial input function ,DCE-MRI ,10042 Clinic for Diagnostic and Interventional Radiology ,610 Medicine & health ,2705 Cardiology and Cardiovascular Medicine ,First-pass myocardial perfusion imaging ,Dual-sequence imaging ,170 Ethics ,Myocardial blood flow estimates ,10209 Clinic for Cardiology ,2741 Radiology, Nuclear Medicine and Imaging ,10237 Institute of Biomedical Engineering ,3614 Radiological and Ultrasound Technology - Abstract
Background Quantification of myocardial perfusion from first-pass cardiovascular magnetic resonance (CMR) images at high contrast agent (CA) dose requires separate acquisition of blood pool and myocardial tissue enhancement. In this study, a dual-sequence approach interleaving 2D imaging of the arterial input function with high-resolution 3D imaging for myocardial perfusion assessment is presented and validated for low and high CA dose. Methods A dual-sequence approach interleaving 2D imaging of the aortic root and 3D imaging of the whole left ventricle using highly accelerated k-t PCA was implemented. Rest perfusion imaging was performed in ten healthy volunteers after administration of a Gadolinium-based CA at low (0.025 mmol/kg b.w.) and high dose (0.1 mmol/kg b.w.). Arterial input functions extracted from the 2D and 3D images were analysed for both doses. Myocardial contrast-to-noise ratios (CNR) were compared across volunteers and doses. Variations of myocardial perfusion estimates between volunteers and across myocardial territories were studied. Results High CA dose imaging resulted in strong non-linearity of the arterial input function in the 3D images at peak CA concentration, which was avoided when the input function was derived from the 2D images. Myocardial CNR was significantly increased at high dose compared to low dose, with a 2.6-fold mean CNR gain. Most robust myocardial blood flow estimation was achieved using the arterial input function extracted from the 2D image at high CA dose. In this case, myocardial blood flow estimates varied by 24 % between volunteers and by 20 % between myocardial territories when analysed on a per-volunteer basis. Conclusion Interleaving 2D imaging for arterial input function assessment enables robust quantitative 3D myocardial perfusion imaging at high CA dose., Journal of Cardiovascular Magnetic Resonance, 17, ISSN:1097-6647, ISSN:1532-429X
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- 2015
18. Hybrid multiband excitation multiecho acquisition for hyperpolarized13C spectroscopic imaging
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Sigfridsson, Andreas, Weiss, Kilian, Wissmann, Lukas, Busch, Julia, Krajewski, Marcin, Batel, Michael, Batsios, Georgios, Ernst, Matthias, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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170 Ethics ,2741 Radiology, Nuclear Medicine and Imaging ,610 Medicine & health ,10237 Institute of Biomedical Engineering - Published
- 2015
19. MRXCAT: Realistic numerical phantoms forcardiovascular magnetic resonance
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Wissmann, Lukas, Santelli, Claudio, Segars, William P., and Kozerke, Sebastian
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Image reconstruction ,Cardiovascular magnetic resonance ,XCAT ,Numerical phantom - Abstract
Background Computer simulations are important for validating novel image acquisition and reconstruction strategies. In cardiovascular magnetic resonance (CMR), numerical simulations need to combine anatomical information and the effects of cardiac and/or respiratory motion. To this end, a framework for realistic CMR simulations is proposed and its use for image reconstruction from undersampled data is demonstrated. Methods The extended Cardiac-Torso (XCAT) anatomical phantom framework with various motion options was used as a basis for the numerical phantoms. Different tissue, dynamic contrast and signal models, multiple receiver coils and noise are simulated. Arbitrary trajectories and undersampled acquisition can be selected. The utility of the framework is demonstrated for accelerated cine and first-pass myocardial perfusion imaging using k-t PCA and k-t SPARSE. Results MRXCAT phantoms allow for realistic simulation of CMR including optional cardiac and respiratory motion. Example reconstructions from simulated undersampled k-t parallel imaging demonstrate the feasibility of simulated acquisition and reconstruction using the presented framework. Myocardial blood flow assessment from simulated myocardial perfusion images highlights the suitability of MRXCAT for quantitative post-processing simulation. Conclusion The proposed MRXCAT phantom framework enables versatile and realistic simulations of CMR including breathhold and free-breathing acquisitions., Journal of Cardiovascular Magnetic Resonance, 16, ISSN:1097-6647, ISSN:1532-429X
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- 2014
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20. MRXCAT: Realistic numerical phantoms for cardiovascular magnetic resonance
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Wissmann, Lukas, Santelli, Claudio, Segars, William P, Kozerke, Sebastian, University of Zurich, and Kozerke, Sebastian
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Medicine(all) ,170 Ethics ,2741 Radiology, Nuclear Medicine and Imaging ,610 Medicine & health ,10237 Institute of Biomedical Engineering ,3614 Radiological and Ultrasound Technology ,2705 Cardiology and Cardiovascular Medicine - Published
- 2014
21. Multi-centre study of whole-heart dynamic 3D cardiacmagnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: gender based analysis of diagnostic performance.
