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Alyami AS, Madkhali Y, Majrashi NA, Alwadani B, Elbashir M, Ali S, Ageeli W, El-Bahkiry HS, Althobity AA, Refaee T. The role of molecular imaging in detecting fibrosis in Crohn's disease. Ann Med 2024; 56:2313676. [PMID: 38346385 PMCID: PMC10863520 DOI: 10.1080/07853890.2024.2313676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 01/30/2024] [Indexed: 02/15/2024] Open
Abstract
Fibrosis is a pathological process that occurs due to chronic inflammation, leading to the proliferation of fibroblasts and the excessive deposition of extracellular matrix (ECM). The process of long-term fibrosis initiates with tissue hypofunction and progressively culminates in the ultimate manifestation of organ failure. Intestinal fibrosis is a significant complication of Crohn's disease (CD) that can result in persistent luminal narrowing and strictures, which are difficult to reverse. In recent years, there have been significant advances in our understanding of the cellular and molecular mechanisms underlying intestinal fibrosis in inflammatory bowel disease (IBD). Significant progress has been achieved in the fields of pathogenesis, diagnosis, and management of intestinal fibrosis in the last few years. A significant amount of research has also been conducted in the field of biomarkers for the prediction or detection of intestinal fibrosis, including novel cross-sectional imaging modalities such as positron emission tomography (PET) and single photon emission computed tomography (SPECT). Molecular imaging represents a promising biomedical approach that enables the non-invasive visualization of cellular and subcellular processes. Molecular imaging has the potential to be employed for early detection, disease staging, and prognostication in addition to assessing disease activity and treatment response in IBD. Molecular imaging methods also have a potential role to enabling minimally invasive assessment of intestinal fibrosis. This review discusses the role of molecular imaging in combination of AI in detecting CD fibrosis.
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Affiliation(s)
- Ali S. Alyami
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Yahia Madkhali
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Naif A. Majrashi
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Bandar Alwadani
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Meaad Elbashir
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Sarra Ali
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Wael Ageeli
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Hesham S. El-Bahkiry
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Abdullah A. Althobity
- Department of Radiological Sciences and Medical Imaging, College of Applied Medical Sciences, Majmaah University, Majmaah, Saudi Arabia
| | - Turkey Refaee
- Department of Diagnostic Radiography Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
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Lindemann ME, Gratz M, Grafe H, Jannusch K, Umutlu L, Quick HH. Systematic evaluation of human soft tissue attenuation correction in whole-body PET/MR: Implications from PET/CT for optimization of MR-based AC in patients with normal lung tissue. Med Phys 2024; 51:192-208. [PMID: 38060671 DOI: 10.1002/mp.16863] [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] [Received: 05/04/2023] [Revised: 11/10/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024] Open
Abstract
BACKGROUND Attenuation correction (AC) is an important methodical step in positron emission tomography/magnetic resonance imaging (PET/MRI) to correct for attenuated and scattered PET photons. PURPOSE The overall quality of magnetic resonance (MR)-based AC in whole-body PET/MRI was evaluated in direct comparison to computed tomography (CT)-based AC serving as reference. The quantitative impact of isolated tissue classes in the MR-AC was systematically investigated to identify potential optimization needs and strategies. METHODS Data of n = 60 whole-body PET/CT patients with normal lung tissue and without metal implants/prostheses were used to generate six different AC-models based on the CT data for each patient, simulating variations of MR-AC. The original continuous CT-AC (CT-org) is referred to as reference. A pseudo MR-AC (CT-mrac), generated from CT data, with four tissue classes and a bone atlas represents the MR-AC. Relative difference in linear attenuation coefficients (LAC) and standardized uptake values were calculated. From the results two improvements regarding soft tissue AC and lung AC were proposed and evaluated. RESULTS The overall performance of MR-AC is in good agreement compared to CT-AC. Lungs, heart, and bone tissue were identified as the regions with most deviation to the CT-AC (myocardium -15%, bone tissue -14%, and lungs ±20%). Using single-valued LACs for AC in the lung only provides limited accuracy. For improved soft tissue AC, splitting the combined soft tissue class into muscles and organs each with adapted LAC could reduce the deviations to the CT-AC to < ±1%. For improved lung AC, applying a gradient LAC in the lungs could remarkably reduce over- or undercorrections in PET signal compared to CT-AC (±5%). CONCLUSIONS The AC is important to ensure best PET image quality and accurate PET quantification for diagnostics and radiotherapy planning. The optimized segment-based AC proposed in this study, which was evaluated on PET/CT data, inherently reduces quantification bias in normal lung tissue and soft tissue compared to the CT-AC reference.
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Affiliation(s)
- Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Marcel Gratz
- 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
| | - Hong Grafe
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Kai Jannusch
- Department of Diagnostic and Interventional Radiology, University Hospital Duesseldorf, University Duesseldorf, Duesseldorf, Germany
| | - Lale Umutlu
- 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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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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Veit-Haibach P, Ahlström H, Boellaard R, Delgado Bolton RC, Hesse S, Hope T, Huellner MW, Iagaru A, Johnson GB, Kjaer A, Law I, Metser U, Quick HH, Sattler B, Umutlu L, Zaharchuk G, Herrmann K. International EANM-SNMMI-ISMRM consensus recommendation for PET/MRI in oncology. Eur J Nucl Med Mol Imaging 2023; 50:3513-3537. [PMID: 37624384 PMCID: PMC10547645 DOI: 10.1007/s00259-023-06406-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
PREAMBLE The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. The merged International Society for Magnetic Resonance in Medicine (ISMRM) is an international, nonprofit, scientific association whose purpose is to promote communication, research, development, and applications in the field of magnetic resonance in medicine and biology and other related topics and to develop and provide channels and facilities for continuing education in the field.The ISMRM was founded in 1994 through the merger of the Society of Magnetic Resonance in Medicine and the Society of Magnetic Resonance Imaging. SNMMI, ISMRM, and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine and/or magnetic resonance imaging. The SNMMI, ISMRM, and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and/or magnetic resonance imaging and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice guideline, representing a policy statement by the SNMMI/EANM/ISMRM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI, ISMRM, and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging and magnetic resonance imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by those entities not providing these services is not authorized. These guidelines are an educational tool designed to assist practitioners in providing appropriate care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI, the ISMRM, and the EANM caution against the use of these guidelines in litigation in which the clinical decisions of a practitioner are called into question. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the guidelines. The practice of medicine includes both the art and the science of the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognized that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.
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Affiliation(s)
- Patrick Veit-Haibach
- Joint Department Medical Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, Toronto General Hospital, 1 PMB-275, 585 University Avenue, Toronto, Ontario, M5G 2N2, Canada
- Joint Department of Medical Imaging, University of Toronto, Toronto, Canada
| | - Håkan Ahlström
- Department of Surgical Sciences, Uppsala University, 751 85, Uppsala, Sweden
- Antaros Medical AB, BioVenture Hub, 431 53, Mölndal, Sweden
| | - Ronald Boellaard
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen, The Netherlands
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Roberto C Delgado Bolton
- Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, University Hospital San Pedro and Centre for Biomedical Research of La Rioja (CIBIR), Logroño, La Rioja, Spain
| | - Swen Hesse
- Department of Nuclear Medicine, University of Leipzig Medical Center, Leipzig, Germany
| | - Thomas Hope
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Martin W Huellner
- Department of Nuclear Medicine, University Hospital Zürich, University of Zürich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Andrei Iagaru
- Department of Radiology, Division of Nuclear Medicine, Stanford University Medical Center, Stanford, CA, USA
| | - Geoffrey B Johnson
- Division of Nuclear Medicine, Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen, Denmark
| | - Ur Metser
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Essen, Germany
| | - Bernhard Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Greg Zaharchuk
- Division of Neuroradiology, Department of Radiology, Stanford University, 300 Pasteur Drive, Room S047, Stanford, CA, 94305-5105, USA
| | - Ken Herrmann
- Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany.
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Meng N, Wong KYK, Zhao M, Cheung JP, Zhang T. Radiograph-comparable image synthesis for spine alignment analysis using deep learning with prospective clinical validation. EClinicalMedicine 2023; 61:102050. [PMID: 37425371 PMCID: PMC10329130 DOI: 10.1016/j.eclinm.2023.102050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 07/11/2023] Open
Abstract
Background Adolescent idiopathic scoliosis (AIS) is the most common type of spinal disorder affecting children. Clinical screening and diagnosis require physical and radiographic examinations, which are either subjective or increase radiation exposure. We therefore developed and validated a radiation-free portable system and device utilising light-based depth sensing and deep learning technologies to analyse AIS by landmark detection and image synthesis. Methods Consecutive patients with AIS attending two local scoliosis clinics in Hong Kong between October 9, 2019, and May 21, 2022, were recruited. Patients were excluded if they had psychological and/or systematic neural disorders that could influence the compliance of the study and/or the mobility of the patients. For each participant, a Red Green Blue-Depth (RGBD) image of the nude back was collected using our in-house radiation-free device. Manually labelled landmarks and alignment parameters by our spine surgeons were considered as the ground truth (GT). Images from training and internal validation cohorts (n = 1936) were used to develop the deep learning models. The model was then prospectively validated on another cohort (n = 302) which was collected in Hong Kong and had the same demographic properties as the training cohort. We evaluated the prediction accuracy of the model on nude back landmark detection as well as the performance on radiograph-comparable image (RCI) synthesis. The obtained RCIs contain sufficient anatomical information that can quantify disease severities and curve types. Findings Our model had a consistently high accuracy in predicting the nude back anatomical landmarks with a less than 4-pixel error regarding the mean Euclidian and Manhattan distance. The synthesized RCI for AIS severity classification achieved a sensitivity and negative predictive value of over 0.909 and 0.933, and the performance for curve type classification was 0.974 and 0.908, with spine specialists' manual assessment results on real radiographs as GT. The estimated Cobb angle from synthesized RCIs had a strong correlation with the GT angles (R2 = 0.984, p < 0.001). Interpretation The radiation-free medical device powered by depth sensing and deep learning techniques can provide instantaneous and harmless spine alignment analysis which has the potential for integration into routine screening for adolescents. Funding Innovation and Technology Fund (MRP/038/20X), Health Services Research Fund (HMRF) 08192266.
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Affiliation(s)
- Nan Meng
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- CoNova Medical Technology Limited, Hong Kong SAR, China
| | - Kwan-Yee K. Wong
- Department of Computer Science, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Moxin Zhao
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jason P.Y. Cheung
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Teng Zhang
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- CoNova Medical Technology Limited, Hong Kong SAR, China
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Whittington B, Dweck MR, van Beek EJR, Newby D, Williams MC. PET-MRI of Coronary Artery Disease. J Magn Reson Imaging 2023; 57:1301-1311. [PMID: 36524452 DOI: 10.1002/jmri.28554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022] Open
Abstract
Simultaneous positron emission tomography and magnetic resonance imaging (PET-MRI) combines the anatomical detail and tissue characterization of MRI with the functional information from PET. Within the coronary arteries, this hybrid technique can be used to identify biological activity combined with anatomically high-risk plaque features to better understand the processes underlying coronary atherosclerosis. Furthermore, the downstream effects of coronary artery disease on the myocardium can be characterized by providing information on myocardial perfusion, viability, and function. This review will describe the current capabilities of PET-MRI in coronary artery disease and discuss the limitations and future directions of this emerging technique. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Beth Whittington
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging Facility QMRI, University of Edinburgh, Edinburgh, UK
| | - Marc R Dweck
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging Facility QMRI, University of Edinburgh, Edinburgh, UK
| | | | - David Newby
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging Facility QMRI, University of Edinburgh, Edinburgh, UK
| | - Michelle C Williams
- BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging Facility QMRI, University of Edinburgh, Edinburgh, UK
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7
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Borhani A, Afyouni S, Attari MMA, Mohseni A, Catalano O, Kamel IR. PET/MR enterography in inflammatory bowel disease: A review of applications and technical considerations. Eur J Radiol 2023; 163:110846. [PMID: 37121100 DOI: 10.1016/j.ejrad.2023.110846] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 05/02/2023]
Abstract
Positron emission tomography (PET) magnetic resonance (MR) enterography is a novel hybrid imaging technique that is gaining popularity in the study of complex inflammatory disorders of the gastrointestinal system, such as inflammatory bowel disease (IBD). This imaging technique combines the metabolic information of PET imaging with the spatial resolution and soft tissue contrast of MR imaging. Several studies have suggested potential roles for PET/MR imaging in determining the activity status of IBD, evaluating treatment response, stratifying risk, and predicting long-term clinical outcomes. However, there are challenges in generalizing findings due to limited studies, technical aspects of hybrid MR/PET imaging, and clinical indications of this imaging modality. This review aims to further elucidate the possible role of PET/MR in IBD, highlight important technical aspects of imaging, and address potential pitfalls and prospects of this modality in IBDs.
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Affiliation(s)
- Ali Borhani
- Russell H. Morgan Department of Radiology and Radiological Sciences, John's Hopkins Medicine, John's Hopkins University, Baltimore, MD, United States
| | - Shadi Afyouni
- Russell H. Morgan Department of Radiology and Radiological Sciences, John's Hopkins Medicine, John's Hopkins University, Baltimore, MD, United States
| | - Mohammad Mirza Aghazadeh Attari
- Russell H. Morgan Department of Radiology and Radiological Sciences, John's Hopkins Medicine, John's Hopkins University, Baltimore, MD, United States
| | - Alireza Mohseni
- Russell H. Morgan Department of Radiology and Radiological Sciences, John's Hopkins Medicine, John's Hopkins University, Baltimore, MD, United States
| | - Onofrio Catalano
- Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, United States; Harvard Medical School, 25 Shattuck St, Boston, MA 02115, United States
| | - Ihab R Kamel
- Russell H. Morgan Department of Radiology and Radiological Sciences, John's Hopkins Medicine, John's Hopkins University, Baltimore, MD, United States.
