1
|
Elsaid NMH, Peters DC, Galiana G, Sinusas AJ. Clinical physiology: the crucial role of MRI in evaluation of peripheral artery disease. Am J Physiol Heart Circ Physiol 2024; 326:H1304-H1323. [PMID: 38517227 PMCID: PMC11381027 DOI: 10.1152/ajpheart.00533.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 03/23/2024]
Abstract
Peripheral artery disease (PAD) is a common vascular disease that primarily affects the lower limbs and is defined by the constriction or blockage of peripheral arteries and may involve microvascular dysfunction and tissue injury. Patients with diabetes have more prominent disease of microcirculation and develop peripheral neuropathy, autonomic dysfunction, and medial vascular calcification. Early and accurate diagnosis of PAD and disease characterization are essential for personalized management and therapy planning. Magnetic resonance imaging (MRI) provides excellent soft tissue contrast and multiplanar imaging capabilities and is useful as a noninvasive imaging tool in the comprehensive physiological assessment of PAD. This review provides an overview of the current state of the art of MRI in the evaluation and characterization of PAD, including an analysis of the many applicable MR imaging techniques, describing the advantages and disadvantages of each approach. We also present recent developments, future clinical applications, and future MRI directions in assessing PAD. The development of new MR imaging technologies and applications in preclinical models with translation to clinical research holds considerable potential for improving the understanding of the pathophysiology of PAD and clinical applications for improving diagnostic precision, risk stratification, and treatment outcomes in patients with PAD.
Collapse
Affiliation(s)
- Nahla M H Elsaid
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Dana C Peters
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
| | - Gigi Galiana
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
| | - Albert J Sinusas
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
- Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, United States
| |
Collapse
|
2
|
Raj V, Gowda S, Kothari R. Myocardial tissue characterization by cardiac magnetic resonance: A primer for the clinician. JOURNAL OF THE INDIAN ACADEMY OF ECHOCARDIOGRAPHY & CARDIOVASCULAR IMAGING 2023. [DOI: 10.4103/jiae.jiae_44_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
|
3
|
Dendy JM, Hughes SG, Soslow JH, Clark DE, Paschal CB, Gore JC. Myocardial Tissue Oxygenation and Microvascular Blood Volume Measurement Using a Contrast Blood Oxygenation Level-Dependent Imaging Model. Invest Radiol 2022; 57:561-566. [PMID: 35438656 PMCID: PMC9355912 DOI: 10.1097/rli.0000000000000871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES We propose a method of quantitatively measuring drug-induced microvascular volume changes, as well as drug-induced changes in blood oxygenation using calibrated blood oxygen level-dependent magnetic resonance imaging (MRI). We postulate that for MRI signals there is a contribution to R2* relaxation rates from static susceptibility effects of the intravascular blood that scales with the blood volume/magnetic field and depends on the oxygenation state of the blood. These may be compared with the effects of an intravascular contrast agent. With 4 R2* measurements, microvascular blood volume (MBV) and tissue oxygenation changes can be quantified with the administration of a vasoactive drug. MATERIALS AND METHODS The protocol examined 12 healthy rats in a prospective observational study. R2* maps were acquired with and without infusion of adenosine, which increases microvascular blood flow, or dobutamine, which increases myocardial oxygen consumption. In addition, R2* maps were acquired after the intravenous administration of a monocrystalline iron oxide nanoparticle, with and without adenosine or dobutamine. RESULTS Total microvascular volume was shown to increase by 10.8% with adenosine and by 25.6% with dobutamine ( P < 0.05). When comparing endocardium versus epicardium, both adenosine and dobutamine demonstrated significant differences between endocardial and epicardial MBV changes ( P < 0.05). Total myocardial oxygenation saturation increased by 6.59% with adenosine and by 1.64% with dobutamine ( P = 0.27). The difference between epicardial and endocardial oxygenation changes were significant with each drug (adenosine P < 0.05, dobutamine P < 0.05). CONCLUSIONS Our results demonstrate the ability to quantify microvascular volume and oxygenation changes using calibrated blood oxygen level-dependent MRI, and we demonstrate different responses of adenosine and dobutamine. This method has clinical potential in examining microvascular disease in various disease states without the administration of radiopharmaceuticals or gadolinium-based contrast agents.
Collapse
Affiliation(s)
- Jeffrey M Dendy
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Vanderbilt University Medical Center
| | - Sean G Hughes
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Vanderbilt University Medical Center
| | - Jonathan H Soslow
- Thomas P. Graham Division of Pediatric Cardiology, Department of Pediatrics, Monroe Carell Jr. Children's Hospital at Vanderbilt
| | - Daniel E Clark
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Vanderbilt University Medical Center
| | | | | |
Collapse
|
4
|
Dube R. Does endothelial dysfunction correlate with endocrinal abnormalities in patients with polycystic ovary syndrome? Avicenna J Med 2021; 6:91-102. [PMID: 27843797 PMCID: PMC5054651 DOI: 10.4103/2231-0770.191445] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To study and critically analyze the published evidence on correlation of hormonal abnormalities and endothelial dysfunction (ED) in polycystic ovary syndrome (PCOS) through a systematic review. The databases including MEDLINE, PubMed, Up-To-Date, and Science Direct were searched using Medical subject handling terms and free text term keywords such as endocrine abnormalities in PCOS, ED assessment in PCOS, ED in combination with insulin resistance (IR), hyperandrogenism (HA), increased free testosterone, free androgen index (FAI), gonadotrophin levels, luteinizing hormone (LH), prolactin, estrogen, adipocytokines to search trials, and observational studies published from January 1987 to September 2015. Authors of original studies were contacted for additional data when necessary. PCOS increases the risk of cardiovascular disease in women. ED, which is a reliable indicator of cardiovascular risk in general population, is seen in most (but not all) women with PCOS. IR, seen in 70% patients with PCOS, is associated with ED in these women, but patients can have normal endothelial function even in the presence of IR. Free testosterone and FAI are consistently associated with ED, but endothelial function can be normal despite HA. Estradiol (not estrone) appears to be protective against ED though estrone is the predominant estrogen produced in PCOS. Increased levels of adipocytokines (visfatin) are promising in predicting ED and cardiovascular risk. However, more studies are required focusing on direct correlation of levels of prolactin, LH, estrone, and visfatin with ED in PCOS.
Collapse
Affiliation(s)
- Rajani Dube
- Department of Obstetrics and Gynaecology, Ras al-Khaimah Medical and Health Sciences University, Al Qusaidat, Ras al-Khaimah, United Arab Emirates
| |
Collapse
|
5
|
Troy AM, Cheng HM. Human microvascular reactivity: a review of vasomodulating stimuli and non-invasive imaging assessment. Physiol Meas 2021; 42. [PMID: 34325417 DOI: 10.1088/1361-6579/ac18fd] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/29/2021] [Indexed: 11/11/2022]
Abstract
The microvasculature serves an imperative function in regulating perfusion and nutrient exchange throughout the body, adaptively altering blood flow to preserve hemodynamic and metabolic homeostasis. Its normal functioning is vital to tissue health, whereas its dysfunction is present in many chronic conditions, including diabetes, heart disease, and cognitive decline. As microvascular dysfunction often appears early in disease progression, its detection can offer early diagnostic information. To detect microvascular dysfunction, one uses imaging to probe the microvasculature's ability to react to a stimulus, also known as microvascular reactivity (MVR). An assessment of MVR requires an integrated understanding of vascular physiology, techniques for stimulating reactivity, and available imaging methods to capture the dynamic response. Practical considerations, including compatibility between the selected stimulus and imaging approach, likewise require attention. In this review, we provide a comprehensive foundation necessary for informed imaging of MVR, with a particular focus on the challenging endeavor of assessing microvascular function in deep tissues.
Collapse
Affiliation(s)
- Aaron M Troy
- Institute of Biomedical Engineering, University of Toronto, Toronto, CANADA
| | | |
Collapse
|
6
|
Lopez C, Taivassalo T, Berru MG, Saavedra A, Rasmussen HC, Batra A, Arora H, Roetzheim AM, Walter GA, Vandenborne K, Forbes SC. Postcontractile blood oxygenation level-dependent (BOLD) response in Duchenne muscular dystrophy. J Appl Physiol (1985) 2021; 131:83-94. [PMID: 34013753 PMCID: PMC8325615 DOI: 10.1152/japplphysiol.00634.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 04/28/2021] [Accepted: 05/13/2021] [Indexed: 11/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is characterized by a progressive replacement of muscle by fat and fibrous tissue, muscle weakness, and loss of functional abilities. Impaired vasodilatory and blood flow responses to muscle activation have also been observed in DMD and associated with mislocalization of neuronal nitric oxide synthase mu (nNOSμ) from the sarcolemma. The objective of this study was to determine whether the postcontractile blood oxygen level-dependent (BOLD) MRI response is impaired in DMD and correlated with established markers of disease severity in DMD, including MRI muscle fat fraction (FF) and clinical functional measures. Young boys with DMD (n = 16, 5-14 yr) and unaffected controls (n = 16, 5-14 yr) were evaluated using postcontractile BOLD, FF, and functional assessments. The BOLD response was measured following five brief (2 s) maximal voluntary dorsiflexion contractions, each separated by 1 min of rest. FFs from the anterior compartment lower leg muscles were quantified via chemical shift-encoded imaging. Functional abilities were assessed using the 10 m walk/run and the 6-min walk distance (6MWD). The peak BOLD responses in the tibialis anterior and extensor digitorum longus were reduced (P < 0.001) in DMD compared with controls. Furthermore, the anterior compartment peak BOLD response correlated with function (6MWD ρ = 0.87, P < 0.0001; 10 m walk/run time ρ = -0.78, P < 0.001) and FF (ρ = -0.52, P = 0.05). The reduced postcontractile BOLD response in DMD may reflect impaired microvascular function. The relationship observed between the postcontractile peak BOLD response and functional measures and FF suggests that the BOLD response is altered with disease severity in DMD.NEW & NOTEWORTHY This study examined the postcontractile blood oxygen level-dependent (BOLD) response in boys with Duchenne muscular dystrophy (DMD) and unaffected controls, and correlated this measure to markers of disease severity. Our findings indicate that the postcontractile BOLD response is impaired in DMD after brief muscle contractions, is correlated to disease severity, and may be valuable to implement in future studies to evaluate treatments targeting microvascular function in DMD.
