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Tsampasian V, Cameron D, Sobhan R, Bazoukis G, Vassiliou VS. Phosphorus Magnetic Resonance Spectroscopy ( 31P MRS) and Cardiovascular Disease: The Importance of Energy. Medicina (B Aires) 2023; 59:medicina59010174. [PMID: 36676798 PMCID: PMC9866867 DOI: 10.3390/medicina59010174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
Background and Objectives: The heart is the organ with the highest metabolic demand in the body, and it relies on high ATP turnover and efficient energy substrate utilisation in order to function normally. The derangement of myocardial energetics may lead to abnormalities in cardiac metabolism, which herald the symptoms of heart failure (HF). In addition, phosphorus magnetic resonance spectroscopy (31P MRS) is the only available non-invasive method that allows clinicians and researchers to evaluate the myocardial metabolic state in vivo. This review summarises the importance of myocardial energetics and provides a systematic review of all the available research studies utilising 31P MRS to evaluate patients with a range of cardiac pathologies. Materials and Methods: We have performed a systematic review of all available studies that used 31P MRS for the investigation of myocardial energetics in cardiovascular disease. Results: A systematic search of the Medline database, the Cochrane library, and Web of Science yielded 1092 results, out of which 62 studies were included in the systematic review. The 31P MRS has been used in numerous studies and has demonstrated that impaired myocardial energetics is often the beginning of pathological processes in several cardiac pathologies. Conclusions: The 31P MRS has become a valuable tool in the understanding of myocardial metabolic changes and their impact on the diagnosis, risk stratification, and prognosis of patients with cardiovascular diseases.
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Affiliation(s)
- Vasiliki Tsampasian
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
- Correspondence: (V.T.); (V.S.V.)
| | - Donnie Cameron
- C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Centre, 2333 ZA Leiden, The Netherlands
| | - Rashed Sobhan
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
| | - George Bazoukis
- Department of Cardiology, Larnaca General Hospital, Larnaca 6301, Cyprus
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia 2417, Cyprus
| | - Vassilios S. Vassiliou
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
- Correspondence: (V.T.); (V.S.V.)
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High-resolution respirometry in human endomyocardial biopsies shows reduced ventricular oxidative capacity related to heart failure. Exp Mol Med 2019; 51:1-10. [PMID: 30765687 PMCID: PMC6376010 DOI: 10.1038/s12276-019-0214-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 08/17/2018] [Accepted: 10/01/2018] [Indexed: 02/07/2023] Open
Abstract
The lifetime risk of developing heart failure is approximately 20%, and survival rates remain poor. Myocardial mitochondrial function has been suggested to play a pivotal role in heart failure pathophysiology. Human studies on ex vivo mitochondrial function have mostly been limited to atrial tissue obtained during open heart surgery and have provided contradictory results. This study aimed at measuring myocardial mitochondrial function in transcatheter ventricular endomyocardial biopsies and assessing the relationship between oxidative capacity and heart function. We enrolled 40 heart failure patients undergoing ventricular assist device surgery or heart transplantation (34 males, age 57 ± 11 years, body mass index 26.6 ± 4.8 kg/m2) and 29 heart transplant recipients of comparable age and body mass index with normal left ventricular function undergoing surveillance biopsies (23 males, 57 ± 12 years, body mass index 26.2 ± 4.1 kg/m2). High-resolution respirometry was established in the myocardium to measure oxidative capacity ex vivo. The mitochondrial oxidative capacity was 90% higher in ventricular compared to atrial tissues (n = 11, p < 0.01) of explanted hearts. Respiration rates were comparable in ventricular samples of heart failure patients obtained during open heart surgery by standard tissue preparation or ex vivo endomyocardial biopsy (r = 0.9988, p < 0.0001, n = 8), and the mitochondrial oxidative capacity in samples from these patients remained stable for 8 h when stored in either of two common preservation buffers. The oxidative capacity was 44% lower in heart failure than in transplant recipients (67 ± 3 vs. 97 ± 5 pmol/[s mg], p < 0.0001) and correlated positively with heart function (r = 0.49, p < 0.01). High-resolution respirometry of ventricular tissue is feasible in transcatheter biopsies, facilitating clinical studies on myocardial mitochondrial function in patients not undergoing heart surgery. The capacity of mitochondria in heart muscle cells to use oxygen to produce energy correlates with cardiac function. Julia Szendroedi at Heinrich-Heine University, Düsseldorf, Germany, and colleagues have established a technique to reliably evaluate mitochondrial energy metabolism in patients with or recovering from heart failure. They showed that the mitochondrial oxidative capacity of cells in the lower heart chambers (ventricles) was significantly higher than in the upper heart chambers (atria). Moreover, they found that mitochondrial oxidative capacity was reduced by 44% in heart muscle biopsies from patients with heart failure compared with biopsies from heart transplant recipients with normal ventricular function. Stimulating the respiration rate of mitochondria in ventricular heart cells could be a promising strategy for improving cardiac function.
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Brown DA, Perry JB, Allen ME, Sabbah HN, Stauffer BL, Shaikh SR, Cleland JGF, Colucci WS, Butler J, Voors AA, Anker SD, Pitt B, Pieske B, Filippatos G, Greene SJ, Gheorghiade M. Expert consensus document: Mitochondrial function as a therapeutic target in heart failure. Nat Rev Cardiol 2016; 14:238-250. [PMID: 28004807 PMCID: PMC5350035 DOI: 10.1038/nrcardio.2016.203] [Citation(s) in RCA: 477] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Heart failure is a pressing worldwide public-health problem with millions of patients having worsening heart failure. Despite all the available therapies, the condition carries a very poor prognosis. Existing therapies provide symptomatic and clinical benefit, but do not fully address molecular abnormalities that occur in cardiomyocytes. This shortcoming is particularly important given that most patients with heart failure have viable dysfunctional myocardium, in which an improvement or normalization of function might be possible. Although the pathophysiology of heart failure is complex, mitochondrial dysfunction seems to be an important target for therapy to improve cardiac function directly. Mitochondrial abnormalities include impaired mitochondrial electron transport chain activity, increased formation of reactive oxygen species, shifted metabolic substrate utilization, aberrant mitochondrial dynamics, and altered ion homeostasis. In this Consensus Statement, insights into the mechanisms of mitochondrial dysfunction in heart failure are presented, along with an overview of emerging treatments with the potential to improve the function of the failing heart by targeting mitochondria.
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Affiliation(s)
- David A Brown
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, 1035 Integrated Life Sciences Building, 1981 Kraft Drive, Blacksburg, Virginia 24060, USA
| | - Justin B Perry
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, 1035 Integrated Life Sciences Building, 1981 Kraft Drive, Blacksburg, Virginia 24060, USA
| | - Mitchell E Allen
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, 1035 Integrated Life Sciences Building, 1981 Kraft Drive, Blacksburg, Virginia 24060, USA
| | - Hani N Sabbah
- Division of Cardiovascular Medicine, Department of Medicine, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, Michigan 48202, USA
| | - Brian L Stauffer
- Division of Cardiology, Department of Medicine, University of Colorado Denver, 12700 East 19th Avenue, B139, Aurora, Colorado 80045, USA
| | - Saame Raza Shaikh
- Department of Biochemistry and Molecular Biology, East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, 115 Heart Drive, Greenville, North Carolina 27834, USA
| | - John G F Cleland
- National Heart &Lung Institute, National Institute of Health Research Cardiovascular Biomedical Research Unit, Royal Brompton &Harefield Hospitals, Imperial College, London, UK
| | - Wilson S Colucci
- Cardiovascular Medicine Section, Boston University School of Medicine and Boston Medical Center, 88 East Newton Street, C-8, Boston, Massachusetts 02118, USA
| | - Javed Butler
- Division of Cardiology, Health Sciences Center, T-16 Room 080, SUNY at Stony Brook, New York 11794, USA
| | - Adriaan A Voors
- University of Groningen, Department of Cardiology, University Medical Center Groningen, Groningen 9713 GZ, Netherlands
| | - Stefan D Anker
- Department of Innovative Clinical Trials, University Medical Centre Göttingen (UMG), Robert-Koch-Straße, D-37075, Göttingen, Germany
| | - Bertram Pitt
- University of Michigan School of Medicine, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109, USA
| | - Burkert Pieske
- Department of Cardiology, Charité University Medicine, Campus Virchow Klinikum, and German Heart Center Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Gerasimos Filippatos
- National and Kopodistrian University of Athens, School of Medicine, Heart Failure Unit, Department of Cardiology, Athens University Hospital Attikon, Rimini 1, Athens 12462, Greece
| | - Stephen J Greene
- Division of Cardiology, Duke University Medical Center, 2301 Erwin Road Suite 7400, Durham, North Carolina 27705, USA
| | - Mihai Gheorghiade
- Center for Cardiovascular Innovation, Northwestern University Feinberg School of Medicine, 201 East Huron, Galter 3-150, Chicago, Illinois 60611, USA
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Chesser AM, Harwood SM, Raftery MJ, Yaqoob MM. Myocardial bioenergetic abnormalities in experimental uremia. Int J Nephrol Renovasc Dis 2016; 9:129-37. [PMID: 27307758 PMCID: PMC4888764 DOI: 10.2147/ijnrd.s89926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Cardiac bioenergetics are known to be abnormal in experimental uremia as exemplified by a reduced phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio. However, the progression of these bioenergetic changes during the development of uremia still requires further study and was therefore investigated at baseline, 4 weeks and 8 weeks after partial nephrectomy (PNx). Methods A two-stage PNx uremia model in male Wistar rats was used to explore in vivo cardiac and skeletal muscles’ bioenergetic changes over time. High-energy phosphate nucleotides were determined by phosphorus-31 nuclear magnetic resonance (31P-NMR) and capillary zone electrophoresis. Results 31P-NMR spectroscopy revealed lower PCr/ATP ratios in PNx hearts compared to sham (SH)-operated animals 4 weeks after PNx (median values given ± SD, 0.64±0.16 PNx, 1.13±0.31 SH, P<0.02). However, 8 weeks after PNx, the same ratio was more comparable between the two groups (0.84±0.15 PNx, 1.04±0.44 SH, P= not significant), suggestive of an adaptive mechanism. When 8-week hearts were prestressed with dobutamine, the PCr/ATP ratio was again lower in the PNx group (1.08±0.36 PNx, 1.55±0.38 SH, P<0.02), indicating a reduced energy reserve during the progression of uremic heart disease. 31P-NMR data were confirmed by capillary zone electrophoresis, and the changes in myocardial bioenergetics were replicated in the skeletal muscle. Conclusion This study provides evidence of the changes that occur in myocardial energetics in experimental uremia and highlights how skeletal muscle bioenergetics mirror those found in the cardiac tissue and so might potentially serve as a practical surrogate tissue during clinical cardiac NMR investigations.
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Affiliation(s)
- Alistair Ms Chesser
- Department of Nephrology, Barts Health NHS Trust, Royal London Hospital, Queen Mary University of London, London, UK
| | - Steven M Harwood
- Translational Medicine and Therapeutics, William Harvey Research Institute, John Vane Science Centre, Queen Mary University of London, London, UK
| | - Martin J Raftery
- Department of Nephrology, Barts Health NHS Trust, Royal London Hospital, Queen Mary University of London, London, UK
| | - Muhammad M Yaqoob
- Department of Nephrology, Barts Health NHS Trust, Royal London Hospital, Queen Mary University of London, London, UK; Translational Medicine and Therapeutics, William Harvey Research Institute, John Vane Science Centre, Queen Mary University of London, London, UK
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van Ewijk PA, Schrauwen-Hinderling VB, Bekkers SCAM, Glatz JFC, Wildberger JE, Kooi ME. MRS: a noninvasive window into cardiac metabolism. NMR IN BIOMEDICINE 2015; 28:747-66. [PMID: 26010681 DOI: 10.1002/nbm.3320] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/02/2015] [Accepted: 04/07/2015] [Indexed: 05/21/2023]
Abstract
A well-functioning heart requires a constant supply of a balanced mixture of nutrients to be used for the production of adequate amounts of adenosine triphosphate, which is the main energy source for most cellular functions. Defects in cardiac energy metabolism are linked to several myocardial disorders. MRS can be used to study in vivo changes in cardiac metabolism noninvasively. MR techniques allow repeated measurements, so that disease progression and the response to treatment or to a lifestyle intervention can be monitored. It has also been shown that MRS can predict clinical heart failure and death. This article focuses on in vivo MRS to assess cardiac metabolism in humans and experimental animals, as experimental animals are often used to investigate the mechanisms underlying the development of metabolic diseases. Various MR techniques, such as cardiac (31) P-MRS, (1) H-MRS, hyperpolarized (13) C-MRS and Dixon MRI, are described. A short overview of current and emerging applications is given. Cardiac MRS is a promising technique for the investigation of the relationship between cardiac metabolism and cardiac disease. However, further optimization of scan time and signal-to-noise ratio is required before broad clinical application. In this respect, the ongoing development of advanced shimming algorithms, radiofrequency pulses, pulse sequences, (multichannel) detection coils, the use of hyperpolarized nuclei and scanning at higher magnetic field strengths offer future perspective for clinical applications of MRS.
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Affiliation(s)
- Petronella A van Ewijk
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | - Vera B Schrauwen-Hinderling
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | | | - Jan F C Glatz
- Maastricht University Medical Center, Molecular Genetics, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
| | | | - M Eline Kooi
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
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Abstract
31-phosphorous ((31)P) magnetic resonance spectroscopy (MRS) is a technique that allows the noninvasive characterization of the biochemical and metabolic state of the myocardium in vivo. MRS is a pure form of molecular imaging using magnetic resonance signals from nuclei with nuclear spin to assess cardiac metabolism without the need for external radioactive tracers. (31)P MRS provides information on the underlying metabolic abnormalities that are fundamental to common conditions including ischemic heart disease, cardiomyopathy, hypertrophy and valvular disease. (31)P MRS could potentially also have a role to play in assessing response to therapy as well as the effectiveness of metabolic modulating agents. However, the use of MRS is currently limited to research due to its poor reproducibility, low spatial and temporal resolution, and long acquisition times. With technical advances in both the spectrometers and postprocessing, MRS is likely to play a role in the future of multimodal noninvasive cardiac assessment.
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Affiliation(s)
- Roger Beadle
- University of Aberdeen, Fosterhill, Aberdeen, AB25 2ZD, UK.
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Burkhard T, Herzog C, Linzbach S, Spyridopoulos I, Huebner F, Vogl TJ. Cardiac 31P-MRS compared to echocardiographic findings in patients with hypertensive heart disease without overt systolic dysfunction—Preliminary results. Eur J Radiol 2009; 71:69-74. [DOI: 10.1016/j.ejrad.2008.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 03/11/2008] [Accepted: 03/12/2008] [Indexed: 10/22/2022]
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Abstract
Magnetic resonance spectroscopy (MRS) allows for the non-invasive detection of a wide variety of metabolites in the heart. To study the metabolic changes that occur in heart failure, (31)P- and (1)H-MRS have been applied in both patients and experimental animal studies. (31)P-MRS allows for the detection of phosphocreatine (PCr), ATP, inorganic phosphate (Pi) and intracellular pH, while (1)H-MRS allows for the detection of total creatine. All these compounds are involved in the regulation of the available energy from ATP hydrolysis via the creatine kinase (CK) reaction. Using cardiac MRS, it has been found that the PCr/CK system is impaired in the failing heart. In both, patients and experimental models, PCr levels as well as total creatine levels are reduced, and in severe heart failure ATP is also reduced. PCr/ATP ratios correlate with the clinical severity of heart failure and, importantly, are a prognostic indicator of mortality in patients. In addition, the chemical flux through the CK reaction, measured with (31)P saturation transfer MRS, is reduced more than the steady-state levels of high-energy phosphates in failing myocardium in both experimental models and in patients. Experimental studies suggest that these changes can result in increased free ADP levels when the failing heart is stressed. Increased free ADP levels, in turn, result in a reduction in the available free energy of ATP hydrolysis, which may directly contribute to contractile dysfunction. Data from transgenic mouse models also suggest that an intact creatine/CK system is critical for situations of cardiac stress.
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Affiliation(s)
- Michiel Ten Hove
- Department of Cardiovascular Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.
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Abstract
Studies have shown that hypertrophied hearts are unusually vulnerable to ischemia. Compromised O2supply has been postulated as a possible explanation for this phenomenon on the basis of elongated O2diffusion distance and altered coronary vasculature found in hypertrophied myocardium. To examine the postulate, perfused heart experiments followed the metabolic and functional responses of hypertrophic myocardium to ischemia.1H/31P NMR was used to measure cellular oxygenation and energy level during ischemia-reperfusion. The left ventricles from spontaneously hypertensive rats (SHR) were enlarged by 48%. With this moderate degree of hypertrophy, cellular O2and energy levels were normal during baseline perfusion. After an ischemic episode, however, cellular O2was severely deprived in the SHR hearts compared with the normal hearts. Depressed postischemic O2reperfusion correlated well with depressed energetic and functional recovery. The results from the current study thus demonstrate a critical relationship between reperfused O2level and functional recovery in hypertrophic myocardium. The role of reperfused O2, however, is time dependent. During early reperfusion, factor(s) other than O2appear to limit functional recovery. It is when the mechanical function of the heart approaches a new steady state that O2becomes a dominant factor. Meanwhile, the finding of a normal O2level in preischemic SHR hearts defies the notion of preexisting hypoxia as a primer of ischemic damage.
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Affiliation(s)
- Youngran Chung
- Biochemistry and Molecular Medicine, University of California, Davis, CA 95616-8635, USA.
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Hansch A, Rzanny R, Heyne JP, Leder U, Reichenbach JR, Kaiser WA. Noninvasive measurements of cardiac high-energy phosphate metabolites in dilated cardiomyopathy by using 31P spectroscopic chemical shift imaging. Eur Radiol 2005; 15:319-23. [PMID: 15630572 DOI: 10.1007/s00330-004-2504-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 08/20/2004] [Accepted: 08/27/2004] [Indexed: 11/21/2022]
Abstract
Dilated cardiomyopathy (DCM) is accompanied by an impaired cardiac energy metabolism. The aim of this study was to investigate metabolic ratios in patients with DCM compared to controls by using spectroscopic two-dimensional chemical shift imaging (2D-CSI). Twenty volunteers and 15 patients with severe symptoms (left ventricular ejection fraction, LVEF<30%) and ten patients with moderate symptoms (LVEF>30%) of DCM were investigated. Cardiac 31P MR 2D-CSI measurements (voxel size: 40x40x100 mm3) were performed with a 1.5 T whole-body scanner. Measurement time ranged from 15 min to 30 min. Peak areas and ratios of different metabolites were evaluated, including high-energy phosphates (PCr, ATP), 2,3-diphosphoglycerate (2,3-DPG) and phosphodiesters (PDE). In addition, we evaluated how PCr/ATP ratios correlate with LVEF as an established prognostic factor of heart failure. The PCr/gamma-ATP ratio was significantly decreased in patients with moderate and severe DCM and showed a linear correlation with reduced LVEFs. PDE/ATP ratios were significantly increased only in patients with severe DCM as compared to volunteers. Applying 31P MRS with commonly-available 2D-CSI sequences is a valuable technique to evaluate DCM by determining PCr/ATP ratios noninvasively. In addition to reduced PCr/ATP ratios observed in patients suffering from DCM, significantly-increased PDE/ATP ratios were found in patients with severe DCM.
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Affiliation(s)
- A Hansch
- Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University Jena, Erlanger Allee 101, 07747, Jena, Germany.
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Pohmann R, von Kienlin M. Accurate phosphorus metabolite images of the human heart by 3D acquisition-weighted CSI. Magn Reson Med 2001; 45:817-26. [PMID: 11323808 DOI: 10.1002/mrm.1110] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fourier imaging modalities suffer from significant signal contamination between adjacent voxels, especially when the spatial resolution is comparable to the size of the anatomical structures. This contamination can be positive or negative, depending on the spatial response function and the geometry of the object. Such a situation arises in human cardiac (31)P chemical shift imaging (CSI). Acquisition-weighted CSI reduces this contamination substantially, which is demonstrated by comparing conventional CSI to Hanning-weighted 3D (31)P-CSI experiments in 13 healthy volunteers at 2 T. The nominal spatial resolution and the total number of scans were identical for both experiments. The improved spatial response function of the acquisition-weighted experiment led to a significantly (P < 0.0001) higher myocardial PCr/ATP ratio (2.05 +/- 0.31, mean +/- SD, N = 33, corrected for saturation and blood contribution) compared to the conventional CSI experiment (1.60 +/- 0.46). This is explained by the absence of negative contamination from skeletal muscle, which also resulted in an increase of the observed SNR (from 5.4 +/- 1.4 to 7.2 +/- 1.4 for ATP). With acquisition-weighted CSI, metabolic images with a nominal resolution of 16 ml could be obtained in a measurement time of 30 min. After correction for the inhomogeneous B(1) field of the surface coil, these images show uniform ATP distribution in the entire myocardium, including the posterior wall.
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Affiliation(s)
- R Pohmann
- Department of Biophysics, University of Würzburg, Würzburg, Germany
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13
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Abstract
The goal of this review is to present a comprehensive survey of the many intriguing facets of creatine (Cr) and creatinine metabolism, encompassing the pathways and regulation of Cr biosynthesis and degradation, species and tissue distribution of the enzymes and metabolites involved, and of the inherent implications for physiology and human pathology. Very recently, a series of new discoveries have been made that are bound to have distinguished implications for bioenergetics, physiology, human pathology, and clinical diagnosis and that suggest that deregulation of the creatine kinase (CK) system is associated with a variety of diseases. Disturbances of the CK system have been observed in muscle, brain, cardiac, and renal diseases as well as in cancer. On the other hand, Cr and Cr analogs such as cyclocreatine were found to have antitumor, antiviral, and antidiabetic effects and to protect tissues from hypoxic, ischemic, neurodegenerative, or muscle damage. Oral Cr ingestion is used in sports as an ergogenic aid, and some data suggest that Cr and creatinine may be precursors of food mutagens and uremic toxins. These findings are discussed in depth, the interrelationships are outlined, and all is put into a broader context to provide a more detailed understanding of the biological functions of Cr and of the CK system.
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Affiliation(s)
- M Wyss
- F. Hoffmann-La Roche, Vitamins and Fine Chemicals Division, Basel, Switzerland.
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Jung WI, Dietze GJ. 31P nuclear magnetic resonance spectroscopy: a noninvasive tool to monitor metabolic abnormalities in left ventricular hypertrophy in human. Am J Cardiol 1999; 83:19H-24H. [PMID: 10750582 DOI: 10.1016/s0002-9149(99)00252-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
31p nuclear magnetic resonance (NMR) spectroscopy represents a unique instrument to noninvasively monitor myocardial metabolism in humans. The technique has been used to study the metabolism in myocardial hypertrophy in humans with hypertension, aortic stenosis, aortic incompetence, mitral regurgitation, and hypertrophic cardiomyopathy, as well as after maintenance dialysis or long-term physical exercise in elite cyclists. A primary aim is the determination of the phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio, which reflects the energetic state of the myocardium. Recent investigations take advantage of proton decoupling in 31p NMR spectroscopy, which, besides the PCr/ATP ratio, also allows the determination of the inorganic phosphate/ PCr and the phosphomonoester/PCr ratios as additional indicators for alterations in myocardial metabolism. Abnormal myocardial metabolism was found in humans with aortic stenosis, mitral regurgitation, hypertrophic cardiomyopathy, and in patients who undergo maintenance dialysis. A trend toward a lower PCr/ATP ratio was reported in hypertension and aortic incompetence patients. Several studies have revealed a dependence of the metabolic abnormalities on the degree of heart failure, and one study claimed that a correlation with the extent of hypertrophy exists. No metabolic abnormalities were found in elite cyclists.
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Affiliation(s)
- W I Jung
- Hypertension and Diabetes Research Unit, Max Grundig Clinic, Bühl, Germany
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15
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Abstract
This article takes three different approaches to the question of whether the failing heart is in an energy-starved state. A brief historical overview introduces the issue and points out problems in both models and methods. Second, current information regarding the energetic state of the failing heart is examined. Finally, the mechanistic and therapeutic implications of a defect in energy production are described.
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Affiliation(s)
- A M Katz
- Department of Medicine, University of Connecticut School of Medicine, Farmington, USA.
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Löffler R, Sauter R, Kolem H, Haase A, von Kienlin M. Localized spectroscopy from anatomically matched compartments: improved sensitivity and localization for cardiac 31P MRS in humans. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 134:287-299. [PMID: 9761704 DOI: 10.1006/jmre.1998.1497] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Several pioneering studies have demonstrated that localized 31P NMR spectroscopy of the human heart might become an important diagnostic tool in cardiology. The main limitation is due to the low sensitivity of these experiments, allowing only crude spatial resolution. We have implemented a three-dimensional version of SLOOP ("spectral localization with optimal pointspread function") on a clinical instrument. SLOOP takes advantage of all available a priori information to match the size and the shape of the sensitive volumes to the anatomical structures in the examined subject. Thus, SLOOP reduces the contamination from adjacent organs and improves the sensitivity compared to conventional techniques such as ISIS or chemical shift imaging (CSI). Initial studies were performed on six healthy volunteers at 1.5 T. The good localization properties are demonstrated by the absence of resonances from blood in the heart spectra, and by PCr-free spectra from the liver. Compared to conventional CSI, the signal-to-noise ratio of the SLOOP heart spectra was improved by approximately 30%. Taking into account the varying excitation angle in the inhomogeneous B1 field of the surface coil, the SLOOP model computes the local spin saturation at every point in space. Therefore, no global saturation correction is required in the quantitative evaluation of local spectra. In this study, we found a PCr/gamma-ATP ratio in the left ventricular wall of 1.90 +/- 0.33 (mean +/- standard deviation).
