15 results on '"Kouwenhoven M"'
Search Results
2. High-dose dobutamine stress SSFP cine MRI at 3 Tesla with patient adaptive local RF shimming using dual-source RF transmission
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Berger Alexander, Schnackenburg Bernhard, Schneeweis Christopher, Kelle Sebastian, Klein Christoph, Kouwenhoven Marc, Fleck Eckart, and Gebker Rolf
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2012
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3. Feasibility of high-dose dobutamine stress SSFP cine MRI at 3 Tesla with patient adaptive local RF shimming using dual-source RF transmission: initial results
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Schild Hans H, Gieseke Jürgen, Naehle Claas P, Clauberg Ralf, Kouwenhoven Marc, Müller Andreas, Strach Katharina A, and Thomas Daniel
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2011
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4. Clinical CMR at 3.0 Tesla using parallel RF transmission with patient-adaptive B1 shimming: initial experience
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Schild Hans, Kouwenhoven Marc, Giseke Juergen, Nelles Michael, Naehle Claas, Weisser-Thomas Jutta, Mueller Andreas, and Thomas Daniel
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2010
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5. Automatic segmentation of multi-echo Cardiac Magnetic Resonance images
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Breeuwer Marcel, Kouwenhoven Marc, Zhao Yansong, and Hautvast Gilion
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2009
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6. Sexual quality of life of adolescents and young adult breast cancer survivors.
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Vrancken Peeters NJMC, Vlooswijk C, Bijlsma RM, Kaal SEJ, Kerst JM, Tromp JM, Bos MEMM, van der Hulle T, Lalisang RI, Nuver J, Kouwenhoven MCM, van der Ploeg IMC, van der Graaf WTA, and Husson O
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- Humans, Adolescent, Young Adult, Female, Quality of Life, Survivors, Breast, Breast Neoplasms therapy, Cancer Survivors
- Abstract
Background: With increasing survival rates of adolescents and young adults (AYAs) with breast cancer, health-related quality of life (HRQoL) becomes more important. An important aspect of HRQoL is sexual QoL. This study examined long-term sexual QoL of AYA breast cancer survivors, compared sexual QoL scores with that of other AYA cancer survivors, and identified factors associated with long-term sexual QoL of AYA breast cancer survivors., Materials and Methods: Data of the SURVAYA study were utilized for secondary analyses. Sexual QoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life cancer survivorship core questionnaire (EORTC QLQ-SURV100). Descriptive statistics were used to describe sexual QoL of AYA cancer survivors. Linear regression models were constructed to examine the effect of cancer type on sexual QoL and to identify factors associated with sexual QoL., Results: Of the 4010 AYA cancer survivors, 944 had breast cancer. Mean sexual QoL scores of AYA breast cancer survivors ranged from 34.5 to 60.0 for functional domains and from 25.2 to 41.5 for symptom-orientated domains. AYA breast cancer survivors reported significantly lower sexual QoL compared to AYA survivors of other cancer types on all domains. Age, time since diagnosis, relationship status, educational level, chemotherapy, hormonal therapy, breast surgery, body image, and coping were associated with sexual QoL of AYA breast cancer survivors., Conclusions: AYA breast cancer survivors experience decreased sexual QoL in the long term (5-20 years) after diagnosis and worse score compared to AYA survivors of other cancer types, indicating a clear need to invest in supportive care interventions for those at risk, to enhance sexual well-being., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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7. A qualitative study on the challenges health care professionals face when caring for adolescents and young adults with an uncertain and/or poor cancer prognosis.
