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Aramendía-Vidaurreta V, Solís-Barquero SM, Vidorreta M, Ezponda A, Echeverria-Chasco R, Bastarrika G, Fernández-Seara MA. Comparison of Myocardial Blood Flow Quantification Models for Double ECG Gating Arterial Spin Labeling MRI: Reproducibility Assessment. J Magn Reson Imaging 2024. [PMID: 38206090 DOI: 10.1002/jmri.29220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Arterial spin labeling (ASL) allows non-invasive quantification of myocardial blood flow (MBF). Double-ECG gating (DG) ASL is more robust to heart rate variability than single-ECG gating (SG), but its reproducibility requires further investigation. Moreover, the existence of multiple quantification models hinders its application. Frequency-offset-corrected-inversion (FOCI) pulses provide sharper edge profiles than hyperbolic-secant (HS), which could benefit myocardial ASL. PURPOSE To assess the performance of MBF quantification models for DG compared to SG ASL, to evaluate their reproducibility and to compare the effects of HS and FOCI pulses. STUDY TYPE Prospective. SUBJECTS Sixteen subjects (27 ± 8 years). FIELD STRENGTH/SEQUENCE 1.5 T/DG and SG flow-sensitive alternating inversion recovery ASL. ASSESSMENT Three models for DG MBF quantification were compared using Monte Carlo simulations and in vivo experiments. Two models used a fitting approach (one using only a single label and control image pair per fit, the other using all available image pairs), while the third model used a T1 correction approach. Slice profile simulations were conducted for HS and FOCI pulses with varying B0 and B1. Temporal signal-to-noise ratio (tSNR) was computed for different acquisition/quantification strategies and inversion pulses. The number of images that minimized MBF error was investigated in the model with highest tSNR. Intra and intersession reproducibility were assessed in 10 subjects. STATISTICAL TESTS Within-subject coefficient of variation, analysis of variance. P-value <0.05 was considered significant. RESULTS MBF was not different across acquisition/quantification strategies (P = 0.27) nor pulses (P = 0.9). DG MBF quantification models exhibited significantly higher tSNR and superior reproducibility, particularly for the fitting model using multiple images (tSNR was 3.46 ± 2.18 in vivo and 3.32 ± 1.16 in simulations, respectively; wsCV = 16%). Reducing the number of ASL pairs to 13/15 did not increase MBF error (minimum = 0.22 mL/g/min). DATA CONCLUSION Reproducibility of MBF was better for DG than SG acquisitions, especially when employing a fitting model. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Verónica Aramendía-Vidaurreta
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Sergio M Solís-Barquero
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | | | - Ana Ezponda
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Rebeca Echeverria-Chasco
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Gorka Bastarrika
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - María A Fernández-Seara
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
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Božić‐Iven M, Rapacchi S, Tao Q, Pierce I, Thornton G, Nitsche C, Treibel TA, Schad LR, Weingärtner S. Improved reproducibility for myocardial ASL: Impact of physiological and acquisition parameters. Magn Reson Med 2024; 91:118-132. [PMID: 37667643 PMCID: PMC10962577 DOI: 10.1002/mrm.29834] [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: 08/07/2022] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 09/06/2023]
Abstract
PURPOSE To investigate and mitigate the influence of physiological and acquisition-related parameters on myocardial blood flow (MBF) measurements obtained with myocardial Arterial Spin Labeling (myoASL). METHODS A Flow-sensitive Alternating Inversion Recovery (FAIR) myoASL sequence with bSSFP and spoiled GRE (spGRE) readout is investigated for MBF quantification. Bloch-equation simulations and phantom experiments were performed to evaluate how variations in acquisition flip angle (FA), acquisition matrix size (AMS), heart rate (HR) and bloodT 1 $$ {\mathrm{T}}_1 $$ relaxation time (T 1 , B $$ {\mathrm{T}}_{1,B} $$ ) affect quantification of myoASL-MBF. In vivo myoASL-images were acquired in nine healthy subjects. A corrected MBF quantification approach was proposed based on subject-specificT 1 , B $$ {\mathrm{T}}_{1,B} $$ values and, for spGRE imaging, subtracting an additional saturation-prepared baseline from the original baseline signal. RESULTS Simulated and phantom experiments showed a strong dependence on AMS and FA (R 2 $$ {R}^2 $$ >0.73), which was eliminated in simulations and alleviated in phantom experiments using the proposed saturation-baseline correction in spGRE. Only a very mild HR dependence (R 2 $$ {R}^2 $$ >0.59) was observed which was reduced when calculating MBF with individualT 1 , B $$ {\mathrm{T}}_{1,B} $$ . For corrected spGRE, in vivo mean global spGRE-MBF ranged from 0.54 to 2.59 mL/g/min and was in agreement with previously reported values. Compared to uncorrected spGRE, the intra-subject variability within a measurement (0.60 mL/g/min), between measurements (0.45 mL/g/min), as well as the inter-subject variability (1.29 mL/g/min) were improved by up to 40% and were comparable with conventional bSSFP. CONCLUSION Our results show that physiological and acquisition-related factors can lead to spurious changes in myoASL-MBF if not accounted for. Using individualT 1 , B $$ {\mathrm{T}}_{1,B} $$ and a saturation-baseline can reduce these variations in spGRE and improve reproducibility of FAIR-myoASL against acquisition parameters.
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Affiliation(s)
- Maša Božić‐Iven
- Medical Faculty MannheimHeidelberg UniversityMannheimGermany
- Department of Imaging PhysicsDelft University of TechnologyDelftThe Netherlands
| | | | - Qian Tao
- Department of Imaging PhysicsDelft University of TechnologyDelftThe Netherlands
| | - Iain Pierce
- Barts Heart CentreSt Bartholomew's HospitalLondonUK
| | - George Thornton
- Barts Heart CentreSt Bartholomew's HospitalLondonUK
- Institute of Cardiovascular ScienceUniversity College LondonLondonUK
| | - Christian Nitsche
- Barts Heart CentreSt Bartholomew's HospitalLondonUK
- Institute of Cardiovascular ScienceUniversity College LondonLondonUK
- Division of CardiologyMedical University of ViennaViennaAustria
| | - Thomas A. Treibel
- Barts Heart CentreSt Bartholomew's HospitalLondonUK
- Institute of Cardiovascular ScienceUniversity College LondonLondonUK
| | - Lothar R. Schad
- Medical Faculty MannheimHeidelberg UniversityMannheimGermany
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Taso M, Aramendía-Vidaurreta V, Englund EK, Francis S, Franklin S, Madhuranthakam AJ, Martirosian P, Nayak KS, Qin Q, Shao X, Thomas DL, Zun Z, Fernández-Seara MA. Update on state-of-the-art for arterial spin labeling (ASL) human perfusion imaging outside of the brain. Magn Reson Med 2023; 89:1754-1776. [PMID: 36747380 DOI: 10.1002/mrm.29609] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/09/2023] [Accepted: 01/16/2023] [Indexed: 02/08/2023]
Abstract
This review article provides an overview of developments for arterial spin labeling (ASL) perfusion imaging in the body (i.e., outside of the brain). It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. In this review, we focus on specific challenges and developments tailored for ASL in a variety of body locations. After presenting common challenges, organ-specific reviews of challenges and developments are presented, including kidneys, lungs, heart (myocardium), placenta, eye (retina), liver, pancreas, and muscle, which are regions that have seen the most developments outside of the brain. Summaries and recommendations of acquisition parameters (when appropriate) are provided for each organ. We then explore the possibilities for wider adoption of body ASL based on large standardization efforts, as well as the potential opportunities based on recent advances in high/low-field systems and machine-learning. This review seeks to provide an overview of the current state-of-the-art of ASL for applications in the body, highlighting ongoing challenges and solutions that aim to enable more widespread use of the technique in clinical practice.
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Affiliation(s)
- Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Erin K Englund
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Susan Francis
- Sir Peter Mansfield Imaging Center, University of Nottingham, Nottingham, UK
| | - Suzanne Franklin
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
- Center for Image Sciences, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ananth J Madhuranthakam
- Department of Radiology, Advanced Imaging Research Center, and Biomedical Engineering, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Petros Martirosian
- Section on Experimental Radiology, Department of Radiology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Zungho Zun
- Department of Radiology, Weill Cornell Medicine, New York, New York, USA
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Hatakeyama N, Kobayashi S. Development and practical evaluation of a saturation effect learning simulator for inflow magnetic resonance angiography. Radiol Phys Technol 2022; 15:311-322. [PMID: 36002782 DOI: 10.1007/s12194-022-00671-5] [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: 01/20/2022] [Revised: 08/05/2022] [Accepted: 08/06/2022] [Indexed: 11/25/2022]
Abstract
The quality of visualization in inflow magnetic resonance angiography (MRA) depends highly on the excitation state of the longitudinal magnetization obtained using specified imaging parameters. In addition, signal intensity changes controlled by the preparation pulse-such as inversion recovery (IR) and saturation recovery (SR)-can potentially be used as quantitative physiological values. Although having practitioners understand these relationships both qualitatively and quantitatively is important, handling clinical equipment in practical learning or experiments involves limited opportunities. The simulator corresponds to a three-dimensional spoiled gradient echo sequence and allows users to freely input multiple virtual excitation effects in space and time. The purpose of this study was to quantitatively evaluate the agreement between the measured MRAs obtained in flow phantom tests and virtual MRAs simulated under similar conditions. We imaged two vascular flow phantoms on a 3.0 T MR system using three-dimensional (3D) time-of-flight (TOF) MRA and 3D inversion recovery tissue signal suppression (IR-suppression) MRA protocols. We evaluated quantitative values for consistency between the measured and virtual MRAs images with matched spatial resolution. Then we assessed the coincidence by reformatting maximum-intensity projection images with 1 mm isotropic pixels, with it ranging from 89.6 to 92.0% and 89.1 to 92.9% for TOF MRA and IR-suppression MRA, respectively. These results may be useful as a reference index for the theoretical study of MRA images by practitioners, for complementary validation by phantom testing, or for the development of MRI-related simulators.
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Affiliation(s)
- Norishige Hatakeyama
- Nagano Chuo Hospital, 1570 Nishi-Tsuruga, Nagano, 380-0814, Japan.
