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Rausch I, Rust P, DiFranco MD, Lassen M, Stadlbauer A, Mayerhoefer ME, Hartenbach M, Hacker M, Beyer T. Reproducibility of MRI Dixon-Based Attenuation Correction in Combined PET/MR with Applications for Lean Body Mass Estimation. J Nucl Med 2016; 57:1096-101. [DOI: 10.2967/jnumed.115.168294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/08/2016] [Indexed: 01/09/2023] Open
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102
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Jang SH, Yi JH, Choi BY, Chang CH, Jung YJ, Lee HD, Yeo SS. Changes of the corticospinal tract in the unaffected hemisphere in stroke patients: A diffusion tensor imaging study. Somatosens Mot Res 2016; 33:1-7. [PMID: 26891746 DOI: 10.3109/08990220.2016.1142435] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We investigated changes of the corticospinal tract (CST) in the unaffected hemisphere according to severity of the CST injury, using diffusion tensor imaging (DTI). According to the severity of the CST injury in the affected hemisphere, the stroke patients showed different aspects of fiber volume increment of the CST in the unaffected hemisphere; the fiber volume was increased in the early phase in patients with mild injury of CST and later phase in patients with severe injury of CST.
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Affiliation(s)
- Sung Ho Jang
- a Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Ji Hyun Yi
- b Department of Diagnostic Radiology, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Byung Yeon Choi
- c Department of Neurosurgery, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Chul Hoon Chang
- c Department of Neurosurgery, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Young Jin Jung
- c Department of Neurosurgery, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Han Do Lee
- a Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University , Taegu , Republic of Korea
| | - Sang Seok Yeo
- d Department of Physical Therapy, College of Health Sciences, Dankook University , Cheonan , Republic of Korea
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103
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Blackledge MD, Collins DJ, Koh DM, Leach MO. Rapid development of image analysis research tools: Bridging the gap between researcher and clinician with pyOsiriX. Comput Biol Med 2016; 69:203-12. [PMID: 26773941 PMCID: PMC4761020 DOI: 10.1016/j.compbiomed.2015.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/07/2015] [Accepted: 12/03/2015] [Indexed: 01/08/2023]
Abstract
We present pyOsiriX, a plugin built for the already popular dicom viewer OsiriX that provides users the ability to extend the functionality of OsiriX through simple Python scripts. This approach allows users to integrate the many cutting-edge scientific/image-processing libraries created for Python into a powerful DICOM visualisation package that is intuitive to use and already familiar to many clinical researchers. Using pyOsiriX we hope to bridge the apparent gap between basic imaging scientists and clinical practice in a research setting and thus accelerate the development of advanced clinical image processing. We provide arguments for the use of Python as a robust scripting language for incorporation into larger software solutions, outline the structure of pyOsiriX and how it may be used to extend the functionality of OsiriX, and we provide three case studies that exemplify its utility. For our first case study we use pyOsiriX to provide a tool for smooth histogram display of voxel values within a user-defined region of interest (ROI) in OsiriX. We used a kernel density estimation (KDE) method available in Python using the scikit-learn library, where the total number of lines of Python code required to generate this tool was 22. Our second example presents a scheme for segmentation of the skeleton from CT datasets. We have demonstrated that good segmentation can be achieved for two example CT studies by using a combination of Python libraries including scikit-learn, scikit-image, SimpleITK and matplotlib. Furthermore, this segmentation method was incorporated into an automatic analysis of quantitative PET-CT in a patient with bone metastases from primary prostate cancer. This enabled repeatable statistical evaluation of PET uptake values for each lesion, before and after treatment, providing estaimes maximum and median standardised uptake values (SUVmax and SUVmed respectively). Following treatment we observed a reduction in lesion volume, SUVmax and SUVmed for all lesions, in agreement with a reduction in concurrent measures of serum prostate-specific antigen (PSA).
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Affiliation(s)
- Matthew D Blackledge
- CR-UK Cancer Imaging Centre, Radiotherapy and Imaging Division, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom.
| | - David J Collins
- CR-UK Cancer Imaging Centre, Radiotherapy and Imaging Division, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Dow-Mu Koh
- CR-UK Cancer Imaging Centre, Radiotherapy and Imaging Division, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Martin O Leach
- CR-UK Cancer Imaging Centre, Radiotherapy and Imaging Division, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
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104
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PET/MRI of central nervous system: current status and future perspective. Eur Radiol 2016; 26:3534-41. [PMID: 26780640 DOI: 10.1007/s00330-015-4202-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/15/2015] [Accepted: 12/30/2015] [Indexed: 12/18/2022]
Abstract
UNLABELLED Imaging plays an increasingly important role in the early diagnosis, prognosis prediction and therapy response evaluation of central nervous system (CNS) diseases. The newly emerging hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) can perform "one-stop-shop" evaluation, including anatomic, functional, biochemical and metabolic information, even at the molecular level, for personalised diagnoses and treatments of CNS diseases. However, there are still several problems to be resolved, such as appropriate PET detectors, attenuation correction and so on. This review will introduce the basic physical principles of PET/MRI and its potential clinical applications in the CNS. We also provide the future perspectives for this field. KEY POINTS • PET/MRI can simultaneously provide anatomic, functional, biochemical and metabolic information. • PET/MRI has promising potential in various central nervous system diseases. • Research on the future implementation of PET/MRI is challenging and encouraging.
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105
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Added Value of Integrated Whole-Body PET/MRI for Evaluation of Colorectal Cancer: Comparison With Contrast-Enhanced MDCT. AJR Am J Roentgenol 2016; 206:W10-20. [DOI: 10.2214/ajr.14.13818] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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106
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Lohrke J, Frenzel T, Endrikat J, Alves FC, Grist TM, Law M, Lee JM, Leiner T, Li KC, Nikolaou K, Prince MR, Schild HH, Weinreb JC, Yoshikawa K, Pietsch H. 25 Years of Contrast-Enhanced MRI: Developments, Current Challenges and Future Perspectives. Adv Ther 2016; 33:1-28. [PMID: 26809251 PMCID: PMC4735235 DOI: 10.1007/s12325-015-0275-4] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Indexed: 12/17/2022]
Abstract
UNLABELLED In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist(®)), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives. FUNDING Bayer HealthCare.
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Affiliation(s)
- Jessica Lohrke
- MR and CT Contrast Media Research, Bayer HealthCare, Berlin, Germany
| | - Thomas Frenzel
- MR and CT Contrast Media Research, Bayer HealthCare, Berlin, Germany
| | - Jan Endrikat
- Global Medical Affairs Radiology, Bayer HealthCare, Berlin, Germany
- Saarland University Hospital, Homburg, Germany
| | | | - Thomas M Grist
- Radiology, Medical Physics and Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Meng Law
- Radiology and Neurological Surgery, University of South California, Keck School of Medicine, USC University Hospital, Los Angeles, CA, USA
| | - Jeong Min Lee
- College of Medicine, Seoul National University Hospital, Seoul, South Korea
| | - Tim Leiner
- Radiology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - Kun-Cheng Li
- Radiology, Xuan Wu Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Konstantin Nikolaou
- Radiology, Ludwig-Maximilians University, University Hospitals, Munich, Germany
| | - Martin R Prince
- Radiology, Weill Cornell Medical College, New York, NY, USA
- Columbia College of Physicians and Surgeons, New York, NY, USA
| | | | | | - Kohki Yoshikawa
- Graduate Division of Medical Health Sciences, Graduate School of Komazawa University, Tokyo, Japan
| | - Hubertus Pietsch
- MR and CT Contrast Media Research, Bayer HealthCare, Berlin, Germany.
