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Restivo MC, Ramasawmy R, Bandettini WP, Herzka DA, Campbell-Washburn AE. Efficient spiral in-out and EPI balanced steady-state free precession cine imaging using a high-performance 0.55T MRI. Magn Reson Med 2020; 84:2364-2375. [PMID: 32291845 DOI: 10.1002/mrm.28278] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE Low-field MRI offers favorable physical properties for SNR-efficient long readout acquisitions such as spiral and EPI. We used a 0.55 tesla (T) MRI system equipped with high-performance hardware to increase the sampling duty cycle and extend the TR of balanced steady-state free precession (bSSFP) cardiac cine acquisitions, which typically are limited by banding artifacts. METHODS We developed a high-efficiency spiral in-out bSSFP acquisition, with zeroth- and first-gradient moment nulling, and an EPI bSSFP acquisition for cardiac cine imaging using a contemporary MRI system modified to operate at 0.55T. Spiral in-out and EPI bSSFP cine protocols, with TR = 8 ms, were designed to maintain both spatiotemporal resolution and breath-hold length. Simulations, phantom imaging, and healthy volunteer imaging studies (n = 12) were performed to assess SNR and image quality using these high sampling duty-cycle bSSFP sequences. RESULTS Spiral in-out bSSFP performed favorably at 0.55T and generated good image quality, whereas EPI bSSFP suffered motion and flow artifacts. There was no difference in ejection fraction comparing spiral in-out with standard Cartesian imaging. Moreover, human images demonstrated a 79% ± 21% increase in myocardial SNR using spiral in-out bSSFP and 50% ± 14% increase in SNR using EPI bSSFP as compared with the reference Cartesian acquisition. Spiral in-out acquisitions at 0.55T recovered 69% ± 14% of the myocardial SNR at 1.5T. CONCLUSION Efficient bSSFP spiral in-out provided high-quality cardiac cine imaging and SNR recovery on a high-performance 0.55T MRI system.
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Affiliation(s)
- Matthew C Restivo
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - W Patricia Bandettini
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Daniel A Herzka
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
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2
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Gabisonia K, Prosdocimo G, Aquaro GD, Carlucci L, Zentilin L, Secco I, Ali H, Braga L, Gorgodze N, Bernini F, Burchielli S, Collesi C, Zandonà L, Sinagra G, Piacenti M, Zacchigna S, Bussani R, Recchia FA, Giacca M. MicroRNA therapy stimulates uncontrolled cardiac repair after myocardial infarction in pigs. Nature 2019; 569:418-422. [PMID: 31068698 PMCID: PMC6768803 DOI: 10.1038/s41586-019-1191-6] [Citation(s) in RCA: 303] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 04/09/2019] [Indexed: 01/08/2023]
Abstract
Prompt coronary catheterization and revascularization have dramatically improved
the outcome of myocardial infarction, but also have resulted in a growing number of
survived patients with permanent structural damage of the heart, which frequently leads to
heart failure. Finding new treatments for this condition is a largely unmet clinical need
1, especially because of the incapacity of
cardiomyocytes to replicate after birth and thus achieve regeneration of the lost
contractile tissue 2. Here we show that expression
of human microRNA-199a in infarcted pig hearts is capable of stimulating cardiac repair.
One month after myocardial infarction and delivery of this microRNA through an
adeno-associated viral vector, the treated animals showed marked improvements in both
global and regional contractility, increased muscle mass and reduced scar size. These
functional and morphological findings correlated with cardiomyocyte de-differentiation and
proliferation. At longer follow-up, however, persistent and uncontrolled expression of the
microRNA resulted in sudden arrhythmic death of most of the treated pigs. Such events were
concurrent with myocardial infiltration of proliferating cells displaying a poorly
differentiated myoblastic phenotype. These results show that achieving cardiac repair
through the stimulation of endogenous cardiomyocyte proliferation is attainable in large
mammals, however this therapy needs to be tightly dosed.
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Affiliation(s)
- Khatia Gabisonia
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Giulia Prosdocimo
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | | | - Lucia Carlucci
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Lorena Zentilin
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Ilaria Secco
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre, London, UK
| | - Hashim Ali
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre, London, UK
| | - Luca Braga
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre, London, UK
| | - Nikoloz Gorgodze
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fabio Bernini
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | | | - Chiara Collesi
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Lorenzo Zandonà
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Gianfranco Sinagra
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | | | - Serena Zacchigna
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.,Cardiovascular Biology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Rossana Bussani
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Fabio A Recchia
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy. .,Fondazione Toscana Gabriele Monasterio, Pisa, Italy. .,Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA.
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy. .,School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre, London, UK. .,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.
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3
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Malliaras K, Makkar RR, Smith RR, Cheng K, Wu E, Bonow RO, Marbán L, Mendizabal A, Cingolani E, Johnston PV, Gerstenblith G, Schuleri KH, Lardo AC, Marbán E. Intracoronary cardiosphere-derived cells after myocardial infarction: evidence of therapeutic regeneration in the final 1-year results of the CADUCEUS trial (CArdiosphere-Derived aUtologous stem CElls to reverse ventricUlar dySfunction). J Am Coll Cardiol 2014; 63:110-22. [PMID: 24036024 PMCID: PMC3947063 DOI: 10.1016/j.jacc.2013.08.724] [Citation(s) in RCA: 362] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/21/2013] [Accepted: 08/19/2013] [Indexed: 12/14/2022]
Abstract
OBJECTIVES This study sought to report full 1-year results, detailed magnetic resonance imaging analysis, and determinants of efficacy in the prospective, randomized, controlled CADUCEUS (CArdiosphere-Derived aUtologous stem CElls to reverse ventricUlar dySfunction) trial. BACKGROUND Cardiosphere-derived cells (CDCs) exerted regenerative effects at 6 months in the CADUCEUS trial. Complete results at the final 1-year endpoint are unknown. METHODS Autologous CDCs (12.5 to 25 × 10(6)) grown from endomyocardial biopsy specimens were infused via the intracoronary route in 17 patients with left ventricular dysfunction 1.5 to 3 months after myocardial infarction (MI) (plus 1 infused off-protocol 14 months post-MI). Eight patients were followed as routine-care control patients. RESULTS In 13.4 months of follow-up, safety endpoints were equivalent between groups. At 1 year, magnetic resonance imaging revealed that CDC-treated patients had smaller scar size compared with control patients. Scar mass decreased and viable mass increased in CDC-treated patients but not in control patients. The single patient infused 14 months post-MI responded similarly. CDC therapy led to improved regional function of infarcted segments compared with control patients. Scar shrinkage correlated with an increase in viability and with improvement in regional function. Scar reduction correlated with baseline scar size but not with a history of temporally remote MI or time from MI to infusion. The changes in left ventricular ejection fraction in CDC-treated subjects were consistent with the natural relationship between scar size and ejection fraction post-MI. CONCLUSIONS Intracoronary administration of autologous CDCs did not raise significant safety concerns. Preliminary indications of bioactivity include decreased scar size, increased viable myocardium, and improved regional function of infarcted myocardium at 1 year post-treatment. These results, which are consistent with therapeutic regeneration, merit further investigation in future trials. (CArdiosphere-Derived aUtologous stem CElls to reverse ventricUlar dySfunction [CADUCEUS]; NCT00893360).
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MESH Headings
- Aged
- Biopsy
- Coronary Vessels
- Electrocardiography, Ambulatory
- Female
- Follow-Up Studies
- Heart Ventricles/pathology
- Heart Ventricles/physiopathology
- Humans
- Injections, Intra-Arterial
- Magnetic Resonance Imaging, Cine
- Male
- Middle Aged
- Myocardial Infarction/complications
- Myocardial Infarction/physiopathology
- Myocardial Infarction/surgery
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/transplantation
- Recovery of Function
- Stem Cell Transplantation/methods
- Time Factors
- Transplantation, Autologous
- Treatment Outcome
- Ventricular Dysfunction, Left/etiology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/surgery
- Ventricular Function, Left/physiology
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Affiliation(s)
| | - Raj R Makkar
- Cedars-Sinai Heart Institute, Los Angeles, California
| | | | - Ke Cheng
- Cedars-Sinai Heart Institute, Los Angeles, California
| | - Edwin Wu
- Division of Cardiology, Department of Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois
| | - Robert O Bonow
- Division of Cardiology, Department of Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois
| | - Linda Marbán
- Cedars-Sinai Heart Institute, Los Angeles, California
| | | | | | - Peter V Johnston
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Gary Gerstenblith
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Karl H Schuleri
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Albert C Lardo
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, Maryland; Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland
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4
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Multiacquisition T1-mapping MRI during tidal respiration for quantification of myocardial T1 in swine with heart failure. AJR Am J Roentgenol 2013; 201:W563-70. [PMID: 24059393 DOI: 10.2214/ajr.12.8659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this article is to evaluate a free-breathing pulse sequence to quantify myocardial T1 changes in a swine model of tachycardia-induced heart failure. MATERIALS AND METHODS Yorkshire swine were implanted with pacemakers and were ventricularly paced at 200 beats/min to induce heart failure. Animals were scanned twice with a 1.5-T MRI scanner, once at baseline and once at heart failure. A T1-mapping sequence was performed during tidal respiration before and 5 minutes after the administration of a gadolinium-chelate contrast agent. T1-mapping values were compared between the baseline and heart failure scans. The percentage of fibrosis of heart failure myocardial tissue was compared with similar left ventricular tissue from control animals using trichrome blue histologic analysis. RESULTS In the study cohort, differences were found between the baseline and heart failure T1-mapping values before the administration of contrast agent (960 ± 96 and 726 ± 94 ms, respectively; p = 0.02) and after contrast agent administration (546 ± 180 and 300 ± 171 ms, respectively; p = 0.005). The animals with heart failure also had a difference histologically in the percentage of myocardial collagen compared with tissue from healthy control animals (control, 5.4% ± 1.0%; heart failure, 9.4% ± 1.6%; p < 0.001). CONCLUSION The proposed T1-mapping technique can quantify diffuse myocardial changes associated with heart failure without the use of a contrast agent and without breath-holding. These T1 changes appear to be associated with increases in the percentage of myocardial collagen that in this study were not detected by traditional myocardial delayed enhancement imaging. T1 mapping may be a useful technique for detecting early but clinically significant myocardial fibrosis.
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5
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Trung VN, Yamamoto H, Furukawa A, Yamaguchi T, Murata S, Yoshimura M, Murakami Y, Sato S, Otani H, Ugi S, Morino K, Maegawa H, Tani T. Enhanced Intestinal Motility during Oral Glucose Tolerance Test after Laparoscopic Sleeve Gastrectomy: Preliminary Results Using Cine Magnetic Resonance Imaging. PLoS One 2013; 8:e65739. [PMID: 23823622 PMCID: PMC3688799 DOI: 10.1371/journal.pone.0065739] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/26/2013] [Indexed: 12/11/2022] Open
Abstract
Background Enhanced secretion of glucagon-like peptide-1 (GLP-1) has been suggested as a possible mechanism underlying the improvement in type 2 diabetes mellitus (T2DM) after laparoscopic sleeve gastrectomy (LSG). However, the reason for enhanced GLP-1 secretion during glucose challenge after LSG remains unclear because LSG does not include intestinal bypass. In this study, we focused on the effects of LSG on GLP-1 secretion and intestinal motility during the oral glucose tolerance test (OGTT) using cine magnetic resonance imaging (MRI) before and 3 months after LSG. Methods LSG was performed in 12 obese patients with a body mass index >35 kg/m2. Six patients had T2DM. OGTT was performed before and 3 months after the surgery. Body weight, hemoglobin A1c (HbA1c), and GLP-1 levels during OGTT were examined, and intestinal motility during OGTT was assessed using cine MRI. Results Body weight was significantly decreased after surgery in all the cases. HbA1c was markedly decreased in all the diabetic subjects. In all cases, GLP-1 secretion during OGTT was enhanced and cine MRI showed markedly increased intestinal motility at 15 and 30 min during OGTT after LSG. Conclusions LSG leads to accelerated intestinal motility and reduced intestinal transit time, which may be involved in the mechanism underlying enhanced GLP-1 secretion during OGTT after LSG.
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Affiliation(s)
- Vo Nguyen Trung
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Hiroshi Yamamoto
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
- * E-mail:
| | - Akira Furukawa
- Department of Radiology, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Tsuyoshi Yamaguchi
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Satoshi Murata
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Masahiro Yoshimura
- Department of Radiology, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Yoko Murakami
- Department of Radiology, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Shigetaka Sato
- Department of Radiology, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Hideji Otani
- Department of Radiology, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Satoshi Ugi
- Department of Medicine Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Katsutaro Morino
- Department of Medicine Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Hiroshi Maegawa
- Department of Medicine Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
| | - Tohru Tani
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
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6
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Schuleri KH, Centola M, Evers KS, Zviman A, Evers R, Lima JAC, Lardo AC. Cardiovascular magnetic resonance characterization of peri-infarct zone remodeling following myocardial infarction. J Cardiovasc Magn Reson 2012; 14:24. [PMID: 22510220 PMCID: PMC3352163 DOI: 10.1186/1532-429x-14-24] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 04/17/2012] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Clinical studies implementing late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) studies suggest that the peri-infarct zone (PIZ) contains a mixture of viable and non-viable myocytes, and is associated with greater susceptibility to ventricular tachycardia induction and adverse cardiac outcomes. However, CMR data assessing the temporal formation and functional remodeling characteristics of this complex region are limited. We intended to characterize early temporal changes in scar morphology and regional function in the PIZ. METHODS AND RESULTS CMR studies were performed at six time points up to 90 days after induction of myocardial infarction (MI) in eight minipigs with reperfused, anterior-septal infarcts. Custom signal density threshold algorithms, based on the remote myocardium, were applied to define the infarct core and PIZ region for each time point. After the initial post-MI edema subsided, the PIZ decreased by 54% from day 10 to day 90 (p = 0.04). The size of infarct scar expanded by 14% and thinned by 56% from day 3 to 12 weeks (p = 0.004 and p < 0.001, respectively). LVEDV increased from 34.7. ± 2.2 ml to 47.8 ± 3.0 ml (day 3 and week 12, respectively; p < 0.001). At 30 days post-MI, regional circumferential strain was increased between the infarct scar and the PIZ (-2.1 ± 0.6 and -6.8 ± 0.9, respectively;* p < 0.05). CONCLUSIONS The PIZ is dynamic and decreases in mass following reperfused MI. Tensile forces in the PIZ undergo changes following MI. Remodeling characteristics of the PIZ may provide mechanistic insights into the development of life-threatening arrhythmias and sudden cardiac death post-MI.
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Affiliation(s)
- Karl H Schuleri
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
| | - Marco Centola
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
- Azienda Ospedaliera San Paolo, Polo Universitario, Milan, Italy
| | - Kristine S Evers
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
| | - Adam Zviman
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
| | - Robert Evers
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
- Radiology and Imaging Sciences, National Institutes of Health (NIH), Bethesda, MD, USA
| | - João AC Lima
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
| | - Albert C Lardo
- Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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7
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Schuleri KH, Centola M, Choi SH, Evers KS, Dawoud F, George RT, Lima JAC, Lardo AC. CT for evaluation of myocardial cell therapy in heart failure: a comparison with CMR imaging. JACC Cardiovasc Imaging 2012; 4:1284-93. [PMID: 22172785 DOI: 10.1016/j.jcmg.2011.09.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/29/2011] [Accepted: 09/02/2011] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The aim of this study was to use multidetector computed tomography (MDCT) to assess therapeutic effects of myocardial regenerative cell therapies. BACKGROUND Cell transplantation is being widely investigated as a potential therapy in heart failure. Noninvasive imaging techniques are frequently used to investigate therapeutic effects of cell therapies in the preclinical and clinical settings. Previous studies have shown that cardiac MDCT can accurately quantify myocardial scar tissue and determine left ventricular (LV) volumes and ejection fraction (LVEF). METHODS Twenty-two minipigs were randomized to intramyocardial injection of phosphate-buffered saline (placebo, n = 9) or 200 million mesenchymal stem cells (MSC, n = 13) 12 weeks after myocardial infarction (MI). Cardiac magnetic resonance and MDCT acquisitions were performed before randomization (12 weeks after MI induction) and at the study endpoint 24 weeks after MI induction. None of the animals received medication to control the intrinsic heart rate during first-pass acquisitions for assessment of LV volumes and LVEF. Delayed-enhancement MDCT imaging was performed 10 min after contrast delivery. Two blinded observers analyzed MDCT acquisitions. RESULTS MDCT demonstrated that MSC therapy resulted in a reduction of infarct size from 14.3 ± 1.2% to 10.3 ± 1.5% of LV mass (p = 0.005), whereas infarct size increased in nontreated animals (from 13.8 ± 1.3% to 16.5 ± 1.5%; p = 0.02) (placebo vs. MSC; p = 0.003). Both observers had excellent agreement for infarct size (r = 0.96; p < 0.001). LVEF increased from 32.6 ± 2.2% to 36.9 ± 2.7% in MSC-treated animals (p = 0.03) and decreased in placebo animals (from 33.3 ± 1.4% to 29.1 ± 1.5%; p = 0.01; at week 24: placebo vs. MSC; p = 0.02). Infarct size, end-diastolic LV volume, and LVEF assessed by MDCT compared favorably with those assessed by cardiac magnetic resonance acquisitions (r = 0.70, r = 0.82, and r = 0.902, respectively; p < 0.001). CONCLUSIONS This study demonstrated that cardiac MDCT can be used to evaluate infarct size, LV volumes, and LVEF after intramyocardial-delivered MSC therapy. These findings support the use of cardiac MDCT in preclinical and clinical studies for novel myocardial therapies.
