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Kleynhans J, Sathekge MM, Ebenhan T. Preclinical Research Highlighting Contemporary Targeting Mechanisms of Radiolabelled Compounds for PET Based Infection Imaging. Semin Nucl Med 2023; 53:630-643. [PMID: 37012169 DOI: 10.1053/j.semnuclmed.2023.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 04/04/2023]
Abstract
It is important to constantly monitor developments in the preclinical imaging arena of infection. Firstly, novel radiopharmaceuticals with the correct characteristics must be identified to funnel into the clinic. Secondly, it must be evaluated if enough innovative research is being done and adequate resources are geared towards the development of radiopharmaceuticals that could feed into the Nuclear Medicine Clinic in the near future. It is proposed that the ideal infection imaging agent will involve PET combined with CT but more ideally MRI. The radiopharmaceuticals currently presented in preclinical literature have a wide selection of vectors and targets. Ionic formulations of PET-radionuclides such 64CuCl2 and 68GaCl2 are evaluated for bacterial infection imaging. Many small molecule based radiopharmaceuticals are being investigated with the most prominent targets being cell wall synthesis, maltodextrin transport (such as [18F]F-maltotriose), siderophores (bacterial and fungal infections), the folate synthesis pathway (such as [18F]F-PABA) and protein synthesis (radiolabelled puromycin). Mycobacterial specific antibiotics, antifungals and antiviral agents are also under investigation as infection imaging agents. Peptide based radiopharmaceuticals are developed for bacterial, fungal and viral infections. The radiopharmaceutical development could even react quickly enough on a pandemic to develop a SARS-CoV-2 imaging agent in a timely fashion ([64Cu]Cu-NOTA-EK1). New immuno-PET agents for the imaging of viruses have recently been published, specifically for HIV persistence but also for SARS-CoV2. A very promising antifungal immuno-PET agent (hJ5F) is also considered. Future technologies could include the application of aptamers and bacteriophages and even going as far as the design of theranostic infection. Another possibility would be the application of nanobodies for immuno-PET applications. Standardization and optimization of the preclinical evaluation of radiopharmaceuticals could enhance clinical translation and reduce time spent in pursuing less than optimal candidates.
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Affiliation(s)
- Janke Kleynhans
- Department of Pharmaceutical and Pharmacological sciences, Radiopharmaceutical Research, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Mike Machaba Sathekge
- Department of Nuclear Medicine, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa; Preclinical Imaging Facility, Nuclear Medicine Research Infrastructure, Pretoria, South Africa
| | - Thomas Ebenhan
- Preclinical Imaging Facility, Nuclear Medicine Research Infrastructure, Pretoria, South Africa; Department of Nuclear Medicine, University of Pretoria, Pretoria, South Africa.
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2
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Schwenck J, Sonanini D, Cotton JM, Rammensee HG, la Fougère C, Zender L, Pichler BJ. Advances in PET imaging of cancer. Nat Rev Cancer 2023:10.1038/s41568-023-00576-4. [PMID: 37258875 DOI: 10.1038/s41568-023-00576-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/17/2023] [Indexed: 06/02/2023]
Abstract
Molecular imaging has experienced enormous advancements in the areas of imaging technology, imaging probe and contrast development, and data quality, as well as machine learning-based data analysis. Positron emission tomography (PET) and its combination with computed tomography (CT) or magnetic resonance imaging (MRI) as a multimodality PET-CT or PET-MRI system offer a wealth of molecular, functional and morphological data with a single patient scan. Despite the recent technical advances and the availability of dozens of disease-specific contrast and imaging probes, only a few parameters, such as tumour size or the mean tracer uptake, are used for the evaluation of images in clinical practice. Multiparametric in vivo imaging data not only are highly quantitative but also can provide invaluable information about pathophysiology, receptor expression, metabolism, or morphological and functional features of tumours, such as pH, oxygenation or tissue density, as well as pharmacodynamic properties of drugs, to measure drug response with a contrast agent. It can further quantitatively map and spatially resolve the intertumoural and intratumoural heterogeneity, providing insights into tumour vulnerabilities for target-specific therapeutic interventions. Failure to exploit and integrate the full potential of such powerful imaging data may lead to a lost opportunity in which patients do not receive the best possible care. With the desire to implement personalized medicine in the cancer clinic, the full comprehensive diagnostic power of multiplexed imaging should be utilized.
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Affiliation(s)
- Johannes Schwenck
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen, Germany
- Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany
| | - Dominik Sonanini
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen, Germany
- Medical Oncology and Pulmonology, Department of Internal Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Jonathan M Cotton
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany
| | - Hans-Georg Rammensee
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany
- Department of Immunology, IFIZ Institute for Cell Biology, Eberhard Karls University of Tübingen, Tübingen, Germany
- German Cancer Research Center, German Cancer Consortium DKTK, Partner Site Tübingen, Tübingen, Germany
| | - Christian la Fougère
- Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany
- German Cancer Research Center, German Cancer Consortium DKTK, Partner Site Tübingen, Tübingen, Germany
| | - Lars Zender
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany
- Medical Oncology and Pulmonology, Department of Internal Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
- German Cancer Research Center, German Cancer Consortium DKTK, Partner Site Tübingen, Tübingen, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen, Germany.
- Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumour Therapies', Eberhard Karls University, Tübingen, Germany.
- German Cancer Research Center, German Cancer Consortium DKTK, Partner Site Tübingen, Tübingen, Germany.
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3
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Emvalomenos G, Trajanovska S, Pham BTT, Doughty P, Burnet J, Smith I, Garipov R, Gregoire MC, Sunn N, McGrath J, Meikle SR. Performance evaluation of a PET insert for preclinical MRI in stand-alone PET and simultaneous PET-MRI modes. EJNMMI Phys 2021; 8:68. [PMID: 34626239 PMCID: PMC8502182 DOI: 10.1186/s40658-021-00415-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/20/2021] [Indexed: 11/10/2022] Open
Abstract
Background This study aimed to evaluate the performance of a preclinical PET insert in three configurations: as a stand-alone unit outside the MRI bore, inside the bore of a cryogen-free 3T MRI and, finally, while performing simultaneous PET/MRI studies. Methods The PET insert consists of two rings of six detectors, each detector comprising 8 × 12 SiPMs reading out dual offset layers of pixelated LYSO crystals with a 1.4-mm pitch. The inner diameter is 60 mm, transaxial field of view (FoV) 40 mm and axial FoV 98 mm. Evaluation was based on NEMA NU 4-2008 guidelines with appropriate modifications. Spatial resolution and sensitivity were measured inside and outside the MR bore. Image quality, count rate and quantitative performance were measured in all three configurations. The effect of temperature stability on PET sensitivity during fast spin echo sequences was also evaluated. B0 field homogeneity and T1 and T2 relaxation times were measured using a water-filled phantom, with and without simultaneous PET operation. Finally, PET and MRI scans of a mouse injected with 10 MBq [18F]NaF and a mouse injected with 16 MBq [18F]FDG were performed in sequential and simultaneous modes. Results Peak absolute sensitivity was 10.15% with an energy window of 250–750 keV. Absolute sensitivity values outside and inside the MR bore with MR idle agreed to within 0.1%. Outside the MR bore, spatial resolution was 1.21/1.59 mm FWHM (radial/tangential) 5 mm from the centre of the FoV which compared well with 1.19/1.26 mm FWHM inside the MR bore. There were no substantial differences between all three scan configurations in terms of peak NEC rate (175 kcps at 17 MBq), scatter or random fractions. Uniformity and recovery coefficients were also consistent between scanning modes. B0 field homogeneity and T1 and T2 relaxation times were unaltered by the presence of the PET insert. No significant differences were observed between sequential and simultaneous scans of the animals. Conclusions We conclude that the performance of the PET insert and MRI system is not significantly affected by the scanning mode.
