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Faragli A, Hüllebrand M, Berendsen AJ, Solà LT, Lo Muzio FP, Götze C, Tanacli R, Doeblin P, Stehning C, Schnackenburg B, Van der Vosse FN, Nagel E, Post H, Hennemuth A, Alogna A, Kelle S. Pulmonary 4D-flow MRI imaging in landrace pigs under rest and stress. Int J Cardiovasc Imaging 2024; 40:1511-1524. [PMID: 38819601 PMCID: PMC11258182 DOI: 10.1007/s10554-024-03132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 05/04/2024] [Indexed: 06/01/2024]
Abstract
4D-flow MRI is a promising technique for assessing vessel hemodynamics. However, its utilization is currently limited by the lack of reference values, particularly for pulmonary vessels. In this work, we have analysed flow and velocity in the pulmonary trunk (PT), left and right pulmonary arteries (LPA and RPA, respectively) in Landrace pigs at both rest and stress through the software MEVISFlow. Nine healthy Landrace pigs were acutely instrumented closed-chest and transported to the CMR facility for evaluation. After rest measurements, dobutamine was administered to achieve a 25% increase in heart rate compared to rest. 4D-flow MRI images have been analysed through MEVISFlow by two independent observers. Inter- and intra-observer reproducibility was quantified using intraclass correlation coefficient. A significant difference between rest and stress regarding flow and velocity in all the pulmonary vessels was observed. Mean flow increased 55% in PT, 75% in LPA and 40% in RPA. Mean peak velocity increased 55% in PT, 75% in LPA and 66% in RPA. A good-to-excellent reproducibility was observed in rest and stress for flow measurements in all three arteries. An excellent reproducibility for velocity was found in PT at rest and stress, a good one for LPA and RPA at rest, while poor reproducibility was found at stress. The current study showed that pulmonary flow and velocity assessed through 4D-flow MRI follow the physiological alterations during cardiac cycle and after stress induced by dobutamine. A clinical translation to assess pulmonary diseases with 4D-flow MRI under stress conditions needs investigation.
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Affiliation(s)
- A Faragli
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin, Berlin, Germany
| | - M Hüllebrand
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Berlin, Germany
| | - A J Berendsen
- Department of Biomedical Engineering, Cardiovascular Biomechanics Group, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - F P Lo Muzio
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - C Götze
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - R Tanacli
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin, Berlin, Germany
| | - P Doeblin
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin, Berlin, Germany
| | - C Stehning
- Clinical Science, Philips Healthcare, Hamburg, Germany
| | | | | | - E Nagel
- Institute of Experimental and Translational Cardiac Imaging, DZHK Centre for Cardiovascular Imaging, Goethe University Hospital Frankfurt, Frankfurt am Main, Germany
| | - H Post
- Department of Cardiology, Contilia Heart and Vessel Centre, St. Marien-Hospital Mülheim, Mülheim, Germany
| | - A Hennemuth
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Berlin, Germany
| | - A Alogna
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin, Berlin, Germany
| | - Sebastian Kelle
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Augustenburger Platz 1, 13353, Berlin, Germany.
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research) partner site Berlin, Berlin, Germany.
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Schuchardt FF, Krafft AJ, Miguel Telega L, Küchlin S, Lagrèze WA, Demerath T, Arnold P, Fung C, Kraus LM, Hennemuth A, Beck J, Urbach H, Weiller C, Harloff A. Interrelation Between Cerebrospinal Fluid Pressure, Intracranial Morphology and Venous Hemodynamics Studied by 4D Flow MRI. Clin Neuroradiol 2024; 34:391-401. [PMID: 38277058 PMCID: PMC11130051 DOI: 10.1007/s00062-023-01381-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024]
Abstract
PURPOSE To quantify the effects of CSF pressure alterations on intracranial venous morphology and hemodynamics in idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH) and assess reversibility when the underlying cause is resolved. METHODS We prospectively examined venous volume, intracranial venous blood flow and velocity, including optic nerve sheath diameter (ONSD) as a noninvasive surrogate of CSF pressure changes in 11 patients with IIH, 11 age-matched and sex-matched healthy controls and 9 SIH patients, before and after neurosurgical closure of spinal dural leaks. We applied multiparametric MRI including 4D flow MRI, time-of-flight (TOF) and T2-weighted half-Fourier acquisition single-shot turbo-spin echo (HASTE). RESULTS Sinus volume overlapped between groups at baseline but decreased after treatment of intracranial hypotension (p = 0.067) along with a significant increase of ONSD (p = 0.003). Blood flow in the middle and dorsal superior sagittal sinus was remarkably lower in patients with higher CSF pressure (i.e., IIH versus controls and SIH after CSF leak closure) but blood flow velocity was comparable cross-sectionally between groups and longitudinally in SIH. CONCLUSION We were able to demonstrate the interaction of CSF pressure, venous volumetry, venous hemodynamics and ONSD using multiparametric brain MRI. Closure of CSF leaks in SIH patients resulted in symptoms suggestive of increased intracranial pressure and caused a subsequent decrease of intracranial venous volume and of blood flow within the superior sagittal sinus while ONSD increased. In contrast, blood flow parameters from 4D flow MRI did not discriminate IIH, SIH and controls as hemodynamics at baseline overlapped at most vessel cross-sections.
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Affiliation(s)
- Florian F Schuchardt
- Department of Neurology and Neurophysiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
- Department of Neurology and Neurophysiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
| | - Axel J Krafft
- Medical Physics, Department of Radiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lidia Miguel Telega
- Department of Neurology and Neurophysiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian Küchlin
- Department of Neuro-ophthalmology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Wolf A Lagrèze
- Department of Neuro-ophthalmology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Theo Demerath
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg , Freiburg, Germany
| | - Philipp Arnold
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg , Freiburg, Germany
| | - Christian Fung
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Luisa M Kraus
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Institute for Cardiovascular Computer-assisted Medicine, Charité, Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany
| | - Jürgen Beck
- Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Horst Urbach
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg , Freiburg, Germany
| | - Cornelius Weiller
- Department of Neurology and Neurophysiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Bracamonte J, Truong U, Wilson J, Soares J. Correction of phase offset errors and quantification of background noise, signal-to-noise ratio, and encoded-displacement uncertainty on DENSE MRI for kinematics of the descending thoracic and abdominal aorta. Magn Reson Imaging 2024; 106:91-103. [PMID: 38092083 PMCID: PMC10842810 DOI: 10.1016/j.mri.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Displacement encoding with stimulated echoes (DENSE) MRI is a phase contrast technique that allows the encoding of tissue displacement into the phase of the magnetic resonance signal. Recent developments in this technique allow the imaging of relatively thin structures such as the aortic wall. Quantifying background noise associated to DENSE MRI is required to assess the uncertainty of derived displacement measurements and for the design and implementation of adequate noise-reduction techniques. Although noise and error management of cardiac DENSE MRI has been previously studied, developments for aortic applications are scarce. Herein, we evaluate the noise and uncertainty of DENSE MRI scans at three different locations along the descending aorta: the distal aortic arch (DAA), the descending thoracic aorta (DTA), and infrarenal abdominal aorta (IAA). Additionally, we analyze three datasets from in vitro validation experiments with polyvinyl alcohol phantoms. We implement and evaluate the effectiveness of an offset-error correction algorithm and noise filtering techniques on DENSE MRI for aortic motion applications. Our results show that the phase signal of pixels composing the static background was normally distributed, centered on average at 0.003 ± 0.02 rad and - 0.02 ± 0.024 rad for each phase directions, suggesting that background noise is random, isotropic, and DENSE MRI has little offset errors. However, background signal noise significantly increased with elapsed time of the cardiac cycle; and was spatially heterogeneous consistently increased towards the anterior space. Background noise showed no significant differences between the 3 aortic locations and the in vitro experiments. However, SNR depended on the displacement of the region of interest, in consequence it was found significantly larger at DAA (16.7 ± 8.5, p = 0.003) and DTA (15.4 ± 7.6, p = 0.008) than at the IAA (8.0 ± 4.1), but not significantly different than the SNR of in vitro experiments (8.0 ± 3.7), and had an overall average of 13 ± 7. The applied methods significantly reduced the offset error and effect of noise on the estimation of encoded displacements. Finally, this analysis suggests that the implemented DENSE MRI protocol is adequate to assess the motion of healthy human aortas. However, the relative effect of noise increased considerably on the analysis of an ageing or diseased aortas with impaired mobility, calling for further analyses on pathologically stiffened aortas.
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Affiliation(s)
- Johane Bracamonte
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Uyen Truong
- Department of Pediatrics, Division of Cardiology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - John Wilson
- Department of Biomedical Engineering and Pauley Heart Center, Virginia Commonwealth University, VA, USA
| | - Joao Soares
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, USA.
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Burkhardt BEU, Kellenberger CJ, Callaghan FM, Valsangiacomo Buechel ER, Geiger J. Flow evaluation software for four-dimensional flow MRI: a reliability and validation study. LA RADIOLOGIA MEDICA 2023; 128:1225-1235. [PMID: 37620674 PMCID: PMC10547653 DOI: 10.1007/s11547-023-01697-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/09/2023] [Indexed: 08/26/2023]
Abstract
PURPOSE Four-dimensional time-resolved phase-contrast cardiovascular magnetic resonance imaging (4D flow MRI) enables blood flow quantification in multiple vessels, which is crucial for patients with congenital heart disease (CHD). We investigated net flow volumes in the ascending aorta and pulmonary arteries by four different postprocessing software packages for 4D flow MRI in comparison with 2D cine phase-contrast measurements (2D PC). MATERIAL AND METHODS 4D flow and 2D PC datasets of 47 patients with biventricular CHD (median age 16, range 0.6-52 years) were acquired at 1.5 T. Net flow volumes in the ascending aorta, the main, right, and left pulmonary arteries were measured using four different postprocessing software applications and compared to offset-corrected 2D PC data. Reliability of 4D flow postprocessing software was assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC). Linear regression of internal flow controls was calculated. Interobserver reproducibility was evaluated in 25 patients. RESULTS Correlation and agreement of flow volumes were very good for all software compared to 2D PC (ICC ≥ 0.94; bias ≤ 5%). Internal controls were excellent for 2D PC (r ≥ 0.95, p < 0.001) and 4D flow (r ≥ 0.94, p < 0.001) without significant difference of correlation coefficients between methods. Interobserver reliability was good for all vendors (ICC ≥ 0.94, agreement bias < 8%). CONCLUSION Haemodynamic information from 4D flow in the large thoracic arteries assessed by four commercially available postprocessing applications matches routinely performed 2D PC values. Therefore, we consider 4D flow MRI-derived data ready for clinical use in patients with CHD.
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Affiliation(s)
- Barbara Elisabeth Ursula Burkhardt
- Paediatric Cardiology, Pediatric Heart Center, Department of Surgery, University Children's Hospital Zürich, Steinwiesstrasse 75, 8032, Zurich, Switzerland.
- Children's Research Center, University Children's Hospital Zürich, Zurich, Switzerland.
| | - Christian Johannes Kellenberger
- Department of Diagnostic Imaging, University Children's Hospital Zürich, Zurich, Switzerland
- Children's Research Center, University Children's Hospital Zürich, Zurich, Switzerland
| | - Fraser Maurice Callaghan
- Department of Diagnostic Imaging, University Children's Hospital Zürich, Zurich, Switzerland
- Children's Research Center, University Children's Hospital Zürich, Zurich, Switzerland
| | - Emanuela Regina Valsangiacomo Buechel
- Paediatric Cardiology, Pediatric Heart Center, Department of Surgery, University Children's Hospital Zürich, Steinwiesstrasse 75, 8032, Zurich, Switzerland
- Children's Research Center, University Children's Hospital Zürich, Zurich, Switzerland
| | - Julia Geiger
- Department of Diagnostic Imaging, University Children's Hospital Zürich, Zurich, Switzerland
- Children's Research Center, University Children's Hospital Zürich, Zurich, Switzerland
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5
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Azarnoosh J, Ghorbannia A, Ibrahim ESH, Jurkiewicz H, Kalvin L, LaDisa JF. Temporal evolution of mechanical stimuli from vascular remodeling in response to the severity and duration of aortic coarctation in a preclinical model. Sci Rep 2023; 13:8352. [PMID: 37221191 PMCID: PMC10205817 DOI: 10.1038/s41598-023-34400-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 04/28/2023] [Indexed: 05/25/2023] Open
Abstract
Coarctation of the aorta (CoA) is one of the most common congenital cardiovascular diseases. CoA patients frequently undergo surgical repair, but hypertension (HTN) is still common. The current treatment guideline has revealed irreversible changes in structure and function, yet revised severity guidelines have not been proposed. Our objective was to quantify temporal alterations in mechanical stimuli and changes in arterial geometry in response to the range of CoA severities and durations (i.e. age of treatment) seen clinically. Rabbits were exposed to CoA resulting in peak-to-peak blood pressure gradient (BPGpp) severities of ≤ 10, 10-20, and ≥ 20 mmHg for a duration of ~ 1, 3, or 20 weeks using permanent, dissolvable, and rapidly dissolvable sutures. Elastic moduli and thickness were estimated from imaging and longitudinal fluid-structure interaction (FSI) simulations were conducted at different ages using geometries and boundary conditions from experimentally measured data. Mechanical stimuli were characterized including blood flow velocity patterns, wall tension, and radial strain. Experimental results show vascular alternations including thickening and stiffening proximal to the coarctation with increasing severity and/or duration of CoA. FSI simulations indicate wall tension in the proximal region increases markedly with coarctation severity. Importantly, even mild CoA induced stimuli for remodeling that exceeds values seen in adulthood if not treated early and using a BPGpp lower than the current clinical threshold. The findings are aligned with observations from other species and provide some guidance for the values of mechanical stimuli that could be used to predict the likelihood of HTN in human patients with CoA.