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Burgers VWG, van den Bent MJ, Darlington AE, Gualthérie van Weezel AE, Compter A, Tromp JM, Lalisang RI, Kouwenhoven MCM, Dirven L, Harthoorn NCGL, Troost-Heijboer CA, Husson O, and van der Graaf WTA
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- Adolescent, Humans, Prognosis, Uncertainty, Young Adult, Health Personnel psychology, Neoplasms therapy
- Abstract
Background: Adolescents and young adults (AYAs, aged 18-39 years) with advanced cancer have an increased life expectancy due to improvements and refinements in cancer therapies, resulting in a growing group of AYAs living with an uncertain and/or poor cancer prognosis (UPCP). To date, no studies have examined the difficulties of health care professionals (HCPs) providing care to AYAs with a UPCP. This study aimed to understand the challenges in daily clinical practice experienced by HCPs from different disciplines who provide palliative as well as general care to AYAs with a UPCP., Methods: HCPs from a variety of backgrounds (e.g. clinical nurse specialists, medical oncologists, neurologists psychologists) were invited for a semi-structured interview. The interviews were transcribed verbatim and analysed using reflexive thematic analysis. Two AYA patients were actively involved as research partners to increase the relevance of the study design and to optimise interpretation of results., Results: Forty-nine HCPs were interviewed. Overall, we found that the threat of premature death within this young patient group increased emotional impact on HCPs and evoked a feeling of unfairness, which was an extra motivation for HCPs to provide the most optimal care possible. We generated four key themes: (i) emotional confrontation (e.g. feeling helplessness and experiencing a greater sense of empathy), (ii) questioning own professional attitude and skills, (iii) navigating uncertainty (e.g. discussing prognosis and end of life) and (iv) obstacles in the health care organisation (e.g. lack of knowledge and clarity about responsibilities)., Conclusions: HCPs experienced unique emotional and practical challenges when providing care to AYAs with a UPCP. The results from this study highlight the need to develop an education module for HCPs treating AYAs with UPCP to increase their own well-being and optimise the delivery of person- and age-adjusted care., Competing Interests: Disclosure The authors have declared no conflicts of interest., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2022
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8. Clinical Validation of a 3-Dimensional Ultrafast Cardiac Magnetic Resonance Protocol Including Single Breath-Hold 3-Dimensional Sequences.
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Gómez-Talavera S, Fernandez-Jimenez R, Fuster V, Nothnagel ND, Kouwenhoven M, Clemence M, García-Lunar I, Gómez-Rubín MC, Navarro F, Pérez-Asenjo B, Fernández-Friera L, Calero MJ, Orejas M, Cabrera JA, Desco M, Pizarro G, Ibáñez B, and Sánchez-González J
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- Aged, Female, Gadolinium, Humans, Imaging, Three-Dimensional, Magnetic Resonance Spectroscopy, Male, Middle Aged, Predictive Value of Tests, Prospective Studies, Reproducibility of Results, Contrast Media, Magnetic Resonance Imaging, Cine
- Abstract
Objectives: This study sought to clinically validate a novel 3-dimensional (3D) ultrafast cardiac magnetic resonance (CMR) protocol including cine (anatomy and function) and late gadolinium enhancement (LGE), each in a single breath-hold., Background: CMR is the reference tool for cardiac imaging but is time-consuming., Methods: A protocol comprising isotropic 3D cine (Enhanced sensitivity encoding [SENSE] by Static Outer volume Subtraction [ESSOS]) and isotropic 3D LGE sequences was compared with a standard cine+LGE protocol in a prospective study of 107 patients (age 58 ± 11 years; 24% female). Left ventricular (LV) mass, volumes, and LV and right ventricular (RV) ejection fraction (LVEF, RVEF) were assessed by 3D ESSOS and 2D cine CMR. LGE (% LV) was assessed using 3D and 2D sequences., Results: Three-dimensional and LGE acquisitions lasted 24 and 22 s, respectively. Three-dimensional and LGE images were of good quality and allowed quantification in all cases. Mean LVEF by 3D and 2D CMR were 51 ± 12% and 52 ± 12%, respectively, with excellent intermethod agreement (intraclass correlation coefficient [ICC]: 0.96; 95% confidence interval [CI]: 0.94 to 0.97) and insignificant bias. Mean RVEF 3D and 2D CMR were 60.4 ± 5.4% and 59.7 ± 5.2%, respectively, with acceptable intermethod agreement (ICC: 0.73; 95% CI: 0.63 to 0.81) and insignificant bias. Both 2D and 3D LGE showed excellent agreement, and intraobserver and interobserver agreement were excellent for 3D LGE., Conclusions: ESSOS single breath-hold 3D CMR allows accurate assessment of heart anatomy and function. Combining ESSOS with 3D LGE allows complete cardiac examination in <1 min of acquisition time. This protocol expands the indication for CMR, reduces costs, and increases patient comfort., Competing Interests: Funding Support and Author Disclosures Funding included Instituto de Salud Carlos III (ISCIII) and the European Regional Development Fund (ERDF) Grants DTS17/00136 to Dr. Ibáñez and PI19/01704 to Dr. Fernandez-Jimenez; Spanish Society of Cardiology Translational Research Grant 2016 to Dr. Ibáñez; European Research Council ERC-CoG 819775-MATRIX to Dr. Ibáñez; Comunidad de Madrid S2017/BMD-3867-RENIM-CM to Drs. Desco and Ibáñez; and Ministerio de Ciencia e Innovación (MICINN) RETOS2019-107332RB-I00 to Dr. Ibáñez. Dr. Fernandez-Jimenez received funding from the European Union Horizon 2020 research and innovation programme under Marie Skłodowska-Curie Hrant Agreement No. 707642. The CNIC is supported by the ISCIII, the MICINN, and the Pro CNIC Foundation. Drs. Fernandez-Jimenez, Nothnagel, Fuster, Ibáñez, and Javier Sánchez-González are inventors of a joint patent (Philips/CNIC) for the new cine imaging method here described and validated/protected under the IP #2014P00960EP. Drs. Nothnagel, Kouwenhoven, Clemence, and Javier Sánchez-González are Philips employees. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2021
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9. Free-breathing non-contrast-enhanced flow-independent MR angiography using magnetization-prepared 3D non-balanced dual-echo Dixon method: A feasibility study at 3 Tesla.
- Author
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Yoneyama M, Zhang S, Hu HH, Chong LR, Bardo D, Miller JH, Toyonari N, Katahira K, Katsumata Y, Pokorney A, Ng CK, Kouwenhoven M, and Van Cauteren M
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- Adult, Feasibility Studies, Female, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Respiration, Sensitivity and Specificity, Whole Body Imaging methods, Image Enhancement methods, Imaging, Three-Dimensional methods, Magnetic Resonance Angiography methods
- Abstract
In this work we aimed to investigate the feasibility of using a new pulse sequence called Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) for free-breathing non-contrast-enhanced MR angiography (NCE-MRA) for multiple anatomies on 3T. Two magnetization-preparation pulses were incorporated with a three-dimensional dual-echo Dixon sequence. A T2-prep pulse, followed by a non-selective inversion pulse with a short inversion time, together suppressed tissue with short T1 and T2, while enhancing the signal of native blood with long T1 and T2. A two-point non-balanced gradient-echo Dixon method, based on dual-echo acquisition with semi-flexible echo times for water-fat separation, was used for improved fat suppression over a large field of view. General image quality, vasculature visibility, and clinical indications of the proposed method were investigated in healthy subjects and patients in both torso and extremities based on visual inspection. Preliminary results from REACT obtained in free-breathing with no cardiac triggering showed uniform suppression of background tissue over the field of view and robust blood-to-tissue contrast over multiple anatomies. Future clinical studies are warranted for further investigation of its diagnostic performance and limitations., (Copyright © 2019 Elsevier Inc. All rights reserved.)
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- 2019
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10. Selection of magnetization catalyzation and readout methods for modified Look-Locker inversion recovery: a T1 mapping primer.