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Affiliation(s)
- R Löffler
- Physikalisches Institut, Universität Würzburg, Würzburg, Germany
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Jung WI, Sieverding L, Breuer J, Schmidt O, Widmaier S, Bunse M, van Erckelens F, Apitz J, Dietze GJ, Lutz O. Detection of phosphomonoester signals in proton-decoupled 31P NMR spectra of the myocardium of patients with myocardial hypertrophy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 133:232-235. [PMID: 9654494 DOI: 10.1006/jmre.1998.1454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Proton-decoupled 31P NMR spectroscopy at 1.5 T of the anterior left ventricular myocardium was used to monitor myocardial phosphate metabolism in asymptomatic patients with hypertrophic cardiomyopathy (HCM, n = 14) and aortic stenosis (AS, n = 12). In addition to the well-known phosphorus signals a phosphomonoester (PME) signal was detected at about 6.9 ppm in 7 HCM and 2 AS patients. This signal was not observed in the spectra of normal controls (n = 11). We suggest that in spectra of patients with myocardial hypertrophy the presence of a PME signal reflects alterations in myocardial glucose metabolism.
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Affiliation(s)
- W I Jung
- Physikalisches Institut, University of Tübingen, Tübingen, 72076, Germany
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Jung WI, Sieverding L, Breuer J, Hoess T, Widmaier S, Schmidt O, Bunse M, van Erckelens F, Apitz J, Lutz O, Dietze GJ. 31P NMR spectroscopy detects metabolic abnormalities in asymptomatic patients with hypertrophic cardiomyopathy. Circulation 1998; 97:2536-42. [PMID: 9657474 DOI: 10.1161/01.cir.97.25.2536] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) often causes sudden, unexpected death in adolescents and young adults. Alterations in myocardial metabolism are considered to be causes for contractile dysfunction. We examined the question of whether metabolic abnormalities antedate the manifestation of symptoms in patients with HCM. METHODS AND RESULTS Proton-decoupled 31P NMR spectroscopy of the anterior left ventricular wall of the heart of 14 young, asymptomatic patients with HCM was performed with a 1.5-T whole-body imager. Spectra of the phosphate metabolites were compared with those of normal control subjects. The patients exhibited a significantly reduced (P<0.02) ratio of phosphocreatine (PCr) to ATP of 1.98+/-0.37 (mean+/-SD), compared with 2.46+/-0.53 obtained in 11 normal control subjects. In addition, the group of patients with severe hypertrophy of the interventricular septum (n=8) showed a significantly increased (P<0.05) Pi-to-PCr ratio, with a Pi x 100/PCr of 20.0+/-8.3 versus 9.7+/-7.2 in control subjects. Both abnormalities are similar to those found in ischemic myocardium. This view is also supported by a significantly increased (P<0.01) phosphomonoester (PME)-to-PCr ratio, with a PME x 100/PCr of 20.7+/-11.2 compared with 8.4+/-6.7 in control subjects, indicating altered glucose metabolism. CONCLUSIONS 31P NMR spectroscopy detects alterations of myocardial metabolism in asymptomatic patients with HCM. These alterations may contribute to the understanding of the pathophysiology and natural history of the disease.
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Affiliation(s)
- W I Jung
- Hypertension and Diabetes Research Unit, Max Grundig Clinic, Bühl, Germany
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Neubauer S, Horn M, Cramer M, Harre K, Newell JB, Peters W, Pabst T, Ertl G, Hahn D, Ingwall JS, Kochsiek K. Myocardial phosphocreatine-to-ATP ratio is a predictor of mortality in patients with dilated cardiomyopathy. Circulation 1997; 96:2190-6. [PMID: 9337189 DOI: 10.1161/01.cir.96.7.2190] [Citation(s) in RCA: 469] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND In patients with heart failure due to dilated cardiomyopathy, cardiac energy metabolism is impaired, as indicated by a reduction of the myocardial phosphocreatine-to-ATP ratio, measured noninvasively by 31P-MR spectroscopy. The purpose of this study was to test whether the phosphocreatine-to-ATP ratio also offers prognostic information in terms of mortality prediction as well as how this index compares with well-known mortality predictors such as left ventricular ejection fraction (LVEF) or New York Heart Association (NYHA) class. METHODS AND RESULTS Thirty-nine patients with dilated cardiomyopathy were followed up for 928+/-85 days (2.5 years). At study entry, LVEF and NYHA class were determined, and the cardiac phosphocreatine-to-ATP ratio was measured by localized 31P-MR spectroscopy of the anterior myocardium. During the study period, total mortality was 26%. Patients were divided into two groups, one with a normal phosphocreatine-to-ATP ratio (>1.60; mean+/-SE, 1.98+/-0.07; n=19; healthy volunteers: 1.94+/-0.11, n=30) and one with a reduced phosphocreatine-to-ATP ratio (<1.60; 1.30+/-0.05; n=20). At re-evaluation (mean, 2.5 years), 8 of 20 patients with reduced phosphocreatine-to-ATP ratios had died, all of cardiovascular causes (total and cardiovascular mortality, 40%). Of the 19 patients with normal phosphocreatine-to-ATP ratios, 2 had died (total mortality, 11%), one of cardiovascular causes (cardiovascular mortality, 5%). Kaplan-Meier analysis showed significantly reduced total (P=.036) and cardiovascular (P=.016) mortality for patients with normal versus patients with low phosphocreatine-to-ATP ratios. A Cox model for multivariate analysis showed that the phosphocreatine-to-ATP ratio and NYHA class offered significant independent prognostic information on cardiovascular mortality. CONCLUSIONS The myocardial phosphocreatine-to-ATP ratio, measured noninvasively with 31P-MR spectroscopy, is a predictor of both total and cardiovascular mortality in patients with dilated cardiomyopathy.
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Affiliation(s)
- S Neubauer
- Department of Medicine, Würzburg University, Germany.
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Carrasco HA, Alarcon M, Olmos L, Burguera J, Burguera M, Dipaolo A, Carrasco HR. Biochemical characterization of myocardial damage in chronic Chagas' disease. Clin Cardiol 1997; 20:865-9. [PMID: 9377823 PMCID: PMC6655757 DOI: 10.1002/clc.4960201013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/1997] [Accepted: 07/18/1997] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In the early asymptomatic stages of cardiomyopathy in chronic Chagas' disease, septal endomyocardial biopsies disclose multiple evidence of evolving myocardial damage. Detection of signs of an active myocardiopathic process may allow a better understanding of the evolution of this and other related dilated cardiomyopathies and provide a means for evaluation of the result of future therapeutic schemes. HYPOTHESIS This study was designed to explore whether cellular damage caused by Chagas' disease is reflected by changes of certain serum electrolytes, enzymes, and glycoproteins associated with myocardial metabolism, especially in the coronary sinus into which the blood just metabolized by the heart is drained. METHODS The study included 47 patients (35 men and 12 women, average age 40 years) with positive complement fixation reaction and hemagglutination test for Chagas' disease. The study protocol included medical records, electrocardiographic (ECG) recordings, routine laboratory analysis, chest x-rays, noninvasive cardiac examinations, and cardiac catheterization. RESULTS In this study, we determined the concentration or activity of 9 electrolytes, 5 glycoprotein fractions, and 12 enzymes related to cardiac metabolism in blood from the coronary sinus, the superior vena cava, the pulmonary and femoral arteries, and found early release of inorganic phosphorus (p < 0.01) and isocitrate dehydrogenase (p < 0.01) from the heart and increased activity of serum alkaline phosphatase and aldolase (p < 0.05). Discriminant analysis suggested that the combination of the clinical picture, electrocardiographic findings, and peripheral activity of serum aldolase might be useful for the recognition of 86% of patients with Chagas' disease without segmental myocardial damage, 80% of those with early segmental abnormalities, and all patients with advanced myocardial damage or congestive heart failure. CONCLUSION These results would make the application of more invasive techniques, such as left cineventriculography for detection of early myocardial compromise, unnecessary.
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Affiliation(s)
- H A Carrasco
- Cardiovascular Center, Faculty of Medicine, University of los Andes, Mérida, Venezuela
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Abstract
Although
in vivo
31
P NMR permits unique measurements of the body’s stores of high energy phosphate metabolites, their low concentrations place critical limits and demands on spatial resolution, localization techniques, and reproducibility. We argue that optimum reliability and reproducibility of
in vivo
measurements of metabolite ratios and concentrations is best achieved by preselecting the minimal requirements for spatial localization suited to, and varying with, the particular organ and disease type. Strategies for measuring metabolite ratios and concentrations in the human heart and brain are discussed and demonstrated in the context of the expeditious choice of operating parameters, including localized volume size, localization technique, NMR coils, radiofrequency-field uniformity, patient positioning, and corrections for spectral distortion caused by NMR relaxation, to optimize the return of useful metabolic information in practical clinical research exams of about an hour duration.
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Friedrich J, Apstein CS, Ingwall JS. 31P nuclear magnetic resonance spectroscopic imaging of regions of remodeled myocardium in the infarcted rat heart. Circulation 1995; 92:3527-38. [PMID: 8521576 DOI: 10.1161/01.cir.92.12.3527] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The clinical course of a patient with a myocardial infarction (MI) depends largely on the ability of the noninfarcted region to remodel and compensate for the loss of the infarcted region. Previous studies have shown that the remaining viable myocardium remodels morphologically, functionally, and biochemically. The purpose of this study was to define the regional distribution of the biochemical remodeling that occurs after MI in rat hearts by use of a technique that could be applied noninvasively to human subjects. METHODS AND RESULTS Infarcts of the left ventricular apex and anterolateral wall were induced by occluding a coronary artery. Eight to 10 weeks after infarction, one-dimensional chemical shift imaging (CSI) was used to obtain 31P nuclear magnetic resonance (NMR) spectra of eight 2.5-mm-thick cross-sectional slices along the long axis (from base to apex) of isolated buffer-perfused rat hearts. Regional ATP and phosphocreatine (PCr) contents were compared in remodeled versus normal (sham) myocardium. Spin-echo 1H MR images identified the mass of each slice, allowing calculations of metabolite amount per unit myocardium in each slice. 1H MR images identify the hypertrophy of remodeled myocardium but do not discriminate between scar and viable tissue. In contrast, 31P CSI does distinguish viable tissue. Compared with shams, there was less 31P signal in the slices distal to the occlusion containing mainly scar tissue and increased signal intensity in slices proximal to the occlusion because of myocyte hypertrophy. The ATP signal intensity changed in direct proportion to the viable tissue mass in the slice, suggesting that the amount of ATP per unit mass in viable remodeled myocardium is the same as that of the shams. In contrast, the amount of PCr per unit mass in remodeled myocardium decreased. This decrease is uniform across the slices, correlates with infarct size, and parallels a similar decrease in tissue creatine content. CONCLUSIONS 31P CSI of post-MI hearts shows that (1) PCr decreases uniformly (ie, independent of the distance from the scar) in the noninfarcted remodeled myocardium, and its amount inversely correlates with infarct size; and (2) the ATP signal provides a profile of viable myocardium and is a biochemical marker of morphological remodeling and hypertrophy that has occurred in noninfarcted regions. Thus, 31P CSI provides both a marker that tissue injury has occurred (decreased PCr) and a marker of the extent of remodeling in response to injury (ATP distribution) in a single set of noninvasive measurements.
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Affiliation(s)
- J Friedrich
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
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Yabe T, Mitsunami K, Inubushi T, Kinoshita M. Quantitative measurements of cardiac phosphorus metabolites in coronary artery disease by 31P magnetic resonance spectroscopy. Circulation 1995; 92:15-23. [PMID: 7788910 DOI: 10.1161/01.cir.92.1.15] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND 31P metabolite measurements in the human heart by magnetic resonance spectroscopy (MRS) have been reported previously. By use of a method in which metabolite content was quantified with reference to a standard located outside the chest, it has become possible to measure the content of phosphocreatine (PCr) and ATP in vivo in the human heart. In this study, PCr and ATP contents were measured by 31P MRS and compared in human myocardium with reversible ischemia or scar diagnosed by exercise thallium scintigraphy. METHODS AND RESULTS Forty-one subjects with stenosis of the left anterior descending coronary artery (> 50%) and 11 healthy control subjects (C) composed the present study group. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+], n = 29) who demonstrated redistribution at late image and a fixed 201Tl defect group (RD[-], n = 12). While the subjects lay supine within the magnet, 31P MR spectra were obtained from the anterior and apical regions of the left ventricle by slice-selected one-dimensional chemical shift imaging. For metabolite quantification, a standard was placed at the center of the surface coil. ANOVA revealed significant differences among the three groups with respect to the mean (+/- SD) PCr at rest (C, 12.14 +/- 4.25 > RD[+], 7.64 +/- 3.00 > RD[-], 3.94 +/- 2.21 mumol/g wet heart tissue, P < .05) as well as a significant decrease in ATP in the RD(-) group (C, 7.72 +/- 2.97; RD[+], 6.35 +/- 3.17 > RD[-], 4.35 +/- 1.52 mumol/g wet heart tissue, P < .05). CONCLUSIONS Compared with healthy control subjects, PCr content decreased significantly in patients with both reversible and fixed 201Tl defects, and ATP content decreased significantly in subjects with fixed thallium defects. These results suggest that the measurement of ATP content in the human heart by 31P MRS is a clinically important method for the evaluation of myocardial viability.
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Affiliation(s)
- T Yabe
- First Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan
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Popovich M, Kostin S, Branishte T, Kobets V, Kapelko V. Cellular hypertrophy in cardiomyopathic patients is associated with lower creatine-stimulated mitochondrial respiration. Mol Cell Biochem 1995; 143:1-5. [PMID: 7776953 DOI: 10.1007/bf00925920] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The mitochondrial respiration rate and morphometric indices in endomyocardial biopsy samples were measured in 43 patients with dilated cardiomyopathy selected in accordance to WHO criteria by endomyocardial biopsy studies after excluding of various forms of myocarditis, alcoholic cardiomyopathy and other specific diseases of the heart. A group of 13 patients with unusually high mean myocyte diameter, 30 +/- 4 microns, and nuclear size, 57 +/- 5 microns, was selected. The remainder of patients (n = 30) had significantly lower mean myocyte diameter and nuclear size, 23 +/- 3 and 42 +/- 6 microns, respectively, (p < 0.01). Creatine-stimulated elevation in mitochondrial respiration rate as measured in saponin-skinned fibers was found in the former group to be much lower (36 +/- 4%) as compared with the remainder (90 +/- 12%). Also, the former group of patients had higher left ventricular enddiastolic pressure and volume index with concomitantly decreased ejection fraction. The results indicate that marked nuclear and cellular hypertrophy is associated with lower creatine-stimulated mitochondrial respiration rate and more severe cardiac failure. They suggest that disorders in energy supply to myofibrils may be related to disturbances in cellular genetic apparatus.
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Affiliation(s)
- M Popovich
- Institute of Preventive and Clinical Cardiology, Kishinev Moldova and Cardiology Research Center, Moscow, Russia
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26
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Valkema R, van Eck-Smit BL, van der Wall EE. Cardiac metabolism: a technical spectrum of modalities including positron emission tomography, single-photon emission computed tomography, and magnetic resonance spectroscopy. J Nucl Cardiol 1994; 1:546-60. [PMID: 9420749 DOI: 10.1007/bf02939978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Noninvasive techniques for the assessment of cardiac metabolism are important for the detection of potentially salvageable tissue in jeopardized areas of the myocardium. The correct identification of hibernating and stunned myocardium in patients with severely depressed cardiac function can have vital therapeutic consequences for the patient. Changes in myocardial fatty acid and glucose metabolism during acute and prolonged ischemia can be traced by positron-emitting or gamma-emitting radiopharmaceuticals. Alternatively, 31P-labeled magnetic resonance spectroscopy can be used for the assessment of high-energy phosphate metabolism. It is not yet clear which modality will emerge as the most useful in the clinical setting. Positron emission tomography (PET) that uses combinations of flow tracers and metabolic tracers offers unique opportunities for quantification and high-resolution static and rapid dynamic studies. Currently, assessment of glucose metabolism with 18F-fluorodeoxyglucose is regarded as the gold standard for myocardial viability and prediction of improvement of impaired contractile function after revascularization. However, preserved oxidative metabolism may be required for potential functional improvement, and therefore assessment of residual oxidative metabolism by 11C-labeled acetate PET may prove to be more accurate than 18F-fluorodeoxyglucose PET, which reflects both anaerobic and oxidative metabolism. Moreover, because fatty acids are metabolized only aerobically, they are excellent candidates for the clinical assessment of myocardial viability and prediction of functional improvement after revascularization. Especially derivatives of fatty acids that are not metabolized but accumulate in the myocyte are attractive for myocardial imaging. Examples are 123I-beta-methyl-p-iodophenyl pentadecanoic acid and 15-(o-123I-phenyl)-pentadecanoic acid. These tracers can be detected by planar scintigraphy and single-photon emission computed tomography, which are more economical and widely available than PET. In addition, 511 keV collimators have been developed recently, making the detection of positron emitters by planar scintigraphy and single-photon emission computed tomography feasible. The experience with 31P-labeled magnetic resonance spectroscopy in humans is still limited. With current magnetic resonance spectroscopic techniques, insufficient spatial resolution is achieved for clinical purposes, but the possibility of serial measurements to monitor rapid changes of phosphate-containing molecules in time makes magnetic resonance spectroscopy very valuable for the research of myocardial metabolism.