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107
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Wong AW, Fite BZ, Liu Y, Kheirolomoom A, Seo JW, Watson KD, Mahakian LM, Tam SM, Zhang H, Foiret J, Borowsky AD, Ferrara KW. Ultrasound ablation enhances drug accumulation and survival in mammary carcinoma models. J Clin Invest 2015; 126:99-111. [PMID: 26595815 DOI: 10.1172/jci83312] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/09/2015] [Indexed: 01/08/2023] Open
Abstract
Magnetic resonance-guided focused ultrasound (MRgFUS) facilitates noninvasive image-guided conformal thermal therapy of cancer. Yet in many scenarios, the sensitive tissues surrounding the tumor constrain the margins of ablation; therefore, augmentation of MRgFUS with chemotherapy may be required to destroy remaining tumor. Here, we used 64Cu-PET-CT, MRI, autoradiography, and fluorescence imaging to track the kinetics of long-circulating liposomes in immunocompetent mammary carcinoma-bearing FVB/n and BALB/c mice. We observed a 5-fold and 50-fold enhancement of liposome and drug concentration, respectively, within MRgFUS thermal ablation-treated tumors along with dense accumulation within the surrounding tissue rim. Ultrasound-enhanced drug accumulation was rapid and durable and greatly increased total tumor drug exposure over time. In addition, we found that the small molecule gadoteridol accumulates around and within ablated tissue. We further demonstrated that dilated vasculature, loss of vascular integrity resulting in extravasation of blood cells, stromal inflammation, and loss of cell-cell adhesion and tissue architecture all contribute to the enhanced accumulation of the liposomes and small molecule probe. The locally enhanced liposome accumulation was preserved even after a multiweek protocol of doxorubicin-loaded liposomes and partial ablation. Finally, by supplementing ablation with concurrent liposomal drug therapy, a complete and durable response was obtained using protocols for which a sub-mm rim of tumor remained after ablation.
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108
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Weissler B, Gebhardt P, Dueppenbecker PM, Wehner J, Schug D, Lerche CW, Goldschmidt B, Salomon A, Verel I, Heijman E, Perkuhn M, Heberling D, Botnar RM, Kiessling F, Schulz V. A Digital Preclinical PET/MRI Insert and Initial Results. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:2258-2270. [PMID: 25935031 DOI: 10.1109/tmi.2015.2427993] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Combining Positron Emission Tomography (PET) with Magnetic Resonance Imaging (MRI) results in a promising hybrid molecular imaging modality as it unifies the high sensitivity of PET for molecular and cellular processes with the functional and anatomical information from MRI. Digital Silicon Photomultipliers (dSiPMs) are the digital evolution in scintillation light detector technology and promise high PET SNR. DSiPMs from Philips Digital Photon Counting (PDPC) were used to develop a preclinical PET/RF gantry with 1-mm scintillation crystal pitch as an insert for clinical MRI scanners. With three exchangeable RF coils, the hybrid field of view has a maximum size of 160 mm × 96.6 mm (transaxial × axial). 0.1 ppm volume-root-mean-square B 0-homogeneity is kept within a spherical diameter of 96 mm (automatic volume shimming). Depending on the coil, MRI SNR is decreased by 13% or 5% by the PET system. PET count rates, energy resolution of 12.6% FWHM, and spatial resolution of 0.73 mm (3) (isometric volume resolution at isocenter) are not affected by applied MRI sequences. PET time resolution of 565 ps (FWHM) degraded by 6 ps during an EPI sequence. Timing-optimized settings yielded 260 ps time resolution. PET and MR images of a hot-rod phantom show no visible differences when the other modality was in operation and both resolve 0.8-mm rods. Versatility of the insert is shown by successfully combining multi-nuclei MRI ((1)H/(19)F) with simultaneously measured PET ((18)F-FDG). A longitudinal study of a tumor-bearing mouse verifies the operability, stability, and in vivo capabilities of the system. Cardiac- and respiratory-gated PET/MRI motion-capturing (CINE) images of the mouse heart demonstrate the advantage of simultaneous acquisition for temporal and spatial image registration.
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109
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Direct labeling of 19F-perfluorocarbon onto multilayered cell sheet for MRI-based non-invasive cell tracking. Tissue Eng Regen Med 2015. [DOI: 10.1007/s13770-014-0092-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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110
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Mehranian A, Zaidi H. Joint Estimation of Activity and Attenuation in Whole-Body TOF PET/MRI Using Constrained Gaussian Mixture Models. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:1808-1821. [PMID: 25769148 DOI: 10.1109/tmi.2015.2409157] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It has recently been shown that the attenuation map can be estimated from time-of-flight (TOF) PET emission data using joint maximum likelihood reconstruction of attenuation and activity (MLAA). In this work, we propose a novel MRI-guided MLAA algorithm for emission-based attenuation correction in whole-body PET/MR imaging. The algorithm imposes MR spatial and CT statistical constraints on the MLAA estimation of attenuation maps using a constrained Gaussian mixture model (GMM) and a Markov random field smoothness prior. Dixon water and fat MR images were segmented into outside air, lung, fat and soft-tissue classes and an MR low-intensity (unknown) class corresponding to air cavities, cortical bone and susceptibility artifacts. The attenuation coefficients over the unknown class were estimated using a mixture of four Gaussians, and those over the known tissue classes using unimodal Gaussians, parameterized over a patient population. To eliminate misclassification of spongy bones with surrounding tissues, and thus include them in the unknown class, we heuristically suppressed fat in water images and also used a co-registered bone probability map. The proposed MLAA-GMM algorithm was compared with the MLAA algorithms proposed by Rezaei and Salomon using simulation and clinical studies with two different tracer distributions. The results showed that our proposed algorithm outperforms its counterparts in suppressing the cross-talk and scaling problems of activity and attenuation and thus produces PET images of improved quantitative accuracy. It can be concluded that the proposed algorithm effectively exploits the MR information and can pave the way toward accurate emission-based attenuation correction in TOF PET/MRI.
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111
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Varoquaux A, Rager O, Dulguerov P, Burkhardt K, Ailianou A, Becker M. Diffusion-weighted and PET/MR Imaging after Radiation Therapy for Malignant Head and Neck Tumors. Radiographics 2015; 35:1502-27. [PMID: 26252192 DOI: 10.1148/rg.2015140029] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Interpreting imaging studies of the irradiated neck constitutes a challenge because of radiation therapy-induced tissue alterations, the variable appearances of recurrent tumors, and functional and metabolic phenomena that mimic disease. Therefore, morphologic magnetic resonance (MR) imaging, diffusion-weighted (DW) imaging, positron emission tomography with computed tomography (PET/CT), and software fusion of PET and MR imaging data sets are increasingly used to facilitate diagnosis in clinical practice. Because MR imaging and PET often yield complementary information, PET/MR imaging holds promise to facilitate differentiation of tumor recurrence from radiation therapy-induced changes and complications. This review focuses on clinical applications of DW and PET/MR imaging in the irradiated neck and discusses the added value of multiparametric imaging to solve diagnostic dilemmas. Radiologists should understand key features of radiation therapy-induced tissue alterations and potential complications seen at DW and PET/MR imaging, including edema, fibrosis, scar tissue, soft-tissue necrosis, bone and cartilage necrosis, cranial nerve palsy, and radiation therapy-induced arteriosclerosis, brain necrosis, and thyroid disorders. DW and PET/MR imaging also play a complementary role in detection of residual and recurrent disease. Interpretation pitfalls due to technical, functional, and metabolic phenomena should be recognized and avoided. Familiarity with DW and PET/MR imaging features of expected findings, potential complications, and treatment failure after radiation therapy increases diagnostic confidence when interpreting images of the irradiated neck. Online supplemental material is available for this article.
