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Karimipourfard M, Sina S, Mahani H, Alavi M, Yazdi M. Impact of deep learning-based multiorgan segmentation methods on patient-specific internal dosimetry in PET/CT imaging: A comparative study. J Appl Clin Med Phys 2024; 25:e14254. [PMID: 38214349 PMCID: PMC10860559 DOI: 10.1002/acm2.14254] [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: 08/27/2023] [Revised: 10/29/2023] [Accepted: 11/30/2023] [Indexed: 01/13/2024] Open
Abstract
PURPOSE Accurate and fast multiorgan segmentation is essential in image-based internal dosimetry in nuclear medicine. While conventional manual PET image segmentation is widely used, it suffers from both being time-consuming as well as subject to human error. This study exploited 2D and 3D deep learning (DL) models. Key organs in the trunk of the body were segmented and then used as a reference for networks. METHODS The pre-trained p2p-U-Net-GAN and HighRes3D architectures were fine-tuned with PET-only images as inputs. Additionally, the HighRes3D model was alternatively trained with PET/CT images. Evaluation metrics such as sensitivity (SEN), specificity (SPC), intersection over union (IoU), and Dice scores were considered to assess the performance of the networks. The impact of DL-assisted PET image segmentation methods was further assessed using the Monte Carlo (MC)-derived S-values to be used for internal dosimetry. RESULTS A fair comparison with manual low-dose CT-aided segmentation of the PET images was also conducted. Although both 2D and 3D models performed well, the HighRes3D offers superior performance with Dice scores higher than 0.90. Key evaluation metrics such as SEN, SPC, and IoU vary between 0.89-0.93, 0.98-0.99, and 0.87-0.89 intervals, respectively, indicating the encouraging performance of the models. The percentage differences between the manual and DL segmentation methods in the calculated S-values varied between 0.1% and 6% with a maximum attributed to the stomach. CONCLUSION The findings prove while the incorporation of anatomical information provided by the CT data offers superior performance in terms of Dice score, the performance of HighRes3D remains comparable without the extra CT channel. It is concluded that both proposed DL-based methods provide automated and fast segmentation of whole-body PET/CT images with promising evaluation metrics. Between them, the HighRes3D is more pronounced by providing better performance and can therefore be the method of choice for 18F-FDG-PET image segmentation.
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Affiliation(s)
| | - Sedigheh Sina
- Department of Ray‐Medical EngineeringShiraz UniversityShirazIran
- Radiation Research CenterShiraz UniversityShirazIran
| | - Hojjat Mahani
- Radiation Applications Research SchoolNuclear Science and Technology Research InstituteTehranIran
| | - Mehrosadat Alavi
- Department of Nuclear MedicineShiraz University of Medical SciencesShirazIran
| | - Mehran Yazdi
- School of Electrical and Computer EngineeringShiraz UniversityShirazIran
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Pan Y, Liu S, Zeng Y, Ye C, Qiao H, Song T, Lv H, Chan P, Lu J, Ma T. A Multi-Atlas-Based [18F]9-Fluoropropyl-(+)-Dihydrotetrabenazine Positron Emission Tomography Image Segmentation Method for Parkinson's Disease Quantification. Front Aging Neurosci 2022; 14:902169. [PMID: 35769601 PMCID: PMC9234266 DOI: 10.3389/fnagi.2022.902169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Objectives [18F]9-fluoropropyl-(+)-dihydrotetrabenazine ([18F]-FP-DTBZ) positron emission tomography (PET) provides reliable information for the diagnosis of Parkinson's disease (PD). In this study, we proposed a multi-atlas-based [18F]-FP-DTBZ PET image segmentation method for PD quantification assessment. Methods A total of 99 subjects from Xuanwu Hospital of Capital Medical University were included in this study, and both brain PET and magnetic resonance (MR) scans were conducted. Data from 20 subjects were used to generate atlases, based on which a multi-atlas-based [18F]-FP-DTBZ PET segmentation method was developed especially for striatum and its subregions. The proposed method was compared with the template-based method through striatal subregion parcellation performance and the standard uptake value ratio (SUVR) quantification accuracy. Discriminant analysis between healthy controls (HCs) and PD patients was further performed. Results Segmentation results of the multi-atlas-based method showed better consistency than the template-based method with the ground truth, yielding a dice coefficient of 0.81 over 0.73 on the full striatum. The SUVRs calculated by the multi-atlas-based method had an average interclass correlation coefficient (ICC) of 0.953 with the standardized result, whereas the template-based method only reached 0.815. The SUVRs of HCs were generally higher than that of patients with PD and showed significant differences in all of the striatal subregions (all p < 0.001). The median and posterior putamen performed best in discriminating patients with PD from HCs. Conclusion The proposed multi-atlas-based [18F]-FP-DTBZ PET image segmentation method achieved better performance than the template-based method, indicating great potential in improving accuracy and efficiency for PD diagnosis in clinical routine.
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Affiliation(s)
- Yiwei Pan
- Department of Electronic and Information Engineering, Harbin Institute of Technology at Shenzhen, Shenzhen, China
| | - Shuying Liu
- Department of Neurology and Neurobiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research (CIBR), Beijing, China
| | - Yao Zeng
- Department of Electronic and Information Engineering, Harbin Institute of Technology at Shenzhen, Shenzhen, China
| | - Chenfei Ye
- International Research Institute for Artificial Intelligence, Harbin Institute of Technology at Shenzhen, Shenzhen, China
| | - Hongwen Qiao
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Capital Medical University, Beijing, China
| | - Tianbing Song
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Capital Medical University, Beijing, China
| | - Haiyan Lv
- Mindsgo Life Science Shenzhen Co. Ltd., Shenzhen, China
| | - Piu Chan
- Department of Neurology and Neurobiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Jie Lu
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Capital Medical University, Beijing, China
| | - Ting Ma
- Department of Electronic and Information Engineering, Harbin Institute of Technology at Shenzhen, Shenzhen, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
- Peng Cheng Laboratory, Shenzhen, China
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Mehta NH, Sherbansky J, Kamer AR, Carare RO, Butler T, Rusinek H, Chiang GC, Li Y, Strauss S, Saint-Louis LA, Theise ND, Suss RA, Blennow K, Kaplitt M, de Leon MJ. The Brain-Nose Interface: A Potential Cerebrospinal Fluid Clearance Site in Humans. Front Physiol 2022; 12:769948. [PMID: 35058794 PMCID: PMC8764168 DOI: 10.3389/fphys.2021.769948] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/26/2021] [Indexed: 12/17/2022] Open
Abstract
The human brain functions at the center of a network of systems aimed at providing a structural and immunological layer of protection. The cerebrospinal fluid (CSF) maintains a physiological homeostasis that is of paramount importance to proper neurological activity. CSF is largely produced in the choroid plexus where it is continuous with the brain extracellular fluid and circulates through the ventricles. CSF movement through the central nervous system has been extensively explored. Across numerous animal species, the involvement of various drainage pathways in CSF, including arachnoid granulations, cranial nerves, perivascular pathways, and meningeal lymphatics, has been studied. Among these, there is a proposed CSF clearance route spanning the olfactory nerve and exiting the brain at the cribriform plate and entering lymphatics. While this pathway has been demonstrated in multiple animal species, evidence of a similar CSF egress mechanism involving the nasal cavity in humans remains poorly consolidated. This review will synthesize contemporary evidence surrounding CSF clearance at the nose-brain interface, examining across species this anatomical pathway, and its possible significance to human neurodegenerative disease. Our discussion of a bidirectional nasal pathway includes examination of the immune surveillance in the olfactory region protecting the brain. Overall, we expect that an expanded discussion of the brain-nose pathway and interactions with the environment will contribute to an improved understanding of neurodegenerative and infectious diseases, and potentially to novel prevention and treatment considerations.
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Affiliation(s)
- Neel H. Mehta
- Undergraduate Department of Biology, Cornell University, Ithaca, NY, United States
| | | | - Angela R. Kamer
- Department of Periodontology and Implant Dentistry, NYU College of Dentistry, New York, NY, United States
| | - Roxana O. Carare
- Department of Medicine, University of Southampton, Southampton, United Kingdom
| | - Tracy Butler
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
| | - Henry Rusinek
- Department of Radiology, NYU Langone Health, New York, NY, United States
| | - Gloria C. Chiang
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Yi Li
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
| | - Sara Strauss
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - L. A. Saint-Louis
- Department of Radiology, NYU Langone Health, New York, NY, United States
| | - Neil D. Theise
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, United States
| | - Richard A. Suss
- Division of Neuroradiology, Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kaj Blennow
- Clinical Neurochemistry Lab, Inst. of Neuroscience and Physiology, University of Gothenburg, Sahlgrenska University Hospital, Göteborg, Sweden
| | - Michael Kaplitt
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY, United States
| | - Mony J. de Leon
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
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Shoeibi A, Khodatars M, Jafari M, Moridian P, Rezaei M, Alizadehsani R, Khozeimeh F, Gorriz JM, Heras J, Panahiazar M, Nahavandi S, Acharya UR. Applications of deep learning techniques for automated multiple sclerosis detection using magnetic resonance imaging: A review. Comput Biol Med 2021; 136:104697. [PMID: 34358994 DOI: 10.1016/j.compbiomed.2021.104697] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 11/18/2022]
Abstract
Multiple Sclerosis (MS) is a type of brain disease which causes visual, sensory, and motor problems for people with a detrimental effect on the functioning of the nervous system. In order to diagnose MS, multiple screening methods have been proposed so far; among them, magnetic resonance imaging (MRI) has received considerable attention among physicians. MRI modalities provide physicians with fundamental information about the structure and function of the brain, which is crucial for the rapid diagnosis of MS lesions. Diagnosing MS using MRI is time-consuming, tedious, and prone to manual errors. Research on the implementation of computer aided diagnosis system (CADS) based on artificial intelligence (AI) to diagnose MS involves conventional machine learning and deep learning (DL) methods. In conventional machine learning, feature extraction, feature selection, and classification steps are carried out by using trial and error; on the contrary, these steps in DL are based on deep layers whose values are automatically learn. In this paper, a complete review of automated MS diagnosis methods performed using DL techniques with MRI neuroimaging modalities is provided. Initially, the steps involved in various CADS proposed using MRI modalities and DL techniques for MS diagnosis are investigated. The important preprocessing techniques employed in various works are analyzed. Most of the published papers on MS diagnosis using MRI modalities and DL are presented. The most significant challenges facing and future direction of automated diagnosis of MS using MRI modalities and DL techniques are also provided.
