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Krokos G, MacKewn J, Dunn J, Marsden P. A review of PET attenuation correction methods for PET-MR. EJNMMI Phys 2023; 10:52. [PMID: 37695384 PMCID: PMC10495310 DOI: 10.1186/s40658-023-00569-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/07/2023] [Indexed: 09/12/2023] Open
Abstract
Despite being thirteen years since the installation of the first PET-MR system, the scanners constitute a very small proportion of the total hybrid PET systems installed. This is in stark contrast to the rapid expansion of the PET-CT scanner, which quickly established its importance in patient diagnosis within a similar timeframe. One of the main hurdles is the development of an accurate, reproducible and easy-to-use method for attenuation correction. Quantitative discrepancies in PET images between the manufacturer-provided MR methods and the more established CT- or transmission-based attenuation correction methods have led the scientific community in a continuous effort to develop a robust and accurate alternative. These can be divided into four broad categories: (i) MR-based, (ii) emission-based, (iii) atlas-based and the (iv) machine learning-based attenuation correction, which is rapidly gaining momentum. The first is based on segmenting the MR images in various tissues and allocating a predefined attenuation coefficient for each tissue. Emission-based attenuation correction methods aim in utilising the PET emission data by simultaneously reconstructing the radioactivity distribution and the attenuation image. Atlas-based attenuation correction methods aim to predict a CT or transmission image given an MR image of a new patient, by using databases containing CT or transmission images from the general population. Finally, in machine learning methods, a model that could predict the required image given the acquired MR or non-attenuation-corrected PET image is developed by exploiting the underlying features of the images. Deep learning methods are the dominant approach in this category. Compared to the more traditional machine learning, which uses structured data for building a model, deep learning makes direct use of the acquired images to identify underlying features. This up-to-date review goes through the literature of attenuation correction approaches in PET-MR after categorising them. The various approaches in each category are described and discussed. After exploring each category separately, a general overview is given of the current status and potential future approaches along with a comparison of the four outlined categories.
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Affiliation(s)
- Georgios Krokos
- School of Biomedical Engineering and Imaging Sciences, The PET Centre at St Thomas' Hospital London, King's College London, 1st Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK.
| | - Jane MacKewn
- School of Biomedical Engineering and Imaging Sciences, The PET Centre at St Thomas' Hospital London, King's College London, 1st Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
| | - Joel Dunn
- School of Biomedical Engineering and Imaging Sciences, The PET Centre at St Thomas' Hospital London, King's College London, 1st Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
| | - Paul Marsden
- School of Biomedical Engineering and Imaging Sciences, The PET Centre at St Thomas' Hospital London, King's College London, 1st Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
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2
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Sun T, Wu Y, Bai Y, Wang Z, Shen C, Wang W, Li C, Hu Z, Liang D, Liu X, Zheng H, Yang Y, Wang M. An iterative image-based inter-frame motion compensation method for dynamic brain PET imaging. Phys Med Biol 2022; 67. [PMID: 35021156 DOI: 10.1088/1361-6560/ac4a8f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/12/2022] [Indexed: 11/11/2022]
Abstract
As a non-invasive imaging tool, positron emission tomography (PET) plays an important role in brain science and disease research. Dynamic acquisition is one way of brain PET imaging. Its wide application in clinical research has often been hindered by practical challenges, such as patient involuntary movement, which could degrade both image quality and the accuracy of the quantification. This is even more obvious in scans of patients with neurodegeneration or mental disorders. Conventional motion compensation methods were either based on images or raw measured data, were shown to be able to reduce the effect of motion on the image quality. As for a dynamic PET scan, motion compensation can be challenging as tracer kinetics and relatively high noise can be present in dynamic frames. In this work, we propose an image-based inter-frame motion compensation approach specifically designed for dynamic brain PET imaging. Our method has an iterative implementation that only requires reconstructed images, based on which the inter-frame subject movement can be estimated and compensated. The method utilized tracer-specific kinetic modelling and can deal with simple and complex movement patterns. The synthesized phantom study showed that the proposed method can compensate for the simulated motion in scans with18F-FDG,18F-Fallypride and18F-AV45. Fifteen dynamic18F-FDG patient scans with motion artifacts were also processed. The quality of the recovered image was superior to the one of the non-corrected images and the corrected images with other image-based methods. The proposed method enables retrospective image quality control for dynamic brain PET imaging, hence facilitating the applications of dynamic PET in clinics and research.
