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Taylor EN, Huang N, Lin S, Mortazavi F, Wedeen VJ, Siamwala JH, Gilbert RJ, Hamilton JA. Lipid and smooth muscle architectural pathology in the rabbit atherosclerotic vessel wall using Q-space cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2022; 24:74. [PMID: 36544161 PMCID: PMC9773609 DOI: 10.1186/s12968-022-00897-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Atherosclerosis is an arterial vessel wall disease characterized by slow, progressive lipid accumulation, smooth muscle disorganization, and inflammatory infiltration. Atherosclerosis often remains subclinical until extensive inflammatory injury promotes vulnerability of the atherosclerotic plaque to rupture with luminal thrombosis, which can cause the acute event of myocardial infarction or stroke. Current bioimaging techniques are unable to capture the pathognomonic distribution of cellular elements of the plaque and thus cannot accurately define its structural disorganization. METHODS We applied cardiovascular magnetic resonance spectroscopy (CMRS) and diffusion weighted CMR (DWI) with generalized Q-space imaging (GQI) analysis to architecturally define features of atheroma and correlated these to the microscopic distribution of vascular smooth muscle cells (SMC), immune cells, extracellular matrix (ECM) fibers, thrombus, and cholesteryl esters (CE). We compared rabbits with normal chow diet and cholesterol-fed rabbits with endothelial balloon injury, which accelerates atherosclerosis and produces advanced rupture-prone plaques, in a well-validated rabbit model of human atherosclerosis. RESULTS Our methods revealed new structural properties of advanced atherosclerosis incorporating SMC and lipid distributions. GQI with tractography portrayed the locations of these components across the atherosclerotic vessel wall and differentiated multi-level organization of normal, pro-inflammatory cellular phenotypes, or thrombus. Moreover, the locations of CE were differentiated from cellular constituents by their higher restrictive diffusion properties, which permitted chemical confirmation of CE by high field voxel-guided CMRS. CONCLUSIONS GQI with tractography is a new method for atherosclerosis imaging that defines a pathological architectural signature for the atheromatous plaque composed of distributed SMC, ECM, inflammatory cells, and thrombus and lipid. This provides a detailed transmural map of normal and inflamed vessel walls in the setting of atherosclerosis that has not been previously achieved using traditional CMR techniques. Although this is an ex-vivo study, detection of micro and mesoscale level vascular destabilization as enabled by GQI with tractography could increase the accuracy of diagnosis and assessment of treatment outcomes in individuals with atherosclerosis.
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Affiliation(s)
- Erik N Taylor
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
- Department of Radiology, UNM School of Medicine, The University of New Mexico, Albuquerque, NM, USA
| | - Nasi Huang
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Sunni Lin
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Farzad Mortazavi
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Van J Wedeen
- AA Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jamila H Siamwala
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center and Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - James A Hamilton
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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Su Y, Peng Q, Yin L, Li C. Evaluation of Exercise Tolerance in Non-obstructive Hypertrophic Cardiomyopathy With Myocardial Work and Peak Strain Dispersion by Speckle-Tracking Echocardiography. Front Cardiovasc Med 2022; 9:927671. [PMID: 35958415 PMCID: PMC9361015 DOI: 10.3389/fcvm.2022.927671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe aim of this study was to evaluate exercise tolerance in non-obstructive hypertrophic cardiomyopathy (HCM) by investigating the value of myocardial work (MW) combined with strain peak dispersion.MethodsA total of 65 patients with non-obstructive HCM and normal left ventricular ejection fraction were enrolled and 60 healthy subjects were selected as controls. The automated function imaging (AFI)-two-dimensional ultrasonic speckle-tracking technology was used to obtain the values for peak global longitudinal strain (GLS), longitudinal strain peak time dispersion (PSD), 18-segment systolic longitudinal peak strain (LPS), 18-segment longitudinal strain peak time (TTPLS), global waste work (GWW), global constructive work (GCW), global work index (GWI), global work efficiency (GWE), and exercise metabolic equivalents (METS).Results(1) Values for LV-GLS (−17.77 ± 0.20 vs. −21.66 ± 0.42%) were lower and PSD (95.10 ± 8.15 vs. 28.97 ± 1.50 ms) was prolonged in patients with HCM (p < 0.01). (2) An increasing trend was shown in the basal segment < intermediate segment < apical segment for both patients with HCM and controls, although each segment had lower values in the HCM group. (3) TTPLS was prolonged in the HCM group (p < 0.01). (4) GWE, GWI, and GCW were all lower (p < 0.01) and GWW was higher in patients with HCM (p < 0.01). (5) Values of GWE were less than 92.5%, GWI less than 1,200 mmHg, GCW less than 1,399 mmHg, these abnormal values are helpful for the diagnosis of impaired exercise tolerance and poor prognosis (6) The METS and LV-GLS of HCM in the asymmetric group were significantly lower than that in AHCM group, but the PSD was significantly greater than that in the AHCM group. Values of LPS-BL (−13.13% ± 2.51% vs −10.17% ± 2.20%) in the apical HCM group were better than in the asymmetric HCM group (p < 0.05).ConclusionGCW, GWI, and GWE can be safely measured by resting echocardiography to evaluate exercise tolerance in patients with HCM who cannot perform an exercise-based examination. Such measurements provide a basis for clinical decisions regarding exercise and drug prescription.