Collapse
Affiliation(s)
- Christopher Lopez
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Tanja Taivassalo
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Maria G Berru
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Andres Saavedra
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Hannah C Rasmussen
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Abhinandan Batra
- Department of Physical Therapy, University of Florida, Gainesville, Florida
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Harneet Arora
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Alex M Roetzheim
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Krista Vandenborne
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Sean C Forbes
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| |
Collapse
|
7
|
Guerraty M, Bhargava A, Senarathna J, Mendelson AA, Pathak AP. Advances in translational imaging of the microcirculation. Microcirculation 2021; 28:e12683. [PMID: 33524206 PMCID: PMC8647298 DOI: 10.1111/micc.12683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 12/21/2022]
Abstract
The past few decades have seen an explosion in the development and use of methods for imaging the human microcirculation during health and disease. The confluence of innovative imaging technologies, affordable computing power, and economies of scale have ushered in a new era of "translational" imaging that permit us to peer into blood vessels of various organs in the human body. These imaging techniques include near-infrared spectroscopy (NIRS), positron emission tomography (PET), and magnetic resonance imaging (MRI) that are sensitive to microvascular-derived signals, as well as computed tomography (CT), optical imaging, and ultrasound (US) imaging that are capable of directly acquiring images at, or close to microvascular spatial resolution. Collectively, these imaging modalities enable us to characterize the morphological and functional changes in a tissue's microcirculation that are known to accompany the initiation and progression of numerous pathologies. Although there have been significant advances for imaging the microcirculation in preclinical models, this review focuses on developments in the assessment of the microcirculation in patients with optical imaging, NIRS, PET, US, MRI, and CT, to name a few. The goal of this review is to serve as a springboard for exploring the burgeoning role of translational imaging technologies for interrogating the structural and functional status of the microcirculation in humans, and highlight the breadth of current clinical applications. Making the human microcirculation "visible" in vivo to clinicians and researchers alike will facilitate bench-to-bedside discoveries and enhance the diagnosis and management of disease.
Collapse
Affiliation(s)
- Marie Guerraty
- Division of Cardiovascular Medicine, Department of
Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,
USA
| | - Akanksha Bhargava
- Russell H. Morgan Department of Radiology and Radiological
Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Janaka Senarathna
- Russell H. Morgan Department of Radiology and Radiological
Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Asher A. Mendelson
- Department of Medicine, Section of Critical Care, Rady
Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Arvind P. Pathak
- Russell H. Morgan Department of Radiology and Radiological
Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, The Johns Hopkins
University School of Medicine, Baltimore, MD, USA
- Department of Electrical Engineering, Johns Hopkins
University, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns
Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
8
|
Alexander Y, Osto E, Schmidt-Trucksäss A, Shechter M, Trifunovic D, Duncker DJ, Aboyans V, Bäck M, Badimon L, Cosentino F, De Carlo M, Dorobantu M, Harrison DG, Guzik TJ, Hoefer I, Morris PD, Norata GD, Suades R, Taddei S, Vilahur G, Waltenberger J, Weber C, Wilkinson F, Bochaton-Piallat ML, Evans PC. Endothelial function in cardiovascular medicine: a consensus paper of the European Society of Cardiology Working Groups on Atherosclerosis and Vascular Biology, Aorta and Peripheral Vascular Diseases, Coronary Pathophysiology and Microcirculation, and Thrombosis. Cardiovasc Res 2021; 117:29-42. [PMID: 32282914 PMCID: PMC7797212 DOI: 10.1093/cvr/cvaa085] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/08/2020] [Accepted: 04/07/2020] [Indexed: 12/14/2022] Open
Abstract
Endothelial cells (ECs) are sentinels of cardiovascular health. Their function is reduced by the presence of cardiovascular risk factors, and is regained once pathological stimuli are removed. In this European Society for Cardiology Position Paper, we describe endothelial dysfunction as a spectrum of phenotypic states and advocate further studies to determine the role of EC subtypes in cardiovascular disease. We conclude that there is no single ideal method for measurement of endothelial function. Techniques to measure coronary epicardial and micro-vascular function are well established but they are invasive, time-consuming, and expensive. Flow-mediated dilatation (FMD) of the brachial arteries provides a non-invasive alternative but is technically challenging and requires extensive training and standardization. We, therefore, propose that a consensus methodology for FMD is universally adopted to minimize technical variation between studies, and that reference FMD values are established for different populations of healthy individuals and patient groups. Newer techniques to measure endothelial function that are relatively easy to perform, such as finger plethysmography and the retinal flicker test, have the potential for increased clinical use provided a consensus is achieved on the measurement protocol used. We recommend further clinical studies to establish reference values for these techniques and to assess their ability to improve cardiovascular risk stratification. We advocate future studies to determine whether integration of endothelial function measurements with patient-specific epigenetic data and other biomarkers can enhance the stratification of patients for differential diagnosis, disease progression, and responses to therapy.
Collapse
Affiliation(s)
- Yvonne Alexander
- Centre for Bioscience, Faculty of Science & Engineering, Manchester Metropolitan University, Manchester, UK
| | - Elena Osto
- Institute of Clinical Chemistry, University and University Hospital Zurich, University Heart Center, Zurich, Switzerland
- Laboratory of Translational Nutrition Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Arno Schmidt-Trucksäss
- Division of Sports and Exercise Medicine, Department of Sport, Exercise and Health, Medical Faculty, University of Basel, Basel, Switzerland
| | - Michael Shechter
- Leviev Heart Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Danijela Trifunovic
- Cardiology Department, Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Dirk J Duncker
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Victor Aboyans
- Department of Cardiology, Dupuytren University Hospital, Inserm U-1094, Limoges University, Limoges, France
| | - Magnus Bäck
- Department of Cardiology, Center for Molecular Medicine, Karolinska University Hospital, Solna, Stockholm, Sweden
- INSERM U1116, Université de Lorraine, Centre Hospitalier Régional Universitaire de Nancy, Vandoeuvre les Nancy, France
| | - Lina Badimon
- Cardiovascular Program-ICCC, IR-Hospital de la Santa Creu i Sant Pau, CiberCV, Autonomous University of Barcelona, Barcelona, Spain
| | - Francesco Cosentino
- Unit of Cardiology, Karolinska Institute and Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Marco De Carlo
- Catheterization Laboratory, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Maria Dorobantu
- ‘CarolDavila’ University of Medicine and Pharmacy, Bucharest, Romania
| | | | - Tomasz J Guzik
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
- Department of Medicine, Jagiellonian University Collegium Medicum, Cracow, Poland
| | - Imo Hoefer
- Laboratory of Clinical Chemistry and Hematology, University Medical Centre Utrecht, The Netherlands
| | - Paul D Morris
- Department of Infection, Immunity and Cardiovascular Disease, Bateson Centre & INSIGNEO Institute, University of Sheffield, Sheffield S10 2RX, UK
- Insigneo Institute for In Silico Medicine, Sheffield, UK
| | - Giuseppe D Norata
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - Rosa Suades
- Unit of Cardiology, Karolinska Institute and Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Stefano Taddei
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gemma Vilahur
- Cardiovascular Program-ICCC, IR-Hospital de la Santa Creu i Sant Pau, CiberCV, Autonomous University of Barcelona, Barcelona, Spain
| | - Johannes Waltenberger
- Department of Cardiovascular Medicine, Medical Faculty, University of Münster, Münster, Germany
- SRH Central Hospital Suhl, Suhl, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximillian-Universität (LMU) München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Fiona Wilkinson
- Centre for Bioscience, Faculty of Science & Engineering, Manchester Metropolitan University, Manchester, UK
| | | | - Paul C Evans
- Department of Infection, Immunity and Cardiovascular Disease, Bateson Centre & INSIGNEO Institute, University of Sheffield, Sheffield S10 2RX, UK
- Insigneo Institute for In Silico Medicine, Sheffield, UK
| |
Collapse
|
9
|
Luu JM, Schmidt A, Flewitt J, Mikami Y, Ter Keurs H, Friedrich MG. Cardiovascular risk is associated with a transmural gradient of myocardial oxygenation during adenosine infusion. Eur Heart J Cardiovasc Imaging 2020; 20:1287-1295. [PMID: 30590548 DOI: 10.1093/ehjci/jey202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/17/2018] [Indexed: 11/12/2022] Open
Abstract
AIMS In patients with coronary artery disease (CAD), a transmural gradient of myocardial perfusion has been repeatedly observed, with the subendocardial layer showing more pronounced perfusion deficits. Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) allows for monitoring transmural changes of myocardial oxygenation in vivo. We hypothesized that OS-CMR could help identify a transmural oxygenation gradient as a disease marker in patients at risk for CAD. METHODS AND RESULTS We assessed 34 patients with known CAD and 28 subjects with coronary risk factors but no evidence of significant CAD. Results were compared with 11 healthy volunteers. OS-CMR was performed at 1.5 T, applying a T2*-weighted cine steady state free precession sequence at baseline and during infusion of adenosine. A reader blinded to patient data quantified the relative change of myocardial oxygenation in OS-CMR, defined by the change of signal intensity (ΔSI%) between baseline and during adenosine infusion in the entire myocardium, the subepicardial layer, and the subendocardial layer. SI changes were homogenous throughout the myocardium in healthy subjects, whereas both, patients with risk factors only and patients with CAD, had a significantly smaller ΔSI% in the subendocardial layer than in the subendocardial layer. Both patient groups had an overall decreased ΔSI% across all layers when compared with healthy subjects (P < 0.05). CONCLUSION Even in the absence of overt CAD, cardiovascular risk factors are associated with a transmural gradient of the myocardial oxygenation response to adenosine as assessed by OS-CMR. An inducible transmural oxygenation gradient may serve as a non-invasive marker for cardiovascular risk.
