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Dyverfeldt, Petter
Publications (10 of 57) Show all publications
Fredriksson, A. G., Trzebiatowska-Krzynska, A., Dyverfeldt, P., Engvall, J., Ebbers, T. & Carlhäll, C. (2018). Turbulent kinetic energy in the right ventricle: Potential MR marker for risk stratification of adults with repaired Tetralogy of Fallot. Journal of Magnetic Resonance Imaging, 47(4), 1043-1053
Open this publication in new window or tab >>Turbulent kinetic energy in the right ventricle: Potential MR marker for risk stratification of adults with repaired Tetralogy of Fallot
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2018 (English)In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 47, no 4, p. 1043-1053Article in journal (Refereed) Published
Abstract [en]

Purpose: To assess right ventricular (RV) turbulent kinetic energy (TKE) in patients with repaired Tetralogy of Fallot (rToF) and a spectrum of pulmonary regurgitation (PR), as well as to investigate the relationship between these 4D flow markers and RV remodeling.

Materials and Methods: Seventeen patients with rToF and 10 healthy controls were included in the study. Patients were divided into two groups based on PR fraction: one lower PR fraction group (11%) and one higher PR fraction group (>11%). Field strength/sequences: 3D cine phase contrast (4D flow), 2D cine phase contrast (2D flow), and balanced steady-state free precession (bSSFP) at 1.5T. Assessment: The RV volume was segmented in the morphologic short-axis images and TKE parameters were computed inside the segmented RV volume throughout diastole. Statistical tests: One-way analysis of variance with Bonferroni post-hoc test; unpaired t-test; Pearson correlation coefficients; simple and stepwise multiple regression models; intraclass correlation coefficient (ICC).

Results: The higher PR fraction group had more remodeled RVs (140 6 25 vs. 107 6 22 [lower PR fraction, P < 0.01] and 93 6 15 ml/m2[healthy, P < 0.001] for RV end-diastolic volume index [RVEDVI]) and higher TKE values (5.95 6 3.15 vs. 2.23 6 0.81 [lower PR fraction, P < 0.01] and 1.91 6 0.78 mJ [healthy, P < 0.001] for Peak Total RV TKE). Multiple regression analysis between RVEDVI and 4D/2D flow parameters showed that Peak Total RV TKE was the strongest predictor of RVEDVI (R25 0.47, P 5 0.002).

Conclusion: The 4D flow-specific TKE markers showed a slightly stronger association with RV remodeling than conventional 2D flow PR parameters. These results suggest novel hemodynamic aspects of PR in the development of late complications after ToF repair.

Place, publisher, year, edition, pages
Hoboken: John Wiley & Sons, 2018
Keywords
4D flow, MRI, Turbulence, Tetralogy of Fallot, Turbulent kinetic energy
National Category
Radiology, Nuclear Medicine and Medical Imaging Cardiac and Cardiovascular Systems Medical Laboratory and Measurements Technologies Anesthesiology and Intensive Care Medical Image Processing
Identifiers
urn:nbn:se:liu:diva-143780 (URN)10.1002/jmri.25830 (DOI)000427125300016 ()28766919 (PubMedID)2-s2.0-85026745981 (Scopus ID)
Note

Funding agencies:  European Research Council [310612]; Swedish Heart and Lung Foundation [20140398]; County Council of Ostergotland; Medical Research Council of Southeast Sweden (FORSS); Swedish Research Council [2013-6077, 2014-6191]

Available from: 2017-12-18 Created: 2017-12-18 Last updated: 2018-04-12Bibliographically approved
Fredriksson, A. G., Svalbring, E., Eriksson, J., Dyverfeldt, P., Alehagen, U., Engvall, J., . . . Carlhäll, C.-J. (2016). 4D flow MRI can detect subtle right ventricular dysfunction in primary left ventricular disease.. Journal of Magnetic Resonance Imaging, 43(3), 558-565
Open this publication in new window or tab >>4D flow MRI can detect subtle right ventricular dysfunction in primary left ventricular disease.
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2016 (English)In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 43, no 3, p. 558-565Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To investigate whether 4D flow magnetic resonance imaging (MRI) can detect subtle right ventricular (RV) dysfunction in primary left ventricular (LV) disease.

