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Hervier E, Glessgen C, Nkoulou R, François Deux J, Vallee JP, Adamopoulos D. Hybrid PET/MR in Cardiac Imaging. Magn Reson Imaging Clin N Am 2023; 31:613-624. [PMID: 37741645 DOI: 10.1016/j.mric.2023.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/25/2023]
Abstract
In the last few years, technological advances in MR imaging, PET detectors, and attenuation correction algorithms have allowed the creation of truly integrated PET/MR imaging systems, for both clinical and research applications. These machines allow a comprehensive investigation of cardiovascular diseases, by offering a wide variety of detailed anatomical and functional data in combination. Despite significant pathophysiologic mechanisms being clarified by this new data, its clinical relevance and prognostic significance have not been demonstrated yet.
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Affiliation(s)
- Elsa Hervier
- Diagnostics Department, Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland
| | - Carl Glessgen
- Diagnostics Department, Radiology, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland
| | - René Nkoulou
- Diagnostics Department, Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland
| | - Jean François Deux
- Diagnostics Department, Radiology, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland
| | - Jean-Paul Vallee
- Diagnostics Department, Radiology, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland
| | - Dionysios Adamopoulos
- Department of Medical Specialties, Cardiology, Geneva University Hospital, Gabrielle-Perret-Gentil 4 street, 1205, Geneva, Switzerland.
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2
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Wilk B, Smailovic H, Wisenberg G, Sykes J, Butler J, Kovacs M, Thiessen JD, Prato FS. Tracking the progress of inflammation with PET/MRI in a canine model of myocardial infarction. J Nucl Cardiol 2022; 29:1315-1325. [PMID: 33462785 DOI: 10.1007/s12350-020-02487-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/28/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND Following myocardial infarction, tissue undergoes pathophysiological changes involving inflammation and scar tissue formation. However, little is known about the pathophysiology and prognostic significance of any corresponding changes in remote myocardium. The aim of this study was to investigate the potential application of a combined constant infusion of 18F-FDG and Gd-DTPA to quantitate inflammation and extracellular volume (ECV) from 3 to 40 days after myocardial infarction. METHODS Eight canine subjects were imaged at multiple time points following induction of an MI with a 60-minute concurrent constant infusion of Gd-DTPA and 18F-FDG using a hybrid PET/MRI scanner. RESULTS There was a significant increase in ECV in remote myocardium on day 14 post-MI (P = .034) and day 21 (P = .021) compared to the baseline. ECV was significantly elevated in the infarcted myocardium compared to remote myocardium at all time points post-MI (days 3, 7, 14, 21, and 40) (P < .001) while glucose uptake was also increased within the infarct on days 3, 7, 14, and 21 but not 40. CONCLUSIONS The significant increase in ECV in remote tissue may be due to an ongoing inflammatory process in the early weeks post-infarct.
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Affiliation(s)
- B Wilk
- Lawson Health Research Institute, London, Canada.
- Department of Medical Biophysics, Western University, London, Canada.
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada.
| | - H Smailovic
- Lawson Health Research Institute, London, Canada
- Department of Medical Imaging, Western University, London, Canada
| | - G Wisenberg
- Lawson Health Research Institute, London, Canada
- MyHealth Centre, Arva, Canada
| | - J Sykes
- Lawson Health Research Institute, London, Canada
| | - J Butler
- Lawson Health Research Institute, London, Canada
| | - M Kovacs
- Lawson Health Research Institute, London, Canada
- Department of Medical Biophysics, Western University, London, Canada
- Department of Medical Imaging, Western University, London, Canada
| | - J D Thiessen
- Lawson Health Research Institute, London, Canada
- Department of Medical Biophysics, Western University, London, Canada
- Department of Medical Imaging, Western University, London, Canada
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada
| | - F S Prato
- Lawson Health Research Institute, London, Canada
- Department of Medical Biophysics, Western University, London, Canada
- Department of Medical Imaging, Western University, London, Canada
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada
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3
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Elwazir MY, Bois JP, Chareonthaitawee P. Utilization of cardiac imaging in sarcoidosis. Expert Rev Cardiovasc Ther 2022; 20:253-266. [DOI: 10.1080/14779072.2022.2069560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Mohamed Y. Elwazir
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Cardiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - John P. Bois
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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Bogdanovic B, Solari EL, Villagran Asiares A, McIntosh L, van Marwick S, Schachoff S, Nekolla SG. PET/MR Technology: Advancement and Challenges. Semin Nucl Med 2021; 52:340-355. [PMID: 34969520 DOI: 10.1053/j.semnuclmed.2021.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 01/07/2023]
Abstract
When this article was written, it coincided with the 11th anniversary of the installation of our PET/MR device in Munich. In fact, this was the first fully integrated device to be in clinical use. During this time, we have observed many interesting behaviors, to put it kindly. However, it is more critical that in this process, our understanding of the system also improved - including the advantages and limitations from a technical, logistical, and medical perspective. The last decade of PET/MRI research has certainly been characterized by most sites looking for a "key application." There were many ideas in this context and before and after the devices became available, some of which were based on the earlier work with integrating data from single devices. These involved validating classical PET methods with MRI (eg, perfusion or oncology diagnostics). More important, however, were the scenarios where intermodal synergies could be expected. In this review, we look back on this decade-long journey, at the challenges overcome and those still to come.
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Affiliation(s)
- Borjana Bogdanovic
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Esteban Lucas Solari
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Alberto Villagran Asiares
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Lachlan McIntosh
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Sandra van Marwick
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sylvia Schachoff
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Stephan G Nekolla
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.
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5
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Robson PM, Vergani V, Benkert T, Trivieri MG, Karakatsanis NA, Abgral R, Dweck MR, Moreno PR, Kovacic JC, Block KT, Fayad ZA. Assessing the qualitative and quantitative impacts of simple two-class vs multiple tissue-class MR-based attenuation correction for cardiac PET/MR. J Nucl Cardiol 2021; 28:2194-2204. [PMID: 31898004 PMCID: PMC7329599 DOI: 10.1007/s12350-019-02002-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hybrid PET/MR imaging has significant potential in cardiology due to its combination of molecular PET imaging and cardiac MR. Multi-tissue-class MR-based attenuation correction (MRAC) is necessary for accurate PET quantification. Moreover, for thoracic PET imaging, respiration is known to lead to misalignments of MRAC and PET data that result in PET artifacts. These factors can be addressed by using multi-echo MR for tissue segmentation and motion-robust or motion-gated acquisitions. However, the combination of these strategies is not routinely available and can be prone to errors. In this study, we examine the qualitative and quantitative impacts of multi-class MRAC compared to a more widely available simple two-class MRAC for cardiac PET/MR. METHODS AND RESULTS In a cohort of patients with cardiac sarcoidosis, we acquired MRAC data using multi-echo radial gradient-echo MR imaging. Water-fat separation was used to produce attenuation maps with up to 4 tissue classes including water-based soft tissue, fat, lung, and background air. Simultaneously acquired 18F-fluorodeoxyglucose PET data were subsequently reconstructed using each attenuation map separately. PET uptake values were measured in the myocardium and compared between different PET images. The inclusion of lung and subcutaneous fat in the MRAC maps significantly affected the quantification of 18F-fluorodeoxyglucose activity in the myocardium but only moderately altered the appearance of the PET image without introduction of image artifacts. CONCLUSION Optimal MRAC for cardiac PET/MR applications should include segmentation of all tissues in combination with compensation for the respiratory-related motion of the heart. Simple two-class MRAC is adequate for qualitative clinical assessment.
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Affiliation(s)
- Philip M Robson
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA.
| | - Vittoria Vergani
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Cardiothoracic and Vascular Department, Vita-Salute University and San Raffaele Hospital, Milan, Italy
| | - Thomas Benkert
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Maria Giovanna Trivieri
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Nicolas A Karakatsanis
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Division of Radiopharmaceutical Sciences, Department of Radiology, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Ronan Abgral
- Department of Nuclear Medicine, University Hospital of Brest, European University of Brittany, EA3878 GETBO, Brest, France
| | - Marc R Dweck
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Pedro R Moreno
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Jason C Kovacic
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
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Lennie E, Tsoumpas C, Sourbron S. Multimodal phantoms for clinical PET/MRI. EJNMMI Phys 2021; 8:62. [PMID: 34436671 PMCID: PMC8390737 DOI: 10.1186/s40658-021-00408-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022] Open
Abstract
Phantoms are commonly used throughout medical imaging and medical physics for a multitude of applications, the designs of which vary between modalities and clinical or research requirements. Within positron emission tomography (PET) and nuclear medicine, phantoms have a well-established role in the validation of imaging protocols so as to reduce the administration of radioisotope to volunteers. Similarly, phantoms are used within magnetic resonance imaging (MRI) to perform quality assurance on clinical scanners, and gel-based phantoms have a longstanding use within the MRI research community as tissue equivalent phantoms. In recent years, combined PET/MRI scanners for simultaneous acquisition have entered both research and clinical use. This review explores the designs and applications of phantom work within the field of simultaneous acquisition PET/MRI as published over the period of a decade. Common themes in the design, manufacture and materials used within phantoms are identified and the solutions they provided to research in PET/MRI are summarised. Finally, the challenges remaining in creating multimodal phantoms for use with simultaneous acquisition PET/MRI are discussed. No phantoms currently exist commercially that have been designed and optimised for simultaneous PET/MRI acquisition. Subsequently, commercially available PET and nuclear medicine phantoms are often utilised, with CT-based attenuation maps substituted for MR-based attenuation maps due to the lack of MR visibility in phantom housing. Tissue equivalent and anthropomorphic phantoms are often developed by research groups in-house and provide customisable alternatives to overcome barriers such as MR-based attenuation correction, or to address specific areas of study such as motion correction. Further work to characterise materials and manufacture methods used in phantom design would facilitate the ability to reproduce phantoms across sites.
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Affiliation(s)
- Eve Lennie
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Charalampos Tsoumpas
- Biomedical Imaging Science Department, University of Leeds, Leeds, UK
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Steven Sourbron
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
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Brancato V, Borrelli P, Alfano V, Picardi M, Mascalchi M, Nicolai E, Salvatore M, Aiello M. The impact of MR-based attenuation correction in spinal cord FDG-PET/MR imaging for neurological studies. Med Phys 2021; 48:5924-5934. [PMID: 34369590 PMCID: PMC9293017 DOI: 10.1002/mp.15149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 05/30/2021] [Accepted: 07/24/2021] [Indexed: 11/21/2022] Open
Abstract
Purpose Positron emission tomography (PET) attenuation correction (AC) in positron emission tomography‐magnetic resonance (PET/MR) scanners constitutes a critical and barely explored issue in spinal cord investigation, mainly due to the limitations in accounting for highly attenuating bone structures which surround the spinal canal. Our study aims at evaluating the clinical suitability of MR‐driven AC (MRAC) for 18‐fluorodeoxy‐glucose positron emission tomography (18F‐FDG‐PET) in spinal cord. Methods Thirty‐six patients, undergoing positron emission tomography‐computed tomography (PET/CT) and PET/MR in the same session for oncological examination, were retrospectively analyzed. For each patient, raw PET data from PET/MR scanner were reconstructed with 4‐ and 5‐class MRAC maps, generated by hybrid PET/MR system (PET_MRAC4 and PET_MRAC5, respectively, where PET_MRAC is PET images reconstructed using MR‐based attenuation correction map), and an AC map derived from CT data after a custom co‐registration pipeline (PET_rCTAC, where PET_rCTAC is PET images reconstructed using CT‐based attenuation correction map), which served as reference. Mean PET standardized uptake values (SUVm) were extracted from the three reconstructed PET images by regions of interest (ROIs) identified on T2‐weighted MRI, in the spinal cord, lumbar cerebrospinal fluid (CSF), and vertebral marrow at five levels (C2, C5, T6, T12, and L3). SUVm values from PET_MRAC4 and PET_MRAC5 were compared with each other and with the reference by means of paired t‐test, and correlated using Pearson's correlation (r) to assess their consistency. Cohen's d was calculated to assess the magnitude of differences between PET images. Results SUVmvalues from PET_MRAC4 were lower than those from PET_MRAC5 in almost all analyzed ROIs, with a mean difference ranging from 0.03 to 0.26 (statistically significant in the vertebral marrow at C2 and C5, spinal cord at T6 and T2, and CSF at L3). This was also confirmed by the effect size, with highest values at low spinal levels (d = 0.45 at T12 in spinal cord, d = 0.95 at L3 in CSF). SUVm values from PET_MRAC4 and PET_MRAC5 showed a very good correlation (0.81 < r < 0.97, p < 0.05) in all spinal ROIs. Underestimation of SUVm between PET_MRAC4 and PET_rCTAC was observed at each level, with a mean difference ranging from 0.02 to 0.32 (statistically significant in the vertebral marrow at C2 and T6, and CSF at L3). Although PET_MRAC5 underestimates PET_rCTAC (mean difference ranging from 0.02 to 0.3), an overall decrease in effect size could be observed for PET_MRAC5, mainly at lower spinal levels (T12, L3). SUVm from both PET_MRAC4 and PET_MRAC5 methods showed r value from good to very good with respect to PET_rCTAC (0.67 < r < 0.9 and 0.73 < r < 0.94, p < 0.05, respectively). Conclusions Our results showed that neglecting bones in AC can underestimate the FDG uptake measurement of the spinal cord. The inclusion of bones in MRAC is far from negligible and improves the AC in spinal cord, mainly at low spinal levels. Therefore, care must be taken in the spinal canal region, and the use of AC map reconstruction methods accounting for bone structures could be beneficial.