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Affiliation(s)
- Karl H Schuleri
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA.
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8
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Wakamiya M, Furukawa A, Kanasaki S, Murata K. Assessment of small bowel motility function with cine-MRI using balanced steady-state free precession sequence. J Magn Reson Imaging 2011; 33:1235-40. [PMID: 21509884 DOI: 10.1002/jmri.22529] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To evaluate the use of cine-magnetic resonance imaging (MRI) with a steady-state free precession sequence to monitor and assess small bowel motility. MATERIALS AND METHODS Sequential MRI, using a balanced steady-state free precession sequence, was performed in eight healthy male volunteers at 0, 15, 30, 45, and 60 minutes after oral administration of 1500 mL of nonabsorbable fluid to monitor small bowel contractions. Using the cine-mode display, small bowel contractions were reviewed and the luminal diameter was measured on each image to obtain frequency and amplitude of bowel contractions. RESULTS The oral preparation was well tolerated without major complications. Cine-MRI provided high temporal, spatial, and contrast resolution for monitoring bowel contractions. Mean values with standard deviations of frequency and amplitude of bowel contractions were 6.0 ± 2.98/min and 10.4 ± 4.53 mm, respectively, and were 5.1 ± 3.38/min and 9.59 ± 5.57 mm at the jejunal loops and 6.9 ± 2.22/min and 11.2 ± 3.06 mm at the ileal loops. With the passage of luminal fluid, frequency of bowel contractions decreased and the bowels tended to pause their contractions. CONCLUSION Cine-MRI provides sufficient dynamic images to observe small bowel contractions. Measurement of bowel caliber permits calculation of amplitude and frequency of the contractions for characterization and quantitative assessment of small bowel motility function.
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Affiliation(s)
- Makoto Wakamiya
- Radiology Department of Shiga University of Medical Science, Shiga, Japan.
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9
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Simioniuc A, Campan M, Lionetti V, Marinelli M, Aquaro GD, Cavallini C, Valente S, Di Silvestre D, Cantoni S, Bernini F, Simi C, Pardini S, Mauri P, Neglia D, Ventura C, Pasquinelli G, Recchia FA. Placental stem cells pre-treated with a hyaluronan mixed ester of butyric and retinoic acid to cure infarcted pig hearts: a multimodal study. Cardiovasc Res 2011; 90:546-556. [PMID: 21257613 DOI: 10.1093/cvr/cvr018] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
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10
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Tsao J. Ultrafast imaging: Principles, pitfalls, solutions, and applications. J Magn Reson Imaging 2010; 32:252-66. [DOI: 10.1002/jmri.22239] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Schuleri KH, Feigenbaum GS, Centola M, Weiss ES, Zimmet JM, Turney J, Kellner J, Zviman MM, Hatzistergos KE, Detrick B, Conte JV, McNiece I, Steenbergen C, Lardo AC, Hare JM. Autologous mesenchymal stem cells produce reverse remodelling in chronic ischaemic cardiomyopathy. Eur Heart J 2009; 30:2722-32. [PMID: 19586959 DOI: 10.1093/eurheartj/ehp265] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIMS The ability of mesenchymal stem cells (MSCs) to heal the chronically injured heart remains controversial. Here we tested the hypothesis that autologous MSCs can be safely injected into a chronic myocardial infarct scar, reduce its size, and improve ventricular function. METHODS AND RESULTS Female adult Göttingen swine (n = 15) underwent left anterior descending coronary artery balloon occlusion to create reproducible ischaemia-reperfusion infarctions. Bone-marrow-derived MSCs were isolated and expanded from each animal. Twelve weeks post-myocardial infarction (MI), animals were randomized to receive surgical injection of either phosphate buffered saline (placebo, n = 6), 20 million (low dose, n = 3), or 200 million (high dose, n = 6) autologous MSCs in the infarct and border zone. Injections were administered to the beating heart via left anterior thoracotomy. Serial cardiac magnetic resonance imaging was performed to evaluate infarct size, myocardial blood flow (MBF), and left ventricular (LV) function. There was no difference in mortality, post-injection arrhythmias, cardiac enzyme release, or systemic inflammatory markers between groups. Whereas MI size remained constant in placebo and exhibited a trend towards reduction in low dose, high-dose MSC therapy reduced infarct size from 18.2 +/- 0.9 to 14.4 +/- 1.0% (P = 0.02) of LV mass. In addition, both low and high-dose treatments increased regional contractility and MBF in both infarct and border zones. Ectopic tissue formation was not observed with MSCs. CONCLUSION Together these data demonstrate that autologous MSCs can be safely delivered in an adult heart failure model, producing substantial structural and functional reverse remodelling. These findings demonstrate the safety and efficacy of autologous MSC therapy and support clinical trials of MSC therapy in patients with chronic ischaemic cardiomyopathy.