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Affiliation(s)
- Jamasp Azarnoosh
- Department of Pediatrics - Section of Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA.
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Arash Ghorbannia
- Department of Pediatrics - Section of Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Herma Heart Institute, Children's Wisconsin, Milwaukee, WI, USA
| | - El-Sayed H Ibrahim
- Departments of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Hilda Jurkiewicz
- Department of Pediatrics - Section of Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Lindsey Kalvin
- Departments of Medicine - Division of Cardiovascular Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
| | - John F LaDisa
- Department of Pediatrics - Section of Cardiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, WI, USA
- Departments of Medicine - Division of Cardiovascular Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
- Departments of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Herma Heart Institute, Children's Wisconsin, Milwaukee, WI, USA
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6
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Mirakhorli F, Vahidi B, Pazouki M, Barmi PT. A Fluid-Structure Interaction Analysis of Blood Clot Motion in a Branch of Pulmonary Arteries. Cardiovasc Eng Technol 2023; 14:79-91. [PMID: 35788909 DOI: 10.1007/s13239-022-00632-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/09/2022] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Pulmonary embolism (PE) is one of the most prevalent diseases amid hospitalized patients taking many people's lives annually. This phenomenon, however, has not been investigated via numerical simulations. METHODS In this study, an image-based model of pulmonary arteries has been constructed from a 44-year-old man's computed tomography images. The fluid-structure interaction method was used to simulate the motion of the blood clot. In this regard, Navier-Stokes equations, as the governing equations, have been solved in an arbitrary Lagrangian-Eulerian (ALE) formulation. RESULTS According to our results, the velocity of visco-hyperelastic model of the emboli was relatively higher than the emboli with hyperelastic model, despite their similar behavioral pattern. The stresses on the clot were also investigated and showed that the blood clot continuously sustained stresses greater than 165 Pa over an about 0.01 s period, which can cause platelets to leak and make the clot grow or tear apart. CONCLUSIONS It could be concluded that in silico analysis of the cardiovascular diseases initiated from clot motion in blood flow is a valuable tool for a better understanding of these phenomena.
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Affiliation(s)
- Fateme Mirakhorli
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Bahman Vahidi
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran.
| | - Marzieh Pazouki
- Department of Pulmonary Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Pouria Talebi Barmi
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
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Oscanoa JA, Middione MJ, Syed AB, Sandino CM, Vasanawala SS, Ennis DB. Accelerated two-dimensional phase-contrast for cardiovascular MRI using deep learning-based reconstruction with complex difference estimation. Magn Reson Med 2022; 89:356-369. [PMID: 36093915 DOI: 10.1002/mrm.29441] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/16/2022] [Accepted: 08/11/2022] [Indexed: 11/10/2022]
Abstract
PURPOSE To develop and validate a deep learning-based reconstruction framework for highly accelerated two-dimensional (2D) phase contrast (PC-MRI) data with accurate and precise quantitative measurements. METHODS We propose a modified DL-ESPIRiT reconstruction framework for 2D PC-MRI, comprised of an unrolled neural network architecture with a Complex Difference estimation (CD-DL). CD-DL was trained on 155 fully sampled 2D PC-MRI pediatric clinical datasets. The fully sampled data ( n = 29 $$ n=29 $$ ) was retrospectively undersampled (6-11 × $$ \times $$ ) and reconstructed using CD-DL and a parallel imaging and compressed sensing method (PICS). Measurements of peak velocity and total flow were compared to determine the highest acceleration rate that provided accuracy and precision within ± 5 % $$ \pm 5\% $$ . Feasibility of CD-DL was demonstrated on prospectively undersampled datasets acquired in pediatric clinical patients ( n = 5 $$ n=5 $$ ) and compared to traditional parallel imaging (PI) and PICS. RESULTS The retrospective evaluation showed that 9 × $$ \times $$ accelerated 2D PC-MRI images reconstructed with CD-DL provided accuracy and precision (bias, [95 % $$ \% $$ confidence intervals]) within ± 5 % $$ \pm 5\% $$ . CD-DL showed higher accuracy and precision compared to PICS for measurements of peak velocity (2.8 % $$ \% $$ [ - 2 . 9 $$ -2.9 $$ , 4.5] vs. 3.9 % $$ \% $$ [ - 11 . 0 $$ -11.0 $$ , 4.9]) and total flow (1.8 % $$ \% $$ [ - 3 . 9 $$ -3.9 $$ , 3.4] vs. 2.9 % $$ \% $$ [ - 7 . 1 $$ -7.1 $$ , 6.9]). The prospective feasibility study showed that CD-DL provided higher accuracy and precision than PICS for measurements of peak velocity and total flow. CONCLUSION In a retrospective evaluation, CD-DL produced quantitative measurements of 2D PC-MRI peak velocity and total flow with ≤ 5 % $$ \le 5\% $$ error in both accuracy and precision for up to 9 × $$ \times $$ acceleration. Clinical feasibility was demonstrated using a prospective clinical deployment of our 8 × $$ \times $$ undersampled acquisition and CD-DL reconstruction in a cohort of pediatric patients.
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Affiliation(s)
- Julio A Oscanoa
- Department of Bioengineering, Stanford University, Stanford, California, USA.,Department of Radiology, Stanford University, Stanford, California, USA
| | | | - Ali B Syed
- Department of Radiology, Stanford University, Stanford, California, USA.,Cardiovascular Institute, Stanford University, Stanford, California, USA
| | - Christopher M Sandino
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | - Daniel B Ennis
- Department of Radiology, Stanford University, Stanford, California, USA.,Cardiovascular Institute, Stanford University, Stanford, California, USA
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8
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Fischer C, Wetzl J, Schaeffter T, Giese D. Fully automated background phase correction using M-estimate SAmple consensus (MSAC)-Application to 2D and 4D flow. Magn Reson Med 2022; 88:2709-2717. [PMID: 35916368 DOI: 10.1002/mrm.29363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/11/2022] [Accepted: 05/25/2022] [Indexed: 11/07/2022]
Abstract
PURPOSE Flow quantification by phase-contrast MRI is hampered by spatially varying background phase offsets. Correction performance by polynomial regression on stationary tissue may be affected by outliers such as wrap-around or constant flow. Therefore, we propose an alternative, M-estimate SAmple Consensus (MSAC) to reject outliers, and improve and fully automate background phase correction. METHODS The MSAC technique fits polynomials to randomly drawn small samples from the image. Over several trials, it aims to find the best consensus set of valid pixels by rejecting outliers to the fit and minimizing the residuals of the remaining pixels. The robustness of MSAC to its few parameters was investigated and verified using third-order polynomial correction fits on a total of 118 2D flow (97 with wrap-around) and 18 4D flow data sets (14 with wrap-around), acquired at 1.5 T and 3 T. Background phase was compared with standard stationary correction and phantom correction. Pulmonary/systemic flow ratios in 2D flow were derived, and exemplary 4D flow analysis was performed. RESULTS The MSAC technique is robust over a range of parameter choices, and a unique set of parameters is suitable for both 2D and 4D flow. In 2D flow, phase errors were significantly reduced by MSAC compared with stationary correction (p = 0.005), and stationary correction shows larger errors in pulmonary/systemic flow ratios compared with MSAC. In 4D flow, MSAC shows similar performance as stationary correction. CONCLUSIONS The MSAC method provides fully automated background phase correction to 2D and 4D flow data and shows improved robustness over stationary correction, especially with outliers present.
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Affiliation(s)
- Carola Fischer
- Department of Medical Imaging, Technical University of Berlin, Berlin, Germany.,Magnetic Resonance, Siemens Healthcare, Erlangen, Germany
| | - Jens Wetzl
- Magnetic Resonance, Siemens Healthcare, Erlangen, Germany
| | - Tobias Schaeffter
- Department of Medical Imaging, Technical University of Berlin, Berlin, Germany.,Biomedical Imaging, Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Berlin, Germany.,School of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare, Erlangen, Germany.,Institute of Radiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
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9
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Li J, Pei M, Bo B, Zhao X, Cang J, Fang F, Liang Z. Whole-brain mapping of mouse CSF flow via HEAP-METRIC phase-contrast MRI. Magn Reson Med 2022; 87:2851-2861. [PMID: 35107833 PMCID: PMC9305925 DOI: 10.1002/mrm.29179] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/06/2022] [Accepted: 01/10/2022] [Indexed: 11/17/2022]
Abstract
Purpose CSF plays important roles in clearing brain waste and homeostasis. However, mapping whole‐brain CSF flow in the rodents is difficult, primarily due to its assumed very low velocity. Therefore, we aimed to develop a novel phase‐contrast MRI method to map whole‐brain CSF flow in the mouse brain. Methods A novel generalized Hadamard encoding–based multi‐band scheme (dubbed HEAP‐METRIC, Hadamard Encoding APproach of Multi‐band Excitation for short TR Imaging aCcelerating) using complex Hadamard matrix was developed and incorporated into conventional phase contrast (PC)‐MRI to significantly increase SNR. Results Slow flow phantom imaging validated HEAP‐METRIC PC‐MRI’s ability to achieve fast and accurate mapping of slow flow velocities (~102 µm/s). With the SNR gain afforded by HEAP‐METRIC scheme, high‐resolution (0.08 × 0.08 mm in‐plane resolution and 36 0.4 mm slices) PC‐MRI was completed in 21 min for whole‐brain CSF flow mapping in the mouse. Using this novel method, we provide the first report of whole‐brain CSF flow in the awake mouse brain with an average flow velocity of ~200 µm/s. Furthermore, HEAP‐METRIC PC‐MRI revealed CSF flow was reduced by isoflurane anesthesia, accompanied by reduction of glymphatic function as measured by dynamic contrast‐enhanced MRI. Conclusion We developed and validated a generalized HEAP‐METRIC PC‐MRI for mapping low velocity flow. With this method, we have achieved the first whole‐brain mapping of awake mouse CSF flow and have further revealed that anesthesia reduces CSF flow velocity.
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Affiliation(s)
- Juchen Li
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.,Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Mengchao Pei
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Binshi Bo
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Xinxin Zhao
- Department of Radiology, Shanghai Cancer Institute, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Jing Cang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Fang Fang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Zhifeng Liang
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, People's Republic of China
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10
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Yavuz Ilik S, Otani T, Yamada S, Watanabe Y, Wada S. A subject-specific assessment of measurement errors and their correction in cerebrospinal fluid velocity maps using 4D flow MRI. Magn Reson Med 2021; 87:2412-2423. [PMID: 34866235 DOI: 10.1002/mrm.29111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE Phase-contrast MRI (PC-MRI) of cerebrospinal fluid (CSF) velocity is used to evaluate the characteristics of intracranial diseases, such as normal-pressure hydrocephalus (NPH). Nevertheless, PC-MRI has several potential error sources, with eddy-current-based phase offset error being non-negligible in CSF measurement. In this study, we assess the measurement error of CSF velocity maps obtained using 4D flow MRI and evaluate correction methods. METHODS CSF velocity maps of 10 patients with NPH were acquired using 4D flow MRI (velocity-encoding = 5 cm/s). Distributed phase offset error was estimated for a whole 3D background field by polynomial fitting using robust regression analysis. This estimated phase offset error was then used to correct the CSF velocity maps. The estimated error profiles were compared with those obtained using an existing 2D correction approach involving local background information near the region of interest. RESULTS The residual standard error of the polynomial fitting against the phase offset error extracted from the measured velocities was within 0.2 cm/s. The spatial dependencies of the phase offset errors showed similar tendencies in all cases, but sufficient differences in these values were found to indicate requirement of velocity correction. Differences of the estimated errors among other correction approaches were in the order of 10-2 cm/s, and the estimated errors were in good agreement with those obtained using existing approaches. CONCLUSION Our method is capable of estimating the measurement error of CSF velocity maps obtained from 4D flow MRI and provides quantitatively reasonable characteristics for the main CSF profile in the cerebral aqueduct in patients with NPH.
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Affiliation(s)
- Selin Yavuz Ilik
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Tomohiro Otani
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Shigeki Yamada
- Department of Neurosurgery, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Yoshiyuki Watanabe
- Department of Radiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
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11
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Lagerstrand KM, Truedsson F, Gao SA, Johansson A, Bech-Hanssen O, Polte CL, Johnsson ÅA. Importance of through-plane heart motion correction for the assessment of aortic regurgitation severity using phase contrast magnetic resonance imaging. Magn Reson Imaging 2021; 84:69-75. [PMID: 34560232 DOI: 10.1016/j.mri.2021.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 09/11/2021] [Accepted: 09/16/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To elucidate the influence of through-plane heart motion on the assessment of aortic regurgitation (AR) severity using phase contrast magnetic resonance imaging (PC-MRI). APPROACH A patient cohort with chronic AR (n = 34) was examined with PC-MRI. The regurgitant volume (RVol) and fraction (RFrac) were extracted from the PC-MRI data before and after through-plane heart motion correction and was then used for assessment of AR severity. RESULTS The flow volume errors were strongly correlated to aortic diameter (R = 0.80, p < 0.001) with median (IQR 25%;75%): 16 (14; 17) ml for diameter>40mm, compared with 9 (7; 10) ml for normal aortic size (p < 0.001). RVol and RFrac were underestimated (uncorrected:64 ± 37 ml and 39 ± 17%; corrected:76 ± 37 ml and 44 ± 15%; p < 0.001) and ~ 20% of the patients received lower severity grade without correction. CONCLUSION Through-plane heart motion introduces relevant flow volume errors, especially in patients with aortic dilatation that may result in underestimation of the severity grade in patients with chronic AR.