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Cameron D, Higgins DM, Stehning C, Kouwenhoven M, Bouhrara M, Frenneaux MP, Dawson DK, and Redpath TW
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- Humans, Magnetic Resonance Imaging, Cine instrumentation, Models, Biological, Phantoms, Imaging, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Heart anatomy & histology, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging, Cine methods, Signal Processing, Computer-Assisted
- Abstract
Background: The purpose of this work was to evaluate different magnetization preparation and readout sequences for modified Look-Locker inversion recovery (MOLLI) toward improved T1 mapping in the heart. Elements investigated include: catalyzation sequences to prepare the magnetization before readout, alternate k-space trajectories, a spoiled gradient recalled echo readout, and a 5b(3b)3b MOLLI sampling scheme ('b' denoting beats)., Methods: Conventional 3b(3b)3b(3b)5b MOLLI with a linear k-space trajectory was compared to four variants in simulations, in vitro and in vivo (at 3T). Variants were centric conventional MOLLI, centric-paired conventional MOLLI, linear 5b(3b)3b MOLLI and spoiled gradient recalled echo MOLLI. Each of these was applied with three magnetization catalyzation methods, and T1 measurement accuracy and precision were evaluated in simulations via a Monte Carlo algorithm, in a set of calibrated phantoms, and in ten healthy volunteers. Contrast-to-noise, heart rate dependence and B1+ dependence were also evaluated., Results: A linear k-space trajectory was superior in vitro to centric and centric-paired trajectories. Of the catalyzation methods, preparation of transverse magnetization only-using a linearly increasing flip angle catalyzation-improved MOLLI T1 measurement accuracy, precision, and map quality versus methods that include catalyzation of the longitudinal magnetization. The 5b(3b)3b MOLLI scheme offered comparable native T1 measurement accuracy and precision to conventional MOLLI, despite its shortened acquisition., Conclusions: MOLLI T1 measurement accuracy, precision, and map quality depend on the method of catalyzation of magnetization prior to image acquisition, as well as on the readout method and MOLLI sampling scheme used., (Copyright © 2015 Elsevier Inc. All rights reserved.)
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- 2015
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11. Three-dimensional balanced steady state free precession myocardial perfusion cardiovascular magnetic resonance at 3T using dual-source parallel RF transmission: initial experience.
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Jogiya R, Schuster A, Zaman A, Motwani M, Kouwenhoven M, Nagel E, Kozerke S, and Plein S
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- Adult, Aged, Algorithms, Artifacts, Case-Control Studies, Coronary Artery Disease physiopathology, Feasibility Studies, Female, Humans, Linear Models, Magnetic Resonance Imaging instrumentation, Male, Middle Aged, Myocardial Perfusion Imaging instrumentation, Phantoms, Imaging, Predictive Value of Tests, Principal Component Analysis, Signal-To-Noise Ratio, Time Factors, Young Adult, Coronary Artery Disease diagnosis, Coronary Circulation, Image Interpretation, Computer-Assisted, Imaging, Three-Dimensional, Magnetic Resonance Imaging methods, Myocardial Perfusion Imaging methods
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Background: The purpose of this study was to establish the feasibility of three-dimensional (3D) balanced steady-state-free-precession (bSSFP) myocardial perfusion cardiovascular magnetic resonance (CMR) at 3T using local RF shimming with dual-source RF transmission, and to compare it with spoiled gradient echo (TGRE) acquisition., Methods: Dynamic contrast-enhanced 3D bSSFP perfusion imaging was performed on a 3T MRI scanner equipped with dual-source RF transmission technology. Images were reconstructed using k-space and time broad-use linear acquisition speed-up technique (k-t BLAST) and compartment based principle component analysis (k-t PCA)., Results: In phantoms and volunteers, local RF shimming with dual source RF transmission significantly improved B1 field homogeneity compared with single source transmission (P=0.01). 3D bSSFP showed improved signal-to-noise, contrast-to-noise and signal homogeneity compared with 3D TGRE (29.8 vs 26.9, P=0.045; 23.2 vs 21.6, P=0.049; 14.9% vs 12.4%, p=0.002, respectively). Image quality was similar between bSSFP and TGRE but there were more dark rim artefacts with bSSFP. k-t PCA reconstruction reduced artefacts for both sequences compared with k-t BLAST. In a subset of five patients, both methods correctly identified those with coronary artery disease., Conclusion: Three-dimensional bSSFP myocardial perfusion CMR using local RF shimming with dual source parallel RF transmission at 3T is feasible and improves signal characteristics compared with TGRE. Image artefact remains an important limitation of bSSFP imaging at 3T but can be reduced with k-t PCA.
