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Choi CH, Felder J, Lerche C, Shah NJ. MRI Coil Development Strategies for Hybrid MR-PET Systems: A Review. IEEE Rev Biomed Eng 2024; 17:342-350. [PMID: 37015609 DOI: 10.1109/rbme.2022.3227337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Simultaneously operating MR-PET systems have the potential to provide synergetic multi-parametric information, and, as such, interest surrounding their use and development is increasing. However, despite the potential advantages offered by fully combined MR-PET systems, implementing this hybrid integration is technically laborious, and any factors degrading the quality of either modality must be circumvented to ensure optimal performance. In order to attain the best possible quality from both systems, most full MR-PET integrations tend to place the shielded PET system inside the MRI system, close to the target volume of the subject. The radiofrequency (RF) coil used in MRI systems is a key factor in determining the quality of the MR images, and, in simultaneous acquisition, it is generally positioned inside the PET system and PET imaging region, potentially resulting in attenuation and artefacts in the PET images. Therefore, when designing hybrid MR-PET systems, it is imperative that consideration be given to the RF coils inside the PET system. In this review, we present current state-of-the-art RF coil designs used for hybrid MR-PET experiments and discuss various design strategies for constructing PET transparent RF coils.
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Mada MO, Hindmarch P, Stirling J, Davies J, Brian D, Barnes A, Hammers A, Gulliver N, Herholz K, O’Brien J, Taylor JP. Competencies and training of radiographers and technologists for PET/MR imaging - a study from the UK MR-PET network. Eur J Hybrid Imaging 2020; 4:1. [PMID: 32025619 PMCID: PMC6976550 DOI: 10.1186/s41824-019-0070-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 12/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND After the success of PET/CT as a clinical diagnostic tool, the introduction of PET/MRI is a natural development aimed at further improving combined diagnostic imaging and reduced ionising radiation dose for half-body imaging. As with PET and CT, the combination of PET and MRI presents a series of issues that need to be addressed regarding workforce training and education. At present, there is a lack of agreement over the competencies, training requirements and educational pathways needed for PET/MRI operation. In the UK, following the establishment of the MR-PET imaging network, a task force was created to investigate the status of the workforce training, identify gaps and make recommendations regarding staff training. To do this, we ran a national survey on the status of the workforce training and the local practices across the UK's seven PET/MRI sites, reviewed the literature, and convened a panel of experts, to assess all the evidence and make recommendations regarding PET/MRI competencies and training of nuclear medicine technologists and radiographers. RESULTS There is limited literature available specifically on competencies and training for technologists and radiographers. The recommendations on the topic needed revisiting and adapting to the UK MR-PET network. The online survey confirmed the need for developing PET/MRI competencies and training pathways. Local organisational structures and practices were shared across the seven sites, based on models derived from experience outside the UK. The panel of experts agreed on the need for PET/MRI competencies and training strategies. Professional organisations started collaborative discussions with partners from both Nuclear Medicine and Radiography to set training priorities. Multidisciplinary collaboration and partnership were suggested as a key to a successful implementation of competencies and training. CONCLUSIONS The report identified the need for establishing competencies for the PET/MRI workforce, particularly for technologists and radiographers. It also helped defining these competencies as well as identifying the demand for bespoke training and the development of local and national courses to be implemented to fulfil this new training need.
