1
|
Knapp J, Tavares de Sousa M, Schönnagel BP. Fetal Cardiovascular MRI - A Systemic Review of the Literature: Challenges, New Technical Developments, and Perspectives. ROFO-FORTSCHR RONTG 2022; 194:841-851. [PMID: 35905903 DOI: 10.1055/a-1761-3500] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND Fetal magnetic resonance imaging (MRI) has become a valuable adjunct to ultrasound in the prenatal diagnosis of congenital pathologies of the central nervous system, thorax, and abdomen. Fetal cardiovascular magnetic resonance (CMR) was limited, mainly by the lack of cardiac gating, and has only recently evolved due to technical developments. METHOD A literature search was performed on PubMed, focusing on technical advancements to perform fetal CMR. In total, 20 publications on cardiac gating techniques in the human fetus were analyzed. RESULTS Fetal MRI is a safe imaging method with no developmental impairments found to be associated with in utero exposure to MRI. Fetal CMR is challenging due to general drawbacks (e. g., fetal motion) and specific limitations such as the difficulty to generate a cardiac gating signal to achieve high spatiotemporal resolution. Promising technical advancements include new methods for fetal cardiac gating, based on novel post-processing approaches and an external hardware device, as well as motion compensation and acceleration techniques. CONCLUSION Newly developed direct and indirect gating approaches were successfully applied to achieve high-quality morphologic and functional imaging as well as quantitative assessment of fetal hemodynamics in research settings. In cases when prenatal echocardiography is limited, e. g., by an unfavorable fetal position in utero, or when its results are inconclusive, fetal CMR could potentially serve as a valuable adjunct in the prenatal assessment of congenital cardiovascular malformations. However, sufficient data on the diagnostic performance and clinical benefit of new fetal CMR techniques is still lacking. KEY POINTS · New fetal cardiac gating methods allow high-quality fetal CMR.. · Motion compensation and acceleration techniques allow for improvement of image quality.. · Fetal CMR could potentially serve as an adjunct to fetal echocardiography in the future.. CITATION FORMAT · Knapp J, Tavares de Sousa M, Schönnagel BP. Fetal Cardiovascular MRI - A Systemic Review of the Literature: Challenges, New Technical Developments, and Perspectives. Fortschr Röntgenstr 2022; 194: 841 - 851.
Collapse
Affiliation(s)
- Janine Knapp
- Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Björn P Schönnagel
- Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
2
|
Magdoom KN, Zeinomar A, Lonser RR, Sarntinoranont M, Mareci TH. Phase contrast MRI of creeping flows using stimulated echo. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 299:49-58. [PMID: 30579226 PMCID: PMC6402592 DOI: 10.1016/j.jmr.2018.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/10/2018] [Accepted: 12/13/2018] [Indexed: 05/30/2023]
Abstract
Creeping flows govern many important physiological phenomena such as elevated interstitial fluid flows in tumors, glymphatic flows in the brain, among other applications. However, few methods exist to measure such slow flows non-invasively in optically opaque biological tissues in vivo. Phase-contrast MRI is a velocimetry technique routinely used in the clinic to measure fast flows in biological tissues, such as blood and cerebrospinal fluid (CSF), in the order of cm/s. Use of this technique to encode slower flows is hampered by diffusion weighting and phase error introduced by gradient hardware imperfections. In this study, a new PC-MRI technique is developed using stimulated echo preparation to overcome these challenges. Flows as slow as 1 μm/s are measured and validated using controlled water flow through a pipe at 4.7 T. The error in measured flow rate obtained by integrating the measured velocity over the cross-sectional area of the pipe is less than 10%. The developed method was also able to capture slow natural convection flows appearing in liquids placed inside a horizontal bore magnet. Monitoring the 4D velocity vector field revealed that the natural convection flows decay exponentially with time. This method could be applied in future to study creeping flows, e.g. in tissue.
