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Calcagno C, Pérez-Medina C, Mulder WJM, Fayad ZA. Whole-Body Atherosclerosis Imaging by Positron Emission Tomography/Magnetic Resonance Imaging: From Mice to Nonhuman Primates. Arterioscler Thromb Vasc Biol 2020; 40:1123-1134. [PMID: 32237905 DOI: 10.1161/atvbaha.119.313629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiovascular disease due to atherosclerosis is still the main cause of morbidity and mortality worldwide. This disease is a complex systemic disorder arising from a network of pathological processes within the arterial vessel wall, and, outside of the vasculature, in the hematopoietic system and organs involved in metabolism. Recent years have seen tremendous efforts in the development and validation of quantitative imaging technologies for the noninvasive evaluation of patients with atherosclerotic cardiovascular disease. Specifically, the advent of combined positron emission tomography and magnetic resonance imaging scanners has opened new exciting opportunities in cardiovascular imaging. In this review, we will describe how combined positron emission tomography/magnetic resonance imaging scanners can be leveraged to evaluate atherosclerotic cardiovascular disease at the whole-body level, with specific focus on preclinical animal models of disease, from mouse to nonhuman primates. We will broadly describe 3 major areas of application: (1) vascular imaging, for advanced atherosclerotic plaque phenotyping and evaluation of novel imaging tracers or therapeutic interventions; (2) assessment of the ischemic heart and brain; and (3) whole-body imaging of the hematopoietic system. Finally, we will provide insights on potential novel technical developments which may further increase the relevance of integrated positron emission tomography/magnetic resonance imaging in preclinical atherosclerosis studies.
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Affiliation(s)
- Claudia Calcagno
- From the BioMedical Engineering and Imaging Institute (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Department of Radiology (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY
| | - Carlos Pérez-Medina
- From the BioMedical Engineering and Imaging Institute (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Department of Radiology (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (C.P.-M.)
| | - Willem J M Mulder
- From the BioMedical Engineering and Imaging Institute (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Department of Radiology (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Department of Oncological Sciences (W.J.M.M.), Icahn School of Medicine at Mount Sinai, NY.,Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, the Netherlands (W.J.M.M.)
| | - Zahi A Fayad
- From the BioMedical Engineering and Imaging Institute (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY.,Department of Radiology (C.C., C.P.-M., W.J.M.M., Z.A.F.), Icahn School of Medicine at Mount Sinai, NY
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Selfridge AR, Cherry SR, Judenhofer MS. Optimization of a depth of interaction encoding PET block detector for a PET/MRI insert. Phys Med Biol 2018; 63:235031. [PMID: 30520420 DOI: 10.1088/1361-6560/aaef59] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Preclinical positron emission tomography, combined with magnetic resonance imaging (PET/MRI), is increasingly used as a tool to simultaneously characterize functional processes in vivo. Many emerging preclinical applications, however, are limited by PET detection sensitivity, especially when generating short imaging frames for quantitative studies. One such application is dynamic multifunctional imaging, which probes multiple aspects of a biological process, using relationships between the datasets to quantify interactions. These studies have limited accuracy due to the relatively low sensitivity of modern preclinical PET/MRI systems. The goal of this project is to develop a preclinical PET/MRI insert with detection sensitivity above 15% (250-750 keV) to improve quantitation in dynamic PET imaging. To achieve this sensitivity, we have developed a detector module incorporating a 2 cm thick crystal block, which will be arranged into a system with 8 cm axial FOV, targeting mice and rats. To maintain homogenous spatial resolution, the detector will incorporate dual-ended depth-of-interaction (DOI) encoding with silicon photomultiplier (SiPM) based photodetector arrays. The specific aim of this work is to identify a detector configuration with adequate performance for the proposed system. We have optimized the SiPM array geometry and tested two crystal array materials with pitch ranging from 0.8 to 1.2 mm and various surface treatments and reflectors. From these configurations, we have identified the best balance between crystal separation, energy resolution, and DOI resolution. The final detector module uses two rectangular SiPM arrays with 5 × 6 and 5 × 4 elements. The photodetector arrays are coupled to a 19 × 19 array of 1 mm pitch LYSO crystals with polished surfaces and a diffuse reflector. The prototype design has 14.3% ± 2.9% energy resolution, 3.57 ± 0.88 mm DOI resolution, and resolves all elements in the crystal array, giving it sufficient performance to serve as the basis for the proposed high sensitivity PET/MRI insert.
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Affiliation(s)
- Aaron R Selfridge
- Department of Biomedical Engineering, UC Davis, Davis, California, United States of America. Author to whom any correspondence should be addressed
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