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Hamada, Sandra, Gotschy, Alexander, Wissmann, Lukas, Paetsch, Ingo, Jahnke, Cosima, Plein, Sven, Gebker, Rolf, Oebel, Sabrina, Alkadhi, Hatem, Marx, Nikolaus, Lüscher, Thomas F., Kozerke, Sebastian, and Manka, Robert
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CONFIDENCE intervals ,CORONARY disease ,PERFUSION ,RADIONUCLIDE imaging ,RESEARCH funding ,SEX distribution ,THREE-dimensional imaging ,DATA analysis software ,DESCRIPTIVE statistics ,MAGNETIC resonance angiography - Abstract
Aims: Coronary artery disease (CAD) is a leading cause of morbidity and mortality in women and non-invasive testing for CAD in women can be more challenging than in men. This study compared the diagnostic performance of whole-heart dynamic 3D cardiovascular magnetic resonance (CMR) stress perfusion imaging in female and male patients with quantitative coronary angiography (QCA) and fractional flow reserve (FFR) as reference tests. Methods and results: Four hundred sixteen patients with suspected or known CAD were enrolled in five European centres. CMR imaging was performed prior to clinically indicated coronary angiography. QCA was performed in all patients and FFR in 357 of 416 patients. Whole-heart dynamic 3D CMR first-pass perfusion imaging was conducted at rest and during adenosine stress. All CMR analyses were operated by experienced investigators blinded to all clinical data. One hundred nineteen female and 297 male patients were included and successfully examined (mean age 65 ± 11 and 63 ± 11 years, respectively). FFR was performed in 106 female and 251 male patients. Sensitivity and specificity of whole-heart dynamic 3D CMR stress perfusion imaging were 89% (95% CI: 77-96) and 82% (95% CI: 70-90) in the female population and 83% (95% CI: 77-86) and 79% (95% CI: 71-86) in the male population relative to QCA (P = 0.474 and P = 0.83, P-values for comparison between genders). Sensitivity and specificity were 95% (95% CI: 82-99) and 84% (95% CI: 73-92) in the female population and 83% (95% CI: 76-89) and 82% (95% CI: 74-88) in the male population when using FFR as the reference (P = 0.134 and P = 0.936, P-values for comparison between genders). Diagnostic accuracy in females was 92% (95% CI: 85-96) and 86% (95% CI: 81-90) in males when using FFR as the reference. The prevalence of CAD as defined by FFR (<0.8) was 36% in females and 53% in males. Conclusion: Whole-heart dynamic 3D CMR stress perfusion imaging has a high diagnostic accuracy for the detection of significant CAD irrespective of gender and is therefore a suitable non-invasive testing tool to detect myocardial ischaemia in both genders. [ABSTRACT FROM AUTHOR]
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- 2017
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22. Hyperpolarized 13C urea myocardial first-pass perfusion imaging using velocity-selective excitation.
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Fuetterer, Maximilian, Busch, Julia, Peereboom, Sophie M., von Deuster, Constantin, Wissmann, Lukas, Lipiski, Miriam, Fleischmann, Thea, Cesarovic, Nikola, Stoeck, Christian T., and Kozerke, Sebastian
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BIOLOGICAL transport ,ANIMAL experimentation ,BLOOD circulation ,DIAGNOSTIC imaging ,INFARCTION ,MAGNETIC resonance imaging ,RESEARCH methodology ,MYOCARDIUM ,PERFUSION ,IMAGING phantoms ,RADIONUCLIDE imaging ,RESEARCH funding ,SWINE ,TECHNOLOGY ,UREA ,DATA analysis software ,DESCRIPTIVE statistics ,IN vivo studies ,PHYSIOLOGY - Abstract
Background: A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized
13 C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced ¹H measurements in-vivo. Methods: The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized13 C urea with the velocity-selective vs. conventional excitation, as well as standard ¹H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a midventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction. Results: Velocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12-20%) for velocity-selective excitation compared to conventional excitation (28-93%), comparable to that of reference ¹H gadolinium data (9-15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging. Conclusion: The feasibility of hyperpolarized13 C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference ¹H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
23. Multicenter Evaluation of Dynamic Three-Dimensional Magnetic Resonance Myocardial Perfusion Imaging for the Detection of Coronary Artery Disease Defined by Fractional Flow Reserve.
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Manka, Robert, Wissmann, Lukas, Gebker, Rolf, Jogiya, Roy, Motwani, Manish, Frick, Michael, Reinartz, Sebastian, Schnackenburg, Bernhard, Niemann, Markus, Gotschy, Alexander, Kuhl, Christiane, Nagel, Eike, Fleck, Eckart, Marx, Nikolaus, Luescher, Thomas F., Plein, Sven, and Kozerke, Sebastian
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- 2015
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24. Hybrid multiband excitation multiecho acquisition for hyperpolarized 13C spectroscopic imaging.
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Sigfridsson, Andreas, Weiss, Kilian, Wissmann, Lukas, Busch, Julia, Krajewski, Marcin, Batel, Michael, Batsios, Georgios, Ernst, Matthias, and Kozerke, Sebastian
- Abstract
Purpose Fast dynamic imaging of hyperpolarized
13 C-labeled pyruvate and its downstream metabolites shows great potential for probing metabolic changes in the heart. Sequences that allow for fast encoding of the spectral and spatial information of the myocardial metabolism and optimal signal excitation are usually limited by gradient performance, especially at high magnetic fields. Here we propose a combination of a spectral-spatial multiband excitation and multiecho readout to overcome these limitations. Methods By using a low-bandwidth, two-pulse excitation, a thinner slice compared with conventional spectral-spatial excitation is achieved, while at the same time allowing for low flip angle excitation on pyruvate and high flip angle excitation on bicarbonate and lactate, which optimizes signal-to-noise ratio (SNR) in cardiac metabolic imaging. The implementation was evaluated in 13 healthy female Sprague-Dawley rats at 9.4T. Results Using a slice thickness of 4 mm, a mean (± standard deviation) peak SNR of 18.3 (±8.4), 15.2 (±6.6), and 8.6 (±2.0) was observed for pyruvate, lactate, and bicarbonate, respectively. Conclusion This approach provides high SNR in metabolic images while at the same time allowing for a thin slice selection even at high magnetic fields. This is crucial in metabolic imaging in small animal models. Magn Reson Med 73:1713-1717, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]- Published
- 2015
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25. Accelerating hyperpolarized metabolic imaging of the heart by exploiting spatiotemporal correlations.
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Weiss, Kilian, Sigfridsson, Andreas, Wissmann, Lukas, Busch, Julia, Batel, Michael, Krajewski, Marcin, Ernst, Matthias, and Kozerke, Sebastian
- Abstract
Hyperpolarized
13 C-labeled pyruvate is a promising tool to investigate cardiac metabolism. It has been shown that changes in substrate metabolism occur following the induction of ischemia. To investigate the metabolic changes that are confined to spatial regions, high spatiotemporal resolution is required. The present work exploits both spatial and temporal correlations using k-t principal component analysis (PCA) to undersample the spatiotemporal domain, thereby speeding up data acquisition. A numerical model was implemented to investigate optimal acquisition and reconstruction parameters for pyruvate, lactate and bicarbonate maps of the heart. Subsequently, prospectively undersampled in vivo data on rat hearts were acquired using a combination of spectral-spatial signal excitation and a variable-density single-shot echo planar readout. Using five-fold k-t PCA, a spatial resolution of 1 × 1 mm2 at a temporal resolution of 3 s was achieved. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]- Published
- 2013
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26. Hyperpolarized metabolic imaging of myocardial ischemia-reperfusion in a small-animal model at 9.4T
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H-Ici, Darach O., Wespi, Patrick, Busch, Julia, Wissmann, Lukas, Sigfridsson, Andreas, Weiss, Kilian, Messroghli, Daniel, and Kozerke, Sebastian
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Pyruvate ,Swiss National Science Foundation ,Coronary Artery Occlusion ,Pyruvic Acid ,Left Coronary Artery ,3. Good health - Abstract
Journal of Cardiovascular Magnetic Resonance, 17 (S1), ISSN:1097-6647, ISSN:1532-429X
27. A multisample dissolution dynamic nuclear polarization system for serial injections in small animals
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Krajewski, Marcin, Wespi, Patrick, Busch, Julia, Wissmann, Lukas, Kwiatkowski, Grzegorz, Steinhauser, Jonas, Batel, Michael, Ernst, Matthias, and Kozerke, Sebastian
- Subjects
Multi-sample DNP ,Dynamic nuclear polarization ,Metabolic imaging ,Dissolution DNP ,Small animal ,3. Good health - Abstract
Magnetic Resonance in Medicine, 77 (2), ISSN:0740-3194, ISSN:1522-2594
28. Whole-heart dynamic three-dimensional magnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: Determination of volumetric myocardial ischaemic burden and coronary lesion location
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Manka, Robert, Paetsch, Ingo, Kozerke, Sebastian, Moccetti, Marco, Hoffmann, Rainer, Schroeder, Joerg, Reith, Sebastian, Schnackenburg, Bernhard, Gaemperli, Oliver, Wissmann, Lukas, Wyss, Christophe A., Kaufmann, Philipp A., Corti, Roberto, Bösiger, Peter, Marx, Nikolaus, Lüscher, Thomas F., and Jahnke, Cosima
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Three-dimensional cardiac MR perfusion ,Fractional flow reserve ,Adenosine stress ,Cardiac magnetic resonance ,Myocardial ischaemic burden ,3. Good health - Abstract
European Heart Journal, 33 (16), ISSN:1522-9645, ISSN:0195-668X
29. Multicenter evaluation of dynamic threedimensional whole-heart myocardial perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve.
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Manka, Robert, Gebker, Rolf, Wissmann, Lukas, Jogiya, Roy, Motwani, Manish, Frick, Michael, Reinartz, Sebastian D., Schnackenburg, Bernhard, Nagel, Eike, Plein, Sven, and Kozerke, Sebastian
- Subjects
CARDIOVASCULAR disease diagnosis ,CONFERENCES & conventions ,CORONARY circulation ,CORONARY disease ,MAGNETIC resonance imaging ,PERFUSION ,RADIONUCLIDE imaging ,THREE-dimensional imaging - Abstract
An abstract of the article "Multicenter evaluation of dynamic three dimensional whole-heart myocardial perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve," by Robert Manka and colleagues is presented.
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- 2013
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30. Diffuse myocardial fibrosis precedes subclinical functional myocardial impairment and provides prognostic information in systemic sclerosis.
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Gotschy A, Jordan S, Stoeck CT, von Deuster C, Peer T, Gastl M, Vishnevskiy V, Wissmann L, Dobrota R, Mihai C, Becker MO, Maurer B, Kozerke S, Ruschitzka F, Distler O, and Manka R
- Subjects
- Humans, Prognosis, Ventricular Function, Left, Prospective Studies, Myocardium pathology, Fibrosis, Magnetic Resonance Imaging, Cine methods, Predictive Value of Tests, Cardiomyopathies pathology, Scleroderma, Systemic complications, Scleroderma, Systemic diagnostic imaging
- Abstract
Aims: Myocardial involvement is common in patients with systemic sclerosis (SSc) and causes myocardial fibrosis and subtle ventricular dysfunction. However, the temporal onset of myocardial involvement during the progression of the disease and its prognostic value are yet unknown. We used cardiovascular magnetic resonance (CMR) to investigate subclinical functional impairment and diffuse myocardial fibrosis in patients with very early diagnosis of SSc (VEDOSS) and established SSc and examined whether this was associated with mortality., Methods and Results: One hundred and ten SSc patients (86 established SSc, 24 VEDOSS) and 15 healthy controls were prospectively recruited. The patients were followed-up for a median duration of 7.0 years (interquartile range 6.0-7.3 years). Study subjects underwent CMR including assessment of myocardial fibrosis [native T1 and extracellular volume (ECV)] and measurement of global longitudinal (GLS) and circumferential (GCS) myocardial strain. Native T1 values and ECV were elevated in VEDOSS and SSc patients compared with controls (P < 0.001). GLS was similar in VEDOSS and controls but significantly impaired in patients with established SSc (P < 0.001). GCS was similar over all groups (P = 0.88). There were 12 deaths during follow-up. Elevated native T1 [hazard ratio (HR) 5.8, 95% confidence interval (CI): 1.7-20.4; P = 0.006] and reduced GLS (HR 6.1, 95% CI: 1.3-29.9; P = 0.038) identified subjects with increased risk of death. Only native T1 was predictive for cardiovascular mortality (P < 0.001)., Conclusion: Subclinical myocardial involvement first manifests as diffuse myocardial fibrosis identified by the expansion of ECV and increased native T1 in VEDOSS patients while subtle functional impairment only occurs in established SSc. Native T1 and GLS have prognostic value for all-cause mortality in SSc patients., Competing Interests: Conflict of interest: B.M. has/had grant/research support from Abbvie, Protagen, Novartis Biomedical Research, received speaker fees from Böhringer Ingelheim as well as congress support from Pfizer, Roche, Actelion, Mepha, and MSD. C.M. has received congress support from Actelion and Roche, and personal fees from Boehringer-Ingelheim, Mepha, and MEDtalks Switzerland, outside the submitted work. R.D. reports grants/research support from Pfizer, Actelion, and personal fees (speaker/consultancy) from Actelion and Boehringer-Ingelheim, outside the submitted work. O.D. has/had consultancy relationship with and/or has received research funding from or has served as a speaker for the following