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Dohra H, Fujishima M, Suzuki H. Analysis of amino acid and codon usage in Paramecium bursaria. FEBS Lett 2015; 589:3113-8. [PMID: 26341535 DOI: 10.1016/j.febslet.2015.08.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 01/28/2023]
Abstract
The ciliate Paramecium bursaria harbors the green-alga Chlorella symbionts. We reassembled the P. bursaria transcriptome to minimize falsely fused transcripts, and investigated amino acid and codon usage using the transcriptome data. Surface proteins preferentially use smaller amino acid residues like cysteine. Unusual synonymous codon and amino acid usage in highly expressed genes can reflect a balance between translational selection and other factors. A correlation of gene expression level with synonymous codon or amino acid usage is emphasized in genes down-regulated in symbiont-bearing cells compared to symbiont-free cells. Our results imply that the selection is associated with P. bursaria-Chlorella symbiosis.
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Affiliation(s)
- Hideo Dohra
- Instrumental Research Support Office, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan; Department of Biological Science, Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Masahiro Fujishima
- Department of Environmental Science and Engineering, Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan; National Bio-Resource Project of Japan Agency for Medical Research and Development, Japan
| | - Haruo Suzuki
- Department of Environmental Science and Engineering, Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan.
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Kirschner R, Pécsvárady Z, Bedros JR, Tóth L, Kiss K, Simor T. [Dobutamine stress cardiovascular magnetic resonance imaging in patients with peripheral artery disease]. Orv Hetil 2011; 152:285-91. [PMID: 21310697 DOI: 10.1556/oh.2011.29040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Patients with peripheral arterial disease often have coronary heart disease, as well. However, their assessment with classical noninvasive cardiology methods is often non-diagnostic or limited. The aim of this study was to analyze the feasibility and the risks of dobutamine stress cardiovascular MRI for cardiac evaluation of patients with peripheral arterial disease. 21 patients with peripheral artery disease (mean±SD age 64.3±7.7 years) were studied prospectively with dobutamine stress cardiovascular MRI. The protocol was completed by all of 21 patients. The target heart rate was attained in 95.2% of the studies. No serious adverse event occurred. The image quality scores (1-4) for all ventricular wall segments were high (median, interquartile range) (4 [4-4]). Five patients (23.8%) have inducible wall motion abnormality. Interobserver agreement was almost perfect for wall motion scores (κ = 0.87, p<0.0001). Dobutamine stress cardiovascular MRI is feasible with low risk for the cardiological assessment of patients with peripheral arterial disease.
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Affiliation(s)
- Róbert Kirschner
- Pest Megyei Flór Ferenc Kórház III. Belgyógyászat, Kardiológia Osztály Kistarcsa Semmelweis tér 1. 2143 Pécsi Tudományegyetem, Általános Orvostudományi Kar Szívgyógyászati Klinika Pécs.
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Hundley WG, Bluemke DA, Finn JP, Flamm SD, Fogel MA, Friedrich MG, Ho VB, Jerosch-Herold M, Kramer CM, Manning WJ, Patel M, Pohost GM, Stillman AE, White RD, Woodard PK. ACCF/ACR/AHA/NASCI/SCMR 2010 expert consensus document on cardiovascular magnetic resonance: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. J Am Coll Cardiol 2010; 55:2614-62. [PMID: 20513610 PMCID: PMC3042771 DOI: 10.1016/j.jacc.2009.11.011] [Citation(s) in RCA: 450] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Hundley WG, Bluemke DA, Finn JP, Flamm SD, Fogel MA, Friedrich MG, Ho VB, Jerosch-Herold M, Kramer CM, Manning WJ, Patel M, Pohost GM, Stillman AE, White RD, Woodard PK. ACCF/ACR/AHA/NASCI/SCMR 2010 expert consensus document on cardiovascular magnetic resonance: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. Circulation 2010; 121:2462-508. [PMID: 20479157 PMCID: PMC3034132 DOI: 10.1161/cir.0b013e3181d44a8f] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Husser O, Bodí V, Sanchís J, Mainar L, Núñez J, López-Lereu MP, Monmeneu JV, Ruiz V, Rumiz E, Moratal D, Chorro FJ, Llácer A. Additional diagnostic value of systolic dysfunction induced by dipyridamole stress cardiac magnetic resonance used in detecting coronary artery disease. Rev Esp Cardiol 2009; 62:383-91. [PMID: 19401123 DOI: 10.1016/s1885-5857(09)71665-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION AND OBJECTIVES Dipyridamole stress perfusion cardiovascular magnetic resonance (CMR) is used to detect coronary artery disease (CAD). However, few data are available on the diagnostic value of the systolic dysfunction induced by dipyridamole. This study investigated whether the induction of systolic dysfunction supplements the diagnostic information provided by perfusion imaging in the detection of CAD. METHODS Overall, 166 patients underwent dipyridamole CMR and quantitative coronary angiography, with CAD being defined as a stenosis > or =70%. Systolic dysfunction at rest, systolic dysfunction with dipyridamole, induced systolic dysfunction, and stress first-pass perfussion deficit (PD) and delayed enhancement were quantified. RESULTS In the multivariate analysis, PD (hazard ratio [HR]=1.6; 95% confidence interval [CI], 1.33-1.91;P< .0001) and induced systolic dysfunction (OR=1.8; 95% CI, 1.18-2.28; P< .007) were independently associated with CAD and had a sensitivity and specificity of 92% and 62% and 43% and 96%, respectively. Patients were categorized as having no ischemia (Group 1), PD but no induced systolic dysfunction (Group 2), or induced systolic dysfunction irrespective of PD (Group 3). In Group 3, the prevalence of CAD was higher than in Group 1 or 2 (96% vs. 22% and 79%, respectively; P=.001) and the risk of CAD was two-fold higher than in Group 2 (OR=2.34; 95% CI, 1.07-5.13; P=.034). Compared with Group 2, more hypoperfused segments were observed in Group 3 (6.2+/-2.6 vs. 7.4+/-3.4; P=.044), and more diseased vessels (1.4+/-1.0 vs. 1.8+/-0.9; P=.036). Adding induced systolic dysfunction to perfusion and clinical data improved the multivariate model's C-statistic for predicting CAD (0.81 vs. 0.87; P=.02). CONCLUSIONS Combining induced systolic dysfunction with perfusion imaging increases the diagnostic accuracy of detecting CAD and enables patients with severe ischemia and a high probability of CAD to be identified.
