Simultaneous MRI and PET imaging of a rat brain

Raylman, Raymond R.; Majewski, S.; Lemieux, Susan K.; Velan, S. Sendhil; Kross, B.; Popov, V.; Smith, Mark F.; Weisenberger, A.G.; Zorn, C.; Marano, Gary

doi:10.1088/0031-9155/51/24/006

Cited by 118 publications

(86 citation statements)

References 19 publications

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“…Preclinical PET/MR imaging hardware for small-animal studies has advanced (2)(3)(4)12,22,(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40). Although most preclinical PET/MR imaging systems are designed for imaging mice, there is significant interest in cardiac research using rats, especially the spontaneously hypertensive rat model of hypertensive left ventricle hypertrophy.…”

Section: Cardiac Pet/mr Imaging Current State Of Cardiac Pet/mr Imagingmentioning

confidence: 99%

Preclinical and Translational PET/MR Imaging

et al. 2014

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Combined PET and MR imaging (PET/MR imaging) has progressed tremendously in recent years. The focus of current research has shifted from technologic challenges to the application of this new multimodal imaging technology in the areas of oncology, cardiology, neurology, and infectious diseases. This article reviews studies in preclinical and clinical translation. The common theme of these initial results is the complementary nature of combined PET/MR imaging that often provides additional insights into biologic systems that were not clearly feasible with just one modality alone. However, in vivo findings require ex vivo validation. Combined PET/MR imaging also triggers a multitude of new developments in image analysis that are aimed at merging and using multimodal information that ranges from better tumor characterization to analysis of metabolic brain networks. The combination of connectomics information that maps brain networks derived from multiparametric MR data with metabolic information from PET can even lead to the formation of a new research field that we would call cometomics that would map functional and metabolic brain networks. These new methodologic developments also call for more multidisciplinarity in the field of molecular imaging, in which close interaction and training among clinicians and a variety of scientists is needed. Mol ecular imaging of small animals for biomedical research is an emerging field (1). It penetrates successfully into areas that are historically dominated by ex vivo molecular biology methods and therefore bears an enormous potential. Exploiting the full range of options of noninvasive visualization and quantification of metabolism, disease-specific dysfunction, therapy response, and cell trafficking requires that specific biomarkers yield information about molecular and functional processes as well as morphologic details. Single-modality imaging, such as stand-alone PET, SPECT, MR imaging, CT, or ultrasound, is often unable to provide the desired comprehensive information. Dedicated small-animal PET/CT and SPECT/CT scanners have been well received in the biomedical imaging sciences and have set the stage for a new combined imaging modality, PET/MR imaging, which has been introduced and successfully applied in biomedical studies (2,3). PET and MR imaging are both distinct modalities offering great versatility for advanced imaging applications in various fields of biomedicine. The combination of these two modalities into a single device merges functional and morphologic information from MR imaging with molecular PET data. The strength of PET lies in its high detection sensitivity and accurate quantification, but PET lacks good spatial resolution and tissue contrast. MR imaging, however, enables highresolution imaging of morphology with good soft-tissue contrast, detects endogenous metabolite distributions using spectroscopy, and allows dynamic acquisition of tissue perfusion and additional functional parameters (4).Thus, PET/MR imaging paves the way for noninvasive imaging to...

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Section: Cardiac Pet/mr Imaging Current State Of Cardiac Pet/mr Imagingmentioning

confidence: 99%

Preclinical and Translational PET/MR Imaging

et al. 2014

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“…This PET insert, however, is still limited to producing a single transverse slice through the object. PMT-based approaches using long optical fibers have also been used to obtain limited angle tomographic PET images simultaneously with MRI in vivo [22].…”

Section: Pmt-based Pet Systems Inside Existing Mri Scannersmentioning

confidence: 99%

“…In Fig. 15, the top row shows data from cells incubated with mal-BSA(Gd-DOTA) 22 , the middle row contains BSA ðGd-DOTAÞ 22 , and the bottom row is a pure water control. As evident in the figure, there is no uptake of the labeled BSA probe, while there is increasing signal intensity with increasing concentrations of the mal-BSA agent as expected.…”