- Graduate School of Medicine, Science and Technology, Shinshu University, Matsumoto, Japan.
| | - Shunichi Kobayashi
- Graduate School of Medicine, Science and Technology, Shinshu University, Matsumoto, Japan
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Ismail TF, Strugnell W, Coletti C, Božić-Iven M, Weingärtner S, Hammernik K, Correia T, Küstner T. Cardiac MR: From Theory to Practice. Front Cardiovasc Med 2022; 9:826283. [PMID: 35310962 PMCID: PMC8927633 DOI: 10.3389/fcvm.2022.826283] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/17/2022] [Indexed: 01/10/2023] Open
Abstract
Cardiovascular disease (CVD) is the leading single cause of morbidity and mortality, causing over 17. 9 million deaths worldwide per year with associated costs of over $800 billion. Improving prevention, diagnosis, and treatment of CVD is therefore a global priority. Cardiovascular magnetic resonance (CMR) has emerged as a clinically important technique for the assessment of cardiovascular anatomy, function, perfusion, and viability. However, diversity and complexity of imaging, reconstruction and analysis methods pose some limitations to the widespread use of CMR. Especially in view of recent developments in the field of machine learning that provide novel solutions to address existing problems, it is necessary to bridge the gap between the clinical and scientific communities. This review covers five essential aspects of CMR to provide a comprehensive overview ranging from CVDs to CMR pulse sequence design, acquisition protocols, motion handling, image reconstruction and quantitative analysis of the obtained data. (1) The basic MR physics of CMR is introduced. Basic pulse sequence building blocks that are commonly used in CMR imaging are presented. Sequences containing these building blocks are formed for parametric mapping and functional imaging techniques. Commonly perceived artifacts and potential countermeasures are discussed for these methods. (2) CMR methods for identifying CVDs are illustrated. Basic anatomy and functional processes are described to understand the cardiac pathologies and how they can be captured by CMR imaging. (3) The planning and conduct of a complete CMR exam which is targeted for the respective pathology is shown. Building blocks are illustrated to create an efficient and patient-centered workflow. Further strategies to cope with challenging patients are discussed. (4) Imaging acceleration and reconstruction techniques are presented that enable acquisition of spatial, temporal, and parametric dynamics of the cardiac cycle. The handling of respiratory and cardiac motion strategies as well as their integration into the reconstruction processes is showcased. (5) Recent advances on deep learning-based reconstructions for this purpose are summarized. Furthermore, an overview of novel deep learning image segmentation and analysis methods is provided with a focus on automatic, fast and reliable extraction of biomarkers and parameters of clinical relevance.
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Affiliation(s)
- Tevfik F. Ismail
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Cardiology Department, Guy's and St Thomas' Hospital, London, United Kingdom
| | - Wendy Strugnell
- Queensland X-Ray, Mater Hospital Brisbane, Brisbane, QLD, Australia
| | - Chiara Coletti
- Magnetic Resonance Systems Lab, Delft University of Technology, Delft, Netherlands
| | - Maša Božić-Iven
- Magnetic Resonance Systems Lab, Delft University of Technology, Delft, Netherlands
- Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany
| | | | - Kerstin Hammernik
- Lab for AI in Medicine, Technical University of Munich, Munich, Germany
- Department of Computing, Imperial College London, London, United Kingdom
| | - Teresa Correia
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Centre of Marine Sciences, Faro, Portugal
| | - Thomas Küstner
- Medical Image and Data Analysis (MIDAS.lab), Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, Germany
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Aramendía-Vidaurreta V, Gordaliza PM, Vidorreta M, Echeverría-Chasco R, Bastarrika G, Muñoz-Barrutia A, Fernández-Seara MA. Reduction of motion effects in myocardial arterial spin labeling. Magn Reson Med 2021; 87:1261-1275. [PMID: 34644410 DOI: 10.1002/mrm.29038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/09/2021] [Accepted: 09/20/2021] [Indexed: 11/09/2022]
Abstract
PURPOSE To evaluate the accuracy and reproducibility of myocardial blood flow measurements obtained under different breathing strategies and motion correction techniques with arterial spin labeling. METHODS A prospective cardiac arterial spin labeling study was performed in 12 volunteers at 3 Tesla. Perfusion images were acquired twice under breath-hold, synchronized-breathing, and free-breathing. Motion detection based on the temporal intensity variation of a myocardial voxel, as well as image registration based on pairwise and groupwise approaches, were applied and evaluated in synthetic and in vivo data. A region of interest was drawn over the mean perfusion-weighted image for quantification. Original breath-hold datasets, analyzed with individual regions of interest for each perfusion-weighted image, were considered as reference values. RESULTS Perfusion measurements in the reference breath-hold datasets were in line with those reported in literature. In original datasets, prior to motion correction, myocardial blood flow quantification was significantly overestimated due to contamination of the myocardial perfusion with the high intensity signal of blood pool. These effects were minimized with motion detection or registration. Synthetic data showed that accuracy of the perfusion measurements was higher with the use of registration, in particular after the pairwise approach, which probed to be more robust to motion. CONCLUSION Satisfactory results were obtained for the free-breathing strategy after pairwise registration, with higher accuracy and robustness (in synthetic datasets) and higher intrasession reproducibility together with lower myocardial blood flow variability across subjects (in in vivo datasets). Breath-hold and synchronized-breathing after motion correction provided similar results, but these breathing strategies can be difficult to perform by patients.
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Affiliation(s)
- Verónica Aramendía-Vidaurreta
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Pedro M Gordaliza
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | | | - Rebeca Echeverría-Chasco
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Gorka Bastarrika
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Arrate Muñoz-Barrutia
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - María A Fernández-Seara
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
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7
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Zun Z, Kapse K, Jacobs M, Basu S, Said M, Andersen N, Murnick J, Chang T, du Plessis A, Limperopoulos C. Longitudinal Trajectories of Regional Cerebral Blood Flow in Very Preterm Infants during Third Trimester Ex Utero Development Assessed with MRI. Radiology 2021; 299:691-702. [PMID: 33787337 DOI: 10.1148/radiol.2021202423] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background The third trimester of gestation is a crucial phase of rapid brain development, but little has been reported on the trajectories of cerebral blood flow (CBF) in preterm infants in this period. Purpose To quantify regional CBF in very preterm infants longitudinally across the ex utero third trimester and to determine its relationship with clinical factors associated with brain injury and premature birth. Materials and Methods In this prospective study, very preterm infants were enrolled for three longitudinal MRI scans, and 22 healthy full-term infants were enrolled for one term MRI scan between November 2016 and February 2019. Global and regional CBF in the cortical gray matter, white matter, deep gray matter, and cerebellum were measured using arterial spin labeling with postlabeling delay of 2025 msec at 1.5 T and 3.0 T. Brain injury and clinical risk factors in preterm infants were investigated to determine associations with CBF. Generalized estimating equations were used to account for correlations between repeated measures in the same individual. Results A total of 75 preterm infants (mean postmenstrual age [PMA]: 29.5 weeks ± 2.3 [standard deviation], 34.9 weeks ± 0.8, and 39.3 weeks ± 2.0 for each scan; 43 male infants) and 22 full-term infants (mean PMA, 42.1 weeks ± 2.0; 13 male infants) were evaluated. In preterm infants, global CBF was 11.9 mL/100 g/min ± 0.2 (standard error). All regional CBF increased significantly with advancing PMA (P ≤ .02); the cerebellum demonstrated the most rapid CBF increase and the highest mean CBF. Lower CBF was associated with intraventricular hemorrhage in all regions (P ≤ .05) and with medically managed patent ductus arteriosus in the white matter and deep gray matter (P = .03). Mean CBF of preterm infants at term-equivalent age was significantly higher compared with full-term infants (P ≤ .02). Conclusion Regional cerebral blood flow increased significantly in preterm infants developing in an extrauterine environment across the third trimester and was associated with intraventricular hemorrhage and patent ductus arteriosus. © RSNA, 2021 Online supplemental material is available for this article.
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Affiliation(s)
- Zungho Zun
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Kushal Kapse
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Marni Jacobs
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Sudeepta Basu
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Mariam Said
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Nicole Andersen
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Jonathan Murnick
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Taeun Chang
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Adre du Plessis
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
| | - Catherine Limperopoulos
- From the Division of Diagnostic Imaging and Radiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010 (Z.Z., K.K., N.A., J.M., C.L.); Division of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC (Z.Z., A.d.P., C.L.); Departments of Pediatrics (Z.Z., M.J., S.B., M.S., J.M., T.C., A.d.P., C.L.) and Radiology (Z.Z., J.M., C.L.) and Divisions of Neonatology (S.B., M.S.) and Neurology (T.C.), Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC; Division of Biostatistics and Study Methodology, Children's National Research Institute, Washington, DC (M.J.)
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Henningsson M, Carlhäll C, Kihlberg J. Myocardial arterial spin labeling in systole and diastole using flow-sensitive alternating inversion recovery with parallel imaging and compressed sensing. NMR IN BIOMEDICINE 2021; 34:e4436. [PMID: 33150707 PMCID: PMC7816237 DOI: 10.1002/nbm.4436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Quantitative myocardial perfusion can be achieved without contrast agents using flow-sensitive alternating inversion recovery (FAIR) arterial spin labeling. However, FAIR has an intrinsically low sensitivity, which may be improved by mitigating the effects of physiological noise or by increasing the area of artifact-free myocardium. The aim of this study was to investigate if systolic FAIR may increase the amount of analyzable myocardium compared with diastolic FAIR and its effect on physiological noise. Furthermore, we compare parallel imaging acceleration with a factor of 2 with compressed sensing acceleration with a factor of 3 for systolic FAIR. Twelve healthy subjects were scanned during rest on a 3 T scanner using diastolic FAIR with parallel imaging factor 2 (FAIR-PI2D ), systolic FAIR with the same acceleration (FAIR-PI2S ) and systolic FAIR with compressed sensing factor 3 (FAIR-CS3S ). The number of analyzable pixels in the myocardium, temporal signal-to-noise ratio (TSNR) and mean myocardial blood flow (MBF) were calculated for all methods. The number of analyzable pixels using FAIR-CS3S (663 ± 55) and FAIR-PI2S (671 ± 58) was significantly higher than for FAIR-PI2D (507 ± 82; P = .001 for both), while there was no significant difference between FAIR-PI2S and FAIR-CS3S . The mean TSNR of the midventricular slice for FAIR-PI2D was 11.4 ± 3.9, similar to that of FAIR-CS3S, which was 11.0 ± 3.3, both considerably higher than for FAIR-PI2S, which was 8.4 ± 3.1 (P < .05 for both). Mean MBF was similar for all three methods. The use of compressed sensing accelerated systolic FAIR benefits from an increased number of analyzable myocardial pixels compared with diastolic FAIR without suffering from a TSNR penalty, unlike systolic FAIR with parallel imaging acceleration.
