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Lin K, Sarnari R, Speier P, Hayes C, Davids R, Carr JC, Markl M. Pilot Tone-Triggered MRI for Quantitative Assessment of Cardiac Function, Motion, and Structure. Invest Radiol 2023; 58:239-243. [PMID: 36070525 PMCID: PMC10016086 DOI: 10.1097/rli.0000000000000922] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that there are good agreements between cardiac functional and structural indices derived from magnetic resonance imaging (MRI) sequences triggered with pilot tone (PT) and electrocardiogram (ECG). MATERIALS AND METHODS Sixteen healthy volunteers (11 male, age 21-76 years) underwent a cardiac MRI scan. Cine MRI, T1, and T2 mapping were acquired by using PT and ECG triggering. Quantitative measurements, including left and right ventricular end-diastolic volume, end-systolic volume, stroke volume, ejection fraction, longitudinal strain, left ventricular T1 and T2 values, left and right atrial longitudinal strain, and maximal/minimal volumes, were measured. The interclass correlation coefficient, coefficient of variation, and Bland-Altman plots were used to evaluate the agreements between measurements derived by MRI sequences triggered with 2 methods. RESULTS There were no significant differences among end-diastolic volume, end-systolic volume, stroke volume, ejection fraction, left ventricle mass, T1 and T2 values, or longitudinal strains acquired using PT and ECG. There were good agreements and low variations between the levels of these indices acquired with PT and ECG. Interclass correlation coefficients mainly ranged from 0.73 to 0.98. The coefficients of variation ranged from 1.4% to 22.6%. CONCLUSIONS Pilot tone-triggered MRI provides comparable measurements of cardiac function, motion, and structure as ECG-triggered MRI. Pilot tone has the potential to become a backup of ECG gating in cardiovascular imaging.
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Affiliation(s)
- Kai Lin
- Department of Radiology, Northwestern University, Chicago, IL
| | - Roberto Sarnari
- Department of Radiology, Northwestern University, Chicago, IL
| | | | | | | | - James C. Carr
- Department of Radiology, Northwestern University, Chicago, IL
| | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, IL
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Cao T, Wang N, Kwan AC, Lee HL, Mao X, Xie Y, Nguyen KL, Colbert CM, Han F, Han P, Han H, Christodoulou AG, Li D. Free-breathing, non-ECG, simultaneous myocardial T 1 , T 2 , T 2 *, and fat-fraction mapping with motion-resolved cardiovascular MR multitasking. Magn Reson Med 2022; 88:1748-1763. [PMID: 35713184 PMCID: PMC9339519 DOI: 10.1002/mrm.29351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/18/2022] [Accepted: 05/17/2022] [Indexed: 01/11/2023]
Abstract
PURPOSE To develop a free-breathing, non-electrocardiogram technique for simultaneous myocardial T1 , T2 , T2 *, and fat-fraction (FF) mapping in a single scan. METHODS The MR Multitasking framework is adapted to quantify T1 , T2 , T2 *, and FF simultaneously. A variable TR scheme is developed to preserve temporal resolution and imaging efficiency. The underlying high-dimensional image is modeled as a low-rank tensor, which allows accelerated acquisition and efficient reconstruction. The accuracy and/or repeatability of the technique were evaluated on static and motion phantoms, 12 healthy volunteers, and 3 patients by comparing to the reference techniques. RESULTS In static and motion phantoms, T1 /T2 /T2 */FF measurements showed substantial consistency (R > 0.98) and excellent agreement (intraclass correlation coefficient > 0.93) with reference measurements. In human subjects, the proposed technique yielded repeatable T1 , T2 , T2 *, and FF measurements that agreed with those from references. CONCLUSIONS The proposed free-breathing, non-electrocardiogram, motion-resolved Multitasking technique allows simultaneous quantification of myocardial T1 , T2 , T2 *, and FF in a single 2.5-min scan.
