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Wehrse E, Klein L, Rotkopf LT, Stiller W, Finke M, Echner G, Glowa C, Heinze S, Ziener CH, Schlemmer HP, Kachelrieß M, Sawall S. Ultrahigh resolution whole body photon counting computed tomography as a novel versatile tool for translational research from mouse to man. Z Med Phys 2022:S0939-3889(22)00066-6. [PMID: 35868888 DOI: 10.1016/j.zemedi.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/18/2022] [Accepted: 06/19/2022] [Indexed: 11/19/2022]
Abstract
X-ray computed tomography (CT) is a cardinal tool in clinical practice. It provides cross-sectional images within seconds. The recent introduction of clinical photon-counting CT allowed for an increase in spatial resolution by more than a factor of two resulting in a pixel size in the center of rotation of about 150 µm. This level of spatial resolution is in the order of dedicated preclinical micro-CT systems. However so far, the need for different dedicated clinical and preclinical systems often hinders the rapid translation of early research results to applications in men. This drawback might be overcome by ultra-high resolution (UHR) clinical photon-counting CT unifying preclinical and clinical research capabilities in a single machine. Herein, the prototype of a clinical UHR PCD CT (SOMATOM CounT, Siemens Healthineers, Forchheim, Germany) was used. The system comprises a conventional energy-integrating detector (EID) and a novel photon-counting detector (PCD). While the EID provides a pixel size of 0.6 mm in the centre of rotation, the PCD provides a pixel size of 0.25 mm. Additionally, it provides a quantification of photon energies by sorting them into up to four distinct energy bins. This acquisition of multi-energy data allows for a multitude of applications, e.g. pseudo-monochromatic imaging. In particular, we examine the relation between spatial resolution, image noise and administered radiation dose for a multitude of use-cases. These cases include ultra-high resolution and multi-energy acquisitions of mice administered with a prototype bismuth-based contrast agent (nanoPET Pharma, Berlin, Germany) as well as larger animals and actual patients. The clinical EID provides a spatial resolution of about 9 lp/cm (modulation transfer function at 10%, MTF10%) while UHR allows for the acquisition of images with up to 16 lp/cm allowing for the visualization of all relevant anatomical structures in preclinical and clinical specimen. The spectral capabilities of the system enable a variety of applications previously not available in preclinical research such as pseudo-monochromatic images. Clinical ultra-high resolution photon-counting CT has the potential to unify preclinical and clinical research on a single system enabling versatile imaging of specimens and individuals ranging from mice to man.
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Affiliation(s)
- E Wehrse
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Medical Faculty, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | - L Klein
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany; Division of X-ray Imaging and CT, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - L T Rotkopf
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - W Stiller
- Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Heidelberg, Germany
| | - M Finke
- Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Heidelberg, Germany
| | - G Echner
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - C Glowa
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department of Radiation Oncology and Radiotherapy, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - S Heinze
- Institute of Forensic and Traffic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - C H Ziener
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - H-P Schlemmer
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - M Kachelrieß
- Medical Faculty, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Division of X-ray Imaging and CT, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - S Sawall
- Medical Faculty, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Division of X-ray Imaging and CT, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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Arbabi A, Spencer Noakes L, Vousden D, Dazai J, Spring S, Botelho O, Keshavarzian T, Mattingly M, Ellegood JE, Nutter LMJ, Wissmann R, Sled JG, Lerch JP, Henkelman RM, Nieman BJ. Multiple-mouse magnetic resonance imaging with cryogenic radiofrequency probes for evaluation of brain development. Neuroimage 2022; 252:119008. [PMID: 35245675 DOI: 10.1016/j.neuroimage.2022.119008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 11/17/2022] Open
Abstract
Multiple-mouse magnetic resonance imaging (MRI) increases scan throughput by imaging several mice simultaneously in the same magnet bore, enabling multiple images to be obtained in the same time as a single scan. This increase in throughput enables larger studies than otherwise feasible and is particularly advantageous in longitudinal study designs where frequent imaging time points result in high demand for MRI resources. Cryogenically-cooled radiofrequency probes (CryoProbes) have been demonstrated to have significant signal-to-noise ratio benefits over comparable room temperature coils for in vivo mouse imaging. In this work, we demonstrate implementation of a multiple-mouse MRI system using CryoProbes, achieved by mounting four such coils in a 30-cm, 7-Tesla magnet bore. The approach is demonstrated for longitudinal quantification of brain structure from infancy to early adulthood in a mouse model of Sanfilippo syndrome (mucopolysaccharidosis type III), generated by knockout of the Hgsnat gene. We find that Hgsnat-/- mice have regionally increased growth rates compared to Hgsnat+/+ mice in a number of brain regions, notably including the ventricles, amygdala and superior colliculus. A strong sex dependence was also noted, with the lateral ventricle volume growing at an accelerated rate in males, but several structures in the brain parenchyma growing faster in females. This approach is broadly applicable to other mouse models of human disease and the increased throughput may be particularly beneficial in studying mouse models of neurodevelopmental disorders.
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Affiliation(s)
- A Arbabi
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - L Spencer Noakes
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Pre-Therapeutic Target Discovery, Regeneron Pharmaceuticals, Tarrytown, NY, United States
| | - D Vousden
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; DataKind UK, London, UK
| | - J Dazai
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - S Spring
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - O Botelho
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - T Keshavarzian
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - M Mattingly
- Bruker BioSpin Corporation, Billerica, MA, United States
| | - J E Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - L M J Nutter
- The Centre for Phenogenomics, Hospital for Sick Children, Toronto, ON, Canada
| | - R Wissmann
- Bruker BioSpin Corporation, Ettlingen, Germany
| | - J G Sled
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - J P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada; Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - R M Henkelman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - B J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Ontario Institute for Cancer Research, Toronto, ON, Canada.
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Fischbach K, Kosiek O, Friebe B, Wybranski C, Schnackenburg B, Schmeisser A, Smid J, Ricke J, Pech M. Cardiac Magnetic Resonance Imaging Using an Open 1.0T MR Platform: A Comparative Study with a 1.5T Tunnel System. Pol J Radiol 2017; 82:498-505. [PMID: 29662579 PMCID: PMC5894020 DOI: 10.12659/pjr.899822] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 12/06/2016] [Indexed: 11/09/2022] Open
Abstract
Background Cardiac magnetic resonance imaging (cMRI) has become the non-invasive reference standard for the evaluation of cardiac function and viability. The introduction of open, high-field, 1.0T (HFO) MR scanners offers advantages for examinations of obese, claustrophobic and paediatric patients.The aim of our study was to compare standard cMRI sequences from an HFO scanner and those from a cylindrical, 1.5T MR system. Material/Method Fifteen volunteers underwent cMRI both in an open HFO and in a cylindrical MR system. The protocol consisted of cine and unenhanced tissue sequences. The signal-to-noise ratio (SNR) for each sequence and blood-myocardium contrast for the cine sequences were assessed. Image quality and artefacts were rated. The location and number of non-diagnostic segments was determined. Volunteers' tolerance to examinations in both scanners was investigated. Results SNR was significantly lower in the HFO scanner (all p<0.001). However, the contrast of the cine sequence was significantly higher in the HFO platform compared to the 1.5T MR scanner (0.685±0.41 vs. 0.611±0.54; p<0.001). Image quality was comparable for all sequences (all p>0.05). Overall, only few non-diagnostic myocardial segments were recorded: 6/960 (0.6%) by the HFO and 17/960 (1.8%) segments by the cylindrical system. The volunteers expressed a preference for the open MR system (p<0.01). Conclusions Standard cardiac MRI sequences in an HFO platform offer a high image quality that is comparable to the quality of images acquired in a cylindrical 1.5T MR scanner. An open scanner design may potentially improve tolerance of cardiac MRI and therefore allow to examine an even broader patient spectrum.