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Affiliation(s)
| | | | | | - Marco Picardi
- Department of Clinical Medicine and Surgery, Federico II University Medical School, Naples, Italy
| | - Mario Mascalchi
- «Mario Serio» Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
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Mayer J, Jin Y, Wurster TH, Makowski MR, Kolbitsch C. Evaluation of synergistic image registration for motion-corrected coronary NaF-PET-MR. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200202. [PMID: 33966463 PMCID: PMC8107649 DOI: 10.1098/rsta.2020.0202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Coronary artery disease (CAD) is caused by the formation of plaques in the coronary arteries and is one of the most common cardiovascular diseases. NaF-PET can be used to assess plaque composition, which could be important for therapy planning. One of the main challenges of NaF-PET is cardiac and respiratory motion which can strongly impair diagnostic accuracy. In this study, we investigated the use of a synergistic image registration approach which combined motion-resolved MR and PET data to estimate cardiac and respiratory motion. This motion estimation could then be used to improve the NaF-PET image quality. The approach was evaluated with numerical simulations and in vivo scans of patients suffering from CAD. In numerical simulations, it was shown, that combining MR and PET information can improve the accuracy of motion estimation by more than 15%. For the in vivo scans, the synergistic image registration led to an improvement in uptake visualization. This is the first study to assess the benefit of combining MR and NaF-PET for cardiac and respiratory motion estimation. Further patient evaluation is required to fully evaluate the potential of this approach. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 1'.
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Affiliation(s)
- Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Yining Jin
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Thomas-Heinrich Wurster
- Klinik für Kardiologie, Charité Campus Benjamin Franklin, Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
| | - Marcus R. Makowski
- Department of Radiology, Charité, Universitätsmedizin Berlin, Berlin, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
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9
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Abstract
Attenuation correction has been one of the main methodological challenges in the integrated positron emission tomography and magnetic resonance imaging (PET/MRI) field. As standard transmission or computed tomography approaches are not available in integrated PET/MRI scanners, MR-based attenuation correction approaches had to be developed. Aspects that have to be considered for implementing accurate methods include the need to account for attenuation in bone tissue, normal and pathological lung and the MR hardware present in the PET field-of-view, to reduce the impact of subject motion, to minimize truncation and susceptibility artifacts, and to address issues related to the data acquisition and processing both on the PET and MRI sides. The standard MR-based attenuation correction techniques implemented by the PET/MRI equipment manufacturers and their impact on clinical and research PET data interpretation and quantification are first discussed. Next, the more advanced methods, including the latest generation deep learning-based approaches that have been proposed for further minimizing the attenuation correction related bias are described. Finally, a future perspective focused on the needed developments in the field is given.
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Affiliation(s)
- Ciprian Catana
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States of America
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10
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Wilk B, Wisenberg G, Dharmakumar R, Thiessen JD, Goldhawk DE, Prato FS. Hybrid PET/MR imaging in myocardial inflammation post-myocardial infarction. J Nucl Cardiol 2020; 27:2083-2099. [PMID: 31797321 PMCID: PMC7391987 DOI: 10.1007/s12350-019-01973-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 01/24/2023]
Abstract
Hybrid PET/MR imaging is an emerging imaging modality combining positron emission tomography (PET) and magnetic resonance imaging (MRI) in the same system. Since the introduction of clinical PET/MRI in 2011, it has had some impact (e.g., imaging the components of inflammation in myocardial infarction), but its role could be much greater. Many opportunities remain unexplored and will be highlighted in this review. The inflammatory process post-myocardial infarction has many facets at a cellular level which may affect the outcome of the patient, specifically the effects on adverse left ventricular remodeling, and ultimately prognosis. The goal of inflammation imaging is to track the process non-invasively and quantitatively to determine the best therapeutic options for intervention and to monitor those therapies. While PET and MRI, acquired separately, can image aspects of inflammation, hybrid PET/MRI has the potential to advance imaging of myocardial inflammation. This review contains a description of hybrid PET/MRI, its application to inflammation imaging in myocardial infarction and the challenges, constraints, and opportunities in designing data collection protocols. Finally, this review explores opportunities in PET/MRI: improved registration, partial volume correction, machine learning, new approaches in the development of PET and MRI pulse sequences, and the use of novel injection strategies.
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Affiliation(s)
- B Wilk
- Department of Medical Imaging, Western University, London, Canada.
- Lawson Health Research Institute, London, Canada.