Collapse
Affiliation(s)
- Judy M Luu
- Division of Cardiology, Department of Medicine, University of Manitoba, 409 Tache Avenue, Winnipeg, Manitoba, Canada
| | - Anna Schmidt
- Department of Cardiac Sciences, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute of Alberta, Foothills Medical Centre, Suite 0700-SSB, 1403-29th Street NW, Calgary AB, Canada
| | - Jacqueline Flewitt
- Department of Cardiac Sciences, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute of Alberta, Foothills Medical Centre, Suite 0700-SSB, 1403-29th Street NW, Calgary AB, Canada
| | - Yoko Mikami
- Department of Cardiac Sciences, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute of Alberta, Foothills Medical Centre, Suite 0700-SSB, 1403-29th Street NW, Calgary AB, Canada
| | - Henk Ter Keurs
- Department of Cardiac Sciences, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute of Alberta, Foothills Medical Centre, Suite 0700-SSB, 1403-29th Street NW, Calgary AB, Canada
| | - Matthias G Friedrich
- Departments of Cardiology and Diagnostic Radiology, McGill University Health Centre, Royal Victoria Hospital, 1001 Decarie Blvd, Montreal, Canada.,Department of Radiology, Université de Montréal, Pavillon Roger-Gaudry - Local S-716, Montréal QC, Canada.,Departments of Cardiac Sciences and Radiology, University of Calgary, 3330 Hospital Dr. NW, Calgary AB, Canada
| |
Collapse
|
10
|
Hurley DM, Williams ER, Cross JM, Riedinger BR, Meyer RA, Abela GS, Slade JM. Aerobic Exercise Improves Microvascular Function in Older Adults. Med Sci Sports Exerc 2019; 51:773-781. [PMID: 30489496 DOI: 10.1249/mss.0000000000001854] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microvascular function is reduced with age, disease, and inactivity. Exercise is well known to improve vascular health and has the potential to improve microvascular function in aging and disease. PURPOSE The study aimed to assess changes in peripheral microvascular function in sedentary older adults after aerobic exercise training. METHODS Twenty-three sedentary older adults (67 ± 5 yr, body mass index = 29 ± 5, mean ± SD) successfully completed a randomized 12-wk graded treadmill walking intervention. The exercise group (EX) performed 40 min of uphill walking 4 d·wk at 70% heart rate reserve. The control group (CON) maintained a sedentary lifestyle for 12 wk. Blood oxygen level-dependent (BOLD) responses of the soleus measured by magnetic resonance imaging were used to evaluate microvascular function; brief (1 s) maximal plantarflexion contractions were performed. Separately, blood flow in the popliteal artery was measured by ultrasound after brief contraction. Phosphorus magnetic resonance spectroscopy of the calf was used to examine muscle oxidative capacity, and whole-body peak oxygen consumption (V˙O2peak) was used to confirm training-induced cardiorespiratory adaptations. RESULTS Peak postcontraction BOLD response increased by 33% in EX (PRE, 3.3% ± 1.0%; POST, 4.4% ± 1.4%) compared with CON (PRE, 3.0% ± 1.3%; POST, 3.2% ± 1.5%), P < 0.05. EX with hypertension tended to show a blunted peak BOLD increase (n = 6, 15%) compared with EX normotensive (n = 7, 50%), P = 0.056. Peak postcontraction blood flow increased by 39% in EX (PRE, 217 ± 88 mL·min; POST, 302 ± 167 mL·min) compared with CON (PRE, 188 ± 54 mL·min; POST, 184 ± 44 mL·min), P < 0.05. EX muscle oxidative capacity (kPCr) improved by 40% (PRE, 1.60 ± 0.57 min; POST, 2.25 ± 0.80 min) compared with CON (PRE, 1.69 ± 0.28 min; POST, 1.76 ± 0.52 min), P < 0.05. V˙O2peak increased by 9% for EX (PRE, 19.0 ± 3.1 mL·kg·min; POST, 20.8 ± 2.9 mL·kg·min) compared with a 7% loss in CON (PRE, 21.9 ± 3.6 mL·kg·min; POST, 20.4 ± 3.5 mL·kg·min), P < 0.05. CONCLUSION Moderate aerobic exercise significantly improved microvascular function of the leg in older adults.
Collapse
Affiliation(s)
- David M Hurley
- Department of Radiology, Michigan State University, East Lansing, MI
| | - Ewan R Williams
- Sport and Health Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Jeff M Cross
- Department of Radiology, Michigan State University, East Lansing, MI
| | | | - Ronald A Meyer
- Department of Physiology, Michigan State University, East Lansing, MI
| | - George S Abela
- Department of Medicine, Michigan State University, East Lansing, MI
| | - Jill M Slade
- Department of Radiology, Michigan State University, East Lansing, MI
| |
Collapse
|
11
|
Macdonald JA, Corrado PA, Nguyen SM, Johnson KM, Francois CJ, Magness RR, Shah DM, Golos TG, Wieben O. Uteroplacental and Fetal 4D Flow MRI in the Pregnant Rhesus Macaque. J Magn Reson Imaging 2018; 49:534-545. [PMID: 30102431 DOI: 10.1002/jmri.26206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 05/15/2018] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Pregnancy complications are often associated with poor uteroplacental vascular adaptation and standard diagnostics are unable to reliably quantify flow in all uteroplacental vessels and have poor sensitivity early in gestation. PURPOSE To investigate the feasibility of using 4D flow MRI to assess total uteroplacental blood flow in pregnant rhesus macaques as a precursor to human studies. STUDY TYPE Retrospective feasibility study. ANIMAL MODEL Fifteen healthy, pregnant rhesus macaques ranging from the 1st trimester to 3rd trimester of gestation. FIELD STRENGTH/SEQUENCE Abdominal 4D flow MRI was performed on a 3.0T scanner with a radially undersampled phase contrast (PC) sequence. Reference ferumoxytol-enhanced angiograms were acquired with a 3D ultrashort echo time sequence with a center-out radial trajectory. ASSESSMENT Repeatability of flow measurements was assessed with scans performed same-day and on consecutive days in the uterine arteries and ovarian veins. In-flow was compared against out-flow in the uterus, umbilical cord, and fetal heart with a conservation of mass analysis. Conspicuity of uteroplacental vessels was qualitatively compared between PC angiograms derived from 4D flow data and ferumoxytol-enhanced angiograms. STATISTICAL TESTS Bland-Altman analysis was used to quantify same-day and consecutive-day repeatability. RESULTS Same-day flow measurements showed an average difference between scans of 13% in both the uterine arteries and ovarian veins, while consecutive-day measurements showed average differences of 22% and 24%, respectively. Comparisons of in-flow and out-flow showed average differences of 15% in the uterus, 8% in fetal heart, and 15% in the umbilical cord. PC angiograms showed similar depiction of main uteroplacental vessels as high-resolution, ferumoxytol-enhanced angiograms. DATA CONCLUSION 4D flow MRI could be used in the rhesus macaque for repeatable flow measurements in the uteroplacental and fetal vasculature, setting the stage for future human studies. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:534-545.
Collapse
Affiliation(s)
- Jacob A Macdonald
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Philip A Corrado
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Sydney M Nguyen
- Wisconsin National Primate Center, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | | | - Ronald R Magness
- Department of Obstetrics & Gynecology, University of South Florida, Tampa, Florida, USA
| | - Dinesh M Shah
- Department of Obstetrics & Gynecology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Thaddeus G Golos
- Wisconsin National Primate Center, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Department of Comparative Biosciences, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Oliver Wieben
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| |
Collapse
|
12
|
Stacy MR, Caracciolo CM, Qiu M, Pal P, Varga T, Constable RT, Sinusas AJ. Comparison of regional skeletal muscle tissue oxygenation in college athletes and sedentary control subjects using quantitative BOLD MR imaging. Physiol Rep 2017; 4:4/16/e12903. [PMID: 27535483 PMCID: PMC5002911 DOI: 10.14814/phy2.12903] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 07/28/2016] [Indexed: 11/24/2022] Open
Abstract
Blood oxygen level‐dependent (BOLD) magnetic resonance (MR) imaging permits noninvasive assessment of tissue oxygenation. We hypothesized that BOLD imaging would allow for regional evaluation of differences in skeletal muscle oxygenation between athletes and sedentary control subjects, and dynamic BOLD responses to ischemia (i.e., proximal cuff occlusion) and reactive hyperemia (i.e., rapid cuff deflation) would relate to lower extremity function, as assessed by jumping ability. College football athletes (linemen, defensive backs/wide receivers) were compared to sedentary healthy controls. BOLD signal of the gastrocnemius, soleus, anterior tibialis, and peroneus longus was assessed for peak hyperemic value (PHV), time to peak (TTP), minimum ischemic value (MIV), and time to recovery (TTR). Significantly higher PHVs were identified in athletes versus controls for the gastrocnemius (linemen, 15.8 ± 9.1%; defensive backs/wide receivers, 17.9 ± 5.1%; controls, 7.4 ± 3.5%), soleus (linemen, 25.9 ± 11.5%; backs/receivers, 22.0 ± 9.4%; controls, 12.9 ± 5.8%), and anterior tibialis (linemen, 12.8 ± 5.3%; backs/receivers, 12.6 ± 3.9%; controls, 7.7 ± 4.0%), whereas no differences in PHV were found for the peroneus longus (linemen, 14.1 ± 6.9%; backs/receivers, 11.7 ± 4.6%; controls, 9.0 ± 4.9%). In all subject groups, the gastrocnemius and soleus muscles exhibited the lowest MIVs during cuff occlusion. No differences in TTR were found between muscles for any subject group. PHV of the gastrocnemius muscle was significantly and positively related to maximal vertical (r = 0.56, P = 0.002) and broad jump (r = 0.47, P = 0.01). These results suggest that BOLD MR imaging is a useful noninvasive tool for evaluating differences in tissue oxygenation of specific muscles between active and sedentary individuals, and peak BOLD responses may relate to functional capacity.