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Affiliation(s)
- R Valkema
- Department of Diagnostic Radiology and Nuclear Medicine, University Hospital Leiden, The Netherlands
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van Dobbenburgh JO, Lekkerkerk C, van Echteld CJ, de Beer R. Saturation correction in human cardiac 31P MR spectroscopy at 1.5 T. NMR IN BIOMEDICINE 1994; 7:218-224. [PMID: 7848811 DOI: 10.1002/nbm.1940070504] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study was conducted to verify the validity of using saturation factors obtained from unlocalized 31P spectra containing both chest wall and heart muscle signals for correcting human heart muscle phosphocreatine/beta-adenosine triphosphate (PCr/beta-ATP) ratios. Saturation factors and T1 relaxation times were determined from 31P magnetic resonance spectra of human chest wall and heart muscle simultaneously in healthy volunteers using one-dimensional spectroscopic imaging in combination with a two-dimensional ISIS sequence by using adiabatic 180 degrees inversion and adiabatic 90 degrees excitation pulses at 1.5 T. Blood corrected saturation factors for PCr/beta-ATP at a TR of 2.4 s were significantly different in heart muscle and chest wall muscle, 1.30 +/- 0.25 and 1.73 +/- 0.31, respectively (p < 0.05). T1 values for PCr and beta-ATP in heart muscle were 4.28 +/- 0.72 and 2.99 +/- 0.52 and in chest wall muscle 6.82 +/- 1.07 and 3.39 +/- 0.48, respectively. The T1(PCr)/T1(beta-ATP) ratios in chest wall and heart muscle were not identical. The mean PCr/beta-ATP ratios in heart and chest wall muscle of six healthy volunteers were 1.23 +/- 0.17 and 3.71 +/- 0.53, respectively.
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29
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de Roos A, van der Wall EE. EVALUATION OF ISCHEMIC HEART DISEASE BY MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY. Radiol Clin North Am 1994. [DOI: 10.1016/s0033-8389(22)00390-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Yabe T, Mitsunami K, Okada M, Morikawa S, Inubushi T, Kinoshita M. Detection of myocardial ischemia by 31P magnetic resonance spectroscopy during handgrip exercise. Circulation 1994; 89:1709-16. [PMID: 8149536 DOI: 10.1161/01.cir.89.4.1709] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND The metabolic changes of myocardial ischemia in patients with coronary artery disease assessed by 31P magnetic resonance spectroscopy (MRS) have been reported previously. A significant decrease in the ratio of phosphocreatine (PCr) to ATP during handgrip exercise in a group of patients with severe coronary artery disease has been demonstrated. However, there are no reports at present that directly compare cardiac 31P MRS data with exercise 201Tl myocardial scintigraphy, now established as one of the most important clinical methods to assess myocardial ischemia. The purpose of this study was to investigate whether 31P MRS with handgrip exercise testing is able to detect myocardial ischemia, demonstrated by exercise 201Tl scintigraphy. METHODS AND RESULTS Twenty-seven patients with severe stenosis of the left anterior descending coronary artery (> or = 75%) and 11 normal control subjects composed the present study. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+]) who demonstrated redistribution at the late image and a fixed 201Tl defect group (RD[-]). While lying supine within the magnet, subjects performed handgrip exercise at 30% of maximal force once in every two cardiac cycles. 31P MR spectra were collected before and during handgrip exercise. Data were corrected for the saturation factor. ANOVA revealed significant differences among the three groups with respect to the mean +/- SD PCr/ATP ratio at rest (control, 1.85 +/- 0.28 > RD(+), 1.60 +/- 0.19 > RD(-), 1.24 +/- 0.30; P < .05). The PCr/ATP ratio decreased significantly from 1.60 +/- 0.19 at rest to 0.96 +/- 0.28 during exercise (P < .001) in the RD(+) group (n = 15). However, in the RD(-) group (n = 12), the ratio did not change significantly during handgrip exercise (1.24 +/- 0.30 at rest versus 1.19 +/- 0.28 during exercise). Similarly, the ratio did not change in the control group (n = 11) (1.85 +/- 0.28 at rest versus 1.90 +/- 0.23 during exercise). CONCLUSIONS Contrary to normal subjects or patients with fixed thallium defects, the PCr/ATP ratio was significantly altered by exercise in patients with reversible thallium defects. These results suggest that 31P MRS with handgrip exercise testing is a sensitive method for detecting myocardial ischemia.
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Affiliation(s)
- T Yabe
- First Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan
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31
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McDonald KM, Yoshiyama M, Francis GS, Ugurbil K, Cohn JN, Zhang J. Myocardial bioenergetic abnormalities in a canine model of left ventricular dysfunction. J Am Coll Cardiol 1994; 23:786-93. [PMID: 8113565 DOI: 10.1016/0735-1097(94)90769-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The purpose of this study was to assess high energy phosphate compound metabolism in remodeled left ventricular myocardium. BACKGROUND The development of heart failure several years after myocardial infarction is often unexplained. Certain abnormalities of remodeled myocardium suggest that structural changes occurring in viable myocardium after discrete myocardial damage may contribute to the later appearance of heart failure. Whether these abnormalities alter metabolism in the surviving muscle and thereby possibly contribute to ventricular dysfunction is unknown. METHODS High energy phosphate compound metabolism was assessed using spatially localized phosphorus-31 nuclear magnetic resonance spectroscopy. Eleven dogs with documented left ventricular dysfunction, resulting from infarction produced by transmyocardial direct current shock, were compared with eight normal dogs. Analyses were performed at baseline and during coronary hyperperfusion induced by intravenous adenosine. Myocardial blood flow was measured with radioactive microspheres. RESULTS The creatine phosphate/adenosine triphosphate (CP/ATP) ratio was significantly reduced in the left ventricular dysfunction group in both the subepicardium ([mean +/- SE] 1.94 +/- 0.08 vs. 2.32 +/- 0.13, p = 0.019) and the subendocardium (1.71 +/- 0.07 vs. 2.05 +/- 0.07, p = 0.004). Intravenous adenosine produced significant coronary hyperemia in both groups but was less marked in dogs with left ventricular dysfunction. The improvement in myocardial perfusion was accompanied by a significant increase in the subendocardial CP/ATP ratio (from 1.71 +/- 0.07 to 1.92 +/- 0.08, p = 0.01) in dogs with left ventricular dysfunction. CONCLUSIONS An abnormal transmural distribution of high energy phosphate compounds is evident in remodeled myocardium. This abnormality may be related in part to mismatch of oxygen delivery and demand.
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Affiliation(s)
- K M McDonald
- Department of Medicine, University of Minnesota, Minneapolis
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Hartiala J, Sakuma H, Higgins CB. Magnetic resonance imaging and spectroscopy of the human heart. Scand J Clin Lab Invest 1993; 53:425-37. [PMID: 8210964 DOI: 10.1080/00365519309092537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Magnetic resonance imaging and spectroscopy have a great potential both for clinical cardiac diagnostics and for research in cardiac physiology, metabolism and disease. At the present time, cardiac MRI already is the method of choice in several clinical conditions, especially in imaging central vasculature and intra- and paracardiac masses. With the recent development of contrast agents and ability to measure both flow velocities and flow volume, the cardiac MRI is likely to have a profound role in evaluating coronary arterial disease as well as valvular heart disease. The limitations due to long imaging times of cardiac MRI-studies are likely to be overcome with the development of ultrafast imaging techniques in the near future. On the other hand, cardiac MRS is still a research tool, which needs technical improvements before it can be widely utilized in clinical work. However, attempts to this aim are highly justified, when the possibility that MRS will provide metabolic information of the heart is considered and bearing in mind, that MR-magnets with sufficient field strength for MRS are increasingly in use in most modern hospitals. The role of magnetic resonance imaging (MRI) and spectroscopy (MRS) in the evaluation of heart diseases is still evolving. Some clear indications for clinical use of cardiac MRI have already become apparent, whereas cardiac MRS is still confined to research applications. The current paper consists of a review of the role of MRI for cardiovascular diagnosis together with a review of the currents status of cardiac MRS.