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Affiliation(s)
- Tao Sun
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Yaping Wu
- Henan Provincial People's Hospital and the People's Hospital of Zhengzhou, University of Zhengzhou, People's Republic of China
| | - Yan Bai
- Henan Provincial People's Hospital and the People's Hospital of Zhengzhou, University of Zhengzhou, People's Republic of China
| | - Zhenguo Wang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Chushu Shen
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Wei Wang
- United Imaging Healthcare, Shanghai, People's Republic of China
| | - Chenwei Li
- United Imaging Healthcare, Shanghai, People's Republic of China
| | - Zhanli Hu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Dong Liang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Xin Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Yongfeng Yang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, People's Republic of China
| | - Meiyun Wang
- Henan Provincial People's Hospital and the People's Hospital of Zhengzhou, University of Zhengzhou, People's Republic of China
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Polycarpou I, Soultanidis G, Tsoumpas C. Synergistic motion compensation strategies for positron emission tomography when acquired simultaneously with magnetic resonance imaging. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200207. [PMID: 34218675 PMCID: PMC8255946 DOI: 10.1098/rsta.2020.0207] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 05/04/2023]
Abstract
Subject motion in positron emission tomography (PET) is a key factor that degrades image resolution and quality, limiting its potential capabilities. Correcting for it is complicated due to the lack of sufficient measured PET data from each position. This poses a significant barrier in calculating the amount of motion occurring during a scan. Motion correction can be implemented at different stages of data processing either during or after image reconstruction, and once applied accurately can substantially improve image quality and information accuracy. With the development of integrated PET-MRI (magnetic resonance imaging) scanners, internal organ motion can be measured concurrently with both PET and MRI. In this review paper, we explore the synergistic use of PET and MRI data to correct for any motion that affects the PET images. Different types of motion that can occur during PET-MRI acquisitions are presented and the associated motion detection, estimation and correction methods are reviewed. Finally, some highlights from recent literature in selected human and animal imaging applications are presented and the importance of motion correction for accurate kinetic modelling in dynamic PET-MRI is emphasized. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 2'.
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Affiliation(s)
- Irene Polycarpou
- Department of Health Sciences, European University of Cyprus, Nicosia, Cyprus
| | - Georgios Soultanidis
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Charalampos Tsoumpas
- Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Biomedical Imaging Science Department, University of Leeds, West Yorkshire, UK
- Invicro, London, UK
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4
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Driscoll B, Vines D, Shek T, Publicover J, Yeung I, Breen S, Jaffray D. 4D-CT Attenuation Correction in Respiratory-Gated PET for Hypoxia Imaging: Is It Really Beneficial? ACTA ACUST UNITED AC 2021; 6:241-249. [PMID: 32548302 PMCID: PMC7289254 DOI: 10.18383/j.tom.2019.00027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Previous literature has shown that 4D respiratory-gated positron emission tomography (PET) is beneficial for quantitative analysis and defining targets for boosting therapy. However the case for addition of a phase-matched 4D-computed tomography (CT) for attenuation correction (AC) is less clear. We seek to validate the use of 4D-CT for AC and investigate the impact of motion correction for low signal-to-background PET imaging of hypoxia using radiotracers such as FAZA and FMISO. A new insert for the Modus Medicals' QUASAR™ Programmable Respiratory Motion Phantom was developed in which a 3D-printed sphere was placed within the "lung" compartment while an additional compartment is added to simulate muscle/blood compartment required for hypoxia quantification. Experiments are performed at 4:1 or 2:1 signal-to-background ratio consistent with clinical FAZA and FMISO imaging. Motion blur was significant in terms of SUVmax, mean, and peak for motion ≥1 cm and could be significantly reduced (from 20% to 8% at 2-cm motion) for all 4D-PET-gated reconstructions. The effect of attenuation method on precision was significant (σ2 hCT-AC = 5.5%/4.7%/2.7% vs σ2 4D-CT-AC = 0.5%/0.6%/0.7% [max%/peak%/mean% variance]). The simulated hypoxic fraction also significantly decreased under conditions of 2-cm amplitude motion from 55% to 20% and was almost fully recovered (HF = 0.52 for phase-matched 4D-CT) using gated PET. 4D-gated PET is valuable under conditions of low radiotracer uptake found in hypoxia imaging. This work demonstrates the importance of using 4D-CT for AC when performing gated PET based on its significantly improved precision over helical CT.
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Affiliation(s)
- Brandon Driscoll
- Quantitative Imaging for Personalized Cancer Medicine Program-Techna Institute, University Health Network, Toronto, ON, Canada
| | - Douglass Vines
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada; and.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Tina Shek
- Quantitative Imaging for Personalized Cancer Medicine Program-Techna Institute, University Health Network, Toronto, ON, Canada
| | - Julia Publicover
- Quantitative Imaging for Personalized Cancer Medicine Program-Techna Institute, University Health Network, Toronto, ON, Canada
| | - Ivan Yeung
- Quantitative Imaging for Personalized Cancer Medicine Program-Techna Institute, University Health Network, Toronto, ON, Canada.,Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada; and.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Stephen Breen
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada; and.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - David Jaffray
- Quantitative Imaging for Personalized Cancer Medicine Program-Techna Institute, University Health Network, Toronto, ON, Canada.,Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, Canada; and.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
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5
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Thureau S, Modzelewski R, Bohn P, Hapdey S, Gouel P, Dubray B, Vera P. Comparison of Hypermetabolic and Hypoxic Volumes Delineated on [ 18F]FDG and [ 18F]Fluoromisonidazole PET/CT in Non-small-cell Lung Cancer Patients. Mol Imaging Biol 2021; 22:764-771. [PMID: 31432388 DOI: 10.1007/s11307-019-01422-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE The high rates of failure in the radiotherapy target volume suggest that patients with stage II or III non-small-cell lung cancer (NSCLC) should receive an increased total dose of radiotherapy. 2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) and [18F]fluoromisonidazole ([18F]FMISO) (hypoxia) uptake on pre-radiotherapy positron emission tomography (PET)/X-ray computed tomography (CT) have been independently reported to identify intratumor subvolumes at higher risk of relapse after radiotherapy. We have compared the [18F]FDG and [18F]FMISO volumes defined by PET/CT in NSCLC patients included in a prospective study. PROCEDURES Thirty-four patients with non-resectable lung cancer underwent [18F]FDG and [18F]FMISO PET/CT before (pre-RT) and during radiotherapy (around 42 Gy, per-RT). The criteria were to delineate 40 % and 90 % SUVmax thresholds on [18F]FDG PET/CT (metabolic volumes), and SUV > 1.4 on pre-RT [18F]FMISO PET/CT (hypoxic volume). The functional volumes were delineated within the tumor volume as defined on co-registered CTs. RESULTS The mean pre-RT and per-RT [18F]FDG volumes were not statistically different (30.4 cc vs 22.2; P = 0.12). The mean pre-RT SUVmax [18F]FDG was higher than per-RT SUVmax (12.7 vs 6.5; P < 0.0001). The mean [18F]FMISO SUVmax and volumes were 2.7 and 1.37 cc, respectively. Volume-based analysis showed good overlap between [18F]FDG and [18F]FMISO for all methods of segmentation but a poor correlation for Jaccard or Dice Indices (DI). The DI maximum was 0.45 for a threshold at 40 or 50 %. CONCLUSION The correlation between [18F]FDG and [18F]FMISO uptake is low in NSCLC, making it possible to envisage different management strategies as the studies in progress show.