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Affiliation(s)
- Gaelle Emvalomenos
- Sydney School of Health Sciences, The University of Sydney, Camperdown, NSW, 2050, Australia. .,Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia.
| | - Sofie Trajanovska
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Binh T T Pham
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | | | - Isabelle Smith
- School of Physics, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | - Marie-Claude Gregoire
- Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia.,Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia
| | - Nana Sunn
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | - Steven R Meikle
- Sydney School of Health Sciences, The University of Sydney, Camperdown, NSW, 2050, Australia.,Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia
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Carvalho RFS, Pereira GAL, Rocha J, Castro MMCA, Granadeiro CM, Nogueira HIS, Peters JA, Geraldes CFGC. Lanthanopolyoxometalate‐Silica Core/Shell Nanoparticles as Potential MRI Contrast Agents. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rui F. S. Carvalho
- Department of Life Sciences Faculty of Science and Technology University of Coimbra Calçada Martim de Freitas 3000-393 Coimbra Portugal
| | - Giovannia A. L. Pereira
- Department of Life Sciences Faculty of Science and Technology University of Coimbra Calçada Martim de Freitas 3000-393 Coimbra Portugal
- CICECO Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
- Fundamental Chemistry Department UFPE Recife, Pernambuco Brazil
| | - João Rocha
- CICECO Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - M. Margarida C. A. Castro
- Department of Life Sciences Faculty of Science and Technology University of Coimbra Calçada Martim de Freitas 3000-393 Coimbra Portugal
- Coimbra Chemistry Center Rua Larga University of Coimbra 3004-535 Coimbra Portugal
| | - Carlos M. Granadeiro
- CICECO Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
- LAQV-REQUIMTE Department of Chemistry and Biochemistry Faculty of Sciences University of Porto Rua do Campo Alegre 4169-007 Porto Portugal
| | - Helena I. S. Nogueira
- CICECO Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - Joop A. Peters
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft The Netherlands
| | - Carlos F. G. C. Geraldes
- Department of Life Sciences Faculty of Science and Technology University of Coimbra Calçada Martim de Freitas 3000-393 Coimbra Portugal
- Coimbra Chemistry Center Rua Larga University of Coimbra 3004-535 Coimbra Portugal
- CIBIT/ICNAS–Instituto de Ciências Nucleares Aplicadas à Saúde Pólo das Ciências da Saúde Azinhaga de Santa Comba 3000-548 Coimbra Portugal
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Abstract
Positron emission tomography (PET) is a non-invasive imaging technology employed to describe metabolic, physiological, and biochemical processes in vivo. These include receptor availability, metabolic changes, neurotransmitter release, and alterations of gene expression in the brain. Since the introduction of dedicated small-animal PET systems along with the development of many novel PET imaging probes, the number of PET studies using rats and mice in basic biomedical research tremendously increased over the last decade. This article reviews challenges and advances of quantitative rodent brain imaging to make the readers aware of its physical limitations, as well as to inspire them for its potential applications in preclinical research. In the first section, we briefly discuss the limitations of small-animal PET systems in terms of spatial resolution and sensitivity and point to possible improvements in detector development. In addition, different acquisition and post-processing methods used in rodent PET studies are summarized. We further discuss factors influencing the test-retest variability in small-animal PET studies, e.g., different receptor quantification methodologies which have been mainly translated from human to rodent receptor studies to determine the binding potential and changes of receptor availability and radioligand affinity. We further review different kinetic modeling approaches to obtain quantitative binding data in rodents and PET studies focusing on the quantification of endogenous neurotransmitter release using pharmacological interventions. While several studies have focused on the dopamine system due to the availability of several PET tracers which are sensitive to dopamine release, other neurotransmitter systems have become more and more into focus and are described in this review, as well. We further provide an overview of latest genome engineering technologies, including the CRISPR/Cas9 and DREADD systems that may advance our understanding of brain disorders and function and how imaging has been successfully applied to animal models of human brain disorders. Finally, we review the strengths and opportunities of simultaneous PET/magnetic resonance imaging systems to study drug-receptor interactions and challenges for the translation of PET results from bench to bedside.
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6
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Jeong WY, Kang MS, Lee H, Lee JH, Kim J, Han DW, Kim KS. Recent Trends in Photoacoustic Imaging Techniques for 2D Nanomaterial-Based Phototherapy. Biomedicines 2021; 9:80. [PMID: 33467616 PMCID: PMC7830416 DOI: 10.3390/biomedicines9010080] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
A variety of 2D materials have been developed for therapeutic biomedical studies. Because of their excellent physicochemical properties, 2D materials can be used as carriers for delivering therapeutic agents into a lesion, leading to phototherapy. Various optical imaging techniques have been used for the monitoring of the treatment process. Among these, photoacoustic imaging has unique advantages including relatively deep imaging depth and large field of view with high spatial resolution. In this review article, we summarize the types of photoacoustic imaging systems used for phototherapy monitoring, then we explore contrast-enhanced photoacoustic images using 2D materials. Finally, photoacoustic image-guided phototherapies are discussed. We conclude that 2D material-based phototherapy can be efficiently monitored by photoacoustic imaging techniques.
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Affiliation(s)
- Woo Yeup Jeong
- School of Chemical Engineering, College of Engineering, Pusan National University, Busan 46241, Korea;
| | - Moon Sung Kang
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea; (M.S.K.); (H.L.)
| | - Haeni Lee
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea; (M.S.K.); (H.L.)
| | - Jong Hun Lee
- Department of Food Science and Biotechnology, Gachon University, Seongnam, Gyeonggi 13120, Korea;
| | - Jeesu Kim
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea; (M.S.K.); (H.L.)
| | - Dong-Wook Han
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea; (M.S.K.); (H.L.)
| | - Ki Su Kim
- School of Chemical Engineering, College of Engineering, Pusan National University, Busan 46241, Korea;
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7
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Torrado-Carvajal A. Importance of attenuation correction in PET/MR image quantification: Methods and applications. Rev Esp Med Nucl Imagen Mol 2020. [DOI: 10.1016/j.remnie.2020.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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8
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Torrado-Carvajal A. Importance of attenuation correction in PET/MR image quantification: Methods and applications. Rev Esp Med Nucl Imagen Mol 2020; 39:163-168. [PMID: 32345573 DOI: 10.1016/j.remn.2020.03.004] [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: 02/24/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 10/24/2022]
Abstract
The generation of accurate attenuation correction (AC) maps is a basic step to allow for quantitative PET/MR imaging. However, generating MR-based AC maps is a challenge because there is no direct relationship between the PET attenuation coefficients (μ) and the intensity of the MR signal, contrary to what happens with the intensity of CT images. In fact, ignoring the bone causes a distorted and biased distribution of the calculated SUV values. To solve this problem, several MR-based AC methods have been proposed in the literature. In this paper we describe how these methods work, and the challenge they faced to translate into full body applications. Currently, in research environments, the accuracy of AC methods is no longer a limiting factor to solve in order to carry out quantitative in vivo molecular imaging studies. However, many of these methods present a series of limitations for their real implementation in the clinical practice due to insufficient clinical validation and the difficulty of their implementation in a real environment (as described in the examples of clinical applications). Thus, we need the PET/MR community to work on the standardization of the use and assessment of different AC methods. In this scenario, the opening and access by vendors to the implementation of new AC methods in their PET/MR scanners plays a crucial role.
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Affiliation(s)
- A Torrado-Carvajal
- Laboratorio de Análisis de Imagen Médica y Biometría, Universidad Rey Juan Carlos, Madrid, España; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, Estados Unidos.
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9
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Yaligar J, Verma SK, Gopalan V, Anantharaj R, Thu Le GT, Kaur K, Mallilankaraman K, Leow MKS, Velan SS. Dynamic contrast-enhanced MRI of brown and beige adipose tissues. Magn Reson Med 2019; 84:384-395. [PMID: 31799761 DOI: 10.1002/mrm.28118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 01/09/2023]
Abstract
PURPOSE The vascular blood flow in brown adipose tissue (BAT) is important for handling triglyceride clearance, increased blood flow and oxygenation. We used dynamic contrast-enhanced (DCE)-MRI and fat fraction (FF) imaging for investigating vascular perfusion kinetics in brown and beige adipose tissues with cold exposure or treatment with β3-adrenergic agonist. METHODS FF imaging and DCE-MRI using gadolinium-diethylenetriaminepentaacetic acid were performed in interscapular BAT (iBAT) and beige tissues using male Wister rats (n = 38). Imaging was performed at thermoneutral condition and with either cold exposure, treatment with pharmacological agent CL-316,243, or saline. DCE-MRI and FF data were co-registered to enhance the understanding of metabolic activity. RESULTS Uptake of contrast agent in activated iBAT and beige tissues were significantly (P < .05) higher than nonactivated iBAT. The Ktrans and kep increased significantly in iBAT and beige tissues after treatment with either cold exposure or β3-adrenergic agonist. The FF decreased in activated iBAT and beige tissues. The Ktrans and FF from iBAT and beige tissues were inversely correlated (r = 0.97; r = 0.94). Significant increase in vascular endothelial growth factor expression and Ktrans in activated iBAT and beige tissues were in agreement with the increased vasculature and vascular perfusion kinetics. The iBAT and beige tissues were validated by measuring molecular markers. CONCLUSION Increased Ktrans and decreased FF in iBAT and beige tissues were in agreement with the vascular perfusion kinetics facilitating the clearance of free fatty acids. The methodology can be extended for the screening of browning agents.
