101
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Advancing CT and MR imaging of the lungs and airways in children: imaging into practice. Pediatr Radiol 2008; 38 Suppl 2:S208-12. [PMID: 18401613 DOI: 10.1007/s00247-008-0767-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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102
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Abstract
Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled multi-detector row CT allow for quantification of presence and distribution of parenchymal and airway pathology; xenon gas can be employed to assess regional ventilation of the lungs, and rapid bolus injections of iodinated contrast agent can provide a quantitative measure of regional parenchymal perfusion. Advances in MRI of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized gas imaging, which allow functional assessment, including ventilation/perfusion, microscopic air space measurements, and gas flow and transport dynamics.
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Affiliation(s)
- Edwin J R van Beek
- Department of Radiology, Carver College of Medicine, University of Iowa, C-751 GH, 200 Hawkins Drive, Iowa City, IA 52242-1077, USA.
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103
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Ohno Y, Hatabu H. Basics concepts and clinical applications of oxygen-enhanced MR imaging. Eur J Radiol 2007; 64:320-8. [PMID: 17980535 DOI: 10.1016/j.ejrad.2007.08.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 07/31/2007] [Accepted: 08/01/2007] [Indexed: 10/22/2022]
Abstract
Oxygen-enhanced MR imaging is a new technique, and its physiological significance has not yet been fully elucidated. This review article covers (1) the theory of oxygen enhancement and its relationship with respiratory physiology; (2) design for oxygen-enhanced MR imaging sequencing; (3) a basic study of oxygen-enhanced MR imaging in animal models and humans; (4) a clinical study of oxygen-enhanced MR imaging; and (5) a comparison of advantages and disadvantages of this technique with those of hyperpolarized noble gas MR ventilation imaging. Oxygen-enhanced MR imaging provides not only the ventilation-related, but also respiration-related information. Oxygen-enhanced MR imaging has the potential to replace nuclear medicine studies for the identification of regional pulmonary function, and many investigators are now attempting to adapt this technique for routine clinical studies. We believe that further basic studies as well as clinical applications of this new technique will define the real significance of oxygen-enhanced MR imaging for the future of pulmonary functional imaging and its usefulness for diagnostic radiology and pulmonary medicine.
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Affiliation(s)
- Yoshiharu Ohno
- Department of Radiology, Kobe University School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
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104
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Assessment of Morphological MRI for Pulmonary Changes in Cystic Fibrosis (CF) Patients. Invest Radiol 2007; 42:715-25. [DOI: 10.1097/rli.0b013e318074fd81] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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105
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Baum S. Need for rapid communication. Acad Radiol 2007; 14:1009-10. [PMID: 17707306 DOI: 10.1016/j.acra.2007.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 07/17/2007] [Accepted: 07/17/2007] [Indexed: 11/20/2022]
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106
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Fain SB, Korosec FR, Holmes JH, O'Halloran R, Sorkness RL, Grist TM. Functional lung imaging using hyperpolarized gas MRI. J Magn Reson Imaging 2007; 25:910-23. [PMID: 17410561 DOI: 10.1002/jmri.20876] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The noninvasive assessment of lung function using imaging is increasingly of interest for the study of lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Hyperpolarized gas MRI (HP MRI) has demonstrated the ability to detect changes in ventilation, perfusion, and lung microstructure that appear to be associated with both normal lung development and disease progression. The physical characteristics of HP gases and their application to MRI are presented with an emphasis on current applications. Clinical investigations using HP MRI to study asthma, COPD, cystic fibrosis, pediatric chronic lung disease, and lung transplant are reviewed. Recent advances in polarization, pulse sequence development for imaging with Xe-129, and prototype low magnetic field systems dedicated to lung imaging are highlighted as areas of future development for this rapidly evolving technology.
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Affiliation(s)
- Sean B Fain
- Department of Medical Physics, University of Wisconsin, Madison, WI 53792, USA.