Collapse
Affiliation(s)
- Mitchel R Stacy
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | | | - Maolin Qiu
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Prasanta Pal
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Tyler Varga
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Robert Todd Constable
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut
| | - Albert J Sinusas
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| |
Collapse
|
13
|
Roubille F, Fischer K, Guensch DP, Tardif JC, Friedrich MG. Impact of hyperventilation and apnea on myocardial oxygenation in patients with obstructive sleep apnea – An oxygenation-sensitive CMR study. J Cardiol 2017; 69:489-494. [DOI: 10.1016/j.jjcc.2016.03.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 03/06/2016] [Accepted: 03/22/2016] [Indexed: 11/30/2022]
|
14
|
Towse TF, Elder CP, Bush EC, Klockenkemper SW, Bullock JT, Dortch RD, Damon BM. Post-contractile BOLD contrast in skeletal muscle at 7 T reveals inter-individual heterogeneity in the physiological responses to muscle contraction. NMR IN BIOMEDICINE 2016; 29:1720-1728. [PMID: 27753155 PMCID: PMC6594689 DOI: 10.1002/nbm.3593] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/29/2016] [Accepted: 07/06/2016] [Indexed: 05/13/2023]
Abstract
Muscle blood oxygenation-level dependent (BOLD) contrast is greater in magnitude and potentially more influenced by extravascular BOLD mechanisms at 7 T than it is at lower field strengths. Muscle BOLD imaging of muscle contractions at 7 T could, therefore, provide greater or different contrast than at 3 T. The purpose of this study was to evaluate the feasibility of using BOLD imaging at 7 T to assess the physiological responses to in vivo muscle contractions. Thirteen subjects (four females) performed a series of isometric contractions of the calf muscles while being scanned in a Philips Achieva 7 T human imager. Following 2 s maximal isometric plantarflexion contractions, BOLD signal transients ranging from 0.3 to 7.0% of the pre-contraction signal intensity were observed in the soleus muscle. We observed considerable inter-subject variability in both the magnitude and time course of the muscle BOLD signal. A subset of subjects (n = 7) repeated the contraction protocol at two different repetition times (TR : 1000 and 2500 ms) to determine the potential of T1 -related inflow effects on the magnitude of the post-contractile BOLD response. Consistent with previous reports, there was no difference in the magnitude of the responses for the two TR values (3.8 ± 0.9 versus 4.0 ± 0.6% for TR = 1000 and 2500 ms, respectively; mean ± standard error). These results demonstrate that studies of the muscle BOLD responses to contractions are feasible at 7 T. Compared with studies at lower field strengths, post-contractile 7 T muscle BOLD contrast may afford greater insight into microvascular function and dysfunction.
Collapse
Affiliation(s)
- Theodore F. Towse
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Physical Medicine and Rehabilitation, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Christopher P. Elder
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Emily C. Bush
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Samuel W. Klockenkemper
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jared T. Bullock
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Richard D. Dortch
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bruce M. Damon
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University School of Engineering, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| |
Collapse
|
15
|
Huelnhagen T, Hezel F, Serradas Duarte T, Pohlmann A, Oezerdem C, Flemming B, Seeliger E, Prothmann M, Schulz-Menger J, Niendorf T. Myocardial effective transverse relaxation time T2* Correlates with left ventricular wall thickness: A 7.0 T MRI study. Magn Reson Med 2016; 77:2381-2389. [PMID: 27342430 DOI: 10.1002/mrm.26312] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/23/2016] [Accepted: 05/25/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE Myocardial effective relaxation time T2* is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influence T2*. To this end, this study investigates the relationship between T2* and cardiac macromorphology given by left ventricular (LV) wall thickness and left ventricular radius, and provides interpretation of the results in the physiological context. METHODS High spatio-temporally resolved myocardial CINE T2* mapping was performed in 10 healthy volunteers using a 7.0 Tesla (T) full-body MRI system. Ventricular septal wall thickness, left ventricular inner radius, and T2* were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase-resolved magnetic field maps. RESULTS Ventricular septal T2* changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness and T2* showed a significant positive correlation, whereas the inner LV radius and T2* were negatively correlated. The effect of macroscopic magnetic field gradients on T2* can be considered minor in the ventricular septum. CONCLUSION Our findings suggest that myocardial T2* is related to tissue blood volume fraction. Temporally resolved T2* mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo. Magn Reson Med 77:2381-2389, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Teresa Serradas Duarte
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Bert Flemming
- Institute of Physiology, Charité University Medicine, Berlin, Germany
| | - Erdmann Seeliger
- Institute of Physiology, Charité University Medicine, Berlin, Germany
| | - Marcel Prothmann
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Jeanette Schulz-Menger
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| |
Collapse
|
16
|
Rajagopalan S, Shin T. Being BOLD in Critical Limb Ischemia. J Am Coll Cardiol 2016; 67:432-434. [PMID: 26821632 DOI: 10.1016/j.jacc.2015.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 11/04/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Sanjay Rajagopalan
- Division of Cardiovascular Medicine, University of Maryland School of Medicine, Baltimore, Maryland.
| | - Taehoon Shin
- Department of Radiology, University of Maryland School of Medicine, Baltimore, Maryland
| |
Collapse
|
17
|
Stacy MR, Qiu M, Papademetris X, Caracciolo CM, Constable RT, Sinusas AJ. Application of BOLD Magnetic Resonance Imaging for Evaluating Regional Volumetric Foot Tissue Oxygenation: A Feasibility Study in Healthy Volunteers. Eur J Vasc Endovasc Surg 2016; 51:743-9. [PMID: 26970710 DOI: 10.1016/j.ejvs.2016.02.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/09/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE/BACKGROUND To evaluate the feasibility and repeatability of applying blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in the feet to quantify regional dynamic changes in tissue oxygenation during proximal cuff occlusion and reactive hyperemia. METHODS Ten healthy male subjects underwent BOLD and T1-weighted imaging of the feet on two separate occasions, using a 3-T scanner. Dynamic changes in BOLD signal intensity were assessed before and during proximal cuff occlusion of the thigh and during reactive hyperemia, and BOLD time course data were evaluated for the time-to-half ischemic minimum, minimum ischemic value, peak hyperemic value, time-to-peak hyperemia, time-to-half peak hyperemia, and end value. T1-weighted images were used for segmentation of volumes of interest (VOI) in anatomical regions of the foot (heel, toes, dorsal foot, medial and lateral plantar foot). Repeatability of vascular responses was assessed for each foot VOI using semiautomated image registration and quantification of serial BOLD images. RESULTS The heel VOI demonstrated a significantly higher peak hyperemic response, expressed as percent change from baseline BOLD signal intensity, compared with all other VOIs of the foot (heel, 7.4 ± 1.2%; toes, 5.6 ± 0.8%; dorsal foot, 5.7 ± 1.6%; medial plantar, 5.6 ± 1.7%; lateral plantar, 5.6 ± 1.5% [p < .05]). Additionally, the lateral plantar VOI had a significantly lower terminal signal intensity value (i.e., end value) when compared with all foot VOIs (p < .05). BOLD MRI was repeatable between visits in all foot VOIs, with no significant differences between study visits for any of the evaluated functional indices. CONCLUSION BOLD MRI offers a repeatable technique for volumetric assessment of regional foot tissue oxygenation. Future application of BOLD imaging in the feet of patients with peripheral vascular disease may permit serial evaluation of regional tissue oxygenation and allow for improved assessment of therapeutic interventions targeting specific sites of the foot.
Collapse
Affiliation(s)
- M R Stacy
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
| | - M Qiu
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - X Papademetris
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA; Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT, USA
| | - C M Caracciolo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - R T Constable
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA; Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT, USA; Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - A J Sinusas
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA; Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
| |
Collapse
|
18
|
Larsen RG, Hirata RP, Madzak A, Frøkjær JB, Graven-Nielsen T. Eccentric exercise slows in vivo microvascular reactivity during brief contractions in human skeletal muscle. J Appl Physiol (1985) 2015; 119:1272-81. [DOI: 10.1152/japplphysiol.00563.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022] Open
Abstract
Unaccustomed exercise involving eccentric contractions results in muscle soreness and an overall decline in muscle function, however, little is known about the effects of eccentric exercise on microvascular reactivity in human skeletal muscle. Fourteen healthy men and women performed eccentric contractions of the dorsiflexor muscles in one leg, while the contralateral leg served as a control. At baseline, and 24 and 48 h after eccentric exercise, the following were acquired bilaterally in the tibialis anterior muscle: 1) transverse relaxation time (T2)-weighted magnetic resonance images to determine muscle cross-sectional area (mCSA) and T2; 2) blood oxygen level-dependent (BOLD) images during and following brief, maximal voluntary contractions (MVC) to monitor the hyperemic responses with participants positioned supine in a 3T magnet; 3) muscle strength; and 4) pain pressure threshold. Compared with the control leg, eccentric exercise resulted in soreness, decline in strength (∼20%), increased mCSA (∼7%), and prolonged T2 (∼7%) at 24 and 48 h ( P < 0.05). The BOLD response to a brief MVC was altered 24 and 48 h after eccentric exercise, such that time-to-peak (∼35%, P < 0.05) and time-to-half-recovery (∼23%, P < 0.05) were prolonged. The altered contraction-induced hyperemic response suggests slowed microvascular reactivity and altered matching of O2 delivery to O2 utilization within muscle tissue showing signs of muscle damage. These changes in microvascular regulation after eccentric exercise may impede rapid adjustments in muscle blood flow at exercise onset and during activities involving brief bursts of muscle activation, which may impair O2 delivery and contribute to reduced muscle function after eccentric exercise.