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Affiliation(s)
- Sébastien Thureau
- Department of Radiation Oncology, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108, FR CNRS 3638], Faculty of Medecine, University of Rouen, Rouen, France. .,Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France.
| | - R Modzelewski
- Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France
| | - P Bohn
- Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France
| | - S Hapdey
- Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France
| | - P Gouel
- Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France
| | - B Dubray
- Department of Radiation Oncology, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108, FR CNRS 3638], Faculty of Medecine, University of Rouen, Rouen, France
| | - P Vera
- Department of Nuclear Medicine, Henri Becquerel Cancer Center and Rouen University Hospital, & QuantIF - LITIS [EA (Equipe d'Accueil) 4108 - FR CNRS 3638], Faculty of Medicine, University of Rouen, Rouen, France
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6
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Hwang D, Kang SK, Kim KY, Choi H, Seo S, Lee JS. Data-driven respiratory phase-matched PET attenuation correction without CT. Phys Med Biol 2021; 66. [PMID: 33910170 DOI: 10.1088/1361-6560/abfc8f] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 04/28/2021] [Indexed: 12/20/2022]
Abstract
We propose a deep learning-based data-driven respiratory phase-matched gated-PET attenuation correction (AC) method that does not need a gated-CT. The proposed method is a multi-step process that consists of data-driven respiratory gating, gated attenuation map estimation using maximum-likelihood reconstruction of attenuation and activity (MLAA) algorithm, and enhancement of the gated attenuation maps using convolutional neural network (CNN). The gated MLAA attenuation maps enhanced by the CNN allowed for the phase-matched AC of gated-PET images. We conducted a non-rigid registration of the gated-PET images to generate motion-free PET images. We trained the CNN by conducting a 3D patch-based learning with 80 oncologic whole-body18F-fluorodeoxyglucose (18F-FDG) PET/CT scan data and applied it to seven regional PET/CT scans that cover the lower lung and upper liver. We investigated the impact of the proposed respiratory phase-matched AC of PET without utilizing CT on tumor size and standard uptake value (SUV) assessment, and PET image quality (%STD). The attenuation corrected gated and motion-free PET images generated using the proposed method yielded sharper organ boundaries and better noise characteristics than conventional gated and ungated PET images. A banana artifact observed in a phase-mismatched CT-based AC was not observed in the proposed approach. By employing the proposed method, the size of tumor was reduced by 12.3% and SUV90%was increased by 13.3% in tumors with larger movements than 5 mm. %STD of liver uptake was reduced by 11.1%. The deep learning-based data-driven respiratory phase-matched AC method improved the PET image quality and reduced the motion artifacts.
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Affiliation(s)
- Donghwi Hwang
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seung Kwan Kang
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyeong Yun Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hongyoon Choi
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seongho Seo
- Department of Electronic Engineering, Pai Chai University, Daejeon, Republic of Korea
| | - Jae Sung Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
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7
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Chen DL, Ballout S, Chen L, Cheriyan J, Choudhury G, Denis-Bacelar AM, Emond E, Erlandsson K, Fisk M, Fraioli F, Groves AM, Gunn RN, Hatazawa J, Holman BF, Hutton BF, Iida H, Lee S, MacNee W, Matsunaga K, Mohan D, Parr D, Rashidnasab A, Rizzo G, Subramanian D, Tal-Singer R, Thielemans K, Tregay N, van Beek EJR, Vass L, Vidal Melo MF, Wellen JW, Wilkinson I, Wilson FJ, Winkler T. Consensus Recommendations on the Use of 18F-FDG PET/CT in Lung Disease. J Nucl Med 2020; 61:1701-1707. [PMID: 32948678 PMCID: PMC9364897 DOI: 10.2967/jnumed.120.244780] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/09/2020] [Indexed: 01/04/2023] Open
Abstract
PET with 18F-FDG has been increasingly applied, predominantly in the research setting, to study drug effects and pulmonary biology and to monitor disease progression and treatment outcomes in lung diseases that interfere with gas exchange through alterations of the pulmonary parenchyma, airways, or vasculature. To date, however, there are no widely accepted standard acquisition protocols or imaging data analysis methods for pulmonary 18F-FDG PET/CT in these diseases, resulting in disparate approaches. Hence, comparison of data across the literature is challenging. To help harmonize the acquisition and analysis and promote reproducibility, we collated details of acquisition protocols and analysis methods from 7 PET centers. From this information and our discussions, we reached the consensus recommendations given here on patient preparation, choice of dynamic versus static imaging, image reconstruction, and image analysis reporting.