MATERIALS AND METHODS: 4D flow and morphological 3T MRI data were acquired in 22 patients with mild ischemic heart disease who were stratified into two groups based on LV end-diastolic volume index (EDVI): lower-LVEDVI and higher-LVEDVI, as well as in 11 healthy controls. The RV volume was segmented at end-diastole (ED) and end-systole (ES). Pathlines were emitted from the ED volume and traced forwards and backwards in time to ES. The blood volume was separated into flow components. The Direct Flow (DF) component was defined as RV inflow passing directly to outflow. The kinetic energy (KE) of the DF component was calculated. Echocardiographic conventional RV indices were also assessed.

RESULTS: The higher-LVEDVI group had larger LVEDVI and lower LV ejection fraction (98 ± 32 ml/m(2) ; 48 ± 13%) compared to the healthy (67 ± 12, P = 0.002; 64 ± 7, P < 0.001) and lower-LVEDI groups (62 ± 10; 68 ± 7, both P < 0.001). The RV 4D flow-specific measures "DF/EDV volume-ratio" and "DF/EDV KE-ratio at ED" were lower in the higher-LVEDVI group (38 ± 5%; 52 ± 6%) compared to the healthy (44 ± 6; 65 ± 7, P = 0.018 and P < 0.001) and lower-LVEDVI groups (44 ± 6; 64 ± 7, P = 0.011 and P < 0.001). There was no difference in any of the conventional MRI and echocardiographic RV indices between the three groups.

CONCLUSION: We found that in primary LV disease mild impairment of RV function can be detected by 4D flow-specific measures, but not by the conventional MRI and echocardiographic indices. J. Magn. Reson. Imaging 2015.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
4D flow MRI; interventricular interaction; left ventricular disease; right ventricular function
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:liu:diva-124293 (URN)10.1002/jmri.25015 (DOI)000373000300003 ()26213253 (PubMedID)
Note

Funding agencies: Swedish Heart and Lung Foundation; Swedish Research Council; European Union [223615]; Medical Research Council of Southeast Sweden (FORSS); County Council of Ostergotland/Heart and Medicine Center

Available from: 2016-01-25 Created: 2016-01-25 Last updated: 2017-05-03
Casas Garcia, B., Lantz, J., Dyverfeldt, P. & Ebbers, T. (2016). 4D Flow MRI-Based Pressure Loss Estimation in Stenotic Flows: Evaluation Using Numerical Simulations. Magnetic Resonance in Medicine, 75(4), 1808-1821
Open this publication in new window or tab >>4D Flow MRI-Based Pressure Loss Estimation in Stenotic Flows: Evaluation Using Numerical Simulations
2016 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 75, no 4, p. 1808-1821Article in journal (Refereed) Published
Abstract [en]

Purpose: To assess how 4D flow MRI-based pressure and energy loss estimates correspond to net transstenotic pressure gradients (TPG(net)) and their dependence on spatial resolution. Methods: Numerical velocity data of stenotic flow were obtained from computational fluid dynamics (CFD) simulations in geometries with varying stenosis degrees, poststenotic diameters and flow rates. MRI measurements were simulated at different spatial resolutions. The simplified and extended Bernoulli equations, Pressure-Poisson equation (PPE), and integration of turbulent kinetic energy (TKE) and viscous dissipation were compared against the true TPG(net). Results: The simplified Bernoulli equation overestimated the true TPG(net) (8.74 +/- 0.67 versus 6.76 +/- 0.54 mmHg). The extended Bernoulli equation performed better (6.57 +/- 0.53 mmHg), although errors remained at low TPG(net). TPG(net) estimations using the PPE were always close to zero. Total TKE and viscous dissipation correlated strongly with TPG(net) for each geometry (r(2) &gt; 0.93) and moderately considering all geometries (r(2) = 0.756 and r(2) = 0.776, respectively). TKE estimates were accurate and minorly impacted by resolution. Viscous dissipation was overall underestimated and resolution dependent. Conclusion: Several parameters overestimate or are not linearly related to TPG(net) and/or depend on spatial resolution. Considering idealized axisymmetric geometries and in absence of noise, TPG(net) was best estimated using the extended Bernoulli equation. (C) 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2016
Keywords
pressure loss; phase contrast magnetic resonance imaging; aortic valve disease; aortic coarctation
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-127426 (URN)10.1002/mrm.25772 (DOI)000372910900043 ()26016805 (PubMedID)
Note