Collapse
Affiliation(s)
- Ryan G. Larsen
- Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, Alborg, Denmark
| | - Rogerio P. Hirata
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Alborg, Denmark
| | - Adnan Madzak
- Department of Radiology, Aalborg University Hospital, Aalborg, Denmark; and
| | - Jens B. Frøkjær
- Department of Radiology, Aalborg University Hospital, Aalborg, Denmark; and
- Department of Clinical Medicine, Aalborg University, Alborg, Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Alborg, Denmark
| |
Collapse
|
19
|
Buck AKW, Elder CP, Donahue MJ, Damon BM. Matching of postcontraction perfusion to oxygen consumption across submaximal contraction intensities in exercising humans. J Appl Physiol (1985) 2015; 119:280-9. [PMID: 26066829 DOI: 10.1152/japplphysiol.01027.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 06/08/2015] [Indexed: 12/23/2022] Open
Abstract
Studying the magnitude and kinetics of blood flow, oxygen extraction, and oxygen consumption at exercise onset and during the recovery from exercise can lead to insights into both the normal control of metabolism and blood flow and the disturbances to these processes in metabolic and cardiovascular diseases. The purpose of this study was to examine the on- and off-kinetics for oxygen delivery, extraction, and consumption as functions of submaximal contraction intensity. Eight healthy subjects performed four 1-min isometric dorsiflexion contractions, with two at 20% MVC and two at 40% MVC. During one contraction at each intensity, relative perfusion changes were measured by using arterial spin labeling, and the deoxyhemoglobin percentage (%HHb) was estimated using the spin- and gradient-echo sequence and a previously published empirical calibration. For the whole group, the mean perfusion did not increase during contraction. The %HHb increased from ∼28 to 38% during contractions of each intensity, with kinetics well described by an exponential function and mean response times (MRTs) of 22.7 and 21.6 s for 20 and 40% MVC, respectively. Following contraction, perfusion increased ∼2.5-fold. The %HHb, oxygen consumption, and perfusion returned to precontraction levels with MRTs of 27.5, 46.4, and 50.0 s, respectively (20% MVC), and 29.2, 75.3, and 86.0 s, respectively (40% MVC). These data demonstrate in human subjects the varied recovery rates of perfusion and oxygen consumption, along with the similar rates of %HHb recovery, across these exercise intensities.
Collapse
Affiliation(s)
- Amanda K W Buck
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Christopher P Elder
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
| | - Manus J Donahue
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Department of Psychiatry, Vanderbilt University, Nashville, Tennessee; Department of Neurology, Vanderbilt University, Nashville, Tennessee; Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee; and
| | - Bruce M Damon
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee; Department of Molecular Physiology and Biophysics Vanderbilt University, Nashville, Tennessee
| |
Collapse
|
20
|
Nishii T, Kono AK, Nishio M, Kyotani K, Nishiyama K, Sugimura K. Dynamic Blood Oxygen Level-dependent MR Imaging of Muscle: Comparison of Postocclusive Reactive Hyperemia in Young Smokers and Nonsmokers. Magn Reson Med Sci 2015; 14:275-83. [PMID: 25994035 DOI: 10.2463/mrms.2014-0105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The role of early stage functional assessment of muscle blood flow response (MFR) by dynamic muscle blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging is unknown. We investigated the effect of smoking on vascular function according to MFR derived from dynamic muscle BOLD MR imaging during postocclusive reactive hyperemia in young smokers and nonsmokers. METHODS Sixteen healthy male volunteers (8 smokers, 8 nonsmokers; mean age, 30.4 ± 4.6 years) underwent BOLD MR imaging of the left calf muscle. During reactive hyperemia provoked by a cuff-compression technique, we measured muscle BOLD (mB) using a 3-tesla single-shot multi-echo gradient-echo echo-planar imaging sequence. The 2 key mB variables in the reactive hyperemic phase that we studied were times to half hyperemic peak (T(1/2peak)) and peak (TTP), each measured from cuff deflation. We used the Welch test to assess differences in these between smokers and nonsmokers. RESULTS T(1/2peak) and TTP were significantly longer in smokers (P < 0.05) in reactive hyperemia. T(1/2peak) was 13.8 ± 5.4 s in smokers and 7.6 ± 1.5 s in nonsmokers, and TTP was 67.5 ± 18.8 s in smokers and 45.4 ± 7.1 s in nonsmokers. CONCLUSION Dynamic BOLD MR imaging of calf muscle during postocclusive reactive hyperemia demonstrated statistically significant differences in T(1/2peak) and TTP between young smokers and nonsmokers, indicating the presence of early stage smoking-related deterioration in MFR.
Collapse
Affiliation(s)
- Tatsuya Nishii
- Department of Radiology, Kobe University Graduate School of Medicine
| | | | | | | | | | | |
Collapse
|
21
|
Towse TF, Childs BT, Sabin SA, Bush EC, Elder CP, Damon BM. Comparison of muscle BOLD responses to arterial occlusion at 3 and 7 Tesla. Magn Reson Med 2015; 75:1333-40. [PMID: 25884888 DOI: 10.1002/mrm.25562] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/21/2014] [Accepted: 11/12/2014] [Indexed: 12/16/2022]
Abstract
PURPOSE The purpose of this study was to determine the feasibility of muscle BOLD (mBOLD) imaging at 7 Tesla (T) by comparing the changes in R2* of muscle at 3 and 7T in response to a brief period of tourniquet-induced ischemia. METHODS Eight subjects (three male), aged 29.5 ± 6.1 years (mean ± standard deviation, SD), 167.0 ± 10.6 cm tall with a body mass of 62.0 ± 18.0 kg, participated in the study. Subjects reported to the lab on four separate occasions including a habituation session, two MRI scans, and in a subset of subjects, a session during which changes in blood flow and blood oxygenation were quantified using Doppler ultrasound (U/S) and near-infrared spectroscopy (NIRS) respectively. For statistical comparisons between 3 and 7T, R2* rate constants were calculated as R2* = 1/T2*. RESULTS The mean preocclusion R2* value was greater at 7T than at 3T (60.16 ± 2.95 vs. 35.17 ± 0.35 s(-1), respectively, P < 0.001). Also, the mean ΔR2 *END and ΔR2*POST values were greater for 7T than for 3T (-2.36 ± 0.25 vs. -1.24 ± 0.39 s(-1), respectively, Table 1). CONCLUSION Muscle BOLD contrast at 7T is as much as six-fold greater than at 3T. In addition to providing greater SNR and CNR, 7T mBOLD studies may offer further advantages in the form of greater sensitivity to pathological changes in the muscle microcirculation.
Collapse
Affiliation(s)
- Theodore F Towse
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Benjamin T Childs
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Shea A Sabin
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Emily C Bush
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Christopher P Elder
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Bruce M Damon
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
22
|
Decorte N, Buehler T, Caldas de Almeida Araujo E, Vignaud A, Carlier PG. Noninvasive estimation of oxygen consumption in human calf muscle through combined NMR measurements of ASL perfusion and T₂ oxymetry. J Vasc Res 2014; 51:360-8. [PMID: 25531648 DOI: 10.1159/000368194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 09/03/2014] [Indexed: 11/19/2022] Open
Abstract
The objective of this work was to demonstrate the feasibility of measuring muscle O2 consumption (V˙O2) noninvasively with a combination of functional nuclear magnetic resonance (NMR) imaging methods, and to verify that changes in muscle V˙O2 can be detected with a temporal resolution compatible with physiological investigation and patient ease. T2-based oxymetry of arterial and venous blood was combined with the arterial-spin labeling (ASL)-based determination of muscle perfusion. These measurements were performed on 8 healthy volunteers under normoxic and hypoxic conditions in order to assess the sensitivity of measurements over a range of saturation values. Blood samples were drawn simultaneously and used to titrate blood T2 measurements versus hemoglobin O2 saturation (%HbO2) in vitro. The in vitro calibration curve of blood T2 fitted very well with the %HbO2 (r(2): 0.95). The in vivo venous T2 measurements agreed well with the in vitro measurements (intraclass correlation coefficient 0.82, 95% confidence interval 0.61-0.91). Oxygen extraction at rest decreased in the calf muscles subjected to hypoxia (p = 0.031). The combination of unaltered muscle perfusion and pinched arteriovenous O2 difference (p = 0.038) pointed towards a reduced calf muscle V˙O2 during transient hypoxia (p = 0.018). The results of this pilot study confirmed that muscle O2 extraction and V˙O2 can be estimated noninvasively using a combination of functional NMR techniques. Further studies are needed to confirm the usefulness in a larger sample of volunteers and patients.
Collapse
|
23
|
|
24
|
Ma HT, Griffith JF, Ye C, Yeung DK, Xing X, Leung PC, Yuan J. BOLD effect on calf muscle groups in elderly females with different bone mineral density. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2014; 2014:5607-5610. [PMID: 25571266 DOI: 10.1109/embc.2014.6944898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This study examined the BOLD effect on calf muscles in elderly subjects with different bone mineral density. The purpose was to investigate the oxygenation characteristics in different calf muscle groups for the elderly females and compare the muscle oxygenation among groups with different bone mineral density. Temporary vascular occlusion was induced with air-cuff compression of the thigh and BOLD-MRI data curve was fitted to derive quantitative parameters. Three muscle groups, gastrocnemius muscle (lateral head), soleus muscle, and tibialis anterior muscle, were investigated individually. Quantitative CT measurement was conducted on each subject, based on which subjects were classified into normal, osteopenia, and osteoporosis groups. The BOLD signal in soleus muscle showed the lowest minimum ischemic value during ischemia and the steepest slope during hyperemia. As soleus muscle is mainly composed by slow-twitch oxidative muscle fibers, current results may be due to a higher vascular bed density and better endothelial function in such muscle. By t-test, the half-life of the BOLD signal decay during ischemia in both gastrocnemius and soleus muscles was significantly prolonged in osteoporosis group, indicating a degenerated muscular oxygen metabolic capacity in osteoporotic patients.