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Affiliation(s)
- Oliver Husser
- Servicio de Cardiología, Hospital Clínico Universitario, Universitat de València, Valencia 46010, Spain
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Valor diagnóstico adicional de la disfunción sistólica inducida para la detección de enfermedad coronaria mediante resonancia magnética cardiaca de estrés con dipiridamol. Rev Esp Cardiol 2009. [DOI: 10.1016/s0300-8932(09)70895-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Nandalur KR, Dwamena BA, Choudhri AF, Nandalur MR, Carlos RC. Diagnostic performance of stress cardiac magnetic resonance imaging in the detection of coronary artery disease: a meta-analysis. J Am Coll Cardiol 2007; 50:1343-53. [PMID: 17903634 DOI: 10.1016/j.jacc.2007.06.030] [Citation(s) in RCA: 369] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 05/09/2007] [Accepted: 06/25/2007] [Indexed: 12/30/2022]
Abstract
OBJECTIVES The purpose of our study was to conduct an evidence-based evaluation of stress cardiac magnetic resonance imaging (MRI) in the diagnosis of coronary artery disease (CAD). BACKGROUND Stress cardiac MRI has recently emerged as a noninvasive method in the detection of CAD, with 2 main techniques in use: 1) perfusion imaging; and 2) stress-induced wall motion abnormalities imaging. METHODS We examined studies from January 1990 to January 2007 using MEDLINE and EMBASE. A study was included if it: 1) used stress MRI as a diagnostic test for CAD (> or =50% diameter stenosis); and 2) used catheter X-ray angiography as the reference standard. RESULTS Thirty-seven studies (2,191 patients) met the inclusion criteria, with 14 datasets (754 patients) using stress-induced wall motion abnormalities imaging and 24 datasets (1,516 patients) using perfusion imaging. Stress-induced wall motion abnormalities imaging demonstrated a sensitivity of 0.83 (95% confidence interval [CI] 0.79 to 0.88) and specificity of 0.86 (95% CI 0.81 to 0.91) on a patient level (disease prevalence = 70.5%). Perfusion imaging demonstrated a sensitivity of 0.91 (95% CI 0.88 to 0.94) and specificity of 0.81 (95% CI 0.77 to 0.85) on a patient level (disease prevalence = 57.4%). CONCLUSIONS In studies with high disease prevalence, stress cardiac MRI, using either technique, demonstrates overall good sensitivity and specificity for the diagnosis of CAD. However, limited data are available regarding use of either technique in populations with low disease prevalence.
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Affiliation(s)
- Kiran R Nandalur
- Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
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Strach K, Meyer C, Schild H, Sommer T. Cardiac stress MR imaging with dobutamine. Eur Radiol 2006; 16:2728-38. [PMID: 16715237 DOI: 10.1007/s00330-006-0295-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2005] [Revised: 03/14/2006] [Accepted: 03/28/2006] [Indexed: 10/24/2022]
Abstract
Stress testing for detection of ischemia-induced wall-motion abnormalities has become a mainstay for noninvasive diagnosis and risk stratification of patients with suspected coronary artery disease (CAD). Recent technical developments in magnetic resonance imaging (MRI), including the adoption of balanced steady-state free precession (b-SSFP) sequences-preferentially in combination with parallel imaging techniques-have led to a significant reduction of imaging time and improved patient safety. The stress protocol includes application of high-dose dobutamine (up to 40 microg/kg/min) combined with fractionated atropine (up to a maximal dose of 1.0 mg). High-dose dobutamine stress MRI revealed good sensitivity (83-96%) and specificity (80-100%) for detection of significant CAD. Myocardial tagging methods have been shown to further increase sensitivity for CAD detection. Severe complications (sustained tachycardia, ventricular fibrillation, myocardial infarction, cardiogenic shock) are rare but may be expected in 0.1-0.3% of patients. Dobutamine stress MRI has emerged as a reliable and safe clinical alternative for noninvasive assessment of CAD. New pulse sequences, such as real-time imaging, might obviate the need for breath holding and electrocardiogram (ECG) triggering in patients with severe dyspnoea and cardiac arrhythmias, which may further improve the clinical impact and acceptance of stress MRI in the future.