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada.
| | - G Wisenberg
- Department of Medical Imaging, Western University, London, Canada
- MyHealth Centre, Arva, Canada
| | - R Dharmakumar
- Biomedical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - J D Thiessen
- Department of Medical Imaging, Western University, London, Canada
- Lawson Health Research Institute, London, Canada
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada
| | - D E Goldhawk
- Department of Medical Imaging, Western University, London, Canada
- Lawson Health Research Institute, London, Canada
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada
| | - F S Prato
- Department of Medical Imaging, Western University, London, Canada
- Lawson Health Research Institute, London, Canada
- Collaborative Graduate Program in Molecular Imaging, Western University, London, Canada
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11
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Abstract
Cardiac PET/MR imaging is an integrated imaging approach that requires less radiation than PET/computed tomography and combines the high spatial resolution and morphologic data from MR imaging with the physiologic information from PET. This hybrid approach has the potential to improve the diagnostic and prognostic evaluation of several cardiovascular conditions, such as ischemic heart disease, infiltrative diseases such as sarcoidosis, acute and chronic myocarditis, and cardiac masses. Herein, the authors discuss the strengths of PET and MR imaging in several cardiovascular conditions; the challenges and potential; and the current data on the application of this powerful hybrid imaging modality.
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Affiliation(s)
- Rhanderson Cardoso
- Division of Cardiology, Johns Hopkins Hospital, 600 North Wolfe Street, Blalock 547, Baltimore, MD 21287, USA
| | - Thorsten M Leucker
- Division of Cardiology, Johns Hopkins Hospital, 600 North Wolfe Street, Blalock 547, Baltimore, MD 21287, USA.
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12
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Karakatsanis NA, Abgral R, Trivieri MG, Dweck MR, Robson PM, Calcagno C, Boeykens G, Senders ML, Mulder WJM, Tsoumpas C, Fayad ZA. Hybrid PET- and MR-driven attenuation correction for enhanced 18F-NaF and 18F-FDG quantification in cardiovascular PET/MR imaging. J Nucl Cardiol 2020; 27:1126-1141. [PMID: 31667675 PMCID: PMC7190435 DOI: 10.1007/s12350-019-01928-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 10/02/2019] [Accepted: 10/02/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND The standard MR Dixon-based attenuation correction (AC) method in positron emission tomography/magnetic resonance (PET/MR) imaging segments only the air, lung, fat and soft-tissues (4-class), thus neglecting the highly attenuating bone tissues and affecting quantification in bones and adjacent vessels. We sought to address this limitation by utilizing the distinctively high bone uptake rate constant Ki expected from 18F-Sodium Fluoride (18F-NaF) to segment bones from PET data and support 5-class hybrid PET/MR-driven AC for 18F-NaF and 18F-Fluorodeoxyglucose (18F-FDG) PET/MR cardiovascular imaging. METHODS We introduce 5-class Ki/MR-AC for (i) 18F-NaF studies where the bones are segmented from Patlak Ki images and added as the 5th tissue class to the MR Dixon 4-class AC map. Furthermore, we propose two alternative dual-tracer protocols to permit 5-class Ki/MR-AC for (ii) 18F-FDG-only data, with a streamlined simultaneous administration of 18F-FDG and 18F-NaF at 4:1 ratio (R4:1), or (iii) for 18F-FDG-only or both 18F-FDG and 18F-NaF dual-tracer data, by administering 18F-NaF 90 minutes after an equal 18F-FDG dosage (R1:1). The Ki-driven bone segmentation was validated against computed tomography (CT)-based segmentation in rabbits, followed by PET/MR validation on 108 vertebral bone and carotid wall regions in 16 human volunteers with and without prior indication of carotid atherosclerosis disease (CAD). RESULTS In rabbits, we observed similar (< 1.2% mean difference) vertebral bone 18F-NaF SUVmean scores when applying 5-class AC with Ki-segmented bone (5-class Ki/CT-AC) vs CT-segmented bone (5-class CT-AC) tissue. Considering the PET data corrected with continuous CT-AC maps as gold-standard, the percentage SUVmean bias was reduced by 17.6% (18F-NaF) and 15.4% (R4:1) with 5-class Ki/CT-AC vs 4-class CT-AC. In humans without prior CAD indication, we reported 17.7% and 20% higher 18F-NaF target-to-background ratio (TBR) at carotid bifurcations wall and vertebral bones, respectively, with 5- vs 4-class AC. In the R4:1 human cohort, the mean 18F-FDG:18F-NaF TBR increased by 12.2% at carotid bifurcations wall and 19.9% at vertebral bones. For the R1:1 cohort of subjects without CAD indication, mean TBR increased by 15.3% (18F-FDG) and 15.5% (18F-NaF) at carotid bifurcations and 21.6% (18F-FDG) and 22.5% (18F-NaF) at vertebral bones. Similar TBR enhancements were observed when applying the proposed AC method to human subjects with prior CAD indication. CONCLUSIONS Ki-driven bone segmentation and 5-class hybrid PET/MR-driven AC is feasible and can significantly enhance 18F-NaF and 18F-FDG contrast and quantification in bone tissues and carotid walls.
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Affiliation(s)
- Nicolas A Karakatsanis
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA.
- Department of Radiology, Weill Cornell Medical College, Cornell University, 515 E 71st Street, S-120, New York, NY, 10021, USA.
| | - Ronan Abgral
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- Department of Nuclear Medicine, University Hospital of Brest, Brest, France
| | - Maria Giovanna Trivieri
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
| | - Marc R Dweck
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- British Heart Foundation, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Philip M Robson
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
| | - Claudia Calcagno
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
| | - Gilles Boeykens
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands
| | - Max L Senders
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands
| | - Willem J M Mulder
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands
| | - Charalampos Tsoumpas
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
- Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Zahi A Fayad
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave, New York, NY, 10029, USA
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13
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Lassen ML, Slomka PJ. PET-derived bone information from 18F-sodium fluoride: A perfect match for whole-body PET/MR attenuation correction? J Nucl Cardiol 2020; 27:1142-1144. [PMID: 31897993 DOI: 10.1007/s12350-019-01994-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 11/25/2022]
Affiliation(s)
- Martin Lyngby Lassen
- Artificial Intelligence in Medicine Program, Cedars-Sinai Medical Center, 8700 Beverly Blvd. Ste. A047, Los Angeles, CA, 90048, USA.