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Affiliation(s)
- Karl H Schuleri
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
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12
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Schuleri KH, Centola M, George RT, Amado LC, Evers KS, Kitagawa K, Vavere AL, Evers R, Hare JM, Cox C, McVeigh ER, Lima JAC, Lardo AC. Characterization of peri-infarct zone heterogeneity by contrast-enhanced multidetector computed tomography: a comparison with magnetic resonance imaging. J Am Coll Cardiol 2009; 53:1699-707. [PMID: 19406346 DOI: 10.1016/j.jacc.2009.01.056] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/09/2009] [Accepted: 01/16/2009] [Indexed: 01/24/2023]
Abstract
OBJECTIVES This study examined whether multidetector computed tomography (MDCT) improves the ability to define peri-infarct zone (PIZ) heterogeneity relative to magnetic resonance imaging (MRI). BACKGROUND The PIZ as characterized by delayed contrast-enhancement (DE)-MRI identifies patients susceptible to ventricular arrhythmias and predicts outcome after myocardial infarction (MI). METHODS Fifteen mini-pigs underwent coronary artery occlusion followed by reperfusion. Both MDCT and MRI were performed on the same day approximately 6 months after MI induction, followed by animal euthanization and ex vivo MRI (n = 5). Signal density threshold algorithms were applied to MRI and MDCT datasets reconstructed at various slice thicknesses (1 to 8 mm) to define the PIZ and to quantify partial volume effects. RESULTS The DE-MDCT reconstructed at 8-mm slice thickness showed excellent correlation of infarct size with post-mortem pathology (r2 = 0.97; p < 0.0001) and MRI (r2 = 0.92; p < 0.0001). The DE-MDCT and -MRI were able to detect a PIZ in all animals, which correlates to a mixture of viable and nonviable myocytes at the PIZ by histology. The ex vivo DE-MRI PIZ volume decreased with slice thickness from 0.9 +/- 0.2 ml at 8 mm to 0.2 +/- 0.1 ml at 1 mm (p = 0.01). The PIZ volume/mass by DE-MDCT increased with decreasing slice thickness because of declining partial volume averaging in the PIZ, but was susceptible to increased image noise. CONCLUSIONS A DE-MDCT provides a more detailed assessment of the PIZ in chronic MI and is less susceptible to partial volume effects than MRI. This increased resolution best reflects the extent of tissue mixture by histopathology and has the potential to further enhance the ability to define the substrate of malignant arrhythmia in ischemic heart disease noninvasively.
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Affiliation(s)
- Karl H Schuleri
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland 21205, USA
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13
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Noninvasive quantitative measurement of myocardial and whole-body oxygen consumption using MRI: initial results. Magn Reson Imaging 2009; 27:147-54. [DOI: 10.1016/j.mri.2008.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 05/17/2008] [Accepted: 06/17/2008] [Indexed: 11/19/2022]
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14
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Schuleri KH, Amado LC, Boyle AJ, Centola M, Saliaris AP, Gutman MR, Hatzistergos KE, Oskouei BN, Zimmet JM, Young RG, Heldman AW, Lardo AC, Hare JM. Early improvement in cardiac tissue perfusion due to mesenchymal stem cells. Am J Physiol Heart Circ Physiol 2008; 294:H2002-11. [PMID: 18310523 DOI: 10.1152/ajpheart.00762.2007] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The underlying mechanism(s) of improved left ventricular function (LV) due to mesenchymal stem cell (MSC) administration after myocardial infarction (MI) remains highly controversial. Myocardial regeneration and neovascularization, which leads to increased tissue perfusion, are proposed mechanisms. Here we demonstrate that delivery of MSCs 3 days after MI increased tissue perfusion in a manner that preceded improved LV function in a porcine model. MI was induced in pigs by 60-min occlusion of the left anterior descending coronary artery, followed by reperfusion. Pigs were assigned to receive intramyocardial injection of allogeneic MSCs (200 million, approximately 15 injections) (n = 10), placebo (n = 6), or no intervention (n = 8). Resting myocardial blood flow (MBF) was serially assessed by first-pass perfusion magnetic resonance imaging (MRI) over an 8-wk period. Over the first week, resting MBF in the infarct area of MSC-treated pigs increased compared with placebo-injected and untreated animals [0.17 +/- 0.03, 0.09 +/- 0.01, and 0.08 +/- 0.01, respectively, signal intensity ratio of MI to left ventricular blood pool (LVBP); P < 0.01 vs. placebo, P < 0.01 vs. nontreated]. In contrast, the signal intensity ratios of the three groups were indistinguishable at weeks 4 and 8. However, MSC-treated animals showed larger, more mature vessels and less apoptosis in the infarct zones and improved regional and global LV function at week 8. Together these findings suggest that an early increase in tissue perfusion precedes improvements in LV function and a reduction in apoptosis in MSC-treated hearts. Cardiac MRI-based measures of blood flow may be a useful tool to predict a successful myocardial regenerative process after MSC treatment.