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Affiliation(s)
- Marius Ovidiu Mada
- University of Cambridge, Wolfson Brain Imaging Centre, Box 65, Adrian Way, Cambridge, CB20QQ UK
| | - Paula Hindmarch
- Positron Emission Tomography Centre, Newcastle University, Building 15, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 6BE UK
| | - James Stirling
- King’s College London, PET Centre, 1st Floor Lambeth Wing, St Thomas’ Hospital, London, SE1 7EH UK
| | - James Davies
- Invicro, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN UK
| | - David Brian
- University of Edinburgh, Edinburgh Imaging Facility QMRI, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ UK
| | - Anna Barnes
- UCL Hospitals NHS Foundation Trust, 235 Euston Road, London, NW1 2BU UK
| | - Alexander Hammers
- King’s College London, PET Centre, 1st Floor Lambeth Wing, St Thomas’ Hospital, London, SE1 7EH UK
| | - Nick Gulliver
- Department of Nuclear Medicine & PET-CT, King’s College Hospital NHS Foundation Trust, Denmark Hill, London, SE5 9RS UK
| | - Karl Herholz
- University of Manchester, Wolfson Molecular Imaging Centr, 27 Palantine Road, Manchester, M20 3LJ UK
| | - John O’Brien
- University Department of Psychiatry, University of Cambridge, Cambridge Biomedical Campus, Box 189, Adrian Way, Cambridge, CB20QQ UK
| | - John-Paul Taylor
- Newcastle University, Institute of Neuroscience, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL UK
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Jentzen W, Phaosricharoen J, Gomez B, Hetkamp P, Stebner V, Binse I, Kinner S, Herrmann K, Sabet A, Nagarajah J. Quantitative performance of 124I PET/MR of neck lesions in thyroid cancer patients using 124I PET/CT as reference. EJNMMI Phys 2018; 5:13. [PMID: 30022353 PMCID: PMC6051951 DOI: 10.1186/s40658-018-0214-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/17/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In patients with differentiated thyroid cancer (DTC), serial 124I PET/CT imaging is, for instance, used to assess the absorbed (radiation) dose to lesions. Frequently, the lesions are located in the neck and they are close to or surrounded by different tissue types. In contrast to PET/CT, MR-based attenuation correction in PET/MR may be therefore challenging in the neck region. The aim of this retrospective study was to assess the quantitative performance of 124I PET/MRI of neck lesions by comparing the MR-based and CT-based 124I activity concentrations (ACs). Sixteen DTC patients underwent PET/CT scans at 24 and 120 h after administration of about 25 MBq 124I. Approximately 1 h before or after PET/CT examination, each patient additionally received a 24-h PET/MR scan and sometimes a 120-h PET/MR scan. PET images were reconstructed using the respective attenuation correction approach. Appropriate reconstruction parameters and corrections were used to harmonize the reconstructed PET images to provide, for instance, similar spatial resolution. For each lesion, two types of ACs were ascertained: the maximum AC (max-AC) and an average AC (avg-AC). The avg-AC is the average activity concentration obtained within a spherical volume of interest with a diameter of 7 mm, equaling the PET scanner resolution. For each type of AC, the percentage AC difference between MR-based and CT-based ACs was determined and Lin's concordance correlation analysis was applied. Quantitative performance was considered acceptable if the standard deviation was ± 25% (precision), and the mean value was within ± 10% (accuracy). RESULTS The avg-ACs (max-ACs within parentheses) of 74 lesions ranged from 0.20 (0.33) to 657 (733) kBq/mL. Excluding two lesions with ACs of approximately 1 kBq/mL, the mean (median) ± standard deviation (range) was - 4% (- 5%) ± 14% (- 28 to 29%) for the avg-AC and - 9% (- 11%) ± 14% (- 33 to 33%) for the max-AC. Lin's concordance correlation coefficients were ≥ 0.97, indicating substantial AC agreement. CONCLUSIONS Quantification of lesions in the neck region using 124I PET/MR showed acceptable quantitation performance to 124I PET/CT for AC above 1 kBq/mL. The PET/MRI-based 124I ACs in the neck region can be therefore reliably used in pre-therapy dosimetry planning.
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Affiliation(s)
- Walter Jentzen
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Jinda Phaosricharoen
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Benedikt Gomez
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Philipp Hetkamp
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Vanessa Stebner
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Ina Binse
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Sonja Kinner
- Department of Radiology, University of Duisburg-Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | - Amir Sabet
- Department of Nuclear Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - James Nagarajah
- Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstrasse 55, D-45122, Essen, Germany.
- Radboudumc, Department of Radiology and Nuclear Medicine, Nijmegen, The Netherlands.