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Affiliation(s)
- Ye Su
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Department of Cardiovascular Ultrasound, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Qionghui Peng
- Department of Cardiovascular Ultrasound, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Lixue Yin
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Department of Cardiovascular Ultrasound, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
- *Correspondence: Lixue Yin, ;
| | - Chunmei Li
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Department of Cardiovascular Ultrasound, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
- Chunmei Li,
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Lv Q, Li M, Li H, Wu C, Dong N, Li Y, Zhang L, Xie M. Assessment of biventricular function by three-dimensional speckle-tracking echocardiography in clinically well pediatric heart transplantation patients. Echocardiography 2020; 37:2107-2115. [PMID: 33078446 DOI: 10.1111/echo.14893] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/08/2020] [Accepted: 09/25/2020] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The biventricular function plays an important role in the prognosis of pediatric heart transplantation (HTx) patients. Therefore, in this study, we aimed to evaluate the biventricular function of pediatric HTx patients by three-dimensional (3D) speckle-tracking echocardiography (3D-STE). METHODS We enrolled 30 clinically well pediatric HTx patients and 30 healthy controls with a similar distribution of sex and age to the HTx. All participants underwent comprehensive two-dimensional (2D) and 3D echocardiography. Left ventricular (LV) global longitudinal strain (GLS), global circumferential strain (GCS), left and right ventricular ejection fraction (LVEF and RVEF, respectively), and right ventricular free wall longitudinal strain (RV FWLS) were acquired by 3D-STE. Moreover, the correlations between strains and clinical data were explored. RESULTS Compared with controls, LV GLS was decreased in pediatric HTx patients (P < .05), while LV GCS and LVEF showed no difference. LV GLS showed a weak correlation with cold ischemic time in HTx group (r = 0.396, P < .05). Meanwhile, RVEF and RV FWLS were significantly lower in the HTx group (P < .05). In the HTx group, RV FWLS showed a weak correlation with the preoperative mean pulmonary artery pressure (r = 0.420, P < .05) and postoperative pulmonary artery systolic pressure (r = 0.465, P < .05). CONCLUSION The 3D-biventricular mechanical functions were decreased in clinically well pediatric HTx patients. The provided characteristics and appropriate normal values of biventricular mechanical functions can be the basis in subsequent studies in the pediatric HTx patients.
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Affiliation(s)
- Qing Lv
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Meng Li
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - He Li
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Chun Wu
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Nianguo Dong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuman Li
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Li Zhang
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
| | - Mingxing Xie
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
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Campanale CM, Scherrer B, Afacan O, Majeed A, Warfield SK, Sanders SP. Myofiber organization in the failing systemic right ventricle. J Cardiovasc Magn Reson 2020; 22:49. [PMID: 32600420 PMCID: PMC7322876 DOI: 10.1186/s12968-020-00637-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 05/13/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The right ventricle (RV) often fails when functioning as the systemic ventricle, but the cause is not understood. We tested the hypothesis that myofiber organization is abnormal in the failing systemic right ventricle. METHODS We used diffusion-weighted cardiovascular magnetic resonance imaging to examine 3 failing hearts explanted from young patients with a systemic RV and one structurally normal heart with postnatally acquired RV hypertrophy for comparison. Diffusion compartment imaging was computed to separate the free diffusive component representing free water from an anisotropic component characterizing the orientation and diffusion characteristics of myofibers. The orientation of each anisotropic compartment was displayed in glyph format and used for qualitative description of myofibers and for construction of tractograms. The helix angle was calculated across the ventricular walls in 5 locations and displayed graphically. Scalar parameters (fractional anisotropy and mean diffusivity) were compared among specimens. RESULTS The hypertrophied systemic RV has an inner layer, comprising about 2/3 of the wall, composed of hypertrophied trabeculae and an epicardial layer of circumferential myofibers. Myofibers within smaller trabeculae are aligned and organized with parallel fibers while larger, composite bundles show marked disarray, largely between component trabeculae. We observed a narrow range of helix angles in the outer, compact part of the wall consistent with aligned, approximately circumferential fibers. However, there was marked variation of helix angle in the inner, trabecular part of the wall consistent with marked variation in fiber orientation. The apical whorl was disrupted or incomplete and we observed myocardial whorls or vortices at other locations. Fractional anisotropy was lower in abnormal hearts while mean diffusivity was more variable, being higher in 2 but lower in 1 heart, compared to the structurally normal heart. CONCLUSIONS Myofiber organization is abnormal in the failing systemic RV and might be an important substrate for heart failure and arrhythmia. It is unclear if myofiber disorganization is due to hemodynamic factors, developmental problems, or both.
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MESH Headings
- Adolescent
- Child, Preschool
- Diffusion Magnetic Resonance Imaging
- Female
- Heart Defects, Congenital/diagnostic imaging
- Heart Defects, Congenital/pathology
- Heart Defects, Congenital/physiopathology
- Heart Defects, Congenital/surgery
- Heart Failure/diagnostic imaging
- Heart Failure/pathology
- Heart Failure/physiopathology
- Heart Failure/surgery
- Heart Transplantation
- Heart Ventricles/diagnostic imaging
- Heart Ventricles/pathology
- Heart Ventricles/physiopathology
- Heart Ventricles/surgery
- Humans
- Male
- Myocardium/pathology
- Myofibrils/pathology
- Predictive Value of Tests
- Ventricular Dysfunction, Right/diagnostic imaging
- Ventricular Dysfunction, Right/pathology
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Dysfunction, Right/surgery
- Ventricular Function, Right
- Young Adult
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Affiliation(s)
- Cosimo M. Campanale
- Unit of Perinatal Cardiology, Department of Neonatology, Ospedale Pediatrico Bambino Gesù di Roma, Rome, Italy
| | - Benoit Scherrer
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Onur Afacan
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Amara Majeed
- Department of Cardiology, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA USA
| | - Simon K. Warfield
- Department of Radiology, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Stephen P. Sanders
- Cardiac Registry, Departments of Cardiology, Pathology and Cardiac Surgery, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA 02115, USA. and Department of Pediatrics, Harvard Medical School, Boston, MA USA
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Holmes JB, Doh CY, Mamidi R, Li J, Stelzer JE. Strategies for targeting the cardiac sarcomere: avenues for novel drug discovery. Expert Opin Drug Discov 2020; 15:457-469. [PMID: 32067508 PMCID: PMC7065952 DOI: 10.1080/17460441.2020.1722637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/24/2020] [Indexed: 01/10/2023]
Abstract
Introduction: Heart failure remains one of the largest clinical challenges in the United States. Researchers have continually searched for more effective heart failure treatments that target the cardiac sarcomere but have found few successes despite numerous expensive cardiovascular clinical trials. Among many reasons, the high failure rate of cardiovascular clinical trials may be partly due to incomplete characterization of a drug candidate's complex interaction with cardiac physiology.Areas covered: In this review, the authors address the issue of preclinical cardiovascular studies of sarcomere-targeting heart failure therapies. The authors consider inherent tradeoffs made between mechanistic transparency and physiological fidelity for several relevant preclinical techniques at the atomic, molecular, heart muscle fiber, whole heart, and whole-organism levels. Thus, the authors suggest a comprehensive, bottom-up approach to preclinical cardiovascular studies that fosters scientific rigor and hypothesis-driven drug discovery.Expert opinion: In the authors' opinion, the implementation of hypothesis-driven drug discovery practices, such as the bottom-up approach to preclinical cardiovascular studies, will be imperative for the successful development of novel heart failure treatments. However, additional changes to clinical definitions of heart failure and current drug discovery culture must accompany the bottom-up approach to maximize the effectiveness of hypothesis-driven drug discovery.
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Affiliation(s)
- Joshua B Holmes
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Chang Yoon Doh
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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6
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Echocardiographic tissue imaging evaluation of myocardial characteristics and function in cardiomyopathies. Heart Fail Rev 2020; 26:813-828. [PMID: 31950337 DOI: 10.1007/s10741-020-09918-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Current echocardiography techniques have allowed more precise assessment of cardiac structure and function of the several types of cardiomyopathies. Parameters derived from echocardiographic tissue imaging (ETI)-tissue Doppler, strain, strain rate, and others-are extensively used to provide a framework in the evaluation and management of cardiomyopathies. Generally, myocardial function assessed by ETI is depressed in all types of cardiomyopathies, non-ischemic dilated cardiomyopathy (DCM) in particular. In hypertrophic cardiomyopathy (HCM), ETI is useful to identify subclinical disease in family members of HCM, to differentiate HCM from other conditions causing cardiac hypertrophy and to predict cardiac events. ETI also for HCM allows addressing the mechanism behind left ventricular outflow tract obstruction and its improvement after therapeutic options. ETI provides cardiac amyloidosis with unique and specific findings such as "apical sparing." Nevertheless, ETI does not seem to provide as much information amenable to histological findings as recently emerging techniques of cardiac magnetic resonance imaging. This review introduces usefulness of ETI and some other ultrasound techniques for detecting clinical and subclinical characteristics of cardiomyopathies, focusing on DCM, HCM, and cardiac amyloidosis.
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Wu XP, Li YD, Zhang M, Zhu WW, Cai QZ, Jiang W, Sun LL, Ding XY, Ye XG, Qin YY, Lu XZ. Impaired left ventricular mechanics and functional reserve are associated with reduced exercise capacity in patients with hypertrophic cardiomyopathy. Echocardiography 2019; 36:266-275. [PMID: 30600556 DOI: 10.1111/echo.14241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 11/22/2018] [Accepted: 11/25/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Reduced metabolic equivalents (METs) are an indicator of exercise intolerance, which predicts poor prognosis in hypertrophic cardiomyopathy (HCM) patients. We sought to evaluate the changes in left ventricular (LV) mechanics and functional reserves, as well as their association with functional capacity in HCM patients. METHODS Seventy HCM patients and thirty controls were included in this study. LV mechanics were evaluated at rest and during exercise by echocardiography and two-dimensional speckle-tracking imaging to obtain parameters of functional reserve, LV global longitudinal strain (LVGLS), strain rate (SR), and circumferential strain. RESULTS Hypertrophic cardiomyopathy (HCM) patients had lower LVGLS, systolic SR, early and late diastolic SR at rest and during exercise, and reduced absolute and relative systolic and diastolic reserve compared to controls. LV circumferential strain was significantly higher at rest but lower during exercise in HCM patients. Exercise capacity was markedly reduced in HCM patients, and peak exercise LVGLS (LVGLS-exe) significantly correlated with exercise capacity. Multivariate regression analyses showed that LVGLS-exe, LV filling pressure during exercise (E/e'-exe), and LV mass index (LVMI) were independent predictors of exercise capacity. Moreover, LVGLS-exe displayed incremental predictive value over E/e'-exe and LVMI for exercise intolerance. Receiver operating characteristic curve analysis showed LVGLS-exe had optimal accuracy for predicting exercise intolerance in HCM patients. CONCLUSIONS Hypertrophic cardiomyopathy (HCM) patients have reduced LV mechanics at rest and during exercise and impaired mechanical reserve. LVGLS-exe is associated with exercise capacity and is an optimal predictive value for reduced exercise capacity in HCM patients.
