1
|
Hamedani H, Kadlecek S, Ruppert K, Xin Y, Duncan I, Rizi RR. Ventilation heterogeneity imaged by multibreath wash-ins of hyperpolarized 3 He and 129 Xe in healthy rabbits. J Physiol 2021; 599:4197-4223. [PMID: 34256417 DOI: 10.1113/jp281584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/30/2021] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Multibreath imaging to estimate regional gas mixing efficiency is superior to intensity-based single-breath ventilation markers, as it is capable of revealing minute but essential measures of ventilation heterogeneity which may be sensitive to subclinical alterations in the early stages of both obstructive and restrictive respiratory disorders. Large-scale convective stratification of ventilation in central-to-peripheral directions is the dominant feature of observed ventilation heterogeneity when imaging a heavy/less diffusive xenon gas mixture; smaller-scale patchiness, probably originating from asymmetric lung function at bronchial airway branching due to the interaction of convective and diffusive flows, is the dominant feature when imaging a lighter/more diffusive helium gas mixture. Since detecting low regional ventilation is crucial for characterizing diseased lungs, our results suggest that dilution with natural abundance helium and imaging at higher lung volumes seem advisable when imaging with hyperpolarized 129 Xe; this will allow the imaging gas to reach slow-filling and/or non-dependent lung regions, which might otherwise be impossible to distinguish from total ventilation shunt regions. The ability to differentiate these regions from those of total shunt is worse with typical single-breath imaging techniques. ABSTRACT The mixing of freshly inhaled gas with gas already present in the lung can be directly assessed with heretofore unachievable precision via magnetic resonance imaging of signal build-up resulting from multiple wash-ins of a hyperpolarized (HP) gas. Here, we used normoxic HP 3 He and 129 Xe mixtures to study regional ventilation at different spatial scales in five healthy mechanically ventilated supine rabbits at two different inspired volumes. To decouple the respective effects of density and diffusion rates on ventilation heterogeneity, two additional studies were performed: one in which 3 He was diluted with an equal fraction of natural abundance xenon, and one in which 129 Xe was diluted with an equal fraction of 4 He. We observed systematic differences in the spatial scale of specific ventilation heterogeneity between HP 3 He and 129 Xe. We found that large-scale, central-to-peripheral convective ventilation inhomogeneity is the dominant cause of observed heterogeneity when breathing a normoxic xenon gas mixture. In contrast, small-scale ventilation heterogeneity in the form of patchiness, probably originating from asymmetric lung function at bronchial airway branching due to interactions between convective and diffusive flows, is the dominant feature when breathing a normoxic helium gas mixture, for which the critical zone occurs more proximally and at an imageable spatial scale. We also showed that the existence of particular underventilated non-dependent lung regions when breathing a heavy gas mixture is the result of the density of that mixture - rather than, for example, its diffusion rate or viscosity. Finally, we showed that gravity-dependent ventilation heterogeneity becomes substantially more uniform at higher inspired volumes for xenon gas mixtures compared to helium mixtures.
Collapse
Affiliation(s)
- Hooman Hamedani
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Penn Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen Kadlecek
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kai Ruppert
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi Xin
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Penn Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian Duncan
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rahim R Rizi
- Department of Radiology, Functional and Metabolic Imaging Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|
2
|
Ohno Y, Hanamatsu S, Obama Y, Ueda T, Ikeda H, Hattori H, Murayama K, Toyama H. Overview of MRI for pulmonary functional imaging. Br J Radiol 2021; 95:20201053. [PMID: 33529053 DOI: 10.1259/bjr.20201053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Morphological evaluation of the lung is important in the clinical evaluation of pulmonary diseases. However, the disease process, especially in its early phases, may primarily result in changes in pulmonary function without changing the pulmonary structure. In such cases, the traditional imaging approaches to pulmonary morphology may not provide sufficient insight into the underlying pathophysiology. Pulmonary imaging community has therefore tried to assess pulmonary diseases and functions utilizing not only nuclear medicine, but also CT and MR imaging with various technical approaches. In this review, we overview state-of-the art MR methods and the future direction of: (1) ventilation imaging, (2) perfusion imaging and (3) biomechanical evaluation for pulmonary functional imaging.
