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1.
J Nucl Med ; 59(6): 967-972, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29097408

RESUMO

Chronic sciatica is a major cause of disability worldwide, but accurate diagnosis of the causative pathology remains challenging. In this report, the feasibility of an 18F-FDG PET/MRI approach for improved diagnosis of chronic sciatica is presented. Methods:18F-FDG PET/MRI was performed on 9 chronic sciatica patients and 5 healthy volunteers (healthy controls). Region-of-interest analysis using SUVmax was performed, and 18F-FDG uptake in lesions was compared with that in the corresponding areas in healthy controls. Results: Significantly increased 18F-FDG uptake was observed in detected lesions in all patients and was correlated with pain symptoms. 18F-FDG-avid lesions not only were found in impinged spinal nerves but also were associated with nonspinal causes of pain, such as facet joint degeneration, pars defect, or presumed scar neuroma. Conclusion: The feasibility of 18F-FDG PET/MRI for diagnosing pain generators in chronic sciatica was demonstrated, revealing various possible etiologies.


Assuntos
Fluordesoxiglucose F18 , Imagem por Ressonância Magnética , Imagem Multimodal , Tomografia por Emissão de Pósitrons , Ciática/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Adulto , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor/complicações , Ciática/complicações , Adulto Jovem
2.
Theranostics ; 7(11): 2794-2805, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28824716

RESUMO

The ability to locate nerve injury and ensuing neuroinflammation would have tremendous clinical value for improving both the diagnosis and subsequent management of patients suffering from pain, weakness, and other neurologic phenomena associated with peripheral nerve injury. Although several non-invasive techniques exist for assessing the clinical manifestations and morphological aspects of nerve injury, they often fail to provide accurate diagnoses due to limited specificity and/or sensitivity. Herein, we describe a new imaging strategy for visualizing a molecular biomarker of nerve injury/neuroinflammation, i.e., the sigma-1 receptor (S1R), in a rat model of nerve injury and neuropathic pain. The two-fold higher increase of S1Rs was shown in the injured compared to the uninjured nerve by Western blotting analyses. With our novel S1R-selective radioligand, [18F]FTC-146 (6-(3-[18F]fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one), and positron emission tomography-magnetic resonance imaging (PET/MRI), we could accurately locate the site of nerve injury created in the rat model. We verified the accuracy of this technique by ex vivo autoradiography and immunostaining, which demonstrated a strong correlation between accumulation of [18F]FTC-146 and S1R staining. