Positron emission tomography imaging in evaluation of MS pathology in vivo

2018 ◽  
Vol 24 (11) ◽  
pp. 1399-1412 ◽  
Author(s):  
Heidi Högel ◽  
Eero Rissanen ◽  
Anna Vuorimaa ◽  
Laura Airas
Keyword(s):  
Positron Emission Tomography ◽  
Pet Imaging ◽  
Human Subjects ◽  
Positron Emission Tomography Imaging ◽  
Translocator Protein ◽  
Emission Tomography ◽  
Amyloid Pet ◽  
Positron Emission ◽  
Density Evaluation

Positron emission tomography (PET) gives an opportunity to quantitate the expression of specific molecular targets in vivo and longitudinally in brain and thus enhances our possibilities to understand and follow up multiple sclerosis (MS)-related pathology. For successful PET imaging, one needs a relevant target molecule within the brain, to which a blood–brain barrier–penetrating specific radioligand will bind. 18-kDa translocator protein (TSPO)-binding radioligands have been used to detect activated microglial cells at different stages of MS, and remyelination has been measured using amyloid PET. Several PET ligands for the detection of other inflammatory targets, besides TSPO, have been developed but not yet been used for imaging MS patients. Finally, synaptic density evaluation has been successfully tested in human subjects and gives opportunities for the evaluation of the development of cortical and deep gray matter pathology in MS. This review will discuss PET imaging modalities relevant for MS today.

scholarly journals Development of a blood sample detector for multi-tracer positron emission tomography using gamma spectroscopy

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Carlos Velasco ◽  
Adriana Mota-Cobián ◽  
Jesús Mateo ◽  
Samuel España
Keyword(s):  
Positron Emission Tomography ◽  
Blood Sample ◽  
Pet Imaging ◽  
Spectroscopic Analysis ◽  
Gamma Spectroscopy ◽  
Emission Tomography ◽  
Blood Samples ◽  
Positron Emission

Abstract Background Multi-tracer positron emission tomography (PET) imaging can be accomplished by applying multi-tracer compartment modeling. Recently, a method has been proposed in which the arterial input functions (AIFs) of the multi-tracer PET scan are explicitly derived. For that purpose, a gamma spectroscopic analysis is performed on blood samples manually withdrawn from the patient when at least one of the co-injected tracers is based on a non-pure positron emitter. Alternatively, these blood samples required for the spectroscopic analysis may be obtained and analyzed on site by an automated detection device, thus minimizing analysis time and radiation exposure of the operating personnel. In this work, a new automated blood sample detector based on silicon photomultipliers (SiPMs) for single- and multi-tracer PET imaging is presented, characterized, and tested in vitro and in vivo. Results The detector presented in this work stores and analyzes on-the-fly single and coincidence detected events. A sensitivity of 22.6 cps/(kBq/mL) and 1.7 cps/(kBq/mL) was obtained for single and coincidence events respectively. An energy resolution of 35% full-width-half-maximum (FWHM) at 511 keV and a minimum detectable activity of 0.30 ± 0.08 kBq/mL in single mode were obtained. The in vivo AIFs obtained with the detector show an excellent Pearson’s correlation (r = 0.996, p < 0.0001) with the ones obtained from well counter analysis of discrete blood samples. Moreover, in vitro experiments demonstrate the capability of the detector to apply the gamma spectroscopic analysis on a mixture of 68Ga and 18F and separate the individual signal emitted from each one. Conclusions Characterization and in vivo evaluation under realistic experimental conditions showed that the detector proposed in this work offers excellent sensibility and stability. The device also showed to successfully separate individual signals emitted from a mixture of radioisotopes. Therefore, the blood sample detector presented in this study allows fully automatic AIFs measurements during single- and multi-tracer PET studies.

scholarly journals Development of 2-Deoxy-2-[18F]fluororibose for Positron Emission Tomography Imaging Liver Function in Vivo

2015 ◽  
Vol 58 (14) ◽  
pp. 5538-5547 ◽  
Author(s):  
Nikolai M. Evdokimov ◽  
Peter M. Clark ◽  
Graciela Flores ◽  
Timothy Chai ◽  
Kym F. Faull ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Liver Function ◽  
Positron Emission Tomography Imaging ◽  
Emission Tomography ◽  
Tomography Imaging ◽  
Positron Emission

scholarly journals A Review of Diagnostic Impact of Amyloid Positron Emission Tomography Imaging in Clinical Practice

