101
|
AMANO Y, SEKINE T, SUZUKI Y, TANAKA K, TAKAGI R, KUMITA S. Time-resolved Three-dimensional Magnetic Resonance Velocity Mapping of Chronic Thoracic Aortic Dissection: A Preliminary Investigation. Magn Reson Med Sci 2011; 10:93-9. [DOI: 10.2463/mrms.10.93] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
102
|
François CJ, Lum DP, Johnson KM, Landgraf BR, Bley TA, Reeder SB, Schiebler ML, Grist TM, Wieben O. Renal arteries: isotropic, high-spatial-resolution, unenhanced MR angiography with three-dimensional radial phase contrast. Radiology 2010; 258:254-60. [PMID: 20980449 DOI: 10.1148/radiol.10100443] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE To prospectively compare a new three-dimensional (3D) radial phase-contrast magnetic resonance (MR) angiographic method with contrast material-enhanced MR angiography for anatomic assessment of the renal arteries. MATERIALS AND METHODS An institutional review board approved this prospective HIPAA-compliant study. Informed consent was obtained. Twenty-seven subjects (mean age, 52.6 years ± 20.5 [standard deviation]) were imaged with respiratory-gated phase-contrast vastly undersampled isotropic projection reconstruction (VIPR) prior to contrast-enhanced MR angiographic acquisition with a 3.0-T clinical system. The imaging duration for phase-contrast VIPR was 10 minutes and provided magnitude and complex difference ("angiographic") images with 3D volumetric (320 mm) coverage and isotropic high spatial resolution (1.25 mm(3)). Quantitative analysis consisted of comparing vessel diameters between the two techniques. Qualitative assessment included evaluation of the phase-contrast VIPR and contrast-enhanced MR angiographic techniques for artifacts, noise, and image quality. Bland-Altman analysis was used for comparison of quantitative measurements, and the Wilcoxon signed rank test was used for comparison of qualitative scores. RESULTS Phase-contrast VIPR images were successfully acquired in all subjects. The vessel diameters measured with phase-contrast VIPR were slightly greater than those measured with contrast-enhanced MR angiography (mean bias = 0.09 mm). Differences in mean artifact, quality scores for the proximal renal arteries, and overall image quality scores between phase-contrast VIPR and contrast-enhanced MR angiographic techniques were not statistically significant (P = .31 and .29, .27 and .39, and .43 and .69 for readers 1 and 2, respectively). The quality scores for the segmental renal arteries were higher for phase-contrast VIPR than for contrast-enhanced MR angiography (P < .05). Although the noise scores were higher with phase-contrast VIPR than with contrast-enhanced MR angiography and were statistically significant (P < .05), the presence of noise did not interfere with the ability to interpret the images. CONCLUSION Isotropic, high-spatial-resolution, unenhanced MR angiography of the renal arteries is feasible with 3D radial undersampling.
Collapse
Affiliation(s)
- Christopher J François
- Department of Radiology, Cardiothoracic and MRI Divisions, University of Wisconsin, 600 Highland Ave, Madison, WI 53792-3252, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
103
|
Modak RK, Koullias GJ, Govindarajulu US, Tranquilli M, Barash PG, Elefteriades JA. Ascending Aortic Aneurysms: Asymmetrical Differences in Aortic Cross-Sectional Wall Motion Detected by Epiaortic Echocardiography. J Cardiothorac Vasc Anesth 2010; 24:776-9. [DOI: 10.1053/j.jvca.2010.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Indexed: 11/11/2022]
|
104
|
Voges I, Jerosch-Herold M, Hedderich J, Westphal C, Hart C, Helle M, Scheewe J, Pardun E, Kramer HH, Rickers C. Maladaptive aortic properties in children after palliation of hypoplastic left heart syndrome assessed by cardiovascular magnetic resonance imaging. Circulation 2010; 122:1068-76. [PMID: 20805434 DOI: 10.1161/circulationaha.109.889733] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The status of the reconstructed aorta in hypoplastic left heart syndrome is considered an important determinant of long-term prognosis. Therefore, we assessed the anatomy, elastic properties, and viability of the aorta and right ventricular function in patients with hypoplastic left heart syndrome by cardiovascular magnetic resonance imaging. METHODS AND RESULTS Cardiovascular magnetic resonance imaging was performed in 40 patients with hypoplastic left heart syndrome (age, 6.0±2.2 years) and 13 control subjects (age, 6.6±2.2 years). Aortic dimensions and distensibility were calculated at different locations of the aorta using gradient-echo cine imaging at 3.0 T. Additionally, pulse-wave velocity, right ventricular ejection fraction, and aortic late gadolinium enhancement for viability assessment were measured. Compared with control subjects, patients with hypoplastic left heart syndrome had increased axial diameters of the aortic root (36.0±5.5 versus 24.1±2.7 mm/m(2); P<0.01), ascending aorta (32.0±5.0 versus 21.3±1.5 mm/m(2); P<0.01), and transverse aortic arch (22.7±5.2 versus 18.7±2.5 mm/m(2); P<0.01). Wall distensibility was reduced in the ascending aorta (4.1±2.4 versus 13.5±7.2 10(-3) mm Hg(-1); P<0.01) and transverse aortic arch (5.4±3.6 versus 10.3±3.5 10(-3) mm Hg(-1); P<0.01). Pulse-wave velocity trended higher in patients (P=0.06). Reduced distensibility in the ascending aorta correlated with the amount of late gadolinium enhancement in a volume that included the aortic root and the ascending aorta (r=-0.72, P<0.01), and both parameters correlated with decreased right ventricular ejection fraction. CONCLUSIONS Adverse aortic properties post palliation of hypoplastic left heart syndrome manifest themselves by aortic dilatation, decreased distensibility, and increased volume of nonviable aortic wall tissue. The negative association between aortic late gadolinium enhancement and right ventricular ejection fraction suggests unfavorable aortic-ventricular coupling. The potential impact of these findings on long-term right ventricular function should be evaluated in future studies.
Collapse
Affiliation(s)
- Inga Voges
- Department of Congenital Heart Disease and Pediatric Cardiology, University Hospital of Schleswig-Holstein, Kiel, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
105
|
Morbiducci U, Ponzini R, Rizzo G, Cadioli M, Esposito A, Montevecchi FM, Redaelli A. Mechanistic insight into the physiological relevance of helical blood flow in the human aorta: an in vivo study. Biomech Model Mechanobiol 2010; 10:339-55. [PMID: 20652615 DOI: 10.1007/s10237-010-0238-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
Abstract
The hemodynamics within the aorta of five healthy humans were investigated to gain insight into the complex helical flow patterns that arise from the existence of asymmetries in the aortic region. The adopted approach is aimed at (1) overcoming the relative paucity of quantitative data regarding helical blood flow dynamics in the human aorta and (2) identifying common characteristics in physiological aortic flow topology, in terms of its helical content. Four-dimensional phase-contrast magnetic resonance imaging (4D PC MRI) was combined with algorithms for the calculation of advanced fluid dynamics in this study. These algorithms allowed us to obtain a 4D representation of intra-aortic flow fields and to quantify the aortic helical flow. For our purposes, helicity was used as a measure of the alignment of the velocity and the vorticity. There were two key findings of our study: (1) intra-individual analysis revealed a statistically significant difference in the helical content at different phases of systole and (2) group analysis suggested that aortic helical blood flow dynamics is an emerging behavior that is common to normal individuals. Our results also suggest that helical flow might be caused by natural optimization of fluid transport processes in the cardiovascular system, aimed at obtaining efficient perfusion. The approach here applied to assess in vivo helical blood flow could be the starting point to elucidate the role played by helicity in the generation and decay of rotating flows in the thoracic aorta.