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Affiliation(s)
- K Strach
- Department of Radiology, University of Bonn, Sigmund-Freud Str. 25, 53105, Bonn, Germany
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11
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Abstract
Magnetic resonance imaging and/or contrast-enhanced multidetector computed tomography may be used separately or, often more effectively, in an integrated fashion, to address important issues in patients with coronary artery disease causing ischemic cardiac disease (ICD). These issues include complications of myocardial infarction, such as ventricular dysfunction, myocardial wall rupture, aneurysm formation, intracavitary thrombus, mitral insufficiency, and pericarditis, as well as aspects of planning and monitoring therapy for ICD, such as revascularization and ventricular aneurysm repair.
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Affiliation(s)
- Richard D White
- Center for Integrated Non-Invasive Cardiovascular Imaging, Department of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
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Pujadas S, Reddy GP, Weber O, Lee JJ, Higgins CB. MR imaging assessment of cardiac function. J Magn Reson Imaging 2004; 19:789-99. [PMID: 15170784 DOI: 10.1002/jmri.20079] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Magnetic resonance (MR) imaging is an accurate and reproducible technique for assessment of ventricular function. Although echocardiography is the mainstay for evaluation of cardiac function, dobutamine stress MR imaging has been shown to be as safe as echocardiography for patients with coronary artery disease and more accurate in patients with suboptimal echocardiographic image quality. This article reviews MR imaging techniques, methods of pharmacologic stress, and clinical applications for assessment of cardiac function, primarily left ventricular function.
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Affiliation(s)
- Sandra Pujadas
- Department of Radiology, University of California, San Francisco, California 94143-0628, USA
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Pujadas S, Reddy GP, Lee JJ, Higgins CB. Magnetic resonance imaging in ischemic heart disease. Semin Roentgenol 2003; 38:320-9. [PMID: 14621374 DOI: 10.1016/s0037-198x(03)00054-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Sandra Pujadas
- Department of Radiology, Suite M396, 505 Parnassus Avenue, Box 0628, University of California, San Francisco, San Francisco, CA 94143-0628, USA
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Pohost GM, Biederman RW, Doyle M. Cardiovascular magnetic resonance imaging and spectroscopy in the new millennium. Curr Probl Cardiol 2000; 25:525-620. [PMID: 10964282 DOI: 10.1067/mcd.2000.108428] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- G M Pohost
- University of Alabama at Birmingham, Birmingham, AL, USA
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16
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van der Wall EE, Bax J. Current clinical relevance of cardiovascular magnetic resonance and its relationship to nuclear cardiology. J Nucl Cardiol 1999; 6:462-9. [PMID: 10461614 DOI: 10.1016/s1071-3581(99)90013-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Kaemmerer H, Ibrahim T, Schwaiger M, Hess J. [Magnetic resonance imaging and spiral computed tomography in the diagnosis and follow-up of adults with congenital heart and vessel disease]. Herz 1999; 24:263-75. [PMID: 10444706 DOI: 10.1007/bf03043878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Management of patients with congenital heart disease requires detailed information on cardiac and great vessel morphology. In previous years the diagnosis and treatment of congenital malformations often depended on cardiac catheterization and in many institutions cardiac catheterization still remains the gold standard against which other modalities are measured. In the past decade, however, imaging methodologies have increasingly shifted toward the use of less invasive and noninvasive techniques. Currently, echocardiography is the initial method of choice in evaluating the anatomy, especially in younger patients. Meanwhile, several newer imaging techniques like magnetic resonance imaging (MRI) and computed tomography (CT) are in use. They offer extremely useful information about abnormalities of the heart and great vessels as well as for the assessment of cardiac anatomy and function. Echo, angiography, MRT and CT should be seen as complementary investigations in adult congenital heart disease.
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Affiliation(s)
- H Kaemmerer
- Klinik für Kinderkardiologie und angeborene Herzfehler im Deutschen Herzzentrum München.
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Schwitter J, Saeed M, Wendland MF, Sakuma H, Bremerich J, Canet E, Higgins CB. Assessment of myocardial function and perfusion in a canine model of non-occlusive coronary artery stenosis using fast magnetic resonance imaging. J Magn Reson Imaging 1999; 9:101-10. [PMID: 10030657 DOI: 10.1002/(sici)1522-2586(199901)9:1<101::aid-jmri14>3.0.co;2-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Magnetic resonance (MR) functional and perfusion imaging were employed in a canine model of coronary artery stenosis (n = 6) for the quantification of functional and perfusion deficits before and after dipyridamole administration. Left anterior descending and circumflex (LCX) coronary blood flow were measured continuously after placing Doppler flowmeters. Inversion recovery gradient echo images during the transit of MR contrast medium gadolinium-benzyloxypropionictetraacetate dimeglumine (Gd-BOPTA/Dimeg) and fast breath-hold cine MR images were acquired at baseline, during LCX stenosis in basal state, and during LCX stenosis with vasodilation (dipyridamole 0.5 mg/kg). The extent of the functional defect and perfusion defect was expressed as percent of left ventricle (LV) circumference. During stenosis (LCX flow: 62.6 +/- 5.6% of baseline) the extent of the functional defect was slightly larger than the perfusion defect (11.0 +/- 1.8% versus 6.3 +/- 1.70% of LV circumference, respectively; P < 0.01). During vasodilation the extent of the functional defect was considerably smaller than the perfusion defect (25.3 +/- 2.5% versus 35.3 +/- 3.5%; P < 0.01). Thus, the sizes of ischemic regions displayed by MR perfusion defect and functional defect differ from each other.
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Affiliation(s)
- J Schwitter
- Department of Radiology, University of California San Francisco, 94143-0628, USA
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Pennell DJ, Manzara CC, Underwood SR, Longmore DB. Optimization of magnetic resonance imaging parameters for left ventricular wall motion studies at 0.5 T. Br J Radiol 1998; 71:1033-9. [PMID: 10211063 DOI: 10.1259/bjr.71.850.10211063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Magnetic resonance cine imaging of left ventricular wall motion at rest or during stress may be used to assess myocardial function, infarction and viability, or reversible ischaemia. Whilst interpretation of the cines rests critically on image quality, there is little in the literature which systematically examines the optimal imaging parameters for such wall motion studies at rest or during stress. This study was designed to examine several imaging parameters for cine optimization using a conventional 0.5 T scanner. Gradient echo imaging was performed in two groups of volunteers with varying echo times and flip angles. The period between excitations was 80 ms (simulating a resting heart rate) in one group, and 40 ms (simulating tachycardia during stress) in the other group. Short axis imaging yielded the highest contrast between blood and myocardium for both repetition times (rest p = 0.02; stress p < 0.001) compared with the long axes, because of magnetic saturation of blood moving slowly in-plane. Contrast was higher at end-diastole than end-systole for the long axes (rest p < 0.0001; stress p < 0.0002), but not significantly different in the short axis. Increasing the echo time and flip angle resulted in increased signal but eventually caused motion artefact and magnetic saturation of blood. The optimal parameters were an echo time of 14 ms and a 45 degrees flip angle for resting heart rates, with the flip angle falling to between 35 degrees and 45 degrees for tachycardia. The choice of imaging parameters is therefore a compromise between improved signal and unwanted artefacts, although the latter are less evident in the short axis plane, which yields the best contrast results because of high blood inflow effects.
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Affiliation(s)
- D J Pennell
- Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
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21
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Zhao S, Croisille P, Janier M, Roux JP, Plana A, Magnin I, Revel D. Comparison between qualitative and quantitative wall motion analyses using dipyridamole stress breath-hold cine magnetic resonance imaging in patients with severe coronary artery stenosis. Magn Reson Imaging 1997; 15:891-8. [PMID: 9322208 DOI: 10.1016/s0730-725x(97)00005-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Breath-hold cine magnetic resonance imaging (MRI) at rest and during dipyridamole infusion was used to study wall motion abnormalities in patients with severe coronary artery stenosis proven by coronary angiography. Sixteen patients without myocardial infarction but at least one major coronary artery with > or = 70% diameter narrowing were included. Qualitative "visual" assessment of wall motion, as well as quantitative measurement "wall thickening changes (%)" were compared using receiver operating characteristic curve analysis. 201Tl-single-photon emission computed tomography (SPECT) was also studied for comparison. Using qualitative analysis, coronary artery disease detection rate was comparable when assessing wall motion abnormalities with dipyridamole-MRI (79%) and with dipyridamole-induced perfusion defects with 201-thallium-SPECT (75%). Furthermore, sensitivity and specificity for identification of all diseased coronary territories were comparable for both imaging modalities (sensitivity of dipyridamole-MRI and 201thallium-SPECT, 80% vs. 69%; specificity, 75% vs. 80%). The quantitative method has a substantially higher sensitivity than the qualitative method in identifying all diseased territories (Az = 0.81, p < 0.01 vs. Az = 0.55 and 0.59). In addition, we demonstrated that the quantitative method had higher performance than the qualitative one in identifying the diseased vessels territories related to 1-vessel, 2-vessel, and each of individual coronary artery stenoses.
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Affiliation(s)
- S Zhao
- Laboratoire Creatis-UMR CNRS 5515, Hôpital Cardiovasculaire et Pneumologique Lyon, France
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22
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Dendale P, Franken PR, Meusel M, van der Geest R, de Roos A. Distinction between open and occluded infarct-related arteries using contrast-enhanced magnetic resonance imaging. Am J Cardiol 1997; 80:334-6. [PMID: 9264428 DOI: 10.1016/s0002-9149(97)00355-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ultrafast contrast-enhanced magnetic resonance imaging can be used to distinguish open and closed infarct-related arteries. An open artery is characterized by a faster rise and fall in signal intensity.
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Affiliation(s)
- P Dendale
- Department of Cardiology, Academic Hospital, Vrije Universiteit Brussel, Belgium
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23
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Holman ER, Buller VG, de Roos A, van der Geest RJ, Baur LH, van der Laarse A, Bruschke AV, Reiber JH, van der Wall EE. Detection and quantification of dysfunctional myocardium by magnetic resonance imaging. A new three-dimensional method for quantitative wall-thickening analysis. Circulation 1997; 95:924-31. [PMID: 9054752 DOI: 10.1161/01.cir.95.4.924] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Regional left ventricular dysfunction is a major consequence of myocardial ischemia, and its extent determines long-term prognosis. Accurate and reproducible analysis of left ventricular dysfunction is therefore useful for risk stratification and patient management. METHODS AND RESULTS Short-axis cardiac cine magnetic resonance (MR) imaging was performed in 25 patients after anterior myocardial infarction at 21 +/- 2.1 days after the acute onset. The MR images were analyzed with the use of a dedicated analytical software package (MASS version 1.0), which includes a modified centerline method and a new three-dimensional analysis approach. A database of 48 healthy volunteers was constructed to objectively depict myocardial dysfunction in the patients; this database was compared with enzymatically determined infarct size. The mean (+/-SEM) quantity of dysfunctional myocardium and enzymatically calculated infarct size equaled 24.0 +/- 3.0 and 22.3 +/- 2.9 g, respectively (P = .69). Enzymatically determined infarct size correlated strongly with left ventricular dysfunction determined by cine MR imaging (y = 0.90x + .92. P < .0001). Segments related to the distribution of the left anterior descending coronary artery showed a significantly lower percentage wall thickening in patients than did corresponding segments of 48 normal subjects (46.0 +/- 8.22% versus 87.1 +/- mean SEM, respectively; P < .001). The mean (+/-SEM) end diastolic wall thickness of the infarcted segment did not differ from that of corresponding normal segments (7.4 +/- 0.33 versus 7.5 +/- 0.15 mm; P = .75). CONCLUSIONS We conclude that the use of three-dimensional quantitative analysis of cine MR images accurately quantities the extent of regional left ventricular dysfunction in the infarcted heart. This method of analysis may be useful in assessing the effect of interventional therapies.