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Affiliation(s)
- Delphine L Chen
- Department of Radiology, University of Washington, Seattle Cancer Care Alliance, Seattle, Washington
| | - Safia Ballout
- School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom
| | - Laigao Chen
- Worldwide Research, Development, and Medical, Pfizer Inc., Cambridge, Massachusetts
| | - Joseph Cheriyan
- Cambridge University Hospitals, NHS Foundation Trust, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Gourab Choudhury
- Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Elise Emond
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Kjell Erlandsson
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Marie Fisk
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Francesco Fraioli
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Ashley M Groves
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Roger N Gunn
- inviCRO, London, United Kingdom
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University, Osaka, Japan
| | - Beverley F Holman
- Nuclear Medicine Department, Royal Free Hospital, London, United Kingdom
| | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Hidehiro Iida
- Faculty of Biomedicine and Turku PET Center, University of Turku, Turku, Finland
| | - Sarah Lee
- Amallis Consulting Ltd., London, United Kingdom
| | - William MacNee
- Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Keiko Matsunaga
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University, Osaka, Japan
| | - Divya Mohan
- Medical Innovation, Value Evidence, and Outcomes, GlaxoSmithKline R&D, Collegeville, Pennsylvania
| | - David Parr
- University Hospitals Coventry and Warwickshire, Coventry, United Kingdom
| | - Alaleh Rashidnasab
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Gaia Rizzo
- inviCRO, London, United Kingdom
- Department of Medicine, Imperial College London, London, United Kingdom
| | | | - Ruth Tal-Singer
- Medical Innovation, Value Evidence, and Outcomes, GlaxoSmithKline R&D, Collegeville, Pennsylvania
| | - Kris Thielemans
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Nicola Tregay
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Edwin J R van Beek
- Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Laurence Vass
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jeremy W Wellen
- Research and Early Development, Celgene, Cambridge, Massachusetts; and
| | - Ian Wilkinson
- Cambridge University Hospitals, NHS Foundation Trust, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Frederick J Wilson
- Clinical Imaging, Clinical Pharmacology, and Experimental Medicine, GlaxoSmithKline, Stevenage, United Kingdom
| | - Tilo Winkler
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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8
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Vass L, Fisk M, Lee S, Wilson FJ, Cheriyan J, Wilkinson I. Advances in PET to assess pulmonary inflammation: A systematic review. Eur J Radiol 2020; 130:109182. [DOI: 10.1016/j.ejrad.2020.109182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/27/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022]
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9
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Mayer J, Brown R, Thielemans K, Ovtchinnikov E, Pasca E, Atkinson D, Gillman A, Marsden P, Ippoliti M, Makowski M, Schaeffter T, Kolbitsch C. Flexible numerical simulation framework for dynamic PET-MR data. Phys Med Biol 2020; 65:145003. [PMID: 32692725 DOI: 10.1088/1361-6560/ab7eee] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This paper presents a simulation framework for dynamic PET-MR. The main focus of this framework is to provide motion-resolved MR and PET data and ground truth motion information. This can be used in the optimisation and quantitative evaluation of image registration and in assessing the error propagation due to inaccuracies in motion estimation in complex motion-compensated reconstruction algorithms. Contrast and tracer kinetics can also be simulated and are available as ground truth information. To closely emulate medical examination, input and output of the simulation are files in standardised open-source raw data formats. This enables the use of existing raw data as a template input and ensures seamless integration of the output into existing reconstruction pipelines. The proposed framework was validated in PET-MR and image registration applications. It was used to simulate a FDG-PET-MR scan with cardiac and respiratory motion. Ground truth motion information could be utilised to optimise parameters for PET and synergistic PET-MR image registration. In addition, a free-breathing dynamic contrast enhancement (DCE) abdominal scan of a patient with hepatic lesions was simulated. In order to correct for breathing motion, a motion-corrected image reconstruction scheme was used and a Toft's model was fit to the DCE data to obtain quantitative DCE-MRI parameters. Utilising the ground truth motion information, the dependency of quantitative DCE-MR images on the accuracy of the motion estimation was evaluated. We demonstrated that respiratory motion had to be available with an average accuracy of at least the spatial resolution of the DCE-MR images in order to ensure an improvement in lesions visualisation and quantification compared to no motion correction. The proposed framework provides a valuable tool with a wide range of scientific PET and MR applications and will be available as part of the open-source project Synergistic Image Reconstruction Framework (SIRF).