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Affiliation(s)
- Katharina Fischbach
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
| | - Otrud Kosiek
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
| | - Björn Friebe
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
| | - Christian Wybranski
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
| | | | | | - Jan Smid
- Department of Cardiology, University Clinic, Magdeburg, Germany
| | - Jens Ricke
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
| | - Maciej Pech
- Department of Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, Germany
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Heo P, Seo JH, Han SD, Ryu Y, Byun JD, Kim KN, Lee JH. Multi-port-driven birdcage coil for multiple-mouse MR imaging at 7 T. SCANNING 2016; 38:747-756. [PMID: 27162104 DOI: 10.1002/sca.21324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
In ultra-high field (UHF) imaging environments, it has been demonstrated that multiple-mouse magnetic resonance imaging (MM-MRI) is dependent on key factors such as the radiofrequency (RF) coil hardware, imaging protocol, and experimental setup for obtaining high-resolution MR images. A key aspect is the RF coil, and a number of MM-MRI studies have investigated the application of single-channel RF transmit (Tx)/receive (Rx) coils or multi-channel phased array (PA) coil configurations under a single gradient coil set. However, despite applying a variety of RF coils, Tx (|B1+ |)-field inhomogeneity still remains a major problem due to the relative shortening of the effective RF wavelength in the UHF environment. To address this issue, we propose a relatively smaller size of individual Tx-only coils in a multiple birdcage (MBC) coil for MM-MRI to image up to three mice. We use electromagnetic (EM) simulations in the finite-difference time-domain (FDTD) environment to obtain the |B1 |-field distribution. Our results clearly show that the single birdcage (SBC) high-pass filter (HPF) configuration, which is referred to as the SBCHPF , under the absence of an RF shield exhibits a high |B1 |-field intensity in comparison with other coil configurations such as the low-pass filter (LPF) and band-pass filter (BPF) configurations. In a 7-T MRI experiment, the signal-to-noise ratio (SNR) map of the SBCHPF configuration shows the highest coil performance compared to other coil configurations. The MBCHPF coil, which is comprised of a triple-SBCHPF configuration combined with additional decoupling techniques, is developed for simultaneous image acquisition of three mice. SCANNING 38:747-756, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Phil Heo
- Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Jeung-Hoon Seo
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Sang-Doc Han
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Yeunchul Ryu
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Jong-Deok Byun
- Department of Mechanical and Biomedical Engineering, Gangwon University, Gangwon, Korea
| | - Kyoung-Nam Kim
- Neuroscience Research Institute, Gachon University, Incheon, Korea
- Department of Biomedical Engineering, Gachon University, Incheon, Korea
| | - Jung Hee Lee
- Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Peldschus K, Ittrich H. Magnetic resonance imaging of metastases in xenograft mouse models of cancer. Methods Mol Biol 2014; 1070:213-22. [PMID: 24092443 DOI: 10.1007/978-1-4614-8244-4_16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Magnetic resonance imaging (MRI) of small animals has emerged as a valuable tool to noninvasively monitor tumor growth in mouse models of cancer. However, imaging of metastases in mouse models is difficult due to the need for high spatial resolution. We have demonstrated MRI of metastases in the liver, brain, adrenal glands, and lymph nodes in different xenograft mouse models of cancer. MRI of mice was performed with a clinical 3.0 T magnetic resonance scanner and a commercially available small-animal receiver coil. The imaging protocol consisted of T1- and T2-weighted fat-saturated spin echo sequences with a spatial resolution of 200 μm × 200 μm × 500 μm. Total acquisition time was 30 min per mouse. The technique allowed for repetitive examinations of larger animal cohorts to observe the development of metastases.
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Affiliation(s)
- Kersten Peldschus
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Enders J, Rief M, Zimmermann E, Asbach P, Diederichs G, Wetz C, Siebert E, Wagner M, Hamm B, Dewey M. High-field open versus short-bore magnetic resonance imaging of the spine: a randomized controlled comparison of image quality. PLoS One 2013; 8:e83427. [PMID: 24391767 PMCID: PMC3877023 DOI: 10.1371/journal.pone.0083427] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/01/2013] [Indexed: 12/02/2022] Open
Abstract
Background The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Methods Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. Results The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34–37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). Conclusions In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. Trial Registration ClinicalTrials.gov NCT00715806
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Affiliation(s)
- Judith Enders
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Matthias Rief
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Elke Zimmermann
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Patrick Asbach
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Gerd Diederichs
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Christoph Wetz
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Eberhard Siebert
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Moritz Wagner
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Bernd Hamm
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
| | - Marc Dewey
- Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin and Freie Universität Berlin, Germany
- * E-mail:
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Mitsuda M, Yamaguchi M, Nakagami R, Furuta T, Sekine N, Niitsu M, Moriyama N, Fujii H. Intensity correction method customized for multi-animal abdominal MR imaging with 3T clinical scanner and multi-array coil. Magn Reson Med Sci 2013; 12:95-103. [PMID: 23666151 DOI: 10.2463/mrms.2012-0038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Simultaneous magnetic resonance (MR) imaging of multiple small animals in a single session increases throughput of preclinical imaging experiments. Such imaging using a 3-tesla clinical scanner with multi-array coil requires correction of intensity variation caused by the inhomogeneous sensitivity profile of the coil. We explored a method for correcting intensity that we customized for multi-animal MR imaging, especially abdominal imaging. METHOD Our institutional committee for animal experimentation approved the protocol. We acquired high resolution T₁-, T₂-, and T₂*-weighted images and low resolution proton density-weighted images (PDWIs) of 4 rat abdomens simultaneously using a 3T clinical scanner and custom-made multi-array coil. For comparison, we also acquired T₁-, T₂-, and T₂*-weighted volume coil images in the same rats in 4 separate sessions. We used software created in-house to correct intensity variation. We applied thresholding to the PDWIs to produce binary images that displayed only a signal-producing area, calculated multi-array coil sensitivity maps by dividing low-pass filtered PDWIs by low-pass filtered binary images pixel by pixel, and divided uncorrected T₁-, T₂-, or T₂*-weighted images by those maps to obtain intensity-corrected images. We compared tissue contrast among the liver, spinal canal, and muscle between intensity-corrected multi-array coil images and volume coil images. RESULTS Our intensity correction method performed well for all pulse sequences studied and corrected variation in original multi-array coil images without deteriorating the throughput of animal experiments. Tissue contrasts were comparable between intensity-corrected multi-array coil images and volume coil images. CONCLUSION Our intensity correction method customized for multi-animal abdominal MR imaging using a 3T clinical scanner and dedicated multi-array coil could facilitate image interpretation.
