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Yang H, Hong K, Baraboo JJ, Fan L, Larsen A, Markl M, Robinson JD, Rigsby CK, Kim D. GRASP reconstruction amplified with view-sharing and KWIC filtering reduces underestimation of peak velocity in highly-accelerated real-time phase-contrast MRI: A preliminary evaluation in pediatric patients with congenital heart disease. Magn Reson Med 2024; 91:1965-1977. [PMID: 38084397 PMCID: PMC10950531 DOI: 10.1002/mrm.29974] [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: 08/10/2023] [Revised: 10/27/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
PURPOSE To develop a highly-accelerated, real-time phase contrast (rtPC) MRI pulse sequence with 40 fps frame rate (25 ms effective temporal resolution). METHODS Highly-accelerated golden-angle radial sparse parallel (GRASP) with over regularization may result in temporal blurring, which in turn causes underestimation of peak velocity. Thus, we amplified GRASP performance by synergistically combining view-sharing (VS) and k-space weighted image contrast (KWIC) filtering. In 17 pediatric patients with congenital heart disease (CHD), the conventional GRASP and the proposed GRASP amplified by VS and KWIC (or GRASP + VS + KWIC) reconstruction for rtPC MRI were compared with respect to clinical standard PC MRI in measuring hemodynamic parameters (peak velocity, forward volume, backward volume, regurgitant fraction) at four locations (aortic valve, pulmonary valve, left and right pulmonary arteries). RESULTS The proposed reconstruction method (GRASP + VS + KWIC) achieved better effective spatial resolution (i.e., image sharpness) compared with conventional GRASP, ultimately reducing the underestimation of peak velocity from 17.4% to 6.4%. The hemodynamic metrics (peak velocity, volumes) were not significantly (p > 0.99) different between GRASP + VS + KWIC and clinical PC, whereas peak velocity was significantly (p < 0.007) lower for conventional GRASP. RtPC with GRASP + VS + KWIC also showed the ability to assess beat-to-beat variation and detect the highest peak among peaks. CONCLUSION The synergistic combination of GRASP, VS, and KWIC achieves 25 ms effective temporal resolution (40 fps frame rate), while minimizing the underestimation of peak velocity compared with conventional GRASP.
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Affiliation(s)
- Huili Yang
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
| | - KyungPyo Hong
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Justin J Baraboo
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
| | - Lexiaozi Fan
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
| | - Andrine Larsen
- Department of Biomedical Engineering, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Michael Markl
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
| | - Joshua D Robinson
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Division of Cardiology, Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois, USA
| | - Cynthia K Rigsby
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois, USA
| | - Daniel Kim
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
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Müller N, Härtel JA, Schmitz J, Baur U, von der Wiesche M, Rieger I, Gerlach D, von Stritzky J, Bach A, Hart C, Bros J, Seeger B, Zollmann E, Grau M, Dragutinovic B, de Boni LM, Hönemann JN, Bloch W, Aeschbach D, Elmenhorst EM, Herberg U, Hess A, Schumann M, Kratz T, Jordan J, Breuer J, Tank J. Peripheral Oxygenation and Pulmonary Hemodynamics in Individuals With Fontan Circulation During 24-Hour High-Altitude Exposure Simulation. Circulation 2024; 149:1466-1468. [PMID: 38683898 DOI: 10.1161/circulationaha.123.067601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Affiliation(s)
- Nicole Müller
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Julian Alexander Härtel
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Jan Schmitz
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Cologne, Germany (J.S.)
| | - Ute Baur
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Melanie von der Wiesche
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Iris Rieger
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Darius Gerlach
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Jon von Stritzky
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Anja Bach
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Christopher Hart
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Janina Bros
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Benedikt Seeger
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Emily Zollmann
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Marijke Grau
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Boris Dragutinovic
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Laura-Maria de Boni
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Jan-Niklas Hönemann
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Clinic III for Internal Medicine, Cologne, Germany (J.-N.H.)
- Department of Internal Medicine III, Division of Cardiology, Pneumology, Angiology, and Intensive Care, University of Cologne, Germany (J-N.H., J.J.)
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Daniel Aeschbach
- Institute of Experimental Epileptology and Cognition Research (D.A.), University of Bonn Medical Center, Germany
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
| | - Eva-Maria Elmenhorst
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
- Institute for Occupational, Social and Environmental Medicine (E-M.E.), Medical Faculty, Rheinisch-Westfälische Technische Hochschule Aachen University, Germany
| | - Ulrike Herberg
- Department of Pediatric Cardiology (U.H.), Medical Faculty, Rheinisch-Westfälische Technische Hochschule Aachen University, Germany
| | - Alena Hess
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Moritz Schumann
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
- Department of Sports Medicine and Exercise Therapy, Institute of Human Movement Science and Health, Chemnitz University of Technology, Germany (M.S.)
| | - Tobias Kratz
- Department of Pediatric Cardiology (N.M., J.A.H., U.B., C.H., A.H., T.K., J.B.), University of Bonn Medical Center, Germany
| | - Jens Jordan
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
- Medical Faculty, University of Cologne, Albertus-Magnus-Platz, Cologne, Germany (J.J.)
- Department of Internal Medicine III, Division of Cardiology, Pneumology, Angiology, and Intensive Care, University of Cologne, Germany (J-N.H., J.J.)
| | - Johannes Breuer
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany (J.B., B.S., E.Z., M.G., B.D., W.B., M.S.)
| | - Jens Tank
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany (J.S., M.v.d.W., I.R. D.G., J.v.S., A.B., L-M.d.B., J-N.H., D.A., E-M.E., J.J., J.T.)
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Schulz A, Mittelmeier H, Wagenhofer L, Backhaus SJ, Lange T, Evertz R, Kutty S, Kowallick JT, Hasenfuß G, Schuster A. Assessment of the cardiac output at rest and during exercise stress using real-time cardiovascular magnetic resonance imaging in HFpEF-patients. Int J Cardiovasc Imaging 2024; 40:853-862. [PMID: 38236362 PMCID: PMC11052864 DOI: 10.1007/s10554-024-03054-6] [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: 11/30/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024]
Abstract
This methodological study aimed to validate the cardiac output (CO) measured by exercise-stress real-time phase-contrast cardiovascular magnetic resonance imaging (CMR) in patients with heart failure and preserved ejection fraction (HFpEF). 68 patients with dyspnea on exertion (NYHA ≥ II) and echocardiographic signs of diastolic dysfunction underwent rest and exercise stress right heart catheterization (RHC) and CMR within 24 h. Patients were diagnosed as overt HFpEF (pulmonary capillary wedge pressure (PCWP) ≥ 15mmHg at rest), masked HFpEF (PCWP ≥ 25mmHg during exercise stress but < 15mmHg at rest) and non-cardiac dyspnea. CO was calculated using RHC as the reference standard, and in CMR by the volumetric stroke volume, conventional phase-contrast and rest and stress real-time phase-contrast imaging. At rest, the CMR based CO showed good agreement with RHC with an ICC of 0.772 for conventional phase-contrast, and 0.872 for real-time phase-contrast measurements. During exercise stress, the agreement of real-time CMR and RHC was good with an ICC of 0.805. Real-time measurements underestimated the CO at rest (Bias:0.71 L/min) and during exercise stress (Bias:1.4 L/min). Patients with overt HFpEF had a significantly lower cardiac index compared to patients with masked HFpEF and with non-cardiac dyspnea during exercise stress, but not at rest. Real-time phase-contrast CO can be assessed with good agreement with the invasive reference standard at rest and during exercise stress. While moderate underestimation of the CO needs to be considered with non-invasive testing, the CO using real-time CMR provides useful clinical information and could help to avoid unnecessary invasive procedures in HFpEF patients.
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Affiliation(s)
- Alexander Schulz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Hannah Mittelmeier
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany
| | - Lukas Wagenhofer
- Institute of Biomedical Imaging, University of Technology Graz, Graz, Austria
| | - Sören J Backhaus
- Department of Cardiology, Campus Kerckhoff of the Justus-Liebig-University Giessen, Kerckhoff-Clinic, Bad Nauheim, Germany
| | - Torben Lange
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Ruben Evertz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Shelby Kutty
- Taussig Heart Center, Johns Hopkins Hospital and School of Medicine, Baltimore, MD, 21287, USA
| | - Johannes T Kowallick
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen University Medical Center Göttingen, Georg-August University, Göttingen, Germany
| | - Gerd Hasenfuß
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Andreas Schuster
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Robert-Koch-Str. 40, 37099, Göttingen, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
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Contijoch F, Rasche V, Seiberlich N, Peters DC. The future of CMR: All-in-one vs. real-time CMR (Part 2). J Cardiovasc Magn Reson 2024; 26:100998. [PMID: 38237901 PMCID: PMC11211235 DOI: 10.1016/j.jocmr.2024.100998] [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: 12/21/2023] [Accepted: 01/10/2024] [Indexed: 02/20/2024] Open
Abstract
Cardiac Magnetic Resonance (CMR) protocols can be lengthy and complex, which has driven the research community to develop new technologies to make these protocols more efficient and patient-friendly. Two different approaches to improving CMR have been proposed, specifically "all-in-one" CMR, where several contrasts and/or motion states are acquired simultaneously, and "real-time" CMR, in which the examination is accelerated to avoid the need for breathholding and/or cardiac gating. The goal of this two-part manuscript is to describe these two different types of emerging rapid CMR protocols. To this end, the vision of all-in-one and real-time imaging are described, along with techniques which have been devised and tested along the pathway of clinical implementation. The pros and cons of the different methods are presented, and the remaining open needs of each are detailed. Part 1 tackles the "All-in-One" approaches, and Part 2 focuses on the "Real-Time" approaches along with an overall summary of these emerging methods.
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Affiliation(s)
| | - Volker Rasche
- Ulm University Medical Center, Department of Internal Medicine II, Ulm, Germany
| | - Nicole Seiberlich
- Michigan Institute for Imaging Technology and Translation, Department of Radiology, University of Michigan, Ann Arbor, MI, USA
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Ludwig HC, Dreha-Kulaczewski S, Bock HC. Paediatric pineal region cysts: enigma or impaired neurofluid system? Childs Nerv Syst 2023; 39:3457-3466. [PMID: 37261536 PMCID: PMC10684616 DOI: 10.1007/s00381-023-06000-4] [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: 03/01/2023] [Accepted: 05/18/2023] [Indexed: 06/02/2023]
Abstract
PURPOSE Pineal region cysts (PCs) may affect the tectum and aqueduct and cause deep central vein congestion. Beside headaches, PC often causes a broad range of symptoms, leading to prolonged diagnosis and therapy. The aims of this study are to reveal parameters that might explain the ambiguity of the symptoms and to identify factors in association with the respiration-driven neurofluid system. METHODS This retrospective study included 28 paediatric patients (mean age 11.6 years) who received surgical treatment and 18 patients (mean age 11.3 years) who were followed conservatively. Symptoms, time to diagnosis, cyst size, ventricular indices, head circumference and postoperative outcome, were analysed. Four patients were investigated for CSF dynamics with real-time MRI. The mean follow-up time was 1.6 years. RESULTS The most common early onset symptoms were headaches (92%), blurred vision (42.8%), sleep disturbances (39.3%) and vertigo (32.1%). Tectum contact was observed in 82% of patients, and MRI examinations revealed that imaging flow void signals were absent in 32.1% of patients. The maximal cyst diameters were 13.7 × 15.6 mm (mean). Together with a postoperative flow void signal, 4 patients recovered their respiration-driven CSF aqueductal upward flow, which was not detectable preoperatively. After surgery the main symptoms improved. CONCLUSION Despite proximity to the aqueduct with frequently absent flow void signals, hydrocephalus was never detected. Data from real-time MRI depicted a reduced preoperative filling of the ventricular CSF compartments, indicating a diminished fluid preload, which recovered postoperatively.