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Affiliation(s)
- Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany. Author to whom any correspondence should be addressed
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10
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Brusaferri L, Bousse A, Emond EC, Brown R, Tsai YJ, Atkinson D, Ourselin S, Watson CC, Hutton BF, Arridge S, Thielemans K. Joint Activity and Attenuation Reconstruction From Multiple Energy Window Data With Photopeak Scatter Re-Estimation in Non-TOF 3-D PET. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020. [DOI: 10.1109/trpms.2020.2978449] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Emond EC, Bousse A, Machado M, Porter J, Groves AM, Hutton BF, Thielemans K. Effect of attenuation mismatches in time of flight PET reconstruction. Phys Med Biol 2020; 65:085009. [PMID: 32101801 DOI: 10.1088/1361-6560/ab7a6f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
While the pursuit of better time resolution in positron emission tomography (PET) is rapidly evolving, little work has been performed on time of flight (TOF) image quality at high time resolution in the presence of modelling inconsistencies. This works focuses on the effect of using the wrong attenuation map in the system model, causing perturbations in the reconstructed radioactivity image. Previous work has usually considered the effects to be local to the area where there is attenuation mismatch, and has shown that the quantification errors in this area tend to reduce with improved time resolution. This publication shows however that errors in the PET image at a distance from the mismatch increase with time resolution. The errors depend on the reconstruction algorithm used. We quantify the errors in the hypothetical case of perfect time resolution for maximum likelihood reconstructions. In addition, we perform reconstructions on simulated and patient data. In particular, for respiratory-gated reconstructions from a wrong attenuation map, increased errors are observed with improved time resolutions in areas close to the lungs (e.g. from 13.3% in non-TOF to up to 20.9% at 200 ps in the left ventricle).
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Affiliation(s)
- Elise C Emond
- Institute of Nuclear Medicine, University College London, London NW1 2BU, United Kingdom
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12
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Lillington J, Brusaferri L, Kläser K, Shmueli K, Neji R, Hutton BF, Fraioli F, Arridge S, Cardoso MJ, Ourselin S, Thielemans K, Atkinson D. PET/MRI attenuation estimation in the lung: A review of past, present, and potential techniques. Med Phys 2020; 47:790-811. [PMID: 31794071 PMCID: PMC7027532 DOI: 10.1002/mp.13943] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 07/23/2019] [Accepted: 11/20/2019] [Indexed: 12/16/2022] Open
Abstract
Positron emission tomography/magnetic resonance imaging (PET/MRI) potentially offers several advantages over positron emission tomography/computed tomography (PET/CT), for example, no CT radiation dose and soft tissue images from MR acquired at the same time as the PET. However, obtaining accurate linear attenuation correction (LAC) factors for the lung remains difficult in PET/MRI. LACs depend on electron density and in the lung, these vary significantly both within an individual and from person to person. Current commercial practice is to use a single‐valued population‐based lung LAC, and better estimation is needed to improve quantification. Given the under‐appreciation of lung attenuation estimation as an issue, the inaccuracy of PET quantification due to the use of single‐valued lung LACs, the unique challenges of lung estimation, and the emerging status of PET/MRI scanners in lung disease, a review is timely. This paper highlights past and present methods, categorizing them into segmentation, atlas/mapping, and emission‐based schemes. Potential strategies for future developments are also presented.
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Affiliation(s)
- Joseph Lillington
- Centre for Medical Imaging, University College London, London, W1W 7TS, UK
| | - Ludovica Brusaferri
- Institute of Nuclear Medicine, University College London, London, NW1 2BU, UK
| | - Kerstin Kläser
- Centre for Medical Image Computing, University College London, London, WC1E 7JE, UK
| | - Karin Shmueli
- Magnetic Resonance Imaging Group, Department of Medical Physics & Biomedical Engineering, University College London, London, WC1E 6BT, UK
| | - Radhouene Neji
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, GU16 8QD, UK
| | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, London, NW1 2BU, UK
| | - Francesco Fraioli
- Institute of Nuclear Medicine, University College London, London, NW1 2BU, UK
| | - Simon Arridge
- Centre for Medical Image Computing, University College London, London, WC1E 7JE, UK
| | - Manuel Jorge Cardoso
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Sebastien Ourselin
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Kris Thielemans
- Institute of Nuclear Medicine, University College London, London, NW1 2BU, UK
| | - David Atkinson
- Centre for Medical Imaging, University College London, London, W1W 7TS, UK
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13
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Vass LD, Lee S, Wilson FJ, Fisk M, Cheriyan J, Wilkinson I. Reproducibility of compartmental modelling of 18F-FDG PET/CT to evaluate lung inflammation. EJNMMI Phys 2019; 6:26. [PMID: 31844995 PMCID: PMC6915187 DOI: 10.1186/s40658-019-0265-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/25/2019] [Indexed: 11/18/2022] Open
Abstract
Introduction Compartmental modelling is an established method of quantifying 18F-FDG uptake; however, only recently has it been applied to evaluate pulmonary inflammation. Implementation of compartmental models remains challenging in the lung, partly due to the low signal-to-noise ratio compared to other organs and the lack of standardisation. Good reproducibility is a key requirement of an imaging biomarker which has yet to be demonstrated in pulmonary compartmental models of 18F-FDG; in this paper, we address this unmet need. Methods Retrospective subject data were obtained from the EVOLVE observational study: Ten COPD patients (age =66±9; 8M/2F), 10 α1ATD patients (age =63±8; 7M/3F) and 10 healthy volunteers (age =68±8; 9M/1F) never smokers. PET and CT images were co-registered, and whole lung regions were extracted from CT using an automated algorithm; the descending aorta was defined using a manually drawn region. Subsequent stages of the compartmental analysis were performed by two independent operators using (i) a MIAKATTM based pipeline and (ii) an in-house developed pipeline. We evaluated the metabolic rate constant of 18F-FDG (Kim) and the fractional blood volume (Vb); Bland-Altman plots were used to compare the results. Further, we adjusted the in-house pipeline to identify the salient features in the analysis which may help improve the standardisation of this technique in the lung. Results The initial agreement on a subject level was poor: Bland-Altman coefficients of reproducibility for Kim and Vb were 0.0031 and 0.047 respectively. However, the effect size between the groups (i.e. COPD, α1ATD and healthy subjects) was similar using either pipeline. We identified the key drivers of this difference using an incremental approach: ROI methodology, modelling of the IDIF and time delay estimation. Adjustment of these factors led to improved Bland-Altman coefficients of reproducibility of 0.0015 and 0.027 for Kim and Vb respectively. Conclusions Despite similar methodology, differences in implementation can lead to disparate results in the outcome parameters. When reporting the outcomes of lung compartmental modelling, we recommend the inclusion of the details of ROI methodology, input function fitting and time delay estimation to improve reproducibility.