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Affiliation(s)
- Minoru Mitsuda
- Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwanoha 6-5-1, Kashiwa, Chiba 277-8577, Japan
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Ramirez MS, Lai SY, Bankson JA. A throughput-optimized array system for multiple-mouse MRI. NMR IN BIOMEDICINE 2013; 26:237-47. [PMID: 22887122 PMCID: PMC3543508 DOI: 10.1002/nbm.2841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 05/21/2012] [Accepted: 07/11/2012] [Indexed: 05/15/2023]
Abstract
MRI is a versatile tool for the systematic assessment of anatomical and functional changes in small-animal models of human disease. Its noninvasive nature makes it an ideal candidate for longitudinal evaluations of disease progression, but relatively long scan times limit the number of observations that can be made in a given interval of time, imposing restrictions on experimental design and potentially compromising statistical power. Methods that reduce the overall time required to scan multiple cohorts of animals in distinct experimental groups are therefore highly desirable. Multiple-mouse MRI, in which several animals are simultaneously scanned in a common MRI system, has been successfully used to improve study throughput. However, to best utilize the next generation of small-animal MRI systems that will be equipped with an increased number of receive channels, a paradigm shift from the simultaneous scanning of as many animals as possible to the scanning of a more manageable number, at a faster rate, must be considered. This work explores the tradeoffs between the number of animals to scan at once and the number of array elements dedicated to each animal, to maximize throughput in systems with 16 receive channels. An array system consisting of 15 receive and five transmit coils allows acceleration by a combination of multi-animal and parallel imaging techniques. The array system was designed and fabricated for use on a 7.0-T/30-cm Bruker Biospec MRI system, and tested for high-throughput imaging performance in phantoms and live mice. Results indicate that up to a nine-fold throughput improvement of a single sequence is possible compared with an unaccelerated single-animal acquisition. True data throughput of a contrast-enhanced anatomical study is estimated to be improved by just over six-fold.
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Affiliation(s)
- Marc S. Ramirez
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
- Department of Biomedical Engineering, The University of Texas, Austin, Texas
| | - Stephen Y. Lai
- Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - James A. Bankson
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
- Department of Biomedical Engineering, The University of Texas, Austin, Texas
- Please address correspondence to: James A. Bankson, Department of Imaging Physics, Unit 56, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, Phone: (713) 792–4273, Fax: (713) 745–9236,
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Yamaguchi M, Mitsuda M, Ezawa K, Nakagami R, Furuta T, Sekine N, Niitsu M, Fujii H. Artifact-reduced simultaneous MRI of multiple rats with liver cancer using PROPELLER. J Magn Reson Imaging 2012; 38:225-30. [PMID: 23238830 DOI: 10.1002/jmri.23969] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/31/2012] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To explore simultaneous magnetic resonance imaging (MRI) for multiple hepatoma-bearing rats in a single session suppressing motion- and flow-related artifacts to conduct preclinical cancer research efficiently. MATERIALS AND METHODS Our institutional Animal Experimental Committee approved this study. We acquired PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) T2 - and diffusion-weighted images of the liver in one healthy and 11 N1-S1 hepatoma-bearing rats in three sessions using a 3-T clinical scanner and dedicated multiarray coil. We compared tumor volumes on MR images and those on specimens, evaluated apparent diffusion coefficients (ADC) of the tumor, and compared them to previously reported values. RESULTS Each MRI session took 39-50 minutes from anesthesia induction to the end of scans for four rats (10-13 minutes per rat). PROPELLER provided artifact-reduced T2 - and diffusion-weighted images of the rat livers. Tumor volumes on MR images ranged from 0.04-1.81 cm(3) and were highly correlated with those on specimens. The ADC was 1.57 ± 0.37 × 10(-3) mm(2) /s (average ± SD), comparable to previously reported values. CONCLUSION PROPELLER allowed simultaneous acquisition of artifact-reduced T2 - and diffusion-weighted images of multiple hepatoma-bearing rats. This technique can promote high-throughput preclinical MR research for liver cancer.
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Affiliation(s)
- Masayuki Yamaguchi
- Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
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10
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Olson JD, Walb MC, Moore JE, Attia A, Sawyer HL, McBride JE, Wheeler KT, Miller MS, Munley MT. A gated-7T MRI technique for tracking lung tumor development and progression in mice after exposure to low doses of ionizing radiation. Radiat Res 2012; 178:321-7. [PMID: 22950352 DOI: 10.1667/rr2800.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A gated-7T magnetic resonance imaging (MRI) application is described that can accurately and efficiently measure the size of in vivo mouse lung tumors from ∼0.1 mm(3) to >4 mm(3). This MRI approach fills a void in radiation research because the technique can be used to noninvasively measure the growth rate of lung tumors in large numbers of mice that have been irradiated with low doses (<50 mGy) without the additional radiation exposure associated with planar X ray, CT or PET imaging. High quality, high resolution, reproducible images of the mouse thorax were obtained in ∼20 min using: (1) a Bruker 7T micro-MRI scanner equipped with a 60 mm inner diameter gradient insert capable of generating a maximum gradient of 1000 mT/m; (2) a 35 mm inner diameter quadrature radiofrequency volume coil; and (3) an electrocardiogram and respiratory gated Fast Low Angle Shot (FLASH) pulse sequence. The images had an in-plane image resolution of 98 μm and a 0.5 mm slice thickness. Tumor diameter measured by MRI was highly correlated (R(2) = 0.97) with the tumor diameter measured by electronic calipers. Data generated with an initiation/promotion mouse model of lung carcinogenesis and this MRI technique demonstrated that mice exposed to 4 weekly fractions of 10, 30 or 50 mGy of CT radiation had the same lung tumor growth rate as that measured in sham-irradiated mice. In summary, this high-field, double-gated MRI approach is an efficient way of quantitatively tracking lung tumor development and progression after exposure to low doses of ionizing radiation.
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Affiliation(s)
- John D Olson
- Center for Biomolecular Imaging, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
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de Carvalho Alegro M, Valotta Silva A, Yumi Bando S, de Deus Lopes R, Martins de Castro LH, Hungtsu W, Moreira-Filho CA, Amaro E. Texture analysis of high resolution MRI allows discrimination between febrile and afebrile initial precipitating injury in mesial temporal sclerosis. Magn Reson Med 2012; 68:1647-53. [PMID: 22287318 DOI: 10.1002/mrm.24174] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 12/12/2011] [Accepted: 12/29/2011] [Indexed: 01/10/2023]
Abstract
A computational pipeline combining texture analysis and pattern classification algorithms was developed for investigating associations between high-resolution MRI features and histological data. This methodology was tested in the study of dentate gyrus images of sclerotic hippocampi resected from refractory epilepsy patients. Images were acquired using a simple surface coil in a 3.0T MRI scanner. All specimens were subsequently submitted to histological semiquantitative evaluation. The computational pipeline was applied for classifying pixels according to: a) dentate gyrus histological parameters and b) patients' febrile or afebrile initial precipitating insult history. The pipeline results for febrile and afebrile patients achieved 70% classification accuracy, with 78% sensitivity and 80% specificity [area under the reader observer characteristics (ROC) curve: 0.89]. The analysis of the histological data alone was not sufficient to achieve significant power to separate febrile and afebrile groups. Interesting enough, the results from our approach did not show significant correlation with histological parameters (which per se were not enough to classify patient groups). These results showed the potential of adding computational texture analysis together with classification methods for detecting subtle MRI signal differences, a method sufficient to provide good clinical classification. A wide range of applications of this pipeline can also be used in other areas of medical imaging.