Funding Agencies|European Research Council [310612]; Swedish Research Council

Available from: 2016-05-01 Created: 2016-04-26 Last updated: 2018-10-10
Petersson, S., Dyverfeldt, P., Sigfridsson, A., Lantz, J., Carlhäll, C. & Ebbers, T. (2016). Quantification of turbulence and velocity in stenotic flow using spiral three-dimensional phase-contrast MRI. Magnetic Resonance in Medicine, 75(3), 1249-1255
Open this publication in new window or tab >>Quantification of turbulence and velocity in stenotic flow using spiral three-dimensional phase-contrast MRI
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2016 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 75, no 3, p. 1249-1255Article in journal (Refereed) Published
Abstract [en]

PurposeEvaluate spiral three-dimensional (3D) phase contrast MRI for the assessment of turbulence and velocity in stenotic flow. MethodsA-stack-of-spirals 3D phase contrast MRI sequence was evaluated in vitro against a conventional Cartesian sequence. Measurements were made in a flow phantom with a 75% stenosis. Both spiral and Cartesian imaging were performed using different scan orientations and flow rates. Volume flow rate, maximum velocity and turbulent kinetic energy (TKE) were computed for both methods. Moreover, the estimated TKE was compared with computational fluid dynamics (CFD) data. ResultsThere was good agreement between the turbulent kinetic energy from the spiral, Cartesian and CFD data. Flow rate and maximum velocity from the spiral data agreed well with Cartesian data. As expected, the short echo time of the spiral sequence resulted in less prominent displacement artifacts compared with the Cartesian sequence. However, both spiral and Cartesian flow rate estimates were sensitive to displacement when the flow was oblique to the encoding directions. ConclusionSpiral 3D phase contrast MRI appears favorable for the assessment of stenotic flow. The spiral sequence was more than three times faster and less sensitive to displacement artifacts when compared with a conventional Cartesian sequence.

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2016
Keywords
phase contrast mri; 4d flow; turbulence mapping; spiral; stenosis
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-126831 (URN)10.1002/mrm.25698 (DOI)000370593700030 ()25846511 (PubMedID)
Note

Funding Agencies|European Research Council [310612]; Swedish Research Council; Swedish e-Science Research Centre

Available from: 2016-04-07 Created: 2016-04-05 Last updated: 2017-05-03
Petersson, S., Sigfridsson, A., Dyverfeldt, P., Carlhäll, C.-J. & Ebbers, T. (2016). Retrospectively Gated Intra-cardiac 4D Flow MRI using Spiral Trajectories. Magnetic Resonance in Medicine, 75(1), 196-206
Open this publication in new window or tab >>Retrospectively Gated Intra-cardiac 4D Flow MRI using Spiral Trajectories
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2016 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 75, no 1, p. 196-206Article in journal (Refereed) Published
Abstract [en]

Background: Four-dimensional (4D) flow MRI is a powerful tool for the quantification of blood flow and enables calculation of a range of unique hemodynamic parameters. However, the application of cardiac 4D flow MRI is limited by long scan times (20-40 minutes). The high efficiency of spiral readouts can be used to reduce scan times without sacrificing SNR. The aim of this work was to develop and validate a retrospectively gated 4D flow MRI sequence using spiral readouts for the measurement of intra-cardiac velocities.

Methods: A retrospectively ECG gated 4D flow sequence using stacks of spiral readouts was implemented on a clinical 1.5 T MRI scanner. The spiral 4D flow MRI sequence was validated in-vivo by comparisons with a two-dimensional (2D) through-plane velocity measurement and a conventional Cartesian 4D flow acquisition (SENSE factor 2) in 7 healthy volunteers (age 27 ± 3 years, four men) and 2 patients (age 19 and 52, women, only spiral 4D flow and 2D). Net volume flow was estimated from all three acquisition approaches and compared using one-way ANOVA. A quantitative pathline based validation was performed on the Cartesian and the spiral 4D flow MRI acquisitions by comparing the left ventricular inflow and outflow (two-tailed paired t-tests).

