Applications for Preclinical PET/MRI

doi:10.1053/j.semnuclmed.2012.08.004

Seminars in Nuclear Medicine

Volume 43, Issue 1, January 2013, Pages 19-29

https://doi.org/10.1053/j.semnuclmed.2012.08.004 Get rights and content

Currently, the combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) as a hybrid imaging modality is receiving great attention not only in its emerging clinical applications but also in the preclinical field. Several prototypes based on several different types of PET detector technology have been developed in recent years, some of which have been used for first preclinical studies. This article provides an overview of currently available PET systems and considerations for combined PET/MRI workflows, and summarizes the results of the first studies performed on dedicated preclinical PET/MRI systems. The article also highlights other research using PET and MRI in combination and highlights potential benefits for integrated systems.

Section snippets

Combined PET and MRI—Available Technology

Combining PET and MRI together in one device that can obtain both images simultaneously requires significant modification of one or both systems owing to the inherent nature of the technology used, which is mutually interfering.1, 2, 3 The high magnetic field of the MRI makes the use of traditional and established photomultiplier tube–based PET detectors virtually impossible, and the MRI does not tolerate the insertion of magnetic or large metallic parts inside the field of view (FOV), as it

Preclinical PET/MRI and Image Registration—Why 1 + 1 May Not Equal 2

There is often the argument that, except for the limited number of cases where simultaneous acquisition of PET and MRI is absolutely necessary, PET and MRI scans on separate stand-alone systems may be used to achieve experimental goals by proper postprocessing of the data. However, there may be valuable gains from simultaneous PET/MRI even for the simple case of registering PET and MRI data that should not be underestimated. In the case of separately acquired data sets, sophisticated methods

Preclinical PET/MRI—New Methods for a New Modality

Although a lot of experience in the field of dual-modality imaging was gained from other hybrid systems like PET/CT,37, 38, 39 PET/MRI has some new features as well as limitations, which require new methods and workflows to be established. In sharp contrast with PET/CT, most PET/MRI systems have the ability to acquire PET and MRI data at the same time because both FOVs are physically overlaid. This allows for new approaches and new techniques for acquisition of data that can take advantage of

Preclinical PET/MRI Applications in Tumor Imaging

A problem that often occurs in tumor imaging is that the biodistribution of the tracer in a tumor mass is not always homogeneous, especially at later stages of tumor progression when necrosis may be present.55, 56, 57 Confirmation and more detailed information about the microenvironment of the tumor are often interesting and important and usually are obtained by terminal ex vivo histology at the end of the experiment. To allow multiple time points to be investigated in the same animal,

Preclinical PET/MRI for Cardiac Applications

Another potential field for application of combined PET/MRI systems is in cardiovascular research. Here, FDG PET may be used to assess the viability of the heart muscle, and ⁸²Rb PET can assess perfusion, whereas MRI can be used to accurately measure vital parameters such as stroke volume. Because the heart muscle is moving during the acquisition, this leads to blurring of the image data if the acquisition is not synchronized with the heartbeat of the subject. Incorporating information about

Preclinical PET/MRI for Neurological Applications

The highest expectations for the use of hybrid PET/MRI systems are probably for neurological applications, not only because of the exceptional contrast of MRI in the brain and because of MRI's ability to perform functional imaging in the brain (functional MRI) or to study connectivity using diffusion tensor imaging but also because PET has a wide range of applications (and accompanying radiotracers and radioligands) in the area of neurodegenerative diseases.69, 70, 71, 72, 73 Currently, in

Preclinical PET/MRI with a Clinical PET/MRI System

At the time of writing, preclinical simultaneous PET/MRI systems for small-animal imaging are only available at sites that have their own expert research groups working on developing the necessary PET detector technology and prototype systems. Thus, only a limited number of groups currently have access to this combined modality. However, there are many more research groups interested in using such technology for their own research. If collaboration with groups who can provide dedicated