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Affiliation(s)
- Markus Henningsson
- Unit for Cardiovascular Sciences, Department of Health, Medicine and Caring SciencesLinköping UniversityLinköpingSweden
- Center for Medical Image Science and Visualization (CMIV)Linköping UniversityLinköpingSweden
- School of Biomedical Engineering and Imaging SciencesKing's College LondonLondonUK
| | - Carl‐Johan Carlhäll
- Unit for Cardiovascular Sciences, Department of Health, Medicine and Caring SciencesLinköping UniversityLinköpingSweden
- Center for Medical Image Science and Visualization (CMIV)Linköping UniversityLinköpingSweden
- Department of Clinical Physiology in Linköping, Department of Health, Medicine and Caring SciencesLinköping UniversityLinköpingSweden
| | - Johan Kihlberg
- Center for Medical Image Science and Visualization (CMIV)Linköping UniversityLinköpingSweden
- Department of Radiology, Department of Health, Medicine and Caring SciencesLinköping UniversityLinköpingSweden
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Aramendía-Vidaurreta V, Echeverría-Chasco R, Vidorreta M, Bastarrika G, Fernández-Seara MA. Quantification of Myocardial Perfusion With Vasodilation Using Arterial Spin Labeling at 1.5T. J Magn Reson Imaging 2020; 53:777-788. [PMID: 33063433 DOI: 10.1002/jmri.27396] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Myocardial perfusion is evaluated in first-pass MRI using a gadolinium-based contrast agent, which limits its repeatability and restricts its use in patients with abnormal kidney function. Arterial spin labeling (ASL) is a promising technique for measuring myocardial perfusion without contrast injection. The ratio of stress to rest perfusion, termed myocardial perfusion reserve (MPR), is an indicator of the severity of stenosis in patients with coronary artery disease (CAD). PURPOSE To quantify perfusion increases with pharmacological vasodilation, explore MPR differences between segments with and without perfusion defects, and examine the correlations between quantitative ASL and semiquantitative first-pass measurements. STUDY TYPE Prospective. SUBJECTS Sixteen patients with suspected CAD: 10 classified as "healthy," having normal perfusion on first-pass and no enhancement on late gadolinium enhancement (LGE), and six as "nonhealthy," having hypoperfused segments including ischemic and infarcted. FIELD STRENGTH/SEQUENCE Flow-sensitive alternating inversion recovery (FAIR) rest-stress cardiac ASL with balanced steady-state free precession (bSSFP), rest-stress first-pass imaging using gradient-echo and LGE using a phase-sensitive inversion-recovery bSSFP at 1.5T. ASSESSMENT For healthy subjects, rest-stress perfusion data were compared in global, coronary artery territory, and segment regions of interest (ROIs). A segmental MPR comparison was performed between normal segments from healthy subjects and abnormal segments from nonhealthy subjects. Correlations between ASL and first-pass parameters were explored. STATISTICAL TESTS Wilcoxon-signed-rank test, nonparametric factorial analysis of variance (ANOVA), and Pearson's/Spearman's correlations. RESULTS Perfusion increases were significant globally (P = 0.005), per coronary artery territory (P = 0.015), and per segment (P = 0.03 for all segments in ASL and first-pass, except anteroseptal in ASL P = 0.04). MPR differences between normal and abnormal segments were significant (P = 0.0028: ASL, P = 0.033: first-pass). ASL and first-pass measurements were correlated (MPR: r = 0.64, P = 0.008 and perfusion: rho = 0.47, P = 0.007). DATA CONCLUSION This study demonstrates the feasibility of ASL to detect hyperemia, the potential to differentiate segments with and without perfusion defects, and significant correlations between ASL and semiquantitative first-pass. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Verónica Aramendía-Vidaurreta
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Rebeca Echeverría-Chasco
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | | | - Gorka Bastarrika
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - María A Fernández-Seara
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
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Lee NG, Javed A, Jao TR, Nayak KS. Numerical approximation to the general kinetic model for ASL quantification. Magn Reson Med 2020; 84:2846-2857. [PMID: 32367574 DOI: 10.1002/mrm.28304] [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: 01/16/2020] [Revised: 03/19/2020] [Accepted: 04/08/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE To develop a numerical approximation to the general kinetic model for arterial spin labeling (ASL) quantification that will enable greater flexibility in ASL acquisition methods. THEORY The Bloch-McConnell equations are extended to include the effects of single-compartment inflow and outflow on both the transverse and longitudinal magnetization. These can be solved using an extension of Jaynes' matrix formalism with piecewise constant approximation of incoming labeled arterial flow and a clearance operator for outgoing venous flow. METHODS The proposed numerical approximation is compared with the general kinetic model using simulations of pulsed labeling and pseudo-continuous labeling and a broad range of transit time and bolus duration for tissue blood flow of 0.6 mL/g/min. Accuracy of the approximation is studied as a function of the timestep using Monte-Carlo simulations. Three additional scenarios are demonstrated: (1) steady-pulsed ASL, (2) MR fingerprinting ASL, and (3) balanced SSFP and spoiled gradient-echo sequences. RESULTS The proposed approximation was found to be arbitrarily accurate for pulsed labeling and pseudo-continuous labeling. The pulsed labeling/pseudo-continuous labeling approximation error compared with the general kinetic model was less than 0.002% (<0.002%) and less than 0.05% (<0.05%) for timesteps of 3 ms and 35 ms, respectively. The proposed approximation matched well with customized signal expressions of steady-pulsed ASL and MR fingerprinting ASL. The simulations of simultaneous modeling of flow, T2 , and magnetization transfer showed an increase in steady-state balanced SSFP and spoiled gradient signals. CONCLUSION We demonstrate a numerical approximation of the "Bloch-McConnell flow" equations that enables arbitrarily accurate modeling of pulsed ASL and pseudo-continuous labeling signals comparable to the general kinetic model. This enables increased flexibility in the experiment design for quantitative ASL.
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Affiliation(s)
- Nam G Lee
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Ahsan Javed
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Terrence R Jao
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
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Landes V, Javed A, Jao T, Qin Q, Nayak K. Improved velocity-selective labeling pulses for myocardial ASL. Magn Reson Med 2020; 84:1909-1918. [PMID: 32173909 DOI: 10.1002/mrm.28253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 12/23/2022]
Abstract
PURPOSE To develop and evaluate an improved velocity-selective (VS) labeling pulse for myocardial arterial spin labeling (ASL) perfusion imaging that addresses two limitations of current pulses: (1) spurious labeling of moving myocardium and (2) low labeling efficiency. METHODS The proposed myocardial VSASL labeling pulse is designed using a Fourier Transform based Velocity-Selective labeling pulse train. The pulse utilizes bipolar velocity-encoding gradients, a 9-tap velocity-encoding envelope, and double-refocusing pulses with Malcolm Levitt phase cycling. Amplitudes of the velocity-encoding envelope were optimized to minimize the labeling of myocardial velocities during stable diastole (±2-3 cm/s) and maximize the labeling of coronary velocities (10-130 cm/s during rest/stress or 10-70 cm/s during rest). Myocardial ASL experiments were performed in seven healthy subjects using the previously developed VS-ASL protocol by Jao et al with the two proposed VS pulses and original VS pulse. Myocardial ASL experiments were also performed using FAIR ASL. Myocardial perfusion and physiological noise (PN) were evaluated and compared. RESULTS Bloch simulations of the first and second proposed pulses show <2% labeling over ±3 cm/s and ±2 cm/s, respectively. Bloch simulations also show the mean labeling efficiency of arterial blood is 1.23 over the relevant coronary arterial ranges. In-vivo VSASL experiments show the proposed pulses provided comparable measurements to FAIR ASL and reduced TSNR in 5 of 7 subjects compared to the original VS pulse. CONCLUSION We demonstrate an improved VS labeling pulse specifically for myocardial ASL perfusion imaging to reduce spurious labeling of moving myocardium and PN.
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Affiliation(s)
- Vanessa Landes
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
| | - Ahsan Javed
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
| | - Terrence Jao
- Keck School of Medicine, University of Southern California, Los Angles, CA, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, John Hopkins University School of Medicine, Baltimore, MD, USA.,F.M. Kirby Research Center for Functional Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Krishna Nayak
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA.,Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
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12
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Nakamori S, Fahmy A, Jang J, El-Rewaidy H, Neisius U, Berg S, Goddu B, Pierce P, Rodriguez J, Hauser T, Ngo LH, Manning WJ, Nezafat R. Changes in Myocardial Native T1 and T2 After Exercise Stress. JACC Cardiovasc Imaging 2020; 13:667-680. [DOI: 10.1016/j.jcmg.2019.05.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 02/01/2023]
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13
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Javed A, Nayak KS. Single-shot EPI for ASL-CMR. Magn Reson Med 2020; 84:738-750. [PMID: 32060949 DOI: 10.1002/mrm.28165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 11/23/2019] [Accepted: 12/15/2019] [Indexed: 01/08/2023]
Abstract
PURPOSE To evaluate single-shot echo planar imaging (SS-EPI), as an alternative to snapshot balanced steady state free precession (bSSFP) imaging, for arterial-spin-labeled cardiac MR (ASL-CMR). This study presents a practical implementation SS-EPI tailored to the needs of ASL-CMR at 3T and demonstrates sequential multi-slice ASL with no increase in scan time. METHODS Reduced field of view SS-EPI was performed using a 2DRF pulse. A spin-echo was used with crushers optimized to maximize blood suppression and minimize myocardial signal loss, based on experiments in 4 healthy volunteers. SS-EPI was evaluated against the widely used bSSFP reference method in single-slice ASL-CMR in 4 healthy volunteers, during both systole and diastole. Sequential multi-slice ASL-CMR with SS-EPI was demonstrated during diastole (3 slices: basal, mid, and apical short-axis) and during systole (2 slices: mid and apical short-axis), in 3 volunteers. RESULTS Global myocardial perfusion for diastolic SS-EPI (1.66 ± 0.73 mL/g/min) and systolic SS-EPI (1.50 ± 0.36 mL/g/min) were found to be statistically equivalent (2 one-sided test with a difference of 0.4 mL/g/min) to diastolic bSSFP (duration of 1 cardiac cycle, 1.60 ± 0.80 mL/g/min) with P-values of 0.022 and 0.031, respectively. Global myocardial perfusion for sequential multi-slice experiments was 1.64 ± 0.47, 1.34 ± 0.29, and 1.88 ± 0.58 for basal, mid, and apical SAX slices during diastole and was 1.61 ± 0.35, and 1.66 ± 0.49 for mid and apical slice during systole. These values are comparable to published ASL-CMR and positron emission tomography studies. CONCLUSION SS-EPI is a promising alternative to bSSFP imaging for ASL-CMR and can potentially improve the spatial coverage of ASL-CMR by 3-fold during diastole and 2-fold during systole, without increasing scan time.