Section: ) Targeting Of Mal-bsa Probe To Macrophages In Vitromentioning

confidence: 99%

The Integration of Positron Emission Tomography With Magnetic Resonance Imaging

Cherry¹,

Louie

Jacobs

2008

Proc. IEEE

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| A number of laboratories and companies are currently exploring the development of integrated imaging systems for magnetic resonance imaging (MRI) and positron emission tomography (PET). Scanners for both preclinical and human research applications are being pursued. In contrast to the widely distributed and now quite mature PET/computed tomography technology, most PET/MRI designs allow for simultaneous rather than sequential acquisition of PET and MRI data. While this offers the possibility of novel imaging strategies, it also creates considerable challenges for acquiring artifact-free images from both modalities. This paper discusses the motivation for developing combined PET/MRI technology, outlines the obstacles in realizing such an integrated instrument, and presents recent progress in the development of both the instrumentation and of novel imaging agents for combined PET/MRI studies. The performance of the first-generation PET/MRI systems is described. Finally, a range of possible biomedical applications for PET/MRI are outlined.

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“…There are currently several research groups worldwide working on the problem of developing combined positron emission tomography (PET) and MRI scanners (1)(2)(3)(4)(5)(6)(7)(8). The motivation for this development has been the potential for combining, both temporally and spatially, the highly specific functional information available from PET with the versatile soft tissue structural image data available from MRI.…”

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confidence: 99%

“…Systems with PMT-based light-detection schemes typically employ long optical fibers to guide light from the scintillation crystals to the magnetically sensitive PMTs, which are located in the fringe field of the magnet (2,6,20). Although PMTs have low noise and good efficiency, limited coupling between the scintillator and optical fiber decreases the amount of detected scintillation light and degrades the energy and timing resolution.…”

mentioning

confidence: 99%

Evaluation of a positron emission tomography (PET)‐compatible field‐cycled MRI (FCMRI) scanner

Gilbert

Scholl

Handler

et al. 2009

Magnetic Resonance in Med

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Field-cycled MRI (FCMRI) uses two independent, actively controlled resistive magnets to polarize a sample and to provide the magnetic field environment during data acquisition. This separation of tasks allows for novel forms of contrast, reduction of susceptibility artifacts, and a versatility in design that facilitates the integration of a second imaging modality. A 0.3T/4-MHz FC-MRI scanner was constructed with a 9-cm-wide opening through the side for the inclusion of a photomultiplier-tube-based positron emission tomography (PET) system. The performance of the FC-MRI scanner was evaluated prior to integrating PET detectors. Quantitative measurements of the system's signal, phase, and temperature were recorded. The polarizing and readout magnets could be operated continuously at 100 A without risk of damage to the system. Transient instabilities in the readout magnet, caused by the pulsing of the polarizing magnet, dissipated in 50 ms; this resulted in a steady-state homogeneity of 32 Hz over a 7-cmdiameter volume. There are currently several research groups worldwide working on the problem of developing combined positron emission tomography (PET) and MRI scanners (1-8). The motivation for this development has been the potential for combining, both temporally and spatially, the highly specific functional information available from PET with the versatile soft tissue structural image data available from MRI. The fact that MRI functions without the use of additional ionizing radiation, as compared to X-ray computedtomography systems, is also of significant importance in longitudinal high-resolution small-animal studies. Although every combined system inevitably involves modification of both PET and MRI systems in some way, it is helpful to identify two extremes of approach: those that seek to alter PET system architecture to make it compatible with conventional MRI systems, and those that seek to alter MRI system architecture to make it compatible with conventional PET systems. The most common has been to alter PET system design, most significantly by replacing the magnetically sensitive photomultiplier tube (PMT) with an avalanche photodiode (APD) as the light-detection system (1,9). The basic idea is to construct an APD-based PET insert system more or less permanently within the bore of the MRI system. To the extent to which the PET detectors and data transfer lines are not affected by the operation of the gradient and radio frequency (RF) systems, PET and MRI data can be acquired simultaneously using this approach. Because APD detectors are relatively new technology and have not seen widespread use in PET systems, the sensitivity of PET in combined PET/MRI systems has been quite low compared to that achieved in traditional PET systems. This is not a fundamental limitation of APD detector technology, but it is at present a reality that reduces the effectiveness of the PET/MRI system combination. This manuscript presents the evaluation of a field-cycled MRI (FCMRI) scanner that was designed for the integration o...

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Simultaneous MRI and PET imaging of a rat brain

Cited by 118 publications

References 19 publications

Preclinical and Translational PET/MR Imaging

Preclinical and Translational PET/MR Imaging

The Integration of Positron Emission Tomography With Magnetic Resonance Imaging

Evaluation of a positron emission tomography (PET)‐compatible field‐cycled MRI (FCMRI) scanner

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