Collapse
Affiliation(s)
- Umberto Morbiducci
- Department of Mechanics, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy.
| | | | | | | | | | | | | |
Collapse
|
106
|
Hope MD, Meadows AK, Hope TA, Ordovas KG, Saloner D, Reddy GP, Alley MT, Higgins CB. Clinical evaluation of aortic coarctation with 4D flow MR imaging. J Magn Reson Imaging 2010; 31:711-8. [PMID: 20187217 DOI: 10.1002/jmri.22083] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation. MATERIALS AND METHODS Time-resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers. RESULTS Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r = 0.99, limits of agreement = -20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation. CONCLUSION 4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair.
Collapse
Affiliation(s)
- Michael D Hope
- Department of Radiology, University of California, San Francisco, California 94143-0628, USA. )
| | | | | | | | | | | | | | | |
Collapse
|
107
|
Amano Y, Takagi R, Suzuki Y, Sekine T, Kumita S, van Cauteren M. Three-dimensional velocity mapping of thoracic aorta and supra-aortic arteries in takayasu arteritis. J Magn Reson Imaging 2010; 31:1481-5. [DOI: 10.1002/jmri.22007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
108
|
Affiliation(s)
- Carl Johan Carlhäll
- Department of Clinical Physiology, University Hospital and Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | | |
Collapse
|
109
|
Stadlbauer A, Salomonowitz E, van der Riet W, Buchfelder M, Ganslandt O. Insight into the patterns of cerebrospinal fluid flow in the human ventricular system using MR velocity mapping. Neuroimage 2010; 51:42-52. [DOI: 10.1016/j.neuroimage.2010.01.110] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 01/25/2010] [Accepted: 01/29/2010] [Indexed: 10/19/2022] Open
|
110
|
Hope MD, Hope TA, Meadows AK, Ordovas KG, Urbania TH, Alley MT, Higgins CB. Bicuspid Aortic Valve: Four-dimensional MR Evaluation of Ascending Aortic Systolic Flow Patterns. Radiology 2010; 255:53-61. [PMID: 20308444 DOI: 10.1148/radiol.09091437] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Michael D Hope
- Department of Radiology, University of California San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628, USA.
| | | | | | | | | | | | | |
Collapse
|
111
|
Eriksson J, Carlhäll CJ, Dyverfeldt P, Engvall J, Bolger AF, Ebbers T. Semi-automatic quantification of 4D left ventricular blood flow. J Cardiovasc Magn Reson 2010; 12:9. [PMID: 20152026 PMCID: PMC2831022 DOI: 10.1186/1532-429x-12-9] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 02/12/2010] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The beating heart is the generator of blood flow through the cardiovascular system. Within the heart's own chambers, normal complex blood flow patterns can be disturbed by diseases. Methods for the quantification of intra-cardiac blood flow, with its 4D (3D+time) nature, are lacking. We sought to develop and validate a novel semi-automatic analysis approach that integrates flow and morphological data. METHOD In six healthy subjects and three patients with dilated cardiomyopathy, three-directional, three-dimensional cine phase-contrast cardiovascular magnetic resonance (CMR) velocity data and balanced steady-state free-precession long- and short-axis images were acquired. The LV endocardium was segmented from the short-axis images at the times of isovolumetric contraction (IVC) and isovolumetric relaxation (IVR). At the time of IVC, pathlines were emitted from the IVC LV blood volume and traced forwards and backwards in time until IVR, thus including the entire cardiac cycle. The IVR volume was used to determine if and where the pathlines left the LV. This information was used to automatically separate the pathlines into four different components of flow: Direct Flow, Retained Inflow, Delayed Ejection Flow and Residual Volume. Blood volumes were calculated for every component by multiplying the number of pathlines with the blood volume represented by each pathline. The accuracy and inter- and intra-observer reproducibility of the approach were evaluated by analyzing volumes of LV inflow and outflow, the four flow components, and the end-diastolic volume. RESULTS The volume and distribution of the LV flow components were determined in all subjects. The calculated LV outflow volumes [ml] (67 +/- 13) appeared to fall in between those obtained by through-plane phase-contrast CMR (77 +/- 16) and Doppler ultrasound (58 +/- 10), respectively. Calculated volumes of LV inflow (68 +/- 11) and outflow (67 +/- 13) were well matched (NS). Low inter- and intra-observer variability for the assessment of the volumes of the flow components was obtained. CONCLUSIONS This semi-automatic analysis approach for the quantification of 4D blood flow resulted in accurate LV inflow and outflow volumes and a high reproducibility for the assessment of LV flow components.
Collapse
Affiliation(s)
- Jonatan Eriksson
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Carl Johan Carlhäll
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Clinical Physiology, Linköping University Hospital, Linköping, Sweden
| | - Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Division of Applied Thermodynamics and Fluid Mechanics, Department of Management and Engineering, Linköping University, Linköping, Sweden
| | - Jan Engvall
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Clinical Physiology, Linköping University Hospital, Linköping, Sweden
| | - Ann F Bolger
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Department of Medicine, University of California, San Francisco, California, USA
| | - Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Division of Applied Thermodynamics and Fluid Mechanics, Department of Management and Engineering, Linköping University, Linköping, Sweden
| |
Collapse
|
112
|
Bock J, Frydrychowicz A, Stalder AF, Bley TA, Burkhardt H, Hennig J, Markl M. 4D phase contrast MRI at 3 T: Effect of standard and blood-pool contrast agents on SNR, PC-MRA, and blood flow visualization. Magn Reson Med 2010; 63:330-8. [DOI: 10.1002/mrm.22199] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
113
|
den Reijer PM, Sallee D, van der Velden P, Zaaijer ER, Parks WJ, Ramamurthy S, Robbie TQ, Donati G, Lamphier C, Beekman RP, Brummer ME. Hemodynamic predictors of aortic dilatation in bicuspid aortic valve by velocity-encoded cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2010; 12:4. [PMID: 20070904 PMCID: PMC2827385 DOI: 10.1186/1532-429x-12-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 01/13/2010] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Congenital bicuspid aortic valve (BAV) is a significant risk factor for serious complications including valve dysfunction, aortic dilatation, dissection, and sudden death. Clinical tools for identification and monitoring of BAV patients at high risk for development of aortic dilatation, an early complication, are not available. METHODS This paper reports an investigation in 18 pediatric BAV patients and 10 normal controls of links between abnormal blood flow patterns in the ascending aorta and aortic dilatation using velocity-encoded cardiovascular magnetic resonance. Blood flow patterns were quantitatively expressed in the angle between systolic left ventricular outflow and the aortic root channel axis, and also correlated with known biochemical markers of vessel wall disease. RESULTS The data confirm larger ascending aortas in BAV patients than in controls, and show more angled LV outflow in BAV (17.54 +/- 0.87 degrees) than controls (10.01 +/- 1.29) (p = 0.01). Significant correlation of systolic LV outflow jet angles with dilatation was found at different levels of the aorta in BAV patients STJ: r = 0.386 (N = 18, p = 0.048), AAO: r = 0.536 (N = 18, p = 0.022), and stronger correlation was found with patients and controls combined into one population: SOV: r = 0.405 (N = 28, p = 0.033), STJ: r = 0.562 (N = 28, p = 0.002), and AAO r = 0.645 (N = 28, p < 0.001). Dilatation and the flow jet angle were also found to correlate with plasma levels of matrix metallo-proteinase 2. CONCLUSIONS The results of this study provide new insights into the pathophysiological processes underlying aortic dilatation in BAV patients. These results show a possible path towards the development of clinical risk stratification protocols in order to reduce morbidity and mortality for this common congenital heart defect.
Collapse
Affiliation(s)
- P Martijn den Reijer
- Leiden University Medical Center, Leiden, The Netherlands
- Emory University School of Medicine, Atlanta, Georgia, USA
| | - Denver Sallee
- Sibley Heart Center Cardiology, Atlanta, Georgia, USA
- Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | | - W James Parks
- Sibley Heart Center Cardiology, Atlanta, Georgia, USA
- Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | | | | - Carey Lamphier
- Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | |
Collapse
|
114
|
Wong KKL, Tu J, Kelso RM, Worthley SG, Sanders P, Mazumdar J, Abbott D. Cardiac flow component analysis. Med Eng Phys 2009; 32:174-88. [PMID: 20022796 DOI: 10.1016/j.medengphy.2009.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 11/24/2022]
Abstract
In a chamber of the heart, large-scale vortices are shown to exist as the result of the dynamic blood flow and unique morphological changes of the chamber wall. As the cardiovascular flow varies over a cardiac cycle, there is a need for a robust quantification method to analyze its vorticity and circulation. We attempt to measure vortex characteristics by means of two-dimensional vorticity maps and vortex circulation. First, we develop vortex component analysis by segmenting the vortices using an data clustering algorithm before histograms of their vorticity distribution are generated. The next stage is to generate the statistics of the vorticity maps for each phase of the cardiac cycle to allow analysis of the flow. This is followed by evaluating the circulation of each segmented vortex. The proposed approach is dedicated to examining vortices within the human heart chamber. The vorticity field can indicate the strength and number of large-scale vortices in the chamber. We provide the results of the flow analysis after vorticity map segmentation and the statistical properties that characterize the vorticity components. The success of the cardiac measurement and analysis is illustrated by a case study of the right atrium. Our investigation shows that it is possible to utilize a data clustering algorithm to segment vortices after vorticity mapping, and that the vorticity and circulation analysis of a chamber vorticity can provide new insights into the blood flow within the cardiovascular structure.
Collapse
Affiliation(s)
- Kelvin K L Wong
- School of Aerospace, Mechanical & Manufacturing Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia.
| | | | | | | | | | | | | |
Collapse
|
115
|
Yacoub MH, El-Hamamsy I, Said K, Magdi G, Abul Enein F, George R, Rossi A, Olivotto I, Cecchi F. The left ventricular outflow in hypertrophic cardiomyopathy: from structure to function. J Cardiovasc Transl Res 2009; 2:510-7. [PMID: 20560010 DOI: 10.1007/s12265-009-9153-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
Abstract
Left ventricular outflow tract obstruction (LVOTO) is one of the defining features of hypertrophic cardiomyopathy (HCM) and one of the main determinants of prognosis. Although the importance of obstruction was recognized since the original description by Teare and Brock, its exact cause and methods for its relief are still being hotly debated. We believe that a rational approach to solving these issues depends on thorough understanding of the specific structure and functions of the left ventricular outflow tract (LVOT) in health and disease. There is now compelling evidence that the LVOT performs a series of vital sophisticated functions which are mediated by the design characteristics, structure, and biological properties of its component parts and that dysregulation of one or more of these functions results in obstruction and other abnormalities. We here review the integrated functions of the LVOT, its structural and functional relationships, with particular reference to its component parts (the major players) and their role in HCM. This knowledge is essential to evolve tailored restorative techniques for treating HCM.
Collapse
Affiliation(s)
- Magdi H Yacoub
- Harefield Heart Science Center, Harefield Hospital, London, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
116
|
Harloff A, Markl M, Frydrychowicz A, Hennig J, Weiller C. [Diagnosing stroke aetiologies. Morphologic and functional analysis of the aorta and carotid arteries by MRI]. DER NERVENARZT 2009; 80:929-40. [PMID: 19319500 DOI: 10.1007/s00115-009-2679-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Magnetic resonance imaging allows detailed visualization of the thoracic aorta and is not limited by air artefacts or insonation angles like transoesophageal echocardiography (TEE). Thus the aortic arch can be investigated with higher accuracy, and additional embolic high-risk sources such as complex plaques can be additionally detected by MRI in patients with cryptogenic stroke. Furthermore, MRI provides exact 3D plaque localisation and can be combined with multidirectional 3D MRI velocity mapping. In this way, previously not demonstrable retrograde flow paths originating at complex descending aortic plaques reaching the supra-aortic great arteries can be identified as the probable stroke mechanism in certain patients. The same technique can also be applied to the carotid arteries. This allows analysing the complex 3D helical flow within the internal carotid artery as well as measuring absolute flow velocities and wall shear stress in combination with data on vessel anatomy derived from conventional MR angiography. It is the purpose of this work to describe the state of the art of these modern MR imaging techniques and their potential to identify potential stroke mechanisms, and to analyse the particular role of individual haemodynamic factors on the development of local atherosclerosis.
Collapse
Affiliation(s)
- A Harloff
- Abteilung Neurologie, Neurozentrum, Universitätsklinikum, Breisacher Str. 64, 79106 Freiburg.
| | | | | | | | | |
Collapse
|
117
|
Hjortnaes J, Bouten CV, Van Herwerden LA, Gründeman PF, Kluin J. Translating Autologous Heart Valve Tissue Engineering from Bench to Bed. TISSUE ENGINEERING PART B-REVIEWS 2009; 15:307-17. [DOI: 10.1089/ten.teb.2008.0565] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jesper Hjortnaes
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Carlijn V.C. Bouten
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Cell & Tissue Engineering Laboratory, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Lex A. Van Herwerden
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul F. Gründeman
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jolanda Kluin
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
118
|
Frydrychowicz A, Stalder AF, Russe MF, Bock J, Bauer S, Harloff A, Berger A, Langer M, Hennig J, Markl M. Three-dimensional analysis of segmental wall shear stress in the aorta by flow-sensitive four-dimensional-MRI. J Magn Reson Imaging 2009; 30:77-84. [PMID: 19557849 DOI: 10.1002/jmri.21790] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To assess the distribution and regional differences of flow and vessel wall parameters such as wall shear stress (WSS) and oscillatory shear index (OSI) in the entire thoracic aorta. MATERIALS AND METHODS Thirty-one healthy volunteers (mean age = 23.7 +/- 3.3 years) were examined by flow-sensitive four-dimensional (4D)-MRI at 3T. For eight retrospectively positioned 2D analysis planes distributed along the thoracic aorta, flow parameters and vectorial WSS and OSI were assessed in 12 segments along the vascular circumference. RESULTS Mean absolute time-averaged WSS ranged between 0.25 +/- 0.04 N/m(2) and 0.33 +/- 0.07 N/m(2) and incorporated a substantial circumferential component (-0.05 +/- 0.04 to 0.07 +/- 0.02 N/m(2)). For each analysis plane, a segment with lowest absolute WSS and highest OSI was identified which differed significantly from mean values within the plane (P < 0.05). The distribution of atherogenic low WSS and high OSI closely resembled typical locations of atherosclerotic lesions at the inner aortic curvature and supraaortic branches. CONCLUSION The normal distribution of vectorial WSS and OSI in the entire thoracic aorta derived from flow-sensitive 4D-MRI data provides a reference constituting an important perquisite for the examination of patients with aortic disease. Marked regional differences in absolute WSS and OSI may help explaining why atherosclerotic lesions predominantly develop and progress at specific locations in the aorta.
Collapse
Affiliation(s)
- Alex Frydrychowicz
- Department of Diagnostic Radiology and Medical Physics, University Hospital Freiburg, Freiburg, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
119
|
Uribe S, Beerbaum P, Sørensen TS, Rasmusson A, Razavi R, Schaeffter T. Four-dimensional (4D) flow of the whole heart and great vessels using real-time respiratory self-gating. Magn Reson Med 2009; 62:984-92. [DOI: 10.1002/mrm.22090] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
120
|
van Amerom JFP, Vidarsson L, Wu S, Tessler R, Yoo SJ, Belik J, Macgowan CK. Regional pulmonary blood flow: Comparison of dynamic contrast-enhanced MR perfusion and phase-contrast MR. Magn Reson Med 2009; 61:1249-54. [PMID: 19253385 DOI: 10.1002/mrm.21940] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Regional pulmonary blood flow can be assessed using both dynamic contrast-enhanced (DCE) MR and phase-contrast (PC) MR. These methods provide somewhat complementary information: DCE MR can assess flow over the entire lung while PC MR can detect rapid changes in flow to a targeted region. Although both methods are considered accurate, one may be more feasible than the other depending on pathology, patient condition, and availability of an intravenous route. The objective of this study was to establish a consensus between the two methods by comparing paired DCE MR and PC MR measurements of relative blood flow in Yorkshire piglets (N = 5, age = 7 days, weight = 3.3 +/- 0.6 kg) under various physiological states including regional lung collapse. A strong correlation (R(2) = 0.71, P < 0.01) was observed between the methods. In conclusion, DCE MR and PC MR provide a consistent measure of changes in regional pulmonary blood flow.
Collapse
Affiliation(s)
- Joshua F P van Amerom
- Department of Medical Biophysics, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
121
|
Stadlbauer A, van der Riet W, Crelier G, Salomonowitz E. Accelerated time-resolved three-dimensional MR velocity mapping of blood flow patterns in the aorta using SENSE and k-t BLAST. Eur J Radiol 2009; 75:e15-21. [PMID: 19581063 DOI: 10.1016/j.ejrad.2009.06.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 05/13/2009] [Accepted: 06/08/2009] [Indexed: 12/21/2022]
Abstract
PURPOSE To assess the feasibility and potential limitations of the acceleration techniques SENSE and k-t BLAST for time-resolved three-dimensional (3D) velocity mapping of aortic blood flow. Furthermore, to quantify differences in peak velocity versus heart phase curves. MATERIALS AND METHODS Time-resolved 3D blood flow patterns were investigated in eleven volunteers and two patients suffering from aortic diseases with accelerated PC-MR sequences either in combination with SENSE (R=2) or k-t BLAST (6-fold). Both sequences showed similar data acquisition times and hence acceleration efficiency. Flow-field streamlines were calculated and visualized using the GTFlow software tool in order to reconstruct 3D aortic blood flow patterns. Differences between the peak velocities from single-slice PC-MRI experiments using SENSE 2 and k-t BLAST 6 were calculated for the whole cardiac cycle and averaged for all volunteers. RESULTS Reconstruction of 3D flow patterns in volunteers revealed attenuations in blood flow dynamics for k-t BLAST 6 compared to SENSE 2 in terms of 3D streamlines showing fewer and less distinct vortices and reduction in peak velocity, which is caused by temporal blurring. Solely by time-resolved 3D MR velocity mapping in combination with SENSE detected pathologic blood flow patterns in patients with aortic diseases. For volunteers, we found a broadening and flattering of the peak velocity versus heart phase diagram between the two acceleration techniques, which is an evidence for the temporal blurring of the k-t BLAST approach. CONCLUSION We demonstrated the feasibility of SENSE and detected potential limitations of k-t BLAST when used for time-resolved 3D velocity mapping. The effects of higher k-t BLAST acceleration factors have to be considered for application in 3D velocity mapping.
Collapse
Affiliation(s)
- Andreas Stadlbauer
- MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten, Austria.
| | | | | | | |
Collapse
|
122
|
Ebbers T, Farnebäck G. Improving computation of cardiovascular relative pressure fields from velocity MRI. J Magn Reson Imaging 2009; 30:54-61. [PMID: 19557846 DOI: 10.1002/jmri.21775] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
| | | |
Collapse
|
123
|
Hope TA, Zarins CK, Herfkens RJ. Initial experience characterizing a type I endoleak from velocity profiles using time-resolved three-dimensional phase-contrast MRI. J Vasc Surg 2009; 49:1580-4. [DOI: 10.1016/j.jvs.2009.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 12/22/2008] [Accepted: 01/03/2009] [Indexed: 11/16/2022]
|
124
|
Cardiac Flow Analysis Applied to Phase Contrast Magnetic Resonance Imaging of the Heart. Ann Biomed Eng 2009; 37:1495-515. [DOI: 10.1007/s10439-009-9709-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 04/28/2009] [Indexed: 01/05/2023]
|
125
|
Boussel L, Rayz V, Martin A, Acevedo-Bolton G, Lawton MT, Higashida R, Smith WS, Young WL, Saloner D. Phase-contrast magnetic resonance imaging measurements in intracranial aneurysms in vivo of flow patterns, velocity fields, and wall shear stress: comparison with computational fluid dynamics. Magn Reson Med 2009; 61:409-17. [PMID: 19161132 DOI: 10.1002/mrm.21861] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as wall shear stress (WSS) and maximum shear stress (MSS). Estimation of these parameters can be performed using numerical simulations with computational fluid dynamics (CFD), but can also be directly measured with magnetic resonance imaging (MRI) using a time-dependent 3D phase-contrast sequence with encoding of each of the three components of the velocity vectors (7D-MRV). To study the accuracy of 7D-MRV in estimating these parameters in vivo, in comparison with CFD, 7D-MRV and patient-specific CFD modeling was performed for 3 patients who had intracranial aneurysms. Visual and quantitative analyses of the flow pattern and distribution of velocities, MSS, and WSS were performed using the two techniques. Spearman's coefficients of correlation between the two techniques were 0.56 for the velocity field, 0.48 for MSS, and 0.59 for WSS. Visual analysis and Bland-Altman plots showed good agreement for flow pattern and velocities but large discrepancies for MSS and WSS. These results indicate that 7D-MRV can be used in vivo to measure velocity flow fields and for estimating MSS and WSS. Currently, however, this method cannot accurately quantify the latter two parameters.
Collapse
Affiliation(s)
- Loic Boussel
- Radiology Service, VA Medical Center, San Francisco, California 94121, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
126
|
Brix L, Ringgaard S, Rasmusson A, Sørensen TS, Kim WY. Three dimensional three component whole heart cardiovascular magnetic resonance velocity mapping: comparison of flow measurements from 3D and 2D acquisitions. J Cardiovasc Magn Reson 2009; 11:3. [PMID: 19232119 PMCID: PMC2649114 DOI: 10.1186/1532-429x-11-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 02/20/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Two-dimensional, unidirectionally encoded, cardiovascular magnetic resonance (CMR) velocity mapping is an established technique for the quantification of blood flow in large vessels. However, it requires an operator to correctly align the planes of acquisition. If all three directional components of velocity are measured for each voxel of a 3D volume through the phases of the cardiac cycle, blood flow through any chosen plane can potentially be calculated retrospectively. The initial acquisition is then more time consuming but relatively operator independent. AIMS To compare the curves and volumes of flow derived from conventional 2D and comprehensive 3D flow acquisitions in a steady state flow model, and in vivo through planes transecting the ascending aorta and pulmonary trunk in 10 healthy volunteers. METHODS Using a 1.5 T Phillips Intera CMR system, 3D acquisitions used an anisotropic 3D segmented k-space phase contrast gradient echo sequence with a short EPI readout, with prospective ECG and diaphragm navigator gating. The 2D acquisitions used segmented k-space phase contrast with prospective ECG and diaphragm navigator gating. Quantitative flow analyses were performed retrospectively with dedicated software for both the in vivo and in vitro acquisitions. RESULTS Analysis of in vitro data found the 3D technique to have overestimated the continuous flow rate by approximately 5% across the entire applied flow range. In vivo, the 2D and the 3D techniques yielded similar volumetric flow curves and measurements. Aortic flow: (mean +/- SD), 2D = 89.5 +/- 13.5 ml & 3D = 92.7 +/- 17.5 ml. Pulmonary flow: 2D = 98.8 +/- 18.4 ml & 3D = 94.9 +/- 19.0 ml). Each in vivo 3D acquisition took about 8 minutes or more. CONCLUSION Flow measurements derived from the 3D and 2D acquisitions were comparable. Although time consuming, comprehensive 3D velocity acquisition could be relatively operator independent, and could potentially yield information on flow through several retrospectively chosen planes, for example in patients with congenital or valvular heart disease.
Collapse
Affiliation(s)
- Lau Brix
- Department of Biomedical Engineering, Region Midtjylland, c/o Aarhus University Hospital, Skejby, Denmark
- MR-Centre, Aarhus University Hospital, Skejby, Denmark
| | | | - Allan Rasmusson
- Department of Computer Science, University of Aarhus, Aarhus, Denmark
| | - Thomas Sangild Sørensen
- Department of Computer Science, University of Aarhus, Aarhus, Denmark
- Institute of Clinical Medicine, University of Aarhus, Aarhus, Denmark
| | - W Yong Kim
- MR-Centre, Aarhus University Hospital, Skejby, Denmark
- Department of Cardiology, Aarhus University Hospital, Skejby, Denmark
| |
Collapse
|
127
|
Jung B, Honal M, Ullmann P, Hennig J, Markl M. Highly k-t-space-accelerated phase-contrast MRI. Magn Reson Med 2009; 60:1169-77. [PMID: 18958854 DOI: 10.1002/mrm.21764] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The purpose of this study was to combine a recently introduced spatiotemporal parallel imaging technique, PEAK-GRAPPA (parallel MRI with extended and averaged generalized autocalibrating partially parallel acquisition), with two-dimensional (2D) cine phase-contrast velocity mapping. Phase-contrast MRI was applied to measure the blood flow in the thoracic aorta and the myocardial motion of the left ventricle. To evaluate the performance of different reconstruction methods, fully acquired k-space data sets were used to compare conventional parallel imaging using GRAPPA with reduction factors of R = 2-6 and PEAK-GRAPPA as well as sliding window reconstruction with reduction factors R = 2-12 (net acceleration factors up to 5.2). PEAK-GRAPPA reconstruction resulted in improved image quality with considerably reduced artifacts, which was also supported by error analysis. To analyze potential blurring or low-pass filtering effects of spatiotemporal PEAK-GRAPPA, the velocity time courses of aortic flow and myocardial tissue motion were evaluated and compared with conventional image reconstructions. Quantitative comparisons of blood flow velocities and pixel-wise correlation analysis of velocities highlight the potential of PEAK-GRAPPA for highly accelerated dynamic phase-contrast velocity mapping.
Collapse
Affiliation(s)
- Bernd Jung
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany.
| | | | | | | | | |
Collapse
|
128
|
Hope MD, Purcell DD, Hope TA, von Morze C, Vigneron DB, Alley MT, Dillon WP. Complete intracranial arterial and venous blood flow evaluation with 4D flow MR imaging. AJNR Am J Neuroradiol 2009; 30:362-6. [PMID: 18653687 DOI: 10.3174/ajnr.a1138] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARY Time-resolved, 3D velocity-encoded MR imaging (4D Flow) allows for the acquisition of dynamic, multidirectional data on blood flow and has recently been used for the evaluation of intracranial arterial flow. Using a 3T system with optimization of both temporal resolution and k-space subsampling with a combination of parallel imaging and cut-corner acquisition, we present the clinical assessment of a patient with an arteriovenous malformation by providing complete intracranial arterial and venous coverage in a reasonable scan time.