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Affiliation(s)
- Kerstin M Lagerstrand
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Frida Truedsson
- Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Sinsia A Gao
- Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Alexander Johansson
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Odd Bech-Hanssen
- Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Christian L Polte
- Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Åse A Johnsson
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Radiology, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Sweden
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12
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Gaidzik F, Pravdivtseva M, Larsen N, Jansen O, Hövener JB, Berg P. Luminal enhancement in intracranial aneurysms: fact or feature?-A quantitative multimodal flow analysis. Int J Comput Assist Radiol Surg 2021; 16:1999-2008. [PMID: 34519953 PMCID: PMC8589743 DOI: 10.1007/s11548-021-02486-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 08/17/2021] [Indexed: 11/04/2022]
Abstract
Purpose Intracranial aneurysm (IA) wall enhancement on post-contrast vessel wall magnetic resonance imaging (VW-MRI) is assumed to be a biomarker for vessel wall inflammation and aneurysm instability. However, the exact factors contributing to enhancement are not yet clarified. This study investigates the relationship between luminal enhancement and intra-aneurysmal flow behaviour to assess the suitability of VW-MRI as a surrogate method for determining quantitative and qualitative flow behaviour in the aneurysm sac. Methods VW-MRI signal is measured in the lumen of three patient-specific IA flow models and compared with the intra-aneurysmal flow fields obtained using phase-contrast magnetic resonance imaging (PC-MRI) and computational fluid dynamics (CFD). The IA flow models were supplied with two different time-varying flow regimes. Results Overall, the velocity fields acquired using PC-MRI or CFD were in good agreement with the VW-MRI enhancement patterns. Generally, the regions with slow-flowing blood show higher VW-MRI signal intensities, whereas high flow leads to a suppression of the signal. For all aneurysm models, a signal value above three was associated with velocity values below three cm/s. Conclusion Regions with lower enhancements have been correlated with the slow and high flow at the same time. Thus, further factors like flow complexity and stability can contribute to flow suppression in addition to the flow magnitude. Nevertheless, VW-MRI can qualitatively assess intra-aneurysmal flow phenomena and estimate the velocity range present in the corresponding region.
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Affiliation(s)
- Franziska Gaidzik
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke University, University of Magdeburg, Forschungscampus STIMULATE, Universitätsplatz 3, 39106, Magdeburg, Germany.
| | - Mariya Pravdivtseva
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, Kiel, Germany.,Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Naomi Larsen
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Olav Jansen
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, Kiel, Germany.,Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Philipp Berg
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke University, University of Magdeburg, Forschungscampus STIMULATE, Universitätsplatz 3, 39106, Magdeburg, Germany
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13
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van Hespen KM, Kuijf HJ, Hendrikse J, Luijten PR, Zwanenburg JJM. Blood Flow Velocity Pulsatility and Arterial Diameter Pulsatility Measurements of the Intracranial Arteries Using 4D PC-MRI. Neuroinformatics 2021; 20:317-326. [PMID: 34019208 PMCID: PMC9546978 DOI: 10.1007/s12021-021-09526-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2021] [Indexed: 10/28/2022]
Abstract
4D phase contrast magnetic resonance imaging (PC-MRI) allows for the visualization and quantification of the cerebral blood flow. A drawback of software that is used to quantify the cerebral blood flow is that it oftentimes assumes a static arterial luminal area over the cardiac cycle. Quantifying the lumen area pulsatility index (aPI), i.e. the change in lumen area due to an increase in distending pressure over the cardiac cycle, can provide insight in the stiffness of the arteries. Arterial stiffness has received increased attention as a predictor in the development of cerebrovascular disease. In this study, we introduce software that allows for measurement of the aPI as well as the blood flow velocity pulsatility index (vPI) from 4D PC-MRI. The internal carotid arteries of seven volunteers were imaged using 7 T MRI. The aPI and vPI measurements from 4D PC-MRI were validated against measurements from 2D PC-MRI at two levels of the internal carotid arteries (C3 and C7). The aPI and vPI computed from 4D PC-MRI were comparable to those measured from 2D PC-MRI (aPI: mean difference: 0.03 (limits of agreement: -0.14 - 0.23); vPI: 0.03 (-0.17-0.23)). The measured blood flow rate for the C3 and C7 segments was similar, indicating that our proposed software correctly captures the variation in arterial lumen area and blood flow velocity that exists along the distal end of the carotid artery. Our software may potentially aid in identifying changes in arterial stiffness of the intracranial arteries caused by pathological changes to the vessel wall.
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Affiliation(s)
| | - Hugo J Kuijf
- Image Sciences Institute, UMC Utrecht, Utrecht, The Netherlands
| | | | - Peter R Luijten
- Department of Radiology, UMC Utrecht, Utrecht, The Netherlands
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14
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Kroeger JR, Pavesio FC, Mörsdorf R, Weiss K, Bunck AC, Baeßler B, Maintz D, Giese D. Velocity quantification in 44 healthy volunteers using accelerated multi-VENC 4D flow CMR. Eur J Radiol 2021; 137:109570. [PMID: 33596498 DOI: 10.1016/j.ejrad.2021.109570] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/25/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND To evaluate the feasibility of a k-t accelerated multi-VENC 4D phase contrast flow MRI acquisition of the main heart-surrounding vessels, its benefits over a traditional single-VENC acquisition and to present reference flow and velocity values in a large cohort of volunteers. METHODS 44 healthy volunteers were examined on a 3 T MRI scanner (Ingenia, Philips, Best, The Netherlands). 4D flow measurements were obtained with a FOV including the aorta and the pulmonary arteries. VENC values were set to 40, 100 and 200 cm/s and unfolded based on an MRI signal model. Unfolded multi-VENC data was compared to the single-VENC with VENC 200 cm/s. Flow and velocity quantification was performed in several regions of interest (ROI) placed in the ascending aorta and in the main pulmonary artery. Conservation of mass analysis was performed for single- and multi-VENC datasets. Values for mean and maximal flow velocity and stroke volume were calculated and compared to the literature. RESULTS Mean scan time was 13.8 ± 4 min. Differences between stroke volumes between the ascending aorta and the main pulmonary artery were significantly lower in multi-VENC datasets compared to single-VENC datasets (9.6 ± 7.8 mL vs. 25.4 ± 26.4 mL, p < 0.001). This was also true for differences in stroke volume between up- and downstream ROIs in the ascending aorta and pulmonary artery. Values for mean and maximal velocities and stroke volume were in-line with previous studies. To highlight potential clinical applications two exemplary 4D flow measurements in patients with different pathologies are shown and compared to single-VENC datasets. CONCLUSIONS k-t accelerated multi-VENC 4D phase contrast flow MRI acquisition of the great vessels is feasible in a clinically acceptable scan duration. It offers improvements over traditional single-VENC 4D flow, expectedly being valuable when vessels with different flow velocities or complex flow phenomena are evaluated.
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Affiliation(s)
- Jan Robert Kroeger
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Department of Radiology, Neuroradiology and Nuclear Medicine, Johannes Wesling University Hospital, Ruhr University Bochum, Germany.
| | - Francesca Claudia Pavesio
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Richard Mörsdorf
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Kilian Weiss
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Philips GmbH, Hamburg, Germany.
| | - Alexander Christian Bunck
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Bettina Baeßler
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland.
| | - David Maintz
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Daniel Giese
- Department of Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
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15
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Bertelsen L, Vejlstrup N, Andreasen L, Olesen MS, Svendsen JH. Cardiac magnetic resonance systematically overestimates mitral regurgitations by the indirect method. Open Heart 2020; 7:openhrt-2020-001323. [PMID: 32675299 PMCID: PMC7368492 DOI: 10.1136/openhrt-2020-001323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/03/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022] Open
Abstract
Objective Cardiac MRI is quickly emerging as the gold standard for assessment of mitral regurgitation, most commonly with the indirect method subtracting forward flow in aorta from volumetric segmentation of the left ventricle. We aimed to investigate how aortic flow measurements with increasing distance from the aortic valve affect calculated mitral regurgitations and whether measurements were influenced by breath-hold regimen. Methods Free-breathing and breath-hold phase contrast flows were measured in aorta at valve level, sinotubular (ST) junction, mid-ascending aorta and in the pulmonary trunk. Flow measurements were pairwise compared, and subsequently, after exclusion of patients with visible mitral and tricuspid regurgitations for left-sided and right-sided comparisons, respectively, flow-measured stroke volumes were compared with ventricular volumetric segmentations. Results Thirty-nine participants without arrhythmias or structural abnormalities of the large vessels were included. Stroke volumes measured with free-breathing and breath-hold flow decreased equally with increasing distance to the aortic valves (breath-hold flow: aortic valve 105.6±20.8 mL, ST junction 101.5±20.7 mL, mid-ascending aorta 98.1±21.5 mL). After exclusion of atrioventricular regurgitations, stroke volumes determined by volumetric measurements were higher compared with values determined by flow measurements, corresponding to ‘false’ atrioventricular regurgitations of 8.0%±5.8% with flow measured at valve level, 11.6%±5.2% at the ST junction and 15.3%±5.0% at the mid-ascending aorta. Conclusions Stroke volumes determined by flow decrease throughout the proximal aorta and are systematically lower than volumetrically measured stroke volumes. The indirect method systematically overestimates mitral regurgitations, especially with increasing distance from the aortic valves.
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Affiliation(s)
- Litten Bertelsen
- Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Niels Vejlstrup
- Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Laura Andreasen
- Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Salling Olesen
- Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Hastrup Svendsen
- Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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16
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Lagerstrand KM, Svensson F, Polte CL, Bech-Hanssen O, Starck G, Chadorowski A, Johnsson ÅA. Reliable phase-contrast flow volume magnetic resonance measurements are feasible without adjustment of the velocity encoding parameter. J Med Imaging (Bellingham) 2020; 7:063502. [PMID: 33313339 DOI: 10.1117/1.jmi.7.6.063502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 11/23/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose: To show that adjustment of velocity encoding (VENC) for phase-contrast (PC) flow volume measurements is not necessary in modern MR scanners with effective background velocity offset corrections. Approach: The independence on VENC was demonstrated theoretically, but also experimentally on dedicated phantoms and on patients with chronic aortic regurgitation ( n = 17 ) and one healthy volunteer. All PC measurements were performed using a modern MR scanner, where the pre-emphasis circuit but also a subsequent post-processing filter were used for effective correction of background velocity offset errors. Results: The VENC level strongly affected the velocity noise level in the PC images and, hence, the estimated peak flow velocity. However, neither the regurgitant blood flow volume nor the mean flow velocity displayed any clinically relevant dependency on the VENC level. Also, the background velocity offset was shown to be close to zero ( < 0.6 cm / s ) for a VENC range of 150 to 500 cm / s , adding no significant errors to the PC flow volume measurement. Conclusions: Our study shows that reliable PC flow volume measurements are feasible without adjustment of the VENC parameter. Without the need for VENC adjustments, the scan time can be reduced for the benefit of the patient.
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Affiliation(s)
- Kerstin M Lagerstrand
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Frida Svensson
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Christian L Polte
- The Sahlgrenska Academy, University of Gothenburg, Institute of Medicine, Sweden.,Sahlgrenska University Hospital, Department of Clinical Physiology, Gothenburg, Sweden
| | - Odd Bech-Hanssen
- The Sahlgrenska Academy, University of Gothenburg, Institute of Medicine, Sweden.,Sahlgrenska University Hospital, Department of Clinical Physiology, Gothenburg, Sweden
| | - Göran Starck
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Artur Chadorowski
- Chalmers University of Technology, Department of Electrical Engineering, Gothenburg, Sweden
| | - Åse A Johnsson
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Radiology, Gothenburg, Sweden
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17
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Fathi MF, Perez-Raya I, Baghaie A, Berg P, Janiga G, Arzani A, D'Souza RM. Super-resolution and denoising of 4D-Flow MRI using physics-Informed deep neural nets. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 197:105729. [PMID: 33007592 DOI: 10.1016/j.cmpb.2020.105729] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/23/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Time resolved three-dimensional phase contrast magnetic resonance imaging (4D-Flow MRI) has been used to non-invasively measure blood velocities in the human vascular system. However, issues such as low spatio-temporal resolution, acquisition noise, velocity aliasing, and phase-offset artifacts have hampered its clinical application. In this research, we developed a purely data-driven method for super-resolution and denoising of 4D-Flow MRI. METHODS The flow velocities, pressure, and the MRI image magnitude are modeled as a patient-specific deep neural net (DNN). For training, 4D-Flow MRI images in the complex Cartesian space are used to impose data-fidelity. Physics of fluid flow is imposed through regularization. Creative loss function terms have been introduced to handle noise and super-resolution. The trained patient-specific DNN can be sampled to generate noise-free high-resolution flow images. The proposed method has been implemented using the TensorFlow DNN library and tested on numerical phantoms and validated in-vitro using high-resolution particle image velocitmetry (PIV) and 4D-Flow MRI experiments on transparent models subjected to pulsatile flow conditions. RESULTS In case of numerical phantoms, we were able to increase spatial resolution by a factor of 100 and temporal resolution by a factor of 5 compared to the simulated 4D-Flow MRI. There is an order of magnitude reduction of velocity normalized root mean square error (vNRMSE). In case of the in-vitro validation tests with PIV as reference, there is similar improvement in spatio-temporal resolution. Although the vNRMSE is reduced by 50%, the method is unable to negate a systematic bias with respect to the reference PIV that is introduced by the 4D-Flow MRI measurement. CONCLUSIONS This work has demonstrated the feasibility of using the readily available machinery of deep learning to enhance 4D-Flow MRI using a purely data-driven method. Unlike current state-of-the-art methods, the proposed method is agnostic to geometry and boundary conditions and therefore eliminates the need for tedious tasks such as accurate image segmentation for geometry, image registration, and estimation of boundary flow conditions. Arbitrary regions of interest can be selected for processing. This work will lead to user-friendly analysis tools that will enable quantitative hemodynamic analysis of vascular diseases in a clinical setting.
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Affiliation(s)
- Mojtaba F Fathi
- Dept. of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Isaac Perez-Raya
- Dept. of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Ahmadreza Baghaie
- Dept. of Electrical and Computer Engineering, New York Institute of Technology, Long Island, NY, USA
| | - Philipp Berg
- Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg, Germany; Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Gabor Janiga
- Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg, Germany; Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Amirhossein Arzani
- Dept. of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA
| | - Roshan M D'Souza
- Dept. of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
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18
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Minderhoud SCS, van der Velde N, Wentzel JJ, van der Geest RJ, Attrach M, Wielopolski PA, Budde RPJ, Helbing WA, Roos-Hesselink JW, Hirsch A. The clinical impact of phase offset errors and different correction methods in cardiovascular magnetic resonance phase contrast imaging: a multi-scanner study. J Cardiovasc Magn Reson 2020; 22:68. [PMID: 32938483 PMCID: PMC7495876 DOI: 10.1186/s12968-020-00659-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/06/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) phase contrast (PC) flow measurements suffer from phase offset errors. Background subtraction based on stationary phantom measurements can most reliably be used to overcome this inaccuracy. Stationary tissue correction is an alternative and does not require additional phantom scanning. The aim of this study was 1) to compare measurements with and without stationary tissue correction to phantom corrected measurements on different GE Healthcare CMR scanners using different software packages and 2) to evaluate the clinical implications of these methods. METHODS CMR PC imaging of both the aortic and pulmonary artery flow was performed in patients on three different 1.5 T CMR scanners (GE Healthcare) using identical scan parameters. Uncorrected, first, second and third order stationary tissue corrected flow measurement were compared to phantom corrected flow measurements, our reference method, using Medis QFlow, Circle cvi42 and MASS software. The optimal (optimized) stationary tissue order was determined per scanner and software program. Velocity offsets, net flow, clinically significant difference (deviation > 10% net flow), and regurgitation severity were assessed. RESULTS Data from 175 patients (28 (17-38) years) were included, of which 84% had congenital heart disease. First, second and third order and optimized stationary tissue correction did not improve the velocity offsets and net flow measurements. Uncorrected measurements resulted in the least clinically significant differences in net flow compared to phantom corrected data. Optimized stationary tissue correction per scanner and software program resulted in net flow differences (> 10%) in 19% (MASS) and 30% (Circle cvi42) of all measurements compared to 18% (MASS) and 23% (Circle cvi42) with no correction. Compared to phantom correction, regurgitation reclassification was the least common using uncorrected data. One CMR scanner performed worse and significant net flow differences of > 10% were present both with and without stationary tissue correction in more than 30% of all measurements. CONCLUSION Phase offset errors had a significant impact on net flow quantification, regurgitation assessment and varied greatly between CMR scanners. Background phase correction using stationary tissue correction worsened accuracy compared to no correction on three GE Healthcare CMR scanners. Therefore, careful assessment of phase offset errors at each individual scanner is essential to determine whether routine use of phantom correction is necessary. TRIAL REGISTRATION Observational Study.
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Affiliation(s)
- Savine C. S. Minderhoud
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Nikki van der Velde
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jolanda J. Wentzel
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
| | - Rob J. van der Geest
- Department of Radiology, Division of Image Processing, Leiden University Medical Center, Leiden, The Netherlands
| | - Mohammed Attrach
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Piotr A. Wielopolski
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Ricardo P. J. Budde
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Willem A. Helbing
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Pediatric Cardiology, Department of Pediatrics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jolien W. Roos-Hesselink
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
| | - Alexander Hirsch
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Ajala A, Zhang J, Pednekar A, Buko E, Wang L, Cheong BY, Hor PH, Muthupillai R. Mitral Valve Flow and Myocardial Motion Assessed with Dual-Echo Dual-Velocity Cardiac MRI. Radiol Cardiothorac Imaging 2020; 2:e190126. [PMID: 33778578 DOI: 10.1148/ryct.2020190126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 02/11/2020] [Accepted: 02/18/2020] [Indexed: 12/31/2022]
Abstract
Purpose To develop a dual-echo phase-contrast (DEPC) MRI approach with which each echo is acquired by using a different velocity sensitivity within one repetition time (TR) and demonstrate the feasibility of this approach to measure transmitral blood flow (E) and myocardial tissue (E m) velocities. Materials and Methods The flow across tubes of known diameter was measured by using the proposed DEPC method and compared with flowmeter measurements and theoretic predictions. Then, with both the DEPC MRI sequence and the conventional single-echo phase-contrast (SEPC) MRI sequence, E, E m, and E/E m were measured in six healthy volunteers (mean age, 49 years ± 13 [standard deviation]) and eight patients (mean age, 54 years ± 15) being evaluated for cardiac disease. Differences between the DEPC and conventional SEPC MRI methods were assessed by percent error, Pearson correlation, and Bland-Altman analyses. Results Velocities measured in vitro and in vivo by using the SEPC and DEPC MRI approaches were well correlated (r 2 > 0.97), with negligible bias (<0.5 cm/sec) and comparable velocity-to-noise ratios. Imaging times were approximately 19% shorter with the DEPC method (TR, 5.7 msec) than with the SEPC method (TR, 2.8 msec ± 4.2) (P < .05). Conclusion The proposed DEPC method was sensitive to two velocity regimes within a single TR, resulting in a shorter imaging time compared with the imaging time in conventional SEPC MRI. Preliminary human study results suggest the feasibility of using this approach to estimate E/E m.Supplemental material is available for this article.© RSNA, 2020.
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Affiliation(s)
- Afis Ajala
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Jiming Zhang
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Amol Pednekar
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Erick Buko
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Luning Wang
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Benjamin Y Cheong
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Pei-Herng Hor
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
| | - Raja Muthupillai
- Department of Physics (A.A., E.B., P.H.H., R.M.) and Texas Center for Superconductivity (P.H.H.), University of Houston, Houston, Tex; Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.Z.); Department of Diagnostic and Interventional Radiology, CHI-St Luke's Health-Baylor St Luke's Medical Center, 6720 Bertner Ave, MC-2-270, Houston, TX 77030 (E.B., B.Y.C., R.M.); Department of Radiology, Texas Children's Hospital, Houston, Tex (A.P., L.W.); and Texas Heart Institute, Houston, Tex (B.Y.C., R.M.)
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Paul EA, Solana AB, Duong J, Shah AM, Lai WW, Tan ET, Hardy CJ, Chelliah A. Evaluation of self-calibrated non-linear phase-contrast correction in pediatric and congenital cardiovascular magnetic resonance imaging. Pediatr Radiol 2020; 50:656-663. [PMID: 32047987 DOI: 10.1007/s00247-020-04623-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/10/2019] [Accepted: 01/21/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND The need for background error correction in phase-contrast flow analysis has historically posed a challenge in cardiac magnetic resonance (MR) imaging. While previous studies have shown that phantom correction improves flow measurements, it impedes scanner workflow. OBJECTIVE To evaluate the efficacy of self-calibrated non-linear phase-contrast correction on flows in pediatric and congenital cardiac MR compared to phantom correction as the standard. MATERIALS AND METHODS We retrospectively identified children who had great-vessel phase-contrast and static phantom sequences acquired between January 2015 and June 2015. We applied a novel correction method to each phase-contrast sequence post hoc. Uncorrected, non-linear, and phantom-corrected flows were compared using intraclass correlation. We used paired t-tests to compare how closely non-linear and uncorrected flows approximated phantom-corrected flows. In children without intra- or extracardiac shunts or significant semilunar valvular regurgitation, we used paired t-tests to compare how closely the uncorrected pulmonary-to-systemic flow ratio (Qp:Qs) and non-linear Qp:Qs approximated phantom-corrected Qp:Qs. RESULTS We included 211 diagnostic-quality phase-contrast sequences (93 aorta, 74 main pulmonary artery [MPA], 21 left pulmonary artery [LPA], 23 right pulmonary artery [RPA]) from 108 children (median age 15 years, interquartile range 11-18 years). Intraclass correlation showed strong agreement between non-linear and phantom-corrected flow measurements but also between uncorrected and phantom-corrected flow measurements. Non-linear flow measurements did not more closely approximate phantom-corrected measurements than did uncorrected measurements for any vessel. In 39 children without significant shunting or regurgitation, mean non-linear Qp:Qs (1.07; 95% confidence interval [CI] = 1.01, 1.13) was no closer than mean uncorrected Qp:Qs (1.06; 95% CI = 1.00, 1.13) to mean phantom-corrected Qp:Qs (1.02; 95% CI = 0.98, 1.06). CONCLUSION Despite strong agreement between self-calibrated non-linear and phantom correction, cardiac flows and shunt calculations with non-linear correction were no closer to phantom-corrected measurements than those without background correction. However, phantom-corrected flows also demonstrated minimal differences from uncorrected flows. These findings suggest that in the current era, more accurate phase-contrast flow measurements might limit the need for background correction. Further investigation of the clinical impact and optimal methods of background correction in the pediatric and congenital cardiac population is needed.
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Affiliation(s)
- Erin A Paul
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA.
| | | | - Jimmy Duong
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY, USA
| | - Amee M Shah
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA
| | - Wyman W Lai
- Department of Pediatric Cardiology, Children's Hospital of Orange County, Orange, CA, USA
| | - Ek T Tan
- GE Global Research, Niskayuna, NY, USA
| | | | - Anjali Chelliah
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA
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Stationary tissue background correction increases the precision of clinical evaluation of intra-cardiac shunts by cardiovascular magnetic resonance. Sci Rep 2020; 10:5053. [PMID: 32193468 PMCID: PMC7081189 DOI: 10.1038/s41598-020-61812-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/02/2020] [Indexed: 11/18/2022] Open
Abstract
We aimed to evaluate the clinical utility of stationary tissue background phase correction for affecting precision in the measurement of Qp/Qs by cardiovascular magnetic resonance (CMR). We enrolled consecutive patients (n = 91) referred for CMR at 1.5T without suspicion of cardiac shunt, and patients (n = 10) with verified cardiac shunts in this retrospective study. All patients underwent phase contrast flow quantification in the ascending aorta and pulmonary trunk. Flow was quantified using two semi-automatic software platforms (SyngoVia VA30, Vendor 1; Segment 2.0R4534, Vendor 2). Measurements were performed both uncorrected and corrected for linear (Vendor 1 and Vendor 2) or quadratic (Vendor 2) background phase. The proportion of patients outside the normal range of Qp/Qs was compared using the McNemar’s test. Compared to uncorrected measurements, there were fewer patients with a Qp/Qs outside the normal range following linear correction using Vendor 1 (10% vs 18%, p < 0.001), and Vendor 2 (10% vs 18%, p < 0.001), and following quadratic correction using Vendor 2 (7% vs 18%, p < 0.001). No patient with known shunt was reclassified as normal following stationary background correction. Therefore, we conclude that stationary tissue background correction reduces the number of patients with a Qp/Qs ratio outside the normal range in a consecutive clinical population, while simultaneously not reclassifying any patient with known cardiac shunts as having a normal Qp/Qs. Stationary tissue background correction may be used in clinical patients to increase diagnostic precision.
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Abstract
Mitral regurgitation (MR) is a common valvular heart disease and is the second most frequent indication for heart valve surgery in Western countries. Echocardiography is the recommended first-line test for the assessment of valvular heart disease, but cardiovascular magnetic resonance imaging (CMR) provides complementary information, especially for assessing MR severity and to plan the timing of intervention. As new CMR techniques for the assessment of MR have arisen, standardizing CMR protocols for research and clinical studies has become important in order to optimize diagnostic utility and support the wider use of CMR for the clinical assessment of MR. In this Consensus Statement, we provide a detailed description of the current evidence on the use of CMR for MR assessment, highlight its current clinical utility, and recommend a standardized CMR protocol and report for MR assessment. In this Consensus Statement, Garg and colleagues describe the current evidence on the use of cardiovascular magnetic resonance imaging for the assessment of mitral regurgitation, highlight its current clinical utility, and recommend a standardized imaging protocol and report.