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Polanec SH, Andrzejewski P, Baltzer PAT, Helbich TH, Stiglbauer A, Georg D, Karanikas G, Susani M, Wadsak W, Margreiter M, Mitterhauser M, Brader P, Pinker K. Multiparametric [11C]Acetate positron emission tomography-magnetic resonance imaging in the assessment and staging of prostate cancer. PLoS One 2017; 12:e0180790. [PMID: 28719629 PMCID: PMC5515396 DOI: 10.1371/journal.pone.0180790] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 06/21/2017] [Indexed: 02/06/2023] Open
Abstract
Background The aim of this study was to evaluate whether MP [11C]Acetate PET-MRI enables an accurate differentiation of benign and malignant prostate tumors as well as local and distant staging. Materials and methods Fifty-six consecutive patients fulfilling the following criteria were included in this IRB-approved prospective study: elevated PSA levels or suspicious findings at digital rectal examination or TRUS; and histopathological verification. All patients underwent MP [11C]Acetate PET-MRI of the prostate performed on separate scanners with PET/CT using [11C]Acetate and 3T MP MR imaging. Appropriate statistical tests were used to determine diagnostic accuracy, local and distant staging. Results MP imaging with two MRI parameters (T2w and DWI) achieved the highest sensitivity, specificity, and diagnostic accuracy of 95%, 68.8%, and 88%, with an AUC of 0.82 for primary PCa detection. Neither assessments with a single parameter (AUC, 0.54–0.79), nor different combinations with up to five parameters (AUC, 0.67–0.79) achieved equally good results. MP [11C]Acetate PET-MRI improved local staging with a sensitivity, specificity, and diagnostic accuracy of 100%, 96%, and 97% compared to MRI alone with 72.2%, 100%, and 95.5%. MP [11C]Acetate PET-MRI correctly detected osseous and liver metastases in five patients. Conclusions MP [11C]Acetate PET-MRI merges morphologic with functional information, and allows insights into tumor biology. MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) yields the highest diagnostic accuracy. The addition of more parameters does not improve diagnostic accuracy of primary PCa detection. MP [11C]Acetate PET-MRI facilitates improved local and distant staging, providing “one-stop” staging in patients with primary PCa, and therefore has the potential to improve therapy. Patient summary In this report we investigated MP [11C]Acetate PET-MRI for detection, local and distant staging of prostate cancer. We demonstrate that MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) achieves the best diagnostic accuracy for primary prostate cancer detection and that MP [11C]Acetate PET-MRI enables an improved local and distant staging.
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Affiliation(s)
- Stephan H. Polanec
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Piotr Andrzejewski
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna, Vienna, Austria
| | - Pascal A. T. Baltzer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Thomas H. Helbich
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
| | - Alexander Stiglbauer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
| | - Dietmar Georg
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna, Vienna, Austria
| | - Georgios Karanikas
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Martin Susani
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Wadsak
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Markus Margreiter
- Department of Urology, Medical University of Vienna, Vienna, Austria
| | - Markus Mitterhauser
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Peter Brader
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
| | - Katja Pinker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
- * E-mail:
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Sekine T, de Galiza Barbosa F, Kuhn FP, Burger IA, Stolzmann P, Huber GF, Kollias SS, von Schulthess GK, Veit-Haibach P, Huellner MW. PET+MR versus PET/CT in the initial staging of head and neck cancer, using a trimodality PET/CT+MR system. Clin Imaging 2017; 42:232-239. [PMID: 28129606 DOI: 10.1016/j.clinimag.2017.01.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/19/2016] [Accepted: 01/10/2017] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the diagnostic accuracy of PET+MR with PET/CT in the initial staging of head and neck cancer. MATERIALS AND METHODS Contrast-enhanced PET/CT+MR was performed in 27 patients with newly diagnosed head and neck cancer. PET/CT and PET+MR were evaluated separately, and the TNM stage and factors influencing treatment were assessed. RESULTS The TNM staging by PET+MR was comparable to PET/CT (T: p=0.331, N: p=0.453, M: p=0.034). The sensitivity/specificity/accuracy of treatment-influencing factors by PET/CT and PET+MR were 0.68/0.99/0.97, and 1.00/1.00/0.99, respectively. CONCLUSIONS Whole-body staging with PET+MR yields at least equal diagnostic accuracy as PET/CT in head and neck cancer.