Collapse
Affiliation(s)
- M D Hope
- Department of Radiology, University of California, San Francisco, CA 94143-0628, USA.
| | | | | | | | | | | | | |
Collapse
|
129
|
In Vivo Quantification of Helical Blood Flow in Human Aorta by Time-Resolved Three-Dimensional Cine Phase Contrast Magnetic Resonance Imaging. Ann Biomed Eng 2008; 37:516-31. [DOI: 10.1007/s10439-008-9609-6] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 11/20/2008] [Indexed: 12/21/2022]
|
130
|
Hope TA, Herfkens RJ. Imaging of the Thoracic Aorta with Time-Resolved Three-Dimensional Phase-Contrast MRI: A Review. Semin Thorac Cardiovasc Surg 2008; 20:358-64. [DOI: 10.1053/j.semtcvs.2008.11.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2008] [Indexed: 11/11/2022]
|
131
|
Simulation of blood flow in a small-diameter vascular graft model with a swirl (spiral) flow guider. ACTA ACUST UNITED AC 2008; 51:913-21. [DOI: 10.1007/s11427-008-0118-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 06/22/2008] [Indexed: 11/27/2022]
|
132
|
Nobili M, Morbiducci U, Ponzini R, Del Gaudio C, Balducci A, Grigioni M, Maria Montevecchi F, Redaelli A. Numerical simulation of the dynamics of a bileaflet prosthetic heart valve using a fluid–structure interaction approach. J Biomech 2008; 41:2539-50. [DOI: 10.1016/j.jbiomech.2008.05.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 04/04/2008] [Accepted: 05/06/2008] [Indexed: 10/21/2022]
|
133
|
Frydrychowicz A, Berger A, Russe MF, Stalder AF, Harloff A, Dittrich S, Hennig J, Langer M, Markl M. Time-resolved magnetic resonance angiography and flow-sensitive 4-dimensional magnetic resonance imaging at 3 Tesla for blood flow and wall shear stress analysis. J Thorac Cardiovasc Surg 2008; 136:400-7. [DOI: 10.1016/j.jtcvs.2008.02.062] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 12/26/2007] [Accepted: 02/19/2008] [Indexed: 11/28/2022]
|
134
|
Weber TF, Ganten MK, Böckler D, Geisbüsch P, Kopp-Schneider A, Kauczor HU, von Tengg-Kobligk H. Assessment of thoracic aortic conformational changes by four-dimensional computed tomography angiography in patients with chronic aortic dissection type b. Eur Radiol 2008; 19:245-53. [DOI: 10.1007/s00330-008-1103-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 05/18/2008] [Accepted: 06/02/2008] [Indexed: 10/21/2022]
|
135
|
Weigang E, Kari FA, Beyersdorf F, Luehr M, Etz CD, Frydrychowicz A, Harloff A, Markl M. Flow-sensitive four-dimensional magnetic resonance imaging: flow patterns in ascending aortic aneurysms. Eur J Cardiothorac Surg 2008; 34:11-6. [DOI: 10.1016/j.ejcts.2008.03.047] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 03/18/2008] [Accepted: 03/19/2008] [Indexed: 10/22/2022] Open
|
136
|
Hope MD, Meadows AK, Hope TA, Ordovas KG, Reddy GP, Alley MT, Higgins CB. Images in cardiovascular medicine. Evaluation of bicuspid aortic valve and aortic coarctation with 4D flow magnetic resonance imaging. Circulation 2008; 117:2818-9. [PMID: 18506021 DOI: 10.1161/circulationaha.107.760124] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Michael D Hope
- Department of Radiology, University of California, San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628, USA.
| | | | | | | | | | | | | |
Collapse
|
137
|
Canstein C, Cachot P, Faust A, Stalder AF, Bock J, Frydrychowicz A, Küffer J, Hennig J, Markl M. 3D MR flow analysis in realistic rapid-prototyping model systems of the thoracic aorta: comparison with in vivo data and computational fluid dynamics in identical vessel geometries. Magn Reson Med 2008; 59:535-46. [PMID: 18306406 DOI: 10.1002/mrm.21331] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The knowledge of local vascular anatomy and function in the human body is of high interest for the diagnosis and treatment of cardiovascular disease. A comprehensive analysis of the hemodynamics in the thoracic aorta is presented based on the integration of flow-sensitive 4D MRI with state-of-the-art rapid prototyping technology and computational fluid dynamics (CFD). Rapid prototyping was used to transform aortic geometries as measured by contrast-enhanced MR angiography into realistic vascular models with large anatomical coverage. Integration into a flow circuit with patient-specific pulsatile in-flow conditions and application of flow-sensitive 4D MRI permitted detailed analysis of local and global 3D flow dynamics in a realistic vascular geometry. Visualization of characteristic 3D flow patterns and quantitative comparisons of the in vitro experiments with in vivo data and CFD simulations in identical vascular geometries were performed to evaluate the accuracy of vascular model systems. The results indicate the potential of such patient-specific model systems for detailed experimental simulation of realistic vascular hemodynamics. Further studies are warranted to examine the influence of refined boundary conditions of the human circulatory system such as fluid-wall interaction and their effect on normal and pathological blood flow characteristics associated with vascular geometry.
Collapse
Affiliation(s)
- C Canstein
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
138
|
|
139
|
Unterhinninghofen R, Ley S, Ley-Zaporozhan J, von Tengg-Kobligk H, Bock M, Kauczor HU, Szabó G, Dillmann R. Concepts for visualization of multidirectional phase-contrast MRI of the heart and large thoracic vessels. Acad Radiol 2008; 15:361-9. [PMID: 18280934 DOI: 10.1016/j.acra.2007.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 11/19/2007] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
Abstract
RATIONALE AND OBJECTIVES Multidirectional phase-contrast magnetic resonance imaging allows the acquisition of time-resolved velocity fields (vectors) of cardiac and vascular blood flow. Its unique ability to provide vectorial flow information promises to give new insights into hemodynamic physiology. However, up to now appropriate and standardized procedures and software tools are missing to take advantage of all the information contained in the data. The objective of this work is to present a new versatile software tool and to demonstrate its practical value for the examination of multidirectional blood flow. MATERIALS AND METHODS An exemplary selection of data sets from healthy volunteers, patients with cardiovascular pathologies, and healthy domestic pigs has been acquired using a phase-contrast magnetic resonance imaging sequence based on FLASH (fast low angle shot) that encodes velocity as field of three-dimensional vectors. For data processing, we have developed a software tool that integrates the whole workflow, including noise filtering, interactive visualization, and flow quantification. RESULTS Using the software tool visualization of complex flow data is easily generated within 5 minutes; interactive exploration of the data is possible in real-time. Exemplary physiologic and pathologic flow patterns were visualized in an intuitive manner. The visual results suggest valuable diagnostic information; its significance, however, must be further evaluated together with the development of more specific data processing. CONCLUSIONS Multidirectional phase-contrast magnetic resonance imaging is a valuable tool for assessment of cardiac and vascular hemodynamics. With the development of tools that offer standardized and thus comparable visualizations it may be integrated into the clinical routine in the near future.