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Callaghan FM, Burkhardt B, Geiger J, Valsangiacomo Buechel ER, Kellenberger CJ. Flow quantification dependency on background phase correction techniques in 4D‐flow MRI. Magn Reson Med 2019; 83:2264-2275. [DOI: 10.1002/mrm.28085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/09/2019] [Accepted: 10/24/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Fraser M. Callaghan
- Center for MR Research University Children's Hospital Zurich Switzerland
- Children's Research Center University Children's Hospital Zurich Switzerland
| | - Barbara Burkhardt
- Children's Research Center University Children's Hospital Zurich Switzerland
- Division of Pediatric Cardiology University Children's Hospital Zurich Switzerland
| | - Julia Geiger
- Children's Research Center University Children's Hospital Zurich Switzerland
- Department of Diagnostic Imaging University Children's Hospital Zurich Switzerland
| | - Emanuela R. Valsangiacomo Buechel
- Children's Research Center University Children's Hospital Zurich Switzerland
- Division of Pediatric Cardiology University Children's Hospital Zurich Switzerland
| | - Christian J. Kellenberger
- Children's Research Center University Children's Hospital Zurich Switzerland
- Department of Diagnostic Imaging University Children's Hospital Zurich Switzerland
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Sieren MM, Berlin C, Oechtering TH, Hunold P, Drömann D, Barkhausen J, Frydrychowicz A. Comparison of 4D Flow MRI to 2D Flow MRI in the pulmonary arteries in healthy volunteers and patients with pulmonary hypertension. PLoS One 2019; 14:e0224121. [PMID: 31648286 PMCID: PMC6812822 DOI: 10.1371/journal.pone.0224121] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/06/2019] [Indexed: 01/23/2023] Open
Abstract
Purpose 4D and 2D phase-contrast MRI (2D Flow MRI, 4D Flow MRI, respectively) are increasingly being used to noninvasively assess pulmonary hypertension (PH). The goals of this study were i) to evaluate whether established quantitative parameters in 2D Flow MRI associated with pulmonary hypertension can be assessed using 4D Flow MRI; ii) to compare results from 4D Flow MRI on a digital broadband 3T MR system with data from clinically established MRI-techniques as well as conservation of mass analysis and phantom correction and iii) to elaborate on the added value of secondary flow patterns in detecting PH. Methods 11 patients with PH (4f, 63 ± 16y), 15 age-matched healthy volunteers (9f, 56 ± 11y), and 20 young healthy volunteers (13f, 23 ± 2y) were scanned on a 3T MR scanner (Philips Ingenia). Subjects were examined with a 4D Flow, a 2D Flow and a bSSFP sequence. For extrinsic comparison, quantitative parameters measured with 4D Flow MRI were compared to i) a static phantom, ii) 2D Flow acquisitions and iii) stroke volume derived from a bSSFP sequence. For intrinsic comparison conservation of mass-analysis was employed. Dedicated software was used to extract various flow, velocity, and anatomical parameters. Visualization of blood flow was performed to detect secondary flow patterns. Results Overall, there was good agreement between all techniques, 4D Flow results revealed a considerable spread. Data improved after phantom correction. Both 4D and 2D Flow MRI revealed concordant results to differentiate patients from healthy individuals, especially based on values derived from anatomical parameters. The visualization of a vortex, indicating the presence of PH was achieved in 9 /11 patients and 2/35 volunteers. Discussion This study confirms that quantitative parameters used for characterizing pulmonary hypertension can be gathered using 4D Flow MRI within clinically reasonable limits of agreement. Despite its unfavorable spatial and lesser temporal resolution and a non-neglible spread of results, the identification of diseased study participants was possible.
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Affiliation(s)
- Malte Maria Sieren
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
- * E-mail:
| | - Clara Berlin
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Thekla Helene Oechtering
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Peter Hunold
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Daniel Drömann
- Department of Pneumology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Jörg Barkhausen
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Alex Frydrychowicz
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany
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Viola F, Dyverfeldt P, Carlhäll CJ, Ebbers T. Data Quality and Optimal Background Correction Order of Respiratory-Gated k-Space Segmented Spoiled Gradient Echo (SGRE) and Echo Planar Imaging (EPI)-Based 4D Flow MRI. J Magn Reson Imaging 2019; 51:885-896. [PMID: 31332874 PMCID: PMC7027768 DOI: 10.1002/jmri.26879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 12/23/2022] Open
Abstract
Background A reduction in scan time of 4D Flow MRI would facilitate clinical application. A recent study indicates that echo‐planar imaging (EPI) 4D Flow MRI allows for a reduction in scan time and better data quality than the recommended k‐space segmented spoiled gradient echo (SGRE) sequence. It was argued that the poor data quality of SGRE was related to the nonrecommended absence of respiratory motion compensation. However, data quality can also be affected by the background offset compensation. Purpose To compare the data quality of respiratory motion‐compensated SGRE and EPI 4D Flow MRI and their dependence on background correction (BC) order. Study Type Retrospective. Subjects Eighteen healthy subjects (eight female, mean age 32 ± 5 years). Field Strength and Sequence 1.5 T. [Correction added on July 26, 2019, after first online publication: The preceding field strength was corrected.] SGRE and EPI‐based 4D Flow MRI. Assessment Data quality was investigated visually and by comparing flows through the cardiac valves and aorta. Measurements were obtained from transvalvular flow and pathline analysis. Statistical Tests Linear regression and Bland–Altman analysis were used. Wilcoxon test was used for comparison of visual scoring. Student's t‐test was used for comparison of flow volumes. Results No significant difference was found by visual inspection (P = 0.08). Left ventricular (LV) flows were strongly and very strongly associated with SGRE and EPI, respectively (R2 = 0.86–0.94 SGRE; 0.71–0.79 EPI, BC0–4). LV and right ventricular (RV) outflows and LV pathline flows were very strongly associated (R2 = 0.93–0.95 SGRE; 0.88–0.91 EPI, R2 = 0.91–0.95 SGRE; 0.91–0.93 EPI, BC1–4). EPI LV outflow was lower than the short‐axis‐based stroke volume. EPI RV outflow and proximal descending aortic flow were lower than SGREs. Data Conclusion Both sequences yielded good internal data consistency when an adequate background correction was applied. Second and first BC order were considered sufficient for transvalvular flow analysis in SGRE and EPI, respectively. Higher BC orders were preferred for particle tracing. Level of Evidence 4 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2020;51:885–896.
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Affiliation(s)
- Federica Viola
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, 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
| | - Carl-Johan Carlhäll
- 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, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - 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
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Automatic correction of background phase offset in 4D-flow of great vessels and of the heart in MRI using a third-order surface model. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 32:629-642. [DOI: 10.1007/s10334-019-00765-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 10/26/2022]
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Hofman MBM, Rodenburg MJA, Markenroth Bloch K, Werner B, Westenberg JJM, Valsangiacomo Buechel ER, Nijveldt R, Spruijt OA, Kilner PJ, van Rossum AC, Gatehouse PD. In-vivo validation of interpolation-based phase offset correction in cardiovascular magnetic resonance flow quantification: a multi-vendor, multi-center study. J Cardiovasc Magn Reson 2019; 21:30. [PMID: 31104632 PMCID: PMC6526620 DOI: 10.1186/s12968-019-0538-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 04/03/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A velocity offset error in phase contrast cardiovascular magnetic resonance (CMR) imaging is a known problem in clinical assessment of flow volumes in vessels around the heart. Earlier studies have shown that this offset error is clinically relevant over different systems, and cannot be removed by protocol optimization. Correction methods using phantom measurements are time consuming, and assume reproducibility of the offsets which is not the case for all systems. An alternative previously published solution is to correct the in-vivo data in post-processing, interpolating the velocity offset from stationary tissue within the field-of-view. This study aims to validate this interpolation-based offset correction in-vivo in a multi-vendor, multi-center setup. METHODS Data from six 1.5 T CMR systems were evaluated, with two systems from each of the three main vendors. At each system aortic and main pulmonary artery 2D flow studies were acquired during routine clinical or research examinations, with an additional phantom measurement using identical acquisition parameters. To verify the phantom acquisition, a region-of-interest (ROI) at stationary tissue in the thorax wall was placed and compared between in-vivo and phantom measurements. Interpolation-based offset correction was performed on the in-vivo data, after manually excluding regions of spatial wraparound. Correction performance of different spatial orders of interpolation planes was evaluated. RESULTS A total of 126 flow measurements in 82 subjects were included. At the thorax wall the agreement between in-vivo and phantom was - 0.2 ± 0.6 cm/s. Twenty-eight studies were excluded because of a difference at the thorax wall exceeding 0.6 cm/s from the phantom scan, leaving 98. Before correction, the offset at the vessel as assessed in the phantom was - 0.4 ± 1.5 cm/s, which resulted in a - 5 ± 16% error in cardiac output. The optimal order of the interpolation correction plane was 1st order, except for one system at which a 2nd order plane was required. Application of the interpolation-based correction revealed a remaining offset velocity of 0.1 ± 0.5 cm/s and 0 ± 5% error in cardiac output. CONCLUSIONS This study shows that interpolation-based offset correction reduces the offset with comparable efficacy as phantom measurement phase offset correction, without the time penalty imposed by phantom scans. TRIAL REGISTRATION The study was registered in The Netherlands National Trial Register (NTR) under TC 4865 . Registered 19 September 2014. Retrospectively registered.
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Affiliation(s)
- Mark B. M. Hofman
- Radiology and Nuclear Medicine, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Manouk J. A. Rodenburg
- Radiology and Nuclear Medicine, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Karin Markenroth Bloch
- Lund University Bioimaging Center, Lund University, SE-221 85 Lund, Sweden
- Philips Healthcare, SE-164 85 Stockholm, Sweden
| | - Beat Werner
- Department Diagnostic Imaging, University Children’s Hospital, Steinwiesstrasse 75, 8032 Zürich, Switzerland
| | - Jos J. M. Westenberg
- Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | | | - Robin Nijveldt
- Cardiology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Onno A. Spruijt
- Pulmonology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Philip J. Kilner
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
| | - Albert C. van Rossum
- Cardiology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Peter D. Gatehouse
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
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Loecher M, Magrath P, Aliotta E, Ennis DB. Time‐optimized 4D phase contrast MRI with real‐time convex optimization of gradient waveforms and fast excitation methods. Magn Reson Med 2019; 82:213-224. [DOI: 10.1002/mrm.27716] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 11/05/2022]
Affiliation(s)
- Michael Loecher
- Department of Radiological Sciences University of California Los Angeles California
| | - Patrick Magrath
- Department of Bioengineering University of California Los Angeles California
| | - Eric Aliotta
- Department of Biomedical Physics University of California Los Angeles California
| | - Daniel B. Ennis
- Department of Radiological Sciences University of California Los Angeles California
- Department of Bioengineering University of California Los Angeles California
- Department of Biomedical Physics University of California Los Angeles California
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29
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Cesarovic N, Busch J, Lipiski M, Fuetterer M, Fleischmann T, Born S, von Deuster C, Sauer M, Maisano F, Kozerke S, Stoeck CT. Left ventricular blood flow patterns at rest and under dobutamine stress in healthy pigs. NMR IN BIOMEDICINE 2019; 32:e4022. [PMID: 30403426 DOI: 10.1002/nbm.4022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/27/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Intracardiac blood flow patterns are affected by the morphology of cardiac structures and are set up to support the heart's pump function. Exercise affects contractility and chamber size as well as pre- and afterload. The aim of this study was to test the feasibility of four-dimensional phase contrast cardiovascular MRI under pharmacological stress and to study left ventricular blood flow under stress. 4D flow data were successfully acquired and analysed in 12 animals. During dobutamine infusion, heart rate and ejection fraction increased (82 ± 5 bpm versus 124 ± 3 bpm/46 ± 9% versus 65 ± 7%; both p < 0.05). A decrease in left ventricular end-diastolic volume (72 ± 14 mL versus 55 ± 8 mL; p < 0.05) and end-systolic volume (40 ± 15 mL versus 19 ± 6 mL; p < 0.05) but no change in stroke volume were observed. Trans-mitral diastolic inflow velocity increased under dobutamine and the trajectory of inflowing blood was directed towards the anterior septum with increased inflow angle (26 ± 5°) when compared with controls (15 ± 2°). In 5/6 animals undergoing stress diastolic vortices developed later, and in 3/6 animals vortices collapsed earlier with significantly smaller cross-sectional area during diastole. The vorticity index was not affected. Under the stress condition direct flow (% ejection within the next heart beat) increased from 43 ± 6% to 53 ± 8%. 4D MRI blood flow acquisition and analysis are feasible in pig hearts under dobutamine-induced stress. Flow patterns characterized by high blood velocity and antero-septally oriented diastolic inflow as well as decreased ventricular volumes are unfavourable conditions for diastolic vortex development under pharmacological stress, and cardiac output is increased by a rise in heart rate and directly ejected left ventricular blood volume.
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Affiliation(s)
- Nikola Cesarovic
- Division of Surgical Research, University Hospital Zurich, University of Zurich, Switzerland
| | - Julia Busch
- Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland
| | - Miriam Lipiski
- Division of Surgical Research, University Hospital Zurich, University of Zurich, Switzerland
| | - Maximilian Fuetterer
- Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland
| | - Thea Fleischmann
- Division of Surgical Research, University Hospital Zurich, University of Zurich, Switzerland
| | - Silvia Born
- Hybrid Laboratory for Cardiovascular Technologies, University of Zurich, Switzerland
| | | | - Mareike Sauer
- Division of Surgical Research, University Hospital Zurich, University of Zurich, Switzerland
| | - Francesco Maisano
- Clinic of Cardiovascular Surgery, University Hospital Zürich, University of Zürich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland
| | - Christian T Stoeck
- Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland
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30
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Pruitt AA, Jin N, Liu Y, Simonetti OP, Ahmad R. A method to correct background phase offset for phase-contrast MRI in the presence of steady flow and spatial wrap-around artifact. Magn Reson Med 2018; 81:2424-2438. [PMID: 30431176 DOI: 10.1002/mrm.27572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/13/2018] [Accepted: 09/27/2018] [Indexed: 11/11/2022]
Abstract
PURPOSE Background phase offsets in phase-contrast MRI are often corrected using polynomial regression; however, correction performance degrades when temporally invariant outliers such as steady flow or spatial wrap-around artifact are present. We describe and validate an iterative method called automatic rejection of temporally invariant outliers (ARTO), which excludes these outliers from the fitting process. METHODS The ARTO method iteratively removes pixels with large polynomial regression errors analyzed by a Gaussian mixture model fitting of the residual distribution. A total of 150 trials of a simulated phantom (75 with wrap-around artifact) and 125 phase-contrast MRI cines from 22 healthy subjects (48 with wrap-around artifact) were used for validation. Background phase offsets were corrected using second-order weighted regularized least squares (WRLS) with and without ARTO. Flow volumes after WRLS and WRLS+ARTO corrections were compared with the known truth (phantom) and stationary phantom reference (in vivo) using Bland-Altman analysis. The ratio between the pulmonary flow and the systemic flow was also computed in a subset of 6 subjects. RESULTS In the simulated phantom, compared with WRLS and no correction, correction with WRLS+ARTO produced superior agreement in volumetric flow quantification with the known truth. In vivo, WRLS+ARTO also produced superior agreement with stationary phantom-corrected volumetric flow compared with WRLS and no correction. In data sets with wrap-around artifact, WRLS produced significantly larger variance in the pulmonary flow and systemic flow ratio than stationary phantom correction (P = .0008). CONCLUSION The proposed method provides automatic exclusion of temporally invariant outliers and produces flow quantification results comparable to stationary phantom correction.