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Affiliation(s)
- Xiao-Peng Wu
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Yi-Dan Li
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Miao Zhang
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Wei-Wei Zhu
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Qi-Zhe Cai
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Wei Jiang
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Lan-Lan Sun
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Xue-Yan Ding
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Xiao-Guang Ye
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Yun-Yun Qin
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
| | - Xiu-Zhang Lu
- Department of Echocardiography, Heart Center, Beijing Chao Yang Hospital, Capital Medical University, Beijing, China
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Investigation of myocardial dysfunction using three-dimensional speckle tracking echocardiography in a genetic positive hypertrophic cardiomyopathy Chinese family. Cardiol Young 2018; 28:1106-1114. [PMID: 29978770 DOI: 10.1017/s1047951118000860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND We previously reported four heterozygous missense mutations of MYH7, KCNQ1, MYLK2, and TMEM70 in a single three-generation Chinese family with dual Long QT and hypertrophic cardiomyopathy phenotypes for the first time. However, the clinical course among the family members was various, and the potential myocardial dysfunction has not been investigated. OBJECTIVES The objective of this study was to investigate the echocardiographic and electrocardiographic characteristics in a genetic positive Chinese family with hypertrophic cardiomyopathy and further to explore the association between myocardial dysfunction and electric activity, and the identified mutations. METHODS A comprehensive echocardiogram - standard two-dimensional Doppler echocardiography and three-dimensional speckle tracking echocardiography - and electrocardiogram were obtained for members in this family. RESULTS As previously reported, four missense mutations - MYH7-H1717Q, KCNQ1-R190W, MYLK2-K324E, and TMEM70-I147T - were identified in this family. The MYH7-H1717Q mutation carriers had significantly increased left ventricular mass indices, elevated E/e' ratio, deteriorated global longitudinal stain, but enhanced global circumferential and radial strain compared with those in non-mutation patients (all p<0.05). The KCNQ1-R190W carriers showed significantly prolonged QTc intervals, and the MYLK2-K324E mutation carriers showed inverted T-waves (both p<0.05). However, the TMEM70-I147T mutation carriers had similar echocardiography and electrocardiographic data as non-mutation patients. CONCLUSIONS Three of the identified four mutations had potential pathogenic effects in this family: MYH7-H1717Q was associated with increased left ventricular thickness, elevated left ventricular filling pressure, and altered myocardial deformation; KCNQ1-R190W and MYLK2-K324E mutations were correlated with electrocardiographic abnormalities reflected in long QT phenotype and inverted T-waves, respectively.
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Pagourelias ED, Mirea O, Vovas G, Duchenne J, Michalski B, Van Cleemput J, Bogaert J, Vassilikos VP, Voigt JU. Relation of regional myocardial structure and function in hypertrophic cardiomyopathy and amyloidois: a combined two-dimensional speckle tracking and cardiovascular magnetic resonance analysis. Eur Heart J Cardiovasc Imaging 2018; 20:426-437. [DOI: 10.1093/ehjci/jey107] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/12/2018] [Accepted: 07/10/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Efstathios D Pagourelias
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
- Third Cardiology Department, Hippokrateion University Hospital, Aristotle University of Thessaloniki, 49 Konstantinoupoleos Str, Thessaloniki, Greece
| | - Oana Mirea
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
- Department of Cardiology, University of Medicine and Pharmacy of Craiova, University County Hospital of Craiova, 1 Tabaci Str, Craiova, Romania
| | - Georgios Vovas
- Department of Radiology, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
| | - Jürgen Duchenne
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
| | - Blazej Michalski
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
| | - Johan Van Cleemput
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
| | - Jan Bogaert
- Department of Radiology, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
| | - Vasilios P Vassilikos
- Third Cardiology Department, Hippokrateion University Hospital, Aristotle University of Thessaloniki, 49 Konstantinoupoleos Str, Thessaloniki, Greece
| | - Jens-Uwe Voigt
- Department of Cardiovascular Diseases, University Hospital Leuven, Catholic University Leuven, Herestraat 49, Leuven, Belgium
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10
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Wang Y, Ravanfar M, Zhang K, Duan D, Yao G. Automatic quantification of microscopic heart damage in a mouse model of Duchenne muscular dystrophy using optical polarization tractography. JOURNAL OF BIOPHOTONICS 2018; 11:e201700284. [PMID: 29314725 DOI: 10.1002/jbio.201700284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/06/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Abstract
Quantification of microscopic myocardium damage in a diseased heart is important in studying disease progression and evaluating treatment outcome. However, it is challenging to use traditional histology and existing medical imaging modalities to quantify all microscopic damages in a small animal heart. Here, a method was developed for fast visualization and quantification of focal tissue damage in the mouse heart based on the fiber alignment index of the local myofiber organization obtained in optical polarization tractography (OPT). This method was tested in freshly excised hearts of the mdx4cv mouse, a commonly used mouse model for studying Duchenne cardiomyopathy. The hearts of age-matched C57BL/6 mice were also imaged as the normal controls. The results revealed a significant amount of damage in the mdx4cv hearts. Histology comparisons confirmed the damage identified by OPT. This fast and automatic method may greatly enhance preclinical studies in murine models of heart diseases.