| | - Piotr J Slomka
- Artificial Intelligence in Medicine Program, Cedars-Sinai Medical Center, 8700 Beverly Blvd. Ste. A047, Los Angeles, CA, 90048, USA
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14
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Elwazir MY, Bois JP, Abou Ezzeddine OF, Chareonthaitawee P. Imaging and Quantification of Cardiac Sarcoidosis. Semin Nucl Med 2020; 50:283-294. [PMID: 32540026 DOI: 10.1053/j.semnuclmed.2020.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiac sarcoidosis (CS) refers to the increasingly recognized cardiac involvement of an incompletely understood systemic disease entity-sarcoidosis. Endomyocardial biopsy can provide definitive diagnosis but is limited by its invasiveness and poor sensitivity. In the absence of a reliable gold standard, a combination of clinical, electrocardiographic, imaging, and histologic criteria are relied upon to provide probabilistic diagnosis. Within the last few years, societal documents have included advanced cardiovascular imaging modalities, 18F-FDG-PET/CT and cardiac magnetic resonance in their diagnostic algorithms. The current article provides a review of the imaging modalities used for screening and detection of CS, highlighting the principal findings of each with a specific focus on quantification, whenever applicable, and concluding with a proposed approach to the imaging of patients with suspected CS.
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Affiliation(s)
- Mohamed Y Elwazir
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN; Department of Cardiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - John P Bois
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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15
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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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16
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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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17
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Rischpler C, Siebermair J, Kessler L, Quick HH, Umutlu L, Rassaf T, Antoch G, Herrmann K, Nensa F. Cardiac PET/MRI: Current Clinical Status and Future Perspectives. Semin Nucl Med 2020; 50:260-269. [PMID: 32284112 DOI: 10.1053/j.semnuclmed.2020.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Combined PET/MRI has now been in clinical routine for almost 10 years. Since then, it has not only had to face validation, comparison and research questions, it has also been increasingly used in clinical routine. A number of cardiovascular applications have become established here, whereby viability imaging and assessment of inflammatory and infiltrative processes in the heart are to be emphasized. However, further interesting applications are expected in the near future. This review summarizes the most important clinical applications on the one hand and mentions interesting areas of application in research on the other.
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Affiliation(s)
- Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Johannes Siebermair
- Department of Cardiology and Vascular Medicine, University Hospital Essen, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany
| | - Lukas Kessler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany; Erwin L Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Tienush Rassaf
- Department of Cardiology and Vascular Medicine, University Hospital Essen, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Felix Nensa
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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18
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Lassen ML, Rasul S, Beitzke D, Stelzmüller ME, Cal-Gonzalez J, Hacker M, Beyer T. Assessment of attenuation correction for myocardial PET imaging using combined PET/MRI. J Nucl Cardiol 2019; 26:1107-1118. [PMID: 29168158 PMCID: PMC6660490 DOI: 10.1007/s12350-017-1118-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/18/2017] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To evaluate the frequency of artifacts in MR-based attenuation correction (AC) maps and their impact on the quantitative accuracy of PET-based flow and metabolism measurements in a cohort of consecutive heart failure patients undergoing combined PET/MR imaging. METHODS Myocardial viability studies were performed in 20 patients following a dual-tracer protocol involving the assessment of myocardial perfusion (13N-NH3: 813 ± 86 MBq) and metabolism (18F-FDG: 335 ± 38 MBq). All acquisitions were performed using a fully-integrated PET/MR system, with standard DIXON-attenuation correction (DIXON-AC) mapping for each PET scan. All AC maps were examined for spatial misalignment with the emission data, total lung volume, susceptibility artifacts, and tissue inversion (TI). Misalignment and susceptibility artifacts were corrected using rigid co-registration and retrospective filling of the susceptibility-induced gaps, respectively. The effects of the AC artifacts were evaluated by relative difference measures and perceived changes in clinical interpretations. RESULTS Average respiratory misalignment of (7 ± 4) mm of the PET-emission data and the AC maps was observed in 18 (90%) patients. Substantial changes in the lung volumes of the AC maps were observed in the test-retest analysis (ratio: 1.0 ± 0.2, range: 0.8-1.4). Susceptibility artifacts were observed in 10 (50%) patients, while six (30%) patients had TI artifacts. Average differences of 14 ± 10% were observed for PET images reconstructed with the artifactual AC maps. The combined artifact effects caused false-positive findings in three (15%) patients. CONCLUSION Standard DIXON-AC maps must be examined carefully for artifacts and misalignment effects prior to AC correction of cardiac PET/MRI studies in order to avoid misinterpretation of biased perfusion and metabolism readings from the PET data.
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Affiliation(s)
- Martin Lyngby Lassen
- QIMP Group, Center for Medical Physics and Biomedical Engineering, General Hospital Vienna, Medical University of Vienna, 1090, Vienna, Austria.