Collapse
Affiliation(s)
- Roland Unterhinninghofen
- Institute of Computer Science and Engineering, University of Karlsruhe, Haid-und-Neu-Str. 7, 76131, Karlsruhe, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
140
|
Lum DP, Johnson KM, Paul RK, Turk AS, Consigny DW, Grinde JR, Mistretta CA, Grist TM. Transstenotic Pressure Gradients: Measurement in Swine—Retrospectively ECG-gated 3D Phase-Contrast MR Angiography versus Endovascular Pressure-sensing Guidewires. Radiology 2007; 245:751-60. [PMID: 18024452 DOI: 10.1148/radiol.2453061946] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Darren P Lum
- Department of Radiology, University of Wisconsin Hospital and Clinics, 600 Highland Ave, CSC E3/311, Madison, WI 53792, USA.
| | | | | | | | | | | | | | | |
Collapse
|
141
|
Cheng A, Dagum P, Miller DC. Aortic root dynamics and surgery: from craft to science. Philos Trans R Soc Lond B Biol Sci 2007; 362:1407-19. [PMID: 17594968 PMCID: PMC2440404 DOI: 10.1098/rstb.2007.2124] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Since the fifteenth century beginning with Leonardo da Vinci's studies, the precise structure and functional dynamics of the aortic root throughout the cardiac cycle continues to elude investigators. The last five decades of experimental work have contributed substantially to our current understanding of aortic root dynamics. In this article, we review and summarize the relevant structural analyses, using radiopaque markers and sonomicrometric crystals, concerning aortic root three-dimensional deformations and describe aortic root dynamics in detail throughout the cardiac cycle. We then compare data between different studies and discuss the mechanisms responsible for the modes of aortic root deformation, including the haemodynamics, anatomical and temporal determinants of those deformations. These modes of aortic root deformation are closely coupled to maximize ejection, optimize transvalvular ejection haemodynamics and-perhaps most importantly-reduce stress on the aortic valve cusps by optimal diastolic load sharing and minimizing transvalvular turbulence throughout the cardiac cycle. This more comprehensive understanding of aortic root mechanics and physiology will contribute to improved medical and surgical treatment methods, enhanced therapeutic decision making and better post-intervention care of patients. With a better understanding of aortic root physiology, future research on aortic valve repair and replacement should take into account the integrated structural and functional asymmetry of aortic root dynamics to minimize stress on the aortic cusps in order to prevent premature structural valve deterioration.
Collapse
Affiliation(s)
| | | | - D. Craig Miller
- Author and address for correspondence: Department of Cardiothoracic Surgery, Falk Cardiovascular Research Centre, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5247, USA ()
| |
Collapse
|
142
|
Abstract
Phase-contrast flow measurements have become an established method in cardiac MRI. The quantification of intra- and extracardiac shunt volumes as well as the evaluation of valvular disease and aortic coarctation have proved their clinical usefulness. There are some rules that have to be followed when performing and analyzing phase-contrast flow measurements. With these rules in mind, quantitative phase-contrast flow measurements are a reliable and precise method for clinical use of cardiac MRI.
Collapse
Affiliation(s)
- J Lotz
- Institut für Diagnostische Radiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625, Hannover, Deutschland.
| |
Collapse
|
143
|
Frydrychowicz A, Winterer JT, Zaitsev M, Jung B, Hennig J, Langer M, Markl M. Visualization of iliac and proximal femoral artery hemodynamics using time-resolved 3D phase contrast MRI at 3T. J Magn Reson Imaging 2007; 25:1085-92. [PMID: 17427916 DOI: 10.1002/jmri.20900] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of time-resolved 3D MR velocity mapping at 3 Tesla for the visualization of vascular hemodynamics in normal iliac and femoral arteries. MATERIALS AND METHODS Electrocardiographically (ECG) synchronized three-dimensional (3D) CINE phase-contrast MRI with three-directional flow encoding was adapted to analyze flow in peripheral arteries at 3T. Visualization of peripheral arterial hemodynamics within the acquired data volume included 3D streamlines and time-resolved 3D particle traces within the major vessels and localized analysis of flow profiles using 2D-vector graphs. Data was visually compared to results from color-coded duplex ultrasound (US). RESULTS Global and detailed local blood flow characteristics were successfully analyzed in all subjects. In agreement with US findings, normal laminar flow patterns without flow acceleration or disturbances were visualized in all healthy individuals. In an exemplary patient measurement multiple segmental flow accelerations could be demonstrated. MRI additionally revealed complex helical flow alterations distal to a moderate stenosis. CONCLUSION Due to the full spatial and temporal coverage of the arteries of interest, 3D CINE phase contrast MRI at 3T is a promising tool for the evaluation of vascular hemodynamics in peripheral arteries. Future methodological improvements will be directed to improve spatial and temporal resolution as well as quantitative data analysis. Moreover, the technique will have to be evaluated in patients in comparison to standard diagnostic tools.
Collapse
Affiliation(s)
- Alex Frydrychowicz
- Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
144
|
Markl M, Harloff A, Bley TA, Zaitsev M, Jung B, Weigang E, Langer M, Hennig J, Frydrychowicz A. Time-resolved 3D MR velocity mapping at 3T: improved navigator-gated assessment of vascular anatomy and blood flow. J Magn Reson Imaging 2007; 25:824-31. [PMID: 17345635 DOI: 10.1002/jmri.20871] [Citation(s) in RCA: 297] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To evaluate an improved image acquisition and data-processing strategy for assessing aortic vascular geometry and 3D blood flow at 3T. MATERIALS AND METHODS In a study with five normal volunteers and seven patients with known aortic pathology, prospectively ECG-gated cine three-dimensional (3D) MR velocity mapping with improved navigator gating, real-time adaptive k-space ordering and dynamic adjustment of the navigator acceptance criteria was performed. In addition to morphological information and three-directional blood flow velocities, phase-contrast (PC)-MRA images were derived from the same data set, which permitted 3D isosurface rendering of vascular boundaries in combination with visualization of blood-flow patterns. RESULTS Analysis of navigator performance and image quality revealed improved scan efficiencies of 63.6%+/-10.5% and temporal resolution (<50 msec) compared to previous implementations. Semiquantitative evaluation of image quality by three independent observers demonstrated excellent general image appearance with moderate blurring and minor ghosting artifacts. Results from volunteer and patient examinations illustrate the potential of the improved image acquisition and data-processing strategy for identifying normal and pathological blood-flow characteristics. CONCLUSION Navigator-gated time-resolved 3D MR velocity mapping at 3T in combination with advanced data processing is a powerful tool for performing detailed assessments of global and local blood-flow characteristics in the aorta to describe or exclude vascular alterations.