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Affiliation(s)
- Yuanbo Wang
- Department of Bioengineering, University of Missouri, Columbia, Missouri
| | | | - Keqing Zhang
- Department of Molecular Microbiology & Immunology, University of Missouri, Columbia, Missouri
| | - Dongsheng Duan
- Department of Bioengineering, University of Missouri, Columbia, Missouri
- Department of Molecular Microbiology & Immunology, University of Missouri, Columbia, Missouri
| | - Gang Yao
- Department of Bioengineering, University of Missouri, Columbia, Missouri
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Abstract
Modern advanced imaging techniques have allowed increasingly more rigorous assessment of the cardiac structure and function of several types of cardiomyopathies. In contemporary cardiology practice, echocardiography and cardiac magnetic resonance imaging are widely used to provide a basic framework in the evaluation and management of cardiomyopathies. Echocardiography is the quintessential imaging technique owing to its unique ability to provide real-time images of the beating heart with good temporal resolution, combined with its noninvasive nature, cost-effectiveness, availability, and portability. Cardiac magnetic resonance imaging provides data that are both complementary and uniquely distinct, thus allowing for insights into the disease process that until recently were not possible. The new catchphrase in the evaluation of cardiomyopathies is multimodality imaging, which is purported to be the efficient integration of various methods of cardiovascular imaging to improve the ability to diagnose, guide therapy, or predict outcomes. It usually involves an integrated approach to the use of echocardiography and cardiac magnetic resonance imaging for the assessment of cardiomyopathies, and, on occasion, single-photon emission computed tomography and such specialized techniques as pyrophosphate scanning.
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Affiliation(s)
- M Fuad Jan
- From Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Milwaukee, WI
| | - A Jamil Tajik
- From Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Milwaukee, WI.
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12
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Characteristic systolic waveform of left ventricular longitudinal strain rate in patients with hypertrophic cardiomyopathy. Heart Vessels 2016; 32:591-599. [PMID: 27757525 DOI: 10.1007/s00380-016-0906-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 10/14/2016] [Indexed: 01/19/2023]
Abstract
We analyzed the waveform of systolic strain and strain-rate curves to find a characteristic left ventricular (LV) myocardial contraction pattern in patients with hypertrophic cardiomyopathy (HCM), and evaluated the utility of these parameters for the differentiation of HCM and LV hypertrophy secondary to hypertension (HT). From global strain and strain-rate curves in the longitudinal and circumferential directions, the time from mitral valve closure to the peak strains (T-LS and T-CS, respectively) and the peak systolic strain rates (T-LSSR and T-CSSR, respectively) were measured in 34 patients with HCM, 30 patients with HT, and 25 control subjects. The systolic strain-rate waveform was classified into 3 patterns ("V", "W", and "√" pattern). In the HCM group, T-LS was prolonged, but T-LSSR was shortened; consequently, T-LSSR/T-LS ratio was distinctly lower than in the HT and control groups. The "√" pattern of longitudinal strain-rate waveform was more frequently seen in the HCM group (74 %) than in the control (4 %) and HT (20 %) groups. Similar but less distinct results were obtained in the circumferential direction. To differentiate HCM from HT, the sensitivity and specificity of the T-LSSR/T-LS ratio <0.34 and the "√"-shaped longitudinal strain-rate waveform were 85 and 63 %, and 74 and 80 %, respectively. In conclusion, in patients with HCM, a reduced T-LSSR/T-LS ratio and a characteristic "√"-shaped waveform of LV systolic strain rate was seen, especially in the longitudinal direction. The timing and waveform analyses of systolic strain rate may be useful to distinguish between HCM and HT.