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Affiliation(s)
- Ahsan Javed
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California
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14
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Javed A, Yoon A, Cen S, Nayak KS, Garg P. Feasibility of coronary endothelial function assessment using arterial spin labeled CMR. NMR IN BIOMEDICINE 2020; 33:e4183. [PMID: 31799707 PMCID: PMC6980265 DOI: 10.1002/nbm.4183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Coronary endothelial dysfunction (CED) is an independent predictor of cardiovascular disease, but its assessment has been limited to invasive coronary angiography. Myocardial perfusion imaging using arterial spin labeled (ASL) cardiac magnetic resonance (CMR) may be an effective non-invasive alternative for detection of CED. Thirty-four patients were recruited: 10 healthy volunteers, 13 at high-risk for coronary artery disease (CAD), and 11 with established CAD. ASL-CMR was performed continuously in a single mid-short axis slice during rest, stress, and recovery. Stress was induced with sustained isometric handgrip exercise, an endothelial dependent stressor. Myocardial perfusion (MP) during rest, peak stress, and recovery were calculated and compared. After excluding subjects unable to complete the protocol or who exhibited poor data quality, 6 healthy, 10 high-risk, and 7 CAD patients were included in the analysis. Average MP (ml/g/min) was 1.31 ± 1.23, 1.61 ± 1.12, and 1.40 ± 0.97 at rest, and 1.64 ± 1.49, 2.31 ± 1.61, and 2.84 ± 1.77 during stress, for the CAD, high-risk and healthy group, respectively. The average MP response (MPstress - MPrest , ml/g/min) was 0.32 ± 1.93, 0.69 ± 1.34, and 1.44 ± 1.46 for CAD, high-risk and healthy group, respectively. MP during handgrip stress was significantly lower for both the CAD (p = 0.0005) and high-risk groups (p = 0.05) compared to the healthy volunteers. In only the healthy subjects, MP was significantly higher in stress compared to rest (p = 0.0002). Participants with CAD had significantly lower MP response compared to healthy volunteers, as detected by ASL-CMR. These findings support the feasibility of ASL-CMR for non-invasive assessment of CED.
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Affiliation(s)
- Ahsan Javed
- Ming Hsieh Department of Electrical and computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Andrew Yoon
- Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Steven Cen
- Department of Neurology and Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Parveen Garg
- Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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15
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Do HP, Guo Y, Yoon AJ, Nayak KS. Accuracy, uncertainty, and adaptability of automatic myocardial ASL segmentation using deep CNN. Magn Reson Med 2019; 83:1863-1874. [PMID: 31729078 DOI: 10.1002/mrm.28043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/25/2023]
Abstract
PURPOSE To apply deep convolution neural network to the segmentation task in myocardial arterial spin labeled perfusion imaging and to develop methods that measure uncertainty and that adapt the convolution neural network model to a specific false-positive versus false-negative tradeoff. METHODS The Monte Carlo dropout U-Net was trained on data from 22 subjects and tested on data from 6 heart transplant recipients. Manual segmentation and regional myocardial blood flow were available for comparison. We consider 2 global uncertainty measures, named "Dice uncertainty" and "Monte Carlo dropout uncertainty," which were calculated with and without the use of manual segmentation, respectively. Tversky loss function with a hyperparameter β was used to adapt the model to a specific false-positive versus false-negative tradeoff. RESULTS The Monte Carlo dropout U-Net achieved a Dice coefficient of 0.91 ± 0.04 on the test set. Myocardial blood flow measured using automatic segmentations was highly correlated to that measured using the manual segmentation (R2 = 0.96). Dice uncertainty and Monte Carlo dropout uncertainty were in good agreement (R2 = 0.64). As β increased, the false-positive rate systematically decreased and false-negative rate systematically increased. CONCLUSION We demonstrate the feasibility of deep convolution neural network for automatic segmentation of myocardial arterial spin labeling, with good accuracy. We also introduce 2 simple methods for assessing model uncertainty. Finally, we demonstrate the ability to adapt the convolution neural network model to a specific false-positive versus false-negative tradeoff. These findings are directly relevant to automatic segmentation in quantitative cardiac MRI and are broadly applicable to automatic segmentation problems in diagnostic imaging.
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Affiliation(s)
- Hung P Do
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California
| | - Yi Guo
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California
| | - Andrew J Yoon
- Long Beach Memorial Medical Center, University of California Irvine, Irvine, California
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California
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Abstract
OBJECTIVES Multiparametric renal magnetic resonance imaging (MRI), including diffusion-weighted imaging, magnetic resonance elastography, and magnetization transfer imaging (MTI), is valuable in the noninvasive assessment of renal fibrosis. However, hemodynamic changes in diseased kidneys may impede their ability to measure renal fibrosis. Because MTI assesses directly tissue content of macromolecules, we test the hypothesis that MTI would be insensitive to renal hemodynamic changes in swine kidneys with acute graded ischemia. MATERIALS AND METHODS Seven domestic pigs underwent placement of an inflatable silicone cuff around the right renal artery to induce graded renal ischemia. Multiparametric MRI was performed at baseline, 50%, 75%, and 100% renal artery stenosis as well as reperfusion. Measurements included regional perfusion, R2*, apparent diffusion coefficient (ADC), stiffness, and magnetization transfer ratio (MTR) using arterial spin-labeled MRI, blood oxygenation-dependent MRI, diffusion-weighted imaging, magnetic resonance elastography, and MTI, respectively. Histology was performed to rule out renal fibrosis. RESULTS During graded ischemia, decreases in renal perfusion were accompanied with elevated R2*, decreased ADC, and stiffness, whereas no statistically significant changes were observed in the MTR. No fibrosis was detected by histology. After release of the obstruction, renal perfusion showed only partial recovery, associated with return of kidney R2*, ADC, and stiffness to baseline levels, whereas cortical MTR decreased slightly. CONCLUSIONS Renal MTI is insensitive to decreases in renal perfusion and may offer reliable assessment of renal structural changes.
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17
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Aramendía-Vidaurreta V, García-Osés A, Vidorreta M, Bastarrika G, Fernández-Seara MA. Optimal repetition time for free breathing myocardial arterial spin labeling. NMR IN BIOMEDICINE 2019; 32:e4077. [PMID: 30811728 DOI: 10.1002/nbm.4077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/21/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
The aim of this study was to improve the scan efficiency of ASL in the myocardium. Free breathing FAIR-ASL scans with different TRs were compared, while keeping the acquisition time constant. Scans were named by the trigger pulse that started each acquisition: every two (TP1), four (TP2) and six (TP3) cardiac cycles. TP2 offered the best alternative with a coefficient of variation of 17.15% intrasession and 36.85% intersession. Mean MBF increased by 0.22 ± 0.41 ml/g/min with mild stress.
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Affiliation(s)
| | | | | | - Gorka Bastarrika
- Radiology Department, Clínica Universidad de Navarra, Pamplona, Spain
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18
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Do HP, Ramanan V, Qi X, Barry J, Wright GA, Ghugre NR, Nayak KS. Non-contrast assessment of microvascular integrity using arterial spin labeled cardiovascular magnetic resonance in a porcine model of acute myocardial infarction. J Cardiovasc Magn Reson 2018; 20:45. [PMID: 29961424 PMCID: PMC6027570 DOI: 10.1186/s12968-018-0468-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 06/04/2018] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Following acute myocardial infarction (AMI), microvascular integrity and function may be compromised as a result of microvascular obstruction (MVO) and vasodilator dysfunction. It has been observed that both infarcted and remote myocardial territories may exhibit impaired myocardial blood flow (MBF) patterns associated with an abnormal vasodilator response. Arterial spin labeled (ASL) CMR is a novel non-contrast technique that can quantitatively measure MBF. This study investigates the feasibility of ASL-CMR to assess MVO and vasodilator response in swine. METHODS Thirty-one swine were included in this study. Resting ASL-CMR was performed on 24 healthy swine (baseline group). A subset of 13 swine from the baseline group underwent stress ASL-CMR to assess vasodilator response. Fifteen swine were subjected to a 90-min left anterior descending (LAD) coronary artery occlusion followed by reperfusion. Resting ASL-CMR was performed post-AMI at 1-2 days (N = 9, of which 6 were from the baseline group), 1-2 weeks (N = 8, of which 4 were from the day 1-2 group), and 4 weeks (N = 4, of which 2 were from the week 1-2 group). Resting first-pass CMR and late gadolinium enhancement (LGE) were performed post-AMI for reference. RESULTS At rest, regional MBF and physiological noise measured from ASL-CMR were 1.08 ± 0.62 and 0.15 ± 0.10 ml/g/min, respectively. Regional MBF increased to 1.47 ± 0.62 ml/g/min with dipyridamole vasodilation (P < 0.001). Significant reduction in MBF was found in the infarcted region 1-2 days, 1-2 weeks, and 4 weeks post-AMI compared to baseline (P < 0.03). This was consistent with perfusion deficit seen on first-pass CMR and with MVO seen on LGE. There were no significant differences between measured MBF in the remote regions pre and post-AMI (P > 0.60). CONCLUSIONS ASL-CMR can assess vasodilator response in healthy swine and detect significant reduction in regional MBF at rest following AMI. ASL-CMR is an alternative to gadolinium-based techniques for assessment of MVO and microvascular integrity within infarcted, as well as salvageable and remote myocardium. This has the potential to provide early indications of adverse remodeling processes post-ischemia.