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Affiliation(s)
- Karl H Schuleri
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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15
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Nayak KS, Lee HL, Hargreaves BA, Hu BS. Wideband SSFP: alternating repetition time balanced steady state free precession with increased band spacing. Magn Reson Med 2008; 58:931-8. [PMID: 17969129 DOI: 10.1002/mrm.21296] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Balanced steady-state free precession (SSFP) imaging is limited by off-resonance banding artifacts, which occur with periodicity 1/TR in the frequency spectrum. A novel balanced SSFP technique for widening the band spacing in the frequency response is described. This method, called wideband SSFP, utilizes two alternating repetition times with alternating RF phase, and maintains high SNR and T(2)/T(1) contrast. For a fixed band spacing, this method can enable improvements in spatial resolution compared to conventional SSFP. Alternatively, for a fixed readout duration this method can widen the band spacing, and potentially avoid the banding artifacts in conventional SSFP. The method is analyzed using simulations and phantom experiments, and is applied to the reduction of banding artifacts in cine cardiac imaging and high-resolution knee imaging at 3T.
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Affiliation(s)
- Krishna S Nayak
- Magnetic Resonance Engineering Laboratory, Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA.
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16
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Abstract
Conventional phase-contrast (PC) MRI is limited in the temporal resolution (typically 50 ms) that can be achieved, due to the need to implement bipolar velocity encoding gradients. PC using steady-state free precession (SSFP) has recently been developed to acquire PC data at higher rates without sacrificing contrast-to-noise ratio (CNR). This work presents two multiecho SSFP PC implementations that can be used to increase the time efficiency of PCSSFP. Both approaches (extrinsic and intrinsic) enable reference image lines to be acquired within the same TR as the flow-encoded lines, thus minimizing the scan time and permitting TR-equivalent temporal resolutions. Both approaches have been implemented and tested successfully on human volunteers at 1.5T and 3T. While the intrinsic approach is useful for encoding higher velocity flows in-plane, the extrinsic implementation can be used for studying a wider range of encoding velocities for flow in the imaging plane and through the imaging plane.
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Affiliation(s)
- Vinay M Pai
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA.
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17
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Lionetti V, Guiducci L, Simioniuc A, Aquaro GD, Simi C, De Marchi D, Burchielli S, Pratali L, Piacenti M, Lombardi M, Salvadori P, Pingitore A, Neglia D, Recchia FA. Mismatch between uniform increase in cardiac glucose uptake and regional contractile dysfunction in pacing-induced heart failure. Am J Physiol Heart Circ Physiol 2007; 293:H2747-56. [PMID: 17704291 DOI: 10.1152/ajpheart.00592.2007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased glucose utilization and regional differences in contractile function are well-known alterations of the failing heart and play an important pathophysiological role. We tested whether, similar to functional derangement, changes in glucose uptake develop following a regional pattern. Heart failure was induced in 13 chronically instrumented minipigs by pacing the left ventricular (LV) free wall at 180 beats/min for 3 wk. Regional changes in contractile function and stress were assessed by magnetic resonance imaging, whereas regional flow and glucose uptake were measured by positron emission tomography utilizing, respectively, the radiotracers [(13)N]ammonia and (18)F-deoxyglucose. In heart failure, LV end-diastolic pressure was 20 +/- 4 mmHg, and ejection fraction was 35 +/- 4% (all P < 0.05 vs. control). Sustained pacing-induced dyssynchronous LV activation caused a more pronounced decrease in LV systolic thickening (7.45 +/- 3.42 vs. 30.62 +/- 8.73%, P < 0.05) and circumferential shortening (-4.62 +/- 1.0 vs. -7.33 +/- 1.2%, P < 0.05) in the anterior/anterior-lateral region (pacing site) compared with the inferoseptal region (opposite site). Conversely, flow was reduced significantly by approximately 32% compared with control and was lower in the opposite site region. Despite these nonhomogeneous alterations, regional end-systolic wall stress was uniformly increased by 60% in the failing LV. Similar to wall stress, glucose uptake markedly increased vs. control (0.24 +/- 0.004 vs. 0.07 +/- 0.01 micromol x min(-1) x g(-1), P < 0.05), with no significant regional differences. In conclusion, high-frequency pacing of the LV free wall causes a dyssynchronous pattern of contraction that leads to progressive cardiac failure with a marked mismatch between increased glucose uptake and regional contractile dysfunction.
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Affiliation(s)
- Vincenzo Lionetti
- Sector of Medicine, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 56122 Pisa, Italy
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18
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Lu A, Grist TM, Block WF. Fat/water separation in single acquisition steady-state free precession using multiple echo radial trajectories. Magn Reson Med 2006; 54:1051-7. [PMID: 16217786 DOI: 10.1002/mrm.20715] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Phase detection in fully refocused SSFP imaging has recently allowed fat/water separation without preparing the magnetization or using multiple acquisitions. Instead, it exploits the phase difference between fat and water at an echo time at the midpoint of the TR. To minimize the TR for improved robustness to B0 inhomogeneity, a 3D projection acquisition collecting two half echoes at the beginning and end of each excitation was previously implemented. Since echoes are not formed at the midpoint of the TR, this method still requires two passes of k-space for fat/water separation. A new method is presented to linearly combine the half echoes to separate fat and water in a single acquisition. Separation using phase detection provides superior contrast between fat and water voxels. Results from high resolution angiography and musculoskeletal studies with improved robustness to inhomogeneity and a 50% scan time reduction compared to the two pass method are presented.