| | - Sazan Rasul
- Division of Nuclear Medicine, Department of Biomedical Engineering and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Dietrich Beitzke
- Division of Cardiovascular and Interventional Radiology, Department of Biomedical Engineering and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | | | - Jacobo Cal-Gonzalez
- QIMP Group, Center for Medical Physics and Biomedical Engineering, General Hospital Vienna, Medical University of Vienna, 1090, Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Engineering and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Beyer
- QIMP Group, Center for Medical Physics and Biomedical Engineering, General Hospital Vienna, Medical University of Vienna, 1090, Vienna, Austria
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19
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20
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Lindemann ME, Nensa F, Quick HH. Impact of improved attenuation correction on 18F-FDG PET/MR hybrid imaging of the heart. PLoS One 2019; 14:e0214095. [PMID: 30908507 PMCID: PMC6433217 DOI: 10.1371/journal.pone.0214095] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/06/2019] [Indexed: 01/16/2023] Open
Abstract
Purpose The aim of this study was to evaluate and quantify the effect of improved attenuation correction (AC) including bone segmentation and truncation correction on 18F-Fluordesoxyglucose cardiac positron emission tomography/magnetic resonance (PET/MR) imaging. Methods PET data of 32 cardiac PET/MR datasets were reconstructed with three different AC-maps (1. Dixon-VIBE only, 2. HUGE truncation correction and bone segmentation, 3. MLAA). The Dixon-VIBE AC-maps served as reference of reconstructed PET data. 17-segment short-axis polar plots of the left ventricle were analyzed regarding the impact of each of the three AC methods on PET quantification in cardiac PET/MR imaging. Non-AC PET images were segmented to specify the amount of truncation in the Dixon-VIBE AC-map serving as a reference. All AC-maps were evaluated for artifacts. Results Using HUGE + bone AC results in a homogeneous gain of ca. 6% and for MLAA 8% of PET signal distribution across the myocardium of the left ventricle over all patients compared to Dixon-VIBE AC only. Maximal relative differences up to 18% were observed in segment 17 (apex). The body volume truncation of -12.7 ± 7.1% compared to the segmented non-AC PET images using the Dixon-VIBE AC method was reduced to -1.9 ± 3.9% using HUGE and 7.8 ± 8.3% using MLAA. In each patient, a systematic overestimation in AC-map volume was observed when applying MLAA. Quantitative impact of artifacts showed regional differences up to 6% within single segments of the myocardium. Conclusions Improved AC including bone segmentation and truncation correction in cardiac PET/MR imaging is important to ensure best possible diagnostic quality and PET quantification. The results exhibited an overestimation of AC-map volume using MLAA, while HUGE resulted in a more realistic body contouring. Incorporation of bone segmentation into the Dixon-VIBE AC-map resulted in homogeneous gain in PET signal distribution across the myocardium. The majority of observed AC-map artifacts did not significantly affect the quantitative assessment of the myocardium.
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Affiliation(s)
- Maike E. Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- * E-mail:
| | - Felix Nensa
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Harald H. Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
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21
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Rischpler C, Nekolla SG, Heusch G, Umutlu L, Rassaf T, Heusch P, Herrmann K, Nensa F. Cardiac PET/MRI-an update. Eur J Hybrid Imaging 2019; 3:2. [PMID: 34191143 PMCID: PMC8212244 DOI: 10.1186/s41824-018-0050-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022] Open
Abstract
It is now about 8 years since the first whole-body integrated PET/MRI has been installed. First, reports on technical characteristics and system performance were published. Early after, reports on the first use of PET/MRI in oncological patients were released. Interestingly, the first article on the application in cardiology was a review article, which was published before the first original article was put out. Since then, researchers have gained a lot experience with the PET/MRI in various cardiovascular diseases and an increasing number on auspicious indications is appearing. In this review article, we give an overview on technical updates within these last years with potential impact on cardiac imaging and summarize those scenarios where PET/MRI plays a pivotal role in cardiovascular medicine.
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Affiliation(s)
- C Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - S G Nekolla
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, 81675, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart alliance, Munich, Germany
| | - G Heusch
- Institute for Pathophysiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - L Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - T Rassaf
- Department of Cardiology and Vascular Medicine, University Hospital Essen, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany
| | - P Heusch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - K Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - F Nensa
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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22
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Munoz C, Kunze KP, Neji R, Vitadello T, Rischpler C, Botnar RM, Nekolla SG, Prieto C. Motion-corrected whole-heart PET-MR for the simultaneous visualisation of coronary artery integrity and myocardial viability: an initial clinical validation. Eur J Nucl Med Mol Imaging 2018; 45:1975-1986. [PMID: 29754161 PMCID: PMC6132558 DOI: 10.1007/s00259-018-4047-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/02/2018] [Indexed: 01/08/2023]
Abstract
PURPOSE Cardiac PET-MR has shown potential for the comprehensive assessment of coronary heart disease. However, image degradation due to physiological motion remains a challenge that could hinder the adoption of this technology in clinical practice. The purpose of this study was to validate a recently proposed respiratory motion-corrected PET-MR framework for the simultaneous visualisation of myocardial viability (18F-FDG PET) and coronary artery anatomy (coronary MR angiography, CMRA) in patients with chronic total occlusion (CTO). METHODS A cohort of 14 patients was scanned with the proposed PET-CMRA framework. PET and CMRA images were reconstructed with and without the proposed motion correction approach for comparison purposes. Metrics of image quality including visible vessel length and sharpness were obtained for CMRA for both the right and left anterior descending coronary arteries (RCA, LAD), and relative increase in 18F-FDG PET signal after motion correction for standard 17-segment polar maps was computed. Resulting coronary anatomy by CMRA and myocardial integrity by PET were visually compared against X-ray angiography and conventional Late Gadolinium Enhancement (LGE) MRI, respectively. RESULTS Motion correction increased CMRA visible vessel length by 49.9% and 32.6% (RCA, LAD) and vessel sharpness by 12.3% and 18.9% (RCA, LAD) on average compared to uncorrected images. Coronary lumen delineation on motion-corrected CMRA images was in good agreement with X-ray angiography findings. For PET, motion correction resulted in an average 8% increase in 18F-FDG signal in the inferior and inferolateral segments of the myocardial wall. An improved delineation of myocardial viability defects and reduced noise in the 18F-FDG PET images was observed, improving correspondence to subendocardial LGE-MRI findings compared to uncorrected images. CONCLUSION The feasibility of the PET-CMRA framework for simultaneous cardiac PET-MR imaging in a short and predictable scan time (~11 min) has been demonstrated in 14 patients with CTO. Motion correction increased visible length and sharpness of the coronary arteries by CMRA, and improved delineation of the myocardium by 18F-FDG PET, resulting in good agreement with X-ray angiography and LGE-MRI.