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Affiliation(s)
- Hung P. Do
- Department of Physics and Astronomy, University of Southern California, 3740 McClintock Ave, EEB 400, Los Angeles, California 90089-2564 USA
| | - Venkat Ramanan
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON Canada
| | - Xiuling Qi
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON Canada
| | - Jennifer Barry
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON Canada
| | - Graham A. Wright
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
- Schulich Heart Research Program, Sunnybrook Health Sciences Centre, Toronto, ON Canada
| | - Nilesh R. Ghugre
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
- Schulich Heart Research Program, Sunnybrook Health Sciences Centre, Toronto, ON Canada
| | - Krishna S. Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA USA
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19
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Zun Z, Limperopoulos C. Placental perfusion imaging using velocity-selective arterial spin labeling. Magn Reson Med 2018; 80:1036-1047. [PMID: 29436733 DOI: 10.1002/mrm.27100] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/30/2017] [Accepted: 01/02/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Zungho Zun
- Division of Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC.,Division of Fetal and Transitional Medicine, Children's National Medical Center, Washington, DC.,Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC.,Department of Radiology, School of Medicine and Health Sciences, George Washington University, Washington, DC
| | - Catherine Limperopoulos
- Division of Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC.,Division of Fetal and Transitional Medicine, Children's National Medical Center, Washington, DC.,Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC.,Department of Radiology, School of Medicine and Health Sciences, George Washington University, Washington, DC
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20
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Chen HJ, Roy TL, Wright GA. Perfusion measures for symptom severity and differential outcome of revascularization in limb ischemia: Preliminary results with arterial spin labeling reactive hyperemia. J Magn Reson Imaging 2017; 47:1578-1588. [PMID: 29193492 DOI: 10.1002/jmri.25910] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/13/2017] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Previously, a theoretical model based on microvascular physiology was established to facilitate the interpretation of calf perfusion dynamics recorded by arterial spin labeling (ASL). PURPOSE To investigate the clinical relevance of novel perfusion indices by comparing them to the symptoms, response to revascularization, and short-term functional outcome in patients with peripheral arterial disease (PAD). STUDY TYPE Prospective cohort study. POPULATION Nineteen patients with PAD. FIELD STRENGTH/SEQUENCE Pulsed ASL at 3T. ASSESSMENT The mid-calf reactive hyperemia induced by 2 minutes of arterial occlusion was recorded in PAD patients. The perfusion responses were characterized by the peak, time-to-peak, and physiological model-derived indices including the baseline perfusion fr , arterial resistance Ra , and compliance Ca , and sensitivity gATP and response time τATP of downstream microvasculature to metabolic stress. These indices were compared to the disease severity and outcome within 6 months after revascularization assessed by self-reported symptoms and the ankle-brachial index. Disease severity was categorized as asymptomatic, claudication, or critical limb ischemia. The outcome was categorized as symptom resolved or limited improvement. STATISTICAL TESTS Severity and outcome groups were compared using Mann-Whitney and Kruskal-Wallis tests with Holm-Sidak adjustments. RESULTS The peak perfusion decreased and model arterial resistance increased progressively with increasing severity of limb ischemia (P = 0.0402 and 0.0413, respectively). Eleven patients had a successful endovascular procedure, including six patients who had symptoms resolved, four patients who had remaining leg pain, and one patient lost to follow-up. The subjects with limited improvement had significantly lower preintervention microvascular sensitivity gATP than those with symptoms resolved (8.72 ± 1.46 vs. 4.93 ± 0.91, P = 0.0466). DATA CONCLUSION ASL reactive hyperemia reflects multiple aspects of the pathophysiology. Measures of macrovascular arterial disease are related to the manifested symptom severity, whereas preintervention gATP associated with microvascular dysfunction is related to prognosis following revascularization. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:1578-1588.
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Affiliation(s)
- Hou-Jen Chen
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Schulich Heart Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Trisha L Roy
- Schulich Heart Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Division of Vascular Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Graham A Wright
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Schulich Heart Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
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21
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Jao TR, Nayak KS. Demonstration of velocity selective myocardial arterial spin labeling perfusion imaging in humans. Magn Reson Med 2017; 80:272-278. [PMID: 29106745 DOI: 10.1002/mrm.26994] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/19/2017] [Accepted: 10/13/2017] [Indexed: 12/30/2022]
Abstract
PURPOSE Transit delay is a potential source of error in cardiac arterial spin-labeled (ASL) in heart failure or with collateral circulation. This study demonstrates the feasibility of using transit delay insensitive velocity selective ASL and compares its performance with flow-sensitive alternating inversion recovery (FAIR) ASL. METHODS Velocity selective labeling was achieved using an adiabatic BIR8 preparation. FAIR and velocity-selective ASL (VSASL) with various velocity cutoffs (VC = 10-40 cm/s) and labeling directions (anterior-posterior X, lateral-septal Y, and apical-basal Z) were carried out in 10 healthy volunteers (1F/9M age 23-30 y). Myocardial blood flow (MBF) and temporal signal-to-noise (TSNR) were measured. RESULTS VSASL sensitivity to perfusion decreased with increasing VC . At low VC (<5 cm/s), spurious labeling of myocardium occurs and overestimates MBF. MBF measured with FAIR (1.12 ± 0.26 ml/g/min) and VASL (1.26 ± 0.27 ml/g/min) at VC of 10 cm/s in Z were comparable (TOST with difference of 0.30 ml/g/min, P = 0.049). TSNR was 2.8 times larger using FAIR (13.62 ± 5.25) than in VSASL (4.87 ± 1.58). VSASL was insensitive to perfusion in the Y direction. X and Z performed similarly with TSNR of 4.17 ± 2.32 and 3.97 ± 0.56, respectively. CONCLUSION VSASL is a promising alternative to FAIR ASL in the heart and is well suited for scenarios when transit delays are long. Magn Reson Med 80:272-278, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Terrence R Jao
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
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22
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Yoon AJ, Do HP, Cen S, Fong MW, Saremi F, Barr ML, Nayak KS. Assessment of segmental myocardial blood flow and myocardial perfusion reserve by adenosine-stress myocardial arterial spin labeling perfusion imaging. J Magn Reson Imaging 2017; 46:413-420. [DOI: 10.1002/jmri.25604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/05/2016] [Indexed: 01/19/2023] Open
Affiliation(s)
- Andrew J. Yoon
- Department of Medicine, Division of Cardiology, Keck School of Medicine of USC; University of Southern California; Los Angeles California USA
| | - Hung Phi Do
- Department of Physics and Astronomy; University of Southern California; Los Angeles California USA
| | - Steven Cen
- Department of Radiology, Keck School of Medicine of USC; University of Southern California; Los Angeles California USA
| | - Michael W. Fong
- Department of Medicine, Division of Cardiology, Keck School of Medicine of USC; University of Southern California; Los Angeles California USA
| | - Farhood Saremi
- Department of Radiology, Keck School of Medicine of USC; University of Southern California; Los Angeles California USA
| | - Mark L. Barr
- Department of Cardiothoracic Surgery, Keck School of Medicine of USC; University of Southern California; Los Angeles California USA
| | - Krishna S. Nayak
- Ming Hsieh Department of Electrical Engineering; University of Southern California; Los Angeles California USA
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23
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Zöllner FG, Gaa T, Zimmer F, Ong MM, Riffel P, Hausmann D, Schoenberg SO, Weis M. [Quantitative perfusion imaging in magnetic resonance imaging]. Radiologe 2016; 56:113-23. [PMID: 26796337 DOI: 10.1007/s00117-015-0068-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CLINICAL/METHODICAL ISSUE Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. STANDARD RADIOLOGICAL METHODS Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. PERFORMANCE Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. ACHIEVEMENTS The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. PRACTICAL RECOMMENDATIONS The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies.
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Affiliation(s)
- F G Zöllner
- Computerunterstützte Klinische Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland.
| | - T Gaa
- Computerunterstützte Klinische Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland
| | - F Zimmer
- Computerunterstützte Klinische Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland
| | - M M Ong
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - P Riffel
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - D Hausmann
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - S O Schoenberg
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - M Weis
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
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24
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Hosotani K, Ono A, Takeuchi K, Hashiguchi Y, Nagahata T. Flow visualization of simple pipe and channel flows obtained by MRI time-slip method. J Vis (Tokyo) 2016. [DOI: 10.1007/s12650-016-0395-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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25
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Keith GA, Rodgers CT, Chappell MA, Robson MD. A look-locker acquisition scheme for quantitative myocardial perfusion imaging with FAIR arterial spin labeling in humans at 3 tesla. Magn Reson Med 2016; 78:541-549. [PMID: 27604183 PMCID: PMC5516148 DOI: 10.1002/mrm.26388] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/28/2016] [Accepted: 07/28/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE A novel method for quantitative measurement of myocardial blood flow (MBF) using arterial spin labeling (ASL) in a single breath-hold is presented, evaluated by simulations, phantom studies and in vivo studies and tested for reproducibility and variability. METHODS A flow-sensitive alternating inversion recovery (FAIR) ASL method with Look-Locker readout (LL-FAIR-ASL) was implemented at 3 tesla. Scans were performed on 10 healthy volunteers and MBF measured in three slices. The method was investigated for reproducibility by Bland-Altman analysis and statistical measures, the coefficients of reproducibility (CR) and variation (CV) are reported. RESULTS The MBF values for the basal, mid, and apical slices were 1.04 ± 0.40, 1.06 ± 0.46, and 1.06 ± 0.38 ml/g/min, respectively (mean ± SD), which compare well with literature values. The CV across all scans, 43%, was greater than the between-session and within-session values, at 16 and 13%, respectively, for the mid-ventricular slice. The change in MBF required for detection, from the CR, was 61% between-session and 53% within-session for the mid-ventricle. CONCLUSION This study shows the feasibility of the LL-FAIR-ASL method for the quantification of MBF. The statistical measures reported will allow the planning of future clinical research studies involving rest and stress measurements. Magn Reson Med 78:541-549, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Graeme A. Keith
- Oxford Centre for Clinical Magnetic Resonance ResearchUniversity of Oxford, John Radcliffe HospitalOxfordUnited Kingdom
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance ResearchUniversity of Oxford, John Radcliffe HospitalOxfordUnited Kingdom
| | - Michael A. Chappell
- Institute of Biomedical EngineeringUniversity of Oxford, Old Road CampusOxfordUnited Kingdom
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance ResearchUniversity of Oxford, John Radcliffe HospitalOxfordUnited Kingdom
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26
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Hu HH, Li Z, Pokorney AL, Chia JM, Stefani N, Pipe JG, Miller JH. Assessment of cerebral blood perfusion reserve with acetazolamide using 3D spiral ASL MRI: Preliminary experience in pediatric patients. Magn Reson Imaging 2016; 35:132-140. [PMID: 27580517 DOI: 10.1016/j.mri.2016.08.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/03/2016] [Accepted: 08/20/2016] [Indexed: 01/04/2023]
Abstract
PURPOSE To demonstrate the clinical feasibility of a new non-Cartesian cylindrically-distributed spiral 3D pseudo-continuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI) pulse sequence in pediatric patients in quantifying cerebral blood flow (CBF) response to an acetazolamide (ACZ) vasodilator challenge. MATERIALS AND METHODS MRI exams were performed on two 3 Tesla Philips Ingenia systems using 32 channel head coil arrays. After local institutional review board approval, the 3D spiral-based pCASL technique was added to a standard brain MRI exam and evaluated in 13 pediatric patients (average age: 11.7±6.4years, range: 1.4-22.2years). All patients were administered ACZ for clinically indicated reasons. Quantitative whole-brain CBF measurements were computed pre- and post-ACZ to assess cerebrovascular reserve. RESULTS 3D spiral pCASL data were successfully reconstructed in all 13 cases. In 11 patients, CBF increased 2.8% to 93.2% after administration of ACZ. In the two remaining patients, CBF decreased by 2.4 to 6.0% after ACZ. The group average change in CBF due to ACZ was approximately 25.0% and individual changes were statistically significant (p<0.01) in all patients using a paired t-test analysis. CBF perfusion data were diagnostically useful in supporting conventional MR angiography and clinical findings. CONCLUSION 3D cylindrically-distributed spiral pCASL MRI provides a robust approach to assess cerebral blood flow and reserve in pediatric patients.