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Affiliation(s)
- Jadegoud Yaligar
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | - Sanjay Kumar Verma
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | - Venkatesh Gopalan
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | - Rengaraj Anantharaj
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | - Giang Thi Thu Le
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | - Kavita Kaur
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore
| | | | - Melvin Khee-Shing Leow
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore.,Cardiovascular and Metabolic Disorder Program, Duke-NUS.,Singapore Institute for Clinical Sciences, Singapore
| | - S Sendhil Velan
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A*STAR), Singapore.,Department of Physiology, National University of Singapore, Singapore.,Singapore Institute for Clinical Sciences, Singapore.,Department of Medicine, National University of Singapore, Singapore
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10
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Gullberg GT, Shrestha UM, Seo Y. Dynamic cardiac PET imaging: Technological improvements advancing future cardiac health. J Nucl Cardiol 2019; 26:1292-1297. [PMID: 29388118 PMCID: PMC6068005 DOI: 10.1007/s12350-018-1201-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 01/15/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Grant T Gullberg
- Department of Radiology and Biomedical Imaging, University of California, 185 Berry St., Ste 350, San Francisco, CA, 94143-0946, USA.
| | - Uttam M Shrestha
- Department of Radiology and Biomedical Imaging, University of California, 185 Berry St., Ste 350, San Francisco, CA, 94143-0946, USA
| | - Youngho Seo
- Department of Radiology and Biomedical Imaging, University of California, 185 Berry St., Ste 350, San Francisco, CA, 94143-0946, USA
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11
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Watabe T, Hatazawa J. Evaluation of Functional Connectivity in the Brain Using Positron Emission Tomography: A Mini-Review. Front Neurosci 2019; 13:775. [PMID: 31402852 PMCID: PMC6676772 DOI: 10.3389/fnins.2019.00775] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/10/2019] [Indexed: 11/13/2022] Open
Abstract
Resting-state networks (RSNs) exhibit spontaneous functional connectivity in the resting state. Previous studies have evaluated RSNs mainly based on spontaneous fluctuations in blood oxygenation level-dependent (BOLD) signals during functional magnetic resonance imaging (fMRI). However, separation between regional increases in cerebral blood flow (CBF) and oxygen consumption is theoretically difficult using BOLD-fMRI. Such separation can be achieved using quantitative 15O-gas and water positron emission tomography (PET). In addition, 18F-FDG PET can be used to investigate functional connectivity based on changes in glucose metabolism, which reflects local brain activity. Previous studies have highlighted the feasibility and clinical usefulness of 18F-FDG-PET for the analysis of RSNs, and recent studies have utilized simultaneous PET/fMRI for such analyses. While PET provides seed information regarding the focus of the abnormalities (e.g., hypometabolism and reduced target binding), fMRI is used for the analysis of functional connectivity. Thus, as PET and fMRI provide different types of information, integrating these modalities may aid in elucidating the pathological mechanisms underlying certain diseases, and in characterizing individual patients.
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Affiliation(s)
- Tadashi Watabe
- Department of Nuclear Medicine and Tracer Kinetics, Graduate School of Medicine, Osaka University, Osaka, Japan.,Institute for Radiation Sciences, Osaka University, Osaka, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Graduate School of Medicine, Osaka University, Osaka, Japan.,Institute for Radiation Sciences, Osaka University, Osaka, Japan
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12
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Sivasubramanian M, Chuang YC, Chen NT, Lo LW. Seeing Better and Going Deeper in Cancer Nanotheranostics. Int J Mol Sci 2019; 20:E3490. [PMID: 31315232 PMCID: PMC6678689 DOI: 10.3390/ijms20143490] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 02/07/2023] Open
Abstract
Biomedical imaging modalities in clinical practice have revolutionized oncology for several decades. State-of-the-art biomedical techniques allow visualizing both normal physiological and pathological architectures of the human body. The use of nanoparticles (NP) as contrast agents enabled visualization of refined contrast images with superior resolution, which assists clinicians in more accurate diagnoses and in planning appropriate therapy. These desirable features are due to the ability of NPs to carry high payloads (contrast agents or drugs), increased in vivo half-life, and disease-specific accumulation. We review the various NP-based interventions for treatments of deep-seated tumors, involving "seeing better" to precisely visualize early diagnosis and "going deeper" to activate selective therapeutics in situ.
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Affiliation(s)
- Maharajan Sivasubramanian
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 350, Taiwan
| | - Yao Chen Chuang
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 350, Taiwan
| | - Nai-Tzu Chen
- Department of Cosmeceutics, China Medical University, Taichung 40402, Taiwan.
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan.
| | - Leu-Wei Lo
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 350, Taiwan.
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13
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van der Bijl P, Vo NM, Kostyukevich MV, Mertens B, Ajmone Marsan N, Delgado V, Bax JJ. Prognostic implications of global, left ventricular myocardial work efficiency before cardiac resynchronization therapy. Eur Heart J Cardiovasc Imaging 2019; 20:1388-1394. [DOI: 10.1093/ehjci/jez095] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/09/2019] [Indexed: 11/12/2022] Open
Abstract
Abstract
Aims
Cardiac resynchronization therapy (CRT) restores mechanical efficiency to the failing left ventricular (LV) by resynchronization of contraction. Global, LV myocardial work efficiency (GLVMWE) can be quantified non-invasively with echocardiography. The prognostic implication of GLVMWE remains unexplored, and we therefore related GLVMWE before CRT to long-term prognosis.
Methods and results
Data were analysed from an ongoing registry of patients with Class I indications for CRT. GLVMWE was defined as the ratio of constructive work in all LV segments, divided by the sum of constructive and wasted work in all LV segments, as a percentage. It was derived from speckle tracking strain echocardiography and non-invasive blood pressure measurements, taken pre-CRT. Patients were dichotomized according to baseline, median GLVMWE [75%; interquartile range (IQR) 66–81%]. A total of 153 patients (66 ± 10 years, 72% male, 48% ischaemic heart disease) were analysed. After a median follow-up of 57 months (IQR 28–76 months), 31% of patients died. CRT recipients with less efficient baseline energetics (GLVMWE <75%) demonstrated lower event rates than patients with more efficient baseline energetics (GLVMWE ≥75%) (log-rank test, P = 0.029). On multivariable analysis, global LV wasted work ratio <75% pre-CRT was independently associated with a decreased risk of all-cause mortality (hazard ratio 0.48, 95% confidence interval 0.25–0.92; P = 0.027), suggesting that the potential for improvement in LV efficiency is important for CRT benefit.
Conclusion
GLVMWE can be derived non-invasively from speckle tracking strain echocardiography and non-invasive blood pressure recordings. A lower GLVMWE before CRT is independently associated with improved long-term outcome.
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Affiliation(s)
- Pieter van der Bijl
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Ngoc Mai Vo
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Marina V Kostyukevich
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
- FSBO “NMRC of Cardiology” of the Ministry of Healthcare of the Russian Federation, 3rd Cherepkovskaya Street, 15A, 121552 Moscow, Russian Federation
| | - Bart Mertens
- Bioinformatics Center of Expertise, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Nina Ajmone Marsan
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Victoria Delgado
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Jeroen J Bax
- Department of Cardiology, Heart Lung Center, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
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14
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Sônego F, Bouccara S, Pons T, Lequeux N, Danckaert A, Tinevez JY, Alam IS, Shorte SL, Tournebize R. Imaging of Red-Shifted Light From Bioluminescent Tumors Using Fluorescence by Unbound Excitation From Luminescence. Front Bioeng Biotechnol 2019; 7:73. [PMID: 31024905 PMCID: PMC6460942 DOI: 10.3389/fbioe.2019.00073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/15/2019] [Indexed: 12/02/2022] Open
Abstract
Early detection of tumors is today a major challenge and requires sensitive imaging methodologies coupled with new efficient probes. In vivo optical bioluminescence imaging has been widely used in the field of preclinical oncology to visualize tumors and several cancer cell lines have been genetically modified to provide bioluminescence signals. However, the light emitted by the majority of commonly used luciferases is usually in the blue part of the visible spectrum, where tissue absorption is still very high, making deep tissue imaging non-optimal, and calling for optimized optical imaging methodologies. We have previously shown that red-shifting of bioluminescence signal by Fluorescence Unbound Excitation from Luminescence (FUEL) is a mean to increase bioluminescence signal sensitivity detection in vivo. Here, we applied FUEL to tumor detection in two different subcutaneous tumor models: the auto-luminescent human embryonic kidney (HEK293) cell line and the murine B16-F10 melanoma cell line previously transfected with a plasmid encoding the Luc2 firefly luciferase. Tumor size and bioluminescence were measured over time and tumor vascularization characterized. We then locally injected near infrared emitting Quantum Dots (NIR QDs) in the tumor site and observed a red-shifting of bioluminescence signal by (FUEL) indicating that FUEL could be used to allow deeper tumor detection in mice.