Conclusions

The examples presented have shown that there is a broad range of applications for combined PET/MRI systems in the preclinical research field. A particular strength of combining PET and MRI in a single device is the good spatial coregistration that can be obtained as well as the ability to acquire data simultaneously. This not only can shorten examination times but also enables, for the first time, simultaneous measurement of dynamic processes and dual-modality assessment of the effect of

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Applications for Preclinical PET/MRI

Section snippets

Combined PET and MRI—Available Technology

Preclinical PET/MRI and Image Registration—Why 1 + 1 May Not Equal 2

Preclinical PET/MRI—New Methods for a New Modality

Preclinical PET/MRI Applications in Tumor Imaging

Preclinical PET/MRI for Cardiac Applications

Preclinical PET/MRI for Neurological Applications

Preclinical PET/MRI with a Clinical PET/MRI System

Conclusions

Curr Opin Neurobiol

J Magn Reson

J Neurosci Methods

Int J Radiat Oncol Biol Phys

Brain Cogn

Clin Radiol

Biomaterials

Blood

Eur J Cancer

Eur J Radiol

J Pharmacol Sci

Prog Neurobiol

Neuroimage

Neuroimage

Magn Reson Imaging

Neuropharmacology

Curr Opin Pharmacol

Neuroimage

A study of artefacts in simultaneous PET and MR imaging using a prototype MR compatible PET scanner

Phys Med Biol

Interference between PET and MRI sub-systems in a silicon-photomultiplier-based PET/MRI system

Phys Med Biol

Gamma shielding materials for MR-compatible PET

IEEE Trans Nucl Sci

Assessment of MR compatibility of a PET insert developed for simultaneous multiparametric PET/MR imaging on an animal system operating at 7 T

Magn Reson Med

PET and NMR dual acquisition (PANDA): Applications to isolated, perfused rat hearts

NMR Biomed

Development of a PET detector system compatible with MRI/NMR systems

IEEE Trans Nucl Sci

Simultaneous PET and MR imaging

Phys Med Biol

Simultaneous PET and NMR

Br J Radiol

Simultaneous MRI and PET imaging of a rat brain

Phys Med Biol

Simultaneous in vivo positron emission tomography and magnetic resonance imaging

Proc Natl Acad Sci U S A

Simultaneous PET-MRI: A new approach for functional and morphological imaging

Nat Med

Initial results of simultaneous PET/MRI experiments with an MRI-compatible silicon photomultiplier PET scanner

J Nucl Med

Simultaneous imaging using Si-PM-based PET and MRI for development of an integrated PET/MRI system

Phys Med Biol

Small animal simultaneous PET/MRI: Initial experiences in a 9.4 T microMRI

Phys Med Biol

Simultaneous PET/MR body imaging in rats: Initial experiences with an integrated PET/MRI scanner

Ann Nucl Med

Design and performance from an integrated PET/MRI system for small animals

Ann Nucl Med

First images from the BNL simultaneous PET/MRI scanner

J Nucl Med

Development of a combined micro-PET-MR system

IEEE Nucl Sci Symp Conf Rec

Performance evaluation of the 16-module quad-HIDAC small animal PET camera

Phys Med Biol

MicroPET II: Design, development and initial performance of an improved microPET scanner for small-animal imaging

Phys Med Biol

National Electrical Manufacturers Association NU-4 performance evaluation of the PET component of the NanoPET/CT preclinical PET/CT scanner

J Nucl Med

Performance evaluation of the inveon dedicated PET preclinical tomograph based on the NEMA NU-4 standards

J Nucl Med

Effect of resolution improvement on required count density in ECT imaging: A computer simulation

Phys Med Biol

Pharmacological constraints associated with positron emission tomographic scanning of small laboratory animals

Eur J Nucl Med

Accuracy of 3D volumetric image registration based on CT, MR and PET/CT phantom experiments

J Appl Clin Med Phys

Multi-modality medical image registration using support vector machines

Conf Proc IEEE Eng Med Biol Soc