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Affiliation(s)
- Tetsuro Sekine
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland; Department of Radiology, Nippon Medical School, Tokyo, Japan.
| | | | - Felix P Kuhn
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland; Clinic of Neuroradiology, University Hospital Zurich, University of Zurich, Switzerland
| | - Irene A Burger
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland
| | - Paul Stolzmann
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland; Clinic of Neuroradiology, University Hospital Zurich, University of Zurich, Switzerland
| | - Gerhard F Huber
- Department of Otorhinolaryngology, University Hospital Zurich, University of Zurich, Switzerland
| | - Spyros S Kollias
- Clinic of Neuroradiology, University Hospital Zurich, University of Zurich, Switzerland
| | - Gustav K von Schulthess
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland
| | - Patrick Veit-Haibach
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland; Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland
| | - Martin W Huellner
- Department of Nuclear Medicine, University Hospital Zurich, University of Zurich, Switzerland
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Ratib O. A Perspective on the Impact of the Shine-Through Artifact in Clinical Applications of PET/MR Imaging. J Nucl Med 2015; 56:815-6. [PMID: 25858037 DOI: 10.2967/jnumed.115.155135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 11/16/2022] Open
Affiliation(s)
- Osman Ratib
- Division of Nuclear Medicine and Molecular Imaging, Department of Medical Imaging and Information Sciences, University Hospital of Geneva, Geneva, Switzerland
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Combined PET/MR: Where are we now? Summary report of the second international workshop on PET/MR imaging April 8-12, 2013, Tubingen, Germany. Mol Imaging Biol 2015; 16:295-310. [PMID: 24668195 DOI: 10.1007/s11307-014-0725-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This workshop was held a year after the initial positron emission tomography/magnetic resonance (PET/MR) workshop in Tübingen, which was recently reported in this journal. The discussions at the 2013 workshop, however, differed substantially from those of the initial workshop, attesting to the progress of combined PET/MR as an innovative imaging modality. Discussions were focused on the search for truly novel, unique clinical and research applications as well as technical issues such as reliable and accurate approaches for attenuation and scatter correction of PET emission data. The workshop provided hands-on experience with PET and MR imaging. In addition, structured and moderated open discussion sessions, including six dialogue boards and two roundtable discussions, provided input from current and future PET/MR imaging users. This summary provides a snapshot of the current achievements and challenges for PET/MR.
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Van Schouwenburg F, Ackermann C, Pitcher R. An audit of elective outpatient magnetic resonance imaging in a tertiary South African public-sector hospital. SA J Radiol 2014. [DOI: 10.4102/sajr.v18i1.689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background: Increasing demand for magnetic resonance imaging (MRI) has resulted in longer waiting times for elective MRI, particularly in resource-limited healthcare environments.However, inappropriate imaging requests may also contribute to prolonged MRI waiting times. At the time of the present study, the waiting time for elective MRI studies at Tygerberg Hospital (TBH), a tertiary-level public-sector healthcare facility in Cape Town (South Africa),was 24 weeks.Objectives: To document the nature and clinical appropriateness of scheduled TBH outpatient MRI examinations.Method: A retrospective analysis of the referral forms of all elective outpatient MRIexaminations scheduled at TBH from 01 June to 30 November 2011 was conducted. Patient age, gender, clinical details, provisional diagnosis, examination requested and referring clinician were recorded on a customised data sheet. Two radiologists independently evaluated the appropriateness of each request by comparing the clinical details and the provisional diagnosis provided with the 2012 American College of Radiology (ACR) guidelines for the appropriate use of MRI.Results: Four hundred and sixty-six patients (median age 42 years; interquartile range 19–55) who had 561 examinations were scheduled in the review period; 70 (15%) were children less than 6 years old. Neurosurgery (n = 164; 35%), orthopaedic (n = 144; 31%),neurology (n = 53; 11%) and paediatric (n = 27; 6%) outpatients accounted for the majority(81%) of referrals; 464 (99.6%) were from specialist clinics. MRIs of the spine (n = 314; 56%),brain (n = 152; 27%) and musculoskeletal system (n = 70, 13%) accounted for more than 95%of the investigations. In 455 cases (98%), the referral was congruent with published ACR guidelines for appropriate MRI utilisation.Conclusion: Scheduled outpatient MRI examinations at TBH reflect optimal clinical use of a limited resource. MRI utilisation is largely confined to traditional neuro-imaging. Any initiative to decrease the elective MRI waiting time should focus on service expansion.
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