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Lindemann ME, Gratz M, Blumhagen JO, Jakoby B, Quick HH. MR-based truncation correction using an advanced HUGE method to improve attenuation correction in PET/MR imaging of obese patients. Med Phys 2022; 49:865-877. [PMID: 35014697 DOI: 10.1002/mp.15446] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 12/08/2021] [Accepted: 12/18/2021] [Indexed: 10/19/2022] Open
Abstract
PURPOSE Truncation artifacts in the periphery of the magnetic resonance (MR) field-of-view (FOV) and thus, in the MR-based attenuation correction (AC) map, may hamper accurate positron emission tomography (PET) quantification in whole-body PET/MR, which is especially problematic in patients with obesity with overall large body dimensions. Therefore, an advanced truncation correction (TC) method to extend the conventional MR FOV is needed. METHODS The extent of MR-based AC-map truncations in obese patients was determined in a data set including n = 10 patients that underwent whole-body PET/MR exams. Patient inclusion criteria were defined as BMI > 30 kg/m2 and body weight > 100 kg. Truncations in PET/MR patients with obesity were quantified comparing the MR-based AC-map volume to segmented non-AC PET data, serving as the reference body volume without truncations to demonstrate the need of improved TC. The new method implemented in this study, termed "advanced HUGE", was modified and extended from the original HUGE method by Blumhagen et al. in order to provide improved TC across the entire axial MR FOV and to unlock new clinical applications of PET/MR. Advanced HUGE was then systematically tested in PET/MR NEMA phantom measurements. Relative differences between computed tomography (CT) AC PET data of the phantom setup (reference) and MR-based Dixon AC, respectively Dixon + advanced HUGE AC, were calculated. The applicability of the method for advanced TC was then demonstrated in first MR-based measurements in healthy volunteers. RESULTS It was found that the MR-based AC maps of obese patients often reveal truncations in anterior-posterior direction. Especially the abdominal region could benefit from improved TC, where maximal relative differences in the AC-map volume up to -17 % were calculated. Applying advanced HUGE to improve the MR-based AC in PET/MR, PET quantification errors in the large-volume phantom setup could be considerably reduced from average -18.6 % (Dixon AC) to 4.6 % compared to the CT AC reference. Volunteer measurements demonstrate that formerly missing AC-map volume in the Dixon-VIBE AC-map could be added due to advanced HUGE in anterior-posterior direction and thus, potentially improves AC in PET/MR. CONCLUSIONS The advanced HUGE method for truncation correction considerably reduces truncations in anterior-posterior direction demonstrated in phantom measurements and healthy volunteers and thus, further improves MR-based AC in PET/MR imaging. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Marcel Gratz
- 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
| | | | | | - 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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Sari H, Reaungamornrat J, Catalano O, Vera-Olmos J, Izquierdo-Garcia D, Morales MA, Torrado-Carvajal A, Ng SCT, Malpica N, Kamen A, Catana C. Evaluation of Deep Learning-based Approaches to Segment Bowel Air Pockets and Generate Pelvis Attenuation Maps from CAIPIRINHA-accelerated Dixon MR Images. J Nucl Med 2021; 63:468-475. [PMID: 34301782 DOI: 10.2967/jnumed.120.261032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 06/06/2021] [Indexed: 11/16/2022] Open
Abstract
Attenuation correction (AC) remains a challenge in pelvis PET/MR imaging. In addition to the segmentation/model-based approaches, deep learning methods have shown promise in synthesizing accurate pelvis attenuation maps (μ-maps). However, these methods often misclassify air pockets in the digestive tract, which can introduce bias in the reconstructed PET images. The aims of this work were to develop deep learning-based methods to automatically segment air pockets and generate pseudo-CT images from CAIPIRINHA-accelerated MR Dixon images. Methods: A convolutional neural network (CNN) was trained to segment air pockets using 3D CAIPIRINHA-accelerated MR Dixon datasets from 35 subjects and was evaluated against semi-automated segmentations. A separate CNN was trained to synthesize pseudo-CT μ-maps from the Dixon images. Its accuracy was evaluated by comparing the deep learning-, model- and CT-based μ-maps using data from 30 of the subjects. Finally, the impact of different μ-maps and air pocket segmentation methods on the PET quantification was investigated. Results: Air pockets segmented using the CNN agreed well with semi-automated segmentations, with a mean Dice similarity coefficient of 0.75. Volumetric similarity score between two segmentations was 0.85 ± 0.14. The mean absolute relative change (RCs) with respect to the CT-based μ-maps were 2.6% and 5.1% in the whole pelvis for the deep learning and model-based μ-maps, respectively. The average RC between PET images reconstructed with deep learning and CT-based μ-maps was 2.6%. Conclusion: We presented a deep learning-based method to automatically segment air pockets from CAIPIRINHA-accelerated Dixon images with comparable accuracy to semi-automatic segmentations. We also showed that the μ-maps synthesized using a deep learning-based method from CAIPIRINHA-accelerated Dixon images are more accurate than those generated with the model-based approach available on integrated PET/MRI scanner.