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Affiliation(s)
- Tianle Cao
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
| | - Nan Wang
- Radiology Department, Stanford University, Stanford, California, USA
| | - Alan C. Kwan
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Imaging and Cardiology, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Hsu-Lei Lee
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Xianglun Mao
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Yibin Xie
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Kim-Lien Nguyen
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
- David Geffen School of Medicine and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Caroline M. Colbert
- David Geffen School of Medicine and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
- Physics and Biology in Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Fei Han
- Siemens Medical Solutions USA, Inc., Los Angeles, California, USA
| | - Pei Han
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
| | - Hui Han
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
| | - Anthony G. Christodoulou
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
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Qutbi M, Soltanshahi M, FarokhiMoghadam F, Ramandi FL, Kaghazchi F, Ahmadi R. Polarity status of trigger signal during ECG-gating affects parameters of LV function in gated myocardial perfusion SPECT. J Nucl Cardiol 2022; 29:2199-2209. [PMID: 34036529 DOI: 10.1007/s12350-021-02675-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION AND BACKGROUND The polarity status is one of the important items of specifications of trigger signal from cardiac trigger monitors with two options, either positive or negative. Some systems allow the user to set the polarity of trigger signal before imaging. Efforts should be made to set the polarity status according to the recommendations provided by the manufacturers. In case of inappropriate selection, changes in computation of end-systolic and end-diastolic volumes as well as ejection fraction may occur. OBJECTIVE To investigate the effect of the polarity status of trigger signals in synchronization process during 8- and 16-frame gated SPECT imaging on the systolic and diastolic parameters of LV function. METHODS Thirty-four patients referred for a myocardial perfusion SPECT were consecutively included in the study. The rest scan for each patient was performed with 8- and 16-frame gating simultaneously with positive trigger signal set by the operator in a cardiac trigger monitor and then repeated after manual selection of negative polarity. In total, the 4 imaging modes acquired were 8-frame/positive-trigger, 16-frame/positive-trigger, 8-frame/negative-trigger, and 16-frame/negative-trigger. All SPECT images were reconstructed and processed with the same values of parameters. Systolic and diastolic indices of LV function were derived in QGS of the Cedars-Sinai software and then were compared using various statistical tests, and a reliability analysis was also performed. RESULTS The age of patients recruited in the study was 58.41 ± 8.94, and 16 (47.1%) males and 18 (52.9%) females. All the correlation coefficients between corresponding parameters in positive and negative trigger signals were statistically significant. The difference between the parameters of systolic function including EF, EDV, and ESV in positive and negative trigger signals was statistically significant in paired sample t test. Likewise, a statistically significant difference was also found between mean phase angle in scans with positive and negative trigger signals by a phase difference of 147.91 (41.0% of an average cardiac cycle) and 149 (41.3% of an average cardiac cycle) degrees in 8- and 16-frame gating modes, respectively. Strong agreement (according to high values of intra-class correlation coefficient) was found for all four pairs. According to Bland-Altman results, an offset of about 3 percentage units was found, both between imaging in 8-frame gating compared to 16-frame gating, higher value in favor of 16-frame gating, and also between imaging with positive polarity trigger compared to negative-polarity trigger, again higher value in favor of positive-polarity triggering. CONCLUSION The status of the polarity of trigger signals or similar CTM-camera delays in synchronization process during 8- and 16-frame gated SPECT imaging can be considered as one of the factors that may influence systolic and diastolic indices of LV function.