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Affiliation(s)
- Hans C Ludwig
- Department of Neurosurgery, Division of Pediatric Neurosurgery, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
| | - Steffi Dreha-Kulaczewski
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Hans Christoph Bock
- Department of Neurosurgery, Division of Pediatric Neurosurgery, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
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DiCarlo AL, Haji-Valizadeh H, Passman R, Greenland P, McCarthy P, Lee DC, Kim D, Markl M. Assessment of Beat-To-Beat Variability in Left Atrial Hemodynamics Using Real Time Phase Contrast MRI in Patients With Atrial Fibrillation. J Magn Reson Imaging 2023; 58:763-771. [PMID: 36468562 PMCID: PMC10239789 DOI: 10.1002/jmri.28550] [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: 06/07/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hemodynamic assessment of left atrial (LA) flow using phase contrast MRI provides insight into thromboembolic risk in atrial fibrillation (AF). However, conventional flow imaging techniques are averaged over many heartbeats. PURPOSE To evaluate beat-to-beat variability and LA hemodynamics in patients with AF using real time phase contrast (RTPC) MRI. STUDY TYPE Prospective. SUBJECTS Thirty-five patients with history of AF (68 ± 10 years, nine female), 10 healthy controls (57 ± 19 years, four female). FIELD STRENGTH/SEQUENCE 5T, 2D RTPC with through-plane velocity-encoded gradient echo sequence and 4D flow MRI with three-directional velocity-encoded gradient echo sequence. ASSESSMENT RTPC was continuously acquired for a mid-LA slice in all subjects. 4D flow data were interpolated at the RTPC location and normally projected for comparison with RTPC. RR intervals extracted from RTPC were used to calculate heart rate variability (HRV = interquartile range over median × 100%). Patients were classified into low (<9.7%) and high (>9.7%) HRV groups. LA peak/mean velocity and stasis (%velocities < 5.8 cm/sec) were calculated from segmented 2D images. Variability in RTPC flow metrics was quantified by coefficient of variation (CV) over all cycles. STATISTICAL TESTS Pearson's correlation coefficient (r), Bland-Altman analysis, Kruskal-Wallis test. A P value < 0.05 was considered statistically significant. RESULTS RTPC and 4D flow measurements were strongly/significantly correlated for all hemodynamic parameters (R2 = 0.75-0.83) in controls. Twenty-four patients had low HRV (mean = 4 ± 2%) and 11 patients had high HRV (27 ± 9%). In patients, increased HRV was significantly correlated with CV of peak velocity (r = 0.67), mean velocity (r = 0.51), and stasis (r = 0.41). A stepwise decrease in peak/mean velocity and increase in stasis was observed when comparing controls vs. low HRV vs. high HRV groups. Mean velocity and stasis differences were significant for control vs. high HRV groups. CONCLUSIONS RTPC may be suitable for assessing the impact of HRV on hemodynamics and provide insight for AF management in highly arrhythmic patients. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Amanda L DiCarlo
- Department of Radiology, Northwestern University Feinberg School of Medicine
| | - Hassan Haji-Valizadeh
- Department of Radiology, Northwestern University Feinberg School of Medicine
- Department of Biomedical Engineering, Northwestern University McCormick School of Engineering
| | - Rod Passman
- Department of Cardiology, Northwestern University Feinberg School of Medicine
| | - Philip Greenland
- Department of Cardiology, Northwestern University Feinberg School of Medicine
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine
| | - Patrick McCarthy
- Department of Cardiothoracic Surgery, Northwestern University Feinberg School of Medicine
| | - Daniel C Lee
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine
| | - Daniel Kim
- Department of Radiology, Northwestern University Feinberg School of Medicine
- Department of Biomedical Engineering, Northwestern University McCormick School of Engineering
| | - Michael Markl
- Department of Radiology, Northwestern University Feinberg School of Medicine
- Department of Biomedical Engineering, Northwestern University McCormick School of Engineering
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Schulz A, Lange T, Evertz R, Kowallick JT, Hasenfuß G, Backhaus SJ, Schuster A. Sex-Specific Impairment of Cardiac Functional Reserve in HFpEF: Insights From the HFpEF Stress Trial. JACC. ADVANCES 2023; 2:100327. [PMID: 38938247 PMCID: PMC11198589 DOI: 10.1016/j.jacadv.2023.100327] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/06/2023] [Accepted: 02/28/2023] [Indexed: 06/29/2024]
Abstract
Background Heart failure with preserved ejection fraction (HFpEF) has been observed to have a twice as high prevalence in women compared to men with similar predisposing risk factors between both sexes. Objectives This study aimed to identify sex-specific pathophysiological features in HFpEF using rest and exercise stress right heart catheterization (RHC), echocardiography and cardiovascular magnetic resonance imaging (CMR). Methods Seventy-five patients with exertional dyspnea, preserved ejection fraction (EF) (≥50%), and signs of diastolic dysfunction on echocardiography were prospectively recruited in the HFpEF Stress Trial. Patients underwent RHC, echocardiography and CMR at rest and during exercise stress. Patients were diagnosed with HFpEF and noncardiac dyspnea according to RHC measurements. Results After exclusion, the final study cohort comprised 68 patients (females n = 44, males n = 24) with a mean age of 66.9 ± 9.7 years. Compared to men, women with HFpEF revealed lower right ventricular stroke volumes during exercise stress (females 38.1 vs males 50.4 mL/m2 BSA; P = 0.011). This was accompanied by a decreasing left atrial EF in women but not men comparing resting to exercise conditions (females -2.7% vs males 2.5%, P = 0.020) and impaired left ventricular filling (females 35.5 vs males 44.2 mL/m2 BSA, P = 0.017) in women with HFpEF during exercise stress. These sex-specific differences were not present in noncardiac dyspnea. Conclusions Women with HFpEF demonstrate sex-specific functional alterations of right ventricular, left atrial, and left ventricular function during exercise stress. This unique pathophysiology represents a sex-specific diagnostic target, which may allow early identification of women with HFpEF for future individualized therapeutic approaches.
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Affiliation(s)
- Alexander Schulz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Torben Lange
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Ruben Evertz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Johannes T. Kowallick
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
- University Medical Center Göttingen, Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany
| | - Gerd Hasenfuß
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Sören J. Backhaus
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Andreas Schuster
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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8
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Sun A, Zhao B, Zheng Y, Long Y, Wu P, Wang B, Li R, Wang H. Motion-resolved real-time 4D flow MRI with low-rank and subspace modeling. Magn Reson Med 2023; 89:1839-1852. [PMID: 36533875 DOI: 10.1002/mrm.29557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/01/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022]
Abstract
PURPOSE To develop a new motion-resolved real-time four-dimensional (4D) flow MRI method, which enables the quantification and visualization of blood flow velocities with three-directional flow encodings and volumetric coverage without electrocardiogram (ECG) synchronization and respiration control. METHODS An integrated imaging method is presented for real-time 4D flow MRI, which encompasses data acquisition, image reconstruction, and postprocessing. The proposed method features a specialized continuous ( k , t ) $$ \left(\mathbf{k},t\right) $$ -space acquisition scheme, which collects two sets of data (i.e., training data and imaging data) in an interleaved manner. By exploiting strong spatiotemporal correlation of 4D flow data, it reconstructs time-series images from highly-undersampled ( k , t ) $$ \left(\mathbf{k},t\right) $$ -space measurements with a low-rank and subspace model. Through data-binning-based postprocessing, it constructs a five-dimensional dataset (i.e., x-y-z-cardiac-respiratory), from which respiration-dependent flow information is further analyzed. The proposed method was evaluated in aortic flow imaging experiments with ten healthy subjects and two patients with atrial fibrillation. RESULTS The proposed method achieves 2.4 mm isotropic spatial resolution and 34.4 ms temporal resolution for measuring the blood flow of the aorta. For the healthy subjects, it provides flow measurements in good agreement with those from the conventional 4D flow MRI technique. For the patients with atrial fibrillation, it is able to resolve beat-by-beat pathological flow variations, which cannot be obtained from the conventional technique. The postprocessing further provides respiration-dependent flow information. CONCLUSION The proposed method enables high-resolution motion-resolved real-time 4D flow imaging without ECG gating and respiration control. It is able to resolve beat-by-beat blood flow variations as well as respiration-dependent flow information.
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Affiliation(s)
- Aiqi Sun
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Bo Zhao
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA.,Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas, USA
| | | | - Yuliang Long
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Peng Wu
- Philips Healthcare, Shanghai, China
| | - Bei Wang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Rui Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - He Wang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.,Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
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9
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Schuster A, Schulz A, Lange T, Evertz R, Hartmann F, Kowallick JT, Hellenkamp K, Uecker M, Seidler T, Hasenfuß G, Backhaus SJ. Concomitant latent pulmonary vascular disease leads to impaired global cardiac performance in heart failure with preserved ejection fraction. Eur J Heart Fail 2023; 25:322-331. [PMID: 36691723 DOI: 10.1002/ejhf.2781] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/05/2023] [Accepted: 01/15/2023] [Indexed: 01/25/2023] Open
Abstract
AIMS The REDUCE-LAP II trial demonstrated adverse outcomes after interatrial shunt device (IASD) placement in heart failure with preserved ejection fraction (HFpEF) attributed to latent pulmonary vascular disease (PVD). We hypothesized that exercise stress cardiovascular magnetic resonance (CMR) imaging could provide non-invasive characterization of cardiac and pulmonary physiology for improved patient selection. METHODS AND RESULTS The HFpEF-Stress trial prospectively enrolled 75 patients with exertional dyspnoea and diastolic dysfunction. Patients underwent rest and exercise stress right heart catheterization, echocardiography and CMR imaging. Pulmonary artery and capillary wedge pressures, cardiac index (CI) and pulmonary vascular resistance (PVR) were calculated. Latent PVD was defined as increased PVR ≥ 1.74 Wood units during exercise stress. CMR assessed long-axis strains (LAS) and filling volumes of all cardiac chambers. Right ventricular (RV) function was further quantified by stroke and peak flow volumes. Patients with latent PVD (n = 24) showed lower RV function (rest tricuspid annular plane systolic excursion, p = 0.010; stress RV LAS, p < 0.001) compared to patients without (n = 43). During exercise stress, RV stroke and peak flow volumes (p < 0.001) were reduced and led to impaired left atrial filling (p = 0.040) with a strong statistical trend to impaired ventricular (LV) filling (p = 0.098). This subsequently resulted in reduced LV-CI (p < 0.001) despite preserved LV systolic function (LV LAS p ≥ 0.255). The degree of RV dysfunction during exercise stress best predicted latent PVD (RV peak flow, area under the curve at rest 0.73 vs. stress 0.89, p = 0.004). CONCLUSIONS Latent PVD is a feature of HFpEF and is associated with impaired RV functional reserve, global diastolic filling and LV-CI. This can be quantified by CMR and used to identify patients likely to benefit from IASD implantation.