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Affiliation(s)
- Houchun H Hu
- Department of Medical Imaging and Radiology, Phoenix Children's Hospital, Phoenix, AZ, USA.
| | - Zhiqiang Li
- Keller Center for Imaging Innovation, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Amber L Pokorney
- Department of Medical Imaging and Radiology, Phoenix Children's Hospital, Phoenix, AZ, USA
| | | | | | - James G Pipe
- Keller Center for Imaging Innovation, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Jeffrey H Miller
- Department of Medical Imaging and Radiology, Phoenix Children's Hospital, Phoenix, AZ, USA
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Do HP, Yoon AJ, Fong MW, Saremi F, Barr ML, Nayak KS. Double‐gated myocardial ASL perfusion imaging is robust to heart rate variation. Magn Reson Med 2016; 77:1975-1980. [DOI: 10.1002/mrm.26282] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 04/27/2016] [Accepted: 05/01/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Hung Phi Do
- Department of Physics and AstronomyUniversity of Southern CaliforniaLos Angeles California USA
| | - Andrew J. Yoon
- Department of MedicineDivision of Cardiology, Keck School of Medicine of USC, University of Southern CaliforniaLos Angeles California USA
| | - Michael W. Fong
- Department of MedicineDivision of Cardiology, Keck School of Medicine of USC, University of Southern CaliforniaLos Angeles California USA
| | - Farhood Saremi
- Department of RadiologyKeck School of Medicine of USC, University of Southern CaliforniaLos Angeles California USA
| | - Mark L. Barr
- Department of Cardiothoracic SurgeryKeck School of Medicine of USC, University of Southern CaliforniaLos Angeles California USA
| | - Krishna S. Nayak
- Ming Hsieh Department of Electrical EngineeringUniversity of Southern CaliforniaLos Angeles California USA
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28
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Kober F, Jao T, Troalen T, Nayak KS. Myocardial arterial spin labeling. J Cardiovasc Magn Reson 2016; 18:22. [PMID: 27071861 PMCID: PMC4830031 DOI: 10.1186/s12968-016-0235-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/22/2016] [Indexed: 11/10/2022] Open
Abstract
Arterial spin labeling (ASL) is a cardiovascular magnetic resonance (CMR) technique for mapping regional myocardial blood flow. It does not require any contrast agents, is compatible with stress testing, and can be performed repeatedly or even continuously. ASL-CMR has been performed with great success in small-animals, but sensitivity to date has been poor in large animals and humans and remains an active area of research. This review paper summarizes the development of ASL-CMR techniques, current state-of-the-art imaging methods, the latest findings from pre-clinical and clinical studies, and future directions. We also explain how successful developments in brain ASL and small-animal ASL-CMR have helped to inform developments in large animal and human ASL-CMR.
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Affiliation(s)
- Frank Kober
- />Aix-Marseille Université, CNRS CRMBM UMR 7339, Centre de Résonance Magnétique Biologique et Médicale, Marseille, France
| | - Terrence Jao
- />Department of Biomedical Engineering, University of Southern California, Los Angeles, California USA
| | - Thomas Troalen
- />Aix-Marseille Université, CNRS CRMBM UMR 7339, Centre de Résonance Magnétique Biologique et Médicale, Marseille, France
| | - Krishna S. Nayak
- />Department of Biomedical Engineering, University of Southern California, Los Angeles, California USA
- />Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California USA
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29
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Fowkes LA, Koh DM, Collins DJ, Jerome NP, MacVicar D, Chua SC, Pearson ADJ. Childhood extracranial neoplasms: the role of imaging in drug development and clinical trials. Pediatr Radiol 2015; 45:1600-15. [PMID: 26045035 DOI: 10.1007/s00247-015-3342-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/16/2015] [Accepted: 03/16/2015] [Indexed: 12/25/2022]
Abstract
Cancer is the leading cause of death in children older than 1 year of age and new drugs are necessary to improve outcomes. Imaging is crucial to the drug development process and assessment of therapeutic response. In adults, tumours are often assessed with CT using size criteria. Unfortunately, techniques established in adults are not necessarily applicable in children due to differing pathophysiology, ability to cooperate and increased susceptibility to ionising radiation. MRI, in particular quantitative MRI, has to date not been fully utilised in children with extracranial neoplasms. The specific challenges of imaging in children, the potential for functional imaging techniques to inform upon and their inclusion in clinical trials are discussed.
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Affiliation(s)
- Lucy A Fowkes
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK.
| | - Dow-Mu Koh
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - David J Collins
- Cancer Research UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Road, Sutton, SM2 5NG, Surrey, UK
| | - Neil P Jerome
- Cancer Research UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Road, Sutton, SM2 5NG, Surrey, UK
| | - David MacVicar
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - Sue C Chua
- Nuclear Medicine & PET Department, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - Andrew D J Pearson
- Paediatric Drug Development Unit, Children and Young People's Unit, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
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30
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Sinclair MD, Lee J, Cookson AN, Rivolo S, Hyde ER, Smith NP. Measurement and modeling of coronary blood flow. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 7:335-56. [PMID: 26123867 DOI: 10.1002/wsbm.1309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 01/10/2023]
Abstract
Ischemic heart disease that comprises both coronary artery disease and microvascular disease is the single greatest cause of death globally. In this context, enhancing our understanding of the interaction of coronary structure and function is not only fundamental for advancing basic physiology but also crucial for identifying new targets for treating these diseases. A central challenge for understanding coronary blood flow is that coronary structure and function exhibit different behaviors across a range of spatial and temporal scales. While experimental studies have sought to understand this feature by isolating specific mechanisms, in tandem, computational modeling is increasingly also providing a unique framework to integrate mechanistic behaviors across different scales. In addition, clinical methods for assessing coronary disease severity are continuously being informed and updated by findings in basic physiology. Coupling these technologies, computational modeling of the coronary circulation is emerging as a bridge between the experimental and clinical domains, providing a framework to integrate imaging and measurements from multiple sources with mathematical descriptions of governing physical laws. State-of-the-art computational modeling is being used to combine mechanistic models with data to provide new insight into coronary physiology, optimization of medical technologies, and new applications to guide clinical practice.
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Affiliation(s)
- Matthew D Sinclair
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Andrew N Cookson
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Simone Rivolo
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Eoin R Hyde
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK.,Department of Engineering, University of Auckland, Auckland, New Zealand
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Park SH, Han PK, Choi SH. Physiological and Functional Magnetic Resonance Imaging Using Balanced Steady-state Free Precession. Korean J Radiol 2015; 16:550-9. [PMID: 25995684 PMCID: PMC4435985 DOI: 10.3348/kjr.2015.16.3.550] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 02/05/2015] [Indexed: 12/01/2022] Open
Abstract
Balanced steady-state free precession (bSSFP) is a highly efficient pulse sequence that is known to provide the highest signal-to-noise ratio per unit time. Recently, bSSFP is getting increasingly popular in both the research and clinical communities. This review will be focusing on the application of the bSSFP technique in the context of probing the physiological and functional information. In the first part of this review, the basic principles of bSSFP are briefly covered. Afterwards, recent developments related to the application of bSSFP, in terms of physiological and functional imaging, are introduced and reviewed. Despite its long development history, bSSFP is still a promising technique that has many potential benefits for obtaining high-resolution physiological and functional images.
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Affiliation(s)
- Sung-Hong Park
- Magnetic Resonance Imaging Lab, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Paul Kyu Han
- Magnetic Resonance Imaging Lab, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Seung Hong Choi
- Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea
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Miyazaki M, Zhou X, Hoshino T, Yokoyama K, Ishimura R, Nitatori T. Non-contrast myocardial perfusion using a novel 4D magnetic resonance arterial spin labeling technique: Initial experience. Microvasc Res 2015; 98:94-101. [DOI: 10.1016/j.mvr.2015.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 12/17/2014] [Accepted: 01/21/2015] [Indexed: 11/25/2022]
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Motwani M, Kidambi A, Uddin A, Sourbron S, Greenwood JP, Plein S. Quantification of myocardial blood flow with cardiovascular magnetic resonance throughout the cardiac cycle. J Cardiovasc Magn Reson 2015; 17:4. [PMID: 25630861 PMCID: PMC4308908 DOI: 10.1186/s12968-015-0107-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 12/31/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Myocardial blood flow (MBF) varies throughout the cardiac cycle in response to phasic changes in myocardial tension. The aim of this study was to determine if quantitative myocardial perfusion imaging with cardiovascular magnetic resonance (CMR) can accurately track physiological variations in MBF throughout the cardiac cycle. METHODS 30 healthy volunteers underwent a single stress/rest perfusion CMR study with data acquisition at 5 different time points in the cardiac cycle (early-systole, mid-systole, end-systole, early-diastole and end-diastole). MBF was estimated on a per-subject basis by Fermi-constrained deconvolution. Interval variations in MBF between successive time points were expressed as percentage change. Maximal cyclic variation (MCV) was calculated as the percentage difference between maximum and minimum MBF values in a cardiac cycle. RESULTS At stress, there was significant variation in MBF across the cardiac cycle with successive reductions in MBF from end-diastole to early-, mid- and end-systole, and an increase from early- to end-diastole (end-diastole: 4.50 ± 0.91 vs. early-systole: 4.03 ± 0.76 vs. mid-systole: 3.68 ± 0.67 vs. end-systole 3.31 ± 0.70 vs. early-diastole: 4.11 ± 0.83 ml/g/min; all p values <0.0001). In all cases, the maximum and minimum stress MBF values occurred at end-diastole and end-systole respectively (mean MCV = 26 ± 5%). There was a strong negative correlation between MCV and peak heart rate at stress (r = -0.88, p < 0.001). The largest interval variation in stress MBF occurred between end-systole and early-diastole (24 ± 9% increase). At rest, there was no significant cyclic variation in MBF (end-diastole: 1.24 ± 0.19 vs. early-systole: 1.28 ± 0.17 vs.mid-systole: 1.28 ± 0.17 vs. end-systole: 1.27 ± 0.19 vs. early-diastole: 1.29 ± 0.19 ml/g/min; p = 0.71). CONCLUSION Quantitative perfusion CMR can be used to non-invasively assess cyclic variations in MBF throughout the cardiac cycle. In this study, estimates of stress MBF followed the expected physiological trend, peaking at end-diastole and falling steadily through to end-systole. This technique may be useful in future pathophysiological studies of coronary blood flow and microvascular function.