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Affiliation(s)
- Mohsen Qutbi
- Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mehdi Soltanshahi
- Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farideh FarokhiMoghadam
- Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fahime Lamei Ramandi
- Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Kaghazchi
- Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Radiology, University of Pennsylvania Philadelphia, Philadelphia, USA
| | - Reyhane Ahmadi
- Department of Nuclear Medicine and Molecular Imaging, Farshchian Heart Center, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
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Hamilton-Craig C, Stäeb D, Al Najjar A, O’Brien K, Crawford W, Fletcher S, Barth M, Galloway G. 7-Tesla Functional Cardiovascular MR Using Vectorcardiographic Triggering-Overcoming the Magnetohydrodynamic Effect. ACTA ACUST UNITED AC 2021; 7:323-332. [PMID: 34449723 PMCID: PMC8396263 DOI: 10.3390/tomography7030029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/14/2021] [Accepted: 06/19/2021] [Indexed: 11/16/2022]
Abstract
Objective: Ultra-high-field B0 ≥ 7 tesla (7T) cardiovascular magnetic resonance (CMR) offers increased resolution. However, electrocardiogram (ECG) gating is impacted by the magneto-hydrodynamic effect distorting the ECG trace. We explored the technical feasibility of a 7T magnetic resonance scanner using an ECG trigger learning algorithm to quantitatively assess cardiac volumes and vascular flow. Methods: 7T scans were performed on 10 healthy volunteers on a whole-body research MRI MR scanner (Siemens Healthineers, Erlangen, Germany) with 8 channel Tx/32 channels Rx cardiac coils (MRI Tools GmbH, Berlin, Germany). Vectorcardiogram ECG was performed using a learning phase outside of the magnetic field, with a trigger algorithm overcoming severe ECG signal distortions. Vectorcardiograms were quantitatively analyzed for false negative and false positive events. Cine CMR was performed after 3rd-order B0 shimming using a high-resolution breath-held ECG-retro-gated segmented spoiled gradient echo, and 2D phase contrast flow imaging. Artefacts were assessed using a semi-quantitative scale. Results: 7T CMR scans were acquired in all patients (100%) using the vectorcardiogram learning method. 3,142 R-waves were quantitatively analyzed, yielding sensitivity of 97.6% and specificity of 98.7%. Mean image quality score was 0.9, sufficient to quantitate both cardiac volumes, ejection fraction, and aortic and pulmonary blood flow. Mean left ventricular ejection fraction was 56.4%, right ventricular ejection fraction was 51.4%. Conclusion: Reliable cardiac ECG triggering is feasible in healthy volunteers at 7T utilizing a state-of-the-art three-lead trigger device despite signal distortion from the magnetohydrodynamic effect. This provides sufficient image quality for quantitative analysis. Other ultra-high-field imaging applications such as human brain functional MRI with physiologic noise correction may benefit from this method of ECG triggering.
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Affiliation(s)
- Christian Hamilton-Craig
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Correspondence:
| | - Daniel Stäeb
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- MR Research Collaborations, Siemens Healthineers Pty Ltd., Bayswater, VIC 3153, Australia;
| | - Aiman Al Najjar
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Kieran O’Brien
- MR Research Collaborations, Siemens Healthineers Pty Ltd., Bayswater, VIC 3153, Australia;
| | - William Crawford
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Department of Medical Science, University of Oxford, Oxford 01865, UK
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4000, Australia
| | - Sabine Fletcher
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Markus Barth
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Graham Galloway
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Imaging Technology, Translational Research Institute, Brisbane, QLD 4000, Australia
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Reiter T, Lohr D, Hock M, Ankenbrand MJ, Stefanescu MR, Kosmala A, Kaspar M, Juchem C, Terekhov M, Schreiber LM. On the way to routine cardiac MRI at 7 Tesla - a pilot study on consecutive 84 examinations. PLoS One 2021; 16:e0252797. [PMID: 34297720 PMCID: PMC8301632 DOI: 10.1371/journal.pone.0252797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/23/2021] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION Cardiac magnetic resonance (CMR) at ultrahigh field (UHF) offers the potential of high resolution and fast image acquisition. Both technical and physiological challenges associated with CMR at 7T require specific hardware and pulse sequences. This study aimed to assess the current status and existing, publicly available technology regarding the potential of a clinical application of 7T CMR. METHODS Using a 7T MRI scanner and a commercially available radiofrequency coil, a total of 84 CMR examinations on 72 healthy volunteers (32 males, age 19-70 years, weight 50-103 kg) were obtained. Both electrocardiographic and acoustic triggering were employed. The data were analyzed regarding the diagnostic image quality and the influence of patient and hardware dependent factors. 50 complete short axis stacks and 35 four chamber CINE views were used for left ventricular (LV) and right ventricular (RV), mono-planar LV function, and RV fractional area change (FAC). Twenty-seven data sets included aortic flow measurements that were used to calculate stroke volumes. Subjective acceptance was obtained from all volunteers with a standardized questionnaire. RESULTS Functional analysis showed good functions of LV (mean EF 56%), RV (mean EF 59%) and RV FAC (mean FAC 52%). Flow measurements showed congruent results with both ECG and ACT triggering. No significant influence of experimental parameters on the image quality of the LV was detected. Small fractions of 5.4% of LV and 2.5% of RV segments showed a non-diagnostic image quality. The nominal flip angle significantly influenced the RV image quality. CONCLUSION The results demonstrate that already now a commercially available 7T MRI system, without major methods developments, allows for a solid morphological and functional analysis similar to the clinically established CMR routine approach. This opens the door towards combing routine CMR in patients with development of advanced 7T technology.