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Affiliation(s)
- Andreas Schuster
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.,School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Alexander Schulz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Torben Lange
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Ruben Evertz
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Finn Hartmann
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Johannes T Kowallick
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.,University Medical Center Göttingen (UMG), Institute for Diagnostic and Interventional Radiology, Göttingen, Germany
| | - Kristian Hellenkamp
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
| | - Martin Uecker
- German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.,University Medical Center Göttingen (UMG), Institute for Diagnostic and Interventional Radiology, Göttingen, Germany.,Institute of Biomedical Imaging, Graz University of Technology, Graz, Austria
| | - Tim Seidler
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Gerd Hasenfuß
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Sören J Backhaus
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.,School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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10
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Kollmeier JM, Gürbüz-Reiss L, Sahoo P, Badura S, Ellebracht B, Keck M, Gärtner J, Ludwig HC, Frahm J, Dreha-Kulaczewski S. Deep breathing couples CSF and venous flow dynamics. Sci Rep 2022; 12:2568. [PMID: 35173200 PMCID: PMC8850447 DOI: 10.1038/s41598-022-06361-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/24/2022] [Indexed: 11/30/2022] Open
Abstract
Venous system pathologies have increasingly been linked to clinically relevant disorders of CSF circulation whereas the exact coupling mechanisms still remain unknown. In this work, flow dynamics of both systems were studied using real-time phase-contrast flow MRI in 16 healthy subjects during normal and forced breathing. Flow evaluations in the aqueduct, at cervical level C3 and lumbar level L3 for both the CSF and venous fluid systems reveal temporal modulations by forced respiration. During normal breathing cardiac-related flow modulations prevailed, while forced breathing shifted the dominant frequency of both CSF and venous flow spectra towards the respiratory component and prompted a correlation between CSF and venous flow in the large vessels. The average of flow magnitude of CSF was increased during forced breathing at all spinal and intracranial positions. Venous flow in the large vessels of the upper body decreased and in the lower body increased during forced breathing. Deep respiration couples interdependent venous and brain fluid flow—most likely mediated by intrathoracic and intraabdominal pressure changes. Further insights into the driving forces of CSF and venous circulation and their correlation will facilitate our understanding how the venous system links to intracranial pressure regulation and of related forms of hydrocephalus.
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Affiliation(s)
- Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, 37077, Göttingen, Germany
| | - Lukas Gürbüz-Reiss
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Prativa Sahoo
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Simon Badura
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Ben Ellebracht
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Mathilda Keck
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jutta Gärtner
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Hans-Christoph Ludwig
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, 37077, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany.
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11
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Whittaker JR, Fasano F, Venzi M, Liebig P, Gallichan D, Möller HE, Murphy K. Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast. Front Neurosci 2022; 15:795749. [PMID: 35110991 PMCID: PMC8802674 DOI: 10.3389/fnins.2021.795749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
The pulsatility of blood flow through cerebral arteries is clinically important, as it is intrinsically associated with cerebrovascular health. In this study we outline a new MRI approach to measuring the real-time pulsatile flow in cerebral arteries, which is based on the inflow phenomenon associated with fast gradient-recalled-echo acquisitions. Unlike traditional phase-contrast techniques, this new method, which we dub dynamic inflow magnitude contrast (DIMAC), does not require velocity-encoding gradients as sensitivity to flow velocity is derived purely from the inflow effect. We achieved this using a highly accelerated single slice EPI acquisition with a very short TR (15 ms) and a 90° flip angle, thus maximizing inflow contrast. We simulate the spoiled GRE signal in the presence of large arteries and perform a sensitivity analysis. The sensitivity analysis demonstrates that in the regime of high inflow contrast, DIMAC shows much greater sensitivity to flow velocity over blood volume changes. We support this theoretical prediction with in-vivo data collected in two separate experiments designed to demonstrate the utility of the DIMAC signal contrast. We perform a hypercapnia challenge experiment in order to experimentally modulate arterial tone within subjects, and thus modulate the arterial pulsatile flow waveform. We also perform a thigh-cuff release challenge, designed to induce a transient drop in blood pressure, and demonstrate that the continuous DIMAC signal captures the complex transient change in the pulsatile and non-pulsatile components of flow. In summary, this study proposes a new role for a well-established source of MR image contrast and demonstrates its potential for measuring both steady-state and dynamic changes in arterial tone.
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Affiliation(s)
- Joseph R. Whittaker
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | | | - Marcello Venzi
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | | | | | - Harald E. Möller
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Kevin Murphy
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
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12
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Kollmeier JM, Kalentev O, Klosowski J, Voit D, Frahm J. Velocity vector reconstruction for real-time phase-contrast MRI with radial Maxwell correction. Magn Reson Med 2021; 87:1863-1875. [PMID: 34850452 DOI: 10.1002/mrm.29108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/04/2021] [Accepted: 11/12/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE To develop an auto-calibrated image reconstruction for highly accelerated multi-directional phase-contrast (PC) MRI that compensates for (1) reconstruction instabilities occurring for phase differences near ± π and (2) phase errors by concomitant magnetic fields that differ for individual radial spokes. THEORY AND METHODS A model-based image reconstruction for real-time PC MRI based on nonlinear inversion is extended to multi-directional flow by exploiting multiple flow-encodings for the estimation of velocity vectors. An initial smoothing constraint during iterative optimization is introduced to resolve the ambiguity of the solution space by penalizing phase wraps. Maxwell terms are considered as part of the signal model on a line-by-line basis to address phase errors by concomitant magnetic fields. The reconstruction methods are evaluated using simulated data and cross-sectional imaging of a rotating-disc, as well as in vivo for the aortic arch and cervical spinal canal at 3T. RESULTS Real-time three-directional velocity mapping in the aortic arch is achieved at 1.8 × 1.8 × 6 mm3 spatial and 60 ms temporal resolution. Artificial phase wraps are avoided in all cases using the smoothness constraint. Inter-spoke differences of concomitant magnetic fields are effectively compensated for by the model-based image reconstruction with integrated radial Maxwell correction. CONCLUSION Velocity vector reconstructions based on nonlinear inversion allow for high degrees of radial data undersampling paving the way for multi-directional PC MRI in real time. Whether a spoke-wise treatment of Maxwell terms is required or a computationally cheaper frame-wise approach depends on the individual application.
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Affiliation(s)
- Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Oleksandr Kalentev
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jakob Klosowski
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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13
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Haji-Valizadeh H, Guo R, Kucukseymen S, Paskavitz A, Cai X, Rodriguez J, Pierce P, Goddu B, Kim D, Manning W, Nezafat R. Highly accelerated free-breathing real-time phase contrast cardiovascular MRI via complex-difference deep learning. Magn Reson Med 2021; 86:804-819. [PMID: 33720465 DOI: 10.1002/mrm.28750] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/18/2021] [Accepted: 02/05/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE To develop and evaluate a real-time phase contrast (PC) MRI protocol via complex-difference deep learning (DL) framework. METHODS DL used two 3D U-nets to separately filter aliasing artifact from radial real-time velocity-compensated and complex-difference images. U-nets were trained with synthetic real-time PC generated from electrocardiograph (ECG) -gated, breath-hold, segmented PC (ECG-gated segmented PC) acquired at the ascending aorta of 510 patients. In 21 patients, free-breathing, ungated real-time (acceleration rate = 28.8) and ECG-gated segmented (acceleration rate = 2) PC were prospectively acquired at the ascending aorta. Hemodynamic parameters (cardiac output [CO], stroke volume [SV], and mean velocity at peak systole [peak mean velocity]) were measured for ECG-gated segmented and DL-filtered synthetic real-time PC and compared using Bland-Altman and linear regression analyses. Additionally, hemodynamic parameters were quantified from DL-filtered, compressed-sensing (CS) -reconstructed, and gridding reconstructed prospective real-time PC and compared to ECG-gated segmented PC. RESULTS Synthetic real-time PC with DL showed strong correlation (R > 0.98) and good agreement with ECG-gated segmented PC for quantified hemodynamic parameters (mean-difference: CO = -0.3 L/min, SV = -4.3 mL, peak mean velocity = -2.3 cm/s). On average, DL required 0.39 s/frame to filter prospective real-time PC, which was 4.6-fold faster than CS. Compared to CS, DL showed superior correlation, tighter limits of agreement (LOAs), better bias for peak mean velocity, and worse bias for CO and SV. Compared to gridding, DL showed similar correlation, tighter LOAs for CO and SV, similar bias for CO, and worse bias for SV and peak mean velocity. CONCLUSION The complex-difference DL framework accelerated real-time PC-MRI by nearly 28-fold, enabling rapid free-running real-time assessment of flow hemodynamics.
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Affiliation(s)
- Hassan Haji-Valizadeh
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Rui Guo
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Selcuk Kucukseymen
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Amanda Paskavitz
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Xiaoying Cai
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Siemens Medical Solutions USA, Inc., Boston, Massachusetts, USA
| | - Jennifer Rodriguez
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Patrick Pierce
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Beth Goddu
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Kim
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Warren Manning
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Nezafat
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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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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Validation of non-contrast multiple overlapping thin-slab 4D-flow cardiac magnetic resonance imaging. Magn Reson Imaging 2020; 74:223-231. [PMID: 33035638 DOI: 10.1016/j.mri.2020.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/31/2020] [Accepted: 10/04/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Cardiac magnetic resonance (CMR) flow quantification is typically performed using 2D phase-contrast (PC) imaging of a plane perpendicular to flow. 3D-PC imaging (4D-flow) allows offline quantification anywhere in a thick slab, but is often limited by suboptimal signal, potentially alleviated by contrast enhancement. We developed a non-contrast 4D-flow sequence, which acquires multiple overlapping thin slabs (MOTS) to minimize signal loss, and hypothesized that it could improve image quality, diagnostic accuracy, and aortic flow measurements compared to non-contrast single-slab approach. METHODS We prospectively studied 20 patients referred for transesophageal echocardiography (TEE), who underwent CMR (GE, 3 T). 2D-PC images of the aortic valve and three 4D-flow datasets covering the heart were acquired, including single-slab, pre- and post-contrast, and non-contrast MOTS. Each 4D-flow dataset was interpreted blindly for ≥moderate valve disease and compared to TEE. Flow visualization through each valve was scored (0 to 4), and aortic-valve flow measured on each 4D-flow dataset and compared to 2D-PC reference. RESULTS Diagnostic quality visualization was achieved with the pre- and post-contrast 4D-flow acquisitions in 25% and 100% valves, respectively (scores 0.9 ± 1.1 and 3.8 ± 0.5), and in 58% with the non-contrast MOTS (1.6 ± 1.1). Accuracy of detection of valve disease was 75%, 92% and 82%, respectively. Aortic flow measurements were possible in 53%, 95% and in 89% patients, respectively. The correlation between pre-contrast single-slab measurements and 2D-PC reference was weak (r = 0.21), but improved with both contrast enhancement (r = 0.71) and with MOTS (r = 0.67). CONCLUSIONS Although non-contrast MOTS 4D-flow improves valve function visualization and diagnostic accuracy, a significant proportion of valves cannot be accurately assessed. However, aortic flow measurements using non-contrast MOTS is feasible and reaches similar accuracy to that of contrast-enhanced 4D-flow.
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16
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Rich A, Gregg M, Jin N, Liu Y, Potter L, Simonetti O, Ahmad R. CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA). Magn Reson Med 2020; 83:2015-2025. [PMID: 31721303 PMCID: PMC7059985 DOI: 10.1002/mrm.28059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 08/30/2019] [Accepted: 10/10/2019] [Indexed: 11/10/2022]
Abstract
PURPOSE To develop a variable density Cartesian sampling method that allows retrospective adjustment of temporal resolution for dynamic MRI applications and to validate it in real-time phase contrast MRI (PC-MRI). THEORY AND METHODS The proposed method, called CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA), begins by producing a sequence of phase encoding indices based on the golden ratio increment. Then, variable density is introduced by nonlinear stretching of the indices. Finally, the elements of the resulting sequence are rounded up to the nearest integer. The performance of CAVA is evaluated using PC-MRI data from a pulsatile flow phantom and real-time, free-breathing data from ten healthy volunteers. RESULTS CAVA enabled image recovery at various temporal resolutions that were selected retrospectively. For the pulsatile flow phantom, image quality and flow quantification accuracy from CAVA were comparable to that from another pseudo-random sampling pattern with fixed temporal resolution. In addition, flow quantification results based on CAVA were in good agreement with a breath-held segmented acquisition. CONCLUSIONS By allowing retrospective binning of the MRI data, CAVA provides an avenue to retrospectively adjust the temporal resolution of PC-MRI.