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Affiliation(s)
- E R Holman
- Department of Cardiology, University Hospital, Leiden, Netherlands
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Saeed M, Wendland MF, Szolar D, Sakuma H, Geschwind JF, Globits S, Derugin N, Higgins CB. Quantification of the extent of area at risk with fast contrast-enhanced magnetic resonance imaging in experimental coronary artery stenosis. Am Heart J 1996; 132:921-32. [PMID: 8892762 DOI: 10.1016/s0002-8703(96)90000-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Fast magnetic resonance (MR) imaging techniques have the capability of demonstrating regions of ischemia caused by stenosis. The size of the potentially ischemic area determines the importance of the stenosis. The purpose of this study was to determine the relative values of relaxivity-enhancing and magnetic-susceptibility MR contrast media in detecting and sizing the area at risk in dogs. Eight dogs were subjected to critical left circumflex coronary artery (LCX) stenosis. Sixty sequential inversion-recovery- and driven-equilibrium-prepared fast gradient recalled echo images were acquired during bolus administration of 0.03 mmol/kg gadodiamide or 0.4 mmol/kg sprodiamide in basal and vasodilated (dipyridamole-stress) states. The size of the area at risk was measured and compared with that measured post mortem. In the basal state, gadodiamide and sprodiamide equivalently altered the signal intensities of nonischemic myocardium and the territory of stenosed coronary artery. Dipyridamole produced a significant increase in left anterior descending coronary artery flow with a decrease in LCX flow. The hypoperfused region was observed as a low-and high-signal intensity region after administration of gadodiamide and sprodiamide, respectively. The size of the hypoperfused region was slightly smaller with gadodiamide (37.4% +/- 2.8%) and sprodiamide (34.0% +/- 2.2%) than the true area at risk measured post mortem (41.8% +/- 2.2%; p < 0.05). Dipyridamole perfusion MR imaging with relaxivity or susceptibility contrast media is a noninvasive method to identify and quantify the area at risk in the territory of a stenotic coronary artery. Changes in myocardial signal intensity on fast gradient recalled echo images reflect the augmentation of flow and volume induced with dipyridamole and are consistent with the "steal phenomenon."
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Affiliation(s)
- M Saeed
- Department of Radiology, University of California, San Francisco 94143, USA
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Abstract
The clinical use of MR imaging in ischemic heart disease is still limited, although this is the major cardiac disease afflicting populations of many countries. However, with the recent development of faster MR techniques, MR imaging provides multiple capabilities for the evaluation of most aspects of ischemic heart disease. We described the potential application of MR imaging for identifying and quantifying morphologic and functional alterations caused by myocardial infarction and ischemia; the contribution of MR contrast media to improve tissue characterization and to identify ischemic myocardium; and the application of fast MR imaging techniques for assessing anatomy and blood flow in the native coronary arteries and bypass conduits. With continued development of these capabilities, MR imaging has the potential to be a comprehensive noninvasive imaging modality in ischemic heart disease.
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Affiliation(s)
- J C Steffans
- Department of Radiology, University of California, San Francisco, 94143-0628, USA
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Hofman MB, de Cock CC, van der Linden JC, van Rossum AC, Visser FC, Sprenger M, Westerhof N. Transesophageal cardiac pacing during magnetic resonance imaging: feasibility and safety considerations. Magn Reson Med 1996; 35:413-22. [PMID: 8699954 DOI: 10.1002/mrm.1910350320] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The feasibility and safety of transesophageal cardiac pacing during clinical MRI at 1.5 Tesla is considered. An MRI compatible pace catheter was developed. In vitro testing showed a normal performance of the pulse generator, image artifacts that extended less than 11 mm from the catheter, and a less than 5% increase in noise. Cardiac stimulation induced by MRI was not observed and, theoretically, is not expected. Potentially, tissue around the catheter tip may become heated. This heating (delta tau) was monitored. Eight dogs were exposed to MRI during pacing. For low RF radiation exposure, a time-averaged squared B1 field below 0.08 p tau 2 (SAR < 0.03 W/kg), delta tau was below 1 degree C. For high RF radiation exposure, but at normal RF radiation specific absorption rate (0.4 W/kg) delta tau was 5 degrees C. Thus, transesophageal atrial pacing during MRI at low RF exposure seems to be possible to perform cardiac stress studies or to correct unstable heart rates.