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Affiliation(s)
- Laurence D Vass
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Addenbrookes Hospital, Cambridge, UK.
| | | | | | - Marie Fisk
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Addenbrookes Hospital, Cambridge, UK.,Cambridge University Hospitals NHS Trust, Cambridge, UK
| | - Joseph Cheriyan
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Addenbrookes Hospital, Cambridge, UK.,GSK R &D, Brentford, UK.,Cambridge University Hospitals NHS Trust, Cambridge, UK
| | - Ian Wilkinson
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Addenbrookes Hospital, Cambridge, UK.,Cambridge University Hospitals NHS Trust, Cambridge, UK
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14
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Holman BF, Cuplov V, Millner L, Endozo R, Maher TM, Groves AM, Hutton BF, Thielemans K. Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information. EJNMMI Phys 2018; 5:14. [PMID: 29869186 PMCID: PMC5986691 DOI: 10.1186/s40658-018-0212-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 04/09/2018] [Indexed: 02/06/2023] Open
Abstract
Background Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and ‘snap shot’ CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Results Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Conclusions Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.
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Affiliation(s)
- Beverley F Holman
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK.
| | - Vesna Cuplov
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK
| | - Lynn Millner
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK
| | - Raymond Endozo
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK
| | - Toby M Maher
- National Institute for Health Research Respiratory Biomedical Research Unit, Royal Brompton Hospital, Sydney St, London, SW3 6NP, UK.,Fibrosis Research Group, Inflammation, Repair and Development Section, NHLI, Sir Alexander Flemming Building, Imperial College London, London, SW7 2AZ, UK
| | - Ashley M Groves
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK
| | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Kris Thielemans
- Institute of Nuclear Medicine, University College London, UCLH (T-5), Euston Road, London, NW1 2BU, UK
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15
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Polycarpou I, Soultanidis G, Tsoumpas C. Synthesis of Realistic Simultaneous Positron Emission Tomography and Magnetic Resonance Imaging Data. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:703-711. [PMID: 29533892 DOI: 10.1109/tmi.2017.2768130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The investigation of the performance of different positron emission tomography (PET) reconstruction and motion compensation methods requires accurate and realistic representation of the anatomy and motion trajectories as observed in real subjects during acquisitions. The generation of well-controlled clinical datasets is difficult due to the many different clinical protocols, scanner specifications, patient sizes, and physiological variations. Alternatively, computational phantoms can be used to generate large data sets for different disease states, providing a ground truth. Several studies use registration of dynamic images to derive voxel deformations to create moving computational phantoms. These phantoms together with simulation software generate raw data. This paper proposes a method for the synthesis of dynamic PET data using a fast analytic method. This is achieved by incorporating realistic models of respiratory motion into a numerical phantom to generate datasets with continuous and variable motion with magnetic resonance imaging (MRI)-derived motion modeling and high resolution MRI images. In this paper, data sets for two different clinical traces are presented, 18F-FDG and 68Ga-PSMA. This approach incorporates realistic models of respiratory motion to generate temporally and spatially correlated MRI and PET data sets, as those expected to be obtained from simultaneous PET-MRI acquisitions.
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16
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Segars WP, Tsui BMW, Jing Cai, Fang-Fang Yin, Fung GSK, Samei E. Application of the 4-D XCAT Phantoms in Biomedical Imaging and Beyond. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:680-692. [PMID: 28809677 PMCID: PMC5809240 DOI: 10.1109/tmi.2017.2738448] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The four-dimensional (4-D) eXtended CArdiac-Torso (XCAT) series of phantoms was developed to provide accurate computerized models of the human anatomy and physiology. The XCAT series encompasses a vast population of phantoms of varying ages from newborn to adult, each including parameterized models for the cardiac and respiratory motions. With great flexibility in the XCAT's design, any number of body sizes, different anatomies, cardiac or respiratory motions or patterns, patient positions and orientations, and spatial resolutions can be simulated. As such, the XCAT phantoms are gaining a wide use in biomedical imaging research. There they can provide a virtual patient base from which to quantitatively evaluate and improve imaging instrumentation, data acquisition, techniques, and image reconstruction and processing methods which can lead to improved image quality and more accurate clinical diagnoses. The phantoms have also found great use in radiation dosimetry, radiation therapy, medical device design, and even the security and defense industry. This review paper highlights some specific areas in which the XCAT phantoms have found use within biomedical imaging and other fields. From these examples, we illustrate the increasingly important role that computerized phantoms and computer simulation are playing in the research community.