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Affiliation(s)
- Adam Rich
- Biomedical Engineering, The Ohio State University, Columbus OH, USA
| | - Michael Gregg
- Biomedical Engineering, The Ohio State University, Columbus OH, USA
- Electrical and Computer Engineering, The Ohio State University, Columbus OH, USA
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA Inc., Columbus OH USA
| | - Yingmin Liu
- Davis Heart & Lung Research Institute, The Ohio State University, Columbus OH, USA
| | - Lee Potter
- Electrical and Computer Engineering, The Ohio State University, Columbus OH, USA
| | - Orlando Simonetti
- Davis Heart & Lung Research Institute, The Ohio State University, Columbus OH, USA
- Internal Medicine, The Ohio State University, Columbus OH, USA
- Radiology, The Ohio State University, Columbus OH, USA
| | - Rizwan Ahmad
- Biomedical Engineering, The Ohio State University, Columbus OH, USA
- Electrical and Computer Engineering, The Ohio State University, Columbus OH, USA
- Davis Heart & Lung Research Institute, The Ohio State University, Columbus OH, USA
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17
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Measurement of Tongue Tip Velocity from Real-Time MRI and Phase-Contrast Cine-MRI in Consonant Production. J Imaging 2020; 6:jimaging6050031. [PMID: 34460733 PMCID: PMC8321019 DOI: 10.3390/jimaging6050031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 11/17/2022] Open
Abstract
We evaluate velocity of the tongue tip with magnetic resonance imaging (MRI) using two independent approaches. The first one consists in acquisition with a real-time technique in the mid-sagittal plane. Tracking of the tongue tip manually and with a computer vision method allows its trajectory to be found and the velocity to be calculated as the derivative of the coordinate. We also propose to use another approach—phase contrast MRI—which enables velocities of the moving tissues to be measured directly. We recorded the sound simultaneously with the MR acquisition which enabled us to make conclusions regarding the relation between the movements and the sound. We acquired the data from two French-speaking subjects articulating /tata/. The results of both methods are in qualitative agreement and are consistent with other reviewer techniques used for evaluation of the tongue tip velocity.
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18
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Kollmeier JM, Tan Z, Joseph AA, Kalentev O, Voit D, Merboldt KD, Frahm J. Real-time multi-directional flow MRI using model-based reconstructions of undersampled radial FLASH - A feasibility study. NMR IN BIOMEDICINE 2019; 32:e4184. [PMID: 31580524 DOI: 10.1002/nbm.4184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/12/2019] [Accepted: 08/15/2019] [Indexed: 06/10/2023]
Abstract
The purpose of this work was to develop an acquisition and reconstruction technique for two- and three-directional (2d and 3d) phase-contrast flow MRI in real time. A previous real-time MRI technique for one-directional (1d) through-plane flow was extended to 2d and 3d flow MRI by introducing in-plane flow sensitivity. The method employs highly undersampled radial FLASH sequences with sequential acquisitions of two or three flow-encoding datasets and one flow-compensated dataset. Echo times are minimized by merging the waveforms of flow-encoding and radial imaging gradients. For each velocity direction individually, model-based reconstructions by regularized nonlinear inversion jointly estimate an anatomical image, a set of coil sensitivities and a phase-contrast velocity map directly. The reconstructions take advantage of a dynamic phase reference obtained by interpolating consecutive flow-compensated acquisitions. Validations include pulsatile flow phantoms as well as in vivo studies of the human aorta at 3 T. The proposed method offers cross-sectional 2d and 3d flow MRI of the human aortic arch at 53 and 67 ms resolution, respectively, without ECG synchronization and during free breathing. The in-plane resolution was 1.5 × 1.5 mm2 and the slice thickness 6 mm. In conclusion, real-time multi-directional flow MRI offers new opportunities to study complex human blood flow without the risk of combining differential phase (i.e., velocity) information from multiple heartbeats as for ECG-gated data. The method would benefit from a further reduction of acquisition time and accelerated computing to allow for extended clinical trials.
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Affiliation(s)
- Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Zhengguo Tan
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Oleksandr Kalentev
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - K Dietmar Merboldt
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
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19
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Voit D, Kalentev O, Frahm J. Body coil reference for inverse reconstructions of multi-coil data-the case for real-time MRI. Quant Imaging Med Surg 2019; 9:1815-1819. [PMID: 31867235 DOI: 10.21037/qims.2019.08.14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Real-time magnetic resonance imaging (MRI) or model-based MRI reconstructions of parametric maps require the solution of an ill-posed nonlinear inverse problem. Respective algorithms, e.g., the iteratively regularized Gauss-Newton method, implicitly combine datasets from multiple receive coils. Because these local coils may exhibit complex sensitivity profiles with rather different phase offsets, the numerical optimization may lead to phase singularities which in turn cause "black holes" in magnitude images. The purpose of this work is to develop a method for inverse reconstructions of multi-coil MRI data which avoids the generation of such spatially selective phase singularities. It is proposed to use volumetric body coil data and start the iterative reconstruction of multi-coil data with a reference image which offers proper phase information. In more detail, inverse reconstructions of multi-coil data are initialized with a complex "seed" image which is obtained by a Fast Fourier Transform (FFT) reconstruction of data from a single body coil element. This is accomplished at no additional cost as only very few body coil scans with identical conditions as the multi-coil acquisitions are needed as part of the regular prep scan period. The method is evaluated for anatomical real-time MRI and model-based phase-contrast flow MRI in real-time at 3 T. The proposed method overcomes phase singularities in all cases for arbitrary sets of receive coils. In conclusion, the automatic use of a single body coil reference image is simple, robust, and further improves the reliability of advanced MRI reconstructions from multi-coil data.
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Affiliation(s)
- Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Oleksandr Kalentev
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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20
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Iltis PW, Heyne M, Frahm J, Voit D, Joseph A, Atlas L. Simultaneous dual-plane, real-time magnetic resonance imaging of oral cavity movements in advanced trombone players. Quant Imaging Med Surg 2019; 9:976-984. [PMID: 31367552 DOI: 10.21037/qims.2019.05.14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background This paper describes the use of real-time magnetic resonance imaging to simultaneously obtain magnetic resonance imaging (MRI) videos in both a sagittal and coronal plane during the performance of a musical exercise in five advanced trombone players. Methods Dual-slice recordings were implemented in a frame-interleaved manner with 20 ms acquisitions per frame to achieve two interleaved videos at a rate of 25 frames per second. A customized MATLAB toolkit was used for the extraction of line profiles from MRI videos to quantify tongue movements associated with exercise performance from both perspectives. Results Across all subjects, the analyses revealed precise coupling of vertical movements of the dorsal tongue surface (DTS), viewed from a sagittal perspective, with reduction in the vertical and horizontal dimensions of the air channel formed between the DTS and the hard palate, viewed from a coronal perspective. The cross-correlation between these movements was very strong (mean R=0.967). Conclusions These results demonstrate the unique utility of this dual-slice technology in describing the coordination of complex tongue movements occurring in two planes (i.e., three directions) simultaneously, lending a deeper understanding of lingual motor control during trombone performance.
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Affiliation(s)
- Peter W Iltis
- Department of Kinesiology, Gordon College, Wenham, MA, USA
| | - Matthias Heyne
- College of Health & Rehabilitation Sciences: Sargent College, Boston University, Boston, MA, USA
| | - Jens Frahm
- MRI Research Group, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Voit
- MRI Research Group, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Arun Joseph
- MRI Research Group, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Lian Atlas
- Department of Kinesiology, Gordon College, Wenham, MA, USA
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21
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Burke CJ, Walter WR, Gyftopoulos S, Pham H, Baron S, Gonzalez-Lomas G, Vigdorchik JM, Youm T. Real-Time Assessment of Femoroacetabular Motion Using Radial Gradient Echo Magnetic Resonance Arthrography at 3 Tesla in Routine Clinical Practice: A Pilot Study. Arthroscopy 2019; 35:2366-2374. [PMID: 31395172 DOI: 10.1016/j.arthro.2019.02.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/22/2019] [Accepted: 02/28/2019] [Indexed: 02/02/2023]
Abstract
PURPOSE To compare femoroacetabular motion in a series of consecutive symptomatic patients with hip pain throughout the range of motion of the hip using a real-time radial gradient echo (GRE) sequence in addition to the routine hip protocol sequences for magnetic resonance (MR) arthrographic assessment of patients with and without clinical femoroacetabular impingement (FAI) syndrome. In particular, we sought to assess whether the additional dynamic sequence could differentiate between patients with and without a positive physical exam maneuver for FAI syndrome. METHODS Patients with hip pain referred for conventional hip MR arthrogram including those with and without a positive physical exam maneuver for FAI syndrome were imaged using routine hip MR arthrogram protocol and an additional real-time radial 2-dimensional GRE acquisition at 3 Tesla in an axial oblique plane with continuous scanning of a 9 mm thick slice through the center of the femoral head-neck axis. Patients who were unable to move through the range of motion were excluded (n = 3). Patients with acetabular dysplasia (defined by a lateral center-edge angle [CEA] of 20°) were also excluded, as were patients had Kellgren and Lawrence scores of > 0. The real-time cine sequence was acquired with the patient actively moving through neutral, flexion, flexion-abduction external-rotation, and flexion-adduction internal rotation (FADIR) positions aiming for 40° of abduction, then 25° of adduction at 80° to 90° flexion. Due to the placement of the coil over the hip, a true FADIR was precluded. Images were evaluated independently by 2 musculoskeletal radiologists measuring the joint space in the anterior, central, and posterior positions at each point during range of motion for femoroacetabular cortical space (FACS). Anterior FACS narrowing was calculated as the ratio of joint space in FADIR:neutral position, with lower ratios indicating greater narrowing. Static metrics including alpha angle, CEA, grade of cartilage loss according the Outerbridge classification, and patient demographics were also recorded. RESULTS Twenty-two painful hips in 22 patients (11 males and 11 females) with mean age 36 years (range, 15-67) were included. Twelve patients had a positive physical exam maneuver for FAI syndrome. The time to perform the dynamic sequence was 3 to 6 minutes. Interobserver agreement was strong, with intraclass correlation 0.91 and concordance correlation 0.90. According to results from both readers, patients with impingement on clinical exam had significantly lower anterior FACS ratios compared with those without clinical impingement (reader 1: 0.39 ± 0.10 vs 0.69 ± 0.20, P = .001; reader 2: 0.36 ± 0.07 vs 0.70 ± 0.17, P < .001). Decreased anterior FACS ratio was found to be significantly correlated to increased alpha angle by both readers (reader 1: R = -0.63, P = .002; reader 2: R = -0.67, P = .001) but not significantly correlated to CEA (reader 1: R = 0.13, P = .561; reader 2: R = 0.20, P = .378) or cartilage loss (reader 1: R = 0.03, P = .885; reader 2: R = -0.06, P = .784). Both readers found patients with an anterior FACS ratio of 1/2 to have significantly higher mean alpha angle (reader 1: 62.88 vs 52.79, P = .038; reader 2: 63.50 vs 50.58, P = .006); however, there were no significant differences in cartilage loss (reader 1: P = .133; reader 2: P = .882) or CEA (reader 1: P = .340; reader 2: P = .307). CONCLUSIONS A dynamic radial 2-dimensional-GRE sequence can be added to standard hip MR arthrogram protocols in <6 minutes, allowing assessment of dynamic femoroacetabular motion with strong interreader agreement. Patients with impingement on clinical exam had significantly lower anterior FACS ratios between FADIR and neutral positions, compared with those without clinical impingement. LEVEL OF EVIDENCE Level III, comparative diagnostic investigation.