Collapse
Affiliation(s)
- Yoshiharu Ohno
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan.,Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan
| | - Satomu Hanamatsu
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Yuki Obama
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Takahiro Ueda
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Hirotaka Ikeda
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Hidekazu Hattori
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Kazuhiro Murayama
- Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan
| | - Hiroshi Toyama
- Department of Radiology, Fujita Health University, School of Medicine, Toyoake, Japan
| |
Collapse
|
3
|
Gammon ST, Foje N, Brewer EM, Owers E, Downs CA, Budde MD, Leevy WM, Helms MN. Preclinical anatomical, molecular, and functional imaging of the lung with multiple modalities. Am J Physiol Lung Cell Mol Physiol 2014; 306:L897-914. [DOI: 10.1152/ajplung.00007.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In vivo imaging is an important tool for preclinical studies of lung function and disease. The widespread availability of multimodal animal imaging systems and the rapid rate of diagnostic contrast agent development have empowered researchers to noninvasively study lung function and pulmonary disorders. Investigators can identify, track, and quantify biological processes over time. In this review, we highlight the fundamental principles of bioluminescence, fluorescence, planar X-ray, X-ray computed tomography, magnetic resonance imaging, and nuclear imaging modalities (such as positron emission tomography and single photon emission computed tomography) that have been successfully employed for the study of lung function and pulmonary disorders in a preclinical setting. The major principles, benefits, and applications of each imaging modality and technology are reviewed. Limitations and the future prospective of multimodal imaging in pulmonary physiology are also discussed. In vivo imaging bridges molecular biological studies, drug design and discovery, and the imaging field with modern medical practice, and, as such, will continue to be a mainstay in biomedical research.
Collapse
Affiliation(s)
- Seth T. Gammon
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Nathan Foje
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - Elizabeth M. Brewer
- Department of Pediatrics Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| | - Elizabeth Owers
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - Charles A. Downs
- Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, Georgia; and
| | - Matthew D. Budde
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - W. Matthew Leevy
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - My N. Helms
- Department of Pediatrics Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| |
Collapse
|
4
|
Kyriazis A, Rodriguez I, Nin N, Izquierdo-Garcia JL, Lorente JA, Perez-Sanchez JM, Pesic J, Olsson LE, Ruiz-Cabello J. Dynamic ventilation 3He MRI for the quantification of disease in the rat lung. IEEE Trans Biomed Eng 2011; 59:777-86. [PMID: 22167560 DOI: 10.1109/tbme.2011.2179299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Pulmonary diseases are known to be largely inhomogeneous. To evaluate such inhomogeneities, we are testing an image-based method to measure gas flow in the lung regionally. Dynamic, spin-density-weighted hyperpolarized (3)He MR images performed during slow inhalation of this gas were analyzed to quantify regional inflation rate. This parameter was measured in regions of interest (ROIs) that were defined by a rectangular grid that covered the entire rat lung and grew dynamically with it during its inflation. We used regional inflation rate to quantify elastase-induced emphysema and to differentiate healthy (n = 8) from elastase-treated (n = 9) rat lungs as well as healthy from elastase-treated areas of one rat unilaterally treated with elastase in the left lung. Emphysema was also assessed by gold standard morphological and well-established hyperpolarized (3)He MRI diffusion measurements. Mean values of regional inflation rates were significantly different for healthy and elastase-treated animals and correlated well with the apparent diffusion coefficient of (3)He and morphological measurements. The image-based biomarker inflation rate may be useful for the assessment of regional lung ventilation.
Collapse
Affiliation(s)
- Angelos Kyriazis
- Department of Chemistry-Physics II, Faculty of Pharmacy, Complutense University of Madrid, Madrid 28040, Spain.
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Mazzanti ML, Walvick RP, Zhou X, Sun Y, Shah N, Mansour J, Gereige J, Albert MS. Distribution of hyperpolarized xenon in the brain following sensory stimulation: preliminary MRI findings. PLoS One 2011; 6:e21607. [PMID: 21789173 PMCID: PMC3137603 DOI: 10.1371/journal.pone.0021607] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022] Open
Abstract
In hyperpolarized xenon magnetic resonance imaging (HP (129)Xe MRI), the inhaled spin-1/2 isotope of xenon gas is used to generate the MR signal. Because hyperpolarized xenon is an MR signal source with properties very different from those generated from water-protons, HP (129)Xe MRI may yield structural and functional information not detectable by conventional proton-based MRI methods. Here we demonstrate the differential distribution of HP (129)Xe in the cerebral cortex of the rat following a pain stimulus evoked in the animal's forepaw. Areas of higher HP (129)Xe signal corresponded to those areas previously demonstrated by conventional functional MRI (fMRI) methods as being activated by a forepaw pain stimulus. The percent increase in HP (129)Xe signal over baseline was 13-28%, and was detectable with a single set of pre and post stimulus images. Recent innovations in the production of highly polarized (129)Xe should make feasible the emergence of HP (129)Xe MRI as a viable adjunct method to conventional MRI for the study of brain function and disease.