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17
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The peroxisome proliferator-activated receptor agonist pioglitazone and 5-lipoxygenase inhibitor zileuton have no effect on lung inflammation in healthy volunteers by positron emission tomography in a single-blind placebo-controlled cohort study. PLoS One 2018; 13:e0191783. [PMID: 29414995 PMCID: PMC5802889 DOI: 10.1371/journal.pone.0191783] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 01/11/2018] [Indexed: 11/22/2022] Open
Abstract
Background Anti-inflammatory drug development efforts for lung disease have been hampered in part by the lack of noninvasive inflammation biomarkers and the limited ability of animal models to predict efficacy in humans. We used 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in a human model of lung inflammation to assess whether pioglitazone, a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, and zileuton, a 5-lipoxygenase inhibitor, reduce lung inflammation. Methods For this single center, single-blind, placebo-controlled cohort study, we enrolled healthy volunteers sequentially into the following treatment cohorts (N = 6 per cohort): pioglitazone plus placebo, zileuton plus placebo, or dual placebo prior to bronchoscopic endotoxin instillation. 18F-FDG uptake pre- and post-endotoxin was quantified as the Patlak graphical analysis-determined Ki (primary outcome measure). Secondary outcome measures included the mean standard uptake value (SUVmean), post-endotoxin bronchoalveolar lavage (BAL) cell counts and differentials and blood adiponectin and urinary leukotriene E4 (LTE4) levels, determined by enzyme-linked immunosorbent assay, to verify treatment compliance. One- or two-way analysis of variance assessed for differences among cohorts in the outcome measures (expressed as mean ± standard deviation). Results Ten females and eight males (29±6 years of age) completed all study procedures except for one volunteer who did not complete the post-endotoxin BAL. Ki and SUVmean increased in all cohorts after endotoxin instillation (Ki increased by 0.0021±0.0019, 0.0023±0.0017, and 0.0024±0.0020 and SUVmean by 0.47±0.14, 0.55±0.15, and 0.54±0.38 in placebo, pioglitazone, and zileuton cohorts, respectively, p<0.001) with no differences among treatment cohorts (p = 0.933). Adiponectin levels increased as expected with pioglitazone treatment but not urinary LTE4 levels as expected with zileuton treatment. BAL cell counts (p = 0.442) and neutrophil percentage (p = 0.773) were similar among the treatment cohorts. Conclusions Endotoxin-induced lung inflammation in humans is not responsive to pioglitazone or zileuton, highlighting the challenge in translating anti-inflammatory drug efficacy results from murine models to humans. Trial registration ClinicalTrials.gov NCT01174056.
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18
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Pulmonary 18F-FDG uptake helps refine current risk stratification in idiopathic pulmonary fibrosis (IPF). Eur J Nucl Med Mol Imaging 2018; 45:806-815. [PMID: 29335764 PMCID: PMC5978900 DOI: 10.1007/s00259-017-3917-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/14/2017] [Indexed: 12/11/2022]
Abstract
Purpose There is a lack of prognostic biomarkers in idiopathic pulmonary fibrosis (IPF) patients. The objective of this study is to investigate the potential of 18F-FDG-PET/ CT to predict mortality in IPF. Methods A total of 113 IPF patients (93 males, 20 females, mean age ± SD: 70 ± 9 years) were prospectively recruited for 18F-FDG-PET/CT. The overall maximum pulmonary uptake of 18F-FDG (SUVmax), the minimum pulmonary uptake or background lung activity (SUVmin), and target-to-background (SUVmax/ SUVmin) ratio (TBR) were quantified using routine region-of-interest analysis. Kaplan–Meier analysis was used to identify associations of PET measurements with mortality. We also compared PET associations with IPF mortality with the established GAP (gender age and physiology) scoring system. Cox analysis assessed the independence of the significant PET measurement(s) from GAP score. We investigated synergisms between pulmonary 18F-FDG-PET measurements and GAP score for risk stratification in IPF patients. Results During a mean follow-up of 29 months, there were 54 deaths. The mean TBR ± SD was 5.6 ± 2.7. Mortality was associated with high pulmonary TBR (p = 0.009), low forced vital capacity (FVC; p = 0.001), low transfer factor (TLCO; p < 0.001), high GAP index (p = 0.003), and high GAP stage (p = 0.003). Stepwise forward-Wald–Cox analysis revealed that the pulmonary TBR was independent of GAP classification (p = 0.010). The median survival in IPF patients with a TBR < 4.9 was 71 months, whilst in those with TBR > 4.9 was 24 months. Combining PET data with GAP data (“PET modified GAP score”) refined the ability to predict mortality. Conclusions A high pulmonary TBR is independently associated with increased risk of mortality in IPF patients. Electronic supplementary material The online version of this article (10.1007/s00259-017-3917-8) contains supplementary material, which is available to authorized users.