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- 2014
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12. Evaluation of a subject specific dual-transmit approach for improving B1 field homogeneity in cardiovascular magnetic resonance at 3T.
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Krishnamurthy R, Pednekar A, Kouwenhoven M, Cheong B, and Muthupillai R
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- Adolescent, Adult, Artifacts, Body Mass Index, Body Surface Area, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Prospective Studies, Young Adult, Heart Diseases diagnosis, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging, Cine
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Background: Radiofrequency (RF) shading artifacts degrade image quality while performing cardiovascular magnetic resonance (CMR) at higher field strengths. In this article, we sought to evaluate the effect of local RF (B1 field) shimming by using a dual-source-transmit RF system for cardiac cine imaging and to systematically evaluate the effect of subject body type on the B1 field with and without local RF shimming., Methods: We obtained cardiac images from 37 subjects (including 11 patients) by using dual-transmit 3T CMR. B1 maps with and without subject-specific local RF shimming (exploiting the independent control of transmit amplitude and phase of the 2 RF transmitters) were obtained. Metrics quantifying B1 field homogeneity were calculated and compared with subject body habitus., Results: Local RF shimming across the region encompassed by the heart increased the mean flip angle (μ) in that area (88.5 ± 15.2% vs. 81.2 ± 13.3%; P = 0.0014), reduced the B1 field variation by 42.2 ± 13%, and significantly improved the percentage of voxels closer to μ (39% and 82% more voxels were closer to ± 10% and ± 5% of μ, respectively) when compared with no RF shimming. B1 homogeneity was independent of subject body type (body surface area [BSA], body mass index [BMI] or anterior-posterior/right-left patient width ratio [AP/RL]). Subject specific RF (B1) shimming with a dual-transmit system improved local RF homogeneity across all body types., Conclusion: With or without RF shimming, cardiac B1 field homogeneity does not depend on body type, as characterized by BMI, BSA, and AP/RL. For all body types studied, cardiac B1 field homogeneity was significantly improved by performing local RF shimming with 2 independent RF-transmit channels. This finding indicates the need for subject-specific RF shimming.
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- 2013
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13. Rapid assessment of regional and global left ventricular function using three-dimensional k-t BLAST imaging.
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Huber S, Muthupillai R, Mojibian H, Cheong B, Kouwenhoven M, and Flamm SD
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- Adult, Contrast Media, Female, Humans, Male, Observer Variation, Imaging, Three-Dimensional, Magnetic Resonance Imaging, Cine methods, Ventricular Function, Left
- Abstract
Objective: To test if three-dimensional (3D) cine spatial frequency-temporal frequency Broad-use Linear Acquisition Speed-up Technique (k-t BLAST) is suitable for rapid evaluation of global and regional left ventricular (LV) functional parameters and to evaluate the influence of gadolinium administration., Materials and Methods: Parameters describing global and regional LV function were evaluated in 50 subjects using a two-dimensional (2D) steady-state free precession (SSFP) and pre- and postcontrast 3D k-t BLAST techniques. Data analyses included contrast-to-noise ratio analyses, and statistical evaluations included Bland-Altman, Cohen's kappa and analysis of variance techniques., Results: Bland-Altman analyses revealed that the ejection fraction computed using the 3D k-t BLAST sequences before (bias+/-2S.D., 2.2+/-8.8) and after contrast administration (bias+/-2S.D., 2.7+/-7.6 mol) was comparable to the 2D SSFP technique. Similar agreement was noted for other global LV parameters. The myocardium-to-blood contrast in the apical slices was better in the 3D k-t BLAST sequence after contrast administration than before. Cohen's kappa values demonstrated good agreement between the sequences for evaluating regional wall motion., Conclusions: 3D k-t BLAST can yield global and regional LV functional parameters comparable to those of the 2D SSFP technique in substantially shorter scan times. In 3D k-t BLAST images, myocardium-to-blood contrast in the apical slices is better after contrast administration.
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- 2008
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14. Dealing with the subvoxel vessel position relative to the reconstruction voxel grid in 2D MR quantitative flow measurements.
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Kaandorp DW, Kopinga K, Kouwenhoven M, and Wijn PF
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- Blood Flow Velocity, Computer Simulation, Fourier Analysis, Humans, Male, Phantoms, Imaging, Reproducibility of Results, Aorta anatomy & histology, Aorta physiology, Image Processing, Computer-Assisted, Magnetic Resonance Angiography methods
- Abstract
A method is introduced that quantifies the error in 2D MR Quantitative Flow measurements induced by the position of the vessel relative to the reconstruction voxel grid, called the subvoxel vessel position. In this method, the vessel area and the volume flow rate are determined for all possible subvoxel vessel positions resulting in a mean value with standard deviation. Since the subvoxel vessel position in standard MR image reconstruction is completely arbitrary, the standard deviation can be considered as a measure of its random error contribution. Simulation studies and in vivo measurements show that our method can be used to quantify and subsequently eliminate this random error. It is further quantitatively shown that, for low noise levels, Fourier interpolation to a higher reconstruction matrix also decreases the random error. We conclude that the precision of a 2D MR Quantitative Flow measurement is improved either by using our method or by reconstruction to a higher matrix.
- Published
- 2000
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15. Accuracy and precision of time-averaged flow as measured by nontriggered 2D phase-contrast MR angiography, a phantom evaluation.
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Bakker CJ, Kouwenhoven M, Hartkamp MJ, Hoogeveen RM, and Mali WP
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- Blood Flow Velocity physiology, Humans, Magnetic Resonance Angiography instrumentation, Models, Cardiovascular, Phantoms, Imaging, Reproducibility of Results, Signal Processing, Computer-Assisted, Time Factors, Magnetic Resonance Angiography methods, Pulsatile Flow physiology
- Abstract
The purpose of this study was to assess the accuracy and precision of time-averaged flow as measured by nontriggered 2D PC. Mono-, bi-, and triphasic flow patterns, modelling waveforms encountered in the human vascular system, were generated by a computer-controlled flow system. Time-averaged flow velocity was measured by conventional 2D cardiac-triggered cine PC and by nontriggered 2D PC for different settings of the excitation flip angle and the velocity sensitivity. Accuracy and precision were determined by repeating the measurements (N = 6) and comparing the results against precisely known calibration values. Measurements revealed waveform-specific deviations between triggered and nontriggered acquisitions that depended on the velocity sensitivity and, more strongly, on the flip angle of the nontriggered experiment. This confirmed the theoretically predicted predominance of amplitude over phase effects. Systematic errors could be reduced by decreasing the flip angle and the velocity sensitivity, although at the expense of signal-to-noise, so that additional signal averaging was required to maintain a specified precision. The attainable accuracy appeared to be acceptable only for waveforms with a relatively low pulsatility index. The study demonstrates the feasibility of accurate and precise nontriggered velocity measurements for weakly pulsatile flow and indicates a route towards improving the reliability for highly pulsatile flow.
- Published
- 1995
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