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Affiliation(s)
- J Hartiala
- Department of Radiology, University of California, San Francisco
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Sakuma H, Takeda K, Tagami T, Nakagawa T, Okamoto S, Konishi T, Nakano T. 31P MR spectroscopy in hypertrophic cardiomyopathy: comparison with Tl-201 myocardial perfusion imaging. Am Heart J 1993; 125:1323-8. [PMID: 8480584 DOI: 10.1016/0002-8703(93)91002-v] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Abnormal phosphate metabolism of the myocardium was evaluated in patients with hypertrophic cardiomyopathy (HCM) using 31P magnetic resonance (MR) spectroscopy. The results were compared with those from left ventricular function and thallium 201 (Tl-201) perfusion scintigraphy. Six normal volunteers and 19 patients with HCM were studied with a 1.5 T MR system. The spectra were localized to the myocardium using volume selection with the depth-resolved surface coil spectroscopy (DRESS) technique. Peak areas of 2,3-diphosphoglycerate (DPG), phosphodiesters (PDE), phosphocreatine (PCr), and beta-ATP were determined by fitting Gaussian functions to the phased spectra. The peak areas were corrected for contamination of blood adenosine triphosphate (ATP) and PDE. The corrected PCr/beta-ATP ratio in patients (1.07 +/- 0.10, mean +/- SE) was significantly lower compared with that in normal volunteers (1.71 +/- 0.13, p < .01). The PCr/beta-ATP ratio showed an abnormal decrease (< mean -2 SD of the controls) in 11 (58%) of 19 patients. The averaged PCr/beta-ATP ratio in 15 patients with normal left ventricular ejection fraction (LVEF) was 1.14 +/- 0.10, significantly lower than in healthy subjects. By contrast, the corrected PDE/PCr ratio in HCM did not differ significantly compared with that in healthy subjects (0.46 +/- 0.09 vs 0.36 +/- 0.09). The PDE/PCr ratio was abnormally elevated (> mean + 2 SD of the controls) in only four (21%) of the patients. On Tl-201 myocardial single-photon emission computed tomography (SPECT) imaging, the perfusion of the left ventricular wall looked normal in 6 and abnormal in 5 of 11 HCM patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- H Sakuma
- Department of Radiology, Mie University School of Medicine, Japan
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Neubauer S, Krahe T, Schindler R, Horn M, Hillenbrand H, Entzeroth C, Mader H, Kromer EP, Riegger GA, Lackner K. 31P magnetic resonance spectroscopy in dilated cardiomyopathy and coronary artery disease. Altered cardiac high-energy phosphate metabolism in heart failure. Circulation 1992; 86:1810-8. [PMID: 1451253 DOI: 10.1161/01.cir.86.6.1810] [Citation(s) in RCA: 271] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy. METHODS AND RESULTS Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly. CONCLUSIONS Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.
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Affiliation(s)
- S Neubauer
- Department of Medicine, Würzburg University, FRG
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36
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de Roos A, Doornbos J, Luyten PR, Oosterwaal LJ, van der Wall EE, den Hollander JA. Cardiac metabolism in patients with dilated and hypertrophic cardiomyopathy: assessment with proton-decoupled P-31 MR spectroscopy. J Magn Reson Imaging 1992; 2:711-9. [PMID: 1446116 DOI: 10.1002/jmri.1880020616] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Proton-decoupled phosphorus-31 heart spectroscopy was performed in healthy subjects (n = 9) and patients with dilated cardiomyopathy (DCM, n = 9) or hypertrophic cardiomyopathy (HCM, n = 8). The phosphocreatine (PCr)-to-adenosine triphosphate ratio (+/- one standard deviation) after correction for blood contribution and partial saturation was significantly lower in HCM patients relative to the control subjects (1.32 +/- 0.29 vs 1.65 +/- 0.26, P < .05) but not in DCM patients (1.52 +/- 0.58 vs 1.65 +/- 0.26). The inorganic phosphate (Pi) peak was resolved only in patients with the highest spectral quality. Myocardial pH was lower in HCM patients (n = 6) relative to control subjects (n = 4) (7.07 +/- 0.07 vs 7.15 +/- 0.03, P < .05). The Pi/PCr ratio was higher in DCM (n = 3) and HCM (n = 6) patients relative to control subjects (n = 4) (0.29 +/- 0.06 and 0.20 +/- 0.04, respectively, vs 0.14 +/- 0.06; P < .05). Elevated phosphodiester signal in DCM patients correlated with 2,3-diphosphoglycerate signal (r = .94), reflecting blood pool contamination. P-31 spectroscopy enabled detection of abnormalities in cardiac metabolism and determination of pH in patients with HCM and DCM.
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Affiliation(s)
- A de Roos
- Department of Diagnostic Radiology, University Hospital Leiden, The Netherlands
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Hardy CJ, Bottomley PA, Rohling KW, Roemer PB. An NMR phased array for human cardiac 31P spectroscopy. Magn Reson Med 1992; 28:54-64. [PMID: 1435221 DOI: 10.1002/mrm.1910280106] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A four-coil phased-array 31P NMR receiver was designed and tested for human cardiac applications, to determine whether the combination of relatively high signal-to-noise ratio (SNR) and large field of view produced in 1H imaging is also realized for in vivo 31P spectroscopy. Spectra were acquired in parallel from an array of four overlapping 6.5-cm surface coils using one- and two-dimensional phase-encoding pulse sequences and were optimally combined to yield composite spectroscopic images. The phased array was found to generate useful 31P spectra from a 2.5-fold wider lateral region around the anterior myocardium than a single receiver of the same size as the array elements, with no increase in imaging time. In addition, the sensitive depth was increased by up to 2 cm over that of a single coil. Spectra could be acquired in roughly 15 min from a region extending to the middle of the heart, with voxel sizes of 2 x 2 x 4 cm3. For the average heart voxel, the SNR of the combined spectrum was higher than that of the best spectrum from any one coil in the array by 30%, with some voxels showing an increase as high as 60%.
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Affiliation(s)
- C J Hardy
- GE Corporate Research and Development Center, Schenectady, New York 12301
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38
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Neubauer S, Krahe T, Schindler R, Hillenbrand H, Entzeroth C, Horn M, Bauer WR, Stephan T, Lackner K, Haase A. Direct measurement of spin-lattice relaxation times of phosphorus metabolites in human myocardium. Magn Reson Med 1992; 26:300-7. [PMID: 1513251 DOI: 10.1002/mrm.1910260209] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
T1 values of phosphorus metabolites visible in human cardiac 31P-MR spectra were determined in 12 volunteers at 1.5 T. Consecutive spectra were acquired with varying pulse repetition time (TR) from 1.6 to 24 s; volume selection was achieved with ISIS. T1's of creatine phosphate (CP), [gamma-P], [alpha-P], and [beta-P]ATP, 2-3 diphosphoglycerate, and phosphodiesters were 6.1 +/- 0.5, 5.4 +/- 0.5, 5.5 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s, respectively. CP/ATP ratios showed little change with varying TR; linear regression of CP/ATP vs TR was of borderline significance (r = 0.28, P = 0.06). T1's for CP and ATP were also determined in standard solution (20 mM CP, 10 mM ATP) yielding T1CP of 8.7 +/- 0.2 and T1[gamma-P]-ATP of 9.9 +/- 0.7 s. Thus, T1's for CP and ATP were similar at 1.5 T in both human heart and standard solution. In human cardiac 31P-MR spectra, CP/ATP ratios may need little correction for partial saturation.
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Affiliation(s)
- S Neubauer
- Department of Medicine, University of Würzburg, Germany
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39
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Schaefer S, Schwartz GG, Steinman SK, Meyerhoff DJ, Massie BM, Weiner MW. Metabolic response of the human heart to inotropic stimulation: in vivo phosphorus-31 studies of normal and cardiomyopathic myocardium. Magn Reson Med 1992; 25:260-72. [PMID: 1614310 DOI: 10.1002/mrm.1910250205] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In order to determine if an increase in myocardial oxygen consumption is accompanied by changes in high energy phosphates in normal subjects and patients with dilated cardiomyopathy, phosphorus-31 spectra were acquired under resting conditions and during dobutamine infusion. In seven normal subjects, dobutamine raised the rate-pressure product to 226% of control. The ratio of PCr/ATP was 1.86 +/- 0.17 (mean +/- SE) under resting conditions and 1.90 +/- 0.22 (P = 0.44) with dobutamine infusion. In eight patients with dilated cardiomyopathy, dobutamine raised the rate-pressure product to 161% of control. As in the normal subjects, the ratio of PCr/ATP under resting conditions (1.63 +/- 0.24) was unchanged during dobutamine infusion (1.57 +/- 0.24, P = 0.38). These data indicate that increases in cardiac work do not have a major effect on high energy phosphate concentrations in normal subjects or in patients with clinically compensated dilated cardiomyopathy.
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Affiliation(s)
- S Schaefer
- Magnetic Resonance Unit VA Medical Center, San Francisco, California
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40
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Abstract
Writing a critique and guide for authors of clinical spectroscopy research papers is a likely way of ensuring that one never sees another of one's own papers published in this field. Nevertheless, it is disappointing, though perhaps predictable, that despite its historical foundations in quantitative spectroscopy, the field has its fair share of findings that are not so obviously reconciled. Here is the view of one author, one referee, and one spectroscopy protagonist about what might be expected of a clinical spectroscopy paper. In addition to novelty, the fundamental criteria for acceptance should be that the conclusions are supported by properly and objectively quantified results, and that sufficient experimental detail is provided so that one skilled in the art could reproduce the study and its findings.