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Affiliation(s)
- Afshin Shoeibi
- Faculty of Electrical Engineering, Biomedical Data Acquisition Lab (BDAL), K. N. Toosi University of Technology, Tehran, Iran.
| | - Marjane Khodatars
- Faculty of Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
| | - Mahboobeh Jafari
- Electrical and Computer Engineering Faculty, Semnan University, Semnan, Iran
| | - Parisa Moridian
- Faculty of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Mitra Rezaei
- Electrical and Computer Engineering Dept., Tarbiat Modares University, Tehran, Iran
| | - Roohallah Alizadehsani
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Geelong, Australia
| | - Fahime Khozeimeh
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Geelong, Australia
| | - Juan Manuel Gorriz
- Department of Signal Theory, Networking and Communications, Universidad de Granada, Spain; Department of Psychiatry. University of Cambridge, UK
| | - Jónathan Heras
- Department of Mathematics and Computer Science, University of La Rioja, La Rioja, Spain
| | | | - Saeid Nahavandi
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Geelong, Australia
| | - U Rajendra Acharya
- Department of Biomedical Engineering, School of Science and Technology, Singapore University of Social Sciences, Singapore; Dept. of Electronics and Computer Engineering, Ngee Ann Polytechnic, 599489, Singapore; Department of Bioinformatics and Medical Engineering, Asia University, Taiwan
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Zeng T, Zheng J, Xia X, Chen X, Wang B, Zhang S, Chandler A, Cao T, Hu L, Chen Q, Chu X. Design and system evaluation of a dual-panel portable PET (DP-PET). EJNMMI Phys 2021; 8:47. [PMID: 34117943 PMCID: PMC8197684 DOI: 10.1186/s40658-021-00392-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/03/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Integrated whole-body PET/MR technology continues to mature and is now extensively used in clinical settings. However, due to the special design architecture, integrated whole-body PET/MR comes with a few inherent limitations. Firstly, whole-body PET/MR lacks sensitivity and resolution for focused organs. Secondly, broader clinical access of integrated PET/MR has been significantly restricted due to its prohibitively high cost. The MR-compatible PET insert is an independent and removable PET scanner which can be placed within an MRI bore. However, the mobility and configurability of all existing MR-compatible PET insert prototypes remain limited. METHODS An MR-compatible portable PET insert prototype, dual-panel portable PET (DP-PET), has been developed for simultaneous PET/MR imaging. Using SiPM, digital readout electronics, novel carbon fiber shielding, phase-change cooling, and MRI compatible battery power, DP-PET was designed to achieve high-sensitivity and high-resolution with compatibility with a clinical 3-T MRI scanner. A GPU-based reconstruction method with resolution modeling (RM) has been developed for the DP-PET reconstruction. We evaluated the system performance on PET resolution, sensitivity, image quality, and the PET/MR interference. RESULTS The initial results reveal that the DP-PET prototype worked as expected in the MRI bore and caused minimal compromise to the MRI image quality. The PET performance was measured to show a spatial resolution ≤ 2.5 mm (parallel to the detector panels), maximum sensitivity = 3.6% at the center of FOV, and energy resolution = 12.43%. MR pulsing introduces less than 2% variation to the PET performance measurement results. CONCLUSIONS We developed a MR-compatible PET insert prototype and performed several studies to begin to characterize the performance of the proposed DP-PET. The results showed that the proposed DP-PET performed well in the MRI bore and would cause little influence on the MRI images. The Derenzo phantom test showed that the proposed reconstruction method could obtain high-quality images using DP-PET.
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Affiliation(s)
- Tianyi Zeng
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiaxu Zheng
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Xinyuan Xia
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Xin Chen
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Beien Wang
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Shuangyue Zhang
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Adam Chandler
- United Imaging Healthcare, America, Houston, TX, 77054, USA
| | - Tuoyu Cao
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Lingzhi Hu
- United Imaging Healthcare, America, Houston, TX, 77054, USA.
| | - Qun Chen
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
| | - Xu Chu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
- Shanghai United Imaging Healthcare Co., Ltd., Shanghai, 201807, China
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Chen S, Gu Y, Yu H, Chen X, Cao T, Hu L, Shi H. NEMA NU2-2012 performance measurements of the United Imaging uPMR790: an integrated PET/MR system. Eur J Nucl Med Mol Imaging 2021; 48:1726-1735. [PMID: 33388972 DOI: 10.1007/s00259-020-05135-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE In this paper, we aimed to evaluate the positron emission tomography (PET) performance of, to the best of our knowledge, the third commercially available whole-body integrated PET/magnetic resonance (MR) system. METHODS The PET system performance was measured following the NEMA standards with and without simultaneous MR operation. PET spatial resolution, sensitivity, scatter fraction, count-rate performance, accuracy of count losses and random corrections, image quality, and time-of-flight (TOF) resolution were quantitatively evaluated. Clinical scans were acquired at the PET/MR system and compared with images acquired at a PET/CT with the same digital detector technology. RESULTS Measurement results of essential PET performance were reported in the form of MR idle (MR pulsing). The axial, radial, and tangential spatial resolutions were measured as 2.72 mm (2.73 mm), 2.86 mm (2.85 mm), and 2.81 mm (2.82 mm) FWHM, respectively, at 1 cm radial offset. The NECR peak was measured as 129.2 kcps (129.5 kcps) at 14.7 kBq mL-1 (14.2 kBq mL-1). The scatter fraction at NECR peak was 37.9% (36.5%), and the maximum slice error below NECR was 4.1% (4.5%). Contrast recovery coefficients ranged from 51.8% (52.3%) for 10 mm hot sphere to 87.3% (87.2%) for 37 mm cold sphere. TOF resolution at 5.3 kBq mL-1 was measured at 535 ps (540 ps). With point source, TOF was measured to be 474 ps (485 ps). Clinical scans revealed similar image quality from the PET/MR and the comparative PET/CT system. CONCLUSION The PET performance of the newly introduced integrated PET/MR system is not significantly affected by the simultaneous operation of an MR sequence (2-point DIXON sequence). Measurement results demonstrate comparable performance with other state-of-the-art PET/MR systems. The clinical benefits of high spatial resolution and long axial coverage remain to be further evaluated in specific clinical imaging applications.
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Affiliation(s)
- Shuguang Chen
- Zhongshan Hospital, Fudan University, 1609 Xietu Road, Shanghai, 200032, China.,Institute of Nuclear Medicine, Fudan University, Shanghai, China
| | - Yushen Gu
- Zhongshan Hospital, Fudan University, 1609 Xietu Road, Shanghai, 200032, China.,Institute of Nuclear Medicine, Fudan University, Shanghai, China
| | - Haojun Yu
- Zhongshan Hospital, Fudan University, 1609 Xietu Road, Shanghai, 200032, China.,Institute of Nuclear Medicine, Fudan University, Shanghai, China
| | - Xin Chen
- United Imaging Healthcare Co., Ltd., Shanghai, China
| | - Tuoyu Cao
- United Imaging Healthcare Co., Ltd., Shanghai, China
| | - Lingzhi Hu
- United Imaging Healthcare Co., Ltd., Shanghai, China
| | - Hongcheng Shi
- Zhongshan Hospital, Fudan University, 1609 Xietu Road, Shanghai, 200032, China. .,Institute of Nuclear Medicine, Fudan University, Shanghai, China.
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Reich CM, Sattler B, Jochimsen TH, Unger M, Melzer L, Landgraf L, Barthel H, Sabri O, Melzer A. Practical setting and potential applications of interventions guided by PET/MRI. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF RADIOPHARMACEUTICAL CHEMISTRY AND BIOLOGY 2020; 65:43-50. [PMID: 33300750 DOI: 10.23736/s1824-4785.20.03293-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multimodality imaging has emerged from a vision thirty years ago to routine clinical use today. Positron emission tomography (PET)/magnetic resonance imaging (MRI) is still relatively new in this arena and particularly suitable for clinical research and technical development. PET/MRI-guidance for interventions opens up opportunities for novel treatments but at the same time demands certain technical and organizational requirements to be fulfilled. In this work, we aimed to demonstrate a practical setting and potential application of PET/MRI guidance of interventional procedures. The superior quantitative physiologic information of PET, the various unique imaging characteristics of MRI, and the reduced radiation exposure are the most relevant advantages of this technique. As a noninvasive interventional tool, focused ultrasound (FUS) ablation of tumor cells would benefit from PET/MRI for diagnostics, treatment planning and intervention. Yet, technical limitations might impeed preclinical research, given that PET/MRI sites are per se not designed as interventional suites. Nonetheless, several approaches have been offered in the past years to upgrade MRI suites for interventional purposes. Taking advantage of state of the art and easy-to-use technology it is possible to create a supporting infrastructure that is suitable for broad preclinical adaption. Several aspects are to be addressed, including remote control of the imaging system, display of the imaging results, communication technology, and implementation of additional devices such as a FUS platform and an MR-compatible robotic system for positioning of the FUS equipment. Feasibility could be demostrated with an examplary experimental setup for interventional PET/MRI. Most PET/MRI sites could allow for interventions with just a few add-ons and modifications, such as comunication, in room image display and sytems control. By unlocking this feature, and driving preclinical research in interventional PET/MRI, translation of the protocol and methodology into clinical settings seems feasible.
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Affiliation(s)
- C Martin Reich
- Innovation Center Computer Assisted Surgery, University of Leipzig, Leipzig, Germany
| | - Bernhard Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany -
| | - Thies H Jochimsen
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Michael Unger
- Innovation Center Computer Assisted Surgery, University of Leipzig, Leipzig, Germany
| | - Leon Melzer
- Innovation Center Computer Assisted Surgery, University of Leipzig, Leipzig, Germany
| | - Lisa Landgraf
- Innovation Center Computer Assisted Surgery, University of Leipzig, Leipzig, Germany
| | - Henryk Barthel
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Andreas Melzer
- Innovation Center Computer Assisted Surgery, University of Leipzig, Leipzig, Germany.,Institute for Medical Science and Technology IMSaT, University Dundee, Scotland, UK
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Almost 10 years of PET/MR attenuation correction: the effect on lesion quantification with PSMA: clinical evaluation on 200 prostate cancer patients. Eur J Nucl Med Mol Imaging 2020; 48:543-553. [PMID: 32725538 PMCID: PMC7835314 DOI: 10.1007/s00259-020-04957-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/08/2020] [Indexed: 01/28/2023]
Abstract
Purpose After a decade of PET/MR, the case of attenuation correction (AC) remains open. The initial four-compartment (air, water, fat, soft tissue) Dixon-based AC scheme has since been expanded with several features, the latest being MR field-of-view extension and a bone atlas. As this potentially changes quantification, we evaluated the impact of these features in PET AC in prostate cancer patients. Methods Two hundred prostate cancer patients were examined with either 18F- or 68Ga-prostate-specific membrane antigen (PSMA) PET/MR. Qualitative and quantitative analysis (SUVmean, SUVmax, correlation, and statistical significance) was performed on images reconstructed using different AC schemes: Dixon, Dixon+MLAA, Dixon+HUGE, and Dixon+HUGE+bones for 18F-PSMA data; Dixon and Dixon+bones for 68Ga-PSMA data. Uptakes were compared using linear regression against standard Dixon. Results High correlation and no visually perceivable differences between all evaluated methods (r > 0.996) were found. The mean relative difference in lesion uptake of 18F-PSMA and 68Ga-PSMA remained, respectively, within 4% and 3% in soft tissue, and within 10% and 9% in bones for all evaluated methods. Bone registration errors were detected, causing mean uptake change of 5% in affected lesions. Conclusions Based on these results and the encountered bone atlas registration inaccuracy, we deduce that including bones and extending the MR field-of-view did not introduce clinically significant differences in PSMA diagnostic accuracy and tracer uptake quantification in prostate cancer pelvic lesions, facilitating the analysis of serial studies respectively. However, in the absence of ground truth data, we advise against atlas-based methods when comparing serial scans for bone lesions.