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Affiliation(s)
- Arthur Varoquaux
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
| | - Olivier Rager
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
| | - Pavel Dulguerov
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
| | - Karim Burkhardt
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
| | - Angeliki Ailianou
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
| | - Minerva Becker
- From the Department of Imaging, Divisions of Radiology (A.V., A.A., M.B.) and Nuclear Medicine (O.R.); Department of Clinical Neurosciences, Division of Otorhinolaryngology-Head and Neck Surgery (P.D.); and Department of Medical Genetics and Laboratory, Division of Clinical Pathology (K.B.); Geneva University Hospital, University of Geneva, Rue Gabrielle Perret Gentil 4, 1211 Geneva 14, Switzerland
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112
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Is Attenuation Correction for Myocardial Perfusion Imaging Underutilized? CURRENT CARDIOVASCULAR IMAGING REPORTS 2015. [DOI: 10.1007/s12410-015-9346-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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113
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Bashir U, Mallia A, Stirling J, Joemon J, MacKewn J, Charles-Edwards G, Goh V, Cook GJ. PET/MRI in Oncological Imaging: State of the Art. Diagnostics (Basel) 2015; 5:333-57. [PMID: 26854157 PMCID: PMC4665605 DOI: 10.3390/diagnostics5030333] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 02/08/2023] Open
Abstract
Positron emission tomography (PET) combined with magnetic resonance imaging (MRI) is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging.
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Affiliation(s)
- Usman Bashir
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
| | - Andrew Mallia
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
| | - James Stirling
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
- PET Imaging Centre and the Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
| | - John Joemon
- PET Imaging Centre and the Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
| | - Jane MacKewn
- PET Imaging Centre and the Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
| | - Geoff Charles-Edwards
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
- Medical Physics, Guy's & St Thomas' Hospitals NHS Foundation Trust, London, SE1 7EH, UK.
| | - Vicky Goh
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
- Department of Radiology, Guy's & St Thomas' Hospitals NHS Foundation Trust, London, SE1 7EH, UK.
| | - Gary J Cook
- Cancer Imaging Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
- PET Imaging Centre and the Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK.
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114
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Contemporary approaches for imaging skeletal metastasis. Bone Res 2015; 3:15024. [PMID: 26273541 PMCID: PMC4502405 DOI: 10.1038/boneres.2015.24] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 05/23/2015] [Indexed: 01/13/2023] Open
Abstract
The skeleton is a common site of cancer metastasis. Notably high incidences of bone lesions are found for breast, prostate, and renal carcinoma. Malignant bone tumors result in significant patient morbidity. Identification of these lesions is a critical step to accurately stratify patients, guide treatment course, monitor disease progression, and evaluate response to therapy. Diagnosis of cancer in the skeleton typically relies on indirect bone-targeted radiotracer uptake at sites of active bone remodeling. In this manuscript, we discuss established and emerging tools and techniques for detection of bone lesions, quantification of skeletal tumor burden, and current clinical challenges.
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115
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Ai H, Pan T. Feasibility of using respiration-averaged MR images for attenuation correction of cardiac PET/MR imaging. J Appl Clin Med Phys 2015. [PMID: 26218995 PMCID: PMC5690019 DOI: 10.1120/jacmp.v16i4.5194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac imaging is a promising application for combined PET/MR imaging. However, current MR imaging protocols for whole-body attenuation correction can produce spatial mismatch between PET and MR-derived attenuation data owing to a disparity between the two modalities' imaging speeds. We assessed the feasibility of using a respiration-averaged MR (AMR) method for attenuation correction of cardiac PET data in PET/MR images. First, to demonstrate the feasibility of motion imaging with MR, we used a 3T MR system and a two-dimensional fast spoiled gradient-recalled echo (SPGR) sequence to obtain AMR images ofa moving phantom. Then, we used the same sequence to obtain AMR images of a patient's thorax under free-breathing conditions. MR images were converted into PET attenuation maps using a three-class tissue segmentation method with two sets of predetermined CT numbers, one calculated from the patient-specific (PS) CT images and the other from a reference group (RG) containing 54 patient CT datasets. The MR-derived attenuation images were then used for attenuation correction of the cardiac PET data, which were compared to the PET data corrected with average CT (ACT) images. In the myocardium, the voxel-by-voxel differences and the differences in mean slice activity between the AMR-corrected PET data and the ACT-corrected PET data were found to be small (less than 7%). The use of AMR-derived attenuation images in place of ACT images for attenuation correction did not affect the summed stress score. These results demonstrate the feasibility of using the proposed SPGR-based MR imaging protocol to obtain patient AMR images and using those images for cardiac PET attenuation correction. Additional studies with more clinical data are warranted to further evaluate the method.
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Affiliation(s)
- Hua Ai
- The University of Texas MD Anderson Cancer Center.
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116
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Lee KH, Park CM, Lee SM, Lee JM, Cho JY, Paeng JC, Ahn SY, Goo JM. Pulmonary Nodule Detection in Patients with a Primary Malignancy Using Hybrid PET/MRI: Is There Value in Adding Contrast-Enhanced MR Imaging? PLoS One 2015; 10:e0129660. [PMID: 26065695 PMCID: PMC4465933 DOI: 10.1371/journal.pone.0129660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/11/2015] [Indexed: 01/04/2023] Open
Abstract
Purpose To investigate the added value of post-contrast VIBE (volumetric-interpolated breath-hold examination) to PET/MR imaging for pulmonary nodule detection in patients with primary malignancies. Materials and Methods This retrospective institutional review board–approved study, with waiver of informed consent, included 51 consecutive patients who underwent 18F-fluorodeoxyglucose (FDG) PET/MR followed by PET/CT for cancer staging. In all patients, the thorax was examined with pre-and post-contrast VIBE MR with simultaneous PET acquisition. Two readers blinded to the patients’ data independently recorded their level of suspicion for pulmonary nodules based on PET, pre-contrast VIBE, and fused PET/MR images (first session), and reassessed them 4-weeks later after addition of post-contrast VIBE (second session). Jackknife alternative free-response receiver-operating-characteristic (JAFROC) analysis was performed, with PET/CT as the reference standard. Results A total of 151 pulmonary nodules (44 FDG-avid, 107 non-FDG-avid nodules) were detected on PET/CT, including 62 nodules≥5mm in diameter and 89 nodules<5mm. In the first session, the average nodule detection rate was 53.3% for all nodules, 97.7% for FDG-avid, 35.0% for non-FDG-avid nodules, 87.9% for nodules≥5mm and 29.2% for nodules<5mm. In the second session, the average detection rate was 53.3% for all nodules, 97.7% for FDG-avid, 35.0% for non-FDG-avid nodules, 85.5% for nodules≥5mm and 30.9% for nodules<5mm. The average JAFROC figure-of-merit was 0.837 in the first session and 0.848 in the second session. There were no significant differences in detection performance between sessions (P=0.48). Conclusion The addition of post-contrast VIBE to hybrid PET/MR imaging provided no additional value in the detection of pulmonary nodules.
