Parametric response mapping of longitudinal PET scans and their use in detecting changes in Alzheimer’s diseases

Yoon

et al. 2015

Med. Phys.

Section: Introductionmentioning

confidence: 99%

Evaluation of a silicon photomultiplier PET insert for simultaneous PET and MR imaging

Yoon

et al. 2015

Med. Phys.

“…Spatial and temporal distributions of compounds labeled with a positron-emitting radionuclide are noninvasively measured by the PET scanner. Consequently, the PET scanner provides quantitative information about various physiologic and biochemical processes, such as glucose metabolism, gene expression, and drug occupancy (2)(3)(4)(5). Additionally, insufficient morphologic information in PET images can be compensated for by combining the PET scanner with morphologic imaging devices, such as CT and MRI.…”

mentioning

confidence: 99%

Simultaneous Multiparametric PET/MRI with Silicon Photomultiplier PET and Ultra-High-Field MRI for Small-Animal Imaging

Yoon

et al. 2016

J Nucl Med

Visualization of biologic processes at molecular and cellular levels has revolutionized the understanding and treatment of human diseases. However, no single biomedical imaging modality provides complete information, resulting in the emergence of multimodal approaches. Combining state-of-the-art PET and MRI technologies without loss of system performance and overall image quality can provide opportunities for new scientific and clinical innovations. Here, we present a multiparametric PET/MR imager based on a smallanimal dedicated, high-performance, silicon photomultiplier (SiPM) PET system and a 7-T MR scanner. Methods: A SiPM-based PET insert that has the peak sensitivity of 3.4% and center volumetric resolution of 1.92/0.53 mm 3 (filtered backprojection/ordered-subset expectation maximization) was developed. The SiPM PET insert was placed between the mouse body transceiver coil and gradient coil of a 7-T small-animal MRI scanner for simultaneous PET/MRI. Mutual interference between the MRI and SiPM PET systems was evaluated using various MR pulse sequences. A cylindric corn oil phantom was scanned to assess the effects of the SiPM PET on the MR image acquisition. To assess the influence of MRI on the PET imaging functions, several PET performance indicators including scintillation pulse shape, flood image quality, energy spectrum, counting rate, and phantom image quality were evaluated with and without the application of MR pulse sequences. Simultaneous mouse PET/MRI studies were also performed to demonstrate the potential and usefulness of the multiparametric PET/MRI in preclinical applications. Results: Excellent performance and stability of the PET system were demonstrated, and the PET/MRI combination did not result in significant image quality degradation of either modality. Finally, simultaneous PET/MRI studies in mice demonstrated the feasibility of the developed system for evaluating the biochemical and cellular changes in a brain tumor model and facilitating the development of new multimodal imaging probes. Conclusion: We developed a multiparametric imager with high physical performance and good system stability and demonstrated its feasibility for small-animal experiments, suggesting its usefulness for investigating in vivo molecular interactions of metabolites, and cross-validation studies of both PET and MRI.Key Words: PET/MRI; silicon photomultiplier (SiPM); hybrid imaging; multi-parametric imaging; dual-modality imaging probe Asubst antial role of small-animal imaging has been pinpointed in numerous studies in terms of understanding the underlying mechanism of human diseases and elucidating the efficacy of new therapeutic approaches. Among the in vivo small-animal imaging modalities, which are scaled down to dedicated devices from clinical ones, PET is the most-sensitive technique that is readily translatable to the clinic (1). Spatial and temporal distributions of compounds labeled with a positron-emitting radionuclide are noninvasively measured by the PET scanner. Consequently, the PET scanner p...

“…PET research has greatly contributed to advance our understanding of the brain in health and disease [4,[97][98][99][100][101][102] ; quantitative neuroreceptor mapping with kinetic modeling has played a key role in such contributions by offering accurate visualization and voxel-wise analysis of the distribution and activity of various neuroreceptors that are the most infl uential structures in the brain.…”

Section: Discussionmentioning

confidence: 99%

Recent advances in parametric neuroreceptor mapping with dynamic PET: basic concepts and graphical analyses

Seo¹,

Lee³

et al. 2014

Neurosci. Bull.

Tracer kinetic modeling in dynamic positron emission tomography (PET) has been widely used to investigate the characteristic distribution patterns or dysfunctions of neuroreceptors in brain diseases. Its practical goal has progressed from regional data quantification to parametric mapping that produces images of kinetic-model parameters by fully exploiting the spatiotemporal information in dynamic PET data. Graphical analysis (GA) is a major parametric mapping technique that is independent on any compartmental model configuration, robust to noise, and computationally efficient. In this paper, we provide an overview of recent advances in the parametric mapping of neuroreceptor binding based on GA methods. The associated basic concepts in tracer kinetic modeling are presented, including commonly-used compartment models and major parameters of interest. Technical details of GA approaches for reversible and irreversible radioligands are described, considering both plasma input and reference tissue input models. Their statistical properties are discussed in view of parametric imaging.