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Affiliation(s)
- Camila Munoz
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK.
| | - Karl P Kunze
- Nuklearmedizinische Klinik und Poliklinik, Technische Universität München, Munich, Germany
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK
- MR Research Collaborations, Siemens Healthcare, Frimley, UK
| | - Teresa Vitadello
- Nuklearmedizinische Klinik und Poliklinik, Technische Universität München, Munich, Germany
| | - Christoph Rischpler
- Nuklearmedizinische Klinik und Poliklinik, Technische Universität München, Munich, Germany
| | - René M Botnar
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK
- Escuela de Ingenieria, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Stephan G Nekolla
- Nuklearmedizinische Klinik und Poliklinik, Technische Universität München, Munich, Germany
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | - Claudia Prieto
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK
- Escuela de Ingenieria, Pontificia Universidad Catolica de Chile, Santiago, Chile
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23
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Nazir MS, Ismail TF, Reyes E, Chiribiri A, Kaufmann PA, Plein S. Hybrid positron emission tomography-magnetic resonance of the heart: current state of the art and future applications. Eur Heart J Cardiovasc Imaging 2018; 19:962-974. [PMID: 30010838 PMCID: PMC6102801 DOI: 10.1093/ehjci/jey090] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/11/2018] [Accepted: 06/12/2018] [Indexed: 02/07/2023] Open
Abstract
Hybrid positron emission tomography-magnetic resonance (PET-MR) imaging is a novel imaging modality with emerging applications for cardiovascular disease. PET-MR aims to combine the high-spatial resolution morphological and functional assessment afforded by magnetic resonance imaging (MRI) with the ability of positron emission tomography (PET) for quantification of metabolism, perfusion, and inflammation. The fusion of these two modalities into a single imaging platform not only represents an opportunity to acquire complementary information from a single scan, but also allows motion correction for PET with reduction in ionising radiation. This article presents a brief overview of PET-MR technology followed by a review of the published literature on the clinical cardio-vascular applications of PET and MRI performed separately and with hybrid PET-MR.
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Affiliation(s)
- Muhummad Sohaib Nazir
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, UK
| | - Tevfik F Ismail
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, UK
| | - Eliana Reyes
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, UK
| | - Amedeo Chiribiri
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, UK
| | - Philipp A Kaufmann
- Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, Zurich, Switzerland
| | - Sven Plein
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, Westminster Bridge Road, London, UK
- Leeds Institute of Cardiovascular and Metabolic Medicine, LIGHT Laboratories, Clarendon Way, University of Leeds, Leeds, UK
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24
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Masuda A, Nemoto A, Takeishi Y. Technical aspects of cardiac PET/MRI. J Nucl Cardiol 2018; 25:1023-1028. [PMID: 29468469 DOI: 10.1007/s12350-018-1237-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/24/2018] [Indexed: 11/24/2022]
Abstract
PET/MRI is a novel modality that enables to combine PET and MR images, and has significant potential to evaluate various cardiac diseases through the combination of PET molecular imaging and MRI functional imaging. Precise management of technical issues, however, is necessary for cardiac PET/MRI. This article describes several technical points, including patient preparation, MR attenuation correction, parallel acquisition of PET with MRI, clinical aspects, and image quality control.
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Affiliation(s)
- Atsuro Masuda
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima, 960-1295, Japan.
| | - Ayaka Nemoto
- Advanced Clinical Research Center, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima, 960-1295, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima-shi, Fukushima, 960-1295, Japan
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AlJaroudi WA, Hage FG. Review of cardiovascular imaging in the Journal of Nuclear Cardiology 2017. Part 1 of 2: Positron emission tomography, computed tomography, and magnetic resonance. J Nucl Cardiol 2018; 25:320-330. [PMID: 29119374 DOI: 10.1007/s12350-017-1120-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 10/27/2017] [Indexed: 12/11/2022]
Abstract
Several original articles and editorials have been published in the Journal of Nuclear Cardiology in 2017. It has become a tradition at the beginning of each year to summarize some of these key articles in 2 sister reviews. In this first part one, we will discuss some of the progress made in the field of heart failure (cardio-oncology, myocardial blood flow, viability, dyssynchrony, and risk stratification), inflammation, molecular and hybrid imaging using advancement in positron emission tomography, computed tomography, and magnetic resonance imaging.
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Affiliation(s)
- Wael A AlJaroudi
- Division of Cardiovascular Medicine, Clemenceau Medical Center, Beirut, Lebanon
| | - Fadi G Hage
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, 306 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL, 35294-0007, USA.
- Section of Cardiology, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA.
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Affiliation(s)
- Lingzhou Zhao
- Department of Nuclear Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Xiangyang Shi
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China
- CQM-Centro de Química da Madeira, Universidade da Madeira, Funchal, Portugal
| | - Jinhua Zhao
- Department of Nuclear Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
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Can PET/MR Imaging Assess Coronary Artery Plaque Biology? JACC Cardiovasc Imaging 2017; 10:1113-1115. [DOI: 10.1016/j.jcmg.2016.12.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 12/15/2016] [Indexed: 10/18/2022]
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Schindler TH. Cardiovascular PET/MR imaging: Quo Vadis? J Nucl Cardiol 2017; 24:1007-1018. [PMID: 27659454 DOI: 10.1007/s12350-016-0451-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 02/08/2016] [Indexed: 12/30/2022]
Abstract
With the recent advent of PET/MRI scanners, the combination of molecular imaging with a variety of known and novel PET radiotracers, the high spatial resolution of MRI, and its potential for multi-parametric imaging are anticipated to increase the diagnostic accuracy in cardiovascular disease detection, while providing novel mechanistic insights into the initiation and progression of the disease state. For the time being, cardiac PET/MRI emerges as potential clinical tool in the identification and characterization of infiltrative cardiac diseases, such as sarcoidosis, acute or chronic myocarditis, and cardiac tumors, respectively. The application of PET/MRI in conjunction with various radiotracer probes in the identification of the vulnerable atherosclerotic plaque also holds much promise but needs further translation and validation in clinical investigations. The combination of molecular imaging and creation of multi-parametric imaging maps with PET/MRI, however, are likely to set new horizons to develop predictive parameters for myocardial recovery and treatment response in ischemic and non-ischemic cardiomyopathy patients. Molecular imaging and multi-parametric imaging in cardiovascular disease with PET/MRI at current stage are at its infancy but bear a bright future.
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Affiliation(s)
- Thomas Hellmut Schindler
- Department of Radiology and Radiological Science, Division of Nuclear Medicine, Nuclear Cardiovascular Medicine, Johns Hopkins University School of Medicine, 3225, 601 N. Caroline Street, Baltimore, MD, 21287, USA.