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Coenen HH, Ermert J. Expanding PET-applications in life sciences with positron-emitters beyond fluorine-18. Nucl Med Biol 2020; 92:241-269. [PMID: 32900582 DOI: 10.1016/j.nucmedbio.2020.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/09/2020] [Indexed: 12/20/2022]
Abstract
Positron-emission-tomography (PET) has become an indispensable diagnostic tool in modern nuclear medicine. Its outstanding molecular imaging features allow repetitive studies on one individual and with high sensitivity, though no interference. Rather few positron-emitters with near favourable physical properties, i.e. carbon-11 and fluorine-18, furnished most studies in the beginning, preferably if covalently bound as isotopic label of small molecules. With the advancement of PET-devices the scope of in vivo research in life sciences and especially that of medical applications expanded, and other than "standard" PET-nuclides received increasing significance, like the radiometals copper-64 and gallium-68. Especially during the last decades, positron-emitters of other chemical elements have gotten into the focus of interest, concomitant with the technical advancements in imaging and radionuclide production. With known nuclear imaging properties and main production methods of emerging positron-emitters their usefulness for medical application is promising and even proven for several ones already. Unfortunate decay properties could be corrected for, and β+-emitters, especially with a longer half-life, provided new possibilities for application where slower processes are of importance. Further on, (bio)chemical features of positron-emitters of other elements, among there many metals, not only expanded the field of classical clinical investigations, but also opened up new fields of application. Appropriately labelled peptides, proteins and nanoparticles lend itself as newer probes for PET-imaging, e.g. in theragnostic or PET/MR hybrid imaging. Furthermore, the potential of non-destructive in-vivo imaging with positron-emission-tomography directs the view on further areas of life sciences. Thus, exploiting the excellent methodology for basic research on molecular biochemical functions and processes is increasingly encouraged as well in areas outside of health, such as plant and environmental sciences.
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Affiliation(s)
- Heinz H Coenen
- Institut für Neurowissenschaften und Medizin, INM-5, Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
| | - Johannes Ermert
- Institut für Neurowissenschaften und Medizin, INM-5, Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
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Ruan W, Sun X, Hu X, Liu F, Hu F, Guo J, Zhang Y, Lan X. Regional SUV quantification in hybrid PET/MR, a comparison of two atlas-based automatic brain segmentation methods. EJNMMI Res 2020; 10:60. [PMID: 32514906 PMCID: PMC7280441 DOI: 10.1186/s13550-020-00648-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 05/21/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Quantitative analysis of brain positron-emission tomography (PET) depends on structural segmentation, which can be time-consuming and operator-dependent when performed manually. Previous automatic segmentation usually registered subjects' images onto an atlas template (defined as RSIAT here) for group analysis, which changed the individuals' images and probably affected regional PET segmentation. In contrast, we could register atlas template to subjects' images (RATSI), which created an individual atlas template and may be more accurate for PET segmentation. We segmented two representative brain areas in twenty Parkinson disease (PD) and eight multiple system atrophy (MSA) patients performed in hybrid positron-emission tomography/magnetic resonance imaging (PET/MR). The segmentation accuracy was evaluated using the Dice coefficient (DC) and Hausdorff distance (HD), and the standardized uptake value (SUV) measurements of these two automatic segmentation methods were compared, using manual segmentation as a reference. RESULTS The DC of RATSI increased, and the HD decreased significantly (P < 0.05) compared with the RSIAT in PD, while the results of one-way analysis of variance (ANOVA) found no significant differences in the SUVmean and SUVmax among the two automatic and the manual segmentation methods. Further, RATSI was used to compare regional differences in cerebral metabolism pattern between PD and MSA patients. The SUVmean in the segmented cerebellar gray matter for the MSA group was significantly lower compared with the PD group (P < 0.05), which is consistent with previous reports. CONCLUSION The RATSI was more accurate for the caudate nucleus and putamen automatic segmentation and can be used for regional PET analysis in hybrid PET/MR.
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Affiliation(s)
- Weiwei Ruan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Xun Sun
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Xuehan Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Fang Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Fan Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | | | - Yongxue Zhang
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Xiaoli Lan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China.
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China.
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11
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Zhang T, Shi M. Multi-modal neuroimaging feature fusion for diagnosis of Alzheimer's disease. J Neurosci Methods 2020; 341:108795. [PMID: 32446943 DOI: 10.1016/j.jneumeth.2020.108795] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Compared with single-modal neuroimages classification of AD, multi-modal classification can achieve better performance by fusing different information. Exploring synergy among various multi-modal neuroimages is contributed to identifying the pathological process of neurological disorders. However, it is still problematic to effectively exploit multi-modal information since the lack of an effective fusion method. NEW METHOD In this paper, we propose a deep multi-modal fusion network based on the attention mechanism, which can selectively extract features from MRI and PET branches and suppress irrelevant information. In the attention model, the fusion ratio of each modality is assigned automatically according to the importance of the data. A hierarchical fusion method is adopted to ensure the effectiveness of Multi-modal Fusion. RESULTS Evaluating the model on the ADNI dataset, the experimental results show that it outperforms the state-of-the-art methods. In particular, the final classification results of the NC/AD, SMCI/PMCI and Four-Class are 95.21 %, 89.79 %, and 86.15 %, respectively. COMPARISON WITH EXISTING METHODS Different from the early fusion and the late fusion, the hierarchical fusion method contributes to learning the synergy between the multi-modal data. Compared with some other prominent algorithms, the attention model enables our network to focus on the regions of interest and effectively fuse the multi-modal data. CONCLUSION Benefit from the hierarchical structure with attention model, the proposed network is capable of exploiting low-level and high-level features extracted from the multi-modal data and improving the accuracy of AD diagnosis. Results show its promising performance.
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Affiliation(s)
- Tao Zhang
- School of Electronic and Information Engineering, Tianjin University, 300387, Tianjin, China
| | - Mingyang Shi
- School of Electronic and Information Engineering, Tianjin University, 300387, Tianjin, China.
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12
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Comparison of FDG PET/MRI and FDG PET/CT in Pediatric Oncology in Terms of Anatomic Correlation of FDG-positive Lesions. J Pediatr Hematol Oncol 2019; 41:542-550. [PMID: 30933019 DOI: 10.1097/mph.0000000000001465] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The aims of our study were to compare F-18 fluorodeoxyglucose (FDG) positron-emission tomography/magnetic resonance imaging (PET/MRI) and PET/computed tomography (CT) in pediatric oncology patients in terms of anatomic correlation of FDG-positive lesions, and also to compare diffusion-weighted imaging (DWI) with PET to assess the correlation between apparent diffusion coefficient (ADC) values and standardized uptake value (SUV). Sequential PET/CT and PET/MRI images and/or whole-body DWI and ADC mapping in 34 pediatric patients were retrospectively analyzed. FDG-positive lesions were visually scored for CT, T1-weighted, T2-weighted, and DWI images separately in terms of anatomic correlation of FDG-avid lesions. Correlation analysis was performed for SUV parameters and ADC values. Among 47 FDG-positive lesions identified concurrently on PET/CT and PET/MRI, 37 were positive on CT and 46 were positive on at least one MRI sequence (P=0.012). Among 32 FDG-positive lesions for which DWI were available, 31 could be clearly depicted on DWI, resulting in significant difference compared with CT alone in the detection of FDG-positive lesions. No correlation was found between ADC and SUV. FDG PET/MRI exhibits better performance than PET/CT in terms of anatomic correlation of FDG-avid lesions. Therefore, PET/MRI may be more advantageous than PET/CT, not only due to reduced ionizing radiation dose but also for a better depiction of FDG-avid lesions in pediatric PET imaging.
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13
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Witoszynskyj S, Andrzejewski P, Georg D, Hacker M, Nyholm T, Rausch I, Knäusl B. Attenuation correction of a flat table top for radiation therapy in hybrid PET/MR using CT- and 68Ge/ 68Ga transmission scan-based μ-maps. Phys Med 2019; 65:76-83. [PMID: 31437602 DOI: 10.1016/j.ejmp.2019.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 12/28/2022] Open
Abstract
Hybrid PET/MR offers new opportunities in radiation oncology for tissue/tumour characterisation and response assessment. Attenuation correction (AC) is an important issue especially in the presence of immobilization devices and flat table tops (FTT). The goal of this study was to compare two methods of AC using CT- and 68Ge/68Ga transmission scan-based attenuation maps (μ-maps) for a custom-designed FTT. Measurements were performed in the mMR PET/MR and TrueV PET/CT Biograph Siemens scanners with three different phantoms, namely the Siemens MR-QA, a cubic canister and the NEMA IEC body phantom. The study revealed that the MR image quality is not hampered by the presence of the FTT. For cubic canister applying the scanner's inherent AC alone resulted in inaccuracies in PET images, with up to -4.0% underestimation of the activity. The mean NEMA sphere activity measurements without FTT, agreed within 3.5% with the respective inserted activity. Placing the FTT in the PET/MR scanner resulted in a difference to the injected activity of 4.5% when the table was not corrected for. By introducing the μ-maps the discrepancy between the used activity and the measurements decreased down to 2.6%. To improve the AC of the FTT the creation of a dedicated μ-map was necessary while the CT-based μ-map performed equally good as the source transmission scan-based one.
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Affiliation(s)
- Stephan Witoszynskyj
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Piotr Andrzejewski
- Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Dietmar Georg
- Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Tufve Nyholm
- Department of Radiation Sciences, Umeå University, SE-90187 Umeå, Sweden
| | - Ivo Rausch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Barbara Knäusl
- Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria.
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14
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Ryan JL, Aaron VD, Sims JB. PET/MRI vs PET/CT in Head and Neck Imaging: When, Why, and How? Semin Ultrasound CT MR 2019; 40:376-390. [PMID: 31635765 DOI: 10.1053/j.sult.2019.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The increasing availability of hybrid PET/MRI systems has led to a breadth of new publications and opportunities for use of PET/MRI. While PET/CT has been a valuable tool for oncologic staging, including head and neck malignancy, there are several theoretical and practical advantages a PET/MRI system would have over PET/CT in head and neck imaging. This review article discusses the established role of PET/CT, early evidence for the role of PET/MRI, and protocol considerations for both PET/CT and PET/MRI as they apply to head and neck imaging.