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Affiliation(s)
- Fabiane Sônego
- UTechS Photonic BioImaging, C2RT, Institut Pasteur, Paris, France
| | - Sophie Bouccara
- UTechS Photonic BioImaging, C2RT, Institut Pasteur, Paris, France
| | - Thomas Pons
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, CNRS UMR8213, PSL Research University, Université Pierre et Marie Curie, Sorbonne-Universités, Paris, France
| | - Nicolas Lequeux
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, CNRS UMR8213, PSL Research University, Université Pierre et Marie Curie, Sorbonne-Universités, Paris, France
| | - Anne Danckaert
- UTechS Photonic BioImaging, C2RT, Institut Pasteur, Paris, France
| | | | - Israt S. Alam
- UTechS Photonic BioImaging, C2RT, Institut Pasteur, Paris, France
| | | | - Régis Tournebize
- UTechS Photonic BioImaging, C2RT, Unité Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, Paris, France
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15
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Meester EJ, Krenning BJ, de Swart J, Segbers M, Barrett HE, Bernsen MR, Van der Heiden K, de Jong M. Perspectives on Small Animal Radionuclide Imaging; Considerations and Advances in Atherosclerosis. Front Med (Lausanne) 2019; 6:39. [PMID: 30915335 PMCID: PMC6421263 DOI: 10.3389/fmed.2019.00039] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022] Open
Abstract
This review addresses nuclear SPECT and PET imaging in small animals in relation to the atherosclerotic disease process, one of our research topics of interest. Imaging of atherosclerosis in small animal models is challenging, as it operates at the limits of current imaging possibilities regarding sensitivity, and spatial resolution. Several topics are discussed, including technical considerations that apply to image acquisition, reconstruction, and analysis. Moreover, molecules developed for or applied in these small animal nuclear imaging studies are listed, including target-directed molecules, useful for imaging organs or tissues that have elevated expression of the target compared to other tissues, and molecules that serve as substrates for metabolic processes. Differences between animal models and human pathophysiology that should be taken into account during translation from animal to patient as well as differences in tracer behavior in animal vs. man are also described. Finally, we give a future outlook on small animal radionuclide imaging in atherosclerosis, followed by recommendations. The challenges and solutions described might be applicable to other research fields of health and disease as well.
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Affiliation(s)
- Eric J Meester
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands.,Department of Biomedical Engineering, Thorax Center, Erasmus Medical Center, Rotterdam, Netherlands
| | - B J Krenning
- Department of Cardiology, Thorax Center, Erasmus Medical Center, Rotterdam, Netherlands
| | - J de Swart
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands
| | - M Segbers
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands
| | - H E Barrett
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands.,Department of Biomedical Engineering, Thorax Center, Erasmus Medical Center, Rotterdam, Netherlands
| | - M R Bernsen
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands
| | - K Van der Heiden
- Department of Biomedical Engineering, Thorax Center, Erasmus Medical Center, Rotterdam, Netherlands
| | - Marion de Jong
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, Netherlands
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16
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Parl C, Kolb A, Stricker-Shaver D, Pichler BJ. Dual layer doI detector modules for a dedicated mouse brain PET/MRI. Phys Med Biol 2019; 64:055004. [PMID: 30654339 DOI: 10.1088/1361-6560/aaff73] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The outcome of preclinical imaging studies are enhanced by simultaneous, high-resolution anatomical and molecular data, which advanced PET/MRI systems provide. Nevertheless, mapping of neuroreceptors and accurate quantification of PET tracer distribution in mouse brains is not trivial. The restricted spatial resolution and sensitivity in commercial animal PET systems limits the image quality and the quantification accuracy. We are currently developing a PET/MRI system dedicated for mouse brain studies. The PET system will offer system dimensions of approx. 30 mm in diameter and an axial length of more than 38 mm. This work discusses two system geometries including their associated block detectors. Both configurations were based on a dual layer offset structure with small crystals sizes, in the order of 1 × 1 × 4/6 mm3, to provide discrete depth of interaction information. The detector for configuration 'A' was based on a 4 × 4 silicon photomultiplier (SiPM) array attached to an optical diffusor, and a 12 × 12 as well as a 9 × 11 LSO crystal array, to achieve optimal system sensitivity. This configuration was evaluated by a double layer of 12 × 12 crystals. Configuration 'B' was composed of three 2 × 2 SiPM arrays equipped with a 1 mm diffusor to read out an LSO stack of 20 × 6 and 19 × 5 individual crystals. The average peak-to-valley ratio of the inner/outer layer was 3.5/3.6 for detector 'A', and 3.4/2.8 for detector 'B'. The average full width at half maximum (FWHM) energy resolution of the block detectors were 22.24% ± 3.36% for 'A' and 30.67% ± 5.37% for 'B'. The FWHM of the full block timing resolution of the inner/outer layer was 1.4 ns/1.2 ns for detector 'A' and 1.8 ns/1.4 ns for 'B'. The performance of the crystal position profile, the energy, and timing resolution indicate that configuration 'A' is more appropriate for a mouse brain PET/MRI system.
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Affiliation(s)
- C Parl
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076 Tuebingen, Germany
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17
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Maier FC, Wild AM, Kirchen N, Holm F, Fuchs K, Schwenck J, Maurer A, Wiehr S. Comparative immuno-Cerenkov luminescence and -PET imaging enables detection of PSMA+ tumors in mice using 64Cu-radiolabeled monoclonal antibodies. Appl Radiat Isot 2019; 143:149-155. [DOI: 10.1016/j.apradiso.2018.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 07/12/2018] [Accepted: 09/07/2018] [Indexed: 01/29/2023]
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18
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19
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Aiello M, Cavaliere C, Marchitelli R, d'Albore A, De Vita E, Salvatore M. Hybrid PET/MRI Methodology. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 141:97-128. [PMID: 30314608 DOI: 10.1016/bs.irn.2018.07.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The hybrid PET/MR scanner represents the first implementation of the effective integration of two modalities allowing truly synchronous/simultaneous acquisition of their imaging signals. This integration, resulting from the innovation and development of specific hardware components has paved the way for new approaches in the study of neurodegenerative diseases. This chapter will describe the hardware development that has led to the availability of different clinical solutions for PET/MR imaging as well as the still-open technological challenges and opportunities related to the processing and exploitation of the simultaneous acquisition in neurological studies.
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Affiliation(s)
| | | | | | | | - Enrico De Vita
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
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20
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Current Clinical Practice Patterns of Self-Identified Nuclear Medicine Specialists. AJR Am J Roentgenol 2018; 211:978-985. [PMID: 30085843 DOI: 10.2214/ajr.18.20005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of our study was to study patterns of services rendered by U.S. physicians who self-identify as nuclear medicine (NM) specialists. MATERIALS AND METHODS Recent Medicare physician claims and demographic files were obtained and linked. NM specialists were defined as physicians self-identifying NM as their primary specialty on claims or as any of their specialties during enrollment. Using other self-identified specialties, we classified physicians as nuclear radiologists, nuclear cardiologists, exclusively NM physicians, or Others. Our primary outcome measure was the percentage of NM effort (in work relative value units [WRVUs]) per physician per specialty group. Secondary outcome measures included physician sociodemographic parameters and most common uniquely rendered services. RESULTS Nationally, 1583 physicians self-identified as NM specialists during the calendar years 2012 through 2015. The distribution of WRVUs attributed to NM varied widely by specialty group; most nuclear radiologists and nuclear cardiologists devoted 10% or less of their effort to NM services whereas most NM physicians devoted 90% or more of their effort to NM services. NM specialists were most commonly nuclear radiologists (52.2%) and men (80.3%) and practiced in urban (98.4%) and nonacademic settings (62.9%). NM physicians interpreted more general NM studies, nuclear radiologists interpreted more cross-sectional imaging studies, and nuclear cardiologists interpreted mostly nuclear cardiology studies, with a majority of their overall work attributed to clinical evaluation and management (E/M). E/M services accounted for less than 2% of WRVUs for both nuclear radiologists and NM physicians. CONCLUSION The work patterns of U.S. NM specialists is highly variable. Most NM physicians practice 90% or more NM, whereas most nuclear radiologists and nuclear cardiologists practice 10% or less NM. Commonly performed services vary considerably by specialty group.