2018 ◽  
Vol 46 (3-4) ◽  
pp. 154-167 ◽  
Author(s):  
Yejin Kim ◽  
Paul Rosenberg ◽  
Esther Oh
Keyword(s):  
Positron Emission Tomography ◽  
Clinical Practice ◽  
Pet Imaging ◽  
Clinical Utility ◽  
Patient Management ◽  
Emission Tomography ◽  
Amyloid Pet ◽  
Diagnostic Confidence ◽  
Positron Emission ◽  
Amyloid Pet Imaging

Background: Molecular imaging of brain amyloid for the diagnosis of Alzheimer’s disease (AD) using positron emission tomography (PET) has been approved for use in clinical practice by the Food and Drug Administration (FDA) since 2012. However, the clinical utility and diagnostic impact of amyloid PET imaging remain controversial. We conducted a review of the recent studies investigating clinical utility of amyloid PET imaging with focus on changes in diagnosis, diagnostic confidence, and patient management. Summary: A total of 16 studies were included in the final analysis. Overall rate of changes in diagnosis after amyloid PET ranged from 9 to 68% (pooled estimate of 31%, 95% CI 23–39%). All studies reported overall increase in diagnostic confidence or diagnostic certainty after amyloid PET. Changes in patient management ranged from 37 to 87%; the most common type of change in management reported was either the initiation or discontinuation of planned AD medications. Key Messages: Amyloid PET imaging led to moderate to significant changes in diagnosis, diagnostic confidence, and subsequent patient management. It may be most useful in patients with high level of diagnostic uncertainty even after the completing the standard workup.

scholarly journals Imaging Cardiovascular and Lung Macrophages With the Positron Emission Tomography Sensor 64 Cu-Macrin in Mice, Rabbits, and Pigs

2020 ◽  
Vol 13 (10) ◽  
Author(s):  
Matthias Nahrendorf ◽  
Friedrich Felix Hoyer ◽  
Anu E. Meerwaldt ◽  
Mandy M.T. van Leent ◽  
Max L. Senders ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Flow Cytometry ◽  
Confocal Microscopy ◽  
Pet Imaging ◽  
Near Infrared ◽  
Emission Tomography ◽  
Imaging Biomarker ◽  
Positron Emission ◽  
Pulmonary Macrophages

Background: Macrophages, innate immune cells that reside in all organs, defend the host against infection and injury. In the heart and vasculature, inflammatory macrophages also enhance tissue damage and propel cardiovascular diseases. Methods: We here use in vivo positron emission tomography (PET) imaging, flow cytometry, and confocal microscopy to evaluate quantitative noninvasive assessment of cardiac, arterial, and pulmonary macrophages using the nanotracer 64 Cu-Macrin—a 20-nm spherical dextran nanoparticle assembled from nontoxic polyglucose. Results: PET imaging using 64 Cu-Macrin faithfully reported accumulation of macrophages in the heart and lung of mice with myocardial infarction, sepsis, or pneumonia. Flow cytometry and confocal microscopy detected the near-infrared fluorescent version of the nanoparticle ( VT680 Macrin) primarily in tissue macrophages. In 5-day-old mice, 64 Cu-Macrin PET imaging quantified physiologically more numerous cardiac macrophages. Upon intravenous administration of 64 Cu-Macrin in rabbits and pigs, we detected heightened macrophage numbers in the infarcted myocardium, inflamed lung regions, and atherosclerotic plaques using a clinical PET/magnetic resonance imaging scanner. Toxicity studies in rats and human dosimetry estimates suggest that 64 Cu-Macrin is safe for use in humans. Conclusions: Taken together, these results indicate 64 Cu-Macrin could serve as a facile PET nanotracer to survey spatiotemporal macrophage dynamics during various physiological and pathological conditions. 64 Cu-Macrin PET imaging could stage inflammatory cardiovascular disease activity, assist disease management, and serve as an imaging biomarker for emerging macrophage-targeted therapeutics.

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