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Affiliation(s)
- Kyung Hee Lee
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Chang Min Park
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Department of Radiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
| | - Sang Min Lee
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Jeong Yeon Cho
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Jin Chul Paeng
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Su Yeon Ahn
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Jin Mo Goo
- Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
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Mehranian A, Zaidi H. Emission-based estimation of lung attenuation coefficients for attenuation correction in time-of-flight PET/MR. Phys Med Biol 2015; 60:4813-33. [PMID: 26047036 DOI: 10.1088/0031-9155/60/12/4813] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In standard segmentation-based MRI-guided attenuation correction (MRAC) of PET data on hybrid PET/MRI systems, the inter/intra-patient variability of linear attenuation coefficients (LACs) is ignored owing to the assignment of a constant LAC to each tissue class. This can lead to PET quantification errors, especially in the lung regions. In this work, we aim to derive continuous and patient-specific lung LACs from time-of-flight (TOF) PET emission data using the maximum likelihood reconstruction of activity and attenuation (MLAA) algorithm. The MLAA algorithm was constrained for estimation of lung LACs only in the standard 4-class MR attenuation map using Gaussian lung tissue preference and Markov random field smoothness priors. MRAC maps were derived from segmentation of CT images of 19 TOF-PET/CT clinical studies into background air, lung, soft tissue and fat tissue classes, followed by assignment of predefined LACs of 0, 0.0224, 0.0864 and 0.0975 cm(-1), respectively. The lung LACs of the resulting attenuation maps were then estimated from emission data using the proposed MLAA algorithm. PET quantification accuracy of MRAC and MLAA methods was evaluated against the reference CT-based AC method in the lungs, lesions located in/near the lungs and neighbouring tissues. The results show that the proposed MLAA algorithm is capable of retrieving lung density gradients and compensate fairly for respiratory-phase mismatch between PET and corresponding attenuation maps. It was found that the mean of the estimated lung LACs generally follow the trend of the reference CT-based attenuation correction (CTAC) method. Quantitative analysis revealed that the MRAC method resulted in average relative errors of -5.2 ± 7.1% and -6.1 ± 6.7% in the lungs and lesions, respectively. These were reduced by the MLAA algorithm to -0.8 ± 6.3% and -3.3 ± 4.7%, respectively. In conclusion, we demonstrated the potential and capability of emission-based methods in deriving patient-specific lung LACs to improve the accuracy of attenuation correction in TOF PET/MR imaging, thus paving the way for their adaptation in the clinic.
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Affiliation(s)
- Abolfazl Mehranian
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211, Geneva, Switzerland
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118
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Yoon SH, Goo JM, Lee SM, Park CM, Cheon GJ. PET/MR Imaging for Chest Diseases. Magn Reson Imaging Clin N Am 2015; 23:245-59. [DOI: 10.1016/j.mric.2015.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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119
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Mehranian A, Zaidi H. Clinical Assessment of Emission- and Segmentation-Based MR-Guided Attenuation Correction in Whole-Body Time-of-Flight PET/MR Imaging. J Nucl Med 2015; 56:877-83. [PMID: 25858043 DOI: 10.2967/jnumed.115.154807] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/23/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The joint maximum-likelihood reconstruction of activity and attenuation (MLAA) for emission-based attenuation correction has regained attention since the advent of time-of-flight PET/MR imaging. Recently, we improved the performance of the MLAA algorithm using an MR imaging-constrained gaussian mixture model (GMM). In this study, we compare the performance of our proposed algorithm with standard 4-class MR-based attenuation correction (MRAC) implemented on commercial systems. METHODS Five head and neck (18)F-FDG patients were scanned on PET/MR imaging and PET/CT scanners. Dixon fat and water MR images were registered to CT images. MRAC maps were derived by segmenting the MR images into 4 tissue classes and assigning predefined attenuation coefficients. For MLAA-GMM, MR images were segmented into known tissue classes, including fat, soft tissue, lung, background air, and an unknown MR low-intensity class encompassing cortical bones, air cavities, and metal artifacts. A coregistered bone probability map was also included in the unknown tissue class. Finally, the GMM prior was constrained over known tissue classes of attenuation maps using unimodal gaussians parameterized over a patient population. RESULTS The results showed that the MLAA-GMM algorithm outperformed the MRAC method by differentiating bones from air gaps and providing more accurate patient-specific attenuation coefficients of soft tissue and lungs. It was found that the MRAC and MLAA-GMM methods resulted in average standardized uptake value errors of -5.4% and -3.5% in the lungs, -7.4% and -5.0% in soft tissues/lesions, and -18.4% and -10.2% in bones, respectively. CONCLUSION The proposed MLAA algorithm is promising for accurate derivation of attenuation maps on time-of-flight PET/MR systems.
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Affiliation(s)
- Abolfazl Mehranian
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland Geneva Neuroscience Centre, University of Geneva, Geneva, Switzerland; and Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen, The Netherlands
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120
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Mehranian A, Zaidi H. Impact of time-of-flight PET on quantification errors in MR imaging-based attenuation correction. J Nucl Med 2015; 56:635-41. [PMID: 25745090 DOI: 10.2967/jnumed.114.148817] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/21/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Time-of-flight (TOF) PET/MR imaging is an emerging imaging technology with great capabilities offered by TOF to improve image quality and lesion detectability. We assessed, for the first time, the impact of TOF image reconstruction on PET quantification errors induced by MR imaging-based attenuation correction (MRAC) using simulation and clinical PET/CT studies. METHODS Standard 4-class attenuation maps were derived by segmentation of CT images of 27 patients undergoing PET/CT examinations into background air, lung, soft-tissue, and fat tissue classes, followed by the assignment of predefined attenuation coefficients to each class. For each patient, 4 PET images were reconstructed: non-TOF and TOF both corrected for attenuation using reference CT-based attenuation correction and the resulting 4-class MRAC maps. The relative errors between non-TOF and TOF MRAC reconstructions were compared with their reference CT-based attenuation correction reconstructions. The bias was locally and globally evaluated using volumes of interest (VOIs) defined on lesions and normal tissues and CT-derived tissue classes containing all voxels in a given tissue, respectively. The impact of TOF on reducing the errors induced by metal-susceptibility and respiratory-phase mismatch artifacts was also evaluated using clinical and simulation studies. RESULTS Our results show that TOF PET can remarkably reduce attenuation correction artifacts and quantification errors in the lungs and bone tissues. Using classwise analysis, it was found that the non-TOF MRAC method results in an error of -3.4% ± 11.5% in the lungs and -21.8% ± 2.9% in bones, whereas its TOF counterpart reduced the errors to -2.9% ± 7.1% and -15.3% ± 2.3%, respectively. The VOI-based analysis revealed that the non-TOF and TOF methods resulted in an average overestimation of 7.5% and 3.9% in or near lung lesions (n = 23) and underestimation of less than 5% for soft tissue and in or near bone lesions (n = 91). Simulation results showed that as TOF resolution improves, artifacts and quantification errors are substantially reduced. CONCLUSION TOF PET substantially reduces artifacts and improves significantly the quantitative accuracy of standard MRAC methods. Therefore, MRAC should be less of a concern on future TOF PET/MR scanners with improved timing resolution.
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Affiliation(s)
- Abolfazl Mehranian
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen, Netherlands; and Geneva Neuroscience Centre, University of Geneva, Geneva, Switzerland
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Kang J, Chang JH, Wilson BC, Veilleux I, Bai Y, DaCosta R, Kim K, Ha S, Lee JG, Kim JS, Lee SG, Kim SM, Lee HJ, Ahn YB, Han S, Yoo Y, Song TK. A prototype hand-held tri-modal instrument for in vivo ultrasound, photoacoustic, and fluorescence imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:034901. [PMID: 25832265 DOI: 10.1063/1.4915146] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Multi-modality imaging is beneficial for both preclinical and clinical applications as it enables complementary information from each modality to be obtained in a single procedure. In this paper, we report the design, fabrication, and testing of a novel tri-modal in vivo imaging system to exploit molecular/functional information from fluorescence (FL) and photoacoustic (PA) imaging as well as anatomical information from ultrasound (US) imaging. The same ultrasound transducer was used for both US and PA imaging, bringing the pulsed laser light into a compact probe by fiberoptic bundles. The FL subsystem is independent of the acoustic components but the front end that delivers and collects the light is physically integrated into the same probe. The tri-modal imaging system was implemented to provide each modality image in real time as well as co-registration of the images. The performance of the system was evaluated through phantom and in vivo animal experiments. The results demonstrate that combining the modalities does not significantly compromise the performance of each of the separate US, PA, and FL imaging techniques, while enabling multi-modality registration. The potential applications of this novel approach to multi-modality imaging range from preclinical research to clinical diagnosis, especially in detection/localization and surgical guidance of accessible solid tumors.