Collapse
Affiliation(s)
- Kulam Najmudeen Magdoom
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA.
| | - Ahmad Zeinomar
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Russell R Lonser
- Department of Neurological Surgery, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Malisa Sarntinoranont
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL, USA
| | - Thomas H Mareci
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL, USA
| |
Collapse
|
3
|
Fetal dynamic phase-contrast MR angiography using ultrasound gating and comparison with Doppler ultrasound measurements. Eur Radiol 2019; 29:4169-4176. [PMID: 30617486 DOI: 10.1007/s00330-018-5940-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To investigate the feasibility of fetal phase-contrast (PC)-MR angiography of the descending aorta (AoD) using an MR-compatible Doppler ultrasound sensor (DUS) for fetal cardiac gating and to compare velocimetry with Doppler ultrasound measurements. METHODS In this prospective study, 2D PC-MR angiography was performed in 12 human fetuses (mean gestational age 32.8 weeks) using an MR-compatible DUS for gating of the fetal heart at 1.5 T. Peak flow velocities in the fetal AoD were compared with Doppler ultrasound measurements performed on the same day. Reproducibility of PC-MR measurements was tested by repeated PC-MR in five fetuses. RESULTS Dynamic PC-MR angiography in the AoD was successfully performed in all fetuses using the DUS, with an average fetal heart rate of 140 bpm (range 129-163). Time-velocity curves revealed typical arterial blood flow patterns. PC-MR mean flow velocity and mean flux were 21.2 cm/s (range 8.6-36.8) and 8.4 ml/s (range 3.2-14.6), respectively. A positive association between PC-MR mean flux and stroke volume with gestational age was obtained (r = 0.66, p = 0.02 and r = 0.63, p = 0.03). PC-MR and Doppler ultrasound peak velocities revealed a highly significant correlation (r = 0.8, p < 0.002). Peak velocities were lower for PC-MR with 69.1 cm/s (range 39-125) compared with 96.7 cm/s (range 60-142) for Doppler ultrasound (p < 0.001). Reproducibility of PC-MR was high (p > 0.05). CONCLUSION The MR-compatible DUS for fetal cardiac gating allows for PC-MR angiography in the fetal AoD. Comparison with Doppler ultrasound revealed a highly significant correlation of peak velocities with underestimation of PC-MR velocities. This new technique for direct fetal cardiac gating indicates the potential of PC-MR angiography for assessing fetal hemodynamics. KEY POINTS • The developed MR-compatible Doppler ultrasound sensor allows direct fetal cardiac gating and can be used for prenatal dynamic cardiovascular MRI. • The MR-compatible Doppler ultrasound sensor was successfully applied to perform intrauterine phase-contrast MR angiography of the fetal aorta, which revealed a highly significant correlation with Doppler ultrasound measurements. • As fetal flow hemodynamics is an important parameter in the diagnosis and management of fetal pathologies, fetal phase-contrast MR angiography may offer an alternative imaging method in addition to Doppler ultrasound and develop as a second line tool in the evaluation of fetal flow hemodynamics.
Collapse
|
4
|
Abstract
4D flow MRI permits a comprehensive in-vivo assessment of three-directional blood flow within 3-dimensional vascular structures throughout the cardiac cycle. Given the large coverage permitted from a 4D flow acquisition, the distribution of vessel wall and flow parameters along an entire vessel of interest can thus be derived from a single measurement without being dependent on multiple predefined 2D acquisitions. In addition to qualitative 3D visualizations of complex cardiac and vascular flow patterns, quantitative flow analysis can be performed and is complemented by the ability to compute sophisticated hemodynamic parameters, such as wall shear stress or 3D pressure difference maps. These metrics can provide information previously unavailable with conventional modalities regarding the impact of cardiovascular disease or therapy on global and regional changes in hemodynamics. This review provides an introduction to the methodological aspects of 4D flow MRI to assess vascular hemodynamics and describes its potential for the assessment and understanding of altered hemodynamics in the presence of cardiovascular disease.