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Affiliation(s)
- Christopher J Burke
- Department of Radiology, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A..
| | - William R Walter
- Department of Radiology, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
| | - Soterios Gyftopoulos
- Department of Radiology, Division of Musculoskeletal Radiology, Center for Musculoskeletal Care, NYU Langone Medical Center, New York, New York, U.S.A
| | - Hien Pham
- Department of Orthopaedic Surgery, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
| | - Samuel Baron
- Department of Orthopaedic Surgery, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
| | - Guillem Gonzalez-Lomas
- Department of Orthopaedic Surgery, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
| | - Jonathan M Vigdorchik
- Department of Orthopaedic Surgery, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
| | - Thomas Youm
- Department of Orthopaedic Surgery, NYU Langone Health, Langone Orthopedic Hospital, New York, New York, U.S.A
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Abstract
Sleep is a behavioral phenomenon conserved among mammals and some invertebrates, yet the biological functions of sleep are still being elucidated. In humans, sleep time becomes shorter, more fragmented, and of poorer quality with advancing age. Epidemiologically, the development of age-related neurodegenerative diseases such as Alzheimer's and Parkinson's disease is associated with pronounced sleep disruption, whereas emerging mechanistic studies suggest that sleep disruption may be causally linked to neurodegenerative pathology, suggesting that sleep may represent a key therapeutic target in the prevention of these conditions. In this review, we discuss the physiology of sleep, the pathophysiology of neurodegenerative disease, and the current literature supporting the relationship between sleep, aging, and neurodegenerative disease.
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Affiliation(s)
- Thierno M Bah
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - James Goodman
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA.
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA.
- Veterans Integrated Service Network 20 Mental Illness Research, Education and Clinical Center, Puget Sound Health Care System, Mail Stop 116-MIRECC, 1660 South Columbian Way, Seattle, Washington, 98108, USA.
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.
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23
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Aktas G, Kollmeier JM, Joseph AA, Merboldt KD, Ludwig HC, Gärtner J, Frahm J, Dreha-Kulaczewski S. Spinal CSF flow in response to forced thoracic and abdominal respiration. Fluids Barriers CNS 2019; 16:10. [PMID: 30947716 PMCID: PMC6449937 DOI: 10.1186/s12987-019-0130-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/27/2019] [Indexed: 11/15/2022] Open
Abstract
Background Respiration-induced pressure changes represent a powerful driving force of CSF dynamics as previously demonstrated using flow-sensitive real-time magnetic resonance imaging (MRI). The purpose of the present study was to elucidate the sensitivity of CSF flow along the spinal canal to forced thoracic versus abdominal respiration. Methods Eighteen subjects without known illness were studied using real-time phase-contrast flow MRI at 3 T in the aqueduct and along the spinal canal at levels C3, Th1, Th8 and L3. Subjects performed a protocol of forced breathing comprising four cycles of 2.5 s inspiration and 2.5 s expiration. Results The quantitative results for spinal CSF flow rates and volumes confirm previous findings of an upward movement during forced inspiration and reversed downward flow during subsequent exhalation—for both breathing types. However, the effects were more pronounced for abdominal than for thoracic breathing, in particular at spinal levels Th8 and L3. In general, CSF net flow volumes were very similar for both breathing conditions pointing upwards in all locations. Conclusions Spinal CSF dynamics are sensitive to varying respiratory performances. The different CSF flow volumes in response to deep thoracic versus abdominal breathing reflect instantaneous adjustments of intrathoracic and intraabdominal pressure, respectively. Real-time MRI access to CSF flow in response to defined respiration patterns will be of clinical importance for patients with disturbed CSF circulation like hydrocephalus, pseudotumor cerebri and others. Electronic supplementary material The online version of this article (10.1186/s12987-019-0130-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gökmen Aktas
- School of Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Klaus-Dietmar Merboldt
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Hans-Christoph Ludwig
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jutta Gärtner
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany.
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24
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Wilke M, Dreha-Kulaczewski S. Aktuelle Techniken der Magnetresonanztomographie in der Neuropädiatrie. Monatsschr Kinderheilkd 2019. [DOI: 10.1007/s00112-019-0656-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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Aldweib N, Farah V, Biederman RWW. Clinical Utility of Cardiac Magnetic Resonance Imaging in Pericardial Diseases. Curr Cardiol Rev 2018; 14:200-212. [PMID: 29921208 PMCID: PMC6131401 DOI: 10.2174/1573403x14666180619104515] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 12/18/2022] Open
Abstract
Background: Pericardial diseases are relatively common in clinical practice and encountered in various clinical settings with consequent significant morbidity and mortality. However, the diagnosis as well as management can be complex and challenging, as the clinical presentation is usually non-specific. Therefore, there is an increasing role for Cardiac Magnetic Resonance Imaging (CMR) as an imaging tool to facilitate the diagnosis of pericardial diseases. Conclusion: Herein we describe conventional and unique CMR approaches to provide an increased non-invasive understanding of the pericardium in health and disease including a novel method to diagnose constrictive pericarditis via radio-frequency tissue tagging by defining unique visceral-parietal adherence patterns easily learned by the cardiologist and radiologist.
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Affiliation(s)
- Nael Aldweib
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
| | - Victor Farah
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
| | - Robert W W Biederman
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
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26
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Maier IL, Hofer S, Joseph AA, Merboldt KD, Tan Z, Schregel K, Knauth M, Bähr M, Psychogios MN, Liman J, Frahm J. Carotid artery flow as determined by real-time phase-contrast flow MRI and neurovascular ultrasound: A comparative study of healthy subjects. Eur J Radiol 2018; 106:38-45. [PMID: 30150049 DOI: 10.1016/j.ejrad.2018.07.011] [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: 08/05/2017] [Revised: 04/02/2018] [Accepted: 07/11/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND The assessment of carotid artery flow by neurovascular ultrasound (nvUS) can be complemented by real-time phase-contrast (RT-PC) flow MRI which apart from quantitative flow parameters offers velocity distributions across the entire vessel lumen. MATERIALS AND METHODS The feasibility and diagnostic potential of RT-PC flow MRI was evaluated in 20 healthy volunteers in comparison to conventional nvUS. RT-PC flow MRI at 40 ms temporal resolution and 0.8 mm in-plane resolution resulted in velocity maps with low phase noise and high spatiotemporal accuracy by exploiting respective advances of a recent nonlinear inverse model-based reconstruction. Peak-systolic velocities (PSV), end-diastolic velocities (EDV), flow volumes and comprehensive velocity profiles were determined in the common, internal and external carotid artery on both sides. RESULTS Flow characteristics such as pulsatility and individual abnormalities shown on nvUS could be reproduced and visualized in detail by RT-PC flow MRI. PSV to EDV differences revealed good agreement between both techniques, mean PSV and EDV were significantly lower and flow volumes were higher for MRI. CONCLUSION Our findings suggest that RT-PC flow MRI adds to clinical diagnostics, e.g. by alterations of dynamic velocity distributions in patients with carotid stenosis. Lower PSV and EDV values than for nvUS mainly reflect the longer MRI acquisition time which attenuates short peak velocities, while higher flow volumes benefit from a proper assessment of the true vessel lumen.
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Affiliation(s)
- Ilko L Maier
- Department of Neurology, University Medical Center Göttingen, Germany.
| | - Sabine Hofer
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Germany.
| | - K Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
| | - Zhengguo Tan
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
| | - Katharina Schregel
- Department of Neuroradiology, University Medical Center Göttingen, Germany; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Michael Knauth
- Department of Neuroradiology, University Medical Center Göttingen, Germany.
| | - Mathias Bähr
- Department of Neurology, University Medical Center Göttingen, Germany.
| | | | - Jan Liman
- Department of Neurology, University Medical Center Göttingen, Germany.
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Germany.
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27
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Dreha-Kulaczewski S, Konopka M, Joseph AA, Kollmeier J, Merboldt KD, Ludwig HC, Gärtner J, Frahm J. Respiration and the watershed of spinal CSF flow in humans. Sci Rep 2018; 8:5594. [PMID: 29618801 PMCID: PMC5884798 DOI: 10.1038/s41598-018-23908-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/15/2018] [Indexed: 11/09/2022] Open
Abstract
The dynamics of human CSF in brain and upper spinal canal are regulated by inspiration and connected to the venous system through associated pressure changes. Upward CSF flow into the head during inspiration counterbalances venous flow out of the brain. Here, we investigated CSF motion along the spinal canal by real-time phase-contrast flow MRI at high spatial and temporal resolution. Results reveal a watershed of spinal CSF dynamics which divides flow behavior at about the level of the heart. While forced inspiration prompts upward surge of CSF flow volumes in the entire spinal canal, ensuing expiration leads to pronounced downward CSF flow, but only in the lower canal. The resulting pattern of net flow volumes during forced respiration yields upward CSF motion in the upper and downward flow in the lower spinal canal. These observations most likely reflect closely coupled CSF and venous systems as both large caval veins and their anastomosing vertebral plexus react to respiration-induced pressure changes.
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Affiliation(s)
- Steffi Dreha-Kulaczewski
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, 37075, Göttingen, Germany.
| | - Mareen Konopka
- School of Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Jost Kollmeier
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Klaus-Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Hans-Christoph Ludwig
- Department of Neurosurgery, Division of Pediatric Neurosurgery, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
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28
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Burke CJ, Kaplan D, Block T, Chang G, Jazrawi L, Campbell K, Alaia M. Clinical Utility of Continuous Radial Magnetic Resonance Imaging Acquisition at 3 T in Real-time Patellofemoral Kinematic Assessment: A Feasibility Study. Arthroscopy 2018; 34:726-733. [PMID: 29273250 PMCID: PMC6080599 DOI: 10.1016/j.arthro.2017.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 02/02/2023]
Abstract
PURPOSE To compare patellar instability with magnetic resonance imaging analysis using continuous real-time radial gradient-echo (GRE) imaging in the assessment of symptomatic patients and asymptomatic subjects. METHODS Symptomatic patients with suspected patellofemoral maltracking and asymptomatic volunteers were scanned in real time by a radial 2-dimensional GRE sequence at 3 T in axial orientation at the patella level through a range of flexion-extension. The degree of lateral maltracking, as well as the associated tibial tubercle-trochlear groove distance and trochlea depth, was measured. Patellar lateralization was categorized as normal (≤2 mm), mild (>2 to ≤5 mm), moderate (>5 to ≤10 mm), or severe (>10 mm). The patellofemoral cartilage was also assessed according to the modified Outerbridge grading system. RESULTS The study included 20 symptomatic patients (13 women and 7 men; mean age, 36 ± 12.8 years) and 10 asymptomatic subjects (3 women and 7 men; mean age, 33.1 years). The mean time to perform the dynamic component ranged from 3 to 7 minutes. Lateralization in the symptomatic group was normal in 10 patients, mild in 1, moderate in 8, and severe in 1. There was no lateral tracking greater than 3 mm in the volunteer group. Lateral maltracking was significantly higher in symptomatic patients than in asymptomatic subjects (4.4 ± 3.7 mm vs 1.5 ± 0.71 mm, P = .007). Lateral tracking significantly correlated with tibial tubercle-trochlear groove distance (r = 0.48, P = .006). There was excellent agreement on lateral tracking between the 2 reviewers (intraclass correlation coefficient, 0.979; 95% confidence interval, 0.956-0.990). CONCLUSIONS The inclusion of a dynamic radial 2-dimensional GRE sequence is a rapid and easily performed addition to the standard magnetic resonance imaging protocol and allows dynamic quantitative assessment of patellar instability and lateral maltracking in symptomatic patients. With a paucity of reported data using this technique confirming that these results reach clinical significance, future work is required to determine how much lateral tracking is clinically significant. LEVEL OF EVIDENCE Level III, case control.
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Affiliation(s)
- Christopher J Burke
- Department of Radiology, NYU Hospital for Joint Diseases, New York, New York, U.S.A..
| | - Daniel Kaplan
- Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A
| | - Tobias Block
- NYU Center for Biomedical Imaging, New York, New York, U.S.A
| | - Gregory Chang
- NYU Center for Biomedical Imaging, New York, New York, U.S.A
| | - Laith Jazrawi
- Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A
| | - Kirk Campbell
- Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A
| | - Michael Alaia
- Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A
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Accelerated real-time cardiac MRI using iterative sparse SENSE reconstruction: comparing performance in patients with sinus rhythm and atrial fibrillation. Eur Radiol 2018; 28:3088-3096. [DOI: 10.1007/s00330-017-5283-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/12/2017] [Accepted: 12/22/2017] [Indexed: 12/19/2022]
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Investigation of the XCAT phantom as a validation tool in cardiac MRI tracking algorithms. Phys Med 2018; 45:44-51. [DOI: 10.1016/j.ejmp.2017.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 11/23/2017] [Accepted: 12/03/2017] [Indexed: 11/22/2022] Open
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Accelerated Computing in Magnetic Resonance Imaging: Real-Time Imaging Using Nonlinear Inverse Reconstruction. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:3527269. [PMID: 29463984 PMCID: PMC5804376 DOI: 10.1155/2017/3527269] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 11/07/2017] [Indexed: 12/04/2022]
Abstract
Purpose To develop generic optimization strategies for image reconstruction using graphical processing units (GPUs) in magnetic resonance imaging (MRI) and to exemplarily report on our experience with a highly accelerated implementation of the nonlinear inversion (NLINV) algorithm for dynamic MRI with high frame rates. Methods The NLINV algorithm is optimized and ported to run on a multi-GPU single-node server. The algorithm is mapped to multiple GPUs by decomposing the data domain along the channel dimension. Furthermore, the algorithm is decomposed along the temporal domain by relaxing a temporal regularization constraint, allowing the algorithm to work on multiple frames in parallel. Finally, an autotuning method is presented that is capable of combining different decomposition variants to achieve optimal algorithm performance in different imaging scenarios. Results The algorithm is successfully ported to a multi-GPU system and allows online image reconstruction with high frame rates. Real-time reconstruction with low latency and frame rates up to 30 frames per second is demonstrated. Conclusion Novel parallel decomposition methods are presented which are applicable to many iterative algorithms for dynamic MRI. Using these methods to parallelize the NLINV algorithm on multiple GPUs, it is possible to achieve online image reconstruction with high frame rates.
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4D real-time phase-contrast flow MRI with sparse sampling. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:3252-3255. [PMID: 29060591 DOI: 10.1109/embc.2017.8037550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Conventional phase-contrast (PC) MRI relies on electrocardiogram (ECG)-synchronized cine acquisition and respiration control. It often results in relatively low data acquisition efficiency, and is unable to assess blood flow variabilities. Real-time imaging is a promising technique to overcome these limitations; however, it results in a challenging image reconstruction problem with highly-undersampled (k; t)-space data. This paper presents a novel model-based imaging method, which integrates low-rank modeling with parallel imaging, to enable 4D real-time PC MRI without ECG gating and respiration control. The proposed method achieves an isotropic spatial resolution of 2.4 mm and temporal resolution of 35.2 ms, with three directional flow encodings. Moreover, it is able to resolve beat-by-beat flow variations, which cannot be achieved by the conventional cine-based approach. The proposed method was evaluated with in vivo experiments with one healthy subject and one arrhythmic patient. For the first time, we demonstrate the feasibility of 4D real-time PC MRI.
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Sohns JM, Menke J, Bergau L, Weiss BG, Schmuck S, Weiberg D, Staab W, Derlin T, Dorenkamp M, Sohns C. Extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities: A retrospective study of 352 patients. Vascular 2017; 26:27-38. [DOI: 10.1177/1708538117714401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background The aim of this study was to assess the prevalence and clinical significance of extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities. Materials and methods Three hundred fifty-two patients underwent abdominal, pelvic and lower extremity 1.5 T magnetic resonance angiography. Clinically relevant vascular and extra-vascular findings were identified. Relevant vascular findings were classified as stenosis, occlusion, aneurysm, sclerosis, dissection or vasculitis. Relevant extra-vascular findings were categorized as ‘safe’ (Group A), intermediate – requiring additional investigation – (Group B) and malignant/endangering – requiring change of therapy (Group C). Results A total of 2152 clinically relevant vascular findings was identified (6.1/patient). The most frequent vascular finding was femoral artery stenosis (10.6%). Four hundred fifty-one extra-vascular findings were observed (1.3/patient) and classified into Group A (78%), Group B (19.5%) and Group C findings (2.4%). The most frequent malignant findings were lung cancer, lymphoma, osteosarcoma, hepatocellular carcinoma and renal cell carcinoma (7/352 patients). Conclusions Extravascular findings are frequently encountered in magnetic resonance angiography performed for vascular indications. Clinically relevant findings are seen in a substantial part of patients and should prompt further diagnostic work-up.
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Affiliation(s)
- Jan M Sohns
- Department of Nuclear Medicine, Hannover Medical School, MHH, Hannover, Germany
- German Center for Cardiovascular Research, DZHK, Berlin, Germany
| | - Jan Menke
- Institute for Diagnostic and Interventional Radiology, Georg-August University, UMG, Göttingen, Germany
| | - Leonard Bergau
- German Center for Cardiovascular Research, DZHK, Berlin, Germany
- Department of Cardiology and Pneumology, Georg-August University, UMG, Göttingen, Germany
| | - Bernhard G Weiss
- Department of Otorhinolaryngology-Head and Neck Surgery, Georg-August University, UMG, Göttingen, Germany
| | - Sebastian Schmuck
- Department of Nuclear Medicine, Hannover Medical School, MHH, Hannover, Germany
| | - Desiree Weiberg
- Department of Nuclear Medicine, Hannover Medical School, MHH, Hannover, Germany
| | - Wieland Staab
- German Center for Cardiovascular Research, DZHK, Berlin, Germany
- Institute for Diagnostic and Interventional Radiology, Georg-August University, UMG, Göttingen, Germany
| | - Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, MHH, Hannover, Germany
| | - Marc Dorenkamp
- Department of Medicine, Cardiology Division, Charité Campus Virchow Klinikum, Berlin, Germany
| | - Christian Sohns
- Electrophysiology Bremen, Heart Center Bremen, Am Klinikum Links der Weser, Bremen, Germany
- Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany
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Sun A, Zhao B, Li Y, He Q, Li R, Yuan C. Real-time phase-contrast flow cardiovascular magnetic resonance with low-rank modeling and parallel imaging. J Cardiovasc Magn Reson 2017; 19:19. [PMID: 28183320 PMCID: PMC5301411 DOI: 10.1186/s12968-017-0330-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 01/19/2017] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Conventional phase-contrast cardiovascular magnetic resonance (PC-CMR) employs cine-based acquisitions to assess blood flow condition, in which electro-cardiogram (ECG) gating and respiration control are generally required. This often results in lower acquisition efficiency, and limited utility in the presence of cardiovascular pathology (e.g., cardiac arrhythmia). Real-time PC-CMR, without ECG gating and respiration control, is a promising alternative that could overcome limitations of the conventional approach. But real-time PC-CMR involves image reconstruction from highly undersampled (k, t)-space data, which is very challenging. In this study, we present a novel model-based imaging method to enable high-resolution real-time PC-CMR with sparse sampling. METHODS The proposed method captures spatiotemporal correlation among flow-compensated and flow-encoded image sequences with a novel low-rank model. The image reconstruction problem is then formulated as a low-rank matrix recovery problem. With proper temporal subspace modeling, it results in a convex optimization formulation. We further integrate this formulation with the SENSE-based parallel imaging model to handle multichannel acquisitions. The performance of the proposed method was systematically evaluated in 2D real-time PC-CMR with flow phantom experiments and in vivo experiments (with healthy subjects). Additionally, we performed a feasibility study of the proposed method on patients with cardiac arrhythmia. RESULTS The proposed method achieves a spatial resolution of 1.8 mm and a temporal resolution of 18 ms for 2D real-time PC-CMR with one directional flow encoding. For the flow phantom experiments, both regular and irregular flow patterns were accurately captured. For the in vivo experiments with healthy subjects, flow dynamics obtained from the proposed method correlated well with those from the cine-based acquisitions. For the experiments with the arrhythmic patients, the proposed method demonstrated excellent capability of resolving the beat-by-beat flow variations, which cannot be obtained from the conventional cine-based method. CONCLUSION The proposed method enables high-resolution real-time PC-CMR at 2D without ECG gating and respiration control. It accurately resolves beat-by-beat flow variations, which holds great promise for studying patients with irregular heartbeats.
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Affiliation(s)
- Aiqi Sun
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Haidian District, Beijing, China
| | - Bo Zhao
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Chalestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Yunduo Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Haidian District, Beijing, China
| | - Qiong He
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Haidian District, Beijing, China
| | - Rui Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Haidian District, Beijing, China.
| | - Chun Yuan
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Haidian District, Beijing, China
- Vascular Imaging Lab, Department of Radiology, University of Washington, Seattle, WA, USA
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Identification of the Upward Movement of Human CSF In Vivo and its Relation to the Brain Venous System. J Neurosci 2017; 37:2395-2402. [PMID: 28137972 DOI: 10.1523/jneurosci.2754-16.2017] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/13/2017] [Accepted: 01/18/2017] [Indexed: 01/01/2023] Open
Abstract
CSF flux is involved in the pathophysiology of neurodegenerative diseases and cognitive impairment after traumatic brain injury, all hallmarked by the accumulation of cellular metabolic waste. Its effective disposal via various CSF routes has been demonstrated in animal models. In contrast, the CSF dynamics in humans are still poorly understood. Using novel real-time MRI, forced inspiration has been identified recently as a main driving force of CSF flow in the human brain. Exploiting technical advances toward real-time phase-contrast MRI, the current work analyzed directions, velocities, and volumes of human CSF flow within the brain aqueduct as part of the internal ventricular system and in the spinal canal during respiratory cycles. A consistent upward CSF movement toward the brain in response to forced inspiration was seen in all subjects at the aqueduct, in 11/12 subjects at thoracic level 2, and in 4/12 subjects at thoracic level 5. Concomitant analyses of CSF dynamics and cerebral venous blood flow, that is, in epidural veins at cervical level 3, uniquely demonstrated CSF and venous flow to be closely communicating cerebral fluid systems in which inspiration-induced downward flow of venous blood due to reduced intrathoracic pressure is counterbalanced by an upward movement of CSF. The results extend our understanding of human CSF flux and open important clinical implications, including concepts for drug delivery and new classifications and therapeutic options for various forms of hydrocephalus and idiopathic intracranial hypertension.SIGNIFICANCE STATEMENT Effective disposal of brain cellular waste products via CSF has been demonstrated repeatedly in animal models. However, CSF dynamics in humans are still poorly understood. A novel quantitative real-time MRI technique yielded in vivo CSF flow directions, velocities, and volumes in the human brain and upper spinal canal. CSF moved upward toward the head in response to forced inspiration. Concomitant analysis of brain venous blood flow indicated that CSF and venous flux act as closely communicating systems. The finding of a human CSF-venous network with upward CSF net movement opens new clinical concepts for drug delivery and new classifications and therapeutic options for various forms of hydrocephalus and ideopathic intracranial hypertension.