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Affiliation(s)
- Jeeun Kang
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Jin Ho Chang
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Brian C Wilson
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Israel Veilleux
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Yanhui Bai
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Ralph DaCosta
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Kang Kim
- Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine, University of Pittsburgh School of Medicine and Heart and Vascular Institute, University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania 15213, USA
| | - Seunghan Ha
- Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine, University of Pittsburgh School of Medicine and Heart and Vascular Institute, University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania 15213, USA
| | - Jong Gun Lee
- GE Ultrasound Korea, Seongnam 462-807, South Korea
| | | | | | - Sun Mi Kim
- Department of Radiology, Seoul National University of Bundang Hospital, Kyonggi-do, South Korea
| | - Hak Jong Lee
- Department of Radiology, Seoul National University of Bundang Hospital, Kyonggi-do, South Korea
| | - Young Bok Ahn
- Department of Electronic Engineering, Konkuk University, Seoul 143-701, South Korea
| | - Seunghee Han
- Sogang Institute of Advanced Technology, Sogang University, Seoul 121-742, South Korea
| | - Yangmo Yoo
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Tai-Kyong Song
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
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Wehner J, Weissler B, Dueppenbecker PM, Gebhardt P, Goldschmidt B, Schug D, Kiessling F, Schulz V. MR-compatibility assessment of the first preclinical PET-MRI insert equipped with digital silicon photomultipliers. Phys Med Biol 2015; 60:2231-55. [PMID: 25684065 DOI: 10.1088/0031-9155/60/6/2231] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PET (positron emission tomography) with its high sensitivity in combination with MRI (magnetic resonance imaging) providing anatomic information with good soft-tissue contrast is considered to be a promising hybrid imaging modality. However, the integration of a PET detector into an MRI system is a challenging task since the MRI system is a sensitive device for external disturbances and provides a harsh environment for electronic devices. Consequently, the PET detector has to be transparent for the MRI system and insensitive to electromagnetic disturbances. Due to the variety of MRI protocols imposing a wide range of requirements regarding the MR-compatibility, an extensive study is mandatory to reliably assess worst-case interference phenomena between the PET detector and the MRI scanner. We have built the first preclinical PET insert, designed for a clinical 3 T MRI, using digital silicon photomultipliers (digital SiPM, type DPC 3200-22, Philips Digital Photon Counting). Since no thorough interference investigation with this new digital sensor has been reported so far, we present in this work such a comprehensive MR-compatibility study. Acceptable distortion of the B0 field homogeneity (volume RMS = 0.08 ppm, peak-to-peak value = 0.71 ppm) has been found for the PET detector installed. The signal-to-noise ratio degradation stays between 2-15% for activities up to 21 MBq. Ghosting artifacts were only found for demanding EPI (echo planar imaging) sequences with read-out gradients in Z direction caused by additional eddy currents originated from the PET detector. On the PET side, interference mainly between the gradient system and the PET detector occurred: extreme gradient tests were executed using synthetic sequences with triangular pulse shape and maximum slew rate. Under this condition, a relative degradation of the energy (⩽10%) and timing (⩽15%) resolution was noticed. However, barely measurable performance deterioration occurred when morphological MRI protocols are conducted certifying that the overall PET performance parameters remain unharmed.
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Affiliation(s)
- J Wehner
- Department for Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging Systems, RWTH Aachen University, Pauwelsstrasse 19, 52074 Aachen, Germany
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Rischpler C, Langwieser N, Souvatzoglou M, Batrice A, van Marwick S, Snajberk J, Ibrahim T, Laugwitz KL, Nekolla SG, Schwaiger M. PET/MRI early after myocardial infarction: evaluation of viability with late gadolinium enhancement transmurality vs. 18F-FDG uptake. Eur Heart J Cardiovasc Imaging 2015; 16:661-9. [PMID: 25680385 DOI: 10.1093/ehjci/jeu317] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/03/2014] [Indexed: 01/03/2023] Open
Abstract
AIMS F-18 fluorodeoxyglucose (FDG) myocardial PET imaging is since more than two decades considered to delineate glucose utilization in dysfunctional but viable cardiomyocytes. Late gadolinium enhancement (LGE) MRI was introduced more than a decade ago and identifies increased extravascular space in areas of infarction and scar. Although the physiological foundation differs, both approaches are valuable in the prediction of functional outcome of the left ventricle, but synergistic effects are yet unknown. We aimed to compare the improvement of LV function after 6 months based on the regional FDG uptake and the transmurality of scar by LGE in patients early after acute myocardial infarction (AMI). METHODS AND RESULTS Twenty-eight patients with primary AMI underwent simultaneous PET/MRI for assessment of regional FDG uptake and degree of LGE transmurality 5-7 days after PCI. Follow-up by MRI was performed in 20 patients 6 months later. Myocardium was defined 'PET viable' based on the established threshold of ≥ 50% FDG uptake compared with remote myocardium or as 'MRI viable' when LGE transmurality of ≤ 50% was present. Regional wall motion was measured by MRI. Ninety-five dysfunctional segments were further analysed regarding regional wall motion recovery. There was a substantial intermethod agreement for segmental LGE transmurality and reduction of FDG uptake (κ = 0.65). 'PET viable' and 'MRI viable' segments showed a lower wall motion abnormality score (PET: initial: 1.4 ± 0.6 vs. 1.9 ± 0.8, P < 0.008; follow-up: 0.5 ± 0.7 vs. 1.5 ± 1.0, P < 0.0001; MRI: initial: 1.5 ± 0.6 vs. 2.0 ± 0.8, P < 0.002; follow-up: 0.7 ± 0.8 vs. 1.6 ± 1.0, P < 0.0001) and a better regional wall motion improvement (PET: -0.9 ± 0.7 vs. -0.4 ± 0.7, P < 0.0007; MRI: -0.8 ± 0.7 vs. -0.4 ± 0.7, P < 0.009) compared with 'PET non-viable' or 'MRI non-viable' segments, respectively. Eighteen per cent of the dysfunctional segments showed discrepant findings ('PET non-viable' but 'MRI viable'). At follow-up, the regional wall motion of these segments was inferior compared with 'PET viable/MRI viable' segments (1.1 ± 0.8 vs. 0.5 ± 0.7, P < 0.01), had an inferior functional recovery (-0.5 ± 0.6 vs. -0.9 ± 0.7, P < 0.03), but showed no difference compared with concordant 'PET non-viable/MRI non-viable' segments. CONCLUSION The simultaneous assessment of LGE and FDG uptake using a hybrid PET/MRI system is feasible. The established PET and MRI 'viability' parameter prior to revascularization therapy also predicts accurately the regional outcome of wall motion after AMI. In a small proportion of segments with discrepant FDG PET and LGE MRI findings, FDG uptake was a better predictor for functional recovery.
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Affiliation(s)
- Christoph Rischpler
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany DZKH (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.), Partner Site Munich Heart Alliance, Munich, Germany
| | - Nicolas Langwieser
- Medizinische Klinik und Poliklinik I, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Michael Souvatzoglou
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Anja Batrice
- Medizinische Klinik und Poliklinik I, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sandra van Marwick
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Julian Snajberk
- Medizinische Klinik und Poliklinik I, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Tareq Ibrahim
- Medizinische Klinik und Poliklinik I, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Karl-Ludwig Laugwitz
- Medizinische Klinik und Poliklinik I, Klinikum rechts der Isar, Technische Universität München, Munich, Germany DZKH (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.), Partner Site Munich Heart Alliance, Munich, Germany
| | - Stephan G Nekolla
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany DZKH (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.), Partner Site Munich Heart Alliance, Munich, Germany
| | - Markus Schwaiger
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany DZKH (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.), Partner Site Munich Heart Alliance, Munich, Germany
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Yoo HJ, Lee JS, Lee JM. Integrated whole body MR/PET: where are we? Korean J Radiol 2015; 16:32-49. [PMID: 25598673 PMCID: PMC4296276 DOI: 10.3348/kjr.2015.16.1.32] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/09/2014] [Indexed: 01/16/2023] Open
Abstract
Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.