Collapse
|
5
|
Körperich H, Barth P, Gieseke J, Müller K, Burchert W, Esdorn H, Kececioglu D, Beerbaum P, Laser KT. Impact of respiration on stroke volumes in paediatric controls and in patients after Fontan procedure assessed by MR real-time phase-velocity mapping. Eur Heart J Cardiovasc Imaging 2014; 16:198-209. [PMID: 25246504 DOI: 10.1093/ehjci/jeu179] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
AIMS Blood flow rate quantification using two-dimensional phase-contrast MRI (PC-MRI) results in averaging of flow information due to long acquisition times precluding the examination of short-term effects. The aim of this study was to determine respiration-related flow rate variations by non-electrocardiographic triggered real-time phase-contrast MRI (PC-MRI). METHODS AND RESULTS Real-time PC-MRI was applied to study respiration-driven blood flow fluctuations in the ascending aorta (AAo), superior vena cava (SVC), and inferior vena cava (IVC) under normal and forced breathing in 33 healthy children and 10 Fontan patients. Respiration-dependent flow rates were virtually generated by dividing the respiration curve into four segments: expiration, end-expiration, inspiration, and end-inspiration. Whereas in volunteers aortic flow rate was elevated during end-expiration (5.6 ± 3.0%) and decreased during end-inspiration (-5.8 ± 3.5%) in relation to mean blood flow (P < 0.05), highest flow was detected during inspiration in SVC (10.5 ± 14.1%) and IVC (22.5 ± 12.1%) and lowest flow during expiration (-11.6 ± 13.5%, -13.2 ± 14.1%, P < 0.05). Differences were increased under forced breathing in AAo (10.4 ± 5.5%, -7.4 ± 6.5%, P < 0.05) and SVC (40.0 ± 30.3%, -30.0 ± 19.2%, P < 0.05), whereas were unchanged in IVC (16.5 ± 23.6%, -13.7 ± 21.6%, P = n.s.). Regarding patients, respiratory-dependent flow rate variability was increased and had to be related to the patient's individual quality of Fontan circulation. CONCLUSION Real-time PC-MRI allows a physiological assessment of respiratory-related flow rate fluctuations in healthy subjects as well as in Fontan patients. Its capability for detection of short-term effects in clinical routine was demonstrated.
Collapse
Affiliation(s)
- Hermann Körperich
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
| | - Peter Barth
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
| | | | - Katja Müller
- Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Wolfgang Burchert
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
| | - Hermann Esdorn
- Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
| | - Deniz Kececioglu
- Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| | - Philipp Beerbaum
- Medizinische Hochschule Hannover, Kinderheilkunde, Pädiatrische Kardiologie und Pädiatrische Intensivmedizin, Hannover, Germany
| | - Kai Thorsten Laser
- Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany
| |
Collapse
|
6
|
Hilbert F, Wech T, Hahn D, Köstler H. Accelerated radial Fourier-velocity encoding using compressed sensing. Z Med Phys 2014; 24:190-200. [DOI: 10.1016/j.zemedi.2013.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/02/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
|
7
|
Lee D, Santos JM, Hu BS, Pauly JM, Kerr AB. Reducing artifacts in one-dimensional Fourier velocity encoding for fast and pulsatile flow. Magn Reson Med 2012; 68:1876-85. [PMID: 22457248 PMCID: PMC3499673 DOI: 10.1002/mrm.24212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 12/27/2011] [Accepted: 01/20/2012] [Indexed: 11/08/2022]
Abstract
When evaluating the severity of valvular stenosis, the peak velocity of the blood flow is routinely used to estimate the transvalvular pressure gradient. One-dimensional Fourier velocity encoding effectively detects the peak velocity with an ungated time series of spatially resolved velocity spectra in real time. However, measurement accuracy can be degraded by the pulsatile and turbulent nature of stenotic flow and the existence of spatially varying off-resonance. In this work, we investigate the feasibility of improving the peak velocity detection capability of one-dimensional Fourier velocity encoding for stenotic flow using a novel echo-shifted interleaved readout combined with a variable-density circular k-space trajectory. The shorter echo and readout times of the echo-shifted interleaved acquisitions are designed to reduce sensitivity to off-resonance. Preliminary results from limited phantom and in vivo results also indicate that some artifacts from pulsatile flow appear to be suppressed when using this trajectory compared to conventional single-shot readouts, suggesting that peak velocity detection may be improved. The efficiency of the new trajectory improves the temporal and spatial resolutions. To realize the proposed readout, a novel multipoint-traversing algorithm is introduced for flexible and automated gradient-waveform design.