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Affiliation(s)
- Aaron A Pruitt
- Biomedical Engineering, Ohio State University, Columbus, Ohio
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Columbus, Ohio
| | - Yingmin Liu
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio
| | - Orlando P Simonetti
- Biomedical Engineering, Ohio State University, Columbus, Ohio.,Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio.,Internal Medicine, Ohio State University, Columbus, Ohio
| | - Rizwan Ahmad
- Biomedical Engineering, Ohio State University, Columbus, Ohio.,Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio.,Electrical and Computer Engineering, Ohio State University, Columbus, Ohio
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31
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Meuschke M, Gunther T, Berg P, Wickenhofer R, Preim B, Lawonn K. Visual Analysis of Aneurysm Data using Statistical Graphics. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2018; 25:997-1007. [PMID: 30130202 DOI: 10.1109/tvcg.2018.2864509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper presents a framework to explore multi-field data of aneurysms occurring at intracranial and cardiac arteries by using statistical graphics. The rupture of an aneurysm is often a fatal scenario, whereas during treatment serious complications for the patient can occur. Whether an aneurysm ruptures or whether a treatment is successful depends on the interaction of different morphological such as wall deformation and thickness, and hemodynamic attributes like wall shear stress and pressure. Therefore, medical researchers are very interested in better understanding these relationships. However, the required analysis is a time-consuming process, where suspicious wall regions are difficult to detect due to the time-dependent behavior of the data. Our proposed visualization framework enables medical researchers to efficiently assess aneurysm risk and treatment options. This comprises a powerful set of views including 2D and 3D depictions of the aneurysm morphology as well as statistical plots of different scalar fields. Brushing and linking aids the user to identify interesting wall regions and to understand the influence of different attributes on the aneurysm's state. Moreover, a visual comparison of pre- and post-treatment as well as different treatment options is provided. Our analysis techniques are designed in collaboration with domain experts, e.g., physicians, and we provide details about the evaluation.
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32
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Leijenaar JF, van Maurik IS, Kuijer JP, van der Flier WM, Scheltens P, Barkhof F, Prins ND. Lower cerebral blood flow in subjects with Alzheimer's dementia, mild cognitive impairment, and subjective cognitive decline using two-dimensional phase-contrast magnetic resonance imaging. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2017; 9:76-83. [PMID: 29234724 PMCID: PMC5717294 DOI: 10.1016/j.dadm.2017.10.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction In this cross-sectional study, we aimed to detect differences in cerebral blood flow (CBF) between subjects with Alzheimer's disease (AD), mild cognitive impairment (MCI), and subjective cognitive decline (SCD), using two-dimensional phase-contrast magnetic resonance imaging. Methods We included 74 AD patients (67 years, 51% female), 36 MCI patients (66 years, 33% female), and 62 patients with SCD (60 years, 32% female) from the Amsterdam Dementia Cohort. Patients with SCD are those who visited the memory clinic with subjective cognitive complaints without objective cognitive impairment. Whole-brain CBF (mL/100 g/min) was calculated using total volume flow measured with two-dimensional phase-contrast magnetic resonance imaging and normalized for brain volume. Results Mean CBF values (SD) were lower in AD compared to SCD (age and sex adjusted 70 ± 26 vs. 82 ± 24 mL/100 g/min, P < .05). Mean CBF values of MCI were comparable to AD. Across clinical groups, lower CBF was associated with lower scores on the Mini–Mental State Examination (age and sex adjusted stβ = 0.19 per mL/100 g/min; P = .02). Discussion Lower whole-brain CBF is seen in AD patients compared to SCD patients and is associated with worse cognitive function. The study consisted of a large sample of patients with AD, MCI, and controls. CBF measured with 2D PC MRI differed between AD patients and controls. Lower CBF was associated with worse cognitive function measured with MMSE. 2D PC MRI may be used as a marker for disease severity in a memory clinic.
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Affiliation(s)
- Jolien F. Leijenaar
- Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
- Corresponding author. Tel.: +31204440183; Fax: +31204448529.
| | - Ingrid S. van Maurik
- Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
- Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands
| | - Joost P.A. Kuijer
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Wiesje M. van der Flier
- Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
- Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands
| | - Philip Scheltens
- Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Frederik Barkhof
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
- Institutes of Neurology and Healthcare Engineering, UCL, London, United Kingdom
| | - Niels D. Prins
- Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
- Brain Research Center, Amsterdam, The Netherlands
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33
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Shen X, Schnell S, Barker AJ, Suwa K, Tashakkor L, Jarvis K, Carr JC, Collins JD, Prabhakaran S, Markl M. Voxel-by-voxel 4D flow MRI-based assessment of regional reverse flow in the aorta. J Magn Reson Imaging 2017; 47:1276-1286. [PMID: 28925047 DOI: 10.1002/jmri.25862] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/07/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Complex and reverse flow in the aorta has been implicated in aneurysm development and stroke via retrograde embolization. PURPOSE To evaluate global and regional differences between standard 2D plane-based and volumetric voxel-based quantification of regional forward/reverse flow, and reverse flow fraction (RFF) in the aorta. STUDY TYPE Retrospective. SUBJECTS In all, 35 subjects: 10 healthy controls (age: 57 ± 7 years, nine male), nine patients without aortic valve regurgitation (AR) (age: 63 ± 10 years, seven male), six patients with mild AR (age: 66 ± 6 years, five male), and 10 with moderate or severe AR (age: 60 ± 16 years, eight male). FIELD STRENGTH/SEQUENCE 4D flow MRI (3T and 1.5T) was employed to acquire 3D blood flow velocities with entire thoracic aorta in all subjects. ASSESSMENT Data analysis included standard 2D plane-based quantification of forward/reverse flow, and RFF-plane. In addition, a new semiautomatic workflow based on 3D segmentation and extraction of an aorta centerline was developed for voxel-by-voxel visualization (forward/reverse flow and RFF-voxel maps) and quantification of regional voxel-by-voxel forward/reverse flow in the entire thoracic aorta. STATISTICAL TESTS Kruskal-Wallis tests were performed to test for differences between groups. A two-sample t-test or Wilcoxon rank sum test was used to compare voxel-based and plane-based results. RESULTS Semiautomatic plane-based analysis showed excellent agreement with standard manual plane-based analysis for net flow and RFF-plane (RFF-plane: y = 0.99x-0.0, net flow: y = 1.00x-0.21, R > 0.99, P < 0.0001). Voxel-by-voxel maps demonstrated marked regional flow reversal in the ascending aorta in all patients and RFF-voxel was significantly increased (P < 0.001) compared to RFF-plane for all four groups, with the most pronounced differences for mild AR (18.0 ± 15.2% vs. 4.7 ± 5.4%). Voxel-based flow and RFF-voxel along the aorta showed areas with marked regional flow reversal (eg, vortex flow) compared to plane-based analysis. DATA CONCLUSION Voxel-based analysis demonstrated regional flow reversal that was not detected by plane-based analysis. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1276-1286.
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Affiliation(s)
- Xin Shen
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
| | - Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Alex J Barker
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Kenichiro Suwa
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Lingzi Tashakkor
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
| | - Kelly Jarvis
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
| | - James C Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Jeremy D Collins
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Shyam Prabhakaran
- Department of Neurology, Northwestern University, Chicago, Illinois, USA
| | - Michael Markl
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA.,Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Wu PH, Chung HW, Wu MT, Ko CW. Pixel-wise derivation of pulmonary regurgitation index could influence clinical decision: A phase-contrast MR imaging study on patients with repaired tetralogy of Fallot. Eur J Radiol 2017; 93:46-51. [PMID: 28668430 DOI: 10.1016/j.ejrad.2017.05.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/31/2017] [Accepted: 05/22/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE Regurgitant fraction (RF) measured from 2D phase-contrast MRI has been used as a standard to quantitate the degree of pulmonary regurgitation and serves as a determinant indicator of prognosis for tetralogy of Fallot after surgical repair. This study demonstrated the potential underestimate of RF using the conventional definition and its impact on clinical decision when backward flow occurred during systolic periods. METHODS Quantitative flow parameters, including forward flow volume (FFV), backward flow volume (BFV), and RF were estimated by two approaches: One derived from conventional ROI-averaged curve (bulk quantity) and the other in a pixel-wise manner to spatially reflect inhomogeneous flow profile (pixel-wise quantity). Eccentricity at systolic peak (Eccsys) was adopted as an index reflecting spatial flow inhomogeneity. RESULTS Flow parameters derived from ROI-averaged curves on main pulmonary artery were significantly smaller than that of pixel-wise measurement (P<0.001). Difference between RFbulk and RFpx for the group of Eccsys > 0.3 appears greater compared to the group with Eccsys < 0.3. Thirteen out of 68 RF values (19%) were underrated while using bulk analysis. CONCLUSIONS The spatial-related flow parameters showed more consistency with the qualitative flow profile pattern for pulmonary arteries, and could be a decisive complement for diagnostic classification.
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Affiliation(s)
- Pei-Hsin Wu
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA, 02115, USA.
| | - Hsiao-Wen Chung
- Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, No. 1, Sec.4, Roosevelt Rd., Taipei, 10617, Taiwan.
| | - Ming-Ting Wu
- Department of Radiology, Kaohsiung Veterans General Hospital, No.386, Dazhong 1 st Rd. Kaohsiung, Kaohsiung, 81362, Taiwan; Faculty of Medicine, School of Medicine, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei, 11221, Taiwan.
| | - Cheng-Wen Ko
- Department of Computer Science and Engineering, National Sun Yat-sen University, No.70, Lien-Hai Rd., Kaohsiung, 80424, Taiwan.
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Busch J, Giese D, Kozerke S. Image-based background phase error correction in 4D flow MRI revisited. J Magn Reson Imaging 2017; 46:1516-1525. [PMID: 28225577 DOI: 10.1002/jmri.25668] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 01/26/2017] [Indexed: 11/07/2022] Open
Affiliation(s)
- Julia Busch
- Institute for Biomedical Engineering; University of Zurich and ETH Zurich; Zurich Switzerland
| | - Daniel Giese
- Department of Radiology; University Hospital Cologne; Cologne Germany
| | - Sebastian Kozerke
- Institute for Biomedical Engineering; University of Zurich and ETH Zurich; Zurich Switzerland
- Division of Imaging Science and Biomedical Engineering; King's College London; London UK
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36
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Lin Y, Jiang K, Chung YC. Comparison of Two Methods for Correcting Baseline Offset Error in Phase-Contrast MR Imaging. J Cardiovasc Magn Reson 2016. [PMCID: PMC5032732 DOI: 10.1186/1532-429x-18-s1-p334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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Bollache E, van Ooij P, Powell A, Carr J, Markl M, Barker AJ. Comparison of 4D flow and 2D velocity-encoded phase contrast MRI sequences for the evaluation of aortic hemodynamics. Int J Cardiovasc Imaging 2016; 32:1529-41. [PMID: 27435230 DOI: 10.1007/s10554-016-0938-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 07/09/2016] [Indexed: 01/08/2023]
Abstract
The purpose of this study was to compare aortic flow and velocity quantification using 4D flow MRI and 2D CINE phase-contrast (PC)-MRI with either one-directional (2D-1dir) or three-directional (2D-3dir) velocity encoding. 15 healthy volunteers (51 ± 19 years) underwent MRI including (1) breath-holding 2D-1dir and (2) free breathing 2D-3dir PC-MRI in planes orthogonal to the ascending (AA) and descending (DA) aorta, as well as (3) free breathing 4D flow MRI with full thoracic aorta coverage. Flow quantification included the co-registration of the 2D PC acquisition planes with 4D flow MRI data, AA and DA segmentation, and calculation of AA and DA peak systolic velocity, peak flow and net flow volume for all sequences. Additionally, the 2D-3dir velocity taking into account the through-plane component only was used to obtain results analogous to a free breathing 2D-1dir acquisition. Good agreement was found between 4D flow and 2D-3dir peak velocity (differences = -3 to 6 %), peak flow (-7 %) and net volume (-14 to -9 %). In contrast, breath-holding 2D-1dir measurements exhibited indices significantly lower than free breathing 2D-3dir and 2D-1dir (differences = -35 to -7 %, p < 0.05). Finally, high correlations (r ≥ 0.97) were obtained for indices estimated with or without eddy current correction, with the lowest correlation observed for net volume. 4D flow and 2D-3dir aortic hemodynamic indices were in concordance. However, differences between respiration state and 2D-1dir and 2D-3dir measurements indicate that reference values should be established according to the PC-MRI sequence, especially for the widely used net flow (e.g. stroke volume in the AA).
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Affiliation(s)
- Emilie Bollache
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA.
| | - Pim van Ooij
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA
| | - Alex Powell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA
| | - James Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA.,Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA
| | - Alex J Barker
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan ave-Suite 1600, Chicago, IL, 60611, USA
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Abstract
Pulmonary hypertension (PH) is a life-threatening, multifactorial pathophysiological haemodynamic condition, diagnosed when the mean pulmonary arterial pressure equals or exceeds 25 mmHg at rest during right heart catheterization. Cardiac MRI, in general, and MR phase-contrast (PC) imaging, in particular, have emerged as potential techniques for the standardized assessment of cardiovascular function, morphology and haemodynamics in PH. Allowing the quantification and characterization of macroscopic cardiovascular blood flow, MR PC imaging offers non-invasive evaluation of haemodynamic alterations associated with PH. Techniques used to study the PH include both the routine two-dimensional (2D) approach measuring predominant velocities through an acquisition plane and the rapidly evolving four-dimensional (4D) PC imaging, which enables the assessment of the complete time-resolved, three-directional blood-flow velocity field in a volume. Numerous parameters such as pulmonary arterial mean velocity, vessel distensibility, flow acceleration time and volume and tricuspid regurgitation peak velocity, as well as the duration and onset of vortical blood flow in the main pulmonary artery, have been explored to either diagnose PH or find non-invasive correlates to right heart catheter parameters. Furthermore, PC imaging-based analysis of pulmonary arterial pulse-wave velocities, wall shear stress and kinetic energy losses grants novel insights into cardiopulmonary remodelling in PH. This review aimed to outline the current applications of 2D and 4D PC imaging in PH and show why this technique has the potential to contribute significantly to early diagnosis and characterization of PH.
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Affiliation(s)
- Ursula Reiter
- 1 Division of General Radiology, Department of Radiology, Medical University of Graz, Austria
| | - Gert Reiter
- 2 Research and Development, Siemens Healthcare, Graz, Austria
| | - Michael Fuchsjäger
- 1 Division of General Radiology, Department of Radiology, Medical University of Graz, Austria
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Phase Error Correction in Time-Averaged 3D Phase Contrast Magnetic Resonance Imaging of the Cerebral Vasculature. PLoS One 2016; 11:e0149930. [PMID: 26910600 PMCID: PMC4765993 DOI: 10.1371/journal.pone.0149930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022] Open
Abstract
Purpose Volume flow rate (VFR) measurements based on phase contrast (PC)-magnetic resonance (MR) imaging datasets have spatially varying bias due to eddy current induced phase errors. The purpose of this study was to assess the impact of phase errors in time averaged PC-MR imaging of the cerebral vasculature and explore the effects of three common correction schemes (local bias correction (LBC), local polynomial correction (LPC), and whole brain polynomial correction (WBPC)). Methods Measurements of the eddy current induced phase error from a static phantom were first obtained. In thirty healthy human subjects, the methods were then assessed in background tissue to determine if local phase offsets could be removed. Finally, the techniques were used to correct VFR measurements in cerebral vessels and compared statistically. Results In the phantom, phase error was measured to be <2.1 ml/s per pixel and the bias was reduced with the correction schemes. In background tissue, the bias was significantly reduced, by 65.6% (LBC), 58.4% (LPC) and 47.7% (WBPC) (p < 0.001 across all schemes). Correction did not lead to significantly different VFR measurements in the vessels (p = 0.997). In the vessel measurements, the three correction schemes led to flow measurement differences of -0.04 ± 0.05 ml/s, 0.09 ± 0.16 ml/s, and -0.02 ± 0.06 ml/s. Although there was an improvement in background measurements with correction, there was no statistical difference between the three correction schemes (p = 0.242 in background and p = 0.738 in vessels). Conclusions While eddy current induced phase errors can vary between hardware and sequence configurations, our results showed that the impact is small in a typical brain PC-MR protocol and does not have a significant effect on VFR measurements in cerebral vessels.
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Boye D, Springer O, Wassmer F, Scheidegger S, Remonda L, Berberat J. Effects of contour propagation and background corrections in different MRI flow software packages. Acta Radiol Open 2015; 4:2058460115589124. [PMID: 26346318 PMCID: PMC4548733 DOI: 10.1177/2058460115589124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/07/2015] [Indexed: 11/23/2022] Open
Abstract
Background Velocity-encoded magnetic resonance imaging (VENC-MRI) is a commonly used technique in cardiac examinations. This technique utilizes the phase shift properties of protons moving along a magnetic field gradient. VENC-MRI offers a unique way of measuring the severity of valve regurgitation by directly quantifying the regurgitation flow volume. Purpose To compare flow analysis results of different software programs and to assess the effect of background correction in sample patient cases. Material and Methods A phantom was built out of Polymethyl methacrylate (PMMA) which provides tubes of different diameters. These tubes can be connected to an external water circuit to generate a water flow inside the tubes. Expected absolute flow quantities inside the tubes were determined from preset tube- and flow-parameters. Different flow conditions were measured with a VENC-MRI sequence and the images evaluated using different software packages. In a second step six randomly selected patients showing different degrees of aortic insufficiency were evaluated in clinical terms. Results The contour propagation algorithms used in the software packages performed differently even on static phantom geometry. In terms of clinical evaluation the software packages performed similarly. Enabling background correction or leaving out manual correction of propagated contours changed results for severity of aortic insufficiency. Conclusion Turning on background correction and manual correction of propagated contours in MRI flow volume measurements is strongly recommended.
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Affiliation(s)
- D Boye
- Cantonal Hospital Aarau, Department of Neuroradiology, Aarau, Switzerland
| | - O Springer
- Cantonal Hospital Aarau, Department of Radiology, Aarau, Switzerland
| | - F Wassmer
- Zurich University of Applied Sciences, Institute of Applied Mathematics and Physics, Winterthur, Switzerland
| | - S Scheidegger
- Zurich University of Applied Sciences, Institute of Applied Mathematics and Physics, Winterthur, Switzerland
| | - L Remonda
- Cantonal Hospital Aarau, Department of Neuroradiology, Aarau, Switzerland
| | - J Berberat
- Cantonal Hospital Aarau, Department of Neuroradiology, Aarau, Switzerland
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Nayak KS, Nielsen JF, Bernstein MA, Markl M, D Gatehouse P, M Botnar R, Saloner D, Lorenz C, Wen H, S Hu B, Epstein FH, N Oshinski J, Raman SV. Cardiovascular magnetic resonance phase contrast imaging. J Cardiovasc Magn Reson 2015; 17:71. [PMID: 26254979 PMCID: PMC4529988 DOI: 10.1186/s12968-015-0172-7] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/16/2015] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today's latest technology.
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Affiliation(s)
- Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, California, 90089-2564, USA.
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | | | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, IL, USA.
| | - Peter D Gatehouse
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK.
| | - Rene M Botnar
- Cardiovascular Imaging, Imaging Sciences Division, Kings's College London, London, UK.
| | - David Saloner
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Christine Lorenz
- Center for Applied Medical Imaging, Siemens Corporation, Baltimore, MD, USA.
| | - Han Wen
- Imaging Physics Laboratory, National Heart Lung and Blood Institute, Bethesda, MD, USA.
| | - Bob S Hu
- Palo Alto Medical Foundation, Palo Alto, CA, USA.
| | - Frederick H Epstein
- Departments of Radiology and Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
| | - John N Oshinski
- Departments of Radiology and Biomedical Engineering, Emory University School of Medicine, Atlanta, GA, USA.
| | - Subha V Raman
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA.
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Pulmonary regurgitant volume is superior to fraction using background-corrected phase contrast MRI in determining the severity of regurgitation in repaired tetralogy of Fallot. Int J Cardiovasc Imaging 2015; 31:1169-77. [PMID: 25944487 PMCID: PMC4486784 DOI: 10.1007/s10554-015-0670-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/27/2015] [Indexed: 11/15/2022]
Abstract
In the assessment of pulmonary regurgitation (PR) using phase contrast MRI, phase offset errors affect the accuracy of flow. This study evaluated the use of automated background correction for phase offset in the quantification of PR fraction and volume in patients with repaired tetralogy of Fallot (TOF), and to assess its clinical impact. We retrospectively analyzed 203 cardiac MRI studies, performed on 1.5-T scanner. Pulmonary flow (QP) and systemic flow (QS) was assessed both with and without background correction. Non-corrected and corrected QP was correlated with QS. PR was correlated with (1) indexed right ventricular end-diastolic volume (RVEDVi) and (2) with differential right and left ventricular stroke volumes (PRSV). Both PR fraction and volume showed major change after correction (−43 to +36 % and −13 to +13 ml/m2). Corrected QP and QS were stronger correlated with each other than non-corrected QP and QS [r = 0.78 vs. 0.73 (p < 0.001)]. Both PR fraction and volume were stronger correlated with RVEDVi, compared to their non-corrected counterparts (p < 0.001). PR volume was stronger correlated with RVEDVi, compared to PR fraction [r = 0.74 vs. 0.69 (p < 0.001)]. When patients were divided according to PR severity, 12 % of patients reclassified after correction. Background correction for phase offset significantly changed the quantification of PR. Non-corrected assessment of PR may result in the misclassification of patients. Our data suggest that the use of PR volume is favourable in the follow-up of patients with repaired TOF.
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In vivo analysis of physiological 3D blood flow of cerebral veins. Eur Radiol 2015; 25:2371-80. [PMID: 25638218 DOI: 10.1007/s00330-014-3587-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 12/16/2014] [Accepted: 12/24/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To visualize and quantify physiological blood flow of intracranial veins in vivo using time-resolved, 3D phase-contrast MRI (4D flow MRI), and to test measurement accuracy. METHODS Fifteen healthy volunteers underwent repeated ECG-triggered 4D flow MRI (3 Tesla, 32-channel head coil). Intracranial venous blood flow was analysed using dedicated software allowing for blood flow visualization and quantification in analysis planes at the superior sagittal, straight, and transverse sinuses. MRI was evaluated for intra- and inter-observer agreement and scan-rescan reproducibility. Measurements of the transverse sinuses were compared with transcranial two-dimensional duplex ultrasound. RESULTS Visualization of 3D blood flow within cerebral sinuses was feasible in 100 % and within at least one deep cerebral vein in 87 % of the volunteers. Blood flow velocity/volume increased along the superior sagittal sinus and was lower in the left compared to the right transverse sinus. Intra- and inter-observer reliability and reproducibility of blood flow velocity (mean difference 0.01/0.02/0.02 m/s) and volume (mean difference 0.0002/-0.0003/0.00003 l/s) were good to excellent. High/low velocities were more pronounced (8 % overestimation/9 % underestimation) in MRI compared to ultrasound. CONCLUSIONS Four-dimensional flow MRI reliably visualizes and quantifies three-dimensional cerebral venous blood flow in vivo and is promising for studies in patients with sinus thrombosis and related diseases. KEY POINTS • 4D flow MRI can be used to visualize and quantify physiological cerebral venous haemodynamics • Flow quantification within cerebral sinuses reveals high reliability and accuracy of 4D flow MRI • Blood flow volume and velocity increase along the superior sagittal sinus • Limited spatial resolution currently precludes flow quantification in small cerebral veins.
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Meierhofer C, Lyko C, Schneider EP, Stern H, Martinoff S, Hess J, Fratz S. Baseline correction does not improve flow quantification in phase-contrast velocity measurement for routine clinical practice. Clin Imaging 2014; 39:427-31. [PMID: 25661574 DOI: 10.1016/j.clinimag.2014.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 12/14/2014] [Accepted: 12/16/2014] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Velocity offset errors may influence flow measurement in phase-contrast cardiovascular magnetic resonance (CMR). By using a stationary gel phantom, offset errors probably may be corrected. We tested its impact on flow measurement and, in particular, on shunt calculation in patients proven not to have any shunt. METHODS Flow measurements were carried out in 24 patients with congenital heart disease. Baseline correction was performed by using a stationary gel phantom. RESULTS Significantly more patients without shunts incorrectly showed a calculated shunt after baseline correction. CONCLUSIONS Baseline correction did not improve flow measurement and was clinically not relevant for routine CMR.
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Affiliation(s)
- Christian Meierhofer
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany.
| | - Christine Lyko
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
| | - Eike Philipp Schneider
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
| | - Heiko Stern
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
| | - Stefan Martinoff
- Division of Radiology, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
| | - John Hess
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
| | - Sohrab Fratz
- Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich, Germany
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Busch J, Vannesjo SJ, Barmet C, Pruessmann KP, Kozerke S. Analysis of temperature dependence of background phase errors in phase-contrast cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2014; 16:97. [PMID: 25497004 PMCID: PMC4263200 DOI: 10.1186/s12968-014-0097-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/14/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The accuracy of phase-contrast cardiovascular magnetic resonance (PC-CMR) can be compromised by background phase errors. It is the objective of the present work to provide an analysis of the temperature dependence of background phase errors in PC-CMR by means of gradient mount temperature sensing and magnetic field monitoring. METHODS Background phase errors were measured for various temperatures of the gradient mount using magnetic field monitoring and validated in a static phantom. The effect of thermal changes during k-space acquisition was simulated and confirmed with measurements in a stationary phantom. RESULTS The temperature of the gradient mount was found to increase by 20-30 K during PC-CMR measurements of 6-12 min duration. Associated changes in background phase errors of up to 11% or 0.35 radian were measured at 10 cm from the magnet's iso-center as a result of first order offsets. Zeroth order phase errors exhibited little thermal dependence. CONCLUSIONS It is concluded that changes in gradient mount temperature significantly modify background phase errors during PC-CMR with high gradient duty cycle. Since temperature increases significantly during the first minutes of scanning the results presented are also of relevance for single-slice or multi-slice PC-CMR scans. The findings prompt for further studies to investigate advanced correction methods taking into account gradient temperature and/or the use of concurrent field-monitoring to map gradient-induced fields throughout the scan.