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Affiliation(s)
- Theresa Reiter
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
- Department of Internal Medicine I, Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - David Lohr
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
| | - Michael Hock
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
| | - Markus Johannes Ankenbrand
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
| | - Maria Roxana Stefanescu
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
| | - Aleksander Kosmala
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
- Department of Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Mathias Kaspar
- Department of Health Services Research, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Christoph Juchem
- Departments of Biomedical Engineering and Radiology, Columbia University, New York, New York, United States of America
| | - Maxim Terekhov
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
| | - Laura Maria Schreiber
- Comprehensive Heart Failure Center Wuerzburg (CHFC), Chair of Molecular and Cellular Imaging, Wuerzburg, Germany
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Ladrova M, Martinek R, Nedoma J, Hanzlikova P, Nelson MD, Kahankova R, Brablik J, Kolarik J. Monitoring and Synchronization of Cardiac and Respiratory Traces in Magnetic Resonance Imaging: A Review. IEEE Rev Biomed Eng 2021; 15:200-221. [PMID: 33513108 DOI: 10.1109/rbme.2021.3055550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Synchronization of human vital signs, namely the cardiac cycle and respiratory excursions, is necessary during magnetic resonance imaging of the cardiovascular system and the abdominal cavity to achieve optimal image quality with minimized artifacts. This review summarizes techniques currently available in clinical practice, as well as methods under development, outlines the benefits and disadvantages of each approach, and offers some unique solutions for consideration.
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ECG-gated MR angiography provides better reproducibility for standard aortic measurements. Eur Radiol 2021; 31:5087-5095. [PMID: 33409772 DOI: 10.1007/s00330-020-07408-1] [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: 06/15/2020] [Revised: 08/18/2020] [Accepted: 10/12/2020] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Cardiac motion and aortic pulsatility can affect the image quality of 3D contrast-enhanced MR angiography (CE-MRA). The addition of ECG gating improves image quality; however, no studies have directly linked image quality improvements to clinically used measures. In this study, we directly compared diameter measurements in the same patient from ECG-gated to non-gated CE-MRA to evaluate the impact of ECG gating upon measurement reproducibility. METHODS Fifty-three patients, referred for thoracic aortic angiography, were enrolled and underwent both non-gated and ECG-gated CE-MRA. Two readers independently measured vessel diameter, image quality, and vessel sharpness at the sinus of Valsalva (SOV), sinotubular junction (STJX), ascending aorta (AAO), distal aortic arch (DLSA), and descending aorta (DAO). Measurement reliability and reproducibility were compared between methods. RESULTS Image quality with ECG gating was rated significantly higher at the SOV (3.2 ± 0.9 vs 1.2 ± 1.0, p < 0.0001), STJX (3.4 ± 0.7 vs 1.8 ± 1.0, p < 0.0001), AAO (3.5 ± 0.6 vs 1.7 ± 1.1 p < 0.0001), DLSA (4.0 ± 0.1 vs 3.6 ± 0.7, p = 0.006), and DAO (4.0 ± 0.1 vs 3.4 ± 0.9 p < 0.0001) than for non-gated studies. Bland-Altman analyses demonstrated that inter- and intra-observer variability was significantly smaller for ECG-gated MRA at the SOV and AAO. For the non-gated images at the SOV, the 95% limits of agreement for both inter- and intra-observer variability exceeded the growth-rate cutoff for surgical repair (0.5 cm). At the DAO, variability was similar between the two techniques. CONCLUSION ECG-gated CE-MRA resulted in improved reproducibility in aortic root and ascending aortic measurements. These data suggest that ECG-gated CE-MRA should be used for the serial assessment of the ascending thoracic aorta. KEY POINTS • ECG-gated CE-MRA improves the reproducibility and repeatability of measurements of the ascending aorta. • With non-gated CE-MRA, pulsatile motion in the proximal aorta results in significant variability in measurement reproducibility.