companies in the area of potential treatments for systemic sclerosis and its complications in the last 3 years: Abbvie, Acceleron, Alcimed, Amgen, AnaMar, Arxx, AstraZeneca, Baecon, Blade, Bayer, Boehringer-Ingelheim, ChemomAb, Corbus, CSL Behring, Galapagos, Glenmark, GSK, Horizon (Curzion), Inventiva, iQvia, Kymera, Lupin, Medac, Medscape, Miltenyi Biotec, Mitsubishi Tanabe, Novartis, Prometheus, Roche, Roivant, Sanofi, Serodapharm, Topadur and UCB. Patent issued ‘mir-29 for the treatment of systemic sclerosis’ (US8247389, EP2331143). O.D. and B.M. have a patent for ‘mir-29 for the treatment of systemic sclerosis’ (US8247389, EP2331143). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2023
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31. Multi-centre study of whole-heart dynamic 3D cardiac magnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: gender based analysis of diagnostic performance.
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Hamada S, Gotschy A, Wissmann L, Paetsch I, Jahnke C, Plein S, Gebker R, Oebel S, Alkadhi H, Marx N, Lüscher TF, Kozerke S, and Manka R
- Subjects
- Adult, Age Factors, Aged, Cohort Studies, Confidence Intervals, Coronary Angiography methods, Coronary Artery Disease physiopathology, Female, Humans, Internationality, Male, Middle Aged, Predictive Value of Tests, ROC Curve, Radiographic Image Enhancement, Retrospective Studies, Sensitivity and Specificity, Severity of Illness Index, Sex Factors, Coronary Artery Disease diagnostic imaging, Fractional Flow Reserve, Myocardial physiology, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging, Cine methods, Myocardial Perfusion Imaging methods
- Abstract
Aims: Coronary artery disease (CAD) is a leading cause of morbidity and mortality in women and non-invasive testing for CAD in women can be more challenging than in men. This study compared the diagnostic performance of whole-heart dynamic 3D cardiovascular magnetic resonance (CMR) stress perfusion imaging in female and male patients with quantitative coronary angiography (QCA) and fractional flow reserve (FFR) as reference tests., Methods and Results: Four hundred sixteen patients with suspected or known CAD were enrolled in five European centres. CMR imaging was performed prior to clinically indicated coronary angiography. QCA was performed in all patients and FFR in 357 of 416 patients. Whole-heart dynamic 3D CMR first-pass perfusion imaging was conducted at rest and during adenosine stress. All CMR analyses were operated by experienced investigators blinded to all clinical data. One hundred nineteen female and 297 male patients were included and successfully examined (mean age 65 ± 11 and 63 ± 11 years, respectively). FFR was performed in 106 female and 251 male patients. Sensitivity and specificity of whole-heart dynamic 3D CMR stress perfusion imaging were 89% (95% CI: 77-96) and 82% (95% CI: 70-90) in the female population and 83% (95% CI: 77-86) and 79% (95% CI: 71-86) in the male population relative to QCA (P = 0.474 and P = 0.83, P-values for comparison between genders). Sensitivity and specificity were 95% (95% CI: 82-99) and 84% (95% CI: 73-92) in the female population and 83% (95% CI: 76-89) and 82% (95% CI: 74-88) in the male population when using FFR as the reference (P = 0.134 and P = 0.936, P-values for comparison between genders). Diagnostic accuracy in females was 92% (95% CI: 85-96) and 86% (95% CI: 81-90) in males when using FFR as the reference. The prevalence of CAD as defined by FFR (<0.8) was 36% in females and 53% in males., Conclusion: Whole-heart dynamic 3D CMR stress perfusion imaging has a high diagnostic accuracy for the detection of significant CAD irrespective of gender and is therefore a suitable non-invasive testing tool to detect myocardial ischaemia in both genders., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2017
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32. Hyperpolarized 13 C urea myocardial first-pass perfusion imaging using velocity-selective excitation.