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Affiliation(s)
- Joshua L Ryan
- Indiana University School of Medicine, Indianapolis, IN.
| | | | - Justin B Sims
- Indiana University School of Medicine, Indianapolis, IN
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15
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Sjöholm T, Ekström S, Strand R, Ahlström H, Lind L, Malmberg F, Kullberg J. A whole-body FDG PET/MR atlas for multiparametric voxel-based analysis. Sci Rep 2019; 9:6158. [PMID: 30992502 PMCID: PMC6467986 DOI: 10.1038/s41598-019-42613-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 04/04/2019] [Indexed: 01/12/2023] Open
Abstract
Quantitative multiparametric imaging is a potential key application for Positron Emission Tomography/Magnetic Resonance (PET/MR) hybrid imaging. To enable objective and automatic voxel-based multiparametric analysis in whole-body applications, the purpose of this study was to develop a multimodality whole-body atlas of functional 18F-fluorodeoxyglucose (FDG) PET and anatomical fat-water MR data of adults. Image registration was used to transform PET/MR images of healthy control subjects into male and female reference spaces, producing a fat-water MR, local tissue volume and FDG PET whole-body normal atlas consisting of 12 male (66.6 ± 6.3 years) and 15 female (69.5 ± 3.6 years) subjects. Manual segmentations of tissues and organs in the male and female reference spaces confirmed that the atlas contained adequate physiological and anatomical values. The atlas was applied in two anomaly detection tasks as proof of concept. The first task automatically detected anomalies in two subjects with suspected malignant disease using FDG data. The second task successfully detected abnormal liver fat infiltration in one subject using fat fraction data.
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Affiliation(s)
- Therese Sjöholm
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
| | - Simon Ekström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Robin Strand
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Håkan Ahlström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical AB, Mölndal, Sweden
| | - Lars Lind
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Filip Malmberg
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Joel Kullberg
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical AB, Mölndal, Sweden
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16
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Tate CJ, Mollee PN, Miles KA. Combination bone marrow imaging using positron emission tomography (PET)-MRI in plasma cell dyscrasias: correlation with prognostic laboratory values and clinicopathological diagnosis. BJR Open 2019; 1:20180020. [PMID: 33178915 PMCID: PMC7592407 DOI: 10.1259/bjro.20180020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/13/2018] [Accepted: 01/10/2019] [Indexed: 02/05/2023] Open
Abstract
Objective This prospective observational study of positron emission tomography (PET)-MRI findings in 16 consecutive newly diagnosed patients with a plasma cell dyscrasia describes and compares MRI-detected myeloma lesions with 18F-fludeoxyglucose PET-avid myeloma lesions, and correlates quantitative imaging findings to a range of biochemical and prognostic parameters. Methods Simultaneously acquired whole body PET and MRI images were evaluated qualitatively for the presence of focal or generalised abnormalities of bone marrow (BM) on either modality. Quantitative analysis comprised mean standardised uptake values (SUVmean) and fractional water content of the BM measured from PET and chemical shift MRI images of the second to fourth lumbar vertebrae. Results Final diagnoses comprised symptomatic myeloma (n = 10), asymptomatic myeloma (n = 4) and monoclonal gammopathy of uncertain significance (n = 2). 8/10 patients with symptomatic myeloma demonstrated BM abnormalities on qualitative assessment of MRI compared to 4/10 on PET. BM SUVmean inversely correlated with serum albumin (r = 0.57, p = 0.017). BM water fraction correlated with trephine cellularity and blood platelet count (r = 0.78, p = 0.00039 and r = 0.61, p = 0.0013 respectively). BM water fraction correlated with SUVmean in patients with low plasma cell burden (r = 0.91, p = 0.0015) but not in patients with high plasma cell burden (r = 0.18, p = 0.61). Conclusion PET-MRI shows promise in both morphological and functional multiparametric quantitative assessment of myeloma. Advances in knowledge For the first time, multiparametric imaging in myeloma has been shown to predict BM abnormalities and correlate with known biochemical prognostic markers, moving PET-MRI beyond simple diagnostic applications into potential prognostic and treatment selection applications.
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Affiliation(s)
- Courtney J Tate
- Princess Alexandra Hospital, Royal Brisbane and Women's Hospital, University of Queensland, QLD, Australia
| | - Peter N Mollee
- Institute of Nuclear Medicine, University College London, QLD, Australia
| | - Kenneth A Miles
- Princess Alexandra Hospital, University of Queensland, QLD, Australia
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17
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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: 34] [Impact Index Per Article: 5.7] [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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18
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Bailey DL, Pichler BJ, Gückel B, Antoch G, Barthel H, Bhujwalla ZM, Biskup S, Biswal S, Bitzer M, Boellaard R, Braren RF, Brendle C, Brindle K, Chiti A, la Fougère C, Gillies R, Goh V, Goyen M, Hacker M, Heukamp L, Knudsen GM, Krackhardt AM, Law I, Morris JC, Nikolaou K, Nuyts J, Ordonez AA, Pantel K, Quick HH, Riklund K, Sabri O, Sattler B, Troost EGC, Zaiss M, Zender L, Beyer T. Combined PET/MRI: Global Warming-Summary Report of the 6th International Workshop on PET/MRI, March 27-29, 2017, Tübingen, Germany. Mol Imaging Biol 2018; 20:4-20. [PMID: 28971346 PMCID: PMC5775351 DOI: 10.1007/s11307-017-1123-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.
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Affiliation(s)
- D L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, and Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - B J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard-Karls-Universität, Tübingen, Germany
| | - B Gückel
- Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany
| | - G Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225, Dusseldorf, Germany
| | - H Barthel
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Z M Bhujwalla
- Division of Cancer Imaging Research, Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - S Biskup
- Praxis für Humangenetik Tübingen, Paul-Ehrlich-Str. 23, 72076, Tübingen, Germany
| | - S Biswal
- Molecular Imaging Program at Stanford (MIPS) and Bio-X, Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - M Bitzer
- Department of Internal Medicine I, Eberhard-Karls University, Tübingen, Germany
| | - R Boellaard
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - R F Braren
- Institute of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - C Brendle
- Diagnostic and Interventional Neuroradiology, Department of Radiology, Eberhard Karls University, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - K Brindle
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - A Chiti
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Department of Nuclear Medicine, Humanitas Research Hospital, Milan, Italy
| | - C la Fougère
- Department of Radiology, Nuclear Medicine and Clinical Molecular Imaging, Eberhard-Karls-Universität, Tübingen, Germany
| | - R Gillies
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33621, USA
| | - V Goh
- Cancer Imaging, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
- Department of Radiology, Guy's & St Thomas' Hospitals London, London, UK
| | - M Goyen
- GE Healthcare GmbH, Beethovenstrasse 239, Solingen, Germany
| | - M Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | | | - G M Knudsen
- Neurobiology Research Unit, Rigshospitalet and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A M Krackhardt
- III. Medical Department, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - I Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - J C Morris
- Knight Alzheimer Disease Research Center, Washington University School of Medicine, St Louis, MO, USA
| | - K Nikolaou
- Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany
| | - J Nuyts
- Nuclear Medicine & Molecular Imaging, KU Leuven, Leuven, Belgium
| | - A A Ordonez
- Department of Pediatrics, Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - K Pantel
- Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - H H Quick
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
- Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Essen, Germany
| | - K Riklund
- Department of Radiation Sciences, Umea University, Umea, Sweden
| | - O Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - B Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - E G C Troost
- OncoRay-National Center for Radiation Research in Oncology, Dresden, Germany
- Institute of Radiooncology-OncoRay, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Department of Radiotherapy, University Hospital Carl Gustav Carus and Medical Faculty of Technische Universität Dresden, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, Dresden, Germany
| | - M Zaiss
- High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - L Zender
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany
| | - Thomas Beyer
- QIMP Group, Center for Medical Physics and Biomedical Engineering General Hospital Vienna, Medical University Vienna, 4L, Waehringer Guertel 18-20, 1090, Vienna, Austria.
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19
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Cabello J, Ziegler SI. Advances in PET/MR instrumentation and image reconstruction. Br J Radiol 2018; 91:20160363. [PMID: 27376170 PMCID: PMC5966194 DOI: 10.1259/bjr.20160363] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 06/26/2016] [Accepted: 06/29/2016] [Indexed: 12/15/2022] Open
Abstract
The combination of positron emission tomography (PET) and MRI has attracted the attention of researchers in the past approximately 20 years in small-animal imaging and more recently in clinical research. The combination of PET/MRI allows researchers to explore clinical and research questions in a wide number of fields, some of which are briefly mentioned here. An important number of groups have developed different concepts to tackle the problems that PET instrumentation poses to the exposition of electromagnetic fields. We have described most of these research developments in preclinical and clinical experiments, including the few commercial scanners available. From the software perspective, an important number of algorithms have been developed to address the attenuation correction issue and to exploit the possibility that MRI provides for motion correction and quantitative image reconstruction, especially parametric modelling of radiopharmaceutical kinetics. In this work, we give an overview of some exemplar applications of simultaneous PET/MRI, together with technological hardware and software developments.
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Affiliation(s)
- Jorge Cabello
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sibylle I Ziegler
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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20
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Abstract
BACKGROUND The (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG-PET/CT) procedure is a cornerstone in the diagnostics of head and neck cancers. Several years ago PET-magnetic resonance imaging (PET/MRI) also became available as an alternative hybrid multimodal imaging method. OBJECTIVE Does PET/MRI have advantages over PET/CT in the diagnostics of head and neck cancers? MATERIAL AND METHODS The diagnostic accuracy of the standard imaging methods CT, MRI and PET/CT is depicted according to currently available meta-analyses and studies concerning the use of PET/MRI for these indications are summarized. RESULTS In all studies published up to now PET/MRI did not show superiority regarding the diagnostic accuracy in head and neck cancers; however, there is some evidence that in the future PET/MRI can contribute to tumor characterization and possibly be used to predict tumor response to therapy with the use of multiparametric imaging. CONCLUSION Currently, (18)F-FDG-PET/CT is not outperformed by PET/MRI in the diagnostics of head and neck cancers. The additive value of PET/MRI due to the use of multiparametric imaging needs to be investigated in future research.