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21
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Madru R, Budassi M, Benveniste H, Lee H, Smith SD, Schlyer DJ, Vaska P, Knutsson L, Strand SE. Simultaneous Preclinical Positron Emission Tomography-Magnetic Resonance Imaging Study of Lymphatic Drainage of Chelator-Free 64Cu-Labeled Nanoparticles. Cancer Biother Radiopharm 2018; 33:213-220. [PMID: 30036073 DOI: 10.1089/cbr.2017.2412] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Hybrid positron emission tomography (PET)-magnetic resonance imaging (MRI) systems have been taken in use as new clinical diagnostic tools including detection and therapy planning of cancer. To reduce the amount of contrast agents injected in patients while fully benefitting both modalities, dual-modality probes are required. MATERIAL AND METHODS This study was first aimed at developing a hybrid PET-MRI probe by labeling superparamagnetic iron oxide nanoparticles (SPIONs) with 64Cu using a fast and chelator-free conjugation method, and second, to demonstrate the ability of the agent to target sentinel lymph nodes (SLNs) in vivo using simultaneous PET-MRI imaging. RESULTS High labeling efficiency of 97% produced within 10-15 min was demonstrated at room temperature. 64Cu-SPIONs were chemically stable in mouse serum for 24 h and after intradermal injection in the hind paw of C57BL/6J mice, demonstrated specific accumulation in the SLN. Simultaneous PET-MRI clearly demonstrated visualization of 64Cu-SPIONs, in dynamic and static imaging sequences up to 24 h after administration. CONCLUSION The use of a single hybrid probe and simultaneous hybrid imaging provides an efficient, complementary integration of quantitation and is expected to improve preoperative planning and intraoperative guidance of cancer treatments.
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Affiliation(s)
- Renata Madru
- 1 Department of Clinical Sciences Lund, Medical Radiation Physics, Lund University , Lund, Sweden
| | - Michael Budassi
- 2 Department of Biomedical Engineering, Stony Brook University , Stony Brook, New York.,3 Department of Biosciences, Brookhaven National Laboratory , Brookhaven, New York
| | - Helene Benveniste
- 4 Department of Anesthesiology, Yale University , New Haven, Connecticut
| | - Hedok Lee
- 4 Department of Anesthesiology, Yale University , New Haven, Connecticut
| | - S David Smith
- 3 Department of Biosciences, Brookhaven National Laboratory , Brookhaven, New York
| | - David J Schlyer
- 3 Department of Biosciences, Brookhaven National Laboratory , Brookhaven, New York
| | - Paul Vaska
- 2 Department of Biomedical Engineering, Stony Brook University , Stony Brook, New York
| | - Linda Knutsson
- 1 Department of Clinical Sciences Lund, Medical Radiation Physics, Lund University , Lund, Sweden
| | - Sven-Erik Strand
- 1 Department of Clinical Sciences Lund, Medical Radiation Physics, Lund University , Lund, Sweden .,5 Department of Clinical Sciences Lund, Oncology and Pathology, Lund University , Lund, Sweden
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22
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Vrigneaud JM, McGrath J, Courteau A, Pegg R, Gomis ASP, Camacho A, Martin G, Schramm N, Brunotte F. Initial performance evaluation of a preclinical PET scanner available as a clip-on assembly in a sequential PET/MRI system. Phys Med Biol 2018; 63:125007. [PMID: 29762132 DOI: 10.1088/1361-6560/aac4f7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We evaluated the performance characteristics of a prototype preclinical PET scanner available as an easy clippable assembly that can dock to an MRI system. The single ring version of the PET system consists of eight detectors, each of which comprises a 12 × 12 silicon photomultipliers (SiPMs) array coupled with a dual layer of offset scintillation crystals to measure depth of interaction. The crystal arrays have 29 × 29 (30 × 30 for the outer layer) 4 mm long LYSO crystals (6 mm for the outer layer). The ring diameter is 119.2 mm and the axial field of view is 50.4 mm. The NEMA NU 4-2008 protocol was followed for studying the PET performance. Temperature stability of SiPMs was also investigated. The peak system absolute sensitivity was 4.70% with an energy window of 250-750 keV. The spatial resolution was 1.28/1.88/1.85 mm FWHM (radial/tangential/axial) at a distance of 5 mm from the center. Peak noise equivalent counting rate and scatter fraction for mouse phantom were 61.9 kcps at 14.9 MBq and 21.0%, respectively. The uniformity was 6.3% and the spill-over ratios in the images of the water-and air-filled chambers were 0.07 and 0.17, respectively. Recovery coefficients ranged from 0.13 to 0.96. Change in sensitivity as a function of ambient temperature was 0.3%/°C. These first results indicate excellent spatial resolution performance for use with animal studies. Moreover, the clippable assembly can be upgraded to accept a second ring of SiPMs modules, leading to improved sensitivity and axial coverage.
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Affiliation(s)
- J M Vrigneaud
- Department of Nuclear Medicine, Georges-Francois LECLERC Cancer Center, UNICANCER, Dijon, France
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23
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Napieczynska H, Kolb A, Katiyar P, Tonietto M, Ud-Dean M, Stumm R, Herfert K, Calaminus C, Pichler BJ. Impact of the Arterial Input Function Recording Method on Kinetic Parameters in Small-Animal PET. J Nucl Med 2018; 59:1159-1164. [PMID: 29476003 DOI: 10.2967/jnumed.117.204164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/25/2018] [Indexed: 11/16/2022] Open
Abstract
The goal of this study was to validate the use of an MR-compatible blood sampler (BS) with a detector system based on a lutetium oxyorthosilicate scintillator and avalanche photodiodes for small-animal PET. Methods: Five rats underwent a 60-min 18F-FDG study. For each animal, the arterial input function (AIF) was derived from the BS recording, from manual sampling (MS), and from the PET image. These AIFs were applied for kinetic modeling of the striatum using the irreversible 2-tissue-compartment model. The MS-based technique with a dispersion correction served as a reference approach, and the kinetic parameters that were estimated with the BS- and the image-derived AIFs were compared with the reference values. Additionally, the effect of applying a population-based activity ratio for plasma to whole blood (p/wb) and the dispersion correction was assessed. Results: The K1, k2, and k3 values estimated with the reference approach were 0.174 ± 0.037 mL/min/cm3, 0.342 ± 0.080 1/min, and 0.048 ± 0.009 1/min, respectively. The corresponding parameters obtained with the BS- and image-derived AIFs deviated from these values by 0.6%-18.8% and 16.7%-47.9%, respectively. To compensate for the error in the BS-based technique, data from one MS collected at the end of the experiment were combined with the data from the first 10 min of the BS recording. This approach reduced the deviation in the kinetic parameters to 1.8%-6.3%. Using p/wb led to a 1.7%-8.3% difference from the reference parameters. The sensitivity of the BS was 23%, the energy resolution for the 511-keV photopeak was 19%, and the timing resolution was 11.2 ns. Conclusion: Online recording of the blood activity level with the BS allows precise measurement of AIF, without loss of blood volume. Combining the BS data with one MS is the most accurate approach for the data analysis. The high sensitivity of the device may allow application of lower radioactivity doses.
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Affiliation(s)
- Hanna Napieczynska
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany .,International Max Planck Research School for Cognitive and Systems Neuroscience, Tuebingen, Germany; and
| | - Armin Kolb
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Prateek Katiyar
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Matteo Tonietto
- Institute for Brain and Spinal Cord, Sorbonne University, UPMC, INSERM U 1127, CNRS UMR 7225, Paris, France
| | - Minhaz Ud-Dean
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Ramona Stumm
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Kristina Herfert
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Carsten Calaminus
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
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24
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Wiehr S, Warnke P, Rolle AM, Schütz M, Oberhettinger P, Kohlhofer U, Quintanilla-Martinez L, Maurer A, Thornton C, Boschetti F, Reischl G, Autenrieth IB, Pichler BJ, Autenrieth SE. New pathogen-specific immunoPET/MR tracer for molecular imaging of a systemic bacterial infection. Oncotarget 2017; 7:10990-1001. [PMID: 26934329 PMCID: PMC4905453 DOI: 10.18632/oncotarget.7770] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/20/2016] [Indexed: 01/12/2023] Open
Abstract
The specific and rapid detection of Enterobacteriaceae, the most frequent cause of gram-negative bacterial infections in humans, remains a major challenge. We developed a non-invasive method to rapidly detect systemic Yersinia enterocolitica infections using immunoPET (antibody-targeted positron emission tomography) with [64Cu]NODAGA-labeled Yersinia-specific polyclonal antibodies targeting the outer membrane protein YadA. In contrast to the tracer [18F]FDG, [64Cu]NODAGA-YadA uptake co-localized in a dose dependent manner with bacterial lesions of Yersinia-infected mice, as detected by magnetic resonance (MR) imaging. This was accompanied by elevated uptake of [64Cu]NODAGA-YadA in infected tissues, in ex vivo biodistribution studies, whereas reduced uptake was observed following blocking with unlabeled anti-YadA antibody. We show, for the first time, a bacteria-specific, antibody-based, in vivo imaging method for the diagnosis of a Gram-negative enterobacterial infection as a proof of concept, which may provide new insights into pathogen-host interactions.
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Affiliation(s)
- Stefan Wiehr
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Philipp Warnke
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University, Tübingen, Germany.,Institute of Medical Microbiology, Virology and Hygiene, Rostock University Hospital, Rostock, Germany
| | - Anna-Maria Rolle
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Monika Schütz
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University, Tübingen, Germany
| | - Philipp Oberhettinger
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University, Tübingen, Germany
| | - Ursula Kohlhofer
- Institute of Pathology, Eberhard Karls University Tübingen, Tübingen, Germany
| | | | - Andreas Maurer
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Christopher Thornton
- Biosciences and ISCA Diagnostics Ltd., University of Exeter, Exeter, United Kingdom
| | | | - Gerald Reischl
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Ingo B Autenrieth
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University, Tübingen, Germany
| | - Bernd J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Stella E Autenrieth
- Department of Internal Medicine II, University Hospital Tübingen, Tübingen, Germany
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25
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Abstract
Currently, the differential diagnosis between atypical parkinsonisms and classical idiopathic Parkinson's disease can be quite difficult because of the significant overlap of clinical presentation and symptoms. Neurodegenerative conditions, including progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and frontotemporal dementia (FTD), are primarily characterized by accumulation of tau protein in the brain. Recent imaging developments for tau pathology may provide a promising tool for the assessment of diagnosis, prognosis, and progression of these neurodegenerative disorders. This review will survey PET studies to describe the recent advances in the imaging of tau pathology in PSP, CBD, and FTD.
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Affiliation(s)
- Mikaeel Valli
- a Research Imaging Centre , Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto , Toronto , ON , Canada.,b Division of Brain, Imaging and Behaviour-Systems Neuroscience , Krembil Research Institute, UHN, University of Toronto , Toronto , ON , Canada.,c Institute of Medical Science , University of Toronto , Toronto , ON , Canada
| | - Antonio P Strafella
- a Research Imaging Centre , Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto , Toronto , ON , Canada.,b Division of Brain, Imaging and Behaviour-Systems Neuroscience , Krembil Research Institute, UHN, University of Toronto , Toronto , ON , Canada.,c Institute of Medical Science , University of Toronto , Toronto , ON , Canada.,d Morton and Gloria Shulman Movement Disorder Unit & E.J. Safra Parkinson Disease Program, Neurology Division, Department of Medicine , Toronto Western Hospital, UHN, University of Toronto , Toronto , ON , Canada
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26
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Parl C, Kolb A, Schmid AM, Wehrl HF, Disselhorst JA, Soubiran PD, Stricker-Shaver D, Pichler BJ. A novel optically transparent RF shielding for fully integrated PET/MRI systems. ACTA ACUST UNITED AC 2017; 62:7357-7378. [DOI: 10.1088/1361-6560/aa8384] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hage C, Gremse F, Griessinger CM, Maurer A, Hoffmann SH, Osl F, Pichler BJ, Kiessling F, Scheuer W, Pöschinger T. Comparison of the Accuracy of FMT/CT and PET/MRI for the Assessment of Antibody Biodistribution in Squamous Cell Carcinoma Xenografts. J Nucl Med 2017; 59:44-50. [DOI: 10.2967/jnumed.117.197178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/25/2017] [Indexed: 11/16/2022] Open
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Vrigneaud JM, Walker P, Barbier B, Camacho A, Oudot A, Collin B, Brunotte F. Performance evaluation of the PET component of a sequential APD-based micro-PET/MR imaging system. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa686d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sahlholm K, Ielacqua GD, Xu J, Jones LA, Schlegel F, Mach RH, Rudin M, Schroeter A. The role of beta-arrestin2 in shaping fMRI BOLD responses to dopaminergic stimulation. Psychopharmacology (Berl) 2017; 234:2019-2030. [PMID: 28382543 PMCID: PMC5486931 DOI: 10.1007/s00213-017-4609-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/18/2017] [Indexed: 01/11/2023]
Abstract
RATIONALE The dopamine D2 receptor (D2R) couples to inhibitory Gi/o proteins and is targeted by antipsychotic and antiparkinsonian drugs. Beta-arrestin2 binds to the intracellular regions of the agonist-occupied D2R to terminate G protein activation and promote internalization, but also to initiate downstream signaling cascades which have been implicated in psychosis. Functional magnetic resonance imaging (fMRI) has proven valuable for measuring dopamine receptor-mediated changes in neuronal activity, and might enable beta-arrestin2 function to be studied in vivo. OBJECTIVES The present study examined fMRI blood oxygenation level dependent (BOLD) signal changes elicited by a dopamine agonist in wild-type (WT) and beta-arrestin2 knockout (KO) mice, to investigate whether genetic deletion of beta-arrestin2 prolongs or otherwise modifies D2R-dependent responses. METHODS fMRI BOLD data were acquired on a 9.4 T system. During scans, animals received 0.2 mg/kg apomorphine, i.v. In a subset of experiments, animals were pretreated with 2 mg/kg of the D2R antagonist, eticlopride. RESULTS Following apomorphine administration, BOLD signal decreases were observed in caudate/putamen of WT and KO animals. The time course of response decay in caudate/putamen was significantly slower in KO vs. WT animals. In cingulate cortex, an initial BOLD signal decrease was followed by a positive response component in WT but not in KO animals. Eticlopride pretreatment significantly reduced apomorphine-induced BOLD signal changes. CONCLUSIONS The prolonged striatal response decay rates in KO animals might reflect impaired D2R desensitization, consistent with the known function of beta-arrestin2. Furthermore, the apomorphine-induced positive response component in cingulate cortex may depend on beta-arrestin2 signaling downstream of D2R.
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Affiliation(s)
- Kristoffer Sahlholm
- Institute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093, Zurich, Switzerland. .,Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St. Louis, MO, 63110, USA. .,Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden.
| | - Giovanna D. Ielacqua
- 0000 0001 2156 2780grid.5801.cInstitute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland
| | - Jinbin Xu
- 0000 0001 2355 7002grid.4367.6Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St. Louis, MO 63110 USA
| | - Lynne A. Jones
- 0000 0001 2355 7002grid.4367.6Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St. Louis, MO 63110 USA
| | - Felix Schlegel
- 0000 0001 2156 2780grid.5801.cInstitute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland
| | - Robert H. Mach
- 0000 0004 1936 8972grid.25879.31Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA 19104 USA
| | - Markus Rudin
- 0000 0001 2156 2780grid.5801.cInstitute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ,0000 0001 2156 2780grid.5801.cNeuroscience Center Zurich, University and ETH Zurich, Winterthurer-Str. 190, 8057 Zurich, Switzerland ,0000 0004 1937 0650grid.7400.3Institute of Pharmacology and Toxicology, University of Zurich, Winterthurer-Str. 190, 8057 Zurich, Switzerland
| | - Aileen Schroeter
- 0000 0001 2156 2780grid.5801.cInstitute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ,0000 0001 2156 2780grid.5801.cNeuroscience Center Zurich, University and ETH Zurich, Winterthurer-Str. 190, 8057 Zurich, Switzerland
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Wiehr S, Rolle AM, Warnke P, Kohlhofer U, Quintanilla-Martinez L, Reischl G, Autenrieth IB, Pichler BJ, Autenrieth SE. The Positron Emission Tomography Tracer 3'-Deoxy-3'-[18F]Fluorothymidine ([18F]FLT) Is Not Suitable to Detect Tissue Proliferation Induced by Systemic Yersinia enterocolitica Infection in Mice. PLoS One 2016; 11:e0164163. [PMID: 27701464 PMCID: PMC5049782 DOI: 10.1371/journal.pone.0164163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/20/2016] [Indexed: 11/25/2022] Open
Abstract
Most frequently, gram-negative bacterial infections in humans are caused by Enterobacteriaceae and remain a major challenge in medical diagnostics. We non-invasively imaged moderate and severe systemic Yersinia enterocolitica infections in mice using the positron emission tomography (PET) tracer 3’-deoxy-3’-[18F]fluorothymidine ([18F]FLT), which is a marker of proliferation, and compared the in vivo results to the ex vivo biodistributions, bacterial loads, and histologies of the corresponding organs. Y. enterocolitica infection is detectable with histology using H&E staining and immunohistochemistry for Ki 67. [18F]FLT revealed only background uptake in the spleen, which is the main manifestation site of systemic Y. enterocolitica-infected mice. The uptake was independent of the infection dose. Antibody-based thymidine kinase 1 (Tk-1) staining confirmed the negative [18F]FLT-PET data. Histological alterations of spleen tissue, observed via Ki 67-antibody-based staining, can not be detected by [18F]FLT-PET in this model. Thus, the proliferation marker [18F]FLT is not a suitable tracer for the diagnosis of systemic Y. enterocolitica infection in the C57BL/6 animal model of yersiniosis.
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Affiliation(s)
- Stefan Wiehr
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anna-Maria Rolle
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Philipp Warnke
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University Tübingen, Tübingen, Germany
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Ursula Kohlhofer
- Institute of Pathology, Eberhard Karls University Tübingen, Tübingen, Germany
| | | | - Gerald Reischl
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Ingo B. Autenrieth
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Bernd J. Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Stella E. Autenrieth
- Department of Internal Medicine II, University Hospital Tübingen, Tübingen, Germany
- * E-mail:
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Abstract
PURPOSE OF REVIEW This article provides an overview of the recent literature regarding the application of in-vivo brain imaging techniques to animal models of ischemic stroke. RECENT FINDINGS Major breakthroughs concerned the effects of sensory stimulation on neuronal function, local hemodynamics, and tissue outcome in the hyperacute phase of stroke; the novel application to stroke of hybrid scanners allowing simultaneous PET and magnetic resonance; the refinements of magnetic resonance-based oxygen imaging, allowing to map the ischemic penumbra in a completely noninvasive way; the implementation of new PET ligands to selectively map poststroke neuronal death and neuroinflammation; and the use of novel mesoscale imaging techniques to demonstrate the major role of interhemispheric connectivity in poststroke plasticity and functional recovery. SUMMARY The array of techniques to map in vivo the key pathophysiological brain processes involved in stroke is currently enlarging at an amazing pace. This is paralleled by ever-increasing sophistication in postprocessing tools. The combination of techniques allowing simultaneous access to several variables is particularly powerful as it affords unprecedented insights into the intimate processes underlying the tissue and neuronal changes that follow a stroke. These major leaps forward will hopefully lead to therapeutic breakthroughs aiming at improving functional outcome after stroke.
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Longo DL, Bartoli A, Consolino L, Bardini P, Arena F, Schwaiger M, Aime S. In Vivo Imaging of Tumor Metabolism and Acidosis by Combining PET and MRI-CEST pH Imaging. Cancer Res 2016; 76:6463-6470. [PMID: 27651313 DOI: 10.1158/0008-5472.can-16-0825] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 08/13/2016] [Accepted: 08/15/2016] [Indexed: 11/16/2022]
Abstract
The vast majority of cancers exhibit increased glucose uptake and glycolysis regardless of oxygen availability. This metabolic shift leads to an enhanced production of lactic acid that decreases extracellular pH (pHe), a hallmark of the tumor microenvironment. In this way, dysregulated tumor pHe and upregulated glucose metabolism are linked tightly and their relative assessment may be useful to gain understanding of the underlying biology. Here we investigated noninvasively the in vivo correlation between tumor 18F-FDG uptake and extracellular pH values in a murine model of HER2+ breast cancer. Tumor extracellular pH and perfusion were assessed by acquiring MRI-CEST (chemical exchange saturation transfer) images on a 3T scanner after intravenous administration of a pH-responsive contrast agent (iopamidol). Static PET images were recorded immediately after MRI acquisitions to quantify the extent of 18F-FDG uptake. We demonstrated the occurrence of tumor pHe changes that report on acidification of the interstitial fluid caused by an accelerated glycolysis. Combined PET and MRI-CEST images reported complementary spatial information of the altered glucose metabolism. Notably, a significant inverse correlation was found between extracellular tumor pH and 18F-FDG uptake, as a high 18F-FDG uptake corresponds to lower extracellular pH values. These results show how merging the information from 18F-FDG-uptake and extracellular pH measurements can improve characterization of the tumor microenvironment. Cancer Res; 76(22); 6463-70. ©2016 AACR.
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Affiliation(s)
- Dario L Longo
- Institute of Biostructure and Bioimaging (CNR) c/o Molecular Biotechnologies Center, Torino, Italy.,Molecular Imaging Center, University of Torino, Torino, Italy
| | - Antonietta Bartoli
- Molecular Imaging Center, University of Torino, Torino, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Lorena Consolino
- Molecular Imaging Center, University of Torino, Torino, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Paola Bardini
- Molecular Imaging Center, University of Torino, Torino, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Francesca Arena
- Molecular Imaging Center, University of Torino, Torino, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Markus Schwaiger
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universitat Munchen, Munich, Germany
| | - Silvio Aime
- Molecular Imaging Center, University of Torino, Torino, Italy. .,Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
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Hyder F, Herman P, Bailey CJ, Møller A, Globinsky R, Fulbright RK, Rothman DL, Gjedde A. Uniform distributions of glucose oxidation and oxygen extraction in gray matter of normal human brain: No evidence of regional differences of aerobic glycolysis. J Cereb Blood Flow Metab 2016; 36:903-16. [PMID: 26755443 PMCID: PMC4853838 DOI: 10.1177/0271678x15625349] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/03/2015] [Indexed: 11/17/2022]
Abstract
Regionally variable rates of aerobic glycolysis in brain networks identified by resting-state functional magnetic resonance imaging (R-fMRI) imply regionally variable adenosine triphosphate (ATP) regeneration. When regional glucose utilization is not matched to oxygen delivery, affected regions have correspondingly variable rates of ATP and lactate production. We tested the extent to which aerobic glycolysis and oxidative phosphorylation power R-fMRI networks by measuring quantitative differences between the oxygen to glucose index (OGI) and the oxygen extraction fraction (OEF) as measured by positron emission tomography (PET) in normal human brain (resting awake, eyes closed). Regionally uniform and correlated OEF and OGI estimates prevailed, with network values that matched the gray matter means, regardless of size, location, and origin. The spatial agreement between oxygen delivery (OEF≈0.4) and glucose oxidation (OGI ≈ 5.3) suggests that no specific regions have preferentially high aerobic glycolysis and low oxidative phosphorylation rates, with globally optimal maximum ATP turnover rates (VATP ≈ 9.4 µmol/g/min), in good agreement with (31)P and (13)C magnetic resonance spectroscopy measurements. These results imply that the intrinsic network activity in healthy human brain powers the entire gray matter with ubiquitously high rates of glucose oxidation. Reports of departures from normal brain-wide homogeny of oxygen extraction fraction and oxygen to glucose index may be due to normalization artefacts from relative PET measurements.
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Affiliation(s)
- Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Christopher J Bailey
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Arne Møller
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - Ronen Globinsky
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Robert K Fulbright
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Albert Gjedde
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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Rolle AM, Soboslay PT, Reischl G, Hoffmann WH, Pichler BJ, Wiehr S. Evaluation of the Metabolic Activity of Echinococcus multilocularis in Rodents Using Positron Emission Tomography Tracers. Mol Imaging Biol 2016; 17:512-20. [PMID: 25561014 DOI: 10.1007/s11307-014-0815-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE 2-Deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) has been used as a standard clinical positron emission tomography (PET) tracer for the follow-up of the rare but life-threatening parasitic disease alveolar echinococcosis (AE). Given that the disease is endemic in many countries in the northern hemisphere and the diagnosis is still challenging, the aim of our study was to evaluate further clinically relevant PET tracers as possible diagnostic tools for AE in vitro and in vivo. PROCEDURES Various clinically used PET tracers were evaluated in vitro and assessed in an in vivo AE animal model based on PET/magnetic resonance (MR) measurements. RESULTS In vitro binding assays displayed high uptake of [(18)F]FDG in a cell suspension of E. multilocularis tissue, whereas 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) and [(11)C]choline were found to be taken up strongly by E. multilocularis vesicles. [(18)F]FDG and [(18)F]FLT displayed an elevated uptake in vivo, which appeared as several foci throughout the parasite tissue as opposed to [(18)F]fluoro-azomycinarabinofuranoside ([(18)F]FAZA) and [(11)C]choline. CONCLUSIONS Our data clearly demonstrate that the clinically applied PET tracer [(18)F]FDG is useful for the diagnosis and disease staging of AE but also has drawbacks in the assessment of currently inactive or metabolically weak parasitic lesions. The different tested PET tracers do not show the potential for the replacement or supplementation of current diagnostic strategies. Hence, there is still the need for novel diagnostic tools.
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Affiliation(s)
- Anna-Maria Rolle
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Röntgenweg 13, 72076, Tübingen, Germany
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Aiello M, Cavaliere C, Salvatore M. Hybrid PET/MR Imaging and Brain Connectivity. Front Neurosci 2016; 10:64. [PMID: 26973446 PMCID: PMC4771762 DOI: 10.3389/fnins.2016.00064] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/10/2016] [Indexed: 12/13/2022] Open
Abstract
In recent years, brain connectivity is gaining ever-increasing interest from the interdisciplinary research community. The study of brain connectivity is characterized by a multifaceted approach providing both structural and functional evidence of the relationship between cerebral regions at different scales. Although magnetic resonance (MR) is the most established imaging modality for investigating connectivity in vivo, the recent advent of hybrid positron emission tomography (PET)/MR scanners paved the way for more comprehensive investigation of brain organization and physiology. Due to the high sensitivity and biochemical specificity of radiotracers, combining MR with PET imaging may enrich our ability to investigate connectivity by introducing the concept of metabolic connectivity and cometomics and promoting new insights on the physiological and molecular bases underlying high-level neural organization. This review aims to describe and summarize the main methods of analysis of brain connectivity employed in MR imaging and nuclear medicine. Moreover, it will discuss practical aspects and state-of-the-art techniques for exploiting hybrid PET/MR imaging to investigate the relationship of physiological processes and brain connectivity.