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Joseph AA, Merboldt KD, Voit D, Dahm J, Frahm J. Real-time magnetic resonance imaging of deep venous flow during muscular exercise-preliminary experience. Cardiovasc Diagn Ther 2016; 6:473-481. [PMID: 28123969 DOI: 10.21037/cdt.2016.11.02] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The accurate assessment of peripheral venous flow is important for the early diagnosis and treatment of disorders such as deep-vein thrombosis (DVT) which is a major cause of post-thrombotic syndrome or even death due to pulmonary embolism. The aim of this work is to quantitatively determine blood flow in deep veins during rest and muscular exercise using a novel real-time magnetic resonance imaging (MRI) method for velocity-encoded phase-contrast (PC) MRI at high spatiotemporal resolution. METHODS Real-time PC MRI of eight healthy volunteers and one patient was performed at 3 Tesla (Prisma fit, Siemens, Erlangen, Germany) using a flexible 16-channel receive coil (Variety, NORAS, Hoechberg, Germany). Acquisitions were based on a highly undersampled radial FLASH sequence with image reconstruction by regularized nonlinear inversion at 0.5×0.5×6 mm3 spatial resolution and 100 ms temporal resolution. Flow was assessed in two cross-sections of the lower leg at the level of the calf muscle and knee using a protocol of 10 s rest, 20 s flexion and extension of the foot, and 10 s rest. Quantitative analyses included through-plane flow in the right posterior tibial, right peroneal and popliteal vein (PC maps) as well as signal intensity changes due to flow and muscle movements (corresponding magnitude images). RESULTS Real-time PC MRI successfully monitored the dynamics of venous flow at high spatiotemporal resolution and clearly demonstrated increased flow in deep veins in response to flexion and extension of the foot. In normal subjects, the maximum velocity (averaged across vessel lumen) during exercise was 9.4±5.7 cm·s-1 for the right peroneal vein, 8.5±4.6 cm·s-1 for the right posterior tibial vein and 17.8±5.8 cm·s-1 for the popliteal vein. The integrated flow volume per exercise (20 s) was 1.9, 1.6 and 50 mL (mean across subjects) for right peroneal, right posterior tibial and popliteal vein, respectively. A patient with DVT presented with peak flow velocities of only about 2 cm·s-1 during exercise and less than 1 cm·s-1 during rest. CONCLUSIONS Real-time PC MRI emerges as a new tool for quantifying the dynamics of muscle-induced flow in deep veins. The method provides both signal intensity changes and velocity information for the assessment of blood flow and muscle movements. It now warrants extended clinical trials to patients with suspected thrombosis.
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Affiliation(s)
- Arun Antony Joseph
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany;; DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
| | - Klaus-Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Johannes Dahm
- Herz & Gefäßzentrum Göttingen am Krankenhaus Neu-Bethlehem, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany;; DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
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Technical Considerations for the Generation of Adoptively Transferred T Cells in Cancer Immunotherapy. Cancers (Basel) 2016; 8:cancers8090086. [PMID: 27657129 PMCID: PMC5040988 DOI: 10.3390/cancers8090086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/04/2016] [Accepted: 09/12/2016] [Indexed: 12/28/2022] Open
Abstract
A significant function of the immune system is the surveillance and elimination of aberrant cells that give rise to cancer. Even when tumors are well established and metastatic, immune-mediated spontaneous regressions have been documented. While there are have been various forms of immunotherapy, one of the most widely studied for almost 40 years is adoptive cellular immunotherapy, but its success has yet to be fully realized. Adoptive cell transfer (ACT) is a therapeutic modality that has intrigued physicians and researchers for its many theoretical benefits. Preclinical investigations and human trials have utilized natural killer (NK) cells, dendritic cells (DC), macrophages, T-cells or B-cells for ACT with the most intense research focused on T-cell ACT. T-cells are exquisitely specific to the target of its T-cell receptor (TCR), thus potentially reducing the amount of collateral damage and off-target effects from treatment. T-cells also possess a memory subset that may reduce the risk of recurrence of a cancer after the successful treatment of the primary disease. There are several options for the source of T-cells used in the generation of cells for ACT. Perhaps the most widely known source is T-cells generated from tumor-infiltrating lymphocytes (TILs). However, studies have also employed peripheral blood mononuclear cells (PBMCs), lymph nodes, and even induced pluripotent stem cells (IPSCs) as a source of T-cells. Several important technical considerations exist regarding benefits and limitations of each source of T-cells. Unique aspects of T-cells factor into their ability to be efficacious in ACT including the total number of cells available for ACT, the anti-tumor efficacy on a per cell basis, the repertoire of TCRs specific to tumor cells, and their ability to traffic to various organs that harbor tumor. Current research is attempting to unlock the full potential of these cells to effectively and safely treat cancer.
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Tan Z, Roeloffs V, Voit D, Joseph AA, Untenberger M, Merboldt KD, Frahm J. Model-based reconstruction for real-time phase-contrast flow MRI: Improved spatiotemporal accuracy. Magn Reson Med 2016; 77:1082-1093. [PMID: 26949221 DOI: 10.1002/mrm.26192] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/09/2016] [Accepted: 02/09/2016] [Indexed: 12/27/2022]
Abstract
PURPOSE To develop a model-based reconstruction technique for real-time phase-contrast flow MRI with improved spatiotemporal accuracy in comparison to methods using phase differences of two separately reconstructed images with differential flow encodings. METHODS The proposed method jointly computes a common image, a phase-contrast map, and a set of coil sensitivities from every pair of flow-compensated and flow-encoded datasets obtained by highly undersampled radial FLASH. Real-time acquisitions with five and seven radial spokes per image resulted in 25.6 and 35.7 ms measuring time per phase-contrast map, respectively. The signal model for phase-contrast flow MRI requires the solution of a nonlinear inverse problem, which is accomplished by an iteratively regularized Gauss-Newton method. Aspects of regularization and scaling are discussed. The model-based reconstruction was validated for a numerical and experimental flow phantom and applied to real-time phase-contrast MRI of the human aorta for 10 healthy subjects and 2 patients. RESULTS Under all conditions, and compared with a previously developed real-time flow MRI method, the proposed method yields quantitatively accurate phase-contrast maps (i.e., flow velocities) with improved spatial acuity, reduced phase noise and reduced streaking artifacts. CONCLUSION This novel model-based reconstruction technique may become a new tool for clinical flow MRI in real time. Magn Reson Med 77:1082-1093, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zhengguo Tan
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Volkert Roeloffs
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
| | - Markus Untenberger
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - K Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
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Advanced flow MRI: emerging techniques and applications. Clin Radiol 2016; 71:779-95. [PMID: 26944696 DOI: 10.1016/j.crad.2016.01.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/10/2015] [Accepted: 01/10/2016] [Indexed: 12/12/2022]
Abstract
Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented.
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Sohns JM, Kowallick JT, Joseph AA, Merboldt KD, Voit D, Fasshauer M, Staab W, Frahm J, Lotz J, Unterberg-Buchwald C. Peak flow velocities in the ascending aorta-real-time phase-contrast magnetic resonance imaging vs. cine magnetic resonance imaging and echocardiography. Quant Imaging Med Surg 2015; 5:685-90. [PMID: 26682138 DOI: 10.3978/j.issn.2223-4292.2015.08.08] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
This prospective study of eight healthy volunteers evaluates peak flow velocities (PFV) in the ascending aorta using real-time phase-contrast magnetic resonance imaging (MRI) in comparison to cine phase-contrast MRI and echocardiography. Flow measurements by echocardiography and cine phase-contrast MRI with breath-holding were performed according to clinical standards. Real-time phase-contrast MRI at 40 ms temporal resolution and 1.3 mm in-plane resolution was based on highly undersampled radial fast low-angle shot (FLASH) sequences with image reconstruction by regularized nonlinear inversion (NLINV). Evaluations focused on the determination of PFV. Linear regressions and Bland-Altman plots were used for comparisons of methods. When averaged across subjects, real-time phase-contrast MRI resulted in PFV of 120±20 cm s(-1) (mean ± SD) in comparison to 122±16 cm s(-1) for cine MRI and 124±20 cm s(-1) for echocardiography. The maximum deviations between real-time phase-contrast MRI and echocardiography ranged from -20 to +14 cm s(-1) (cine MRI: -10 to +12 cm s(-1)). Thus, in general, real-time phase-contrast MRI of cardiac outflow revealed quantitative agreement with cine MRI and echocardiography. The advantages of real-time MRI are measurements during free breathing and access to individual cardiac cycles.
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Affiliation(s)
- Jan M Sohns
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Johannes T Kowallick
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Arun A Joseph
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - K Dietmar Merboldt
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Voit
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Martin Fasshauer
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Wieland Staab
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Jens Frahm
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Joachim Lotz
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
| | - Christina Unterberg-Buchwald
- 1 Institute for Diagnostic and Interventional Radiology, Heart Center, University Medical Center Göttingen, Göttingen, Germany ; 2 German Centre for Cardiovascular Research, DZHK, partnersite Göttingen, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany ; 4 Department of Cardiology and Pneumology, Heart Center, University Medical Center Göttingen, Göttingen, Germany
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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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Iltis PW, Schoonderwaldt E, Zhang S, Frahm J, Altenmüller E. Real-time MRI comparisons of brass players: A methodological pilot study. Hum Mov Sci 2015; 42:132-45. [DOI: 10.1016/j.humov.2015.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 10/23/2022]
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Real-time phase contrast magnetic resonance imaging for assessment of haemodynamics: from phantom to patients. Eur Radiol 2015; 26:986-96. [PMID: 26188655 DOI: 10.1007/s00330-015-3897-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/03/2015] [Accepted: 06/22/2015] [Indexed: 01/02/2023]
Abstract
OBJECTIVES Assessment of haemodynamics is crucial in many cardiac diseases. Phase contrast MRI (PC-MRI) can accurately access it. Arrhythmia is a major limitation in conventional segmented PC-MRI (SEG). A real-time PC-MRI sequence (RT) could overcome this. We validated RT by comparing to SEG. METHODS A prototype RT using shared velocity encoding was tested against SEG at 1.5 T in a flow phantom and consecutively included patients with (n = 55) or without (n = 59) aortic valve disease. In patients with atrial fibrillation (Afib, n = 15), only RT was applied. Phantom: PC images were acquired in front of and behind an interchangeable aortic-stenosis-like inlay. Mean velocity and flow were quantified. PATIENTS PC images were acquired in the ascending aorta, pulmonary trunk and superior caval vein. Peak velocity, stroke volume and regurgitant fraction were quantified. RESULTS Phantom: Mean velocities (11 ± 1 to 207 ± 10 cm/s) and flow correlated closely between SEG and RT (r ≥ 0.99, ICC ≥ 0.98, p < 0.0005). Patients without AVD or with aortic regurgitation: Concordance of SEG and RT was excellent regarding peak velocities, stroke volumes (r ≥ 0.91, ICC ≥ 0.94, p < 0.0005) and regurgitant fractions (r = 0.95, ICC = 0.95, p < 0.0005). RT was feasible in all patients with Afib. CONCLUSIONS The real-time sequence is accurate compared to conventional segmented PC-MRI. Its applicability in Afib was shown. Real-time PC-MRI might become a valuable tool in arrhythmia. KEY POINTS • Assessment of haemodynamics is crucial in many cardiac diseases. • Arrhythmias are a major limitation of conventional techniques in cardiac magnetic resonance. • A real-time technique, which allows application in arrhythmia, was validated. • This real-time technique might become a valuable tool in arrhythmic patients.