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107
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Parraga G, Ouriadov A, Evans A, McKay S, Lam WW, Fenster A, Etemad-Rezai R, McCormack D, Santyr G. Hyperpolarized 3He Ventilation Defects and Apparent Diffusion Coefficients in Chronic Obstructive Pulmonary Disease. Invest Radiol 2007; 42:384-91. [PMID: 17507809 DOI: 10.1097/01.rli.0000262571.81771.66] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Hyperpolarized 3He magnetic resonance imaging (3He MRI) at 3.0 Tesla of healthy volunteers and chronic obstructive pulmonary disease (COPD) patients was performed for quantitative evaluation of ventilation defects and apparent diffusion coefficients (ADC) and for comparison to published results acquired at 1.5 Tesla. The reproducibility of 3He ADC and ventilation defects was also assessed in subjects scanned 3 times, twice within 10 minutes, and again within 7 +/- 2 days of the first MRI visit. MATERIALS AND METHODS Hyperpolarized 3He MRI was performed in 6 subjects. Two interleaved images with and without additional diffusion sensitization were acquired with the first image serving as a ventilation image from which defect score and volume were measured and the combination of the 2 images used to compute ADC maps and ADC histograms. RESULTS He MRI at 3.0 Tesla showed increased mean ADC and ADC standard deviation for subjects with COPD compared with healthy volunteers (ADC healthy volunteer (0.24 +/- 0.12 cm2/s), mild-moderate COPD (0.34 +/- 0.14 cm2/s), and severe COPD (0.47 +/- 0.21 cm2/s), and these values were similar to previously reported results acquired at 1.5 Tesla. Reproducibility of mean ADC was high (coefficient of variation 2% in severe COPD, 3% in mild-moderate COPD, 4% in healthy volunteers) across all 3 scans. Higher same-day scan reproducibility was observed for ventilation defect volume compared with 1-week scan reproducibility in this small group of subjects. CONCLUSIONS ADC values for emphysematous lungs were significantly increased compared with healthy lungs in age-matched subjects, and all values were comparable to those reported previously at 1.5 Tesla. Ventilation defect score and ventilation defect volume results were also comparable to results previously reported in COPD subjects Reproducibility of ADC for same-day scan-rescan and 7-day rescan was high and similar to previously reported results.
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Affiliation(s)
- Grace Parraga
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.
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108
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Abstract
In the last 2 decades significant strides have been made in the application of chest imaging modalities to assess cystic fibrosis (CF) lung disease. This article covers current chest imaging modalities. It discusses CT, the research modality most commonly used to assess lung disease in CF, new insights regarding CF lung disease, and future directions in research and clinical care.
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Affiliation(s)
- Terry E Robinson
- Department of Pediatrics, Center of Excellence in Pulmonary Biology (Pulmonary Division), Stanford University Medical Center, 770 Welch Road,Palo Alto, CA 94304-5715, USA.
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109
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Driehuys B, Hedlund LW. Imaging techniques for small animal models of pulmonary disease: MR microscopy. Toxicol Pathol 2007; 35:49-58. [PMID: 17325972 PMCID: PMC2747380 DOI: 10.1080/01926230601132048] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In vivo magnetic resonance microscopy (MRM) of the small animal lung has become a valuable research tool, especially for preclinical studies. MRM offers a noninvasive and nondestructive tool for imaging small animals longitudinally and at high spatial resolution. We summarize some of the technical and biologic problems and solutions associated with imaging the small animal lung and describe several important pulmonary disease applications. A major advantage of MR is direct imaging of the gas spaces of the lung using breathable gases such as helium and xenon. When polarized, these gases become rich MR signal sources. In animals breathing hyperpolarized helium, the dynamics of gas distribution can be followed and airway constrictions and obstructions can be detected. Diffusion coefficients of helium can be calculated from diffusion-sensitive images, which can reveal micro-structural changes in the lungs associated with pathologies such as emphysema and fibrosis. Unlike helium, xenon in the lung is absorbed by blood and exhibits different frequencies in gas, tissue, or erythrocytes. Thus, with MR imaging, the movement of xenon gas can be tracked through pulmonary compartments to detect defects of gas transfer. MRM has become a valuable tool for studying morphologic and functional changes in small animal models of lung diseases.
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Affiliation(s)
- Bastiaan Driehuys
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710, USA.