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Affiliation(s)
- Maryana de Carvalho Alegro
- Brain Institute/Dep. Radiology-Hospital Israelita Albert Einstein, Integrated Systems Laboratory, Escola Politécnica da Universidade de São Paulo, São Paulo, SP, Brazil
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12
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Abstract
Animal handling and preparation is one of the most critical aspects of in vivo NMR imaging in small animals, and involves a broad spectrum of challenges, any of which could affect data quality and reproducibility. This chapter will outline the most critical considerations in animal handling for in vivo MRI experimentation in rodent models. Highly accurate and reproducible positioning is one of the most important aspects, since sensitivity, motion and susceptibility artifacts, animal imaging throughput, and ease of data quantification are all dependent on it. A variety of devices exist today that assist in several aspects of animal handling and positioning, each with its own advantages and limitations. This chapter will detail many of the devices that are commercially available and how they have dealt with integration of RF coil technology, restraint, anesthesia, fiducial markers, warming, and physiological monitoring. The chapter will additionally detail various aspects of animal anesthesia, maintenance of core body temperature, physiological monitoring, intubation and ventilation, and systemic contrast agent administration. An increasingly important factor in running a small animal MRI laboratory, facility biosecurity, will also be reviewed.
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Affiliation(s)
- Patrick McConville
- Molecular Imaging Research, Inc., 800 Technology Drive, Ann Arbor, MI 48108, USA.
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13
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MITSUDA M, YAMAGUCHI M, FURUTA T, NABETANI A, HIRAYAMA A, NOZAKI A, NIITSU M, FUJII H. Multiple-animal MR Imaging using a 3T Clinical Scanner and Multi-channel Coil for Volumetric Analysis in a Mouse Tumor Model. Magn Reson Med Sci 2011; 10:229-37. [DOI: 10.2463/mrms.10.229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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14
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Gruemmer R, Maderwald S, Winterhager E, Hauth E. Screening for embryonic loss during in utero development of mice with a human 1.5 Tesla clinical MRI scanner. J Magn Reson Imaging 2010; 32:1158-65. [PMID: 21031522 DOI: 10.1002/jmri.22351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To establish in utero MRI-scanning of mouse implantation sites in a 1.5 Tesla whole-body human clinical scanner for evaluation of impaired implantation, placental or developmental defects due to genetic alterations. MATERIALS AND METHODS Pregnant C57Bl/6 wild-type and Cx31-deficient mice revealing placental defects were analyzed in utero using a 1.5 Tesla whole-body clinical scanner in combination with a 3-cm-diameter single loop (slice thickness: 1.2 mm). Imaging of implantation sites was evaluated from 6.5-13.5 dpc and amount of implantation sites and in vivo development was analyzed during the critical phase of placentation from 10.5-13.5 dpc. RESULTS This method provided high resolution in plane images permitting confident identification of all implantation sites from 6.5 dpc onward. A loss of 60% of Cx31-deficient embryos was demonstrated compared with controls. Repeated anesthesia as well as imaging protocols produced no gross malformations in the surviving mice. CONCLUSION Using a human clinical MRI scanner high resolution imaging of the entire uterus of the mice and all the embryos inside could be performed. This method is well suited to noninvasively monitor and quantify embryo implantation and to follow this dynamic process in vivo without compromising pregnancy progression and embryonic development.
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Affiliation(s)
- Ruth Gruemmer
- Institute of Molecular Biology, University Hospital, Essen, Germany.
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15
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Ramirez MS, Esparza-Coss E, Bankson JA. Multiple-mouse MRI with multiple arrays of receive coils. Magn Reson Med 2010; 63:803-10. [PMID: 20146352 DOI: 10.1002/mrm.22236] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Compared to traditional single-animal imaging methods, multiple-mouse MRI has been shown to dramatically improve imaging throughput and reduce the potentially prohibitive cost for instrument access. To date, up to a single radiofrequency coil has been dedicated to each animal being simultaneously scanned, thus limiting the sensitivity, flexibility, and ultimate throughput. The purpose of this study was to investigate the feasibility of multiple-mouse MRI with a phased-array coil dedicated to each animal. A dual-mouse imaging system, consisting of a pair of two-element phased-array coils, was developed and used to achieve acceleration factors greater than the number of animals scanned at once. By simultaneously scanning two mice with a retrospectively gated cardiac cine MRI sequence, a 3-fold acceleration was achieved with signal-to-noise ratio in the heart that is equivalent to that achieved with an unaccelerated scan using a commercial mouse birdcage coil.
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Affiliation(s)
- Marc S Ramirez
- Department of Imaging Physics, The University of Texas M D Anderson Cancer Center, Houston, Texas 77030-4009, USA
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16
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17
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Murine liver implantation of radiation-induced fibrosarcoma: characterization with MR imaging, microangiography and histopathology. Eur Radiol 2008; 18:1422-30. [PMID: 18343928 DOI: 10.1007/s00330-008-0904-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 11/27/2007] [Accepted: 12/30/2007] [Indexed: 02/06/2023]
Abstract
We sought to establish and characterize a mouse liver tumor model as a platform for preclinical assessment of new diagnostics and therapeutics. Radiation-induced fibrosarcoma (RIF-1) was intrahepatically implanted in 27 C3H/Km mice. Serial in vivo magnetic resonance imaging (MRI) with a clinical 1.5-T-magnet was performed using T1- (T1WI), T2- (T2WI), and diffusion-weighted sequences (DWI), dynamic contrast-enhanced MRI (DCE-MRI), and contrast-enhanced T1WI, and validated with postmortem microangiography and histopathology. Implantation procedure succeeded in 25 mice with 2 deaths from overdosed anesthesia or hypothermia. RIF-1 grew in 21 mice with volume doubling time of 2.55+/-0.88 days and final size of 216.2+/-150.4 mm(3) at day 14. Three mice were found without tumor growth and one only with abdominal seeding. The intrahepatic RIF-1 was hypervascularized with negligible necrosis as shown on MRI, microangiography and histology. On DCE-MRI, maximal initial slope of contrast-time curve and volume transfer constant per unit volume of tissue, K, differed between the tumor and liver with only the former significantly lower in the tumor than in the liver (P<0.05). Liver implantation of RIF-1 in mice proves a feasible and reproducible model and appears promising for use to screen new diagnostics and therapeutics under noninvasive monitoring even with a clinical MRI system.