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Affiliation(s)
- Aiming Lu
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53792-3252, USA
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19
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Li G, Park SE, DeFrate LE, Schutzer ME, Ji L, Gill TJ, Rubash HE. The cartilage thickness distribution in the tibiofemoral joint and its correlation with cartilage-to-cartilage contact. Clin Biomech (Bristol, Avon) 2005; 20:736-44. [PMID: 15963613 DOI: 10.1016/j.clinbiomech.2005.04.001] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 03/30/2005] [Accepted: 04/01/2005] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The objective of this study was to investigate whether regions of cartilage in the tibiofemoral joint where cartilage-to-cartilage contact occurred was thicker than other regions. DESIGN In vivo human subjects. BACKGROUND The thickness of the cartilage in the knee has been investigated in various studies. However, the factors that influence the thickness distribution within the joint remain unclear. METHODS Six healthy living knees (5 male, 1 female, average age = 27) were scanned using magnetic resonance imaging. Three-dimensional models of the tibial and femoral cartilage layers were created. The cartilage thickness distribution was compared between regions where cartilage-to-cartilage contact was observed during in vivo weightbearing flexion and regions with no contact. RESULTS The regions with cartilage-to-cartilage contact were significantly thicker than the regions without cartilage-to-cartilage contact (P < 0.05). On the medial condyle, the cartilage-to-cartilage contact regions were up to 40% thicker than regions with no contact. On the lateral femoral condyle, the maximum difference between these regions was 20%. On the tibial plateau, the maximal differences between regions with and without cartilage-to-cartilage contact were found to be 40% on the medial side and 50% on the lateral side. CONCLUSIONS The data suggested that in normal knees, the cartilage was thicker in regions where cartilage-to-cartilage contact was present. Future studies should investigate the effects of in vivo loading on cartilage maintenance and growth. Relevance Injuries that alter knee kinematics might load regions of the joint where the cartilage is thinner. This might alter the stress distributions within the cartilage.
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Affiliation(s)
- Guoan Li
- Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA.
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20
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Amado LC, Saliaris AP, Schuleri KH, St John M, Xie JS, Cattaneo S, Durand DJ, Fitton T, Kuang JQ, Stewart G, Lehrke S, Baumgartner WW, Martin BJ, Heldman AW, Hare JM. Cardiac repair with intramyocardial injection of allogeneic mesenchymal stem cells after myocardial infarction. Proc Natl Acad Sci U S A 2005; 102:11474-9. [PMID: 16061805 PMCID: PMC1183573 DOI: 10.1073/pnas.0504388102] [Citation(s) in RCA: 769] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Although clinical trials of autologous whole bone marrow for cardiac repair demonstrate promising results, many practical and mechanistic issues regarding this therapy remain highly controversial. Here, we report the results of a randomized study of bone-marrow-derived mesenchymal stem cells, administered to pigs, which offer several new insights regarding cellular cardiomyoplasty. First, cells were safely injected by using a percutaneous-injection catheter 3 d after myocardial infarction. Second, cellular transplantation resulted in long-term engraftment, profound reduction in scar formation, and near-normalization of cardiac function. Third, transplanted cells were pre-prepared from an allogeneic donor and were not rejected, a major practical advance for widespread application of this therapy. Together, these findings demonstrate that the direct injection of cellular grafts into damaged myocardium is safe and effective in the perii-nfarct period. The direct delivery of cells to necrotic myocardium offers a valuable alternative to intracoronary cell injections, and the use of allogeneic mesenchymal stem cells provides a valuable strategy for cardiac regenerative therapy that avoids the need for preparing autologous cells from the recipient.
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Affiliation(s)
- Luciano C Amado
- Department of Medicine, Cardiology Division, The Johns Hopkins Hospital, Blalock 618, 600 North Wolfe Street, Baltimore, MD 21287, USA
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21
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Villanueva O, Atkinson DS, Lambert SR. Trigeminal nerve hypoplasia and aplasia in children with goldenhar syndrome and corneal hypoesthesia. J AAPOS 2005; 9:202-4. [PMID: 15838455 DOI: 10.1016/j.jaapos.2004.12.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olga Villanueva
- Emory Eye Center, Emory University, 1365-B Clifton Road NE, Atlanta, GA 30322, USA
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22
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Nayak KS, Hargreaves BA, Hu BS, Nishimura DG, Pauly JM, Meyer CH. Spiral balanced steady-state free precession cardiac imaging. Magn Reson Med 2005; 53:1468-73. [PMID: 15906302 DOI: 10.1002/mrm.20489] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Balanced steady-state free precession (SSFP) sequences are useful in cardiac imaging because they achieve high signal efficiency and excellent blood-myocardium contrast. Spiral imaging enables the efficient acquisition of cardiac images with reduced flow and motion artifacts. Balanced SSFP has been combined with spiral imaging for real-time interactive cardiac MRI. New features of this method to enable scanning in a clinical setting include short, first-moment nulled spiral trajectories and interactive control over the spatial location of banding artifacts (SSFP-specific signal variations). The feasibility of spiral balanced SSFP cardiac imaging at 1.5 T is demonstrated. In observations from over 40 volunteer and patient studies, spiral balanced SSFP imaging shows significantly improved contrast compared to spiral gradient-spoiled imaging, producing better visualization of cardiac function, improved localization, and reduced flow artifacts from blood.