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110
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Aziz ZA, Davies JC, Alton EW, Wells AU, Geddes DM, Hansell DM. Computed tomography and cystic fibrosis: promises and problems. Thorax 2007; 62:181-6. [PMID: 17287306 PMCID: PMC2111250 DOI: 10.1136/thx.2005.054379] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Computed tomography (CT) has two potential roles in the evaluation of patients with cystic fibrosis (CF) lung disease: as a diagnostic test primarily for the detection of supervening complications and as a monitoring tool in clinical research. Interest in the latter role has gained momentum in the last 5 years because of two factors: (1) therapeutic options for CF lung disease are developing rapidly, hence the need for an outcome measure that can be applied in clinical intervention trials; and (2) it has become clear that traditional outcome measures such as pulmonary function tests are relatively insensitive to the early structural damage that occurs in CF. Several recent studies have shown that CT can be used as a potential surrogate outcome measure, although its suitability for this specific role is controversial and still under investigation. This review summarises current concepts relating to the research applications of CT in CF, with particular emphasis on the evidence supporting the use of CT as a surrogate outcome measure in clinical trials.
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Affiliation(s)
- Z A Aziz
- Department of Radiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
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111
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Hopkins SR, Levin DL, Emami K, Kadlecek S, Yu J, Ishii M, Rizi RR. Advances in magnetic resonance imaging of lung physiology. J Appl Physiol (1985) 2006; 102:1244-54. [PMID: 17158249 DOI: 10.1152/japplphysiol.00738.2006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review presents an overview of some recent magnetic resonance imaging (MRI) techniques for measuring aspects of local physiology in the lung. MRI is noninvasive, relatively high resolution, and does not expose subjects to ionizing radiation. Conventional MRI of the lung suffers from low signal intensity caused by the low proton density and the large degree of microscopic field inhomogeneity that degrades the magnetic resonance signal and interferes with image acquisition. However, in recent years, there have been rapid advances in both hardware and software design, allowing these difficulties to be minimized. This review focuses on some newer techniques that measure regional perfusion, ventilation, gas diffusion, ventilation-to-perfusion ratio, partial pressure of oxygen, and lung water. These techniques include contrast-enhanced and arterial spin-labeling techniques for measuring perfusion, hyperpolarized gas techniques for measuring regional ventilation, and apparent diffusion coefficient and multiecho and gradient echo techniques for measuring proton density and lung water. Some of the major advantages and disadvantages of each technique are discussed. In addition, some of the physiological issues associated with making measurements are discussed, along with strategies for understanding large and complex data sets.
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Affiliation(s)
- Susan R Hopkins
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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112
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de Lange EE, Altes TA, Patrie JT, Gaare JD, Knake JJ, Mugler JP, Platts-Mills TA. Evaluation of Asthma With Hyperpolarized Helium-3 MRI. Chest 2006; 130:1055-62. [PMID: 17035438 DOI: 10.1378/chest.130.4.1055] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Accurate characterization of asthma severity is difficult due to the variability of symptoms. Hyperpolarized helium-3 MRI (H(3)HeMR) is a new technique in which the airspaces are visualized, depicting regions with airflow obstruction as "ventilation defects." The objective of this study was to compare the extent of H(3)HeMR ventilation defects with measures of asthma severity and spirometry. METHODS Patients with a physician diagnosis of asthma and normal control subjects underwent H(3)HeMR. For each person, the number and size of ventilation defects were scored and the average number of ventilation defects per slice (VDS) was calculated. The correlations of the imaging findings with measures of asthma severity and spirometry were determined. RESULTS There were 58 patients with asthma (mild-intermittent, n = 13; mild-persistent, n = 13; moderate-persistent, n = 20; and severe-persistent, n = 12) and 18 control subjects. Mean +/- SE VDS for asthmatics was significantly greater than for control subjects (0.99 +/- 0.15 vs 0.26 +/- 0.22, p = 0.004). Among asthmatics, VDS was significantly higher for the group with moderate-persistent and severe-persistent disease than for the group with mild-intermittent and mild-persistent disease (1.37 +/- 0.24 vs 0.53 +/- 0.12, p < 0.001). VDS correlated significantly with FEV(1)/FVC (r = - 0.51, p = 0.002), forced expiratory flow between 25% and 75% from the beginning of FVC (FEF(25-75%)) percentage of predicted for height, sex, and race (%predicted) [r = - 0.50, p = 0.001], and FEV(1) %predicted (r = - 0.40, p = 0.002), but not with FVC %predicted (r = - 0.26, p = 0.057) and peak expiratory flow %predicted (r = - 0.16, p = 0.231). Many asthmatics had an elevated VDS, but their spirometric indexes, except FEF(25%-75%), were normal. Most ventilation defects were < 3 cm in size for all asthmatics. In the group of patients with moderate-to-severe persistent asthma, there were more defects > or =3 cm than in the group with mild-intermittent and mild-persistent disease (p = 0.021). CONCLUSIONS Regional changes of airflow obstruction in asthmatics depicted by H(3)HeMR correlate with measures of asthma severity and spirometry.