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13
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Hoffman MP, Taylor EN, Aninwene GE, Sadayappan S, Gilbert RJ. Assessing the multiscale architecture of muscular tissue with Q-space magnetic resonance imaging: Review. Microsc Res Tech 2016; 81:162-170. [PMID: 27696640 DOI: 10.1002/jemt.22777] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 01/14/2023]
Abstract
Contraction of muscular tissue requires the synchronized shortening of myofibers arrayed in complex geometrical patterns. Imaging such myofiber patterns with diffusion-weighted MRI reveals architectural ensembles that underlie force generation at the organ scale. Restricted proton diffusion is a stochastic process resulting from random translational motion that may be used to probe the directionality of myofibers in whole tissue. During diffusion-weighted MRI, magnetic field gradients are applied to determine the directional dependence of proton diffusion through the analysis of a diffusional probability distribution function (PDF). The directions of principal (maximal) diffusion within the PDF are associated with similarly aligned diffusion maxima in adjacent voxels to derive multivoxel tracts. Diffusion-weighted MRI with tractography thus constitutes a multiscale method for depicting patterns of cellular organization within biological tissues. We provide in this review, details of the method by which generalized Q-space imaging is used to interrogate multidimensional diffusion space, and thereby to infer the organization of muscular tissue. Q-space imaging derives the lowest possible angular separation of diffusion maxima by optimizing the conditions by which magnetic field gradients are applied to a given tissue. To illustrate, we present the methods and applications associated with Q-space imaging of the multiscale myoarchitecture associated with the human and rodent tongues. These representations emphasize the intricate and continuous nature of muscle fiber organization and suggest a method to depict structural "blueprints" for skeletal and cardiac muscle tissue.
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Affiliation(s)
- Matthew P Hoffman
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Erik N Taylor
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - George E Aninwene
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University of Chicago, Maywood, IL, 60153, USA
| | - Richard J Gilbert
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
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14
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Taylor EN, Hoffman MP, Barefield DY, Aninwene GE, Abrishamchi AD, Lynch TL, Govindan S, Osinska H, Robbins J, Sadayappan S, Gilbert RJ. Alterations in Multi-Scale Cardiac Architecture in Association With Phosphorylation of Myosin Binding Protein-C. J Am Heart Assoc 2016; 5:e002836. [PMID: 27068630 PMCID: PMC4943261 DOI: 10.1161/jaha.115.002836] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Background The geometric organization of myocytes in the ventricular wall comprises the structural underpinnings of cardiac mechanical function. Cardiac myosin binding protein‐C (MYBPC3) is a sarcomeric protein, for which phosphorylation modulates myofilament binding, sarcomere morphology, and myocyte alignment in the ventricular wall. To elucidate the mechanisms by which MYBPC3 phospho‐regulation affects cardiac tissue organization, we studied ventricular myoarchitecture using generalized Q‐space imaging (GQI). GQI assessed geometric phenotype in excised hearts that had undergone transgenic (TG) modification of phospho‐regulatory serine sites to nonphosphorylatable alanines (MYBPC3AllP−/(t/t)) or phospho‐mimetic aspartic acids (MYBPC3AllP+/(t/t)). Methods and Results Myoarchitecture in the wild‐type (MYBPC3WT) left‐ventricle (LV) varied with transmural position, with helix angles ranging from −90/+90 degrees and contiguous circular orientation from the LV mid‐myocardium to the right ventricle (RV). Whereas MYBPC3AllP+/(t/t) hearts were not architecturally distinct from MYBPC3WT, MYBPC3AllP−/(t/t) hearts demonstrated a significant reduction in LV transmural helicity. Null MYBPC3(t/t) hearts, as constituted by a truncated MYBPC3 protein, demonstrated global architectural disarray and loss in helicity. Electron microscopy was performed to correlate the observed macroscopic architectural changes with sarcomere ultrastructure and demonstrated that impaired phosphorylation of MYBPC3 resulted in modifications of the sarcomere aspect ratio and shear angle. The mechanical effect of helicity loss was assessed through a geometric model relating cardiac work to ejection fraction, confirming the mechanical impairments observed with echocardiography. Conclusions We conclude that phosphorylation of MYBPC3 contributes to the genesis of ventricular wall geometry, linking myofilament biology with multiscale cardiac mechanics and myoarchitecture.
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Affiliation(s)
- Erik N Taylor
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Matthew P Hoffman
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - David Y Barefield
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - George E Aninwene
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Aurash D Abrishamchi
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Thomas L Lynch
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Suresh Govindan
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Hanna Osinska
- Division of Molecular Cardiovascular Biology, Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Jeffrey Robbins
- Division of Molecular Cardiovascular Biology, Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Sakthivel Sadayappan
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Richard J Gilbert
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
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15
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Patterns of intersecting fiber arrays revealed in whole muscle with generalized Q-space imaging. Biophys J 2016; 108:2740-9. [PMID: 26039175 DOI: 10.1016/j.bpj.2015.03.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/01/2015] [Accepted: 03/31/2015] [Indexed: 01/15/2023] Open
Abstract
The multiscale attributes of mammalian muscle confer significant challenges for structural imaging in vivo. To achieve this, we employed a magnetic resonance method, termed "generalized Q-space imaging", that considers the effect of spatially distributed diffusion-weighted magnetic field gradients and diffusion sensitivities on the morphology of Q-space. This approach results in a subvoxel scaled probability distribution function whose shape correlates with local fiber orientation. The principal fiber populations identified within these probability distribution functions can then be associated by streamline methods to create multivoxel tractlike constructs that depict the macroscale orientation of myofiber arrays. We performed a simulation of Q-space input parameters, including magnetic field gradient strength and direction, diffusion sensitivity, and diffusional sampling to determine the optimal achievable fiber angle separation in the minimum scan time. We applied this approach to resolve intravoxel crossing myofiber arrays in the setting of the human tongue, an organ with anatomic complexity based on the presence of hierarchical arrays of intersecting myocytes. Using parameters defined by simulation, we imaged at 3T the fanlike configuration of the human genioglossus and the laterally positioned merging fibers of the styloglossus, inferior longitudinalis, chondroglossus, and verticalis. Comparative scans of the excised mouse tongue at 7T demonstrated similar midline and lateral crossing fiber patterns, whereas histological analysis confirmed the presence and distribution of these myofiber arrays at the microscopic scale. Our results demonstrate a magnetic resonance method for acquiring and displaying diffusional data that defines highly ordered myofiber patterns in architecturally complex tissue. Such patterns suggest inherent multiscale fiber organization and provide a basis for structure-function analyses in vivo and in model tissues.