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Zhang S, Joseph AA, Gross L, Ghadimi M, Frahm J, Beham AW. Diagnosis of Gastroesophageal Reflux Disease Using Real-time Magnetic Resonance Imaging. Sci Rep 2015; 5:12112. [PMID: 26175205 PMCID: PMC4648433 DOI: 10.1038/srep12112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 04/30/2015] [Indexed: 12/31/2022] Open
Abstract
A small angle (His angle) between the oesophagus and the fundus of the stomach is considered to act as flap valve and anti-reflux barrier. A wide angle results in dysfunction of the oesophagogastric junction and subsequently in gastroesophageal reflux disease (GERD). Here, we used real-time magnetic resonance imaging (MRI) at 50 ms resolution (20 frames per second) in 12 volunteers and 12 patients with GERD to assess transport of pineapple juice through the oesophagogastric junction and reflux during Valsalva. We found that the intra-abdominal part of the oesophagus was bended towards the left side resulting in an angle of 75.3 ± 17.4, which was significantly larger during Valsava (P = 0.017). Reflux and several underlying pathologies were detected in 11 out of 12 patients. Our data visualize oesophagogastric junction physiology and disprove the flap valve hypothesis. Further, non-invasive real-time MRI has considerable potential for the diagnosis of causative pathologies leading to GERD.
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Affiliation(s)
- Shuo Zhang
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Lisa Gross
- Department of Surgery, University Medical Center, Göttingen, Germany
| | - Michael Ghadimi
- Department of Surgery, University Medical Center, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Alexander W Beham
- Department of Surgery, University Medical Center, Göttingen, Germany
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Untenberger M, Tan Z, Voit D, Joseph AA, Roeloffs V, Merboldt KD, Schätz S, Frahm J. Advances in real-time phase-contrast flow MRI using asymmetric radial gradient echoes. Magn Reson Med 2015; 75:1901-8. [PMID: 26096085 DOI: 10.1002/mrm.25696] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/17/2015] [Accepted: 02/24/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE To provide multidimensional velocity compensation for real-time phase-contrast flow MRI. METHODS The proposed method introduces asymmetric gradient echoes for highly undersampled radial FLASH MRI with phase-sensitive image reconstruction by regularized nonlinear inversion (NLINV). Using an adapted gradient delay correction the resulting image quality was analyzed by simulations and experimentally validated at 3 Tesla. For real-time flow MRI the reduced gradient-echo timing allowed for the incorporation of velocity-compensating waveforms for all imaging gradients at even shorter repetition times. RESULTS The results reveal a usable degree of 20% asymmetry. Real-time flow MRI with full velocity compensation eliminated signal void in a flow phantom, confirmed flow parameters in healthy subjects and demonstrated signal recovery and phase conservation in a patient with aortic valve insufficiency and stenosis. Exemplary protocols at 1.4-1.5 mm resolution and 6 mm slice thickness achieved total acquisition times of 33.3-35.7 ms for two images (7 spokes each) with and without flow-encoding gradient. CONCLUSION Asymmetric gradient echoes were successfully implemented for highly undersampled radial trajectories. The resulting temporal gain offers full velocity compensation for real-time phase-contrast flow MRI which minimizes false-positive contributions from complex flow and further enhances the temporal resolution compared with acquisitions with symmetric echoes.
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Affiliation(s)
- Markus Untenberger
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Zhengguo Tan
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
| | - Volkert Roeloffs
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - K Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Sebastian Schätz
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
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Iltis PW, Frahm J, Voit D, Joseph AA, Schoonderwaldt E, Altenmüller E. High-speed real-time magnetic resonance imaging of fast tongue movements in elite horn players. Quant Imaging Med Surg 2015; 5:374-81. [PMID: 26029640 DOI: 10.3978/j.issn.2223-4292.2015.03.02] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 02/27/2015] [Indexed: 12/23/2022]
Abstract
This paper describes the use of high-speed real-time (RT) magnetic resonance imaging (MRI) in quantifying very rapid motor function within the oropharyngeal cavity of six elite horn players. Based on simultaneous sound recordings, the efficacy of RT-MRI films at 30 and 100 frames per second (fps) was assessed for tongue movements associated with double tonguing performance. Serial images with a nominal temporal resolution of 10.0 and 33.3 ms were obtained by highly undersampled radial fast low-angle shot (FLASH) sequences (5 and 17 spokes, respectively) using complementary sets of spokes for successive acquisitions (extending over 9 and 5 frames, respectively). Reconstructions of high-speed images were obtained by temporally regularized nonlinear inversion (NLINV) as previously described. A customized MATLAB toolkit was developed for the extraction of line profiles from MRI films to quantify temporal phenomena associated with task performance. The analyses reveal that for the present setting, which required the use of a temporal median filter to optimize image quality, acquisition rates of 30 fps are inadequate to accurately detect tongue movements during double tonguing, but that rates of 100 fps do allow for a precise quantification of movement. These data for the first time demonstrate the extreme performance of elite horn players. High-speed RT-MRI offers so far unavailable opportunities to study the oropharyngeal movements during brass playing with future potential for teaching and the treatment of patients suffering from dystonia.
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Affiliation(s)
- Peter W Iltis
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Erwin Schoonderwaldt
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Eckart Altenmüller
- 1 Department of Kinesiology, Gordon College, Wenham, MA, USA ; 2 University of Music, Drama and Media, Hannover, Germany ; 3 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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Abstract
The mechanisms behind CSF flow in humans are still not fully known. CSF circulates from its primary production sites at the choroid plexus through the brain ventricles to reach the outer surface of the brain in the subarachnoid spaces from where it drains into venous bloodstream and cervical lymphatics. According to a recent concept of brain fluid transport, established in rodents, CSF from the brain surface also enters the brain tissue along para-arterial routes and exits through paravenous spaces again into subarachnoid compartments. This unidirectional flow is mainly driven by arterial pulsation. To investigate how CSF flow is regulated in humans, we applied a novel real-time magnetic resonance imaging technique at high spatial (0.75 mm) and temporal (50 ms) resolution in healthy human subjects. We observed significant CSF flow exclusively with inspiration. In particular, during forced breathing, high CSF flow was elicited during every inspiration, whereas breath holding suppressed it. Only a minor flow component could be ascribed to cardiac pulsation. The present results unambiguously identify inspiration as the most important driving force for CSF flow in humans. Inspiratory thoracic pressure reduction is expected to directly modulate the hydrostatic pressure conditions for the low-resistance paravenous, venous, and lymphatic clearance routes of CSF. Furthermore, the experimental approach opens new clinical opportunities to study the pathophysiology of various forms of hydrocephalus and to design therapeutic strategies in relation to CSF flow alterations.
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Hutter J, Schmitt P, Saake M, Stubinger A, Grimm R, Forman C, Greiser A, Hornegger J, Maier A. Multi-dimensional flow-preserving compressed sensing (MuFloCoS) for time-resolved velocity-encoded phase contrast MRI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:400-414. [PMID: 25252278 DOI: 10.1109/tmi.2014.2359238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
4-D time-resolved velocity-encoded phase-contrast MRI (4-D PCI) is a fully non-invasive technique to assess hemodynamics in vivo with a broad range of potential applications in multiple cardiovascular diseases. It is capable of providing quantitative flow values and anatomical information simultaneously. The long acquisition time, however, still inhibits its wider clinical use. Acceleration is achieved at present using parallel MRI (pMRI) techniques which can lead to substantial loss of image quality for higher acceleration factors. Both the high-dimensionality and the significant degree of spatio-temporal correlation in 4-D PCI render it ideally suited for recently proposed compressed sensing (CS) techniques. We propose the Multi-Dimensional Flow-preserving Compressed Sensing (MuFloCoS) method to exploit these properties. A multi-dimensional iterative reconstruction is combined with an interleaved sampling pattern (I-VT), an adaptive masked and weighted temporal regularization (TMW) and fully automatically obtained vessel-masks. The performance of the novel method was analyzed concerning image quality, feasibility of acceleration factors up to 15, quantitative flow values and diagnostic accuracy in phantom experiments and an in vivo carotid study with 18 volunteers. Comparison with iterative state-of-the-art methods revealed significant improvements using the new method, the temporal normalized root mean square error of the peak velocity was reduced by 45.32% for the novel MuFloCoS method with acceleration factor 9. The method was furthermore applied to two patient cases with diagnosed high-grade stenosis of the ICA, which confirmed the performance of MuFloCoS to produce valuable results in the presence of pathological findings in 56 s instead of over 8 min (full sampling).
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Abstract
4D flow MRI permits a comprehensive in-vivo assessment of three-directional blood flow within 3-dimensional vascular structures throughout the cardiac cycle. Given the large coverage permitted from a 4D flow acquisition, the distribution of vessel wall and flow parameters along an entire vessel of interest can thus be derived from a single measurement without being dependent on multiple predefined 2D acquisitions. In addition to qualitative 3D visualizations of complex cardiac and vascular flow patterns, quantitative flow analysis can be performed and is complemented by the ability to compute sophisticated hemodynamic parameters, such as wall shear stress or 3D pressure difference maps. These metrics can provide information previously unavailable with conventional modalities regarding the impact of cardiovascular disease or therapy on global and regional changes in hemodynamics. This review provides an introduction to the methodological aspects of 4D flow MRI to assess vascular hemodynamics and describes its potential for the assessment and understanding of altered hemodynamics in the presence of cardiovascular disease.
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50
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Zhang S, Joseph AA, Voit D, Schaetz S, Merboldt KD, Unterberg-Buchwald C, Hennemuth A, Lotz J, Frahm J. Real-time magnetic resonance imaging of cardiac function and flow-recent progress. Quant Imaging Med Surg 2014; 4:313-29. [PMID: 25392819 DOI: 10.3978/j.issn.2223-4292.2014.06.03] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 05/30/2014] [Indexed: 11/14/2022]
Abstract
Cardiac structure, function and flow are most commonly studied by ultrasound, X-ray and magnetic resonance imaging (MRI) techniques. However, cardiovascular MRI is hitherto limited to electrocardiogram (ECG)-synchronized acquisitions and therefore often results in compromised quality for patients with arrhythmias or inabilities to comply with requested protocols-especially with breath-holding. Recent advances in the development of novel real-time MRI techniques now offer dynamic imaging of the heart and major vessels with high spatial and temporal resolution, so that examinations may be performed without the need for ECG synchronization and during free breathing. This article provides an overview of technical achievements, physiological validations, preliminary patient studies and translational aspects for a future clinical scenario of cardiovascular MRI in real time.
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Affiliation(s)
- Shuo Zhang
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Arun A Joseph
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Dirk Voit
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Sebastian Schaetz
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Klaus-Dietmar Merboldt
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Christina Unterberg-Buchwald
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Anja Hennemuth
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Joachim Lotz
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
| | - Jens Frahm
- 1 Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen 37070, Germany ; 2 DZHK (German Cardiovascular Research Center), partner site Göttingen, Göttingen, Germany ; 3 Diagnostische und Interventionelle Radiologie, 4 Kardiologie und Pneumologie, Universitätsmedizin Göttingen, Göttingen 37075, Germany ; 5 Fraunhofer MEVIS Institute for Medical Image Computing, Bremen, Germany
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