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Affiliation(s)
- Marco Aiello
- IRCCS SDN, Istituto Ricerca Diagnostica Nucleare Naples, Italy
| | - Carlo Cavaliere
- IRCCS SDN, Istituto Ricerca Diagnostica Nucleare Naples, Italy
| | - Marco Salvatore
- IRCCS SDN, Istituto Ricerca Diagnostica Nucleare Naples, Italy
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36
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ImmunoPET/MR imaging allows specific detection of Aspergillus fumigatus lung infection in vivo. Proc Natl Acad Sci U S A 2016; 113:E1026-33. [PMID: 26787852 DOI: 10.1073/pnas.1518836113] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Invasive pulmonary aspergillosis (IPA) is a life-threatening lung disease caused by the fungus Aspergillus fumigatus, and is a leading cause of invasive fungal infection-related mortality and morbidity in patients with hematological malignancies and bone marrow transplants. We developed and tested a novel probe for noninvasive detection of A. fumigatus lung infection based on antibody-guided positron emission tomography and magnetic resonance (immunoPET/MR) imaging. Administration of a [(64)Cu]DOTA-labeled A. fumigatus-specific monoclonal antibody (mAb), JF5, to neutrophil-depleted A. fumigatus-infected mice allowed specific localization of lung infection when combined with PET. Optical imaging with a fluorochrome-labeled version of the mAb showed colocalization with invasive hyphae. The mAb-based newly developed PET tracer [(64)Cu]DOTA-JF5 distinguished IPA from bacterial lung infections and, in contrast to [(18)F]FDG-PET, discriminated IPA from a general increase in metabolic activity associated with lung inflammation. To our knowledge, this is the first time that antibody-guided in vivo imaging has been used for noninvasive diagnosis of a fungal lung disease (IPA) of humans, an approach with enormous potential for diagnosis of infectious diseases and with potential for clinical translation.
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Sengupta D, Pratx G. Imaging metabolic heterogeneity in cancer. Mol Cancer 2016; 15:4. [PMID: 26739333 PMCID: PMC4704434 DOI: 10.1186/s12943-015-0481-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 12/10/2015] [Indexed: 01/01/2023] Open
Abstract
As our knowledge of cancer metabolism has increased, it has become apparent that cancer metabolic processes are extremely heterogeneous. The reasons behind this heterogeneity include genetic diversity, the existence of multiple and redundant metabolic pathways, altered microenvironmental conditions, and so on. As a result, methods in the clinic and beyond have been developed in order to image and study tumor metabolism in the in vivo and in vitro regimes. Both regimes provide unique advantages and challenges, and may be used to provide a picture of tumor metabolic heterogeneity that is spatially and temporally comprehensive. Taken together, these methods may hold the key to appropriate cancer diagnoses and treatments in the future.
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Affiliation(s)
- Debanti Sengupta
- Stanford University School of Medicine, A226 Building A, 1050 Arastradero Road, Palo Alto, CA, 94304, USA
| | - Guillem Pratx
- Stanford University School of Medicine, A226 Building A, 1050 Arastradero Road, Palo Alto, CA, 94304, USA.
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38
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Shrestha UM, Seo Y, Botvinick EH, Gullberg GT. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration. Phys Med Biol 2015; 60:8275-301. [PMID: 26450115 DOI: 10.1088/0031-9155/60/21/8275] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.
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Affiliation(s)
- Uttam M Shrestha
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA. Structural Biology and Imaging Department, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Shah D, Deleye S, Verhoye M, Staelens S, Van der Linden A. Resting-state functional MRI and [18F]-FDG PET demonstrate differences in neuronal activity between commonly used mouse strains. Neuroimage 2015; 125:571-577. [PMID: 26520769 DOI: 10.1016/j.neuroimage.2015.10.073] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/04/2015] [Accepted: 10/24/2015] [Indexed: 12/13/2022] Open
Abstract
The existence of numerous interesting mouse models of neurological disorders enables the investigation of causal relations between pathological events and the effect of treatment regimes. However, mouse models of a specific neurological disease are often generated using different background strains, which raises the question whether the observed effects are specific to pathology or depend on the used strain. This study used two independent in vivo functional imaging techniques to evaluate whether mouse strain differences exist in functional connectivity (FC) and brain glucose metabolism i.e. indirect measures of neuronal activity. For this purpose, C57BL/6, BALB/C and SJL mice (N=15/group, male) were evaluated using resting-state functional MRI (rsfMRI) and static [18F]-fluorodeoxyglucose Positron Emission Tomography ([18F]-FDG PET). RsfMRI and [18F]-FDG PET data were analyzed with independent component analysis (ICA). FC was quantified by calculating the mean network-specific FC strength and [18F]-FDG uptake was quantified by calculating the mean network-specific standard uptake value corrected for plasma glucose levels and body weight (SUVglu). The ICA results showed spatially similar neurological components in the rsfMRI and [18F]-FDG PET data, suggesting that patterns of metabolic covariance in the mouse brain reflect FC networks. Comparing FC and [18F]-FDG data showed that strain-dependent differences in brain activity exist for several brain networks i.e. the frontal, cingulate, (hypo)thalamus, striatum, and sensorimotor networks. The results of this study have implications for the interpretation of in vivo functional imaging data in mouse models of neurological disorders generated on different background strains.
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Affiliation(s)
- Disha Shah
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium.
| | - Steven Deleye
- Molecular Imaging Center Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
| | - Steven Staelens
- Molecular Imaging Center Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
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Ouyang Y, Judenhofer MS, Walton JH, Marik J, Williams SP, Cherry SR. Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia. J Vis Exp 2015. [PMID: 26437227 DOI: 10.3791/52728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-ᴅ-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.
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Affiliation(s)
- Yu Ouyang
- Department of Biomedical Engineering, University of California, Davis;
| | | | - Jeffrey H Walton
- Department of Biomedical Engineering, University of California, Davis; Nuclear Magnetic Resonance Facility, University of California, Davis
| | | | | | - Simon R Cherry
- Department of Biomedical Engineering, University of California, Davis; Department of Radiology, University of California, Davis
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Machulla HJ. Alzheimer Disease: Approaches to Early Diagnosis and High-Accuracy Imaging. J Nucl Med 2015; 56:1466-7. [DOI: 10.2967/jnumed.115.162891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Imaging technologies and basic considerations for welfare of laboratory rodents. Lab Anim (NY) 2015; 44:97-105. [DOI: 10.1038/laban.665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/11/2014] [Indexed: 02/06/2023]
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Sitti M, Ceylan H, Hu W, Giltinan J, Turan M, Yim S, Diller E. Biomedical Applications of Untethered Mobile Milli/Microrobots. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2015; 103:205-224. [PMID: 27746484 PMCID: PMC5063027 DOI: 10.1109/jproc.2014.2385105] [Citation(s) in RCA: 289] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Untethered robots miniaturized to the length scale of millimeter and below attract growing attention for the prospect of transforming many aspects of health care and bioengineering. As the robot size goes down to the order of a single cell, previously inaccessible body sites would become available for high-resolution in situ and in vivo manipulations. This unprecedented direct access would enable an extensive range of minimally invasive medical operations. Here, we provide a comprehensive review of the current advances in biome dical untethered mobile milli/microrobots. We put a special emphasis on the potential impacts of biomedical microrobots in the near future. Finally, we discuss the existing challenges and emerging concepts associated with designing such a miniaturized robot for operation inside a biological environment for biomedical applications.
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Affiliation(s)
- Metin Sitti
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany, and also are with Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15238 USA
| | - Hakan Ceylan
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Wenqi Hu
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Joshua Giltinan
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany, and also are with Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15238 USA
| | - Mehmet Turan
- Max-Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Sehyuk Yim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Eric Diller
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S3G8, Canada
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Wehrl HF, Sauter AW, Divine MR, Pichler BJ. Combined PET/MR: A Technology Becomes Mature. J Nucl Med 2015; 56:165-8. [DOI: 10.2967/jnumed.114.150318] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Yoo HJ, Lee JS, Lee JM. Integrated whole body MR/PET: where are we? Korean J Radiol 2015; 16:32-49. [PMID: 25598673 PMCID: PMC4296276 DOI: 10.3348/kjr.2015.16.1.32] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/09/2014] [Indexed: 01/16/2023] Open
Abstract
Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.
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Affiliation(s)
- Hye Jin Yoo
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jae Sung Lee
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea
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