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Nekolla SG, Cabello J. The foundation layer of quantitative cardiac PET/MRI: Attenuation correction. Again. J Nucl Cardiol 2017; 24:847-850. [PMID: 26905430 DOI: 10.1007/s12350-016-0424-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 01/22/2016] [Indexed: 10/22/2022]
Affiliation(s)
- Stephan G Nekolla
- Nuklearmedizinische Klinik Und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
- DZKH (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.), Partner Site Munich Heart Alliance, Munich, Germany.
| | - Jorge Cabello
- Nuklearmedizinische Klinik Und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany
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Schwaiger M, Kunze K, Rischpler C, Nekolla SG. PET/MR: Yet another Tesla? J Nucl Cardiol 2017; 24:1019-1031. [PMID: 27659455 DOI: 10.1007/s12350-016-0665-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 08/19/2016] [Indexed: 12/20/2022]
Abstract
After the successful introduction of PET/CT as a multimodality imaging technique, PET/MR has subsequently emerged as an attractive instrumentation for applications in neurology, oncology, and cardiology. Simultaneous data acquisition combining structural, functional, and molecular imaging provides a unique platform to link various aspects of cardiac performance for the non-invasive characterization of cardiovascular disease phenotypes. Specifically, tissue characterization by MR techniques with and without contrast agents allows for functional parameters such as LGE, myocardial perfusion, and T1 maps as well as an estimate of extracellular volume. PET tracers excel by their high sensitivity and specificity, thus supplementing the functional tissue characterization by MRI. Although the clinical applications are yet to be validated , the first experience with PET/MR suggests future applications in the area of vascular imaging (unstable plaque) as well as in the characterization of inflammatory processes involving the heart. Ischemic heart disease can be comprehensively assessed by integrating regional function, perfusion, and viability. Future technical improvements leading to less costly PET/MR instrumentation are necessary to support routine clinical application of this promising technique in cardiology.
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Affiliation(s)
- Markus Schwaiger
- Department of Nuclear Medicine, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Straße 22, 81675, Munich, Germany.
| | - Karl Kunze
- Department of Nuclear Medicine, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Straße 22, 81675, Munich, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Straße 22, 81675, Munich, Germany
| | - Stephan G Nekolla
- Department of Nuclear Medicine, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Straße 22, 81675, Munich, Germany
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Systems, Physics, and Instrumentation of PET/MRI for Cardiovascular Studies. CURRENT CARDIOVASCULAR IMAGING REPORTS 2017. [DOI: 10.1007/s12410-017-9414-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Robson PM, Dweck MR, Trivieri MG, Abgral R, Karakatsanis NA, Contreras J, Gidwani U, Narula JP, Fuster V, Kovacic JC, Fayad ZA. Coronary Artery PET/MR Imaging: Feasibility, Limitations, and Solutions. JACC Cardiovasc Imaging 2017; 10:1103-1112. [PMID: 28109921 DOI: 10.1016/j.jcmg.2016.09.029] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVES The aims of this study were to describe the authors' initial experience with combined coronary artery positron emission tomographic (PET) and magnetic resonance (MR) imaging using 18F-fluorodeoxyglucose (18F-FDG) and 18F-sodium fluoride (18F-NaF) radiotracers, describe common problems and their solutions, and demonstrate the feasibility of coronary PET/MR imaging in appropriate patients. BACKGROUND Recently, PET imaging has been applied to the aortic valve and regions of atherosclerosis. 18F-FDG PET imaging has become established for imaging inflammation in atherosclerosis in the aorta and carotid arteries. Moreover, 18F-NaF has emerged as a novel tracer of active microcalcification in the aortic valve and coronary arteries. Coronary PET imaging remains challenging because of the small caliber of the vessels and their complex motion. Currently, most coronary imaging uses combined PET and computed tomographic imaging, but there is increasing enthusiasm for PET/MR imaging because of its reduced radiation, potential to correct for motion, and the complementary information available from cardiac MR in a single scan. METHODS Twenty-three patients with diagnosed or documented risk factors for coronary artery disease underwent either 18F-FDG or 18F-NaF PET/MR imaging. Standard breath-held MR-based attenuation correction was compared with a novel free-breathing approach. The impact on PET image artifacts and the interpretation of vascular uptake were evaluated semiquantitatively by expert readers. Moreover, PET reconstructions with more algorithm iterations were compared visually and by target-to-background ratio. RESULTS Image quality was significantly improved by novel free-breathing attenuation correction. Moreover, conspicuity of coronary uptake was improved by increasing the number of algorithm iterations from 3 to 6. Elevated radiotracer uptake could be localized to individual coronary lesions using both 18F-FDG (n = 1, maximal target-to-background ratio = 1.61) and 18F-NaF (n = 7, maximal target-to-background ratio = 1.55 ± 0.37), including in 1 culprit plaque post-myocardial infarction confirmed by myocardial late gadolinium enhancement. CONCLUSIONS The authors provide the first demonstration of successful, low-radiation (7.2 mSv) PET/MR imaging of inflammation and microcalcification activity in the coronary arteries. However, this requires specialized approaches tailored to coronary imaging for both attenuation correction and PET reconstruction.
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Affiliation(s)
- Philip M Robson
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
| | - Marc R Dweck
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Maria Giovanna Trivieri
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ronan Abgral
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Nuclear Medicine, University Hospital of Brest, European University of Brittany, EA3878 GETBO, Brest, France
| | - Nicolas A Karakatsanis
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Johanna Contreras
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Umesh Gidwani
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jagat P Narula
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Valentin Fuster
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jason C Kovacic
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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Masuda A, Takeishi Y. Current Status and Future Direction of PET/MR in Cardiology. ACTA ACUST UNITED AC 2017. [DOI: 10.17996/anc.17-00018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Atsuro Masuda
- Department of Cardiovascular Medicine, Fukushima Medical University
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Maughan NM, Eldib M, Conti M, Knešaurek K, Faul D, Parikh PJ, Fayad ZA, Laforest R. Phantom study to determine optimal PET reconstruction parameters for PET/MR imaging of
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Y microspheres following radioembolization. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/1/015009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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