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Wetter A, Grueneisen J, Umutlu L. PET/MR imaging of pelvic malignancies. Eur J Radiol 2017; 94:A44-A51. [DOI: 10.1016/j.ejrad.2017.02.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 01/03/2023]
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22
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Eiber M, Rauscher I, Souvatzoglou M, Maurer T, Schwaiger M, Holzapfel K, Beer AJ. Prospective head-to-head comparison of 11C-choline-PET/MR and 11C-choline-PET/CT for restaging of biochemical recurrent prostate cancer. Eur J Nucl Med Mol Imaging 2017; 44:2179-2188. [PMID: 28803358 DOI: 10.1007/s00259-017-3797-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/27/2017] [Indexed: 01/09/2023]
Abstract
PURPOSE Whole-body integrated 11C-choline PET/MR might provide advantages compared to 11C-choline PET/CT for restaging of prostate cancer (PC) due to the high soft-tissue contrast and the use of multiparametric MRI, especially for detection of local recurrence and bone metastases. MATERIALS AND METHODS Ninety-four patients with recurrent PC underwent a single-injection/dual-imaging protocol with contrast-enhanced PET/CT followed by fully diagnostic PET/MR. Imaging datasets were read separately by two reader teams (team 1 and 2) assessing the presence of local recurrence, lymph node and bone metastases in predefined regions using a five-point scale. Detection rates were calculated. The diagnostic performance of PET/CT vs. PET/MR was compared using ROC analysis. Inter-observer and inter-modality variability, radiation exposure, and mean imaging time were evaluated. Clinical follow-up, imaging, and/or histopathology served as standard of reference (SOR). RESULTS Seventy-five patients qualified for the final image analysis. A total of 188 regions were regarded as positive: local recurrence in 37 patients, 87 regions with lymph node metastases, and 64 regions with bone metastases. Mean detection rate between both readers teams for PET/MR was 84.7% compared to 77.3% for PET/CT (p > 0.05). Local recurrence was identified significantly more often in PET/MR compared to PET/CT by team 1. Lymph node and bone metastases were identified significantly more often in PET/CT compared to PET/MR by both teams. However, this difference was not present in the subgroup of patients with PSA values ≤2 ng/ml. Inter-modality and inter-observer agreement (K > 0.6) was moderate to substantial for nearly all categories. Mean reduction of radiation exposure for PET/MR compared to PET/CT was 79.7% (range, 72.6-86.2%). Mean imaging time for PET/CT was substantially lower (18.4 ± 0.7 min) compared to PET/MR (50.4 ± 7.9 min). CONCLUSIONS 11C-choline PET/MR is a robust imaging modality for restaging biochemical recurrent PC and interpretations between different readers are consistent. It provides a higher diagnostic value for detecting local recurrence compared to PET/CT with the advantage of substantial dose reduction. Drawbacks of PET/MR are a substantially longer imaging time and a slight inferiority in detecting bone and lymph node metastases in patients with PSA values >2 ng/ml. Thus, we suggest the use of 11C-choline PET/MR especially for patients with low (≤2 ng/ml) PSA values, whereas PET/CT is preferable in the subgroup with higher PSA values.
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Affiliation(s)
- Matthias Eiber
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany.,Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, USA
| | - Isabel Rauscher
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany.
| | - Michael Souvatzoglou
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany
| | - Tobias Maurer
- Department of Urology, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany
| | - Markus Schwaiger
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany
| | - Konstantin Holzapfel
- Department of Radiology, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany
| | - Ambros J Beer
- Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany.,Department of Nuclear Medicine, Ulm University, Albert-Einstein-Allee 23, 89081, Ulm, Germany
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23
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Ladefoged CN, Andersen FL, Kjær A, Højgaard L, Law I. RESOLUTE PET/MRI Attenuation Correction for O-(2- 18F-fluoroethyl)-L-tyrosine (FET) in Brain Tumor Patients with Metal Implants. Front Neurosci 2017; 11:453. [PMID: 28848379 PMCID: PMC5554515 DOI: 10.3389/fnins.2017.00453] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023] Open
Abstract
Aim: Positron emission tomography (PET) imaging is a useful tool for assisting in correct differentiation of tumor progression from reactive changes, and the radiolabeled amino acid analog tracer O-(2-18F-fluoroethyl)-L-tyrosine (FET)-PET is amongst the most frequently used. The FET-PET images need to be quantitatively correct in order to be used clinically, which require accurate attenuation correction (AC) in PET/MRI. The aim of this study was to evaluate the use of the subject-specific MR-derived AC method RESOLUTE in post-operative brain tumor patients. Methods: We analyzed 51 post-operative brain tumor patients (68 examinations, 200 MBq [18F]-FET) investigated in a PET/MRI scanner. MR-AC maps were acquired using: (1) the Dixon water fat separation sequence, (2) the ultra short echo time (UTE) sequences, (3) calculated using our new RESOLUTE methodology, and (4) a same day low-dose CT used as reference “gold standard.” For each subject and each AC method the tumor was delineated by isocontouring tracer uptake above a tumor(T)-to-brain background (B) activity ratio of 1.6. We measured B, tumor mean and maximal activity (TMEAN, TMAX), biological tumor volume (BTV), and calculated the clinical metrics TMEAN/B and TMAX/B. Results: When using RESOLUTE 5/68 studies did not meet our predefined acceptance criteria of TMAX/B difference to CT-AC < ±0.1 or 5%, TMEAN/B < ±0.05 or 5%, and BTV < ±2 mL or 10%. In total, 46/68 studies failed our acceptance criteria using Dixon, and 26/68 using UTE. The 95% limits of agreement for TMAX/B was for RESOLUTE (−3%; 4%), Dixon (−9%; 16%), and UTE (−7%; 10%). The absolute error when measuring BTV was 0.7 ± 1.9 mL (N.S) with RESOLUTE, 5.3 ± 10 mL using Dixon, and 1.7 ± 3.7 mL using UTE. RESOLUTE performed best in the identification of the location of peak activity and in brain tumor follow-up monitoring using clinical FET PET metrics. Conclusions: Overall, we found RESOLUTE to be the AC method that most robustly reproduced the CT-AC clinical metrics per se, during follow-up, and when interpreted into defined clinical use cut-off criteria and into the patient history. RESOLUTE is especially suitable for brain tumor patients, as these often present with distorted anatomy where other methods based on atlas/template information might fail.
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Affiliation(s)
- Claes N Ladefoged
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of CopenhagenCopenhagen, Denmark
| | - Flemming L Andersen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of CopenhagenCopenhagen, Denmark
| | - Andreas Kjær
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of CopenhagenCopenhagen, Denmark
| | - Liselotte Højgaard
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of CopenhagenCopenhagen, Denmark
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of CopenhagenCopenhagen, Denmark
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24
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Plaque microvascularization and permeability: Key players in atherogenesis and plaque rupture. Atherosclerosis 2017; 263:320-321. [PMID: 28673479 DOI: 10.1016/j.atherosclerosis.2017.06.915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 06/20/2017] [Indexed: 12/29/2022]
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25
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Lee BJ, Watkins RD, Chang CM, Levin CS. Low eddy current RF shielding enclosure designs for 3T MR applications. Magn Reson Med 2017; 79:1745-1752. [PMID: 28585334 DOI: 10.1002/mrm.26766] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/14/2017] [Accepted: 05/03/2017] [Indexed: 12/30/2022]
Abstract
PURPOSE Magnetic resonance-compatible medical devices operate within the MR environment while benefitting from the superior anatomic information of MRI. Avoiding electromagnetic interference between such instrumentation and the MR system is crucial. In this work, various shielding configurations for positron emission tomography (PET) detectors were studied and analyzed regarding radiofrequency (RF) shielding effectiveness and gradient-induced eddy current performances. However, the results of this work apply to shielding considerations for any MR-compatible devices. METHODS Six shielding enclosure configurations with various thicknesses, patterns, and materials were designed: solid and segmented copper, phosphor bronze mesh (PBM), and carbon fiber composite (CFC). A series of tests was performed on RF shielding effectiveness and the gradient-induced eddy current. RESULTS For the shielding effectiveness, the solid copper with various thickness and PBM configurations yield significantly better shielding effectiveness (>15 dB) compared with CFC and segmented configurations. For the gradient-induced eddy current performance, the solid copper shielding configurations with different thicknesses showed significantly worse results, up to a factor of 3.89 dB, compared with the segmented copper, PBM, and the CFC configurations. CONCLUSIONS We evaluated the RF shielding effectiveness and the gradient-induced eddy current artifacts of several shielding designs, and only the PBM showed positive outcomes for both aspects. Magn Reson Med 79:1745-1752, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Brian J Lee
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Ronald D Watkins
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Chen-Ming Chang
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Applied Physics, Stanford University, Stanford, California, USA
| | - Craig S Levin
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA.,Department of Physics, Stanford University, Stanford, California, USA
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26
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Schindler TH. Cardiovascular PET/MR imaging: Quo Vadis? J Nucl Cardiol 2017; 24:1007-1018. [PMID: 27659454 DOI: 10.1007/s12350-016-0451-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 02/08/2016] [Indexed: 12/30/2022]
Abstract
With the recent advent of PET/MRI scanners, the combination of molecular imaging with a variety of known and novel PET radiotracers, the high spatial resolution of MRI, and its potential for multi-parametric imaging are anticipated to increase the diagnostic accuracy in cardiovascular disease detection, while providing novel mechanistic insights into the initiation and progression of the disease state. For the time being, cardiac PET/MRI emerges as potential clinical tool in the identification and characterization of infiltrative cardiac diseases, such as sarcoidosis, acute or chronic myocarditis, and cardiac tumors, respectively. The application of PET/MRI in conjunction with various radiotracer probes in the identification of the vulnerable atherosclerotic plaque also holds much promise but needs further translation and validation in clinical investigations. The combination of molecular imaging and creation of multi-parametric imaging maps with PET/MRI, however, are likely to set new horizons to develop predictive parameters for myocardial recovery and treatment response in ischemic and non-ischemic cardiomyopathy patients. Molecular imaging and multi-parametric imaging in cardiovascular disease with PET/MRI at current stage are at its infancy but bear a bright future.
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Affiliation(s)
- Thomas Hellmut Schindler
- Department of Radiology and Radiological Science, Division of Nuclear Medicine, Nuclear Cardiovascular Medicine, Johns Hopkins University School of Medicine, 3225, 601 N. Caroline Street, Baltimore, MD, 21287, USA.
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27
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Schindler TH. Cardiovascular PET/MR: "Not the end but the beginning". J Nucl Cardiol 2017; 24:1098-1100. [PMID: 28127686 DOI: 10.1007/s12350-017-0784-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 10/20/2022]
Affiliation(s)
- Thomas Hellmut Schindler
- Division of Nuclear Medicine, Cardiovascular Nuclear Medicine, Department of Radiology and Radiological Science SOM, JHOC, Johns Hopkins University School of Medicine, 3225, 601 N. Caroline Street, Baltimore, MD, 21287, USA.