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Fuetterer M, Busch J, Peereboom SM, von Deuster C, Wissmann L, Lipiski M, Fleischmann T, Cesarovic N, Stoeck CT, and Kozerke S
- Subjects
- Animals, Blood Flow Velocity, Disease Models, Animal, Feasibility Studies, Female, Myocardial Infarction physiopathology, Myocardial Perfusion Imaging instrumentation, Phantoms, Imaging, Predictive Value of Tests, Reproducibility of Results, Sus scrofa, Carbon Isotopes administration & dosage, Contrast Media administration & dosage, Coronary Circulation, Magnetic Resonance Imaging instrumentation, Myocardial Infarction diagnostic imaging, Myocardial Perfusion Imaging methods, Urea administration & dosage
- Abstract
Background: A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized
13 C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced1 H measurements in-vivo., Methods: The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized13 C urea with the velocity-selective vs. conventional excitation, as well as standard1 H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a mid-ventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction., Results: Velocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12-20%) for velocity-selective excitation compared to conventional excitation (28-93%), comparable to that of reference1 H gadolinium data (9-15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging., Conclusion: The feasibility of hyperpolarized13 C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference1 H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications.- Published
- 2017
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33. Analysis of spatiotemporal fidelity in quantitative 3D first-pass perfusion cardiovascular magnetic resonance.
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Wissmann L, Gotschy A, Santelli C, Tezcan KC, Hamada S, Manka R, and Kozerke S
- Subjects
- Adult, Blood Flow Velocity, Feasibility Studies, Fourier Analysis, Healthy Volunteers, Humans, Magnetic Resonance Imaging instrumentation, Models, Cardiovascular, Myocardial Ischemia physiopathology, Myocardial Perfusion Imaging instrumentation, Numerical Analysis, Computer-Assisted, Phantoms, Imaging, Predictive Value of Tests, Reproducibility of Results, Time Factors, Young Adult, Coronary Circulation, Image Interpretation, Computer-Assisted methods, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods, Myocardial Ischemia diagnostic imaging, Myocardial Perfusion Imaging methods
- Abstract
Background: Whole-heart first-pass perfusion cardiovascular magnetic resonance (CMR) relies on highly accelerated image acquisition. The influence of undersampling on myocardial blood flow (MBF) quantification has not been systematically investigated yet. In the present work, the effect of spatiotemporal scan acceleration on image reconstruction accuracy and MBF error was studied using a numerical phantom and validated in-vivo., Methods: Up to 10-fold scan acceleration using k-t PCA and k-t SPARSE-SENSE was simulated using the MRXCAT CMR numerical phantom framework. Image reconstruction results were compared to ground truth data in the k-f domain by means of modulation transfer function (MTF) analysis. In the x-t domain, errors pertaining to specific features of signal intensity-time curves and MBF values derived using Fermi model deconvolution were analysed. In-vivo first-pass CMR data were acquired in ten healthy volunteers using a dual-sequence approach assessing the arterial input function (AIF) and myocardial enhancement. 10x accelerated 3D k-t PCA and k-t SPARSE-SENSE were compared and related to non-accelerated 2D reference images., Results: MTF analysis revealed good recovery of data upon k-t PCA reconstruction at 10x undersampling with some attenuation of higher temporal frequencies. For 10x k-t SPARSE-SENSE the MTF was found to decrease to zero at high spatial frequencies for all temporal frequencies indicating a loss in spatial resolution. Signal intensity-time curve errors were most prominent in AIFs from 10x k-t PCA, thereby emphasizing the need for separate AIF acquisition using a dual-sequence approach. These findings were confirmed by MBF estimation based on AIFs from fully sampled and undersampled simulations. Average in-vivo MBF estimates were in good agreement between both accelerated and the fully sampled methods. Intra-volunteer MBF variation for fully sampled 2D scans was lower compared to 10x k-t PCA and k-t SPARSE-SENSE data., Conclusion: Quantification of highly undersampled 3D first-pass perfusion CMR yields accurate MBF estimates provided the AIF is obtained using fully sampled or moderately undersampled scans as part of a dual-sequence approach. However, relative to fully sampled 2D perfusion imaging, intra-volunteer variation is increased using 3D approaches prompting for further developments.
- Published
- 2017
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34. Hyperpolarized Metabolic MR Imaging of Acute Myocardial Changes and Recovery after Ischemia-Reperfusion in a Small-Animal Model.