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Affiliation(s)
- Julia Busch
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - S Johanna Vannesjo
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Christoph Barmet
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Skope Magnetic Resonance Technologies, Zurich, Switzerland
| | - Klaas P Pruessmann
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Division of Imaging Science and Biomedical Engineering, King’s College London, London, UK
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Jiang J, Kokeny P, Ying W, Magnano C, Zivadinov R, Mark Haacke E. Quantifying errors in flow measurement using phase contrast magnetic resonance imaging: comparison of several boundary detection methods. Magn Reson Imaging 2014; 33:185-93. [PMID: 25460329 DOI: 10.1016/j.mri.2014.10.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 10/12/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
Abstract
Quantifying flow from phase-contrast MRI (PC-MRI) data requires that the vessels of interest be segmented. The estimate of the vessel area will dictate the type and magnitude of the error sources that affect the flow measurement. These sources of errors are well understood, and mathematical expressions have been derived for them in previous work. However, these expressions contain many parameters that render them difficult to use for making practical error estimates. In this work, some realistic assumptions were made that allow for the simplification of such expressions in order to make them more useful. These simplified expressions were then used to numerically simulate the effect of segmentation accuracy and provide some criteria that if met, would keep errors in flow quantification below 10% or 5%. Four different segmentation methods were used on simulated and phantom MRA data to verify the theoretical results. Numerical simulations showed that including partial volumed edge pixels in vessel segmentation provides less error than missing them. This was verified with MRA simulations, as the best performing segmentation method generally included such pixels. Further, it was found that to obtain a flow error of less than 10% (5%), the vessel should be at least 4 (5) pixels in diameter, have an SNR of at least 10:1 and have a peak velocity to saturation cut-off velocity ratio of at least 5:3.
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Affiliation(s)
- Jing Jiang
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Department of Radiology, Wayne State University, Detroit, MI, USA
| | - Paul Kokeny
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Magnetic Resonance Innovations, Inc., Detroit, MI, USA
| | - Wang Ying
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; College of Information Science and Engineering, Northeastern University, Shenyang, Liaoning province, China
| | - Chris Magnano
- Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA
| | - E Mark Haacke
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Department of Radiology, Wayne State University, Detroit, MI, USA; Magnetic Resonance Innovations, Inc., Detroit, MI, USA; Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada.
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Hansen MS, Olivieri LJ, O’Brien K, Cross RR, Inati SJ, Kellman P. Method for calculating confidence intervals for phase contrast flow measurements. J Cardiovasc Magn Reson 2014; 16:46. [PMID: 24962371 PMCID: PMC4079643 DOI: 10.1186/1532-429x-16-46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/13/2014] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Phase contrast (PC) measurements play an important role in several cardiovascular magnetic resonance (CMR) protocols but considerable variation is observed in such measurements. Part of this variation stems from the propagation of thermal noise from the measurement data through the image reconstruction to the region of interest analysis used in flow measurement, which limits the precision. The purpose of this study was to develop a method for direct estimation of the variation caused by thermal noise and to validate this method in phantom and in vivo data. METHODS The estimation of confidence intervals in flow measurements is complicated by noise correlation among the image pixels and cardiac phases. This correlation is caused by sequence and reconstruction parameters. A method for the calculation of the standard deviation of region of interest measurements was adapted and expanded to accommodate typical clinical PC measurements and the region-of-interest analysis used for such measurements. This included the dependency between cardiac phases that arises due to retrospective cardiac gating used in such studies. The proposed method enables calculation of standard deviations of flow measurements without the need for repeated experiments or repeated reconstructions. The method was compared to repeated trials in phantom measurements and pseudo replica reconstructions of in vivo data. Three different flow protocols (free breathing and breath hold with various accelerations) were compared in terms of the confidence interval ranges caused by thermal noise in the measurement data. RESULTS Using the proposed method it was possible to accurately predict confidence intervals for flow measurements. The method was in good agreement with repeated measurements in phantom experiments and there was also good agreement with confidence intervals predicted by pseudo replica reconstructions in both phantom and in vivo data. The proposed method was used to demonstrate that the variation in cardiac output caused by thermal noise is on the order of 1% in clinically used free breathing protocols, and on the order of 3-5% in breath-hold protocols with higher parallel imaging factors. CONCLUSIONS It is possible to calculate confidence intervals for Cartesian PC contrast flow measurements directly without the need for time-consuming pseudo replica reconstructions.
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Affiliation(s)
- Michael S Hansen
- National Heart, Lung, and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
| | - Laura J Olivieri
- National Heart, Lung, and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
- Division of Cardiology, Children’s National Medical Center, 111 Michigan Ave., N.W, Washington, DC 20010, USA
| | - Kendall O’Brien
- National Heart, Lung, and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
- Division of Cardiology, Children’s National Medical Center, 111 Michigan Ave., N.W, Washington, DC 20010, USA
| | - Russell R Cross
- National Heart, Lung, and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
- Division of Cardiology, Children’s National Medical Center, 111 Michigan Ave., N.W, Washington, DC 20010, USA
| | - Souheil J Inati
- National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
| | - Peter Kellman
- National Heart, Lung, and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20814, USA
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Giese D, Wong J, Greil GF, Buehrer M, Schaeffter T, Kozerke S. Towards highly accelerated Cartesian time-resolved 3D flow cardiovascular magnetic resonance in the clinical setting. J Cardiovasc Magn Reson 2014; 16:42. [PMID: 24942253 PMCID: PMC4230248 DOI: 10.1186/1532-429x-16-42] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The clinical applicability of time-resolved 3D flow cardiovascular magnetic resonance (CMR) remains compromised by the long scan times associated with phase-contrast imaging. The present work demonstrates the applicability of 8-fold acceleration of Cartesian time-resolved 3D flow CMR in 10 volunteers and in 9 patients with different congenital heart diseases (CHD). It is demonstrated that accelerated 3D flow CMR data acquisition and image reconstruction using k-t PCA (principal component analysis) can be implemented into clinical workflow and results are sufficiently accurate relative to conventional 2D flow CMR to permit for comprehensive flow quantification in CHD patients. METHODS The fidelity of k-t PCA was first investigated on retrospectively undersampled data for different acceleration factors and compared to k-t SENSE and fully sampled reference data. Subsequently, k-t PCA with 8-fold nominal undersampling was applied on 10 healthy volunteers and 9 CHD patients on a clinical 1.5 T MR scanner. Quantitative flow validation was performed in vessels of interest on the 3D flow datasets and compared to 2D through-plane flow acquisitions. Particle trace analysis was used to qualitatively visualise flow patterns in patients. RESULTS Accelerated time-resolved 3D flow data were successfully acquired in all subjects with 8-fold nominal scan acceleration. Nominal scan times excluding navigator efficiency were on the order of 6 min and 7 min in patients and volunteers. Mean differences in stroke volume in selected vessels of interest were 2.5 ± 8.4 ml and 1.63 ± 4.8 ml in volunteers and patients, respectively. Qualitative flow pattern analysis in the time-resolved 3D dataset revealed valuable insights into hemodynamics including circular and helical patterns as well as flow distributions and origin in the Fontan circulation. CONCLUSION Highly accelerated time-resolved 3D flow using k-t PCA is readily applicable in clinical routine protocols of CHD patients. Nominal scan times of 6 min are well tolerated and allow for quantitative and qualitative flow assessment in all great vessels.
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Affiliation(s)
- Daniel Giese
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
- Department of Radiology, University of Cologne, Cologne, Germany
| | - James Wong
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Gerald F Greil
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Martin Buehrer
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Tobias Schaeffter
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Sebastian Kozerke
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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Nilsson A, Revstedt J, Heiberg E, Ståhlberg F, Bloch KM. Volumetric velocity measurements in restricted geometries using spiral sampling: a phantom study. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2014; 28:103-18. [PMID: 24838252 DOI: 10.1007/s10334-014-0449-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/28/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
Abstract
OBJECT The aim of this study was to evaluate the accuracy of maximum velocity measurements using volumetric phase-contrast imaging with spiral readouts in a stenotic flow phantom. MATERIALS AND METHODS In a phantom model, maximum velocity, flow, pressure gradient, and streamline visualizations were evaluated using volumetric phase-contrast magnetic resonance imaging (MRI) with velocity encoding in one (extending on current clinical practice) and three directions (for characterization of the flow field) using spiral readouts. Results of maximum velocity and pressure drop were compared to computational fluid dynamics (CFD) simulations, as well as corresponding low-echo-time (TE) Cartesian data. Flow was compared to 2D through-plane phase contrast (PC) upstream from the restriction. RESULTS Results obtained with 3D through-plane PC as well as 4D PC at shortest TE using a spiral readout showed excellent agreements with the maximum velocity values obtained with CFD (<1 % for both methods), while larger deviations were seen using Cartesian readouts (-2.3 and 13 %, respectively). Peak pressure drop calculations from 3D through-plane PC and 4D PC spiral sequences were respectively 14 and 13 % overestimated compared to CFD. CONCLUSION Identification of the maximum velocity location, as well as the accurate velocity quantification can be obtained in stenotic regions using short-TE spiral volumetric PC imaging.
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Affiliation(s)
- Anders Nilsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden,
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50
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Rigsby CK, Hilpipre N, McNeal GR, Zhang G, Boylan EE, Popescu AR, Choi G, Greiser A, Deng J. Analysis of an automated background correction method for cardiovascular MR phase contrast imaging in children and young adults. Pediatr Radiol 2014; 44:265-73. [PMID: 24306733 DOI: 10.1007/s00247-013-2830-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/16/2013] [Accepted: 10/21/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Phase contrast magnetic resonance imaging (MRI) is a powerful tool for evaluating vessel blood flow. Inherent errors in acquisition, such as phase offset, eddy currents and gradient field effects, can cause significant inaccuracies in flow parameters. These errors can be rectified with the use of background correction software. OBJECTIVE To evaluate the performance of an automated phase contrast MRI background phase correction method in children and young adults undergoing cardiac MR imaging. MATERIALS AND METHODS We conducted a retrospective review of patients undergoing routine clinical cardiac MRI including phase contrast MRI for flow quantification in the aorta (Ao) and main pulmonary artery (MPA). When phase contrast MRI of the right and left pulmonary arteries was also performed, these data were included. We excluded patients with known shunts and metallic implants causing visible MRI artifact and those with more than mild to moderate aortic or pulmonary stenosis. Phase contrast MRI of the Ao, mid MPA, proximal right pulmonary artery (RPA) and left pulmonary artery (LPA) using 2-D gradient echo Fast Low Angle SHot (FLASH) imaging was acquired during normal respiration with retrospective cardiac gating. Standard phase image reconstruction and the automatic spatially dependent background-phase-corrected reconstruction were performed on each phase contrast MRI dataset. Non-background-corrected and background-phase-corrected net flow, forward flow, regurgitant volume, regurgitant fraction, and vessel cardiac output were recorded for each vessel. We compared standard non-background-corrected and background-phase-corrected mean flow values for the Ao and MPA. The ratio of pulmonary to systemic blood flow (Qp:Qs) was calculated for the standard non-background and background-phase-corrected data and these values were compared to each other and for proximity to 1. In a subset of patients who also underwent phase contrast MRI of the MPA, RPA, and LPA a comparison was made between standard non-background-corrected and background-phase-corrected mean combined flow in the branch pulmonary arteries and MPA flow. All comparisons were performed using the Wilcoxon sign rank test (α = 0.05). RESULTS Eighty-five children and young adults (mean age 14 years; range 10 days to 32 years) met the criteria for inclusion. Background-phase-corrected mean flow values for the Ao and MPA were significantly lower than those for non-background-corrected standard Ao (P = 0.0004) and MPA flow values (P < 0.0001), respectively. However, no significant difference was seen between the standard non-background (P = 0.295) or background-phase-corrected (P = 0.0653) mean Ao and MPA flow values. Neither the mean standard non-background-corrected (P = 0.408) nor the background-phase-corrected (P = 0.0684) Qp:Qs was significantly different from 1. However in the 27 patients with standard non-background-corrected data, the difference between the Ao and MPA flow values was greater than 10%. There were 19 patients with background-phase-corrected data in which the difference between the Ao and MPA flow values was greater than 10%. In the subset of 43 patients who underwent MPA and branch pulmonary artery phase contrast MRI, the sum of the standard non-background-corrected mean RPA and LPA flow values was significantly different from the standard non-background-corrected mean MPA flow (P = 0.0337). The sum of the background-phase-corrected mean RPA and LPA flow values was not significantly different from the background-phase-corrected mean MPA flow value (P = 0.1328), suggesting improvement in pulmonary artery flow calculations using background-phase-correction. CONCLUSION Our data suggest that background phase correction of phase contrast MRI data does not significantly change Qp:Qs quantification, and there are residual errors in expected Qp:Qs quantification despite background phase correction. However the use of background phase correction does improve quantification of MPA flow relative to combined RPA and LPA flow. Further work is needed to validate these findings in other patient populations, using other MRI units, and across vendors.
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Affiliation(s)
- Cynthia K Rigsby
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave, Box 9, Chicago, IL, 60611, USA,
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