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Affiliation(s)
- Hasan Sari
- Athinoula A. Martinos Center for Biomedical Imaging, United States
| | | | - Onofrio Catalano
- Athinoula A. Martinos Center for Biomedical Imaging, United States
| | | | | | | | | | | | | | - Ali Kamen
- Siemens Corporate Research, United States
| | - Ciprian Catana
- Athinoula A. Martinos Center for Biomedical Imaging, United States
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Obmann VC, Grosse-Hokamp N, Alberts I, Fulton N, Rassouli N, Siegel C, Avril N, Herrmann KA. Diagnosis and staging of hepatobiliary malignancies: Potential incremental value of (18)F-FDG-PET/MRI compared to MRI of the liver. Nuklearmedizin 2021; 60:355-367. [PMID: 34102690 DOI: 10.1055/a-1486-3671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The purpose of the study was to investigate the potential added value of 18F-FDG-PET/MRI (functional information derived from PET) over standard diagnostic liver MRI (excellent soft tissue characterization) in diagnosing and staging suspected primary hepatobiliary malignancies including extrahepatic cholangiocarcinoma (ECC), intrahepatic cholangiocellular carcinoma (ICC) and gallbladder cancer (GBCA). METHODS Twenty consecutive patients with suspected hepatobiliary malignancy were included in this retrospective study. All patients underwent combined whole-body (WB) 18F-FDG-PET/MRI including contrast-enhanced MRI of the liver, contrast-enhanced WB-MRI and WB 18F-FDG-PET. Two experienced readers staged hepatobiliary disease using TNM criteria: first based on MRI alone and then based on combined 18F-FDG-PET/MRI. Subsequently, the impact of FDG-PET/MRI on clinical management compared to MRI alone was recorded. Histopathologic proof served as the reference standard. RESULTS Hepatobiliary neoplasms were present in 16/20 patients (ECC n = 3, ICC n = 8, GBCA n = 5), two patients revealed benign disease, two were excluded. TNM staging with 18F-FDG-PET/MRI was identical to MRI alone in 11/18 (61.1 %) patients and correctly changed the stage in 4/18 (22.2 %), resulting in a change in management for 2/4 patients (11.1 %). 18F-FDG-PET/MRI was false-positive in 3/18 cases (16.7 %). Both MRI and 18F-FDG-PET/MRI were falsely positive in 1 case without malignancy. CONCLUSIONS A small incremental benefit of 18F-FDG-PET/MRI over standard MRI of the liver was observed. However, in some cases 18F-FDG-PET/MRI may lead to false-positive findings. Overall there is seemingly limited role of 18F-FDG-PET/MRI in patients with suspected hepatobiliary malignancy.
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Affiliation(s)
- Verena Carola Obmann
- Diagnostic, Interventional and Pediatric Radiology, Inselspital, University Hospital, University of Bern, Switzerland.,Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, United States
| | - Nils Grosse-Hokamp
- Department of Diagnostic and Interventional Radiology, University Cologne, Faculty of Medicine and University Hospital Cologne, Germany.,Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, United States
| | - Ian Alberts
- Nuclear Medicine, Inselspital University Hospital Bern, Switzerland
| | | | - Negin Rassouli
- Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, United States
| | - Christopher Siegel
- Department of General Surgery, Cleveland Clinic Foundation, Hillcrest Hospital, Mayfield Heights, United States
| | - Norbert Avril
- Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, United States
| | - Karin Anna Herrmann
- Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, United States
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Bruckmann NM, Lindemann ME, Grueneisen J, Grafe H, Li Y, Sawicki LM, Rischpler C, Herrmann K, Umutlu L, Quick HH, Schaarschmidt BM. Comparison of pre- and post-contrast-enhanced attenuation correction using a CAIPI-accelerated T1-weighted Dixon 3D-VIBE sequence in 68Ga-DOTATOC PET/MRI. Eur J Radiol 2021; 139:109691. [PMID: 33892276 DOI: 10.1016/j.ejrad.2021.109691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To investigate the influence of contrast agent administration on attenuation correction (AC) based on a CAIPIRINHA (CAIPI)-accelerated T1-weighted Dixon 3D-VIBE sequence in 68Ga-DOTATOC PET/MRI. MATERIAL AND METHODS Fifty-one patients with neuroendocrine tumors underwent whole-body 68Ga-DOTATOC PET/MRI for tumor staging. Two PET reconstructions were performed using AC-maps that were created using a high-resolution CAIPI-accelerated Dixon-VIBE sequence with an additional bone atlas and truncation correction using the HUGE (B0 homogenization using gradient enhancement) method before and after application of Gadolinium (Gd)-based contrast agent. Standardized uptake values (SUVs) of 21 volumes of interest (VOIs) were compared between in both PET data sets per patient. A student's t-test for paired samples was performed to test for potential differences between both AC-maps and both reconstructed PET data sets. Bonferroni correction was performed to prevent α-error accumulation, p < 0.0024 was considered to indicate statistical significance. RESULTS Significant quantitative differences between SUVmax were found in the perirenal fat (19.65 ± 48.03 %, p < 0.0001), in the axillary fat (17.46 ± 63.67 %, p < 0.0001) and in the dorsal subcutaneous fat on level of lumbar vertebral body L4 (10.26 ± 25.29 %, p < 0.0001). Significant differences were also evident in the lungs apical (5.80 ± 10.53 %, p < 0.0001), dorsal at the level of the pulmonary trunk (15.04 ± 19.09 %, p < 0.0001) and dorsal in the basal lung (51.27 ± 147.61 %, p < 0.0001). CONCLUSION The administration of (Gd)-contrast agents in this study has shown a considerable influence on the AC-maps in PET/MRI and, consequently impacted quantification in the reconstructed PET data. Therefore, dedicated PET/MRI staging protocols have to be adjusted so that AC-map acquisition is performed prior to contrast agent administration.