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18
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Sonabend AM, Ulasov IV, Lesniak MS. Emerging role of new transgenic mouse models in glioma research. Expert Rev Anticancer Ther 2008; 7:S7-13. [PMID: 18076321 DOI: 10.1586/14737140.7.12s.s7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Our understanding of glioma biology has relied heavily on the use of cell lines and xenograft animal models. However, the recent development of transgenic mouse models offers a unique opportunity to examine the pathophysiology of these tumors in immunocompetent models in vivo. Transgenic models are highly informative for a number of reasons. First, the resulting tumors are genetically and histologically similar to human gliomas. Second, transgenic models allow the study of causality of genetic/pathway alterations reminiscent of human gliomas. Third, new therapies can be tested in established tumors to truly evaluate their potential efficacy. This review describes the available technologies involved in transgenic and knockout mouse modeling, including the generation of cell-type-specific genetic alterations. Finally, genetics are discussed with a focus on how transgenic murine gliomas recapitulate alterations found in human counterparts.
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Affiliation(s)
- Adam M Sonabend
- The University of Chicago Brain Tumor Center, The University of Chicago Section of Neurosurgery, Chicago, IL, USA.
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19
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Abstract
PURPOSE To investigate practical methods for achieving routine simultaneous 2D MRI of multiple animals in large-bore experimental scanners. MATERIALS AND METHODS Three four-element array geometries were compared against a standard single-coil configuration in terms of image quality, ease of use, and data efficiency using a four-channel, 4.7 T small animal imaging system. RESULTS A linear arrangement of volume resonators permits unobstructed animal preparation and use of an imaging protocol that is almost identical to the single-coil configuration without requiring any image correction or other additional postprocessing. Resulting in vivo images were visually indistinguishable from those acquired through the single-coil configuration. CONCLUSION The efficiency of animal studies employing 2D MRI techniques can be substantially improved by using a linear array of commercially available resonators.
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Affiliation(s)
- Marc S Ramirez
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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20
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Linn J, Schwarz F, Schichor C, Wiesmann M. Cranial MRI of small rodents using a clinical MR scanner. Methods 2007; 43:2-11. [PMID: 17720558 DOI: 10.1016/j.ymeth.2007.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 01/19/2007] [Accepted: 03/27/2007] [Indexed: 11/20/2022] Open
Abstract
Increasing numbers of small animal models are in use in the field of neuroscience research. Magnetic resonance imaging (MRI) provides an excellent method for non-invasive imaging of the brain. Using three-dimensional (3D) MR sequences allows lesion volumetry, e.g. for the quantification of tumor size. Specialized small-bore animal MRI scanners are available for high-resolution MRI of small rodents' brain, but major drawbacks of this dedicated equipment are its high costs and thus its limited availability. Therefore, more and more research groups use clinical MR scanners for imaging small animal models. But to achieve a reasonable spatial resolution at an acceptable signal-to-noise ratio with these scanners, some requirements concerning sequence parameters have to be matched. Thus, the aim of this paper was to present in detail a method how to perform MRI of small rodents brain using a standard clinical 1.5 T scanner and clinically available radio frequency coils to keep material costs low and to circumvent the development of custom-made coils.
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Affiliation(s)
- Jennifer Linn
- Department of Neuroradiology, University Hospital Munich, Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany.
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21
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Ginefri JC, Poirier-Quinot M, Girard O, Darrasse L. Technical aspects: Development, manufacture and installation of a cryo-cooled HTS coil system for high-resolution in-vivo imaging of the mouse at 1.5T. Methods 2007; 43:54-67. [PMID: 17720564 DOI: 10.1016/j.ymeth.2007.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 01/30/2007] [Accepted: 03/27/2007] [Indexed: 11/23/2022] Open
Abstract
Signal-to-noise ratio improvement is of major importance to achieve microscopic spatial resolution in magnetic resonance experiments. Magnetic resonance imaging of small animals is particularly concerned since it typically requires voxels of less than (100 microm)(3) to observe the small anatomical structures having size reduction by a factor of more than 10 as compared to human being. The signal-to-noise ratio can be increased by working at high static magnetic field strengths, but the biomedical interest of such high-field systems may be limited due to field-dependent contrast mechanisms and severe technological difficulties. An alternative approach that allows working in clinical imaging system is to improve the sensitivity of the radio-frequency receiver coil. This can be done using small cryogenically operated coils made either of copper or high-temperature superconducting material. We report the technological development of cryo-cooled superconducting coils for high-resolution imaging in a whole-body magnetic resonance scanner operating at 1.5 T. The technological background supporting this development is first addressed, including HTS coil design, simulation tools, cryogenic mean description and electrical characterization procedure. To illustrate the performances of superconducting coils for magnetic resonance imaging at intermediate field strength, in-vivo mouse images of various anatomic sites acquired with a 12 mm diameter cryo-cooled superconducting coil are presented.
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22
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Brockmann MA, Kemmling A, Groden C. Current issues and perspectives in small rodent magnetic resonance imaging using clinical MRI scanners. Methods 2007; 43:79-87. [PMID: 17720566 DOI: 10.1016/j.ymeth.2007.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 07/10/2007] [Indexed: 12/16/2022] Open
Abstract
Small rodents such as mice and rats are frequently used in animal experiments for several reasons. In the past, animal experiments were frequently associated with invasive methods and groups of animals had to be killed to perform longitudinal studies. Today's modern imaging techniques such as magnetic resonance imaging (MRI) allow non-invasive longitudinal monitoring of multiple parameters. Although only a few institutions have access to dedicated small animal MR scanners, most institutions carrying out animal experiments have access to clinical MR scanners. Technological advances and the increasing field strength of clinical scanners make MRI a broadly available and viable technique in preclinical in vivo research. This review provides an overview of current concepts, limitations, and recent studies dealing with small animal imaging using clinical MR scanners.
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Affiliation(s)
- Marc A Brockmann
- Department of Neuroradiology, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 61867 Mannheim, Germany.
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23
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In vivo MRI volumetric measurement of prostate regression and growth in mice. BMC Urol 2007; 7:12. [PMID: 17650332 PMCID: PMC1945027 DOI: 10.1186/1471-2490-7-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 07/24/2007] [Indexed: 11/10/2022] Open
Abstract
Background Mouse models for treatment of late-stage prostate cancer are valuable tools, but assessing the extent of growth of the prostate and particularly its regression due to therapeutic intervention or castration is difficult due to the location, small size and interdigitated anatomy of the prostate gland in situ. Temporal monitoring of mouse prostate regression requires multiple animals and examination of histological sections.
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24
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Nieman BJ, Bishop J, Dazai J, Bock NA, Lerch JP, Feintuch A, Chen XJ, Sled JG, Henkelman RM. MR technology for biological studies in mice. NMR IN BIOMEDICINE 2007; 20:291-303. [PMID: 17451169 DOI: 10.1002/nbm.1142] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Mouse models are crucial for the study of genetic factors and processes that influence human disease. In addition to tools for measuring genetic expression and establishing genotype, tools to accurately and comparatively assess mouse phenotype are essential in order to characterize pathology and make comparisons with human disease. MRI provides a powerful means of evaluating various anatomical and functional changes and hence is growing in popularity as a phenotypic readout for biomedical research studies. To accommodate the large numbers of mice needed in most biological studies, mouse MRI must offer high-throughput image acquisition and efficient image analysis. This article reviews the technology of multiple-mouse MRI, a method that images multiple mice or specimens simultaneously as a means of enabling high-throughput studies. Aspects of image acquisition and computational analysis in multiple-mouse studies are also described.