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Antoni ST, Lehmann S, Neidhardt M, Fehrs K, Ruprecht C, Kording F, Adam G, Schupp S, Schlaefer A. Model checking for trigger loss detection during Doppler ultrasound-guided fetal cardiovascular MRI. Int J Comput Assist Radiol Surg 2018; 13:1755-1766. [PMID: 30078152 DOI: 10.1007/s11548-018-1832-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/25/2018] [Indexed: 11/26/2022]
Abstract
PURPOSE Ultrasound (US) is the state of the art in prenatal diagnosis to depict fetal heart diseases. Cardiovascular magnetic resonance imaging (CMRI) has been proposed as a complementary diagnostic tool. Currently, only trigger-based methods allow the temporal and spatial resolutions necessary to depict the heart over time. Of these methods, only Doppler US (DUS)-based triggering is usable with higher field strengths. DUS is sensitive to motion. This may lead to signal and, ultimately, trigger loss. If too many triggers are lost, the image acquisition is stopped, resulting in a failed imaging sequence. Moreover, losing triggers may prolong image acquisition. Hence, if no actual trigger can be found, injected triggers are added to the signal based on the trigger history. METHOD We use model checking, a technique originating from the computer science domain that formally checks if a model satisfies given requirements, to simultaneously model heart and respiratory motion and to decide whether respiration has a prominent effect on the signal. Using bounds on the physiological parameters and their variability, the method detects when changes in the signal are due to respiration. We use this to decide when to inject a trigger. RESULTS In a real-world scenario, we can reduce the number of falsely injected triggers by 94% from more than 87% to less than 5%. On a subset of motion that would allow CMRI, the number can be further reduced to below 0.2%. In a study using simulations with a robot, we show that our method works for different types of motions, motion ranges, starting positions and heartbeat traces. CONCLUSION While DUS is a promising approach for fetal CMRI, correct trigger injection is critical. Our model checking method can reduce the number of wrongly injected triggers substantially, providing a key prerequisite for fast and artifact free CMRI.
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Affiliation(s)
- Sven-Thomas Antoni
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany.
| | - Sascha Lehmann
- Institute for Software Systems, Hamburg University of Technology, Hamburg, Germany
| | - Maximilian Neidhardt
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany
| | - Kai Fehrs
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Ruprecht
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabian Kording
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerhard Adam
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sibylle Schupp
- Institute for Software Systems, Hamburg University of Technology, Hamburg, Germany
| | - Alexander Schlaefer
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany
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Li Y, Chen H, He L, Cao X, Wang X, Chen S, Li R, Yuan C. Hemodynamic assessments of venous pulsatile tinnitus using 4D-flow MRI. Neurology 2018; 91:e586-e593. [PMID: 29997192 DOI: 10.1212/wnl.0000000000005948] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/28/2018] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To use 4D-flow MRI to characterize hemodynamics of transverse and sigmoid sinus in venous pulsatile tinnitus (PT) patients and to investigate their differences vs healthy controls. METHODS A total of 21 patients with venous PT and 11 healthy controls were included in the retrospective study. All participants underwent 4D-flow and magnetic resonance venography scan in a 3.0T magnetic resonance scanner. All visualization, quantification, and analysis of 4D-flow data were performed using dedicated software. Two independent reviewers evaluated the existence of vortex or turbulence. Covariance analysis adjusted for age was used to compare average through-plane velocity (Vtp_avg), maximum through-plane velocity (Vtp_max), average velocity (Vavg), maximum velocity (Vmax), average blood flow (Flowavg), and pulsatility index (PI) between PT and control group. RESULTS There were hemodynamic differences between PT patients and healthy controls. Compared with the control group, the PT group showed significantly higher Vtp_avg, Vtp_max, Vavg, Vmax, and Flowavg, and slightly higher PI. For the assessment of flow pattern, inter-reader reproducibility was excellent (κ = 1.00). Vortex or turbulence was observed in PT patients with good sensitivity (86.4%) and specificity (90.9%). Drainage dominance was more frequently observed in patients (15/21, 71.4%) than healthy controls (4/11, 36.4%). CONCLUSIONS Significant hemodynamic differences were found between venous PT patients and healthy controls with 4D-flow MRI. Hemodynamic conditions could serve as noninvasive biomarkers for diagnosis and treatment evaluation of venous PT. CLASSIFICATION OF EVIDENCE This study provides Class III evidence that 4D-flow MRI accurately identifies patients with venous PT.