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Affiliation(s)
- Manish Motwani
- />Leeds Institute of Cardiovascular and Metabolic Medicine, Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Ananth Kidambi
- />Leeds Institute of Cardiovascular and Metabolic Medicine, Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Akhlaque Uddin
- />Leeds Institute of Cardiovascular and Metabolic Medicine, Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Steven Sourbron
- />Division of Medical Physics, University of Leeds, Leeds, UK
| | - John P Greenwood
- />Leeds Institute of Cardiovascular and Metabolic Medicine, Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Sven Plein
- />Leeds Institute of Cardiovascular and Metabolic Medicine, Division of Biomedical Imaging, University of Leeds, Leeds, UK
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Capron T, Troalen T, Robert B, Jacquier A, Bernard M, Kober F. Myocardial perfusion assessment in humans using steady-pulsed arterial spin labeling. Magn Reson Med 2014; 74:990-8. [DOI: 10.1002/mrm.25479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/04/2014] [Accepted: 09/07/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Thibaut Capron
- Aix-Marseille Université, UMR 7339, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale); 13385 Marseille France
| | - Thomas Troalen
- Aix-Marseille Université, UMR 7339, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale); 13385 Marseille France
| | | | - Alexis Jacquier
- Aix-Marseille Université, UMR 7339, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale); 13385 Marseille France
| | - Monique Bernard
- Aix-Marseille Université, UMR 7339, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale); 13385 Marseille France
| | - Frank Kober
- Aix-Marseille Université, UMR 7339, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale); 13385 Marseille France
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Do HP, Jao TR, Nayak KS. Myocardial arterial spin labeling perfusion imaging with improved sensitivity. J Cardiovasc Magn Reson 2014; 16:15. [PMID: 24467918 PMCID: PMC3913326 DOI: 10.1186/1532-429x-16-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Myocardial arterial spin labeling (ASL) is a noninvasive MRI based technique that is capable of measuring myocardial blood flow (MBF) in humans. It suffers from poor sensitivity to MBF due to high physiological noise (PN). This study aims to determine if the sensitivity of myocardial ASL to MBF can be improved by reducing image acquisition time, via parallel imaging. METHODS Myocardial ASL scans were performed in 7 healthy subjects at rest using flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady state free precession (SSFP) imaging. Sensitivity encoding (SENSE) with a reduction factor of 2 was used to shorten each image acquisition from roughly 300 ms per heartbeat to roughly 150 ms per heartbeat. A paired Student's t-test was performed to compare measurements of myocardial blood flow (MBF) and physiological noise (PN) from the reference and accelerated methods. RESULTS The measured PN (mean ± standard deviation) was 0.20 ± 0.08 ml/g/min for the reference method and 0.08 ± 0.05 ml/g/min for the accelerated method, corresponding to a 60% reduction. PN measured from the accelerated method was found to be significantly lower than that of the reference method (p=0.0059). There was no significant difference between MBF measured from the accelerated and reference ASL methods (p=0.7297). CONCLUSIONS In this study, significant PN reduction was achieved by shortening the acquisition window using parallel imaging with no significant impact on the measured MBF. This indicates an improvement in sensitivity to MBF and may also enable the imaging of subjects with higher heart rates and imaging during systole.
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Affiliation(s)
- Hung Phi Do
- Department of Physics and Astronomy, University of Southern California, 3740 McClintock Ave, EEB 400, Los Angeles, CA 90089-2564, USA
| | - Terrence R Jao
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA
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Pharmacologic manipulation of coronary vascular physiology for the evaluation of coronary artery disease. Pharmacol Ther 2013; 140:121-32. [DOI: 10.1016/j.pharmthera.2013.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 11/24/2022]
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Zhang H, Ye Q, Zheng J, Schelbert EB, Hitchens TK, Ho C. Improve myocardial T1 measurement in rats with a new regression model: application to myocardial infarction and beyond. Magn Reson Med 2013; 72:737-48. [PMID: 24142881 DOI: 10.1002/mrm.24988] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 08/13/2013] [Accepted: 09/15/2013] [Indexed: 11/09/2022]
Abstract
PURPOSE To improve myocardial and blood T1 measurements with a multi-variable T1 fitting model specifically modified for a segmented multi-shot FLASH sequence. METHODS The proposed method was first evaluated in a series of phantoms simulating realistic tissues, and then in healthy rats (n = 8) and rats with acute myocardial infarction (MI) induced by coronary artery ligation (n = 8). RESULTS By taking into account the saturation effect caused by sampling α-train pulses, and the longitudinal magnetization recovery between readouts, our model provided more accurate T1 estimate than the conventional three-parameter fit in phantoms under realistic gating procedures (error of -0.42 ± 1.73% versus -3.40 ± 1.46%, respectively, when using the measured inversion efficiency, β). The baseline myocardial T1 values in healthy rats was 1636.3 ± 23.4 ms at 7 Tesla. One day postligation, the T1 values in the remote and proximal myocardial areas were 1637.5 ± 62.6 ms and 1740.3 ± 70.5 ms, respectively. In rats with acute MI, regional differences in myocardial T1 values were observed both before and after the administration of gadolinium. CONCLUSION The proposed method has improved T1 estimate as validated in phantoms and could advance applications in rodents using quantitative myocardial T1 mapping.
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Affiliation(s)
- Haosen Zhang
- Pittsburgh NMR Center for Biomedical Research, Department of Biological Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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Bratis K, Mahmoud I, Chiribiri A, Nagel E. Quantitative myocardial perfusion imaging by cardiovascular magnetic resonance and positron emission tomography. J Nucl Cardiol 2013; 20:860-70; quiz 857-9, 871-3. [PMID: 23868071 PMCID: PMC7611156 DOI: 10.1007/s12350-013-9762-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 07/01/2013] [Indexed: 12/19/2022]
Abstract
Recent studies have demonstrated that a detailed knowledge of the extent of angiographic coronary artery disease (CAD) is not a prerequisite for clinical decision making, and the clinical management of patients with CAD is more and more focused towards the identification of myocardial ischemia and the quantification of ischemic burden. In this view, non-invasive assessment of ischemia and in particular stress imaging techniques are emerging as preferred and non-invasive options. A quantitative assessment of regional myocardial perfusion can provide an objective estimate of the severity of myocardial injury and may help clinicians to discriminate regions of the heart that are at increased risk for myocardial infarction. Positron emission tomography (PET) has established itself as the reference standard for myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) quantification. Cardiac magnetic resonance (CMR) is increasingly used to measure MBF and MPR by means of first-pass signals, with a well-defined diagnostic performance and prognostic value. The aim of this article is to review the currently available evidence on the use of both PET and CMR for quantification of MPR, with particular attention to the studies that directly compared these two diagnostic methods.
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Affiliation(s)
- K Bratis
- Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom,
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MRI for the assessment of organ perfusion in patients with chronic kidney disease. Curr Opin Nephrol Hypertens 2013; 21:647-54. [PMID: 23010761 DOI: 10.1097/mnh.0b013e328358d582] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Recent data have highlighted the importance of quantitative measures of organ perfusion and functional reserve. Magnetic resonance imaging allows the assessment of markers of perfusion without the use of contrast media. Techniques such as arterial spin labelling (ASL) and blood oxygen level-dependent (BOLD) imaging have been available for some time, but advances in the technology and concerns over the safety of contrast media in renal disease have spurred renewed interest and development. RECENT FINDINGS ASL measures perfusion, whereas BOLD imaging provides a marker of blood oxygenation, arising from the compound effect of a number of measures including perfusion, blood volume and oxygen consumption; thus, the techniques are complementary rather than analogous. They were initially confined to brain imaging as inherently low signal, susceptibility effects and motion limited their use in thoracic and abdominal organs. Advances in technology have led to robust sequences that can quantify clinically relevant changes and correlate well with reference standards. Novel approaches are likely to accelerate translation into clinical practice. SUMMARY The noninvasive and repeatable nature of ASL and BOLD imaging makes it likely that they will be increasingly used in clinical research. Using a developmental framework, we suggest that the application of these techniques to thoracic and abdominal organs requires validation before they are suitable for generalized clinical use. The demand for these techniques is likely to be driven by the incentive to avoid the use of contrast media.
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Li X, Metzger GJ. Feasibility of measuring prostate perfusion with arterial spin labeling. NMR IN BIOMEDICINE 2013; 26:51-7. [PMID: 22674425 PMCID: PMC3455122 DOI: 10.1002/nbm.2818] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 04/05/2012] [Accepted: 04/18/2012] [Indexed: 05/09/2023]
Abstract
Prostate perfusion has the potential to become an important pathophysiological marker for the monitoring of disease progression or the assessment of the therapeutic response of prostate cancer. The feasibility of arterial spin labeling, an MRI approach for the measurement of perfusion without an exogenous contrast agent, is demonstrated in the prostate for the first time. Although various arterial spin labeling methods have been demonstrated previously in highly perfused organs, such as the brain and kidneys, the prospect of obtaining such measurements in the prostate is challenging because of the relatively low blood flow, long transit times, susceptibility-induced image distortion and local motion. However, despite these challenges, this study demonstrates that, with a whole-body transmit coil and external receiver array, global prostate perfusion can be measured with arterial spin labeling at 3 T. In five healthy subjects with a mean age of 44 years, the mean total prostate blood flow was measured to be 25.8 ± 7.1 mL/100 cm(3) /min, with an estimated bolus duration and arterial transit time of 884 ± 209 ms and 721 ± 131 ms, respectively.