Results: The scan time of the spiral 4D flow sequence was 44±6% of the Cartesian counterpart. Compared to time-resolved 2D flow in the aorta, the spiral and Cartesian 4D flow acquisitions provided similarly good data, as there was no significant difference between the net volume flow for all acquisitions (Spiral: 89±14 ml, Cartesian: 93±11 ml, 2D: 93±18 ml, p=0.878). There was no significant difference between pathline-based calculations of inflow and outflow with either Cartesian (In: 88±15, Out: 85±16, p = 0.168) or spiral (In: 93±17 ml, Out: 84±18, p = 0.055) 4D flow acquisitions.

Conclusions: Retrospectively gated spiral cardiac 4D flow MRI permits more than two-fold reduction in scan time compared to conventional Cartesian 4D flow MRI without notable loss in data quality. The time-savings offered by spiral trajectories could provide a step towards the expanded clinical use of 4D flow MRI.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-101103 (URN)10.1002/mrm.25612 (DOI)000367739200019 ()
Note

Funding agencies: European Research Council [310612]; Swedish Research Council; Swedish Heart and Lung foundation

Available from: 2013-11-19 Created: 2013-11-19 Last updated: 2017-05-03Bibliographically approved
Dyverfeldt, P., Bissell, M., Barker, A. J., Bolger, A. F., Carlhäll, C., Ebbers, T., . . . Markl, M. (2015). 4D flow cardiovascular magnetic resonance consensus statement. Journal of Cardiovascular Magnetic Resonance, 17(72)
Open this publication in new window or tab >>4D flow cardiovascular magnetic resonance consensus statement
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2015 (English)In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 17, no 72Article, review/survey (Refereed) Published
Abstract [en]

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 1.5x1.5x1.5 - 3x3x3 mm(3), 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.

Place, publisher, year, edition, pages
BioMed Central / Informa Healthcare, 2015
Keywords
4D Flow CMR; 4D Flow MRI; Phase-contrast magnetic resonance imaging; MR flow imaging; Hemodynamics; Flow visualization; Flow quantification; Recommendations; Clinical; Cardiovascular
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-120859 (URN)10.1186/s12968-015-0174-5 (DOI)000359155900001 ()26257141 (PubMedID)
Note

Funding Agencies|Swedish Research Council; Medical Research Council of Southeast Sweden; Linkoping University; British Heart Foundation Centre of Research Excellence; Oxford NIHR Biomedical Research Centre; NIH [K25HL119608]; Swedish Heart and Lung Foundation; European Research Council [HEART4FLOW, 310612]; Radiological Society of North America (RSNA); NIHR Cardiovascular Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust; Imperial College London; National Institutes of Health (NIH) National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) [R01 R01DK096169]; National Institute of Health (NIH) National Heart, Lung, and Blood Institute (NHLBI) [R01HL115828]

Available from: 2015-08-28 Created: 2015-08-28 Last updated: 2017-12-04
Bustamante, M., Petersson, S., Eriksson, J., Alehagen, U., Dyverfeldt, P., Carlhäll, C. & Ebbers, T. (2015). Atlas-based analysis of 4D flow CMR: Automated vessel segmentation and flow quantification. Journal of Cardiovascular Magnetic Resonance, 17(87)
Open this publication in new window or tab >>Atlas-based analysis of 4D flow CMR: Automated vessel segmentation and flow quantification
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2015 (English)In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 17, no 87Article in journal (Refereed) Published
Abstract [en]

Background: Flow volume quantification in the great thoracic vessels is used in the assessment of several cardiovascular diseases. Clinically, it is often based on semi-automatic segmentation of a vessel throughout the cardiac cycle in 2D cine phase-contrast Cardiovascular Magnetic Resonance (CMR) images. Three-dimensional (3D), time-resolved phase-contrast CMR with three-directional velocity encoding (4D flow CMR) permits assessment of net flow volumes and flow patterns retrospectively at any location in a time-resolved 3D volume. However, analysis of these datasets can be demanding. The aim of this study is to develop and evaluate a fully automatic method for segmentation and analysis of 4D flow CMR data of the great thoracic vessels. Methods: The proposed method utilizes atlas-based segmentation to segment the great thoracic vessels in systole, and registration between different time frames of the cardiac cycle in order to segment these vessels over time. Additionally, net flow volumes are calculated automatically at locations of interest. The method was applied on 4D flow CMR datasets obtained from 11 healthy volunteers and 10 patients with heart failure. Evaluation of the method was performed visually, and by comparison of net flow volumes in the ascending aorta obtained automatically (using the proposed method), and semi-automatically. Further evaluation was done by comparison of net flow volumes obtained automatically at different locations in the aorta, pulmonary artery, and caval veins. Results: Visual evaluation of the generated segmentations resulted in good outcomes for all the major vessels in all but one dataset. The comparison between automatically and semi-automatically obtained net flow volumes in the ascending aorta resulted in very high correlation (r(2) = 0.926). Moreover, comparison of the net flow volumes obtained automatically in other vessel locations also produced high correlations where expected: pulmonary trunk vs. proximal ascending aorta (r(2) = 0.955), pulmonary trunk vs. pulmonary branches (r(2) = 0.808), and pulmonary trunk vs. caval veins (r(2) = 0.906). Conclusions: The proposed method allows for automatic analysis of 4D flow CMR data, including vessel segmentation, assessment of flow volumes at locations of interest, and 4D flow visualization. This constitutes an important step towards facilitating the clinical utility of 4D flow CMR.