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Affiliation(s)
- M B Hofman
- Department of Clinical Physics and Engineering, ICaR-VU, Free University, Amsterdam, The Netherlands
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Severi S, Underwood R, Mohiaddin RH, Boyd H, Paterni M, Camici PG. Dobutamine stress: effects on regional myocardial blood flow and wall motion. J Am Coll Cardiol 1995; 26:1187-95. [PMID: 7594031 DOI: 10.1016/0735-1097(95)00319-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES This investigation studied the relation between regional myocardial blood flow and left ventricular function during dobutamine stress in patients with coronary artery disease. BACKGROUND Dobutamine stress is becoming more frequently used as an alternative to dynamic exercise in patients with ischemic heart disease. METHODS We studied 12 patients with coronary artery disease. Dobutamine was infused from 5 micrograms/kg body weight per min up to 40 micrograms/kg per min or until chest pain or other intolerable side effects. Regional myocardial blood flow was measured with positron emission tomography and oxygen-15-labeled water. Regional wall motion was assessed in three short-axis slices by magnetic resonance imaging. Each slice was subdivided into four regions: septal, anterior, lateral and inferior. A total of 140 regions were suitable for comparison. RESULTS During stress, new wall motion abnormalities developed in 27 regions. Myocardial blood flow (mean +/- SD) increased in 113 regions that did not develop wall motion abnormalities (0.98 +/- 0.26 [baseline] vs. 1.98 +/- 0.87 [dobutamine] ml/min per g, p < 0.001), whereas it did not change significantly in regions with stress-induced wall motion abnormalities (1.00 +/- 0.28 [baseline] vs. 1.30 +/- 0.62 [dobutamine] ml/min per g, p = NS). An absolute decrease in myocardial blood flow below the value at rest was observed in seven segments that developed wall motion abnormalities during stress. CONCLUSIONS The normal functional response to dobutamine stress is paralleled by an increase in coronary flow, whereas mechanical dysfunction is accompanied by a blunted increase, or even a paradoxic decrease, in regional coronary flow.
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Affiliation(s)
- S Severi
- CNR Institute of Clinical Physiology, University of Pisa, Italy
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Holman ER, Vliegen HW, van der Geest RJ, Reiber JH, van Dijkman PR, van der Laarse A, de Roos A, van der Wall EE. Quantitative analysis of regional left ventricular function after myocardial infarction in the pig assessed with cine magnetic resonance imaging. Magn Reson Med 1995; 34:161-9. [PMID: 7476074 DOI: 10.1002/mrm.1910340206] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
To assess the accuracy of quantitative analysis of global and regional wall motion and wall thickening of the left ventricle with cine magnetic resonance (MR), images obtained in eight pigs before and after myocardial infarction were compared with those obtained using gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced multislice spin-echo MR imaging and determination of pathology. The region with abnormal wall motion and wall thickening, as determined with cine MR imaging, identified the same region of infarction as indicated by Gd-DTPA-enhanced spin-echo MR imaging and pathology. Within the infarcted region wall motion and wall thickening analyzed with the centerline method were significantly reduced. We conclude that the use of quantitative analysis of cine MR images accurately determines localization and extent of regional left ventricular dysfunction in the infarcted heart in vivo. This analysis using dedicated software including the centerline method allows sequential assessment of regional left ventricular function in normal and infarcted hearts.
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Affiliation(s)
- E R Holman
- Department of Cardiology, University Hospital, Leiden, The Netherlands
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Cohen MC, McKenna C, Lewis SM, Muller JE. Requirements for controlled clinical trials of preoperative cardiovascular risk reduction. CONTROLLED CLINICAL TRIALS 1995; 16:89-95. [PMID: 7789138 DOI: 10.1016/0197-2456(94)00068-e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Although controlled clinical trials have had a major impact in many areas of cardiovascular disease management, they have had little influence on preoperative cardiac risk reduction. Over the past 2 years, we have conducted the Reduction of Cardiac Operative Risk (RCOR) Trial, a pilot study designed to determine enrollment and event rates for a definitive trial evaluating a strategy to reduce cardiac risk associated with noncardiac surgery. This experience indicates that a successful, definitive trial will require recognition of the multiple questions to be answered, accurate identification of the study population, a large sample size, cooperation between internists, surgeons, and anesthesiologists, and strategies to minimize cost. The high costs and difficulties of such a trial are likely to be outweighed by the enormous benefit of identifying the proper strategy for the use of the expensive testing methods that are currently employed.
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Affiliation(s)
- M C Cohen
- Cardiovascular Division, Deaconess Hospital, Boston, Massachusetts 02215, USA
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Baer FM, Voth E, Deutsch HJ, Schneider CA, Schicha H, Sechtem U. Assessment of viable myocardium by dobutamine transesophageal echocardiography and comparison with fluorine-18 fluorodeoxyglucose positron emission tomography. J Am Coll Cardiol 1994; 24:343-53. [PMID: 8034866 DOI: 10.1016/0735-1097(94)90286-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The aim of this study was to assess whether dobutamine transesophageal echocardiography can identify viable myocardium in patients with chronic myocardial infarction. BACKGROUND Experimental and clinical studies have shown that dobutamine can recruit a contraction reserve in postischemic viable but akinetic segments, indicating that dobutamine-induced functional recovery is a potential ultrasound marker of myocardial viability. METHODS Forty patients underwent rest and dobutamine transesophageal echocardiography (dobutamine 5, 10 and 20 micrograms/kg body weight per min) and fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography at rest. Three representative short-axis tomograms and a transverse four-chamber-view were used for wall motion and F-18 fluorodeoxyglucose-uptake analysis in corresponding myocardial regions. A basally asynergic segment was considered viable by transesophageal echocardiography if dobutamine-induced systolic wall motion could be observed. Viability by positron emission tomography was defined as F-18 fluorodeoxyglucose uptake > or = 50% of the maximal uptake in a region with normal wall motion by left ventriculography. RESULTS Functional recovery within the infarct region was found in 21 (53%) of 40 patients during dobutamine infusion. Infarct region-related viability by F-18 fluorodeoxyglucose uptake was diagnosed in 25 (63%) of 40 patients, yielding a diagnostic agreement between both techniques in 90% of patients. In 210 (89%) of 235 akinetic segments at rest, data on myocardial viability were concordant by the two techniques. The positive and negative predictive accuracy of dobutamine transesophageal echocardiography for viability defined by F-18 fluorodeoxyglucose uptake was 81% and 97%, respectively. Such uptake was significantly different (p < 0.001) between segments remaining akinetic (mean +/- SD 45 +/- 9%) during dobutamine infusion and segments with a dobutamine-induced contraction reserve (68 +/- 11%). CONCLUSIONS Dobutamine transesophageal echocardiography provides a promising low cost and widely available approach to unmask myocardial viability in patients with chronic myocardial infarction, and results compare favorably with those of F-18 fluorodeoxyglucose positron emission tomography.