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Affiliation(s)
- Brian J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada
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25
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Jost SC, Wanebo JE, Song SK, Chicoine MR, Rich KM, Woolsey TA, Lewis JS, Mach RH, Xu J, Garbow JR. In vivo imaging in a murine model of glioblastoma. Neurosurgery 2007; 60:360-70; discussion 370-1. [PMID: 17290188 DOI: 10.1227/01.neu.0000249264.80579.37] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To use in vivo imaging methods in mice to quantify intracranial glioma growth, to correlate images and histopathological findings, to explore tumor marker specificity, to assess effects on cortical function, and to monitor effects of chemotherapy. METHODS Mice with DBT glioma cell tumors implanted intracranially were imaged serially with a 4.7-T small-animal magnetic resonance imaging (MRI) scanner. MRI tumor volumes were measured and correlated with postmortem histological findings. Different nonspecific and specific positron emission tomography radiopharmaceuticals, [18F]2-fluoro-2-deoxy-d-glucose, [18F]3'-deoxy-3'-fluorothymidine, or [11C]RHM-I, a sigma2-receptor ligand, were visualized with microPET (CTI-Concorde MicroSystems LLC, Knoxville, TN). Intrinsic optical signals were imaged serially during contralateral whisker stimulation to study the impact of tumor growth on cortical function. Other groups of mice were imaged serially with MRI after one or two doses of the antimitotic N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU). RESULTS MRI and histological tumor volumes were highly correlated (r2 = 0.85). Significant binding of [11C]RHM-I was observed in growing tumors. Over time, tumors reduced and displaced (P # 0.001) whisker-activated intrinsic optical signals but did not change intrinsic optical signals in the contralateral hemisphere. Tumor growth was delayed 7 days after a single dose of BCNU and 18 days after two doses of BCNU. Mean tumor volume 15 days after DBT implantation was significantly smaller for treated mice (1- and 2-dose BCNU) compared with controls (P = 0.0026). CONCLUSION Mouse MRI, positron emission tomography, and optical imaging provide quantitative and qualitative in vivo assessments of intracranial tumors that correlate directly with tumor histological findings. The combined imaging approach provides powerful multimodality assessments of tumor progression, effects on brain function, and responses to therapy.
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Affiliation(s)
- Sarah C Jost
- Department of Neurosurgery, Washington University, School of Medicine, St. Louis, Missouri 63110, USA
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26
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Beuf O, Jaillon F, Saint-Jalmes H. Small-animal MRI: signal-to-noise ratio comparison at 7 and 1.5 T with multiple-animal acquisition strategies. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2006; 19:202-8. [PMID: 16957937 DOI: 10.1007/s10334-006-0048-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The purpose of this study was to compare the signal-to-noise ratio (SNR) of phantom and rat brain images performed at 1.5 T on a clinical MR system and at 7 T on a small-animal experimental system. Comparison was carried out by taking into account SNR values based on a single sample acquisition at 1.5 and 7 T as well as on simultaneous imaging of multiple samples at 1.5 T. METHODS SNR was experimentally assessed on a phantom and rat brains at 1.5 and 7 T using 25 mm surface coils and compared to theoretical SNR gain estimations. The feasibility of multiple-animal imaging, using the hardware capabilities available on the 1.5 T system, was demonstrated. Finally, rat brain images obtained on a single animal at 7 T and on multiple animals acquired simultaneously at 1.5 T were compared. RESULTS Experimentally determined SNR at 7 T was far below theoretical estimations. Taking into account chemical shift, susceptibility artifacts and modifications of T1 and T2 relaxation times at higher field, a 7-T system holds limited advantage over a 1.5-T system. Instead, a multiple-animal acquisition methodology was demonstrated on a clinical 1.5-T scanner. This acquisition method significantly increases imaging efficiency and competes with single animal acquisitions at higher field. CONCLUSION Multiple-animal imaging using a standard clinical scanner has a great potential as a high-throughput acquisition method for small animals.
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Affiliation(s)
- Olivier Beuf
- Laboratoire de RMN, CNRS UMR 5012, Université Lyon1, ESCPE, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne, France.
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27
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Rosen Y, Ramniceanu G, Margalit R, Grobgeld D, Eilam R, Degani H, Furman-Haran E. Vascular perfusion of human lung cancer in a rat orthotopic model using dynamic contrast-enhanced magnetic resonance imaging. Int J Cancer 2006; 119:365-72. [PMID: 16470842 DOI: 10.1002/ijc.21857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Lung cancer is the leading cause of death among cancers. Early detection and diagnosis present a major goal in the efforts to improve survival rates of lung cancer patients. Changes in angiogenic activity and microvascular perfusion properties in cancers can serve as markers of malignancy. The aim of this study was to employ MRI means to measure the microvascular perfusion parameters of orthotopic nonsmall cell lung cancer, using the experimental rat model. Anatomical and dynamic contrast-enhanced lung images were acquired at high spatial resolution, and registered and analyzed, pixel by pixel and globally, by means of a model-based algorithm. The MRI output yielded color-coded parametric images of the influx and efflux transcapillary transfer constants that indicated rapid microvascular perfusion. The transfer constants were about 1 order of magnitude higher than those found in other tumors or in nonorthotopic lung cancer, with the influx constant median value of 0.42 min(-1) and the efflux constant median value of 1.61 min(-1). The rapid perfusion was in accord with the immunostaining of the capillaries, which suggested the tumor exploitation of the existing alveolar vessels. The results showed that high resolution, dynamic, contrast-enhanced MRI is an effective tool for the quantitative measurement of spatial and temporal changes in lung cancer perfusion and vasculature.
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Affiliation(s)
- Yael Rosen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
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28
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Fricke ST, Rodriguez O, Vanmeter J, Dettin LE, Casimiro M, Chien CD, Newell T, Johnson K, Ileva L, Ojeifo J, Johnson MD, Albanese C. In vivo magnetic resonance volumetric and spectroscopic analysis of mouse prostate cancer models. Prostate 2006; 66:708-17. [PMID: 16425198 DOI: 10.1002/pros.20392] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Mouse prostate cancer modeling presents unique obstacles to the study of spontaneous tumor initiation and progression due to the anatomical location of the tissue. RESULTS High resolution (130 microm(x) x 130 microm(y) x 300 microm(z)), three-dimensional MRI allowed for the visualization, segmentation, and volumetric measurement of the prostate from normal and genetically engineered animals, in vivo. Additionally, MRS performed on the prostate epithelia of probasin-ErbB-2Delta x Pten(+/-) mice identified changes in the relative concentrations of the metabolites choline and citrate, which was not observed in TRAMP mice. METHODS T1-weighted MRI was performed on normal, TRAMP, probasin-ErbB-2/Her2/Neu (probasin-ErbB-2Delta), and probasin-ErbB-2Delta in the context of decreased Pten activity (probasin-ErbB-2Delta x Pten(+/-)) mice. Volume-localized single-voxel proton magnetic resonance spectroscopy (SVS (1)H MRS) was also performed. CONCLUSIONS The data presented supports the use of combined MRI and MRS for the measurement of biochemical and morphometric alterations in mouse models of prostate cancer.