Place, publisher, year, edition, pages
BIOMED CENTRAL LTD, 2015
Keywords
4D flow cardiovascular magnetic resonance (4D flow CMR); Flow volume; Image segmentation; Image registration; Phase contrast
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-122197 (URN)10.1186/s12968-015-0190-5 (DOI)000362164100002 ()26438074 (PubMedID)
Note

Funding Agencies|Swedish Heart and Lung foundation; Swedish Research Council; European Research Council (HEART4FLOW) [310612]

Available from: 2015-10-26 Created: 2015-10-23 Last updated: 2018-03-22
Sigovan, M., Dyverfeldt, P., Wrenn, J., Tseng, E. E., Saloner, D. & Hope, M. D. (2015). Extended 3D approach for quantification of abnormal ascending aortic flow. Magnetic Resonance Imaging, 33(5), 695-700
Open this publication in new window or tab >>Extended 3D approach for quantification of abnormal ascending aortic flow
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2015 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 33, no 5, p. 695-700Article in journal (Refereed) Published
Abstract [en]

Background: Flow displacement quantifies eccentric flow, a potential risk factor for aneurysms in the ascending aorta, but only at a single anatomic location. The aim of this study is to extend flow displacement analysis to 3D in patients with aortic and aortic valve pathologies. Methods: 43 individuals were studied with 4DFlow MRI in 6 groups: healthy, tricuspid aortic valve (TAV) with aortic stenosis (AS) but no dilatation, TAV with dilatation but no AS, and TAV with both AS and dilatation, BAV without AS or dilatation, BAV without AS but with dilation. The protocol was approved by our institutional review board, and informed consent was obtained. Flow displacement was calculated for multiple planes along the ascending aorta, and 2D and 3D analyses were compared. Results: Good correlation was found between 2D flow displacement and both maximum and average 3D values (r greater than 0.8). Healthy controls had significantly lower flow displacement values with all approaches (p less than 0.05). The highest flow displacement was seen with stenotic TAV and aortic dilation (0.24 +/- 0.02 with maximum flow displacement). The 2D approach underestimated the maximum flow displacement by more than 20% in 13 out of 36 patients (36%). Conclusions: The extended 3D flow displacement analysis offers a more comprehensive quantitative evaluation of abnormal systolic flow in the ascending aorta than 2D analysis. Differences between patient subgroups are better demonstrated, and maximum flow displacement is more reliably assessed.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
MRI; Aorta; Valves; BAV; Eccentric jets
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-119243 (URN)10.1016/j.mri.2015.02.020 (DOI)000354831500024 ()25721998 (PubMedID)
Note

Funding Agencies|Covidien/Radiologic Society of North America Research Scholar Grant; National Institutes of Health [NS059944]; Veterans Affairs Merit Review Grant; Swedish Research Council

Available from: 2015-06-15 Created: 2015-06-12 Last updated: 2017-12-04
Zajac, J., Eriksson, J., Dyverfeldt, P., Bolger, A. F., Ebbers, T. & Carlhäll, C.-J. (2015). Turbulent Kinetic Energy in Normal and Myopathic Left Ventricles. Journal of Magnetic Resonance Imaging, 41(4), 1021-1029
Open this publication in new window or tab >>Turbulent Kinetic Energy in Normal and Myopathic Left Ventricles
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2015 (English)In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 41, no 4, p. 1021-1029Article in journal (Refereed) Published
Abstract [en]

Purpose: To assess turbulent kinetic energy (TKE) within the left ventricle (LV) of healthy subjects using novel 4D flow MRI methods and to compare TKE values to those from a spectrum of patients with dilated cardiomyopathy (DCM).