Collapse
Affiliation(s)
- Daeho Lee
- Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
| | | | | | | | | |
Collapse
|
8
|
Steeden JA, Jones A, Pandya B, Atkinson D, Taylor AM, Muthurangu V. High-resolution slice-selective Fourier velocity encoding in congenital heart disease using spiral SENSE with velocity unwrap. Magn Reson Med 2012; 67:1538-46. [DOI: 10.1002/mrm.24293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/28/2012] [Accepted: 03/22/2012] [Indexed: 11/09/2022]
|
9
|
Cardiac Magnetic Resonance in Hypertrophic Cardiomyopathy. JACC Cardiovasc Imaging 2011; 4:1123-37. [DOI: 10.1016/j.jcmg.2011.06.022] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 05/27/2011] [Accepted: 06/29/2011] [Indexed: 01/19/2023]
|
10
|
Macgowan CK, Liu GKC, van Amerom JFP, Sussman MS, Wright GA. Self-gated Fourier velocity encoding. Magn Reson Imaging 2009; 28:95-102. [PMID: 19553052 DOI: 10.1016/j.mri.2009.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 04/01/2009] [Accepted: 05/11/2009] [Indexed: 11/26/2022]
Abstract
Self-gating is investigated to improve the velocity resolution of real-time Fourier velocity encoding measurements in the absence of a reliable electrocardiogram waveform (e.g., fetal magnetic resonance or severe arrhythmia). Real-time flow data are acquired using interleaved k-space trajectories which share a common path near the origin of k-space. These common data provide a rapid self-gating signal that can be used to combine the interleaved data. The combined interleaves cover a greater area of k-space than a single real-time acquisition, thereby providing higher velocity resolution for a given aliasing velocity and temporal resolution. For example, this approach provided velocity spectra with a temporal resolution of 19 ms and velocity resolution of 22 cm/s over an 818 cm/s field-of-view. The method was validated experimentally using a computer-controlled pulsatile flow apparatus and applied in vivo to measure aortic-valve flow in a healthy volunteer.
Collapse
Affiliation(s)
- Christopher K Macgowan
- Department of Medical Biophysics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
| | | | | | | | | |
Collapse
|
11
|
Stadlbauer A, van der Riet W, Globits S, Crelier G, Salomonowitz E. Accelerated phase-contrast MR imaging: comparison of k-t BLAST with SENSE and Doppler ultrasound for velocity and flow measurements in the aorta. J Magn Reson Imaging 2009; 29:817-24. [PMID: 19306404 DOI: 10.1002/jmri.21706] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To evaluate differences in velocity and flow measurements in the aorta between accelerated phase-contrast (PC) magnetic resonance imaging (MRI) using SENSE and k-t BLAST and in peak velocity to Doppler ultrasound. MATERIALS AND METHODS Two-dimensional PC-MRI perpendicular to the ascending and descending aorta was performed in 11 volunteers using SENSE (R = 2) and k-t BLAST (2-, 4-, 6-, and 8-fold). Peak velocity, mean velocity, and stroke volume of the accelerated PC-MRI experiments were correlated. Peak velocities were compared to Doppler ultrasound. RESULTS All acceleration techniques showed significant correlations for peak velocity with Doppler ultrasound. However, k-t BLAST 6 and 8 showed a significant underestimation. Strong correlations between SENSE and k-t BLAST were found for all three parameters. Significant differences in peak velocity were found between SENSE and all k-t BLAST experiments, but not for 2-fold k-t BLAST in the ascending aorta, and 2- and 4-fold k-t BLAST in the descending aorta. For mean velocity no significant differences were found. Stroke volume showed significant differences for all k-t BLAST experiments in the ascending and for 6- and 8-fold k-t BLAST in the descending aorta. CONCLUSION Peak velocity of accelerated PC-MRI correlated with CW Doppler measurements, but high k-t BLAST acceleration factors lead to a significant underestimation. SENSE with R = 2 and 2-fold k-t BLAST are most highly correlated in phase-contrast flow measurements.
Collapse
Affiliation(s)
- Andreas Stadlbauer
- MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Austria
| | | | | | | | | |
Collapse
|
12
|
Abstract
Modern rapid magnetic resonance (MR) imaging techniques have led to widespread use of the modality in cardiac imaging. Despite this progress, many MR studies suffer from image degradation due to involuntary motion during the acquisition. This review describes the type and extent of the motion of the heart due to the cardiac and respiratory cycles, which create image artifacts. Methods of eliminating or reducing the problems caused by the cardiac cycle are discussed, including electrocardiogram gating, subject-specific acquisition windows, and section tracking. Similarly, for respiratory motion of the heart, techniques such as breath holding, respiratory gating, section tracking, phase-encoding ordering, subject-specific translational models, and a range of new techniques are considered.