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Affiliation(s)
- Stanley T Fricke
- Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
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29
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Abstract
We developed a live high-field multiple-mouse magnetic resonance imaging method to increase the throughput of imaging studies involving large numbers of mice. Phantom experiments were performed in 7 shielded radiofrequency (RF) coils for concurrent imaging on a 7 Tesla MRI scanner outfitted with multiple transmit and receive channels to confirm uniform signal-to-noise ratio and minimal ghost artifacts across images from the different RF coils. Grid phantoms were used to measure image distortion in different positions in the coils. The brains of 7 live mice were imaged in 3D in the RF coil array, and a second array of 16 RF coils was used to 3D image the whole bodies of 16 fixed, contrast agent-perfused mice. The images of the 7 live mouse brains at 156 microm isotropic resolution and the 16 whole fixed mice at 100 microm isotropic resolution were of high quality and free of artifacts. We have thus shown that multiple-mouse MRI increases throughput for live and fixed mouse experiments by a factor equaling the number of RF coils in the scanner.
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Affiliation(s)
- Nicholas A Bock
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.
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30
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Brockmann MA, Ulmer S, Leppert J, Nadrowitz R, Wuestenberg R, Nolte I, Petersen D, Groden C, Giese A, Gottschalk S. Analysis of mouse brain using a clinical 1.5 T scanner and a standard small loop surface coil. Brain Res 2006; 1068:138-42. [PMID: 16380102 DOI: 10.1016/j.brainres.2005.10.098] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 10/19/2005] [Accepted: 10/26/2005] [Indexed: 11/18/2022]
Abstract
With increasing numbers of in vivo experiments in the field of neuroscience, the interest in methods for in vivo imaging of animal brains as small as those of mice has increased. Because highly specialized small bore scanners with high field strengths are not commonly available, clinical magnetic resonance imaging (cMRI) scanners have been used in the past to image rat and more recently also mouse brains in combination with specifically developed RF coils. These studies have demonstrated that imaging of small animal brains is feasible, and that tumor volumes measured by cMRI correlate well with histological tumor volume analysis. This protocol describes the cMRI settings at 1.5 T for imaging of mouse brain with resolutions up to 120 x 120 microm using an inexpensive, commercially available small loop surface coil. This allows easy establishment of a small animal MRI facility without the need for cost intensive dedicated small animal scanners or special custom made coils. In this study, we demonstrate high-resolution imaging of intracranial xenografts in a mouse glioma model and monitor the treatment effect of external field irradiation by cMRI.
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Affiliation(s)
- M-A Brockmann
- Department of Neuroradiology, Faculty for Clinical Medicine Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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Nieman BJ, Bock NA, Bishop J, Chen XJ, Sled JG, Rossant J, Henkelman RM. Magnetic resonance imaging for detection and analysis of mouse phenotypes. NMR IN BIOMEDICINE 2005; 18:447-68. [PMID: 16206127 DOI: 10.1002/nbm.981] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
With the enormous and growing number of experimental and genetic mouse models of human disease, there is a need for efficient means of characterizing abnormalities in mouse anatomy and physiology. Adaptation of magnetic resonance imaging (MRI) to the scale of the mouse promises to address this challenge and make major contributions to biomedical research by non-invasive assessment in the mouse. MRI is already emerging as an enabling technology providing informative and meaningful measures in a range of mouse models. In this review, recent progress in both in vivo and post mortem imaging is reported. Challenges unique to mouse MRI are also identified. In particular, the needs for high-throughput imaging and comparative anatomical analyses in large biological studies are described and current efforts at handling these issues are presented.
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Affiliation(s)
- Brian J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada.
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McConville P, Moody JB, Moffat BA. High-throughput magnetic resonance imaging in mice for phenotyping and therapeutic evaluation. Curr Opin Chem Biol 2005; 9:413-20. [PMID: 16002325 DOI: 10.1016/j.cbpa.2005.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 06/21/2005] [Indexed: 01/04/2023]
Abstract
High-throughput mouse magnetic resonance imaging (MRI) is seeing rapidly increasing demand in development of therapeutics. Recent advances including higher-field systems, new gradient and radio frequency coils and new pulse sequences, coupled with efficient animal preparation and data handling, allow high-throughput MRI under certain protocols. However, with current shifts from anatomic to functional and molecular imaging, innovative technology is required to meet new throughput demands. The first multiple mouse imaging strategies have provided a glimpse of the future state-of-the-art. However, the successful translation of standard clinical MRI technology to preclinical MRI is required to facilitate next-generation high-throughput MRI.
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Ginefri JC, Poirier-Quinot M, Robert P, Darrasse L. Contrast-enhanced dynamic MRI protocol with improved spatial and time resolution for in vivo microimaging of the mouse with a 1.5-T body scanner and a superconducting surface coil. Magn Reson Imaging 2005; 23:239-43. [PMID: 15833619 DOI: 10.1016/j.mri.2004.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Accepted: 11/12/2004] [Indexed: 11/26/2022]
Abstract
Magnetic resonance imaging (MRI) is well suited for small animal model investigations to study various human pathologies. However, the assessment of microscopic information requires a high-spatial resolution (HSR) leading to a critical problem of signal-to-noise ratio limitations in standard whole-body imager. As contrast mechanisms are field dependent, working at high field do not allow to derive MRI criteria that may apply to clinical settings done in standard whole-body systems. In this work, a contrast-enhanced dynamic MRI protocol with improved spatial and time resolution was used to perform in vivo tumor model imaging on the mouse at 1.5 T. The needed sensitivity is provided by the use of a 12-mm superconducting surface coil operating at 77 K. High quality in vivo images were obtained and revealed well-defined internal structures of the tumor. A 3-D HSR sequence with voxels of 59x59x300 microm3 encoded within 6.9 min and a 2-D sequence with subsecond acquisition time and isotropic in-plane resolution of 234 microm were used to analyze the contrast enhancement kinetics in tumoral structures at long and short time scales. This work is a first step to better characterize and differentiate the dynamic behavior of tumoral heterogeneities.
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Affiliation(s)
- Jean-Christophe Ginefri
- Unité de Recherche en Résonance Magnétique Médicale, CNRS, UMR 8081, Bâtiment 220, Université Paris XI, 91405 Orsay, France.