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Affiliation(s)
- Yunduo Li
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Huijun Chen
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Le He
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Xiangyu Cao
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Xianling Wang
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Shubin Chen
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
| | - Rui Li
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle.
| | - Chun Yuan
- From the Center for Biomedical Imaging Research (Y.L., H.C., L.H., R.L., C.Y.), Department of Biomedical Engineering, Tsinghua University; Neurosurgery Department (X.C.), PLA General Hospital; Xuanwu Hospital (X.W.), Capital Medical University; Beijing Tongren Hospital (S.C.), Capital Medical University, Beijing, China; and Department of Radiology (C.Y.), University of Washington, Seattle
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Stäb D, Roessler J, O'Brien K, Hamilton-Craig C, Barth M. ECG Triggering in Ultra-High Field Cardiovascular MRI. ACTA ACUST UNITED AC 2016; 2:167-174. [PMID: 30042961 PMCID: PMC6024401 DOI: 10.18383/j.tom.2016.00193] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cardiac magnetic resonance imaging at ultra-high field (B0 ≥ 7 T) potentially provides improved resolution and new opportunities for tissue characterization. Although an accurate synchronization of the acquisition to the cardiac cycle is essential, electrocardiogram (ECG) triggering at ultra-high field can be significantly impacted by the magnetohydrodynamic (MHD) effect. Blood flow within a static magnetic field induces a voltage, which superimposes the ECG and often affects the recognition of the R-wave. The MHD effect scales with B0 and is particularly pronounced at ultra-high field creating triggering-related image artifacts. Here, we investigated the performance of a conventional 3-lead ECG trigger device and a state-of-the-art trigger algorithm for cardiac ECG synchronization at 7 T. We show that by appropriate subject preparation and by including a learning phase for the R-wave detection outside of the magnetic field, reliable ECG triggering is feasible in healthy subjects at 7 T without additional equipment. Ultra-high field cardiac imaging was performed with the ECG signal and the trigger events recorded in 8 healthy subjects. Despite severe ECG signal distortions, synchronized imaging was successfully performed. Recorded ECG signals, vectorcardiograms, and large consistency in trigger event spacing indicate high accuracy for R-wave detection.
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Affiliation(s)
- Daniel Stäb
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia.,Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany
| | | | | | - Christian Hamilton-Craig
- Richard Slaughter Centre of Excellence in CVMRI, The Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Markus Barth
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
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11
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Kording F, Yamamura J, Lund G, Ueberle F, Jung C, Adam G, Schoennagel BP. Doppler Ultrasound Triggering for Cardiovascular MRI at 3T in a Healthy Volunteer Study. Magn Reson Med Sci 2016; 16:98-108. [PMID: 27001390 PMCID: PMC5600068 DOI: 10.2463/mrms.mp.2015-0104] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Purpose: Electrocardiogram (ECG) triggering for cardiac magnetic resonance (CMR) may be influenced by electromagnetic interferences with increasing magnetic field strength. The aim of this study was to evaluate the performance of Doppler ultrasound (DUS) as an alternative trigger technique for CMR in comparison to ECG and pulse oximetry (POX) at 3T and using different sequence types. Methods: Balanced turbo field echo two-dimensional (2D) short axis cine CMR and 2D phase-contrast angiography of the ascending aorta was performed in 11 healthy volunteers at 3T using ECG, DUS, and POX for cardiac triggering. DUS and POX triggering were compared to the reference standard of ECG in terms of trigger quality (trigger detection and temporal variability), image quality [endocardial blurring (EB)], and functional measurements [left ventricular (LV) volumetry and aortic blood flow velocimetry]. Results: Trigger signal detection and temporal variability did not differ significantly between ECG/DUS (I = 0.6) and ECG/POX (P = 0.4). Averaged EB was similar for ECG, DUS, and POX (pECG/DUS = 0.4, pECG/POX = 0.9). Diastolic EB was significantly decreased for DUS in comparison to ECG (P = 0.02) and POX (P = 0.04). The LV function assessment and aortic blood flow were not significantly different. Conclusion: This study demonstrated the feasibility of DUS for gating human CMR at 3T. The magnetohydrodynamic effect did not significantly disturb ECG triggering in this small healthy volunteer study. DUS showed a significant improvement in diastolic EB but could not be identified as a superior trigger method. The potential benefit of DUS has to be evaluated in a larger clinical patient population.