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16
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Ntelios D, Tzimagiorgis G, Efthimiadis GK, Karvounis H. Mechanical aberrations in hypetrophic cardiomyopathy: emerging concepts. Front Physiol 2015; 6:232. [PMID: 26347658 PMCID: PMC4541419 DOI: 10.3389/fphys.2015.00232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 11/13/2022] Open
Abstract
Hypertrophic cardiomyopathy is the most common monogenic disorder in cardiology. Despite important advances in understanding disease pathogenesis, it is not clear how flaws in individual sarcomere components are responsible for the observed phenotype. The aim of this article is to provide a brief interpretative analysis of some currently proposed pathophysiological mechanisms of hypertrophic cardiomyopathy, with a special emphasis on alterations in the cardiac mechanical properties.
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Affiliation(s)
- Dimitrios Ntelios
- Laboratory of Biological Chemistry, Medical School, Aristotle University of Thessaloniki Thessaloniki, Greece ; Department of Cardiology, AHEPA University Hospital Thessaloniki, Greece
| | - Georgios Tzimagiorgis
- Laboratory of Biological Chemistry, Medical School, Aristotle University of Thessaloniki Thessaloniki, Greece
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17
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Bakermans AJ, Abdurrachim D, Moonen RPM, Motaal AG, Prompers JJ, Strijkers GJ, Vandoorne K, Nicolay K. Small animal cardiovascular MR imaging and spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 88-89:1-47. [PMID: 26282195 DOI: 10.1016/j.pnmrs.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
The use of MR imaging and spectroscopy for studying cardiovascular disease processes in small animals has increased tremendously over the past decade. This is the result of the remarkable advances in MR technologies and the increased availability of genetically modified mice. MR techniques provide a window on the entire timeline of cardiovascular disease development, ranging from subtle early changes in myocardial metabolism that often mark disease onset to severe myocardial dysfunction associated with end-stage heart failure. MR imaging and spectroscopy techniques play an important role in basic cardiovascular research and in cardiovascular disease diagnosis and therapy follow-up. This is due to the broad range of functional, structural and metabolic parameters that can be quantified by MR under in vivo conditions non-invasively. This review describes the spectrum of MR techniques that are employed in small animal cardiovascular disease research and how the technological challenges resulting from the small dimensions of heart and blood vessels as well as high heart and respiratory rates, particularly in mice, are tackled.
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Affiliation(s)
- Adrianus J Bakermans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Rik P M Moonen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Abdallah G Motaal
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Katrien Vandoorne
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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18
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Lohezic M, Teh I, Bollensdorff C, Peyronnet R, Hales PW, Grau V, Kohl P, Schneider JE. Interrogation of living myocardium in multiple static deformation states with diffusion tensor and diffusion spectrum imaging. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:213-25. [PMID: 25117498 PMCID: PMC4210665 DOI: 10.1016/j.pbiomolbio.2014.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/02/2014] [Indexed: 11/27/2022]
Abstract
Diffusion tensor magnetic resonance imaging (MRI) reveals valuable insights into tissue histo-anatomy and microstructure, and has steadily gained traction in the cardiac community. Its wider use in small animal cardiac imaging in vivo has been constrained by its extreme sensitivity to motion, exaggerated by the high heart rates usually seen in rodents. Imaging of the isolated heart eliminates respiratory motion and, if conducted on arrested hearts, cardiac pulsation. This serves as an important intermediate step for basic and translational studies. However, investigating the micro-structural basis of cardiac deformation in the same heart requires observations in different deformation states. Here, we illustrate the imaging of isolated rat hearts in three mechanical states mimicking diastole (cardioplegic arrest), left-ventricular (LV) volume overload (cardioplegic arrest plus LV balloon inflation), and peak systole (lithium-induced contracture). An optimised MRI-compatible Langendorff perfusion setup with the radio-frequency (RF) coil integrated into the wet chamber was developed for use in a 9.4T horizontal bore scanner. Signal-to-noise ratio improved significantly, by 75% compared to a previous design with external RF coil, and stability tests showed no significant changes in mean T1, T2 or LV wall thickness over a 170 min period. In contracture, we observed a significant reduction in mean fractional anisotropy from 0.32 ± 0.02 to 0.28 ± 0.02, as well as a significant rightward shift in helix angles with a decrease in the proportion of left-handed fibres, as referring to the locally prevailing cell orientation in the heart, from 24.9% to 23.3%, and an increase in the proportion of right-handed fibres from 25.5% to 28.4%. LV overload, in contrast, gave rise to a decrease in the proportion of left-handed fibres from 24.9% to 21.4% and an increase in the proportion of right-handed fibres from 25.5% to 26.0%. The modified perfusion and coil setup offers better performance and control over cardiac contraction states. We subsequently performed high-resolution diffusion spectrum imaging (DSI) and 3D whole heart fibre tracking in fixed ex vivo rat hearts in slack state and contracture. As a model-free method, DSI augmented the measurements of water diffusion by also informing on multiple intra-voxel diffusion orientations and non-Gaussian diffusion. This enabled us to identify the transition from right- to left-handed fibres from the subendocardium to the subepicardium, as well as voxels in apical regions that were traversed by multiple fibres. We observed that both the mean generalised fractional anisotropy and mean kurtosis were lower in hearts in contracture compared to the slack state, by 23% and 9.3%, respectively. While its heavy acquisition burden currently limits the application of DSI in vivo, ongoing work in acceleration techniques may enable its use in live animals and patients. This would provide access to the as yet unexplored dimension of non-Gaussian diffusion that could serve as a highly sensitive marker of cardiac micro-structural integrity.