- Author
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Oh-Ici D, Wespi P, Busch J, Wissmann L, Krajewski M, Weiss K, Sigfridsson A, Messroghli D, and Kozerke S
- Subjects
- Animals, Biomarkers metabolism, Disease Models, Animal, Electrocardiography, Female, Image Enhancement methods, Image Processing, Computer-Assisted, Rats, Rats, Sprague-Dawley, Reproducibility of Results, Signal-To-Noise Ratio, Magnetic Resonance Imaging, Cine methods, Myocardial Reperfusion Injury diagnosis, Myocardium metabolism
- Abstract
Purpose: To implement hyperpolarized magnetic resonance (MR) imaging in an animal model of ischemia-reperfusion and to assess in vivo the regional changes in pyruvate metabolism within the 1st hour and at 1 week after a brief episode of coronary occlusion and reperfusion., Materials and Methods: All animal experiments were performed with adherence to the Swiss Animal Protection law and were approved by the regional veterinary office. A closed-chest rat model was implemented by using an inflatable balloon secured around the left coronary artery. Animals were placed in an MR system 5-7 days after surgery. [1-(13)C]pyruvate was polarized by using a home-built multisample hyperpolarizer. Hyperpolarized pyruvate was injected at five stages: at baseline; at reperfusion after 15 minutes of coronary occlusion; and at 30 minutes, 60 minutes, and 1 week after ischemia reperfusion. The conversion of pyruvate into lactate and bicarbonate was imaged by using dedicated MR sequences alongside wall motion and delayed enhancement imaging. After imaging, the heart was removed and stained to delineate the area at risk (AAR). Differences between AAR and remote myocardium were assessed by using a repeated measures analysis of variance and a post hoc Bonferroni multiple comparison test., Results: Data were collected in 12 animals. Occlusion led to hypokinesia of the anterior or anterolateral segments of the myocardium. At reperfusion, the average lactate-to-bicarbonate ratio increased in the AAR relative to that at baseline (from 1.93 ± 0.48 to 3.01 ± 0.74, P < .001) and was significantly higher when compared with that in the remote area (1.91 ± 0.38, P < .001). In the 60 minutes after occlusion, the lactate-to-bicarbonate ratio in the AAR recovered but was still elevated relative to that in the remote area. One week after ischemia-reperfusion, no difference between AAR and remote area could be detected., Conclusion: Hyperpolarized metabolic MR imaging can be used to successfully detect acute changes in [1-(13)C]pyruvate metabolism after ischemia-reperfusion, thereby enabling in vivo monitoring of the metabolic effects of reperfusion strategies.
- Published
- 2016
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35. First fusion and combined evaluation of 3D-CMR perfusion with 3D-MR coronary angiography.
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Gotschy A, Wissmann L, Goolaub DS, Niemann M, Hamada S, Kozerke S, and Manka R
- Subjects
- Diagnosis, Differential, Female, Humans, Male, Middle Aged, Reproducibility of Results, Coronary Angiography methods, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging, Cine methods
- Published
- 2016
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36. Quantitative three-dimensional myocardial perfusion cardiovascular magnetic resonance with accurate two-dimensional arterial input function assessment.
- Author
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Wissmann L, Niemann M, Gotschy A, Manka R, and Kozerke S
- Subjects
- Adult, Blood Flow Velocity, Contrast Media administration & dosage, Female, Healthy Volunteers, Humans, Image Interpretation, Computer-Assisted instrumentation, Magnetic Resonance Imaging instrumentation, Male, Models, Cardiovascular, Myocardial Perfusion Imaging instrumentation, Nonlinear Dynamics, Phantoms, Imaging, Predictive Value of Tests, Regional Blood Flow, Young Adult, Coronary Circulation, Coronary Vessels physiology, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging methods, Myocardial Perfusion Imaging methods
- Abstract
Background: Quantification of myocardial perfusion from first-pass cardiovascular magnetic resonance (CMR) images at high contrast agent (CA) dose requires separate acquisition of blood pool and myocardial tissue enhancement. In this study, a dual-sequence approach interleaving 2D imaging of the arterial input function with high-resolution 3D imaging for myocardial perfusion assessment is presented and validated for low and high CA dose., Methods: A dual-sequence approach interleaving 2D imaging of the aortic root and 3D imaging of the whole left ventricle using highly accelerated k-t PCA was implemented. Rest perfusion imaging was performed in ten healthy volunteers after administration of a Gadolinium-based CA at low (0.025 mmol/kg b.w.) and high dose (0.1 mmol/kg b.w.). Arterial input functions extracted from the 2D and 3D images were analysed for both doses. Myocardial contrast-to-noise ratios (CNR) were compared across volunteers and doses. Variations of myocardial perfusion estimates between volunteers and across myocardial territories were studied., Results: High CA dose imaging resulted in strong non-linearity of the arterial input function in the 3D images at peak CA concentration, which was avoided when the input function was derived from the 2D images. Myocardial CNR was significantly increased at high dose compared to low dose, with a 2.6-fold mean CNR gain. Most robust myocardial blood flow estimation was achieved using the arterial input function extracted from the 2D image at high CA dose. In this case, myocardial blood flow estimates varied by 24% between volunteers and by 20% between myocardial territories when analysed on a per-volunteer basis., Conclusion: Interleaving 2D imaging for arterial input function assessment enables robust quantitative 3D myocardial perfusion imaging at high CA dose.