Collapse
Affiliation(s)
- Michael Markl
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
145
|
Frydrychowicz A, Harloff A, Jung B, Zaitsev M, Weigang E, Bley TA, Langer M, Hennig J, Markl M. Time-resolved, 3-dimensional magnetic resonance flow analysis at 3 T: visualization of normal and pathological aortic vascular hemodynamics. J Comput Assist Tomogr 2007; 31:9-15. [PMID: 17259827 DOI: 10.1097/01.rct.0000232918.45158.c9] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Flow-sensitive 3-dimensional magnetic resonance imaging at 3 T and advanced 3-dimensional visualization were used to visualize local and global vascular hemodynamics in the thoracic aorta. In patients with pathological geometric alterations of the thoracic aorta, this technique revealed considerable changes in local blood flow characteristics, compared with normal volunteers. Specifically, relatively small geometric changes, such as a partially thrombosed aortic arch or a mild aneurysm of the ascending aorta, resulted in major disturbances of local blood flow patterns within and even further downstream to the pathology.
Collapse
Affiliation(s)
- Alex Frydrychowicz
- Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
146
|
Bammer R, Hope TA, Aksoy M, Alley MT. Time-resolved 3D quantitative flow MRI of the major intracranial vessels: initial experience and comparative evaluation at 1.5T and 3.0T in combination with parallel imaging. Magn Reson Med 2007; 57:127-40. [PMID: 17195166 PMCID: PMC3985842 DOI: 10.1002/mrm.21109] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Exact knowledge of blood flow characteristics in the major cerebral vessels is of great relevance for diagnosing cerebrovascular abnormalities. This involves the assessment of hemodynamically critical areas as well as the derivation of biomechanical parameters such as wall shear stress and pressure gradients. A time-resolved, 3D phase-contrast (PC) MRI method using parallel imaging was implemented to measure blood flow in three dimensions at multiple instances over the cardiac cycle. The 4D velocity data obtained from 14 healthy volunteers were used to investigate dynamic blood flow with the use of multiplanar reformatting, 3D streamlines, and 4D particle tracing. In addition, the effects of magnetic field strength, parallel imaging, and temporal resolution on the data were investigated in a comparative evaluation at 1.5T and 3T using three different parallel imaging reduction factors and three different temporal resolutions in eight of the 14 subjects. Studies were consistently performed faster at 3T than at 1.5T because of better parallel imaging performance. A high temporal resolution (65 ms) was required to follow dynamic processes in the intracranial vessels. The 4D flow measurements provided a high degree of vascular conspicuity. Time-resolved streamline analysis provided features that have not been reported previously for the intracranial vasculature.
Collapse
Affiliation(s)
- Roland Bammer
- Lucas Center, Department of Radiology, Stanford University, Stanford, California 94305-5488, USA.
| | | | | | | |
Collapse
|
147
|
Fluss-sensitive 4D Magnetresonanztomographie. ZEITSCHRIFT FUR HERZ THORAX UND GEFASSCHIRURGIE 2007. [DOI: 10.1007/s00398-007-0566-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
148
|
Yamashita S, Isoda H, Hirano M, Takeda H, Inagawa S, Takehara Y, Alley MT, Markl M, Pelc NJ, Sakahara H. Visualization of hemodynamics in intracranial arteries using time-resolved three-dimensional phase-contrast MRI. J Magn Reson Imaging 2007; 25:473-8. [PMID: 17279504 DOI: 10.1002/jmri.20828] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To visualize the hemodynamics of the intracranial arteries using time-resolved three-dimensional phase-contrast (PC)-MRI (4D-Flow). MATERIALS AND METHODS MR examinations were performed with a 1.5T MR unit on six healthy volunteers (22-50 years old, average = 30 years). 4D-Flow was based on a radiofrequency (RF)-spoiled gradient-echo sequence, and velocity encoding (VENC) was performed along all three spatial directions. Measurements were retrospectively gated to the electrocardiogram (ECG), and cine series of three-dimensional (3D) data sets were generated. The voxel size was 1 x 1 x 1 mm, and acquisition time was 30-40 minutes. 4D data sets were calculated into time-resolved images of 3D streamlines, 3D particle traces, and 2D velocity vector fields by means of flow visualization software. RESULTS We were able to see the 3D streamlines from the circle of Willis to the bilateral M2 segment of the middle cerebral arteries (MCAs). Time-resolved images of 3D particle traces also clearly demonstrated intracranial arterial flow dynamics. 2D velocity vector fields on the planes traversing the carotid siphon or the basilar tip were clearly visualized. These results were obtained in all six volunteers. CONCLUSION 4D-Flow helped to elucidate the in vivo 3D hemodynamics of human intracranial arteries. This method may be a useful noninvasive means of analyzing the hemodynamics of intracranial arteries in vivo.
Collapse
Affiliation(s)
- Shuhei Yamashita
- Department of Radiology, Hamamatsu University School of Medicine, Shizuoka, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
149
|
Hope TA, Markl M, Wigström L, Alley MT, Miller DC, Herfkens RJ. Comparison of flow patterns in ascending aortic aneurysms and volunteers using four-dimensional magnetic resonance velocity mapping. J Magn Reson Imaging 2007; 26:1471-9. [PMID: 17968892 DOI: 10.1002/jmri.21082] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Thomas A Hope
- Department of Radiology, Stanford University, Stanford, California 94304, USA
| | | | | | | | | | | |
Collapse
|
150
|
Fitzgerald TN, Muto A, Kudo FA, Pimiento JM, Constable RT, Dardik A. Emerging vascular applications of magnetic resonance imaging: a picture is worth more than a thousand words. Vascular 2006; 14:366-71. [PMID: 17150158 DOI: 10.2310/6670.2006.00062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vascular applications of magnetic resonance (MR) imaging are reviewed, with emphasis on algorithms that use nonpictorial information contained in the MR data set. Current clinical vascular practice generally limits use of MR angiography and three-dimensional vessel images to qualitative pictorial rendering without routinely using the available quantitative information contained within the MR data. This review is dedicated to recent advances that include characterization of vessel histology, assessment of carotid plaque vulnerability, characterization of blood flow dynamics, quantitative analysis of disease severity, and prediction of vascular intervention outcome. Examples from histologic preparation, in vitro and in vivo experiments, are discussed, with an emphasis on potential clinical applications and advances in acquisition technology.
Collapse
Affiliation(s)
- Tamara N Fitzgerald
- Department of Surgery, Yale University School of Medicine, New Haven, CT 06519, USA
| | | | | | | | | | | |
Collapse
|