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Affiliation(s)
- F M Baer
- Klinik III für Innere Medizin, Universität zu Köln, Germany
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Severi S, Picano E, Michelassi C, Lattanzi F, Landi P, Distante A, L'Abbate A. Diagnostic and prognostic value of dipyridamole echocardiography in patients with suspected coronary artery disease. Comparison with exercise electrocardiography. Circulation 1994; 89:1160-73. [PMID: 8124803 DOI: 10.1161/01.cir.89.3.1160] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Before any new diagnostic test is accepted in clinical practice, such a test should be compared with established diagnostic tools in an appropriately large series of patients encompassing the complete spectrum of challenges to which the test is exposed. The aim of the present study was to assess the relative diagnostic and prognostic accuracies of high-dose dipyridamole echocardiography (two-dimensional echocardiographic monitoring during dipyridamole infusion up to 0.84 mg/kg over 10 hours) versus maximal symptom-limited bicycle exercise ECG test in patients with angina. METHODS AND RESULTS We studied 429 consecutive in-hospital patients who met the following inclusion criteria: history of chest pain, off antianginal therapy for at least 2 days (1 week for beta-blockers), no previous myocardial infarction and/or obvious regional left ventricular dyssynergy of contraction (akinesis or dyskinesis) at baseline, and acceptable acoustic window under resting conditions. All patients underwent dipyridamole echocardiography and exercise ECG--on different days and in random order--within 1 week of coronary angiography (which was performed independent of test results) and were followed up for 37.8 +/- 14 months (range, 1 to 73 months). Criteria of positivity were for dipyridamole echocardiography, a transient regional dyssynergy absent in the baseline examination; for exercise ECG, an ST-segment shift of > or = 0.1 mV from baseline; and for coronary angiography, a luminal reduction of > or = 75% in at least one major coronary vessel (50% for left main). There were 183 patients without and 246 with coronary artery disease; 132 had one-, 70 had two-, and 44 had three- and/or left main vessel disease. The specificity was higher for dipyridamole echocardiography than for exercise ECG (90% versus 51%, P < .001). The overall sensitivity of dipyridamole echocardiography was similar to that of exercise ECG (75% versus 74%, P = NS), with no significant differences in the subset with one- (67% versus 69%, P = NS), two- (79% versus 77%, P = NS), or three- (93% versus 86%, P = NS) vessel disease. During the follow-up, there were 20 deaths, 13 nonfatal myocardial infarctions, and 126 revascularization procedures. In the univariate analysis, dipyridamole resulted in higher chi 2 values than did exercise stress testing. A Cox forward stepwise survival analysis identified the dipyridamole time as the most powerful prognostic predictor of death (chi 2 = 19.4, P < .0001) of all invasive and noninvasive parameters. The dipyridamole time also provided independent and additional prognostic information when it was adjusted for age, diabetes, resting ECG, and exercise stress test according to a modified, interactive stepwise procedure. This is true when death only, death and myocardial infarction, and death, myocardial infarction, and revascularization procedures were considered end points. CONCLUSIONS In patients with no previous myocardial infarction and good resting left ventricular function, compared with exercise ECG, dipyridamole echocardiography has a similar sensitivity and a higher specificity for the noninvasive detection of angiographically assessed coronary artery disease. Dipyridamole echocardiography also provides information in addition to that provided by exercise ECG for predicting death, infarction, and all events when the presence as well as the timing, severity, and extension of dipyridamole-induced wall motion abnormalities are considered.