Collapse
|
25
|
Does Helium Act on Vascular Endothelial Function in Humans? Anesthesiology 2013; 119:488. [DOI: 10.1097/aln.0b013e3182987cd2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
26
|
Detailing magnetic field strength dependence and segmental artifact distribution of myocardial effective transverse relaxation rate at 1.5, 3.0, and 7.0 T. Magn Reson Med 2013; 71:2224-30. [DOI: 10.1002/mrm.24856] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/04/2013] [Accepted: 06/05/2013] [Indexed: 12/12/2022]
|
27
|
Friedrich MG, Karamitsos TD. Oxygenation-sensitive cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2013; 15:43. [PMID: 23706167 PMCID: PMC3681671 DOI: 10.1186/1532-429x-15-43] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 04/29/2013] [Indexed: 12/30/2022] Open
Abstract
Oxygenation-sensitive cardiovascular magnetic resonance (CMR) is a non-contrast technique that allows the non-invasive assessment of myocardial oxygenation. It capitalizes on the fact that deoxygenated hemoglobin in blood can act as an intrinsic contrast agent, changing proton signals in a fashion that can be imaged to reflect the level of blood oxygenation. Increases in O(2) saturation increase the BOLD imaging signal (T2 or T2*), whereas decreases diminish it. This review presents the basic concepts and limitations of the BOLD technique, and summarizes the preclinical and clinical studies in the assessment of myocardial oxygenation with a focus on recent advances. Finally, it provides future directions and a brief look at emerging techniques of this evolving CMR field.
Collapse
Affiliation(s)
- Matthias G Friedrich
- Montreal Heart Institute, Departments of Cardiology and Radiology, Université de Montréal, Montreal, QC, Canada
- Departments of Cardiac Sciences and Radiology, University of Calgary, Calgary, Canada
| | - Theodoros D Karamitsos
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| |
Collapse
|
28
|
Hezel F, Thalhammer C, Waiczies S, Schulz-Menger J, Niendorf T. High spatial resolution and temporally resolved T2* mapping of normal human myocardium at 7.0 Tesla: an ultrahigh field magnetic resonance feasibility study. PLoS One 2012; 7:e52324. [PMID: 23251708 PMCID: PMC3522647 DOI: 10.1371/journal.pone.0052324] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/16/2012] [Indexed: 11/19/2022] Open
Abstract
Myocardial tissue characterization using T(2)(*) relaxation mapping techniques is an emerging application of (pre)clinical cardiovascular magnetic resonance imaging. The increase in microscopic susceptibility at higher magnetic field strengths renders myocardial T(2)(*) mapping at ultrahigh magnetic fields conceptually appealing. This work demonstrates the feasibility of myocardial T(2)(*) imaging at 7.0 T and examines the applicability of temporally-resolved and high spatial resolution myocardial T(2)(*) mapping. In phantom experiments single cardiac phase and dynamic (CINE) gradient echo imaging techniques provided similar T(2)(*) maps. In vivo studies showed that the peak-to-peak B(0) difference following volume selective shimming was reduced to approximately 80 Hz for the four chamber view and mid-ventricular short axis view of the heart and to 65 Hz for the left ventricle. No severe susceptibility artifacts were detected in the septum and in the lateral wall for T(2)(*) weighting ranging from TE = 2.04 ms to TE = 10.2 ms. For TE >7 ms, a susceptibility weighting induced signal void was observed within the anterior and inferior myocardial segments. The longest T(2)(*) values were found for anterior (T(2)(*) = 14.0 ms), anteroseptal (T(2)(*) = 17.2 ms) and inferoseptal (T(2)(*) = 16.5 ms) myocardial segments. Shorter T(2)(*) values were observed for inferior (T(2)(*) = 10.6 ms) and inferolateral (T(2)(*) = 11.4 ms) segments. A significant difference (p = 0.002) in T(2)(*) values was observed between end-diastole and end-systole with T(2)(*) changes of up to approximately 27% over the cardiac cycle which were pronounced in the septum. To conclude, these results underscore the challenges of myocardial T(2)(*) mapping at 7.0 T but demonstrate that these issues can be offset by using tailored shimming techniques and dedicated acquisition schemes.
Collapse
Affiliation(s)
- Fabian Hezel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Christof Thalhammer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
- Experimental and Clinical Research Center, a Joint Cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Campus Berlin Buch, Berlin, Germany
| | - Jeanette Schulz-Menger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
- Experimental and Clinical Research Center, a Joint Cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Campus Berlin Buch, Berlin, Germany
- Department of Cardiology and Nephrology, HELIOS Klinikum Berlin Buch, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
- Experimental and Clinical Research Center, a Joint Cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Campus Berlin Buch, Berlin, Germany
| |
Collapse
|
29
|
Yeung DK, Griffith JF, Li AF, Ma HT, Yuan J. Air pressure-induced susceptibility changes in vascular reactivity studies using BOLD MRI. J Magn Reson Imaging 2012; 38:976-80. [PMID: 23172781 DOI: 10.1002/jmri.23926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 10/01/2012] [Indexed: 11/07/2022] Open
Affiliation(s)
- David K.W. Yeung
- Department of Imaging and Interventional Radiology; Faculty of Medicine; Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong SAR China
| | - James F. Griffith
- Department of Imaging and Interventional Radiology; Faculty of Medicine; Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong SAR China
| | - Alvin F.W. Li
- Department of Imaging and Interventional Radiology; Faculty of Medicine; Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong SAR China
| | - Heather T. Ma
- Department of Electronic and Information Engineering; Harbin Institute of Technology Shenzhen Graduate School; Shenzhen China
| | - Jing Yuan
- Department of Imaging and Interventional Radiology; Faculty of Medicine; Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong SAR China
| |
Collapse
|
30
|
Flammer AJ, Anderson T, Celermajer DS, Creager MA, Deanfield J, Ganz P, Hamburg NM, Lüscher TF, Shechter M, Taddei S, Vita JA, Lerman A. The assessment of endothelial function: from research into clinical practice. Circulation 2012; 126:753-67. [PMID: 22869857 DOI: 10.1161/circulationaha.112.093245] [Citation(s) in RCA: 827] [Impact Index Per Article: 68.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Andreas J Flammer
- Division of Cardiovascular Diseases, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Jacobi B, Bongartz G, Partovi S, Schulte AC, Aschwanden M, Lumsden AB, Davies MG, Loebe M, Noon GP, Karimi S, Lyo JK, Staub D, Huegli RW, Bilecen D. Skeletal muscle BOLD MRI: from underlying physiological concepts to its usefulness in clinical conditions. J Magn Reson Imaging 2012; 35:1253-65. [PMID: 22588992 DOI: 10.1002/jmri.23536] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Blood oxygenation-level dependent (BOLD) MRI has gained particular attention in functional brain imaging studies, where it can be used to localize areas of brain activation with high temporal resolution. To a higher degree than in the brain, skeletal muscles show extensive but transient alterations of blood flow between resting and activation state. Thus, there has been interest in the application of the BOLD effect in studying the physiology of skeletal muscles (healthy and diseased) and its possible application to clinical practice. This review outlines the potential of skeletal muscle BOLD MRI as a diagnostic tool for the evaluation of physiological and pathological alterations in the peripheral limb perfusion, such as in peripheral arterial occlusive disease. Moreover, current knowledge is summarized regarding the complex mechanisms eliciting BOLD effect in skeletal muscle. We describe technical fundaments of the procedure that should be taken into account when performing skeletal muscle BOLD MRI, including the most often applied paradigms to provoke BOLD signal changes and key parameters of the resulting time courses. Possible confounding effects in muscle BOLD imaging studies, like age, muscle fiber type, training state, and drug effects are also reviewed in detail.
Collapse
Affiliation(s)
- Bjoern Jacobi
- Department of Radiology, University Hospital Bruderholz, Bruderholz, Basel, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Andreas M, Schmid AI, Doberer D, Schewzow K, Weisshaar S, Heinze G, Bilban M, Moser E, Wolzt M. Heme arginate improves reperfusion patterns after ischemia: a randomized, placebo-controlled trial in healthy male subjects. J Cardiovasc Magn Reson 2012; 14:55. [PMID: 22857721 PMCID: PMC3438022 DOI: 10.1186/1532-429x-14-55] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Accepted: 07/09/2012] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED BACKGROUND Heme arginate can induce heme oxygenase-1 to protect tissue against ischemia-reperfusion injury. Blood oxygen level dependent (BOLD) functional magnetic resonance imaging measures changes in tissue oxygenation with a high spatial and temporal resolution. BOLD imaging was applied to test the effect of heme arginate on experimental ischemia reperfusion injury in the calf muscles. METHODS A two period, controlled, observer blinded, crossover trial was performed in 12 healthy male subjects. Heme arginate (1 mg/kg body weight) or placebo were infused 24 h prior to a 20 min leg ischemia induced by a thigh cuff. 3 Tesla BOLD-imaging of the calf was performed and signal time courses from soleus, gastrocnemius and tibialis anterior muscle were available from 11 participants for technical reasons. RESULTS Peak reactive hyperemia signal of the musculature was significantly increased and occurred earlier after heme arginate compared to placebo (106.2 ± 0.6% at 175 ± 16s vs. 104.5 ± 0.6% at 221 ± 19s; p = 0.025 for peak reperfusion and p = 0.012 for time to peak). CONCLUSIONS A single high dose of heme arginate improves reperfusion patterns during ischemia reperfusion injury in humans. BOLD sensitive, functional MRI is applicable for the assessment of experimental ischemia reperfusion injury in skeletal muscle.