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Affiliation(s)
- Hye Jin Yoo
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jae Sung Lee
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea
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Computed tomography, magnetic resonance imaging and FDG positron emission tomography in the management of vulvar malignancies. Eur Radiol 2014; 25:1267-78. [PMID: 25477274 DOI: 10.1007/s00330-014-3530-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 10/11/2014] [Accepted: 11/19/2014] [Indexed: 01/16/2023]
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126
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Fan L, Sher A, Kohan A, Vercher-Conejero J, Rajiah P. PET/MRI in Lung Cancer. Semin Roentgenol 2014; 49:291-303. [DOI: 10.1053/j.ro.2014.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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127
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Lai CH, Lin G, Yen TC, Liu FY. Molecular imaging in the management of gynecologic malignancies. Gynecol Oncol 2014; 135:156-62. [DOI: 10.1016/j.ygyno.2014.07.092] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 07/19/2014] [Indexed: 10/25/2022]
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129
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Hu Z, Yang W, Liu H, Wang K, Bao C, Song T, Wang J, Tian J. From PET/CT to PET/MRI: advances in instrumentation and clinical applications. Mol Pharm 2014; 11:3798-809. [PMID: 25058336 DOI: 10.1021/mp500321h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Multimodality imaging of positron emission tomography/computed tomography (PET/CT) provides both metabolic information and the anatomic structure, which is significantly superior to either PET or CT alone and has greatly improved its clinical applications. Because of the higher soft-tissue contrast of magnetic resonance imaging (MRI) and no extra ionizing radiation, PET/MRI imaging is the hottest topic currently. PET/MRI is swiftly making its way into clinical practice. However, it has many technical difficulties to overcome, such as photomultiplier tubes, which cannot work properly in a magnetic field, and the inability to provide density information on the object for attenuation correction. This paper introduces the technique process of PET/MRI and summarizes its clinical applications, including imaging in oncology, neurology, and cardiology.
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Affiliation(s)
- Zhenhua Hu
- Institute of Automation, Chinese Academy of Sciences , Beijing 100190, China
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130
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Weissler B, Gebhardt P, Lerche CW, Wehner J, Solf T, Goldschmidt B, Mackewn JE, Marsden PK, Kiessling F, Perkuhn M, Heberling D, Schulz V. MR compatibility aspects of a silicon photomultiplier-based PET/RF insert with integrated digitisation. Phys Med Biol 2014; 59:5119-39. [DOI: 10.1088/0031-9155/59/17/5119] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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131
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Martinez-Rios C, Muzic RF, DiFilippo FP, Hu L, Rubbert C, Herrmann KA. Artifacts and diagnostic pitfalls in positron emission tomography-magnetic resonance imaging. Semin Roentgenol 2014; 49:255-70. [PMID: 25497910 DOI: 10.1053/j.ro.2014.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - Raymond F Muzic
- Department of Radiology, Case Western Reserve University, Cleveland, OH; Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH
| | - Frank P DiFilippo
- Department of Nuclear Medicine, Cleveland Clinic, Imaging Institute, Cleveland, OH
| | | | - Christian Rubbert
- Institute of Diagnostic and Interventional Radiology, University Hospitals, Düsseldorf, Germany
| | - Karin A Herrmann
- Department of Radiology, Case Western Reserve University, Cleveland, OH; Department of Radiology, University Hospitals Case Medical Center, Cleveland, OH.
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Son YD, Cho ZH, Choi EJ, Kim JH, Kim HK, Lee SY, Chi JG, Park CW, Kim JH, Kim YB. Individually Differentiated Serotonergic Raphe Nuclei Measured with Brain PET/MR Imaging. Radiology 2014; 272:541-8. [DOI: 10.1148/radiol.14131547] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Gounant V, Khalil A, Créquit P, Lavole A, Ruppert AM, Antoine M, Milleron B, Wislez M, Carette MF, Assouad J, Cadranel J. 2014 update on non-small cell lung cancer (excluding diagnosis). Diagn Interv Imaging 2014; 95:721-5. [PMID: 25027710 DOI: 10.1016/j.diii.2014.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Lung cancer (LC) is a major public health issue because of its frequency, but especially because of the severity of this disease. The epidemiology has changed with an increased incidence in non-smokers and women. The ATS/ERS/IASLC classification of adenocarcinomas was modified in 2011, and they are now the most frequent histological subtype. More than half the cases of LC are diagnosed at the metastatic stage. Biopsies must provide tissue samples that are quantitatively large enough and of a good enough quality for diagnosis and to search for biomarkers. When the cancer seems to be localized, precise staging must be obtained. Treatment is based on the TNM classification. In localized stages, lobectomy associated with lymph node dissection is the standard therapy. Intraoperative chemotherapy improves survival in case of lymph node infiltration. Stereotactic radiation therapy and radiofrequency can be considered as specific cases. In cases with local progression, treatment is more controversial. In the presence of metastases, the goal is not a cure, but improving survival and quality of life. Numerous advances have been made with personalized treatment, (in particular in relation to the histological type and oncogenic addiction in tumors, access to new drugs, and improved management). Clinical research in thoracic cancer is very active. The fight against tobacco should remain a priority.
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Affiliation(s)
- V Gounant
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France; Service de chirurgie thoracique, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France.
| | - A Khalil
- Service de radiologie, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - P Créquit
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - A Lavole
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - A M Ruppert
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - M Antoine
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service d'anatomie pathologique, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - B Milleron
- Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - M Wislez
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - M F Carette
- Service de radiologie, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - J Assouad
- Service de chirurgie thoracique, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
| | - J Cadranel
- Sorbonne Universités, UPMC Université Paris 06, GRC n(o) 04, Theranoscan, 75252 Paris, France; Service de pneumologie, Centre expert en oncologie thoracique et maladies pulmonaires rares, Hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France
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Siddiqui F, Yao M. Application of fluorodeoxyglucose positron emission tomography in the management of head and neck cancers. World J Radiol 2014; 6:238-251. [PMID: 24976927 PMCID: PMC4072811 DOI: 10.4329/wjr.v6.i6.238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/16/2014] [Accepted: 03/14/2014] [Indexed: 02/06/2023] Open
Abstract
The use of fluorodeoxyglucose positron emission tomography (FDG PET) scan technology in the management of head and neck cancers continues to increase. We discuss the biology of FDG uptake in malignant lesions and also discuss the physics of PET imaging. The various parameters described to quantify FDG uptake in cancers including standardized uptake value, metabolic tumor volume and total lesion glycolysis are presented. PET scans have found a significant role in the diagnosis and staging of head and neck cancers. They are also being increasingly used in radiation therapy treatment planning. Many groups have also used PET derived values to serve as prognostic indicators of outcomes including loco-regional control and overall survival. FDG PET scans are also proving very useful in assessing the efficacy of treatment and management and follow-up of head and neck cancer patients. This review article focuses on the role of FDG-PET computed tomography scans in these areas for squamous cell carcinoma of the head and neck. We present the current state of the art and speculate on the future applications of this technology including protocol development, newer imaging methods such as combined magnetic resonance and PET imaging and novel radiopharmaceuticals that can be used to further study tumor biology.