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Affiliation(s)
- Nils Martin Bruckmann
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Dusseldorf, D-40225, Germany.
| | - Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Johannes Grueneisen
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Hong Grafe
- High-Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany; Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Yan Li
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Lino M Sawicki
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Dusseldorf, D-40225, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
| | - Benedikt Michael Schaarschmidt
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, D-45147, Germany
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Wang T, Lei Y, Fu Y, Wynne JF, Curran WJ, Liu T, Yang X. A review on medical imaging synthesis using deep learning and its clinical applications. J Appl Clin Med Phys 2021; 22:11-36. [PMID: 33305538 PMCID: PMC7856512 DOI: 10.1002/acm2.13121] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/12/2020] [Accepted: 11/21/2020] [Indexed: 02/06/2023] Open
Abstract
This paper reviewed the deep learning-based studies for medical imaging synthesis and its clinical application. Specifically, we summarized the recent developments of deep learning-based methods in inter- and intra-modality image synthesis by listing and highlighting the proposed methods, study designs, and reported performances with related clinical applications on representative studies. The challenges among the reviewed studies were then summarized with discussion.
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Affiliation(s)
- Tonghe Wang
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
- Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Yang Lei
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
| | - Yabo Fu
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
| | - Jacob F. Wynne
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
| | - Walter J. Curran
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
- Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Tian Liu
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
- Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Xiaofeng Yang
- Department of Radiation OncologyEmory UniversityAtlantaGAUSA
- Winship Cancer InstituteEmory UniversityAtlantaGAUSA
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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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14
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Wang T, Lei Y, Fu Y, Curran WJ, Liu T, Nye JA, Yang X. Machine learning in quantitative PET: A review of attenuation correction and low-count image reconstruction methods. Phys Med 2020; 76:294-306. [PMID: 32738777 PMCID: PMC7484241 DOI: 10.1016/j.ejmp.2020.07.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/13/2020] [Accepted: 07/21/2020] [Indexed: 02/08/2023] Open
Abstract
The rapid expansion of machine learning is offering a new wave of opportunities for nuclear medicine. This paper reviews applications of machine learning for the study of attenuation correction (AC) and low-count image reconstruction in quantitative positron emission tomography (PET). Specifically, we present the developments of machine learning methodology, ranging from random forest and dictionary learning to the latest convolutional neural network-based architectures. For application in PET attenuation correction, two general strategies are reviewed: 1) generating synthetic CT from MR or non-AC PET for the purposes of PET AC, and 2) direct conversion from non-AC PET to AC PET. For low-count PET reconstruction, recent deep learning-based studies and the potential advantages over conventional machine learning-based methods are presented and discussed. In each application, the proposed methods, study designs and performance of published studies are listed and compared with a brief discussion. Finally, the overall contributions and remaining challenges are summarized.
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Affiliation(s)
- Tonghe Wang
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA; Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Yang Lei
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA
| | - Yabo Fu
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA
| | - Walter J Curran
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA; Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Tian Liu
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA; Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Jonathon A Nye
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Xiaofeng Yang
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA; Winship Cancer Institute, Emory University, Atlanta, GA, USA.