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Affiliation(s)
- S Severi
- CNR-Institute of Clinical Physiology, Pisa, Italy
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van Rugge FP, van der Wall EE, de Roos A, Bruschke AV. Dobutamine stress magnetic resonance imaging for detection of coronary artery disease. J Am Coll Cardiol 1993; 22:431-9. [PMID: 8335812 DOI: 10.1016/0735-1097(93)90047-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES The clinical value of cine magnetic resonance imaging (MRI) during dobutamine stress for detection of coronary artery disease was evaluated in 45 patients with chest pain who were admitted for coronary arteriography. BACKGROUND Development of stress-induced wall motion asynergy is considered an early and reliable sign of myocardial ischemia preceding electrocardiographic (ECG) changes and angina. As physical exercise during MRI is difficult because of motion artifacts and space restriction, dobutamine infusion was used to induce cardiovascular stress. METHODS Cine MRI tomograms were obtained in six adjacent short-axis planes. After baseline acquisition, dobutamine was administered to a maximal dose of 20 micrograms/kg per min. Both at rest and during peak dobutamine stress, magnetic resonance images were displayed in a cinematographic loop to assess regional wall motion qualitatively. Results of dobutamine MRI were considered positive for coronary artery disease if any new or worsening wall motion abnormality developed. Immediately after MRI at peak dobutamine infusion, dobutamine electrocardiography was performed outside the magnetic environment. In addition, all patients performed symptom-limited exercise electrocardiography. RESULTS Significant coronary artery disease (> 50% diameter stenosis) was present in 37 patients. During peak dobutamine stress, wall motion asynergy developed or worsened in 30 patients, yielding an overall sensitivity for detection of coronary artery disease of 81% and a specificity of 100%. Corresponding data were 51% and 63% for dobutamine electrocardiography and 70% and 63% for exercise electrocardiography. The sensitivity of dobutamine MRI for the detection of coronary artery disease in patients with single-, double- and triple-vessel disease was 75% (15 of 20 patients), 80% (8 of 10) and 100% (7 of 7), respectively. CONCLUSION Dobutamine MRI is an accurate nonexercise-dependent method for the assessment of myocardial ischemia in patients with coronary artery disease.
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Affiliation(s)
- F P van Rugge
- Department of Cardiology, University Hospital Leiden, The Netherlands
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Baer FM, Smolarz K, Theissen P, Voth E, Schicha H, Sechtem U. Identification of hemodynamically significant coronary artery stenoses by dipyridamole-magnetic resonance imaging and 99mTc-methoxyisobutyl-isonitrile-SPECT. INTERNATIONAL JOURNAL OF CARDIAC IMAGING 1993; 9:133-45. [PMID: 8331305 DOI: 10.1007/bf01151437] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Magnetic resonance imaging (MRI) has been used in conjunction with dipyridamole induced wall motion abnormalities for the noninvasive detection of coronary artery disease (CAD). To assess the clinical usefulness of dipyridamole-MRI for the localization of CAD and to evaluate the relation between dipyridamole induced wall motion abnormalities and myocardial perfusion 33 patients with severe CAD (> 70% diameter reduction) underwent MRI at rest and after dipyridamole infusion (0.75 mg dipyridamole/kg over a period of 10 minutes). All patients performed exercise stress testing and 20 patients of the study group additionally had rest and exercise stress 99mTc-methoxyisobutyl-isonitrile-SPECT (MIBI-SPECT). Two patients (6%) could not be evaluated due to severe motion artifacts during dipyridamole MRI. Segmental wall motion and perfusion of corresponding short axis planes were related to the major coronary arteries using a standardized segmental coronary artery perfusion pattern. Detection of wall motion abnormalities or perfusion defects by 2 blinded observers in consensus was the criterion for grading a segment normal or pathologic. For localization of CAD, segmental gradings were related to the presumed coronary artery territories. Stress-ECG was pathologic in 19/31 patients yielding a sensitivity of 61% and dipyridamole induced angina was present in 68% (21/31) of patients. Dipyridamole-MRI detected coronary artery disease with a sensitivity of 84% (26/31 patients) and all patients with new wall motion abnormalities also had dipyridamole induced angina. For the subgroup of 20 patients with MIBI-SPECT images, CAD was detected by both MIBI-SPECT and Dipyridamole-MRI in 90% (18/20) of patients. Dipyridamole-MRI and MIBI-SPECT gradings agreed in 55/60 (92%) coronary artery perfusion territories. There were no significant differences with respect to the sensitivities of Dipyridamole-MRI/MIBI-SPECT for the localization of individual coronary artery stenoses yielding 81%/78% for left anterior descending, 80%/80% for left circumflex and 92%/89% for right coronary artery stenoses. However, specificity of Dipyridamole-MRI (89%) for the detection of RCA stenoses was slightly better than for MIBI-SPECT (80%).
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Affiliation(s)
- F M Baer
- Klink III für Innere Medizin, Universität zu Köln, Germany
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van Rossum AC, Galjee MA, Doesburg T, Hofman M, Valk J. The role of magnetic resonance in the evaluation of functional results after CABG/PTCA. INTERNATIONAL JOURNAL OF CARDIAC IMAGING 1993; 9 Suppl 1:59-69. [PMID: 8409545 DOI: 10.1007/bf01143147] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Magnetic resonance imaging (MRI) is a non-invasive modality which can be used for direct visualization of coronary artery bypass grafts. Spin-echo and gradient-echo (cine-MRI) techniques are now available on standard MR machines and provide information on graft morphology and graft patency with a 90% accuracy. By combining the standard techniques with MR phase velocity mapping, the flow rate in the graft can be measured, thereby offering a unique non-invasive assessment of the graft function. Newer techniques include MR coronary angiography, pharmacologically induced stress MRI, ultrafast MRI of the first-pass (perfusion) of a paramagnetic contrast agent through the myocardium, and 31P MR spectroscopy of high-energy phosphate metabolism of the myocardium. All of these may develop into valuable diagnostic tools for the assessment of functional results after CABG or PTCA, but still require clinical validation. At present, MRI is a useful screening procedure for assessment of graft patency and function in post-operative pain syndromes and in late graft occlusion or stenosis.
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Affiliation(s)
- A C van Rossum
- Department of Cardiology, Free University Hospital Amsterdam, The Nethelands
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