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Lazovic J, Stojkovic DS, Collins CM, Yang QX, Vaughan JT, Smith MB. Hexagonal zero mode TEM coil: A single-channel coil design for imaging multiple small animals. Magn Reson Med 2005; 53:1150-7. [PMID: 15844165 DOI: 10.1002/mrm.20459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel hexagonal coil design for simultaneous imaging of multiple small animals is presented. The design is based on a coaxial cavity and utilizes the magnetic field formed between two coaxial conductors with hexagonal cross-sections. An analytical solution describing the B(1) field between conductors of the hexagonal coil was found from the Biot-Savart law. Both experimental results and analytical calculations showed a variation in the B(1) field within the imaging region of less than 10%. Numerical calculations predicted approximately 35% improvement in B(1) field homogeneity with the hexagonal coil design compared to a cylindrical coaxial cavity design. The experimentally-measured signal-to-noise ratio (SNR) of the hexagonal coil loaded with six 50-mM phantoms was only 4-5% lower than that of a single parallel plate resonator loaded with one phantom. In vivo spin-echo (SE) images of six 7-day-old rat pups acquired simultaneously demonstrated sufficient SNR for microimaging. The construction scheme of the coil, simple methods for tuning and matching, and an anesthesia device and animal holder designed for the coil are described. The hexagonal coil design utilizes a single receiver and allows for simultaneous imaging of six small animals with no significant compromise in SNR.
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Affiliation(s)
- Jelena Lazovic
- Center for NMR Research, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, 17033, USA
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Henkelman RM, Chen XJ, Sled JG. Disease phenotyping: structural and functional readouts. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2005; 62:151-84. [PMID: 16329257 DOI: 10.1007/3-7643-7426-8_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- R Mark Henkelman
- Mouse Imaging Centre (MICe), Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario, Canada MSG 1X8.
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Shih AH, Dai C, Hu X, Rosenblum MK, Koutcher JA, Holland EC. Dose-Dependent Effects of Platelet-Derived Growth Factor-B on Glial Tumorigenesis. Cancer Res 2004; 64:4783-9. [PMID: 15256447 DOI: 10.1158/0008-5472.can-03-3831] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelet-derived growth factor (PDGF) is expressed in many different tumors, but its precise roles in tumorigenesis remain to be fully defined. Here, we report on a mouse model that demonstrates dose-dependent effects of PDGF-B on glial tumorigenesis. By removing inhibitory regulatory elements in the PDGFB mRNA, we are able to substantially elevate its expression in tumor cells using a retroviral delivery system. This elevation in PDGF-B production results in tumors with shortened latency, increased cellularity, regions of necrosis, and general high-grade character. In addition, elevated PDGF-B in these tumors also mediates vascular smooth muscle cell recruitment that supports tumor angiogenesis. PDGF receptor (PDGFR) signaling appears to be required for the maintenance of these high-grade characteristics, because treatment of high-grade tumors with a small molecule inhibitor of PDGFR results in reversion to a lower grade tumor histology. Our data show that PDGFR signaling quantitatively regulates tumor grade and is required to sustain high-grade oligodendrogliomas.
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Affiliation(s)
- Alan H Shih
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
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Bock NA, Zadeh G, Davidson LM, Qian B, Sled JG, Guha A, Henkelman RM. High-resolution longitudinal screening with magnetic resonance imaging in a murine brain cancer model. Neoplasia 2004; 5:546-54. [PMID: 14965447 PMCID: PMC1502570 DOI: 10.1016/s1476-5586(03)80038-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
One of the main limitations of intracranial models of diseases is our present inability to monitor and evaluate the intracranial compartment noninvasively over time. Therefore, there is a growing need for imaging modalities that provide thorough neuropathological evaluations of xenograft and transgenic models of intracranial pathology. In this study, we have established protocols for multiple-mouse magnetic resonance imaging (MRI) to follow the growth and behavior of intracranial xenografts of gliomas longitudinally. We successfully obtained weekly images on 16 mice for a total of 5 weeks on a 7-T multiple-mouse MRI. T2- and T1-weighted imaging with gadolinium enhancement of vascularity was used to detect tumor margins, tumor size, and growth. These experiments, using 3D whole brain images obtained in four mice at once, demonstrate the feasibility of obtaining repeat radiological images in intracranial tumor models and suggest that MRI should be incorporated as a research modality for the investigation of intracranial pathobiology.
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Affiliation(s)
- Nicholas A Bock
- Department of Medical Biophysics, University of Toronto, Toronto, Canada.
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Brockmann MA, Ulmer S, Lamszus K, Giese A, Petersen D. Technical note: A toy as tool: a low-cost image analysis system for the evaluation of tumor size in experimental small animal models. Microsc Res Tech 2004; 63:306-9. [PMID: 15170761 DOI: 10.1002/jemt.20035] [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: 11/11/2022]
Abstract
Image analysis systems are an essential tool in measurements of size of intraparenchymal tumors or lesions in experimental small animal models. Conventional image analysis systems are relatively expensive. We therefore compared the performance of a professional image analysis system with an inexpensive setup by evaluating tumor size in an orthotopic glioma mouse model. The maximum cross-sectional tumor area of H&E stained brain-slides of two groups of mice (treatment and control group) was measured by two independent investigators using a professional image analysis system (Leica DM IRB microscope) with the Leica Quantimet 500c software, and a low-cost-system (Intel QX3 microscope) with a non-commercial image analysis software. Mean tumor volumes were calculated and the results from each of the image analysis systems, investigators, and treatment effects were compared. The tumor volumes as measured with the low-cost and the professional system differed between -3.7 and +7.5% (P = 0.69-0.99). Measurements made by investigator A and B differed between -7.0 and +3.9% (P = 0.69-0.88). Treatment in all cases significantly reduced the tumor volume between 58.4 and 62.7% (P = 0.0002 or 0.0003), regardless of the investigator or the used image analysis system. We therefore conclude that the QX3 low-cost microscope in combination with a non-commercial image-analysis software represents an inexpensive solution to reliably analyze the size of regions of interest, if they provide a sufficient contrast. However, the low-cost setup due to its low resolution definitely limits a detailed analysis of histologic features.
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Affiliation(s)
- Marc Alexander Brockmann
- Department of Neuroradiology, University Hospital Schleswig-Holstein, Campus Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany.
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Dazai J, Bock NA, Nieman BJ, Davidson LM, Henkelman RM, Chen XJ. Multiple mouse biological loading and monitoring system for MRI. Magn Reson Med 2004; 52:709-15. [PMID: 15389955 DOI: 10.1002/mrm.20215] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The use of mice to study models of human disease has resulted in a surge of interest in developing mouse MRI. The ability to take 3D, high-resolution images of live mice allows significant insight into anatomy and function. However, with imaging times on the order of hours, high throughput of specimens has been problematic. To facilitate high throughput, concurrent imaging of multiple mice has been developed; however, this poses further complexities regarding the ease and rapidity of loading several animals. In this study, custom-built equipment was developed to streamline the preparation process and to safely maintain seven mice during a multiple-mouse imaging session. Total preparation time for seven mice was approximately 24 min. ECG and temperature were monitored throughout the scan and maintained by regulating anesthetic and heating. Proof of principle was demonstrated in a 3-h imaging session of seven mice.
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Affiliation(s)
- Jun Dazai
- Mouse Imaging Centre, Developmental Biology, The Hospital for Sick Children, Toronto, Canada
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