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15
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Sudarshan VP, Egan GF, Chen Z, Awate SP. Joint PET-MRI image reconstruction using a patch-based joint-dictionary prior. Med Image Anal 2020; 62:101669. [DOI: 10.1016/j.media.2020.101669] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022]
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16
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Grafe H, Lindemann ME, Ruhlmann V, Oehmigen M, Hirmas N, Umutlu L, Herrmann K, Quick HH. Evaluation of improved attenuation correction in whole-body PET/MR on patients with bone metastasis using various radiotracers. Eur J Nucl Med Mol Imaging 2020; 47:2269-2279. [PMID: 32125487 PMCID: PMC7396397 DOI: 10.1007/s00259-020-04738-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/20/2020] [Indexed: 01/18/2023]
Abstract
Purpose This study evaluates the quantitative effect of improved MR-based attenuation correction (AC), including bone segmentation and the HUGE method for truncation correction in PET/MR whole-body hybrid imaging specifically of oncologic patients with bone metastasis and using various radiotracers. Methods Twenty-three patients that underwent altogether 28 whole-body PET/MR examinations with findings of bone metastasis were included in this study. Different radiotracers (18F-FDG, 68Ga-PSMA, 68Ga-DOTATOC, 124I–MIBG) were injected according to appropriate clinical indications. Each of the 28 whole-body PET datasets was reconstructed three times using AC with (1) standard four-compartment μ-maps (background air, lung, muscle, and soft tissue), (2) five-compartment μ-maps (adding bone), and (3) six-compartment μ-maps (adding bone and HUGE truncation correction). The SUVmax of each detected bone lesion was measured in each reconstruction to evaluate the quantitative impact of improved MR-based AC. Relative difference images between four- and six-compartment μ-maps were calculated. MR-based HUGE truncation correction was compared with the PET-based MLAA truncation correction method in all patients. Results Overall, 69 bone lesions were detected and evaluated. The mean increase in relative difference over all 69 lesions in SUVmax was 5.4 ± 6.4% when comparing the improved six-compartment AC with the standard four-compartment AC. Maximal relative difference of 28.4% was measured in one lesion. Truncation correction with HUGE worked robust and resulted in realistic body contouring in all 28 exams and for all 4 different radiotracers. Truncation correction with MLAA revealed overestimations of arm tissue volume in all PET/MR exams with 18F-FDG radiotracer and failed in all other exams with radiotracers 68Ga-PSMA, 68Ga-DOTATOC, and 124I- MIBG due to limitations in body contour detection. Conclusion Improved MR-based AC, including bone segmentation and HUGE truncation correction in whole-body PET/MR on patients with bone lesions and using various radiotracers, is important to ensure best possible diagnostic image quality and accurate PET quantification. The HUGE method for truncation correction based on MR worked robust and results in realistic body contouring, independent of the radiotracers used.
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Affiliation(s)
- Hong Grafe
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany.
| | - Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Verena Ruhlmann
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Mark Oehmigen
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Nader Hirmas
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany.,Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Zollverein, 45141, Essen, Germany
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18
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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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20
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Elschot M, Selnæs KM, Johansen H, Krüger-Stokke B, Bertilsson H, Bathen TF. The Effect of Including Bone in Dixon-Based Attenuation Correction for 18F-Fluciclovine PET/MRI of Prostate Cancer. J Nucl Med 2018; 59:1913-1917. [PMID: 29728516 DOI: 10.2967/jnumed.118.208868] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/24/2018] [Indexed: 01/04/2023] Open
Abstract
The objective of this study was to evaluate the effect of including bone in Dixon-based attenuation correction for 18F-fluciclovine PET/MRI of primary and recurrent prostate cancer. Methods: 18F-fluciclovine PET data from 2 PET/MRI studies-one for staging of high-risk prostate cancer (28 patients) and one for diagnosis of recurrent prostate cancer (81 patients)-were reconstructed with a 4-compartment (reference) and 5-compartment attenuation map. In the latter, continuous linear attenuation coefficients for bone were included by coregistration with an atlas. The SUVmax and mean 50% isocontour SUV (SUViso) of primary, locally recurrent, and metastatic lesions were compared between the 2 reconstruction methods using linear mixed-effects models. In addition, mean SUVs were obtained from bone marrow in the third lumbar vertebra (L3) to investigate the effect of including bone attenuation on lesion-to-bone marrow SUV ratios (SUVRmax and SUVRiso; recurrence study only). The 5-compartment attenuation maps were visually compared with the in-phase Dixon MR images for evaluation of bone registration errors near the lesions. P values of less than 0.05 were considered significant. Results: Sixty-two lesions from 39 patients were evaluated. Bone registration errors were found near 19 (31%) of these lesions. In the remaining 8 primary prostate tumors, 7 locally recurrent lesions, and 28 lymph node metastases without bone registration errors, use of the 5-compartment attenuation map was associated with small but significant increases in SUVmax (2.5%; 95% confidence interval [CI], 2.0%-3.0%; P < 0.001) and SUViso (2.5%; 95% CI, 1.9%-3.0%; P < 0.001), but not SUVRmax (0.2%; 95% CI, -0.5%-0.9%; P = 0.604) and SUVRiso (0.2%; 95% CI -0.6%-1.0%; P = 0.581), in comparison to the 4-compartment attenuation map. Conclusion: The investigated method for atlas-based inclusion of bone in 18F-fluciclovine PET/MRI attenuation correction has only a small effect on the SUVs of soft-tissue prostate cancer lesions, and no effect on their lesion-to-bone marrow SUVRs when using signal from L3 as a reference. The attenuation maps should always be checked for registration artifacts for lesions in or close to the bones.