Methods: 4D flow and morphological MRI-data were acquired in 11 healthy subjects and 9 patients with different degrees of diastolic dysfunction. TKELV was calculated within the LV at each diastolic time frame. At peak early (E) and late (A) diastolic filling, the TKELV was compared to transmitral peak velocity, LV diameter and mitral annular diameter.

Results: In the majority of all subjects, peaks in TKELV could be observed at E and A. Peak TKELV at E was not different between the groups, and correlated with mitral annular dimensions. Peak TKELV at A was higher in DCM patients compared to healthy subjects, and was related to LV diameter and transmitral velocity.

Conclusions: In normal LVs, TKE values are low. Values are highest during early diastole, and diminish with increasing LV size. In a heterogeneous group of DCM patients, late diastolic TKE values are higher than in healthy subjects. Kinetic energy loss due to elevated late diastolic TKE may reflect inefficient flow in dilated LVs.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2015
Keywords
Magnetic resonance imaging, blood flow, turbulent flow, cardiac function, diastolic dysfunction, heart failure
National Category
Medical Engineering Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:liu:diva-99957 (URN)10.1002/jmri.24633 (DOI)000351521700019 ()
Note

Contract grant sponsor: Swedish Heart-Lung Foundation; Contract grant sponsor: Swedish Research Council; Contract grant sponsor: European Research Council.

Available from: 2013-10-24 Created: 2013-10-24 Last updated: 2017-12-06Bibliographically approved
Liu, J., Dyverfeldt, P., Acevedo-Bolton, G., Hope, M. & Saloner, D. (2014). Highly accelerated aortic 4D flow MR imaging with variable-density random undersampling. Magnetic Resonance Imaging, 32(8), 1012-1020
Open this publication in new window or tab >>Highly accelerated aortic 4D flow MR imaging with variable-density random undersampling
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2014 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 32, no 8, p. 1012-1020Article in journal (Refereed) Published
Abstract [en]

Purpose: To investigate an effective time-resolved variable-density random undersampling scheme combined with an efficient parallel image reconstruction method for highly accelerated aortic 4D flow MR imaging with high reconstruction accuracy. Materials and Methods: Variable-density Poisson-disk sampling (vPDS) was applied in both the phase-slice encoding plane and the temporal domain to accelerate the time-resolved 3D Cartesian acquisition of flow imaging. In order to generate an improved initial solution for the iterative self-consistent parallel imaging method (SPIRiT), a sample-selective view sharing reconstruction for time-resolved random undersampling (STIRRUP) was introduced. The performance of different undersampling and image reconstruction schemes were evaluated by retrospectively applying those to fully sampled data sets obtained from three healthy subjects and a flow phantom. Results: Undersampling pattern based on the combination of time-resolved vPDS, the temporal sharing scheme STIRRUP, and parallel imaging SPIRiT, were able to achieve 6-fold accelerated 40 flow MRI with high accuracy using a small number of coils (N = 5). The normalized root mean square error between aorta flow waveforms obtained with the acceleration method and the fully sampled data in three healthy subjects was 0.04 +/- 0.02, and the difference in peak-systolic mean velocity was -0.29 +/- 2.56 cm/s. Conclusion: Qualitative and quantitative evaluation of our preliminary results demonstrate that time-resolved variable-density random sampling is efficient for highly accelerating 40 flow imaging while maintaining image reconstruction accuracy.

Place, publisher, year, edition, pages
Elsevier, 2014
Keywords
Undersampling; Random; Time-resolved; Parallel imaging; Flow; View sharing
National Category
Medical Engineering
Identifiers
urn:nbn:se:liu:diva-110955 (URN)10.1016/j.mri.2014.05.004 (DOI)000341068300006 ()24846341 (PubMedID)
Note

Funding Agencies|NIH [K25 EB014914, R01 NS059944]; VA MERIT Review grant; [VR 621-2013-6077]

Available from: 2014-10-03 Created: 2014-10-01 Last updated: 2017-12-05
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