Collapse
Affiliation(s)
- Martin Andreas
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Albrecht Ingo Schmid
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Daniel Doberer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Kiril Schewzow
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Stefan Weisshaar
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Georg Heinze
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Martin Bilban
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
33
|
Partovi S, Karimi S, Jacobi B, Schulte AC, Aschwanden M, Zipp L, Lyo JK, Karmonik C, Müller-Eschner M, Huegli RW, Bongartz G, Bilecen D. Clinical implications of skeletal muscle blood-oxygenation-level-dependent (BOLD) MRI. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2012; 25:251-61. [PMID: 22374263 DOI: 10.1007/s10334-012-0306-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 01/24/2023]
Abstract
Blood-oxygenation-level-dependent (BOLD) contrast in magnetic resonance (MR) imaging of skeletal muscle mainly depends on changes of oxygen saturation in the microcirculation. In recent years, an increasing number of studies have evaluated the clinical relevance of skeletal muscle BOLD MR imaging in vascular diseases, such as peripheral arterial occlusive disease, diabetes mellitus, and chronic compartment syndrome. BOLD imaging combines the advantages of MR imaging, i.e., high spatial resolution, no exposure to ionizing radiation, with functional information of local microvascular perfusion. Due to intrinsic contrast provoked via changes in hemoglobin oxygen saturation, it is a safe and easy applicable procedure on standard whole-body MR devices. Therefore, BOLD MR imaging of skeletal muscle is a potential new diagnostic tool in the clinical evaluation of vascular, inflammatory, and muscular pathologies. Our review focuses on the current evidence concerning the use of BOLD MR imaging of skeletal muscle under pathological conditions and highlights ways for future clinical and scientific applications.
Collapse
Affiliation(s)
- Sasan Partovi
- Department of Radiology, University Hospital Bruderholz, Basel, Switzerland.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Slade JM, Towse TF, Gossain VV, Meyer RA. Peripheral microvascular response to muscle contraction is unaltered by early diabetes but decreases with age. J Appl Physiol (1985) 2011; 111:1361-71. [PMID: 21799123 DOI: 10.1152/japplphysiol.00009.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Long-term or untreated diabetes leads to micro- and macrovascular complications. However, there are few tests to evaluate microvascular function. A postcontraction blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) technique was exploited to measure peripheral microvascular function in diabetics and healthy controls matched with respect to age, body mass index, and physical activity. Postcontraction BOLD microvascular response was measured following 1-s maximal isometric ankle dorsiflexion in individuals with diabetes mellitus type I [DMI, n = 15, age 33 ± 3 yr (means ± SE), median diabetes duration = 5.5 yr] and type II (DMII, n = 16, age 45 ± 2 yr, median duration = 2.4 yr); responses were compared with controls (CONI and CONII). Peripheral macrovascular function of the popliteal and tibial arteries was assessed during exercise hyperemia with phase contrast magnetic resonance angiography following repetitive exercise. There were no group differences as a result of diabetes in peripheral microvascular function (peak BOLD response: DMI = 2.04 ± 0.38% vs. CONI = 2.08 ± 0.48%; DMII = 0.93 ± 0.24% vs. CONII = 1.13 ± 0.24%; mean ± SE), but the BOLD response was significantly influenced by age (partial r = -0.384, P = 0.003), supporting its sensitivity as a measure of microvascular function. Eleven individuals had no microvascular BOLD response, including three diabetics with neuropathy and four controls with a family history of diabetes. There were no differences in peripheral macrovascular function between groups when assessing exercise hyperemia or the pulsitility and resistive indexes. Although the BOLD microvascular response was not impaired in early diabetes, these results encourage further investigation of muscle BOLD as it relates to peripheral microvascular health.
Collapse
Affiliation(s)
- Jill M Slade
- Dept. of Radiology, East Lansing, MI 48824, USA.
| | | | | | | |
Collapse
|
35
|
Rajagopalan S, Mihai G. Perspectives on optimizing trial design and endpoints in peripheral arterial disease: a case for imaging-based surrogates as endpoints of functional efficacy. Cardiol Clin 2011; 29:419-31. [PMID: 21803230 DOI: 10.1016/j.ccl.2011.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Surrogate endpoints are important for validation of mechanism, early proof of concept, and the rational design of clinical trials for regulatory approval of drugs. The recent failure of several drugs in peripheral arterial disease (PAD) and in atherosclerosis highlights the importance of understanding drug effect and is a clarion call for better endpoints. This review focuses on aspects relating to the current state of surrogate endpoints in PAD and reviews emerging endpoints using imaging approaches that may have the potential of improving study design in PAD.
Collapse
Affiliation(s)
- Sanjay Rajagopalan
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, 473 West 12 Avenue, Columbus, OH 43210, USA.
| | | |
Collapse
|
36
|
Sanchez OA, Copenhaver EA, Chance MA, Fowler MJ, Towse TF, Kent-Braun JA, Damon BM. Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner. Am J Physiol Heart Circ Physiol 2011; 301:H418-27. [PMID: 21572006 DOI: 10.1152/ajpheart.00060.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The purpose of this study was to determine whether there are differences in postisometric contraction blood volume and oxygenation responses among groups of type 2 diabetes mellitus (T2DM), obese, and lean individuals detectable using MRI. Eight T2DM patients were individually matched by age, sex, and race to non-T2DM individuals with similar body mass index (obese) and lean subjects. Functional MRI was performed using a dual-gradient-recalled echo, echo-planar imaging sequence with a repetition time of 1 s and at two echo times (TE = 6 and 46 ms). Data were acquired before, during, and after 10-s isometric dorsiflexion contractions performed at 50 and 100% of maximal voluntary contraction (MVC) force. MRI signal intensity (SI) changes from the tibialis anterior and extensor digitorum longus muscles were plotted as functions of time for each TE. From each time course, the difference between the minimum and the maximum postcontraction SI (ΔSI) were determined for TE = 6 ms (ΔSI(6)) and TE = 46 ms (ΔSI(46)), reflecting variations in blood volume and oxyhemoglobin saturation, respectively. Following 50% MVC contractions, the mean postcontraction ΔSI(6) values were similar in the three groups. Following MVC only, and in the EDL muscle only, T2DM and obese participants had ∼56% lower ΔSI(6) than the lean individuals. Also following MVC only, the ΔSI(46) response in the EDL was lower in T2DM subjects than in lean individuals. These data suggest that skeletal muscle small vessel impairment occurs in T2DM and body mass index-matched subjects, in muscle-specific and contraction intensity-dependent manners.
Collapse
Affiliation(s)
- Otto A Sanchez
- Institute of Imaging Science, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Sanchez OA, Copenhaver EA, Elder CP, Damon BM. Absence of a significant extravascular contribution to the skeletal muscle BOLD effect at 3 T. Magn Reson Med 2011; 64:527-35. [PMID: 20665796 DOI: 10.1002/mrm.22449] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Blood oxygenation level dependent (BOLD) contrast in skeletal may reflect the contributions of both intravascular and extravascular relaxation effects. The purpose of this study was to determine the significance of the extravascular BOLD effect in skeletal muscle at 3 T. In experiments, R(2)* was measured before and during arterial occlusion under the following conditions: (1) the leg extended and rotated (to vary the capillary orientation with respect to the amplitude of static field) and (2) with the blood's signal nulled using a multiecho vascular space occupancy experiment. In the leg rotation protocol, 3 min of arterial occlusion decreased oxyhemoglobin saturation from 67% to 45% and increased R(2)* from 34.2 to 36.6 sec(-1), but there was no difference in the R(2)* response to occlusion between the extended and rotated positions. Numerical simulations of intra- and extravascular BOLD effects corresponding to these conditions predicted that the intravascular BOLD contribution to the R(2)* change was always > 50 times larger than the extravascular BOLD contribution. Blood signal nulling eliminated the change in R(2)* caused by arterial occlusion. These data indicate that under these experimental conditions, the contribution of the extravascular BOLD effect to skeletal muscle R(2)* was too small to be practically important.
Collapse
Affiliation(s)
- Otto A Sanchez
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | | |
Collapse
|
38
|
Friedrich MG. Current status of cardiovascular magnetic resonance imaging in the assessment of coronary vasculature. Can J Cardiol 2010; 26 Suppl A:51A-55A. [PMID: 20386762 DOI: 10.1016/s0828-282x(10)71063-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
The present review describes the contributions of cardiovascular magnetic resonance (CMR) imaging to the assessment of coronary vasculature. It briefly describes various approaches and highlights the value of comprehensive CMR protocols. The limitations of coronary angiography for clinical decision-making and the additional value of plaque imaging and tissues characterization, as well as future directions of CMR and hybrid techniques for assessing microvascular function and myocardial oxygenation, are discussed.
Collapse
Affiliation(s)
- Matthias G Friedrich
- Stephenson Cardiovascular Magnetic Resonance Imaging Center, Libin Cardiovascular Institute of Alberta, University of Calgary & Foothills Medical Centre, Calgary, Alberta, Canada.
| |
Collapse
|
39
|
Vöhringer M, Flewitt JA, Green JD, Dharmakumar R, Wang J, Tyberg JV, Friedrich MG. Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation. J Cardiovasc Magn Reson 2010; 12:20. [PMID: 20356402 PMCID: PMC2861023 DOI: 10.1186/1532-429x-12-20] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 03/31/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As myocardial oxygenation may serve as a marker for ischemia and microvascular dysfunction, it could be clinically useful to have a non-invasive measure of changes in myocardial oxygenation. However, the impact of induced blood flow changes on oxygenation is not well understood. We used oxygenation-sensitive CMR to assess the relations between myocardial oxygenation and coronary sinus blood oxygen saturation (SvO2) and coronary blood flow in a dog model in which hyperemia was induced by intracoronary administration of vasodilators. RESULTS During administration of acetylcholine and adenosine, CMR signal intensity correlated linearly with simultaneously measured SvO2 (r2 = 0.74, P < 0.001). Both SvO2 and CMR signal intensity were exponentially related to coronary blood flow, with SvO2 approaching 87%. CONCLUSIONS Myocardial oxygenation as assessed with oxygenation-sensitive CMR imaging is linearly related to SvO2 and is exponentially related to vasodilator-induced increases of blood flow. Oxygenation-sensitive CMR may be useful to assess ischemia and microvascular function in patients. Its clinical utility should be evaluated.