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Lee ES, Lee JM. Imaging diagnosis of pancreatic cancer: A state-of-the-art review. World J Gastroenterol 2014; 20:7864-7877. [PMID: 24976723 PMCID: PMC4069314 DOI: 10.3748/wjg.v20.i24.7864] [Citation(s) in RCA: 226] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/13/2013] [Accepted: 01/05/2014] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer (PC) remains one of the deadliest cancers worldwide, and has a poor, five-year survival rate of 5%. Although complete surgical resection is the only curative therapy for pancreatic cancer, less than 20% of newly-diagnosed patients undergo surgical resection with a curative intent. Due to the lack of early symptoms and the tendency of pancreatic adenocarcinoma to invade adjacent structures or to metastasize at an early stage, many patients with pancreatic cancer already have advanced disease at the time of their diagnosis and, therefore, there is a high mortality rate. To improve the patient survival rate, early detection of PC is critical. The diagnosis of PC relies on computed tomography (CT) and/or magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP), or biopsy or fine-needle aspiration using endoscopic ultrasound (EUS). Although multi-detector row computed tomography currently has a major role in the evaluation of PC, MRI with MRCP facilitates better detection of tumors at an early stage by allowing a comprehensive analysis of the morphological changes of the pancreas parenchyma and pancreatic duct. The diagnosis could be improved using positron emission tomography techniques in special conditions in which CT and EUS are not completely diagnostic. It is essential for clinicians to understand the advantages and disadvantages of the various pancreatic imaging modalities in order to be able to make optimal treatment and management decisions. Our study investigates the current role and innovative techniques of pancreatic imaging focused on the detection of pancreatic cancer.
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Hess S, Blomberg BA, Rakheja R, Friedman K, Kwee TC, Høilund-Carlsen PF, Alavi A. A brief overview of novel approaches to FDG PET imaging and quantification. Clin Transl Imaging 2014. [DOI: 10.1007/s40336-014-0062-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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139
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Zakaria R, Das K, Bhojak M, Radon M, Walker C, Jenkinson MD. The role of magnetic resonance imaging in the management of brain metastases: diagnosis to prognosis. Cancer Imaging 2014; 14:8. [PMID: 25608557 PMCID: PMC4331840 DOI: 10.1186/1470-7330-14-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 02/11/2014] [Indexed: 11/20/2022] Open
Abstract
This article reviews the different MRI techniques available for the diagnosis, treatment and monitoring of brain metastases with a focus on applying advanced MR techniques to practical clinical problems. Topics include conventional MRI sequences and contrast agents, functional MR imaging, diffusion weighted MR, MR spectroscopy and perfusion MR. The role of radiographic biomarkers is discussed as well as future directions such as molecular imaging and MR guided high frequency ultrasound.
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140
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Alf MF, Duarte JMN, Lei H, Krämer SD, Mlynarik V, Schibli R, Gruetter R. MRS glucose mapping and PET joining forces: re-evaluation of the lumped constant in the rat brain under isoflurane anaesthesia. J Neurochem 2014; 129:672-82. [PMID: 24471521 DOI: 10.1111/jnc.12667] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 01/22/2014] [Accepted: 01/24/2014] [Indexed: 12/17/2022]
Abstract
Although numerous positron emission tomography (PET) studies with (18) F-fluoro-deoxyglucose (FDG) have reported quantitative results on cerebral glucose kinetics and consumption, there is a large variation between the absolute values found in the literature. One of the underlying causes is the inconsistent use of the lumped constants (LCs), the derivation of which is often based on multiple assumptions that render absolute numbers imprecise and errors hard to quantify. We combined a kinetic FDG-PET study with magnetic resonance spectroscopic imaging (MRSI) of glucose dynamics in Sprague-Dawley rats to obtain a more comprehensive view of brain glucose kinetics and determine a reliable value for the LC under isoflurane anaesthesia. Maps of Tmax /CMRglc derived from MRSI data and Tmax determined from PET kinetic modelling allowed to obtain an LC-independent CMRglc . The LC was estimated to range from 0.33 ± 0.07 in retrosplenial cortex to 0.44 ± 0.05 in hippocampus, yielding CMRglc between 62 ± 14 and 54 ± 11 μmol/min/100 g, respectively. These newly determined LCs for four distinct areas in the rat brain under isoflurane anaesthesia provide means of comparing the growing amount of FDG-PET data available from translational studies.
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Affiliation(s)
- Malte F Alf
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Center for Radiopharmaceutical Sciences of ETH Zurich, Zurich, Switzerland
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Sneddon D, Poulsen SA. Agents described in the Molecular Imaging and Contrast Agent Database for imaging carbonic anhydrase IX expression. J Enzyme Inhib Med Chem 2014; 29:753-63. [PMID: 24506208 DOI: 10.3109/14756366.2013.848205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Carbonic anhydrase IX (CA IX) is selectively expressed in a range of hypoxic tumours and is a validated endogenous hypoxia marker with prognostic significance; hence, CA IX is of great interest as a molecular imaging target in oncology. In this review, we present an overview of the different imaging agents and imaging modalities that have been applied for the in vivo detection of CA IX. The imaging agents reviewed are all entries in the Molecular Imaging and Contrast Agent Database (MICAD) and comprise antibody, antibody fragments and small molecule imaging agents. The effectiveness of these agents for imaging CA IX in vivo gave variable performance; however, a number of agents proved very capable. As molecular imaging has become indispensable in current medical practice we anticipate that the clinical significance of CA IX will see continued development and improvements in imaging agents for targeting this enzyme.
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Affiliation(s)
- Deborah Sneddon
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane, Queensland , Australia
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142
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Hess S, Blomberg BA, Zhu HJ, Høilund-Carlsen PF, Alavi A. The pivotal role of FDG-PET/CT in modern medicine. Acad Radiol 2014; 21:232-49. [PMID: 24439337 DOI: 10.1016/j.acra.2013.11.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 12/21/2022]
Abstract
The technology behind positron emission tomography (PET) and the most widely used tracer, 2-deoxy-2-[18F]fluoro-D-glucose (FDG), were both conceived in the 1970s, but the latest decade has witnessed a rapid emergence of FDG-PET as an effective imaging technique. This is not least due to the emergence of hybrid scanners combining PET with computed tomography (PET/CT). Molecular imaging has enormous potential for advancing biological research and patient care, and FDG-PET/CT is currently the most widely used technology in this domain. In this review, we discuss contemporary applications of FDG-PET and FDG-PET/CT as well as novel developments in quantification and potential future indications including the emerging new modality PET/magnetic resonance imaging.
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Wehner J, Weissler B, Dueppenbecker P, Gebhardt P, Schug D, Ruetten W, Kiessling F, Schulz V. PET/MRI insert using digital SiPMs: Investigation of MR-compatibility. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT 2014; 734:116-121. [PMID: 25843999 PMCID: PMC4376059 DOI: 10.1016/j.nima.2013.08.077] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work, we present an initial MR-compatibility study performed with the world's first preclinical PET/MR insert based on fully digital silicon photo multipliers (dSiPM). The PET insert allows simultaneous data acquisition of both imaging modalities and thus enables the true potential of hybrid PET/MRI. Since the PET insert has the potential to interfere with all of the MRI's subsystems (strong magnet, gradients system, radio frequency (RF) system) and vice versa, interference studies on both imaging systems are of great importance to ensure an undisturbed operation. As a starting point to understand the interference, we performed signal-to-noise ratio (SNR) measurements as well as dedicated noise scans on the MRI side to characterize the influence of the PET electronics on the MR receive chain. Furthermore, improvements of sub-components' shielding of the PET system are implemented and tested inside the MRI. To study the influence of the MRI on the PET performance, we conducted highly demanding stress tests with gradient and RF dominated MR sequences. These stress tests unveil a sensitivity of the PET's electronics to gradient switching.