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Bailey DL, Eslick EM, Schembri GP, Roach PJ. (68)Ga PET Ventilation and Perfusion Lung Imaging-Current Status and Future Challenges. Semin Nucl Med 2017; 46:428-35. [PMID: 27553468 DOI: 10.1053/j.semnuclmed.2016.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gallium-68 ((68)Ga) is a positron-emitting radionuclide suitable for positron emission tomography (PET) imaging that has a number of convenient features-it has a physical half life of 68 minutes, it is generator produced at the PET facility and needs no local cyclotron, and being a radiometal is able to be chelated to a number of useful molecules for diagnostic imaging with PET. (68)Ga has recently been investigated as a radiotracer for ventilation and perfusion (V/Q) lung imaging. It is relatively easy to produce both V/Q radiopharmaceuticals labeled with (68)Ga for PET studies, it offers higher spatial resolution than equivalent SPECT studies, the short half life allows for multiple (repeated) scans on the same day, and low amounts of radiotracer can be used thus limiting the radiation dose to the subject. In the usual clinical setting requiring a V/Q scan, that of suspected pulmonary embolism, the role of (68)Ga V/Q PET may be limited from a logistical perspective, however, in nonacute applications such as lung function evaluation, radiotherapy treatment planning, and respiratory physiology investigations it would appear to be an ideal modality to employ.
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Affiliation(s)
- Dale L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia; Faculty of Health Sciences, University of Sydney, Sydney, Australia.
| | - Enid M Eslick
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Geoffrey P Schembri
- Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia; Sydney Medical School, University of Sydney, Sydney, Australia
| | - Paul J Roach
- Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia; Sydney Medical School, University of Sydney, Sydney, Australia
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29
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Lindenberg L, Ahlman M, Turkbey B, Mena E, Choyke P. Evaluation of Prostate Cancer with PET/MRI. J Nucl Med 2017; 57:111S-116S. [PMID: 27694163 DOI: 10.2967/jnumed.115.169763] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/24/2016] [Indexed: 12/22/2022] Open
Abstract
In the ongoing effort to understand and cure prostate cancer, imaging modalities are constantly evolving to assist in clinical decisions. Multiparametric MRI can be used to direct prostate biopsies, improve diagnostic yield, and help clinicians make more accurate decisions. PET is superior in providing biologic information about the cancer and is sensitive and highly specific. Integrated PET/MRI is a welcome technical advance with great potential to influence the diagnosis and management of prostate cancer in clinical practice.
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Affiliation(s)
- Liza Lindenberg
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Mark Ahlman
- Department of Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland; and
| | - Baris Turkbey
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Esther Mena
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Peter Choyke
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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30
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Oehmigen M, Lindemann ME, Lanz T, Kinner S, Quick HH. Integrated PET/MR breast cancer imaging: Attenuation correction and implementation of a 16-channel RF coil. Med Phys 2017; 43:4808. [PMID: 27487899 DOI: 10.1118/1.4959546] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE This study aims to develop, implement, and evaluate a 16-channel radiofrequency (RF) coil for integrated positron emission tomography/magnetic resonance (PET/MR) imaging of breast cancer. The RF coil is designed for optimized MR imaging performance and PET transparency and attenuation correction (AC) is applied for accurate PET quantification. METHODS A 16-channel breast array RF coil was designed for integrated PET/MR hybrid imaging of breast cancer lesions. The RF coil features a lightweight rigid design and is positioned with a spacer at a defined position on the patient table of an integrated PET/MR system. Attenuation correction is performed by generating and applying a dedicated 3D CT-based template attenuation map. Reposition accuracy of the RF coil on the system patient table while using the positioning frame was tested in repeated measurements using MR-visible markers. The MR, PET, and PET/MR imaging performances were systematically evaluated using modular breast phantoms. Attenuation correction of the RF coil was evaluated with difference measurements of the active breast phantoms filled with radiotracer in the PET detector with and without the RF coil in place, serving as a standard of reference measurement. The overall PET/MR imaging performance and PET quantification accuracy of the new 16-channel RF coil and its AC were then evaluated in first clinical examinations on ten patients with local breast cancer. RESULTS The RF breast array coil provides excellent signal-to-noise ratio and signal homogeneity across the volume of the breast phantoms in MR imaging and visualizes small structures in the phantoms down to 0.4 mm in plane. Difference measurements with PET revealed a global loss and thus attenuation of counts by 13% (mean value across the whole phantom volume) when the RF coil is placed in the PET detector. Local attenuation ranging from 0% in the middle of the phantoms up to 24% was detected in the peripheral regions of the phantoms at positions closer to attenuating hardware structures of the RF coil. The position accuracy of the RF coil on the patient table when using the positioning frame was determined well below 1 mm for all three spatial dimensions. This ensures perfect position match between the RF coil and its three-dimensional attenuation template during the PET data reconstruction process. When applying the CT-based AC of the RF coil, the global attenuation bias was mostly compensated to ±0.5% across the entire breast imaging volume. The patient study revealed high quality MR, PET, and combined PET/MR imaging of breast cancer. Quantitative activity measurements in all 11 breast cancer lesions of the ten patients resulted in increased mean difference values of SUVmax 11.8% (minimum 3.2%; maximum 23.2%) between nonAC images and images when AC of the RF breast coil was applied. This supports the quantitative results of the phantom study as well as successful attenuation correction of the RF coil. CONCLUSIONS A 16-channel breast RF coil was designed for optimized MR imaging performance and PET transparency and was successfully integrated with its dedicated attenuation correction template into a whole-body PET/MR system. Systematic PET/MR imaging evaluation with phantoms and an initial study on patients with breast cancer provided excellent MR and PET image quality and accurate PET quantification.
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Affiliation(s)
- Mark Oehmigen
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen 45147, Germany
| | - Maike E Lindemann
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen 45147, Germany
| | - Titus Lanz
- Rapid Biomedical GmbH, Rimpar 97222, Germany
| | - Sonja Kinner
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen 45147, Germany
| | - Harald H Quick
- High Field and Hybrid MR Imaging, University Hospital Essen, Essen 45147, Germany and Erwin L. Hahn Institute for MR Imaging, University Duisburg-Essen, Essen 45141, Germany
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Rausch I, Rischka L, Ladefoged CN, Furtner J, Fenchel M, Hahn A, Lanzenberger R, Mayerhoefer ME, Traub-Weidinger T, Beyer T. PET/MRI for Oncologic Brain Imaging: A Comparison of Standard MR-Based Attenuation Corrections with a Model-Based Approach for the Siemens mMR PET/MR System. J Nucl Med 2017; 58:1519-1525. [DOI: 10.2967/jnumed.116.186148] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/31/2017] [Indexed: 11/16/2022] Open
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Abstract
This article summarizes recent advances in PET/MR imaging in gynecologic cancers and the emerging clinical value of PET/MR imaging in the management of the 3 most common gynecologic malignancies: cervical, endometrial, and ovarian cancers. PET/MR imaging offers superior soft tissue contrast, improved assessment of primary tumor involvement because of high-resolution multiplanar reformats, and functional MR techniques such as diffusion-weighted MR imaging and dynamic contrast-enhanced MR imaging. This article discusses the challenges, future directions, and technical advances of PET/MR imaging, and the emerging new multimodality, multiparametric imaging techniques for integrating morphologic, functional, and molecular imaging data.
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Schober O, Dössel O, Ermert H, Requardt H, Ziegler S, Adam G. [Imaging in clinic and research: contribution to individualized medicine?]. Nuklearmedizin 2017. [PMID: 29533421 DOI: 10.3413/2017-05-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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34
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Ladefoged CN, Law I, Anazodo U, St Lawrence K, Izquierdo-Garcia D, Catana C, Burgos N, Cardoso MJ, Ourselin S, Hutton B, Mérida I, Costes N, Hammers A, Benoit D, Holm S, Juttukonda M, An H, Cabello J, Lukas M, Nekolla S, Ziegler S, Fenchel M, Jakoby B, Casey ME, Benzinger T, Højgaard L, Hansen AE, Andersen FL. A multi-centre evaluation of eleven clinically feasible brain PET/MRI attenuation correction techniques using a large cohort of patients. Neuroimage 2016; 147:346-359. [PMID: 27988322 PMCID: PMC6818242 DOI: 10.1016/j.neuroimage.2016.12.010] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/14/2016] [Accepted: 12/05/2016] [Indexed: 01/27/2023] Open
Abstract
AIM To accurately quantify the radioactivity concentration measured by PET, emission data need to be corrected for photon attenuation; however, the MRI signal cannot easily be converted into attenuation values, making attenuation correction (AC) in PET/MRI challenging. In order to further improve the current vendor-implemented MR-AC methods for absolute quantification, a number of prototype methods have been proposed in the literature. These can be categorized into three types: template/atlas-based, segmentation-based, and reconstruction-based. These proposed methods in general demonstrated improvements compared to vendor-implemented AC, and many studies report deviations in PET uptake after AC of only a few percent from a gold standard CT-AC. Using a unified quantitative evaluation with identical metrics, subject cohort, and common CT-based reference, the aims of this study were to evaluate a selection of novel methods proposed in the literature, and identify the ones suitable for clinical use. METHODS In total, 11 AC methods were evaluated: two vendor-implemented (MR-ACDIXON and MR-ACUTE), five based on template/atlas information (MR-ACSEGBONE (Koesters et al., 2016), MR-ACONTARIO (Anazodo et al., 2014), MR-ACBOSTON (Izquierdo-Garcia et al., 2014), MR-ACUCL (Burgos et al., 2014), and MR-ACMAXPROB (Merida et al., 2015)), one based on simultaneous reconstruction of attenuation and emission (MR-ACMLAA (Benoit et al., 2015)), and three based on image-segmentation (MR-ACMUNICH (Cabello et al., 2015), MR-ACCAR-RiDR (Juttukonda et al., 2015), and MR-ACRESOLUTE (Ladefoged et al., 2015)). We selected 359 subjects who were scanned using one of the following radiotracers: [18F]FDG (210), [11C]PiB (51), and [18F]florbetapir (98). The comparison to AC with a gold standard CT was performed both globally and regionally, with a special focus on robustness and outlier analysis. RESULTS The average performance in PET tracer uptake was within ±5% of CT for all of the proposed methods, with the average±SD global percentage bias in PET FDG uptake for each method being: MR-ACDIXON (-11.3±3.5)%, MR-ACUTE (-5.7±2.0)%, MR-ACONTARIO (-4.3±3.6)%, MR-ACMUNICH (3.7±2.1)%, MR-ACMLAA (-1.9±2.6)%, MR-ACSEGBONE (-1.7±3.6)%, MR-ACUCL (0.8±1.2)%, MR-ACCAR-RiDR (-0.4±1.9)%, MR-ACMAXPROB (-0.4±1.6)%, MR-ACBOSTON (-0.3±1.8)%, and MR-ACRESOLUTE (0.3±1.7)%, ordered by average bias. The overall best performing methods (MR-ACBOSTON, MR-ACMAXPROB, MR-ACRESOLUTE and MR-ACUCL, ordered alphabetically) showed regional average errors within ±3% of PET with CT-AC in all regions of the brain with FDG, and the same four methods, as well as MR-ACCAR-RiDR, showed that for 95% of the patients, 95% of brain voxels had an uptake that deviated by less than 15% from the reference. Comparable performance was obtained with PiB and florbetapir. CONCLUSIONS All of the proposed novel methods have an average global performance within likely acceptable limits (±5% of CT-based reference), and the main difference among the methods was found in the robustness, outlier analysis, and clinical feasibility. Overall, the best performing methods were MR-ACBOSTON, MR-ACMAXPROB, MR-ACRESOLUTE and MR-ACUCL, ordered alphabetically. These methods all minimized the number of outliers, standard deviation, and average global and local error. The methods MR-ACMUNICH and MR-ACCAR-RiDR were both within acceptable quantitative limits, so these methods should be considered if processing time is a factor. The method MR-ACSEGBONE also demonstrates promising results, and performs well within the likely acceptable quantitative limits. For clinical routine scans where processing time can be a key factor, this vendor-provided solution currently outperforms most methods. With the performance of the methods presented here, it may be concluded that the challenge of improving the accuracy of MR-AC in adult brains with normal anatomy has been solved to a quantitatively acceptable degree, which is smaller than the quantification reproducibility in PET imaging.