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Affiliation(s)
- Mattijs Elschot
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kirsten M Selnæs
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Trondheim, Norway
| | - Håkon Johansen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Nuclear Medicine, St. Olavs Hospital, Trondheim, Norway
| | - Brage Krüger-Stokke
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology, St. Olavs Hospital, Trondheim, Norway
| | - Helena Bertilsson
- Department of Urology, St. Olavs Hospital, Trondheim, Norway; and.,Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tone F Bathen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Trondheim, Norway
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Mannheim JG, Schmid AM, Schwenck J, Katiyar P, Herfert K, Pichler BJ, Disselhorst JA. PET/MRI Hybrid Systems. Semin Nucl Med 2018; 48:332-347. [PMID: 29852943 DOI: 10.1053/j.semnuclmed.2018.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the last decade, the combination of PET and MRI in one system has proven to be highly successful in basic preclinical research, as well as in clinical research. Nowadays, PET/MRI systems are well established in preclinical imaging and are progressing into clinical applications to provide further insights into specific diseases, therapeutic assessments, and biological pathways. Certain challenges in terms of hardware had to be resolved concurrently with the development of new techniques to be able to reach the full potential of both combined techniques. This review provides an overview of these challenges and describes the opportunities that simultaneous PET/MRI systems can exploit in comparison with stand-alone or other combined hybrid systems. New approaches were developed for simultaneous PET/MRI systems to correct for attenuation of 511 keV photons because MRI does not provide direct information on gamma photon attenuation properties. Furthermore, new algorithms to correct for motion were developed, because MRI can accurately detect motion with high temporal resolution. The additional information gained by the MRI can be employed to correct for partial volume effects as well. The development of new detector designs in combination with fast-decaying scintillator crystal materials enabled time-of-flight detection and incorporation in the reconstruction algorithms. Furthermore, this review lists the currently commercially available systems both for preclinical and clinical imaging and provides an overview of applications in both fields. In this regard, special emphasis has been placed on data analysis and the potential for both modalities to evolve with advanced image analysis tools, such as cluster analysis and machine learning.
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Affiliation(s)
- Julia G Mannheim
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Andreas M Schmid
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Johannes Schwenck
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany; Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Prateek Katiyar
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Kristina Herfert
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany.
| | - Jonathan A Disselhorst
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
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Freitag MT, Kesch C, Cardinale J, Flechsig P, Floca R, Eiber M, Bonekamp D, Radtke JP, Kratochwil C, Kopka K, Hohenfellner M, Stenzinger A, Schlemmer HP, Haberkorn U, Giesel F. Simultaneous whole-body 18F-PSMA-1007-PET/MRI with integrated high-resolution multiparametric imaging of the prostatic fossa for comprehensive oncological staging of patients with prostate cancer: a pilot study. Eur J Nucl Med Mol Imaging 2017; 45:340-347. [PMID: 29038888 DOI: 10.1007/s00259-017-3854-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/05/2017] [Indexed: 01/28/2023]
Abstract
INTRODUCTION The aim of the present study was to explore the clinical feasibility and reproducibility of a comprehensive whole-body 18F-PSMA-1007-PET/MRI protocol for imaging prostate cancer (PC) patients. METHODS Eight patients with high-risk biopsy-proven PC underwent a whole-body PET/MRI (3 h p.i.) including a multi-parametric prostate MRI after 18F-PSMA-1007-PET/CT (1 h p.i.) which served as reference. Seven patients presented with non-treated PC, whereas one patient presented with biochemical recurrence. SUVmean-quantification was performed using a 3D-isocontour volume-of-interest. Imaging data was consulted for TNM-staging and compared with histopathology. PC was confirmed in 4/7 patients additionally by histopathology after surgery. PET-artifacts, co-registration of pelvic PET/MRI and MRI-data were assessed (PI-RADS 2.0). RESULTS The examinations were well accepted by patients and comprised 1 h. SUVmean-values between PET/CT (1 h p.i.) and PET/MRI (3 h p.i.) were significantly correlated (p < 0.0001, respectively) and similar to literature of 18F-PSMA-1007-PET/CT 1 h vs 3 h p.i. The dominant intraprostatic lesion could be detected in all seven patients in both PET and MRI. T2c, T3a, T3b and T4 features were detected complimentarily by PET and MRI in five patients. PET/MRI demonstrated moderate photopenic PET-artifacts surrounding liver and kidneys representing high-contrast areas, no PET-artifacts were observed for PET/CT. Simultaneous PET-readout during prostate MRI achieved optimal co-registration results. CONCLUSIONS The presented 18F-PSMA-1007-PET/MRI protocol combines efficient whole-body assessment with high-resolution co-registered PET/MRI of the prostatic fossa for comprehensive oncological staging of patients with PC.
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Affiliation(s)
- Martin T Freitag
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg, Germany.
| | - Claudia Kesch
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - Jens Cardinale
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center, Heidelberg, Germany
| | - Paul Flechsig
- Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ralf Floca
- Medical Image Computing Group, German Cancer Research Center, Heidelberg, Germany
| | - Matthias Eiber
- Department of Nuclear Medicine, Technical University Hospital Munich, Munich, Germany
| | - David Bonekamp
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg, Germany
| | - Jan P Radtke
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - Clemens Kratochwil
- Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Klaus Kopka
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center, Heidelberg, Germany
| | | | | | - Heinz-Peter Schlemmer
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg, Germany
| | - Uwe Haberkorn
- Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany
| | - Frederik Giesel
- Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany
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