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Affiliation(s)
- Krishna S Nayak
- Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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23
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Kobayashi H, Kawamoto S, Brechbiel MW, Jo SK, Hu X, Yang T, Diwan BA, Waldmann TA, Schnermann J, Choyke PL, Star RA. Micro-MRI methods to detect renal cysts in mice. Kidney Int 2004; 65:1511-6. [PMID: 15086495 DOI: 10.1111/j.1523-1755.2004.00532.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mouse models of disease, especially using transgenic and knockout technologies, are powerful tools to analyze the molecular basis of disease. We recently reported that a new dynamic micro-MRI method with dendrimer-based contrast agents can visualize renal structure and function in normal living mice and mice with acute renal failure. While MRI contrast enhancement is useful for detecting functional impairment of the kidneys, this technology has limitations in assessing morphologic changes, particularly cystic disease, because contrast-enhanced micro-MRI depicts cysts as low-intensity areas that cannot be distinguished from fibrotic foci. METHODS In the current study, we evaluated if micro-MRI employing a new three-dimensional MR hydrography signal sequence [three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA)] can visualize chronic cystic changes without any contrast agents. RESULTS We were able to positively depict multiple renal cortical cysts of approximately 0.2 mm diameter in a mouse model of sickle cell disease and observe serial changes of renal cysts (>0.2 mm diameter) in cyclooxygenase-2 (COX-2) knockout mice during a 21/2-month period. Some cysts decreased in size over time. CONCLUSIONS Micro-MRI with 3D-FIESTA can depict cyst formation in the diseased kidneys of living mice without injection of contrast agents.
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Affiliation(s)
- Hisataka Kobayashi
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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24
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Abstract
Balanced steady-state free precession (SSFP) techniques provide excellent contrast between myocardium and blood at a high signal-to-noise ratio (SNR). Hence, SSFP imaging has become the method of choice for assessing cardiac function at 1.5T. The expected improvement in SNR at higher field strength prompted us to implement SSFP at 3.0T. In this work, an optimized sequence protocol for cardiac SSFP imaging at 3.0T is derived, taking into account several partly adverse effects at higher field, such as increased field inhomogeneities, longer T(1), and power deposition limitations. SSFP contrast is established by optimizing the maximum amplitude of the radiofrequency (RF) field strength for shortest TR, as well as by localized linear or second-order shimming and local optimization of the resonance frequency. Given the increased SNR, sensitivity encoding (SENSE) can be employed to shorten breath-hold times. Short-axis, long-axis, and four-chamber cine views obtained in healthy adult subjects are presented, and three different types of artifacts are discussed along with potential methods for reducing them.
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Affiliation(s)
- Michael Schär
- Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland
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25
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Scheffler K. Fast frequency mapping with balanced SSFP: Theory and application to proton-resonance frequency shift thermometry. Magn Reson Med 2004; 51:1205-11. [PMID: 15170841 DOI: 10.1002/mrm.20081] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A method is presented for the rapid acquisition of frequency maps based on multiecho balanced steady-state free precession (balanced SSFP, fast imaging with steady precession (True FISP), fast imaging employing steady-state excitation (FIESTA), or balanced fast field echo (FFE)). This technique was applied to measure temperature changes within a gel phantom based on the temperature-sensitive water proton-resonance frequency. The frequency was determined as the slope of a linear fit of the phases measured at different TEs along the echo train. The signal-to-noise ratio (SNR) of multiecho SSFP was analyzed for different parameters, such as relaxation times and flip angle, as well as for different local field inhomogeneities. The theoretical and experimental results were compared with results from the established multiecho fast low-angle shot (FLASH) method. Depending on the given tissue parameters, a significant increase in the accuracy of the frequency/temperature shift estimation compared to FLASH was observed. Furthermore, balanced SSFP can be used with very short TRs without generating a saturation-related signal loss, which is essential for real-time temperature mapping.
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Affiliation(s)
- Klaus Scheffler
- MR Physics, Department of Medical Radiology, University Hospital of Basel, Basel, Switzerland.
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Castillo E, Lima JAC, Bluemke DA. Regional myocardial function: advances in MR imaging and analysis. Radiographics 2003; 23 Spec No:S127-40. [PMID: 14557507 DOI: 10.1148/rg.23si035512] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cardiovascular magnetic resonance (MR) imaging can provide three-dimensional analysis of global and regional cardiac function with great accuracy and reproducibility. Quantitative assessment of regional function with cardiac MR imaging previously was limited by long acquisition times and time-consuming analysis. The use of steady-state free precession cine MR imaging substantially improves assessment of myocardial wall motion. Advances in gradient technology and reconstruction techniques have increased MR image acquisition speed and made real-time cine MR imaging possible. Myocardial deformation may be measured with cine MR tagging, and interpretation of the resultant tagged MR images by means of harmonic phase analysis enables prompt and precise strain measurements. Velocity-encoded and stimulated-echo techniques such as phase-contrast MR imaging and displacement encoding with stimulated echoes, or DENSE, provide high-resolution strain maps. Clinical validation of these strain imaging techniques will depend on future assessments of their effect on the management of cardiac disease.
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Affiliation(s)
- Ernesto Castillo
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, MRI-143 Nelson Basement, 600 N Wolfe St, Baltimore, MD 21287-0845, USA.
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Hargreaves BA, Vasanawala SS, Nayak KS, Hu BS, Nishimura DG. Fat-suppressed steady-state free precession imaging using phase detection. Magn Reson Med 2003; 50:210-3. [PMID: 12815698 DOI: 10.1002/mrm.10488] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fully refocused steady-state free precession (SSFP) is a rapid, efficient imaging sequence that can provide diagnostically useful image contrast. In SSFP, the signal is refocused midway between excitation pulses, much like in a spin-echo experiment. However, in SSFP, the phase of the refocused spins alternates for each resonant frequency interval equal to the reciprocal of the sequence repetition time (TR). Appropriate selection of the TR results in a 180 degrees phase difference between lipid and water signals. This phase difference can be used for fat-water separation in SSFP without any increase in scan time. The technique is shown to produce excellent non-contrast-enhanced, flow-independent angiograms of the peripheral vasculature.
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Affiliation(s)
- Brian A Hargreaves
- Department of Electrical Engineering, Stanford University, Stanford, California 94305-9510, USA.
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