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Affiliation(s)
- Claes N Ladefoged
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | | | | | - David Izquierdo-Garcia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Ciprian Catana
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Ninon Burgos
- Translational Imaging Group, Centre for Medical Image Computing, University College London, NW1 2HE, London, UK
| | - M Jorge Cardoso
- Translational Imaging Group, Centre for Medical Image Computing, University College London, NW1 2HE, London, UK; Dementia Research Centre, Institute of Neurology, University College London, WC1N 3AR, London, UK
| | - Sebastien Ourselin
- Translational Imaging Group, Centre for Medical Image Computing, University College London, NW1 2HE, London, UK; Dementia Research Centre, Institute of Neurology, University College London, WC1N 3AR, London, UK
| | - Brian Hutton
- Institute of Nuclear Medicine, University College London, London, UK
| | - Inés Mérida
- LILI-EQUIPEX - Lyon Integrated Life Imaging: hybrid MR-PET, CERMEP Imaging Centre, Lyon, France; Siemens Healthcare France SAS, Saint-Denis, France
| | - Nicolas Costes
- LILI-EQUIPEX - Lyon Integrated Life Imaging: hybrid MR-PET, CERMEP Imaging Centre, Lyon, France
| | - Alexander Hammers
- LILI-EQUIPEX - Lyon Integrated Life Imaging: hybrid MR-PET, CERMEP Imaging Centre, Lyon, France; King's College London & Guy's and St Thomas' PET Centre, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | - Didier Benoit
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | - Søren Holm
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | - Meher Juttukonda
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Hongyu An
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Jorge Cabello
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany
| | - Mathias Lukas
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany
| | - Stephan Nekolla
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany
| | - Sibylle Ziegler
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany
| | | | - Bjoern Jakoby
- Siemens Healthcare GmbH, Erlangen, Germany; University of Surrey, Guildford, Surrey, UK
| | | | - Tammie Benzinger
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63130, USA
| | - Liselotte Højgaard
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | - Adam E Hansen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark
| | - Flemming L Andersen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Copenhagen, Denmark.
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Gillies RJ, Beyer T. PET and MRI: Is the Whole Greater than the Sum of Its Parts? Cancer Res 2016; 76:6163-6166. [PMID: 27729326 DOI: 10.1158/0008-5472.can-16-2121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/19/2016] [Indexed: 01/22/2023]
Abstract
Over the past decades, imaging in oncology has been undergoing a "quiet" revolution to treat images as data, not as pictures. This revolution has been sparked by technological advances that enable capture of images that reflect not only anatomy, but also of tissue metabolism and physiology in situ Important advances along this path have been the increasing power of MRI, which can be used to measure spatially dependent differences in cell density, tissue organization, perfusion, and metabolism. In parallel, PET imaging allows quantitative assessment of the spatial localization of positron-emitting compounds, and it has also been constantly improving in the number of imageable tracers to measure metabolism and expression of macromolecules. Recent years have witnessed another technological advance, wherein these two powerful modalities have been physically merged into combined PET/MRI systems, appropriate for both preclinical or clinical imaging. As with all new enabling technologies driven by engineering physics, the full extent of potential applications is rarely known at the outset. In the work of Schmitz and colleagues, the authors have combined multiparametric MRI and PET imaging to address the important issue of intratumoral heterogeneity in breast cancer using both preclinical and clinical data. With combined PET and MRI and sophisticated machine-learning tools, they have been able identify multiple coexisting regions ("habitats") within living tumors and, in some cases, have been able to assign these habitats to known histologies. This work addresses an issue of fundamental importance to both cancer biology and cancer care. As with most new paradigm-shifting applications, it is not the last word on the subject and introduces a number of new avenues of investigation to pursue. Cancer Res; 76(21); 6163-6. ©2016 AACR.
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Affiliation(s)
- Robert J Gillies
- Department of Radiology, H Lee Moffitt Cancer Center and Research Institute, Tampa, Florida. .,Department of Cancer Imaging, H Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Thomas Beyer
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, General Hospital Vienna, Vienna, Austria
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Wall MB, Birch D, Yong MY. Opportunities and considerations for visualising neuroimaging data on very large displays. F1000Res 2016; 5:2157. [PMID: 27703670 PMCID: PMC5031127 DOI: 10.12688/f1000research.9522.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/30/2016] [Indexed: 11/20/2022] Open
Abstract
Neuroimaging experiments can generate impressive volumes of data and many images of the results. This is particularly true of multi-modal imaging studies that use more than one imaging technique, or when imaging is combined with other assessments. A challenge for these studies is appropriate visualisation of results in order to drive insights and guide accurate interpretations. Next-generation visualisation technology therefore has much to offer the neuroimaging community. One example is the Imperial College London Data Observatory; a high-resolution (132 megapixel) arrangement of 64 monitors, arranged in a 313 degree arc, with a 6 metre diameter, powered by 32 rendering nodes. This system has the potential for high-resolution, large-scale display of disparate data types in a space designed to promote collaborative discussion by multiple researchers and/or clinicians. Opportunities for the use of the Data Observatory are discussed, with particular reference to applications in Multiple Sclerosis (MS) research and clinical practice. Technical issues and current work designed to optimise the use of the Data Observatory for neuroimaging are also discussed, as well as possible future research that could be enabled by the use of the system in combination with eye-tracking technology.
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Affiliation(s)
- Matthew B Wall
- Imanova Centre for Imaging Sciences, London, W12 0NN, UK; Division of Brain Sciences, Imperial College London, London, SW7 2AZ, UK; Clinical Psychopharmacology Unit, University College London, London, WC1E 7HB, UK
| | - David Birch
- Data Science Institute, Imperial College London, London, SW7 2AZ, UK
| | - May Y Yong
- Data Science Institute, Imperial College London, London, SW7 2AZ, UK
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Progress of Multimodal Molecular Imaging Technology in Diagnosis of Tumor. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2016. [DOI: 10.1016/s1872-2040(16)60966-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Bailey DL, Pichler BJ, Gückel B, Barthel H, Beer AJ, Botnar R, Gillies R, Goh V, Gotthardt M, Hicks RJ, Lanzenberger R, la Fougere C, Lentschig M, Nekolla SG, Niederdraenk T, Nikolaou K, Nuyts J, Olego D, Riklund KÅ, Signore A, Schäfers M, Sossi V, Suminski M, Veit-Haibach P, Umutlu L, Wissmeyer M, Beyer T. Combined PET/MRI: from Status Quo to Status Go. Summary Report of the Fifth International Workshop on PET/MR Imaging; February 15-19, 2016; Tübingen, Germany. Mol Imaging Biol 2016; 18:637-50. [PMID: 27534971 PMCID: PMC5010606 DOI: 10.1007/s11307-016-0993-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article provides a collaborative perspective of the discussions and conclusions from the fifth international workshop of combined positron emission tomorgraphy (PET)/magnetic resonance imaging (MRI) that was held in Tübingen, Germany, from February 15 to 19, 2016. Specifically, we summarise the second part of the workshop made up of invited presentations from active researchers in the field of PET/MRI and associated fields augmented by round table discussions and dialogue boards with specific topics. This year, this included practical advice as to possible approaches to moving PET/MRI into clinical routine, the use of PET/MRI in brain receptor imaging, in assessing cardiovascular diseases, cancer, infection, and inflammatory diseases. To address perceived challenges still remaining to innovatively integrate PET and MRI system technologies, a dedicated round table session brought together key representatives from industry and academia who were engaged with either the conceptualisation or early adoption of hybrid PET/MRI systems. Discussions during the workshop highlighted that emerging unique applications of PET/MRI such as the ability to provide multi-parametric quantitative and visual information which will enable not only overall disease detection but also disease characterisation would eventually be regarded as compelling arguments for the adoption of PET/MR. However, as indicated by previous workshops, evidence in favour of this observation is only growing slowly, mainly due to the ongoing inability to pool data cohorts from independent trials as well as different systems and sites. The participants emphasised that moving from status quo to status go entails the need to adopt standardised imaging procedures and the readiness to act together prospectively across multiple PET/MRI sites and vendors.
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Affiliation(s)
- D L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, and Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - B J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard-Karls-Universität, Tübingen, Germany
| | - B Gückel
- Department of Interventional and Diagnostic Radiology, Eberhard-Karls-Universität, Tübingen, Germany
| | - H Barthel
- Department of Nuclear Medicine, University Clinic, Leipzig, Germany
| | - A J Beer
- Department of Nuclear Medicine, Ulm University, Ulm, Germany
| | - R Botnar
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | | | - V Goh
- Division of Imaging Sciences and Biomedical Engineering, Department of Cancer Imaging, King's College London, London, UK
| | - M Gotthardt
- Department of Nuclear Medicine, Radboud University, Nijmegen, The Netherlands
| | - R J Hicks
- Peter MacCallum Cancer Centre, Melbourne, Australia
| | - R Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - C la Fougere
- Division of Nuclear Medicine and clinical Molecular Imaging, Department of Radiology, University of Tübingen, Tübingen, Germany
| | - M Lentschig
- ZEMODI, Zentrum für Moderne Diagnostik, Bremen, Germany
| | - S G Nekolla
- Department of Nuclear Medicine, Technical University Munich, Munich, Germany
| | - T Niederdraenk
- Strategy and Innovation Technology Center, Siemens Healthcare GmbH, Erlangen, Germany
| | - K Nikolaou
- Department of Interventional and Diagnostic Radiology, Eberhard-Karls-Universität, Tübingen, Germany
| | - J Nuyts
- Department of Imaging and Pathology, Nuclear Medicine and Molecular Imaging, KU Leuven - University of Leuven, Leuven, Belgium
| | - D Olego
- Philips, 3000 Minuteman Road, Andover, MA, 01810, USA
| | - K Åhlström Riklund
- Department of Diagnostic Radiology, Radiation Sciences, Umeå University/Norrlands University Hospital, Umeå, Sweden
| | - A Signore
- Nuclear Medicine Unit, Departments of Medical-Surgical Sciences and Translational Medicine, "Sapienza" University of Rome, Rome, Italy
| | - M Schäfers
- Department of Nuclear Medicine, University Hospital Münster and European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - V Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | | | - P Veit-Haibach
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - L Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - M Wissmeyer
- Department of Nuclear Medicine, University Hospital of Geneva, Geneva, Switzerland
| | - T Beyer
- Center for Medical Physics and Biomedical Engineering, General Hospital Vienna, Medical University Vienna, 4L, Waehringer Guertel 18-20, 1090, Vienna, Austria.