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Affiliation(s)
- Maelene Lohezic
- British Heart Foundation Experimental Magnetic Resonance Unit, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Irvin Teh
- British Heart Foundation Experimental Magnetic Resonance Unit, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Christian Bollensdorff
- National Heart and Lung Institute, Imperial College London, London, UK; Qatar Cardiovascular Research Center, Qatar Foundation, Doha, Qatar
| | - Rémi Peyronnet
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Patrick W Hales
- Imaging and Biophysics Unit, Institute of Child Health, University College London, London, UK
| | - Vicente Grau
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Peter Kohl
- National Heart and Lung Institute, Imperial College London, London, UK; Department of Computer Science, University of Oxford, Oxford, UK
| | - Jürgen E Schneider
- British Heart Foundation Experimental Magnetic Resonance Unit, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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Urbano-Moral JA, Rowin EJ, Maron MS, Crean A, Pandian NG. Investigation of Global and Regional Myocardial Mechanics With 3-Dimensional Speckle Tracking Echocardiography and Relations to Hypertrophy and Fibrosis in Hypertrophic Cardiomyopathy. Circ Cardiovasc Imaging 2014; 7:11-9. [DOI: 10.1161/circimaging.113.000842] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Jose Angel Urbano-Moral
- From the Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA (J.A.U.-M., E.J.R., M.S.M., N.G.P.); and Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Canada (A.C.)
| | - Ethan J. Rowin
- From the Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA (J.A.U.-M., E.J.R., M.S.M., N.G.P.); and Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Canada (A.C.)
| | - Martin S. Maron
- From the Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA (J.A.U.-M., E.J.R., M.S.M., N.G.P.); and Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Canada (A.C.)
| | - Andrew Crean
- From the Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA (J.A.U.-M., E.J.R., M.S.M., N.G.P.); and Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Canada (A.C.)
| | - Natesa G. Pandian
- From the Hypertrophic Cardiomyopathy Center and Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, MA (J.A.U.-M., E.J.R., M.S.M., N.G.P.); and Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Canada (A.C.)
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20
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Sengupta PP, Narula J. LV segmentation and mechanics in HCM: twisting the Rubik's Cube into perfection! JACC Cardiovasc Imaging 2012; 5:765-8. [PMID: 22789952 DOI: 10.1016/j.jcmg.2012.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Desjardins CL, Chen Y, Coulton AT, Hoit BD, Yu X, Stelzer JE. Cardiac myosin binding protein C insufficiency leads to early onset of mechanical dysfunction. Circ Cardiovasc Imaging 2011; 5:127-36. [PMID: 22157650 DOI: 10.1161/circimaging.111.965772] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Decreased expression of cardiac myosin binding protein C (cMyBPC) as a result of genetic mutations may contribute to the development of hypertrophic cardiomyopathy (HCM); however, the mechanisms that link cMyBPC expression and HCM development, especially contractile dysfunction, remain unclear. METHODS AND RESULTS We evaluated cardiac mechanical function in vitro and in vivo in young mice (8-10 weeks of age) carrying no functional cMyBPC alleles (cMyBPC(-/-)) or 1 functional cMyBPC allele (cMyBPC(±)). Skinned myocardium isolated from cMyBPC(-/-) hearts displayed significant accelerations in stretch activation cross-bridge kinetics. Cardiac MRI studies revealed severely depressed in vivo left ventricular (LV) magnitude and rates of LV wall strain and torsion compared with wild-type (WT) mice. Heterozygous cMyBPC(±) hearts expressed 23±5% less cMyBPC than WT hearts but did not display overt hypertrophy. Skinned myocardium isolated from cMyBPC(±) hearts displayed small accelerations in the rate of stretch induced cross-bridge recruitment. MRI measurements revealed reductions in LV torsion and circumferential strain, as well reduced circumferential strain rates in early systole and diastole. CONCLUSIONS Modest decreases in cMyBPC expression in the mouse heart result in early-onset subtle changes in cross-bridge kinetics and in vivo LV mechanical function, which could contribute to the development of HCM later in life.
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Affiliation(s)
- Candida L Desjardins
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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