Collapse
Affiliation(s)
- Matthias Vöhringer
- Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada
- Robert-Bosch-Krankenhaus, Stuttgart, Germany
| | - Jacqueline A Flewitt
- Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada
| | - Jordin D Green
- Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada
- Siemens Healthcare, Erlangen, Germany
| | | | - Jiun Wang
- Fu-Jen University Medical School, Hsinchuang, Taiwan
| | - John V Tyberg
- Department of Cardiac Sciences and Physiology/Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Matthias G Friedrich
- Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada
| |
Collapse
|
40
|
Langham MC, Floyd TF, Mohler ER, Magland JF, Wehrli FW. Evaluation of cuff-induced ischemia in the lower extremity by magnetic resonance oximetry. J Am Coll Cardiol 2010; 55:598-606. [PMID: 20152564 DOI: 10.1016/j.jacc.2009.08.068] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 08/20/2009] [Accepted: 08/30/2009] [Indexed: 01/17/2023]
Abstract
OBJECTIVES The aim of this study was to evaluate vascular function in the lower extremities by making direct time-course measurement of oxygen saturation in the femoral/popliteal arteries and veins during cuff-induced reactive hyperemia with magnetic resonance imaging-based oximetry. BACKGROUND Magnetic resonance imaging-based oximetry is a new calibration-free technique taking advantage of the paramagnetic nature of blood that depends on the volume fraction of deoxyhemoglobin in red blood cells. METHODS We compared post-occlusive blood oxygenation time-course of femoral/popliteal vessels in: 1) young healthy subjects (YH) (n = 10; mean ankle-brachial index [ABI] 1.0 +/- 0.1, mean age 30 +/- 7 years); 2) peripheral arterial disease (PAD) patients (n = 12; mean ABI 0.6 +/- 0.1, mean age 71 +/- 9 years); and 3) age-matched healthy control subjects (AHC) (n = 8; mean ABI 1.1 +/- 0.1, mean age 68 +/- 9 years). Blood oxygenation was quantified at 3.0-T field strength with a field mapping pulse sequence yielding the magnetic susceptibility difference between blood in the vessels and surrounding muscle tissue from which the intravascular blood oxygen saturation is computed as %HbO(2). RESULTS Significantly longer washout time (42 +/- 16 s vs. 14 +/- 4 s; p < 0.0001) and lower upslope (0.60 +/- 0.20 %HbO(2)/s vs. 1.32 +/- 0.41 %HbO(2)/s; p = 0.0008) were observed for PAD patients compared with healthy subjects (YH and AHC combined). Furthermore, greater overshoot was observed in YH than in AHC (21 +/- 8 %HbO(2) vs. 10 +/- 5 %HbO(2); p = 0.0116). CONCLUSIONS Post-occlusive transient changes in venous blood oxygenation might provide a new measure of vascular competence, which was found to be reduced in subjects with abnormal ABI, manifesting in prolonged recovery during the early phase of hyperemia.
Collapse
Affiliation(s)
- Michael C Langham
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | | | | | | | | |
Collapse
|
41
|
Feasibility of cardiac gating free of interference with electro-magnetic fields at 1.5 Tesla, 3.0 Tesla and 7.0 Tesla using an MR-stethoscope. Invest Radiol 2009; 44:539-47. [PMID: 19652614 DOI: 10.1097/rli.0b013e3181b4c15e] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To circumvent the challenges of conventional electrocardiographic (ECG)-gating by examining the efficacy of an MR stethoscope, which offers (i) no risk of high voltage induction or patient burns, (ii) immunity to electromagnetic interference, (iii) suitability for all magnetic field strengths, and (iv) patient comfort together with ease of use for the pursuit of reliable and safe (ultra)high field cardiac gated magnetic resonance imaging (MRI). MATERIALS AND METHODS The acoustic gating device consists of 3 main components: an acoustic sensor, a signal processing unit, and a coupler unit to the MRI system. Signal conditioning and conversion are conducted outside the 0.5 mT line using dedicated electronic circuits. The final waveform is delivered to the internal physiological signal controller circuitry of a clinical MR scanner. Cardiovascular MRI was performed of normal volunteers (n = 17) on 1.5 T, 3.0 T and 7.0 T whole body MR systems. Black blood imaging, 2D CINE imaging, 3D phase contrast MR angiography, and myocardial T2* mapping were carried out. RESULTS The MR-stethoscope provided cardiograms at 1.5 T, 3.0 T and 7.0 T free of interference from electromagnetic fields and magneto-hydrodynamic effects. In comparison, ECG waveforms were susceptible to T-wave elevation and other distortions, which were more pronounced at higher fields. Acoustically gated black blood imaging at 1.5 T and 3.0 T provided image quality comparable with or even superior to that obtained from the ECG-gated approach. In the case of correct R-wave recognition, ECG-gated 2D CINE SSFP imaging was found to be immune to cardiac motion effects -even at 3.0 T. However, ECG-gated 2D SSFP CINE imaging was prone to cardiac motion artifacts if R-wave mis-registration occurred because of T-wave elevation. Acoustically gated 3D PCMRA at 1.5 T, 3.0 T and 7.0 T resulted in images free of blood pulsation artifacts because the acoustic gating approach provided cardiac signal traces free of interference with electromagnetic fields or magneto-hydrodynamic effects even at 7.0 Tesla. Severe ECG-trace distortions and T-wave elevations occurred at 3.0 T and 7.0 T. Acoustically cardiac gated T2* mapping at 3.0 T yielded a T2* value of 22.3 +/- 4.8 ms for the inferoseptal myocardium. CONCLUSIONS The proposed MR-stethoscope presents a promising alternative to currently available techniques for cardiac gating of (ultra)high field MRI. Its intrinsic insensitivity to interference from electromagnetic fields renders it suitable for clinical imaging because of its excellent trigger reliability, even at 7.0 Tesla.
Collapse
|
42
|
Heinrichs U, Utting JF, Frauenrath T, Hezel F, Krombach GA, Hodenius MA, Kozerke S, Niendorf T. MyocardialT2*mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T. Magn Reson Med 2009; 62:822-8. [DOI: 10.1002/mrm.22054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
43
|
|
44
|
Damon BM, Wadington MC, Hornberger JL, Lansdown DA. Absolute and relative contributions of BOLD effects to the muscle functional MRI signal intensity time course: effect of exercise intensity. Magn Reson Med 2007; 58:335-45. [PMID: 17654591 PMCID: PMC4440487 DOI: 10.1002/mrm.21319] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The time course of exercise-induced T(2)-weighted signal intensity (SI) changes contains an initial rise, early dip, and secondary rise. The purposes of this study were to test the hypothesis that the secondary rise occurs earlier during more intense contractions, and to determine the contribution of BOLD contrast to the SI changes. Eight subjects performed 90-s isometric dorsiflexion contractions at 30% and 60% of maximum voluntary contraction (MVC) while T(2)-weighted (TR/TE = 4000 ms/35 ms) images were acquired and total hemoglobin ([THb]) and oxy-Hb saturation (%HbO(2)) were measured. At 30% MVC, [THb] remained constant and %HbO(2) decreased from 66.3% (standard error [SEM] = 2.6%) to 32.4% (SEM = 6.4%). At t = 88 s, SI increased by approximately 8% and was greater than at t = 8 and 56 s. At 60% MVC, [THb] remained constant and %HbO(2) decreased from 70.2% (SEM = 2.3%) to 40.4% (SEM = 5.4%). SI increased by approximately 17% and at t = 56 and 88 s was greater than at t = 8 and 20 s. The absolute contribution of calculated BOLD effects was -1% at 30% and 60% MVC. The relative contribution was greater at 30% than at 60% MVC (up to -26% and -10%, respectively). We conclude that the secondary rise occurs earlier at 60% MVC and that the relative contribution of BOLD effects is greater during less intense contractions.
Collapse
Affiliation(s)
- Bruce M Damon
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232, USA.
| | | | | | | |
Collapse
|
45
|
Schachinger H, Klarhöfer M, Linder L, Drewe J, Scheffler K. Angiotensin II decreases the renal MRI blood oxygenation level-dependent signal. Hypertension 2006; 47:1062-6. [PMID: 16618841 DOI: 10.1161/01.hyp.0000220109.98142.a3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acute experimental reduction of renal blood flow decreases the renal blood oxygenation level-dependent (BOLD) MRI signal in animals. Angiotensin II also reduces renal blood flow, but the ability of BOLD MRI to dynamically detect this response has not yet been investigated in humans. Six healthy male volunteers underwent an individual dose-finding study to identify the intravenous doses of angiotensin II, norepinephrine, and sodium nitroprusside necessary to induce a 15-mm Hg peak mean arterial blood pressure change. MRI studies followed within 3 weeks, when angiotensin II (8.8+/-1.4 ng/kg), norepinephrine (52+/-12 ng/kg), and sodium nitroprusside (2.0+/-0.3 microg/kg) were given twice in an unblocked, randomized sequence while imaging experiments were performed on a 1.5-T Siemens Sonata. A multiecho echo-planar imaging sequence was used to acquire T2* maps with a temporal resolution of 1 respiratory cycle. Averaged over a renal cortex dominated region of interest, angiotensin II caused a shortening of T2* between 6% and 10%. Sodium nitroprusside and norepinephrine, although of equal potency concerning blood pressure responses, did not alter the renal BOLD signal. The renal BOLD response to angiotensin II appeared with short onset latency (as early as 10 seconds after peripheral intravenous angiotensin II bolus administration) suggesting that this response is a consequence of altered perfusion rather than increased renal oxygen consumption. The methods described here are suitable to assess renal responsiveness to angiotensin II and may, thus, be of great value in human hypertension research.
Collapse
Affiliation(s)
- Hartmut Schachinger
- Division of Clinical Physiology, Graduate School of Psychobiology, University of Trier, Trier, Germany.
| | | | | | | | | |
Collapse
|