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Meyerhoff DJ, Maudsley AA, Schaefer S, Weiner MW. Phosphorus-31 magnetic resonance metabolite imaging in the human body. Magn Reson Imaging 1992; 10:245-56. [PMID: 1564993 DOI: 10.1016/0730-725x(92)90484-h] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This work examines the feasibility of three-dimensional phosphorus-31 magnetic resonance spectroscopic imaging (31P MRSI) of metabolites in the human body using nonselective excitation with a single large circular surface coil for transmitting and receiving. The potential and limitations of this approach to clinical imaging are demonstrated on four selected examples: normal liver and heart, hematoma in the calf, and lymphoma in the groin. The obtained metabolite images showed anatomical detail and allowed differentiation of body organs and pathologic tissue from adjacent tissue. Three-dimensionally localized 31P spectra were reconstructed from nominal volumes of 4 to 15 cm3. These spectra showed characteristic resonances and metabolite intensity ratios for the tissue of origin demonstrating good three-dimensional localization. We conclude that surface coil 31P MRSI of body organs to map metabolite distributions is practically feasible with this approach, but due to experimental limitations, clinical utility requires technical improvements.
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Affiliation(s)
- D J Meyerhoff
- Magnetic Resonance Unit, DVA Medical Center, San Francisco, CA 94121
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42
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Syrota A, Jehenson P. Complementarity of magnetic resonance spectroscopy, positron emission tomography and single photon emission tomography for the in vivo investigation of human cardiac metabolism and neurotransmission. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1991; 18:897-923. [PMID: 1661237 DOI: 10.1007/bf02258457] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The three techniques allowing the noninvasive study of cardiac metabolism, namely magnetic resonance spectroscopy (MRS), positron emission tomography (PET) and single photon emission computed tomography (SPET), all use external detection with stable or radioactive isotopes. These techniques yield different information. PET is quantitative and very sensitive, and therefore only tracer amounts of molecules need to be injected. It allows neurotransmitters and receptors to be studied and a global view of metabolism (oxygen consumption, glucose and fatty acid utilization) to be obtained. SPET also has good sensitivity, but uses gamma-emitting isotopes of heteroatoms. Their longer half-lives allow follow-up for hours or days. MRS is based on stable elements with high (hydrogen 1, phosphorus 31, fluorine 19...) or low (carbon 13, Deuterium) natural abundance. It has very low sensitivity and only millimolar concentrations of substrates can be detected, but various parts of metabolism can be studied. The in vivo measurement of myocardial concentration of substances has many problems that are common to all three techniques (measurement of the volume, measurement of the quantity of each molecule, resolution, partial volume effect, improvement of the signal-to-noise ratio, movement of the organ). The complementarity of the techniques is illustrated by their applications to the study of cardiac metabolism. For instance, the energy metabolism can be studied by 31P-MRS, which detects the high-energy compounds ATP and phosphocreatine, and 13C-MRS yields information on the tricarboxylic acid cycle activity. PET and SPET allow the utilization of fatty acids, the normal fuels of the heart, to be studied. During ischaemia, PET with 18F-fluorodeoxyglucose (18FDG) can determine the glucose consumption and 1H-MRS shows the increase in lactic acid, reflecting anaerobic glycolysis. Comparison of the use of acetate labelled with 11C for PET or 13C for MRS shows the potentials and limitations of each technique. Myocardial perfusion can be evaluated directly with various PET tracers or indirectly with thallium 201 or various technetium-99m-labelled tracers by SPET. No MRS marker of perfusion is so far clinically available. Mainly SPET and PET are used clinically for the investigation of ischaemic heart disease as well as cardiomyopathies, but some initial results using 31P-MRS are being obtained.
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Affiliation(s)
- A Syrota
- Service Hospitalier Frédéric Joliot, Orsay, France
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Scholz TD, Grover-McKay M, Fleagle SR, Skorton DJ. Quantitation of the extent of acute myocardial infarction by phosphorus-31 nuclear magnetic resonance spectroscopy. J Am Coll Cardiol 1991; 18:1380-7. [PMID: 1918716 DOI: 10.1016/0735-1097(91)90562-n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy is able to identify alterations in myocardial high energy phosphate metabolism associated with acute infarction. It was hypothesized that the extent of acute myocardial infarction could be quantitated from changes in the tissue content of inorganic phosphate (Pi), phosphocreatine (PCr) and adenosine triphosphate (ATP) derived from P-31 NMR spectra. Nine isolated, perfused rat hearts were studied at 121.5 MHz. After baseline spectra were obtained, varying locations of either the right or the left coronary artery were occluded without removing the heart from the spectrometer. Spectra were then collected during regional ischemia at 15 and 45 min after occlusion. Phosphate metabolites were quantitated from the baseline and 45-min regional ischemia spectra, times at which the metabolites are at steady state for the normal and ischemic conditions. The heart was removed from the spectrometer, perfused for a total duration of 2 h and sectioned into 2-mm thick slices for triphenyltetrazolium chloride staining. Percent infarct was determined by manual tracing of magnified, digitized images of the stained sections. Coronary blood flow, heart rate and blood pressure were monitored throughout the experiment. Significant linear relations were found between percent infarct (by triphenyltetrazolium chloride staining) and the percent change of beta-ATP (r = -0.74), Pi (r = 0.83) and the PCr/Pi ratio (r = -0.71) at 45 min after coronary occlusion. Coronary flow was also found to correlate significantly with percent infarct (r = -0.70). These results are applicable to in vivo P-31 NMR studies of acute infarction where the volume of interest may include both normal and acutely infarcted myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T D Scholz
- Cardiovascular Center, University of Iowa, Iowa City 52242
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Hardy CJ, Weiss RG, Bottomley PA, Gerstenblith G. Altered myocardial high-energy phosphate metabolites in patients with dilated cardiomyopathy. Am Heart J 1991; 122:795-801. [PMID: 1877457 DOI: 10.1016/0002-8703(91)90527-o] [Citation(s) in RCA: 151] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Myocardial high-energy phosphate metabolism in patients with dilated cardiomyopathy (DCM) of ischemic or idiopathic etiology was assessed at rest by one-dimensional phase-encoded 31P-nuclear magnetic resonance (NMR) spectroscopy studies performed in conjunction with 1H imaging in 20 patients with DCM and in 12 normal volunteers. The measured values of anterior myocardial phosphocreatine/beta-adenosine triphosphate (PCr/beta-ATP), corrected for partial saturation and contamination of the spectra by blood metabolites, averaged 1.80 +/- 0.06 (mean +/- SE) in normal volunteers and 1.46 +/- 0.07 in the patients overall, a highly significant (p less than 0.001) decrease. In patients with DCM accompanied by coronary artery disease (n = 9), the PCr/beta-ATP ratio averaged 1.53 +/- 0.07, while in those with DCM alone it was 1.41 +/- 0.12 (n = 11), a value that was not significantly different. There was no significant correlation (r = 0.34) between myocardial PCr/ATP ratio and left ventricular ejection fraction in patients. These studies demonstrate that myocardial PCr/ATP ratios are reduced at rest in human ischemic and idiopathic dilated cardiomyopathy.
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Affiliation(s)
- C J Hardy
- GE Corporate Research and Development Center, Schenectady, NY 12301
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45
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Abstract
Nuclear magnetic resonance (NMR) spectroscopy can nondestructively evaluate changes in metabolites with different disease states, as well as with therapeutic interventions. Animal studies have provided the basis for understanding changes in high-energy phosphates with myocardial ischemia. Studies of graded ischemia due to partial coronary stenosis have shown the sensitivity of the ratio of phosphocreatinine to inorganic phosphate to small reductions in myocardial blood flow and its relation to myocardial function. The application of NMR spectroscopy to humans requires precise localization techniques to avoid acquiring contaminating information from structures around the heart, such as the chest wall and diaphragm. With these localization techniques, metabolic evidence of ischemia has been demonstrated in patients with myocardial infarction and patients with known coronary disease, although the sensitivity of this technique for the diagnosis of inducible ischemia is unknown. At rest, patients with dilated and hypertrophic cardiomyopathies often have an elevated phosphodiester resonance, possibly signifying abnormal breakdown of membrane phospholipids. Increasing oxygen demand in these patients does not usually alter high-energy phosphates, suggesting that oxidative energy metabolism is preserved under these conditions. NMR spectroscopy is a powerful tool to increase understanding of metabolic changes in a variety of pathologic conditions.
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Affiliation(s)
- S Schaefer
- Veterans Administration Medical Center, San Francisco, California 94143
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