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Affiliation(s)
- Fabian Kording
- University Medical Center Hamburg-Eppendorf, Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf
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12
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Niendorf T, Schulz-Menger J. [Cardiovascular ultrahigh field magnetic resonance imaging : challenges, technical solutions and opportunities]. Radiologe 2014; 53:422-8. [PMID: 23613023 DOI: 10.1007/s00117-012-2348-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
CLINICAL/METHODICAL ISSUE This involves high spatial resolution cardiac imaging with ultrahigh magnetic fields (7 T) and clinically acceptable image quality. STANDARD RADIOLOGICAL METHODS Cardiovascular magnetic resonance imaging (MRI) at a field strength of 1.5 T using a spatial resolution of (2 × 2 × 6-8) mm(3). METHODICAL INNOVATIONS Cardiac MRI at ultrahigh field strength makes use of multitransmit/receive radiofrequency (RF) technology and development of novel technology that utilizes the traits of ultrahigh field MRI. PERFORMANCE Enhanced spatial resolution which is superior by a factor of 6-10 to what can be achieved by current clinical cardiac MRI. The relative spatial resolution (pixels per anatomical structure) comes close to what can be accomplished by current cardiac MRI in small rodents. ACHIEVEMENTS Feasibility studies demonstrate the gain in spatial resolution at 7.0 T due to the sensitivity advantage inherent to ultrahigh magnetic fields. PRACTICAL RECOMMENDATIONS Please stay tuned and please put further weight behind the solution of the remaining technical problems of cardiac MRI at 7.0 T.
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Affiliation(s)
- T Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13125, Berlin, Deutschland.
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13
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Current world literature. Curr Opin Cardiol 2012; 27:556-64. [PMID: 22874129 DOI: 10.1097/hco.0b013e32835793f0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Fushimi Y, Okada T, Yamamoto A, Kanagaki M, Imai H, Togashi K. Estimation of the timing of carotid artery flow using peripheral pulse wave-gated MRI. J Magn Reson Imaging 2012; 36:454-8. [PMID: 22517508 DOI: 10.1002/jmri.23665] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/07/2012] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To investigate the relationship between peripheral pulse wave (PPW)-gating and the carotid systolic pulse wave in a large clinical patient cohort, and to establish a process for correct estimation of delay time from PPW-gating to foot (ie, beginning) or peak times of carotid systolic pulse waves. MATERIALS AND METHODS Subjects comprised 209 patients scanned using 3T magnetic resonance imaging (MRI) for PPW-gated phase contrast images at the common carotid artery. Stepwise multiple regression analysis was conducted for the relationship between foot or peak times and the following factors after excluding correlated factors with coefficients ≥0.5: pulse rate (PR); systolic blood pressure; diastolic blood pressure; height; body weight; body mass index; Brinkman index; diabetes mellitus; hypertension; and hyperlipidemia. RESULTS PR showed significant correlation with foot (r = -0.86, P < 0.001) and peak (r = -0.87, P < 0.001) times. The following equations were derived: foot time (msec) = -8.55 × PR + 993.1 and peak time (msec) = -9.21 × PR + 1142.3. No other factors showed significant correlations. CONCLUSION PR was the only factor showing significant relationships to foot and peak times of carotid artery flow. The derived equations will facilitate various kinds of noncontrast MR acquisition with simple PPW-gating.
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Affiliation(s)
- Yasutaka Fushimi
- Department of Radiology, Ichinomiyanishi Hospital, Ichinomiya, Japan.
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