Collapse
Affiliation(s)
- Mary L. Mazzanti
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ronn P. Walvick
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xin Zhou
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Yanping Sun
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Lurie Family Imaging Center, Center for Biomedical Imaging in Oncology, Dana Farber Cancer Institute, Massachusetts, United States of America
| | - Niral Shah
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joey Mansour
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica Gereige
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mitchell S. Albert
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada
| |
Collapse
|
6
|
Zurek M, Crémillieux Y. MRI of the lung: non-invasive protocols and applications to small animal models of lung disease. Methods Mol Biol 2011; 771:459-474. [PMID: 21874493 DOI: 10.1007/978-1-61779-219-9_24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Magnetic resonance imaging (MRI) can be used in pre-clinical studies as a non-invasive imaging tool for assessing the morphological and functional impact of lung diseases and for evaluating the efficacy of potential treatments for airways diseases. Hyperpolarized gases ((3)He or (129)Xe) MRI provides insight into the lung ventilation function. Lung proton MRI provides information on lung diseases associated with inflammatory activity or with changes in lung tissue density. These imaging techniques can be implemented with non-invasive protocols appropriate for longitudinal investigations in small animal models of lung diseases. This chapter will detail two (3)He and proton lung MR imaging protocols applied on two models of lung pathology in rodents.
Collapse
|
7
|
Beckmann N, Cannet C, Karmouty-Quintana H, Tigani B, Zurbruegg S, Blé FX, Crémillieux Y, Trifilieff A. Lung MRI for experimental drug research. Eur J Radiol 2007; 64:381-96. [PMID: 17931813 DOI: 10.1016/j.ejrad.2007.08.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [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
Current techniques to evaluate the efficacy of potential treatments for airways diseases in preclinical models are generally invasive and terminal. In the past few years, the flexibility of magnetic resonance imaging (MRI) to obtain anatomical and functional information of the lung has been explored with the scope of developing a non-invasive approach for the routine testing of drugs in models of airways diseases in small rodents. With MRI, the disease progression can be followed in the same animal. Thus, a significant reduction in the number of animals used for experimentation is achieved, as well as minimal interference with their well-being and physiological status. In addition, under certain circumstances the duration of the observation period after disease onset can be shortened since the technique is able to detect changes before these are reflected in parameters of inflammation determined using invasive procedures. The objective of this article is to briefly address MRI techniques that are being used in experimental lung research, with special emphasis on applications. Following an introduction on proton techniques and MRI of hyperpolarized gases, the attention is shifted to the MRI analysis of several aspects of lung disease models, including inflammation, ventilation, emphysema, fibrosis and sensory nerve activation. The next subject concerns the use of MRI in pharmacological studies within the context of experimental lung research. A final discussion points towards advantages and limitations of MRI in this area.
Collapse
Affiliation(s)
- Nicolau Beckmann
- Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel, Switzerland.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Benrath J, Kempf C, Georgieff M, Sandkühler J. Xenon blocks the induction of synaptic long-term potentiation in pain pathways in the rat spinal cord in vivo. Anesth Analg 2007; 104:106-11. [PMID: 17179253 DOI: 10.1213/01.ane.0000250368.27822.31] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Xenon's (Xe) mechanisms for producing anesthesia and analgesia are not fully understood. We tested the effect of Xe equilibrated in a lipid formulation or normal saline on spinal C-fiber-evoked potentials and on the induction of synaptic long-term potentiation (LTP). METHODS C-fiber-evoked field potentials were recorded in the superficial lumbar spinal cord in response to supramaximal electrical stimulation of the sciatic nerve. Anesthesia was maintained with isoflurane in one-third O2 and two-thirds N2O. Xe equilibrated at a concentration of 600 microL/mL of Lipofundin MCT(R) 20%, (n = 5) or solvent alone (n = 3), and Xe equilibrated at a concentration of 100 microL/mL of normal saline (n = 7) or saline alone (n = 7) was given IV under apnea. High-frequency stimulation of the sciatic nerve was applied 60 min after the injection of Xe-containing formulations or solvents [to induce LTP]. RESULTS High-frequency stimulation potentiated C-fiber-evoked potentials to 156% +/- 14% (mean +/- sem) of control. Low-dose Xe in saline 0.9% blocked the induction of LTP. High-dose Xe equilibrated in MC(R) 20% showed no additional effect when compared with the solvent, which blocked the induction of LTP. CONCLUSION Low-dose Xe in saline 0.9% revealed no antinociceptive, but preventive, action in spinal pain pathways.