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Cuplov V, Holman BF, McClelland J, Modat M, Hutton BF, Thielemans K. Issues in quantification of registered respiratory gated PET/CT in the lung. ACTA ACUST UNITED AC 2017; 63:015007. [DOI: 10.1088/1361-6560/aa950b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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20
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Bousse A, Manber R, Holman BF, Atkinson D, Arridge S, Ourselin S, Hutton BF, Thielemans K. Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation. Med Phys 2017; 44:2379-2390. [DOI: 10.1002/mp.12253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/01/2017] [Accepted: 03/21/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Alexandre Bousse
- Institute of Nuclear Medicine; University College London; London NW1 2BU UK
| | - Richard Manber
- Institute of Nuclear Medicine; University College London; London NW1 2BU UK
| | - Beverley F. Holman
- Institute of Nuclear Medicine; University College London; London NW1 2BU UK
| | - David Atkinson
- Centre for Medical Imaging; University College London; London NW1 2PG UK
| | - Simon Arridge
- Centre for Medical Image Computing; University College London; London WC1E 7JE UK
| | - Sébastien Ourselin
- Centre for Medical Image Computing; University College London; London WC1E 7JE UK
| | - Brian F. Hutton
- Institute of Nuclear Medicine; University College London; London NW1 2BU UK
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
| | - Kris Thielemans
- Institute of Nuclear Medicine; University College London; London NW1 2BU UK
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21
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Mérida I, Reilhac A, Redouté J, Heckemann RA, Costes N, Hammers A. Multi-atlas attenuation correction supports full quantification of static and dynamic brain PET data in PET-MR. Phys Med Biol 2017; 62:2834-2858. [PMID: 28181479 DOI: 10.1088/1361-6560/aa5f6c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Ching DJ, Gürsoy D. XDesign: an open-source software package for designing X-ray imaging phantoms and experiments. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:537-544. [PMID: 28244451 DOI: 10.1107/s1600577517001928] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
The development of new methods or utilization of current X-ray computed tomography methods is impeded by the substantial amount of expertise required to design an X-ray computed tomography experiment from beginning to end. In an attempt to make material models, data acquisition schemes and reconstruction algorithms more accessible to researchers lacking expertise in some of these areas, a software package is described here which can generate complex simulated phantoms and quantitatively evaluate new or existing data acquisition schemes and image reconstruction algorithms for targeted applications.
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Affiliation(s)
| | - Dogˇa Gürsoy
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
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23
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Chen DL, Cheriyan J, Chilvers ER, Choudhury G, Coello C, Connell M, Fisk M, Groves AM, Gunn RN, Holman BF, Hutton BF, Lee S, MacNee W, Mohan D, Parr D, Subramanian D, Tal-Singer R, Thielemans K, van Beek EJR, Vass L, Wellen JW, Wilkinson I, Wilson FJ. Quantification of Lung PET Images: Challenges and Opportunities. J Nucl Med 2017; 58:201-207. [PMID: 28082432 DOI: 10.2967/jnumed.116.184796] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/10/2017] [Indexed: 01/03/2023] Open
Abstract
Millions of people are affected by respiratory diseases, leading to a significant health burden globally. Because of the current insufficient knowledge of the underlying mechanisms that lead to the development and progression of respiratory diseases, treatment options remain limited. To overcome this limitation and understand the associated molecular changes, noninvasive imaging techniques such as PET and SPECT have been explored for biomarker development, with 18F-FDG PET imaging being the most studied. The quantification of pulmonary molecular imaging data remains challenging because of variations in tissue, air, blood, and water fractions within the lungs. The proportions of these components further differ depending on the lung disease. Therefore, different quantification approaches have been proposed to address these variabilities. However, no standardized approach has been developed to date. This article reviews the data evaluating 18F-FDG PET quantification approaches in lung diseases, focusing on methods to account for variations in lung components and the interpretation of the derived parameters. The diseases reviewed include acute respiratory distress syndrome, chronic obstructive pulmonary disease, and interstitial lung diseases such as idiopathic pulmonary fibrosis. Based on review of prior literature, ongoing research, and discussions among the authors, suggested considerations are presented to assist with the interpretation of the derived parameters from these approaches and the design of future studies.
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Affiliation(s)
- Delphine L Chen
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Joseph Cheriyan
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Edwin R Chilvers
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Gourab Choudhury
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Martin Connell
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Marie Fisk
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Ashley M Groves
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Roger N Gunn
- Imanova Ltd., London, United Kingdom.,Department of Medicine, Imperial College London, London, United Kingdom
| | - Beverley F Holman
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Sarah Lee
- Medical Image Analysis Consultant, London, United Kingdom
| | - William MacNee
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Divya Mohan
- Clinical Discovery, Respiratory Therapy Area Unit, GlaxoSmithKline R&D, King of Prussia, Pennsylvania
| | - David Parr
- University Hospitals Coventry and Warwickshire, Coventry, United Kingdom
| | | | - Ruth Tal-Singer
- Clinical Discovery, Respiratory Therapy Area Unit, GlaxoSmithKline R&D, King of Prussia, Pennsylvania
| | - Kris Thielemans
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Edwin J R van Beek
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Laurence Vass
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jeremy W Wellen
- Worldwide Research and Development, Pfizer, Inc., Cambridge, Massachusetts; and
| | - Ian Wilkinson
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Frederick J Wilson
- Experimental Medicine Imaging, GlaxoSmithKline, Stevenage, United Kingdom
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