- Published
- 2015
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37. Hybrid multiband excitation multiecho acquisition for hyperpolarized (13) C spectroscopic imaging.
- Author
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Sigfridsson A, Weiss K, Wissmann L, Busch J, Krajewski M, Batel M, Batsios G, Ernst M, and Kozerke S
- Subjects
- Algorithms, Animals, Female, Myocardium pathology, Rats, Rats, Sprague-Dawley, Sensitivity and Specificity, Carbon-13 Magnetic Resonance Spectroscopy methods, Echo-Planar Imaging methods, Energy Metabolism physiology, Image Processing, Computer-Assisted methods, Myocardium metabolism
- Abstract
Purpose: Fast dynamic imaging of hyperpolarized (13) C-labeled pyruvate and its downstream metabolites shows great potential for probing metabolic changes in the heart. Sequences that allow for fast encoding of the spectral and spatial information of the myocardial metabolism and optimal signal excitation are usually limited by gradient performance, especially at high magnetic fields. Here we propose a combination of a spectral-spatial multiband excitation and multiecho readout to overcome these limitations., Methods: By using a low-bandwidth, two-pulse excitation, a thinner slice compared with conventional spectral-spatial excitation is achieved, while at the same time allowing for low flip angle excitation on pyruvate and high flip angle excitation on bicarbonate and lactate, which optimizes signal-to-noise ratio (SNR) in cardiac metabolic imaging. The implementation was evaluated in 13 healthy female Sprague-Dawley rats at 9.4T., Results: Using a slice thickness of 4 mm, a mean (± standard deviation) peak SNR of 18.3 (±8.4), 15.2 (±6.6), and 8.6 (±2.0) was observed for pyruvate, lactate, and bicarbonate, respectively., Conclusion: This approach provides high SNR in metabolic images while at the same time allowing for a thin slice selection even at high magnetic fields. This is crucial in metabolic imaging in small animal models., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2015
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38. MRXCAT: Realistic numerical phantoms for cardiovascular magnetic resonance.
- Author
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Wissmann L, Santelli C, Segars WP, and Kozerke S
- Subjects
- Breath Holding, Coronary Circulation, Feasibility Studies, Heart Rate, Humans, Predictive Value of Tests, Reproducibility of Results, Cardiac-Gated Imaging Techniques instrumentation, Computer Simulation, Magnetic Resonance Imaging, Cine instrumentation, Models, Cardiovascular, Myocardial Perfusion Imaging instrumentation, Numerical Analysis, Computer-Assisted, Phantoms, Imaging, Software Design
- Abstract
Background: Computer simulations are important for validating novel image acquisition and reconstruction strategies. In cardiovascular magnetic resonance (CMR), numerical simulations need to combine anatomical information and the effects of cardiac and/or respiratory motion. To this end, a framework for realistic CMR simulations is proposed and its use for image reconstruction from undersampled data is demonstrated., Methods: The extended Cardiac-Torso (XCAT) anatomical phantom framework with various motion options was used as a basis for the numerical phantoms. Different tissue, dynamic contrast and signal models, multiple receiver coils and noise are simulated. Arbitrary trajectories and undersampled acquisition can be selected. The utility of the framework is demonstrated for accelerated cine and first-pass myocardial perfusion imaging using k-t PCA and k-t SPARSE., Results: MRXCAT phantoms allow for realistic simulation of CMR including optional cardiac and respiratory motion. Example reconstructions from simulated undersampled k-t parallel imaging demonstrate the feasibility of simulated acquisition and reconstruction using the presented framework. Myocardial blood flow assessment from simulated myocardial perfusion images highlights the suitability of MRXCAT for quantitative post-processing simulation., Conclusion: The proposed MRXCAT phantom framework enables versatile and realistic simulations of CMR including breathhold and free-breathing acquisitions.
- Published
- 2014
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