Collapse
Affiliation(s)
- Justus Benrath
- Klinische Abteilung für Anästhesie und Allgemeine Intensivmedizin B, Medizinische Universität Wien, Währinger Gürtel 18-20, AKH, A-1090 Wien, Austria
| | | | | | | |
Collapse
|
9
|
Pavlovskaya GE, Cleveland ZI, Stupic KF, Basaraba RJ, Meersmann T. Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging. Proc Natl Acad Sci U S A 2005; 102:18275-9. [PMID: 16344474 PMCID: PMC1317982 DOI: 10.1073/pnas.0509419102] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Indexed: 11/18/2022] Open
Abstract
For the first time, magnetic resonance imaging (MRI) with hyperpolarized (hp) krypton-83 (83Kr) has become available. The relaxation of the nuclear spin of 83Kr atoms (I = 9/2) is driven by quadrupolar interactions during brief adsorption periods on surrounding material interfaces. Experiments in model systems reveal that the longitudinal relaxation of hp 83Kr gas strongly depends on the chemical composition of the materials. The relaxation-weighted contrast in hp 83Kr MRI allows for the distinction between hydrophobic and hydrophilic surfaces. The feasibility of hp 83Kr MRI of airways is tested in canine lung tissue by using krypton gas with natural abundance isotopic distribution. Additionally, the influence of magnetic field strength and the presence of a breathable concentration of molecular oxygen on longitudinal relaxation are investigated.
Collapse
|
10
|
Månsson S, Deninger AJ, Magnusson P, Pettersson G, Olsson LE, Hansson G, Wollmer P, Golman K. 3He MRI-based assessment of posture-dependent regional ventilation gradients in rats. J Appl Physiol (1985) 2005; 98:2259-67. [PMID: 15640396 DOI: 10.1152/japplphysiol.00245.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A recently developed method for quantitative assessment of regional lung ventilation was employed for the study of posture-dependent ventilation differences in rats. The measurement employed hyperpolarized (3)He MRI to detect the build-up of the signal intensity after increasing numbers of (3)He breaths, which allowed for computation of a regional ventilation parameter. A group of six anesthetized rats was studied in both supine and prone postures. Three-dimensional maps of the ventilation parameter were obtained with high spatial resolution (voxel volume approximately 2 mm(3)). Vertical (dorsal-ventral) gradients of the ventilation index, defined as the regional ventilation normalized by the average ventilation within the whole lung, were investigated. Variations in the regional distribution of the ventilation parameter, as well as of the ventilation index, could be detected, depending on the posture of the rats. In supine posture, ventilation was elevated in the dependent parts of the lungs, with a linear gradient of the ventilation index of -0.11 +/- 0.03 cm(-1). In prone posture, the distribution of ventilation was more uniform, with a significantly (P < 0.001) smaller gradient of the ventilation index of -0.01 +/- 0.02 cm(-1). It is concluded that the (3)He MRI-based method can detect and quantify regional ventilation gradients in animals as small as the rat and that these gradients depend on prone or supine posture of the animal.
Collapse
Affiliation(s)
- Sven Månsson
- Dept. of Experimental Research, Malmö Univ. Hospital, SE-205 02 Malmö, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Möller HE, Chen XJ, Saam B, Hagspiel KD, Johnson GA, Altes TA, de Lange EE, Kauczor HU. MRI of the lungs using hyperpolarized noble gases. Magn Reson Med 2002; 47:1029-51. [PMID: 12111949 DOI: 10.1002/mrm.10173] [Citation(s) in RCA: 273] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The nuclear spin polarization of the noble gas isotopes (3)He and (129)Xe can be increased using optical pumping methods by four to five orders of magnitude. This extraordinary gain in polarization translates directly into a gain in signal strength for MRI. The new technology of hyperpolarized (HP) gas MRI holds enormous potential for enhancing sensitivity and contrast in pulmonary imaging. This review outlines the physics underlying the optical pumping process, imaging strategies coping with the nonequilibrium polarization, and effects of the alveolar microstructure on relaxation and diffusion of the noble gases. It presents recent progress in HP gas MRI and applications ranging from MR microscopy of airspaces to imaging pulmonary function in patients and suggests potential directions for future developments.
Collapse
Affiliation(s)
- Harald E Möller
- Max-Planck-Institut für neuropsychologische Forschung, Leipzig, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Kauczor HU. Current issues in hyperpolarized gases in MRI: biomedical investigations and clinical applications. NMR IN BIOMEDICINE 2000; 13:173-175. [PMID: 10867692 DOI: 10.1002/1099-1492(200006)13:4<173::aid-nbm631>3.0.co;2-p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- H U Kauczor
- Klinik fuer Radiologie, University of Mainz, Langenbeckstr. 1, D-55131 Mainz, Germany.
| |
Collapse
|