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Affiliation(s)
- Eduard E de Lange
- University of Virginia Health Sciences System, Department of Radiology, HSC 800170, Charlottesville, VA 22908, USA.
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113
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van Beek EJR, Hill C, Woodhouse N, Fichele S, Fleming S, Howe B, Bott S, Wild JM, Taylor CJ. Assessment of lung disease in children with cystic fibrosis using hyperpolarized 3-Helium MRI: comparison with Shwachman score, Chrispin-Norman score and spirometry. Eur Radiol 2006; 17:1018-24. [PMID: 16941089 DOI: 10.1007/s00330-006-0392-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 06/19/2006] [Accepted: 07/07/2006] [Indexed: 11/29/2022]
Abstract
This study assesses the feasibility of hyperpolarized 3-Helium MRI in children with cystic fibrosis (CF) and correlates the findings with standard clinical parameters based on chest radiograph (CXR) and pulmonary function tests (PFT). An uncontrolled, observational study in eighteen children with cystic fibrosis aged 5 - 17 years (median 12.1 years), with different severity of disease was carried out. All subjects underwent routine clinical assessment including PFT and standard auxology; CXR was obtained and Shwachman and Chrispin-Norman scores calculated. Hyperpolarized 3-He magnetic resonance imaging (MRI) was carried out using a spin-exchange polarizer and a whole body 1.5 T scanner. Ventilation distribution images were obtained during a 21-second breath-hold and scored according to previously defined criteria. Spearman's non-parametric correlations test was performed to assess for statistical significance at the p<0.05 level. The children tolerated the procedure well. No desaturation events were observed during 3-He MRI. A significant, albeit moderate, correlation was found between MRI score and FEV1% predicted (r=-0.41; p=0.047) and FVC% predicted (r=-0.42; p=0.04), while there were trends of correlations between Shwachman score and MRI score (r=-0.38; p=0.06) and Shwachman score and FEV1% predicted (r=0.39; p=0.055). The feasibility of hyperpolarized 3-He MRI in children with CF was demonstrated. MRI appears to be able to demonstrate functional lung changes, although correlations with routine clinical tests are only moderate to poor. This non-ionising radiation technique could be useful for monitoring lung disease and assessing therapy in this patient population.
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114
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McMahon CJ, Dodd JD, Hill C, Woodhouse N, Wild JM, Fichele S, Gallagher CG, Skehan SJ, van Beek EJR, Masterson JB. Hyperpolarized 3helium magnetic resonance ventilation imaging of the lung in cystic fibrosis: comparison with high resolution CT and spirometry. Eur Radiol 2006; 16:2483-90. [PMID: 16871384 DOI: 10.1007/s00330-006-0311-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 04/20/2006] [Accepted: 04/21/2006] [Indexed: 01/08/2023]
Abstract
The purpose of this study was to compare hyperpolarized 3helium magnetic resonance imaging (3He MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent 3He MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized 3He. Each lung was divided into six zones; 3He MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between 3He MRI, HRCT, and spirometry. Results are expressed as mean+/-SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age = 31.9+/-9 (20-46). Mean forced expiratory volume in 1 s (FEV)1 = 52%+/-29 (27-93). Mean 3He MRI score = 74%+/-25 (55-100). Mean HRCT score = 48.8+/-24 (13.5-83). The correlation between 3He MRI and HRCT was strong (R = +/-0.89, p < 0.001). Bronchiectasis was the only independent predictor of 3He MRI; 3He MRI correlated better with FEV1 and forced vital capacity (FVC) (R = 0.86 and 0.93, p < 0.01, respectively) than HRCT (R = +/-0.72 and +/-0.81, p < 0.05, respectively). This study showed that 3He MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF.
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Affiliation(s)
- Colm J McMahon
- Department of Radiology, St. Vincent's University Hospital, Dublin 4, Ireland.
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115
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Proceedings from the 2004 International Workshop on Functional Pulmonary Imaging, Philadelphia, Pennsylvania, USA. Acad Radiol 2005; 12:1357-463. [PMID: 16253846 DOI: 10.1016/j.acra.2005.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 08/17/2005] [Accepted: 08/17/2005] [Indexed: 10/25/2022]
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