Collapse
Affiliation(s)
- Andrew D Scott
- Cardiovascular Magnetic Resonance Unit, the Royal Brompton Hospital, London, England.
| | | | | |
Collapse
|
13
|
Integrated physiological flow simulator and pulse sequence monitoring system for MRI. Med Biol Eng Comput 2008; 46:399-406. [DOI: 10.1007/s11517-008-0319-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
|
14
|
Baltes C, Hansen MS, Tsao J, Kozerke S, Rezavi R, Pedersen EM, Boesiger P. Determination of Peak Velocity in Stenotic Areas: Echocardiography versus k-t SENSE Accelerated MR Fourier Velocity Encoding. Radiology 2008; 246:249-57. [DOI: 10.1148/radiol.2453061366] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
15
|
Abstract
OBJECTIVE We present a two-part review about the use of MRI in patients with hypertrophic cardiomyopathy (HCM). This article, Part 1, focuses on the MRI appearances of HCM. CONCLUSION MRI has proven to be an important tool for the evaluation of patients suspected of having HCM because it can readily diagnose those with phenotypic expression of the disorder and can potentially identify the subset of patients at risk of sudden cardiac death.
Collapse
|
16
|
Grosse-Wortmann L, Al-Otay A, Goo HW, Macgowan CK, Coles JG, Benson LN, Redington AN, Yoo SJ. Anatomical and Functional Evaluation of Pulmonary Veins in Children by Magnetic Resonance Imaging. J Am Coll Cardiol 2007; 49:993-1002. [PMID: 17336724 DOI: 10.1016/j.jacc.2006.09.052] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 09/18/2006] [Accepted: 09/27/2006] [Indexed: 10/23/2022]
Abstract
Pulmonary vein pathologies often present a diagnostic challenge. Among the different imaging modalities used for the evaluation of pulmonary veins, magnetic resonance is the most comprehensive in assessing anatomy and pathophysiology at the same time. Bright blood cine sequences and contrast-enhanced magnetic resonance angiography outline the course and connections of the pulmonary veins. Phase-contrast velocity mapping measures flow patterns, velocities, and volumes throughout the pulmonary circulation. This paper reviews contemporary utilization of magnetic resonance in the evaluation of pulmonary venous abnormalities in children, based on our experience over the last 5 years and on that of other investigators. We summarize how magnetic resonance imaging enhances our understanding of pulmonary vein physiology and how it can influence the diagnostic approach to children and adults with a pulmonary venous pathology, and we discuss its limitations.
Collapse
Affiliation(s)
- Lars Grosse-Wortmann
- Section of Cardiac Imaging, Department of Diagnostic Imaging, The Hospital for Sick Children, The University of Toronto, Toronto, Canada
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Carvalho JLA, Nayak KS. Rapid quantitation of cardiovascular flow using slice-selective fourier velocity encoding with spiral readouts. Magn Reson Med 2007; 57:639-46. [PMID: 17390349 DOI: 10.1002/mrm.21196] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Accurate flow visualization and quantitation is important for the assessment of many cardiovascular conditions such as valvular stenosis and regurgitation. Phase contrast based methods experience partial volume artifacts when flow is highly localized, complex and/or turbulent. Fourier velocity encoding (FVE) avoids such problems by resolving the full velocity distribution within each voxel. This work proposes the use of slice selective FVE with spiral readouts to acquire fully localized velocity distributions in a short breath-hold. Scan-plane prescription is performed using classic protocols, and an automatic algorithm is used for in-plane localization of the flow. Time and spatially-resolved aortic valve velocity distributions with 26-msec temporal resolution and 25 cm/sec velocity resolution over a 600 cm/sec field-of-view were acquired in a 12-heartbeat breath-hold. In carotid studies, scan time was extended to achieve higher spatial resolution. The method was demonstrated in healthy volunteers and patients, and the results compared qualitatively well with Doppler ultrasound. Acquisition time could be reduced to 7 heartbeats (a 42% reduction) using partial Fourier reconstruction along the velocity dimension.
Collapse
Affiliation(s)
- Joao L A Carvalho
- Magnetic Resonance Engineering Laboratory, Department of Electrical Engineering-Systems, University of Southern California, Los Angeles, California, USA.
| | | |
Collapse
|