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Affiliation(s)
- Xiufeng Li
- Center for Magnetic Resonance Research, Radiology, University of Minnesota, Minneapolis, MN 55455, USA
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Capron T, Troalen T, Cozzone PJ, Bernard M, Kober F. Cine-ASL: a steady-pulsed arterial spin labeling method for myocardial perfusion mapping in mice. Part II. Theoretical model and sensitivity optimization. Magn Reson Med 2012; 70:1399-408. [PMID: 23281063 DOI: 10.1002/mrm.24588] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/17/2012] [Accepted: 11/14/2012] [Indexed: 12/21/2022]
Abstract
In small rodent myocardial perfusion studies, the most widely used method is based on Look-Locker measurements of the magnetization recovery after FAIR preparation, which bears limitations regarding acquisition efficiency due to the pulsed arterial spin labeling nature of the sequence. To improve efficiency, this two-article set proposes a new steady-pulsed arterial spin labeling scheme using a cine readout incorporating one tagging pulse per heart cycle. In this part, we derive a theoretical description of the magnetization time evolution in such a scheme. The combination of steady-pulsed labeling and cine readout drives tissue magnetization into a stationary regime that explicitly depends on perfusion. In comparison with dedicated experiments on the mouse heart, the model is discussed and validated for perfusion quantification. The model predicts that in this regime, signal is independent of irregular dynamics occurring during acquisition, such as heart rate variations or arterial input function. Optimization of the sequence offers the possibility to increase the signal to noise ratio by efficient signal averaging. The sensitivity of this new method is shown to be more than three times larger than previously used techniques.
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Affiliation(s)
- Thibaut Capron
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS N°7339, Faculté de Médecine, Aix-Marseille Université, Marseille, France
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Abeykoon S, Sargent M, Wansapura JP. Quantitative myocardial perfusion in mice based on the signal intensity of flow sensitized CMR. J Cardiovasc Magn Reson 2012; 14:73. [PMID: 23095212 PMCID: PMC3519741 DOI: 10.1186/1532-429x-14-73] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 10/11/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND In the conventional approach to arterial spin labeling in the rodent heart, the relative difference in the apparent T(1) relaxation times corresponding to selective and non-selective inversion is related to perfusion via a two compartment model of tissue. But accurate determination of T(1) in small animal hearts is difficult and prone to errors due to long scan times and high heart rates. In this study we introduce the theoretical frame work for an alternative method (SI-method) based purely on the signal intensity of slice-select and non-select inversion recovery images at a single inversion time at short repetition time. METHODS A modified Bloch equation was solved to derive perfusion as a function of signal intensity of flow sensitized segmented gradient echo acquisitions. A two compartment fast exchanging model of tissue was assumed. To test the new technique first it was implemented on a flow phantom and then it was compared with the conventional T(1) method in an in vivo study of healthy C57BL/6 mice (n=12). Finally the SI-method was used in comparison to a Late Gadolinium Enhanced (LGE) method to qualitatively and quantitatively assess perfusion deficits in an ischemia-reperfusion mouse model (n=4). RESULTS The myocardial perfusion of healthy mice obtained by the SI-method, 5.6 ± 0.5 ml/g/min, (mean ± standard deviation) was similar (p=0.38) to that obtained by the conventional method, 5.6 ± 0.3 ml/g/min. The variance in perfusion within the left ventricle was less for the SI-method than that for the conventional method (p<0.0001). The mean percentage standard deviation among repeated measures was 3.6%. The LGE regions of the ischemia reperfusion model were matched with regions of hypo-perfusion in the perfusion map. The average perfusion in the hypo perfused region among all four IR mice was 1.2 ± 0.9 ml/g/min and that of the remote region was 4.4 ± 1.2 ml/g/min. CONCLUSIONS The proposed signal intensity based ASL method with a segmented acquisition scheme allows accurate high resolution perfusion mapping in small animals. It's short scan time, high reproducibility and ease of post process makes it a robust alternative to the conventional ASL technique that relies on T(1) measurements.
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Affiliation(s)
- Sumeda Abeykoon
- Department of Physics, University of Cincinnati, Cincinnati, OH, USA
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital, 3333 Burnet Ave, MLC 5033, Cincinnati, OH, 45229, USA
| | - Michelle Sargent
- Howard Hughes Medical Institute, Molecular Cardiovascular Biology, Cincinnati Children Hospital, Cincinnati, OH, USA
| | - Janaka P Wansapura
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital, 3333 Burnet Ave, MLC 5033, Cincinnati, OH, 45229, USA
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Zun Z, Varadarajan P, Pai RG, Wong EC, Nayak KS. Arterial spin labeled CMR detects clinically relevant increase in myocardial blood flow with vasodilation. JACC Cardiovasc Imaging 2012; 4:1253-61. [PMID: 22172781 DOI: 10.1016/j.jcmg.2011.06.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 11/20/2022]
Abstract
OBJECTIVES This study sought to determine whether arterial spin labeled (ASL) cardiac magnetic resonance (CMR) is capable of detecting clinically relevant increases in regional myocardial blood flow (MBF) with vasodilator stress testing in human myocardium. BACKGROUND Measurements of regional myocardial perfusion at rest and during vasodilatation are used to determine perfusion reserve, which indicates the presence and distribution of myocardial ischemia. ASL CMR is a perfusion imaging technique that does not require any contrast agents, and is therefore safe for use in patients with end-stage renal disease, and capable of repeated or continuous measurement. METHODS Myocardial ASL scans at rest and during adenosine infusion were incorporated into a routine CMR adenosine induced vasodilator stress protocol and was performed in 29 patients. Patients who were suspected of having ischemic heart disease based on first-pass imaging also underwent x-ray angiography. Myocardial ASL was performed using double-gated flow-sensitive alternating inversion recovery tagging and balanced steady-state free precession imaging at 3-T. RESULTS Sixteen patients were found to be normal and 13 patients were found to have visible perfusion defect based on first-pass CMR using intravenous gadolinium chelate. In the normal subjects, there was a statistically significant difference between MBF measured by ASL during adenosine infusion (3.67 ± 1.36 ml/g/min), compared to at rest (0.97 ± 0.64 ml/g/min), with p < 0.0001. There was also a statistically significant difference in perfusion reserve (MBF(stress)/MBF(rest)) between normal myocardial segments (3.18 ± 1.54) and the most ischemic segments in the patients with coronary artery disease identified by x-ray angiography (1.44 ± 0.97), with p = 0.0011. CONCLUSIONS This study indicates that myocardial ASL is capable of detecting clinically relevant increases in MBF with vasodilatation and has the potential to identify myocardial ischemia.
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Affiliation(s)
- Zungho Zun
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA
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Epstein FH, Meyer CH. Myocardial perfusion using arterial spin labeling CMR: promise and challenges. JACC Cardiovasc Imaging 2012; 4:1262-4. [PMID: 22172782 DOI: 10.1016/j.jcmg.2011.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 08/22/2011] [Indexed: 11/25/2022]
Affiliation(s)
- Frederick H Epstein
- Department of Biomedical Engineering and the Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22908, USA
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Animal Models in Cardiovascular MRI Research: Value and Limitations. CURRENT CARDIOVASCULAR IMAGING REPORTS 2012. [DOI: 10.1007/s12410-012-9128-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Quantification of Myocardial Perfusion: MRI. CURRENT CARDIOVASCULAR IMAGING REPORTS 2012. [DOI: 10.1007/s12410-012-9135-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Noninvasive or minimally invasive imaging techniques are essential for developing strategies and assessing outcomes of cell-based therapies for myocardial regeneration, also referred to as cellular cardiomyoplasty. Imaging-based monitoring of cell survival is useful for selection of optimal cell type and evaluating strategies to enhance engraftment. Imaging-derived surrogate end points including global and regional contractile function, myocardial blood flow, or perfusion and bioenergetics have been used in clinical trials or in relevant large animal models to evaluate the therapeutic effect and mechanisms of action of cellular cardiomyoplasty. New techniques are emerging to assess electrical integration of donor cells with host cardiomyocytes. This review will summarize and highlight important and informative findings revealed by imaging in clinical and preclinical cellular cardiomyoplasty studies over the past 3 years.
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Goergen CJ, Sosnovik DE. From molecules to myofibers: multiscale imaging of the myocardium. J Cardiovasc Transl Res 2011; 4:493-503. [PMID: 21643889 DOI: 10.1007/s12265-011-9284-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 04/26/2011] [Indexed: 01/14/2023]
Abstract
Pathology in the heart can be examined at several scales, ranging from the molecular to the macroscopic. Traditionally, fluorescence-based techniques such as flow cytometry have been used to study the myocardium at the molecular, cellular, and microscopic levels. Recent advances in magnetic resonance imaging (MRI), however, have made it possible to image certain cellular and molecular events in the myocardium noninvasively in vivo. In addition, diffusion MRI has been used to image myocardial fiber architecture and microstructure in the intact heart. Diffusion MRI tractography, in particular, is providing novel insights into myocardial microsctructure in both health and disease. Recent developments have also been made in fluorescence imaging, making it possible to image fluorescent probes in the heart of small animals noninvasively in vivo. Moreover, techniques have been developed to perform in vivo fluorescence tomography of the mouse heart. These advances in MRI and fluorescence imaging allow events in the myocardium to be imaged at several scales linking molecular changes to alterations in microstructure and microstructural changes to gross function. A complete and integrated picture of pathophysiology in the myocardium is thus obtained. This multiscale approach has the potential to be of significant value not only in preclinical research but, ultimately, in the clinical arena as well.
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Affiliation(s)
- Craig J Goergen
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Vandsburger MH, Epstein FH. Emerging MRI methods in translational cardiovascular research. J Cardiovasc Transl Res 2011; 4:477-92. [PMID: 21452060 DOI: 10.1007/s12265-011-9275-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 03/15/2011] [Indexed: 12/11/2022]
Abstract
Cardiac magnetic resonance imaging (CMR) has become a reference standard modality for imaging of left ventricular (LV) structure and function and, using late gadolinium enhancement, for imaging myocardial infarction. Emerging CMR techniques enable a more comprehensive examination of the heart, making CMR an excellent tool for use in translational cardiovascular research. Specifically, emerging CMR methods have been developed to measure the extent of myocardial edema, changes in ventricular mechanics, changes in tissue composition as a result of fibrosis, and changes in myocardial perfusion as a function of both disease and infarct healing. New CMR techniques also enable the tracking of labeled cells, molecular imaging of biomarkers of disease, and changes in calcium flux in cardiomyocytes. In addition, MRI can quantify blood flow velocity and wall shear stress in large blood vessels. Almost all of these techniques can be applied in both pre-clinical and clinical settings, enabling both the techniques themselves and the knowledge gained using such techniques in pre-clinical research to be translated from the lab bench to the patient bedside.
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Affiliation(s)
- Moriel H Vandsburger
- Department of Biological Regulation, Weizmann Institute of Science, 76100, Rehovot, Israel.
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