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Affiliation(s)
- Jakob Wehner
- Physics of Molecular Imaging Systems, Department for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Bjoern Weissler
- Physics of Molecular Imaging Systems, Department for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
- Philips Research Europe, Aachen, Germany
| | - Peter Dueppenbecker
- Philips Research Europe, Aachen, Germany
- King's College London, London, United Kingdom
| | | | - David Schug
- Physics of Molecular Imaging Systems, Department for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | | | - Fabian Kiessling
- Department for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Volkmar Schulz
- Physics of Molecular Imaging Systems, Department for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
- Philips Research Europe, Aachen, Germany
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Purohit BS, Dulguerov P, Burkhardt K, Becker M. Dedifferentiated laryngeal chondrosarcoma: Combined morphologic and functional imaging with positron-emission tomography/magnetic resonance imaging. Laryngoscope 2013; 124:E274-7. [DOI: 10.1002/lary.24518] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Bela S. Purohit
- Department of Radiology; Geneva University Hospital; Geneva Switzerland
| | - Pavel Dulguerov
- Department of Otorhinolaryngology-Head and Neck Surgery; Geneva University Hospital; Geneva Switzerland
| | - Karim Burkhardt
- Department of Clinical Pathology; Geneva University Hospital; Geneva Switzerland
| | - Minerva Becker
- Department of Radiology; Geneva University Hospital; Geneva Switzerland
- Department of Otorhinolaryngology-Head and Neck Surgery; Geneva University Hospital; Geneva Switzerland
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145
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Giganti F, De Cobelli F, Canevari C, Orsenigo E, Gallivanone F, Esposito A, Castiglioni I, Ambrosi A, Albarello L, Mazza E, Gianolli L, Staudacher C, Del Maschio A. Response to chemotherapy in gastric adenocarcinoma with diffusion-weighted MRI and (18) F-FDG-PET/CT: correlation of apparent diffusion coefficient and partial volume corrected standardized uptake value with histological tumor regression grade. J Magn Reson Imaging 2013; 40:1147-57. [PMID: 24214734 DOI: 10.1002/jmri.24464] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 09/21/2013] [Indexed: 02/06/2023] Open
Abstract
PURPOSE To assess whether changes in diffusion-weighted MRI (DW-MRI) and (18) F-fluoro-2-deoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT), correlate with treatment response to neoadjuvant therapy (NT), as expressed by tumor regression grade (TRG), from locally advanced gastric adenocarcinoma (GA). MATERIALS AND METHODS Seventeen patients underwent both DW-MRI and (18) F-FDG-PET/CT scans before and after the end of NT. Apparent diffusion coefficient (ADC) and mean standardized uptake value (SUV) corrected for partial volume effect (PVC-SUVBW-mean ) were evaluated and compared with histopathological TRG. RESULTS Pre- and post-NT and percentage changes for ADC and PVC-SUVBW-mean were assessed. Post-NT ADC and ΔADC showed a significant inverse correlation with TRG (r = -0.71; P = 0.0011 and r = -0.78; P = 0.00020, respectively) and significant differences in their mean values were found between responders (TRG 1-2-3) and nonresponders (TRG 4-5) (P = 0.0009; P = 0.000082, respectively). No correlations with TRG were found for pre-NT ADC and for all PVC-SUVBW-mean values as well as between ΔADC and Δ PVC-SUVBW-mean . CONCLUSION DW-MRI seems more accurate than (18) F-FDG-PET/CT and ADC modifications may represent a reproducible tool to assess tumor response for GA.
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Affiliation(s)
- Francesco Giganti
- Department of Radiology and Center for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy
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Zaidi H. A pivotal time for hybrid PET/MR imaging technology. J Am Coll Radiol 2013; 10:878-81. [PMID: 24183554 DOI: 10.1016/j.jacr.2013.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 08/06/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland; Geneva Neuroscience Center, Geneva University, Geneva, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Netherlands.
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Calcagno C, Ramachandran S, Izquierdo-Garcia D, Mani V, Millon A, Rosenbaum D, Tawakol A, Woodward M, Bucerius J, Moshier E, Godbold J, Kallend D, Farkouh ME, Fuster V, Rudd JHF, Fayad ZA. The complementary roles of dynamic contrast-enhanced MRI and 18F-fluorodeoxyglucose PET/CT for imaging of carotid atherosclerosis. Eur J Nucl Med Mol Imaging 2013; 40:1884-93. [PMID: 23942908 DOI: 10.1007/s00259-013-2518-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/11/2013] [Indexed: 12/15/2022]
Abstract
PURPOSE Inflammation and neovascularization in vulnerable atherosclerotic plaques are key features for severe clinical events. Dynamic contrast-enhanced (DCE) MRI and FDG PET are two noninvasive imaging techniques capable of quantifying plaque neovascularization and inflammatory infiltrate, respectively. However, their mutual role in defining plaque vulnerability and their possible overlap has not been thoroughly investigated. We studied the relationship between DCE-MRI and (18)F-FDG PET data from the carotid arteries of 40 subjects with coronary heart disease (CHD) or CHD risk equivalent, as a substudy of the dal-PLAQUE trial (NCT00655473). METHODS The dal-PLAQUE trial was a multicenter study that evaluated dalcetrapib, a cholesteryl ester transfer protein modulator. Subjects underwent anatomical MRI, DCE-MRI and (18)F-FDG PET. Only baseline imaging and biomarker data (before randomization) from dal-PLAQUE were used as part of this substudy. Our primary goal was to evaluate the relationship between DCE-MRI and (18)F-FDG PET data. As secondary endpoints, we evaluated the relationship between (a) PET data and whole-vessel anatomical MRI data, and (b) DCE-MRI and matching anatomical MRI data. All correlations were estimated using a mixed linear model. RESULTS We found a significant inverse relationship between several perfusion indices by DCE-MRI and (18)F-FDG uptake by PET. Regarding our secondary endpoints, there was a significant relationship between plaque burden measured by anatomical MRI with several perfusion indices by DCE-MRI and (18)F-FDG uptake by PET. No relationship was found between plaque composition by anatomical MRI and DCE-MRI or (18)F-FDG PET metrics. CONCLUSION In this study we observed a significant, weak inverse relationship between inflammation measured as (18)F-FDG uptake by PET and plaque perfusion by DCE-MRI. Our findings suggest that there may be a complex relationship between plaque inflammation and microvascularization during the different stages of plaque development. (18)F-FDG PET and DCE-MRI may have complementary roles in future clinical practice in identifying subjects at high risk of cardiovascular events.
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Affiliation(s)
- Claudia Calcagno
- Translational and Molecular Imaging Institute, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1234, New York, NY, 10029, USA
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Nensa F, Poeppel TD, Beiderwellen K, Schelhorn J, Mahabadi AA, Erbel R, Heusch P, Nassenstein K, Bockisch A, Forsting M, Schlosser T. Hybrid PET/MR Imaging of the Heart: Feasibility and Initial Results. Radiology 2013; 268:366-73. [DOI: 10.1148/radiol.13130231] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Jadvar H, Colletti PM. Competitive advantage of PET/MRI. Eur J Radiol 2013; 83:84-94. [PMID: 23791129 DOI: 10.1016/j.ejrad.2013.05.028] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 05/20/2013] [Accepted: 05/20/2013] [Indexed: 02/08/2023]
Abstract
Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved.
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Affiliation(s)
- Hossein Jadvar
- Division of Nuclear Medicine, Department of Radiology, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA.
| | - Patrick M Colletti
- Division of Nuclear Medicine, Department of Radiology, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
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Abstract
Hybrid PET/magnetic resonance (MR) imaging, which combines the excellent anatomic information and functional MR imaging parameters with the metabolic and molecular information obtained with PET, may be superior to PET/computed tomography or MR imaging alone for a wide range of disease conditions. This review highlights potential clinical applications in neurologic, cardiovascular, and musculoskeletal disease conditions, with special attention to applications in oncologic imaging.
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