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Diken M, Pektor S, Miederer M. Harnessing the potential of noninvasive in vivo preclinical imaging of the immune system: challenges and prospects. Nanomedicine (Lond) 2016; 11:2711-2722. [PMID: 27628499 DOI: 10.2217/nnm-2016-0187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Preclinical imaging has become a powerful method for investigation of in vivo processes such as pharmacokinetics of therapeutic substances and visualization of physiologic and pathophysiological mechanisms. These are important aspects to understand diseases and develop strategies to modify their progression with pharmacologic interventions. One promising intervention is the application of specifically tailored nanoscale particles that modulate the immune system to generate a tumor targeting immune response. In this complex interaction between immunomodulatory therapies, the immune system and malignant disease, imaging methods are expected to play a key role on the way to generate new therapeutic strategies. Here, we summarize examples which demonstrate the current potential of imaging methods and develop a perspective on the future value of preclinical imaging of the immune system.
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Affiliation(s)
- Mustafa Diken
- TRON - Translational Oncology at the University Medical Center of Johannes Gutenberg University gGmbH, Mainz, Germany
| | - Stefanie Pektor
- Department of Nuclear Medicine, University Medical Center Mainz, Mainz, Germany
| | - Matthias Miederer
- Department of Nuclear Medicine, University Medical Center Mainz, Mainz, Germany
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Lindenberg L, Ahlman M, Turkbey B, Mena E, Choyke P. Advancement of MR and PET/MR in Prostate Cancer. Semin Nucl Med 2016; 46:536-543. [PMID: 27825433 DOI: 10.1053/j.semnuclmed.2016.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Multiparametric magnetic resonance (mpMRI) imaging has assumed a larger role in the diagnosis and management of prostate cancer. The current method of detecting prostate cancer relies on blind systematic biopsy, guided only by transrectal ultrasound that generally directs the needle biopsy to sextants of the prostate rather than specific lesions. MpMRI is playing an increasing role in the detection of primary cancer as it can visualize cancers and direct biopsies. However, even mpMRI is inherently nonspecific and numerous biopsies performed under MR guidance prove to be negative. Positron emission tomography (PET) has the potential to improve the sensitivity and specificity for prostate cancer in combination with mpMRI. Prostate-specific membrane antigen is a widely expressed tumor antigen in prostate cancer for which multiple PET ligands, labeled with 68Ga and 18F, are being developed. However, the low spatial resolution of PET mandates that it be combined with a higher resolution imaging modality, which typically has been computed tomography (CT). However, MRI is not only better at localizing lesions in the prostate and prostatic bed, but it is also more sensitive than CT for early bone marrow changes in bone metastases caused by prostate cancer. Prostate-specific membrane antigen-based PET agents show promise in the early detection of recurrent and metastatic disease. Recent developments in hybrid imaging now allow PET/MRI to be performed simultaneously on a single scanner allowing one-to-one correspondence between the PET activity and MRI findings. This offers the opportunity for both high sensitivity and specificity with excellent anatomic location and could allow for more targeted biopsies and treatments. Here, we review the current status of PET/MRI for prostate cancer.
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Affiliation(s)
- Liza Lindenberg
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Mark Ahlman
- Department of Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD
| | - Baris Turkbey
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Esther Mena
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Peter Choyke
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD.
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Fendler WP, Czernin J, Herrmann K, Beyer T. Variations in PET/MRI Operations: Results from an International Survey Among 39 Active Sites. J Nucl Med 2016; 57:2016-2021. [PMID: 27516448 DOI: 10.2967/jnumed.116.174169] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/30/2016] [Indexed: 11/16/2022] Open
Abstract
Information has been collected from PET/MRI operational sites to identify its present and future applications. This may help to focus discussions on common interests of the PET/MRI community. METHODS A web-based survey of PET/MRI users was conducted from June to October 2015. The survey was composed of 26 questions related to the PET/MRI center, present use and imaging protocols, and perspectives on key applications. RESULTS Responses were collected from 39 international sites that operated PET/MRI for a median of 30 mo (range, 2-62 mo). Most installations were located in public institutions with an academic focus (n = 26, 67%). Systems were primarily operated by nuclear medicine departments (n = 13, 33%), jointly by nuclear medicine and radiology (n = 11, 28%), and radiology only (n = 10, 26%). PET/MRI operation was equally focused on clinic routine and research (47% vs. 45% of sites, respectively). Sites reported a strong focus on oncology (76% of research and 88% of clinical applications). Other applications included neurology (9% clinical, 12% research) and cardiology (3% clinical, 6% research). Perceived superiority over PET/CT was identified as the strongest driver for clinical adoption. Over half the operators expect PET/MRI to excel in clinical routine within 3-5 y. Emerging key applications for future PET/MRI use were cardiovascular disease and imaging of inflammation. CONCLUSION An international survey of early PET/MR adopters reveals a mixed use of this combined imaging modality, with a focus on oncology. The future of PET/MRI is seen in expanded application for oncology and neurology, but also cardiovascular disease and inflammation.
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Affiliation(s)
- Wolfgang Peter Fendler
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Johannes Czernin
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Ken Herrmann
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Thomas Beyer
- Centre of Medical Physics and Biomedical Engineering, QIMP, Medical University of Vienna, Vienna, Austria
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Ripa RS, Pedersen SF, Kjær A. PET/MR Imaging in Vascular Disease: Atherosclerosis and Inflammation. PET Clin 2016; 11:479-88. [PMID: 27593251 DOI: 10.1016/j.cpet.2016.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
For imaging of atherosclerotic disease, lumenography using computed tomography, ultrasonography, or invasive angiography is still the backbone of evaluation. However, these methods are less effective to predict the likelihood of future thromboembolic events caused by vulnerability of plaques. PET and MR imaging have been used separately with success for plaque characterization. Where MR imaging has the ability to reveal plaque composition, PET has the ability to visualize plaque activity. Together this leads to a comprehensive evaluation of plaque vulnerability. In this review, the authors go through data and arguments that support increased use of PET/MR imaging in atherosclerotic imaging.
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Affiliation(s)
- Rasmus Sejersten Ripa
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, KF-4012, Rigshosptialet, Blegdamsvej 9, Copenhagen 2100, Denmark
| | - Sune Folke Pedersen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, KF-4012, Rigshosptialet, Blegdamsvej 9, Copenhagen 2100, Denmark
| | - Andreas Kjær
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, KF-4012, Rigshosptialet, Blegdamsvej 9, Copenhagen 2100, Denmark.
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Reimold M, la Fougère C. Molekulare Bildgebung bei neurologischen Erkrankungen. Radiologe 2016; 56:580-7. [DOI: 10.1007/s00117-016-0124-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Werner P, Rullmann M, Bresch A, Tiepolt S, Jochimsen T, Lobsien D, Schroeter ML, Sabri O, Barthel H. Impact of attenuation correction on clinical [(18)F]FDG brain PET in combined PET/MRI. EJNMMI Res 2016; 6:47. [PMID: 27255510 PMCID: PMC4891306 DOI: 10.1186/s13550-016-0200-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/23/2016] [Indexed: 01/03/2023] Open
Abstract
Background In PET/MRI, linear photon attenuation coefficients for attenuation correction (AC) cannot be directly derived, and cortical bone is, so far, usually not considered. This results in an underestimation of the average PET signal in PET/MRI. Recently introduced MR-AC methods predicting bone information from anatomic MRI or proton density-weighted zero-time imaging may solve this problem in the future. However, there is an ongoing debate if the current error is acceptable for clinical use and/or research. Methods We examined this feature for [18F] fluorodeoxyglucose (FDG) brain PET in 13 patients with clinical signs of dementia or movement disorders who subsequently underwent PET/CT and PET/MRI on the same day. Multiple MR-AC approaches including a CT-derived AC were applied. Results The resulting PET data was compared to the CT-derived standard regarding the quantification error and its clinical impact. On a quantitative level, −11.9 to +2 % deviations from the CT-AC standard were found. These deviations, however, did not translate into a systematic diagnostic error. This, as overall patterns of hypometabolism (which are decisive for clinical diagnostics), remained largely unchanged. Conclusions Despite a quantitative error by the omission of bone in MR-AC, clinical quality of brain [18F]FDG is not relevantly affected. Thus, brain [18F]FDG PET can already, even now with suboptimal MR-AC, be utilized for clinical routine purposes, even though the MR-AC warrants improvement.
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Affiliation(s)
- P Werner
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - M Rullmann
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - A Bresch
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - S Tiepolt
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - T Jochimsen
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - D Lobsien
- Department of Neuroradiology, Leipzig University Hospital, Leipzig, Germany
| | - M L Schroeter
- Day Clinic for Cognitive Neurology, Leipzig University Hospital and Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - O Sabri
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany
| | - H Barthel
- Department of Nuclear Medicine, Leipzig University Hospital, Leipzig, Germany.
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Preclinical models of atherosclerosis. The future of Hybrid PET/MR technology for the early detection of vulnerable plaque. Expert Rev Mol Med 2016; 18:e6. [PMID: 27056676 DOI: 10.1017/erm.2016.5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cardiovascular diseases are the leading cause of death in developed countries. The aetiology is currently multifactorial, thus making them very difficult to prevent. Preclinical models of atherothrombotic diseases, including vulnerable plaque-associated complications, are now providing significant insights into pathologies like atherosclerosis, and in combination with the most recent advances in new non-invasive imaging technologies, they have become essential tools to evaluate new therapeutic strategies, with which can forecast and prevent plaque rupture. Positron emission tomography (PET)/computed tomography imaging is currently used for plaque visualisation in clinical and pre-clinical cardiovascular research, albeit with significant limitations. However, the combination of PET and magnetic resonance imaging (MRI) technologies is still the best option available today, as combined PET/MRI scans provide simultaneous data acquisition together with high quality anatomical information, sensitivity and lower radiation exposure for the patient. The coming years may represent a new era for the implementation of PET/MRI in clinical practice, but first, clinically efficient attenuation correction algorithms and research towards multimodal reagents and safety issues should be validated at the preclinical level.
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PET/MRI and PET/CT: is there room for both at the top of the food chain? Eur J Nucl Med Mol Imaging 2015; 43:209-211. [DOI: 10.1007/s00259-015-3246-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 01/06/2023]
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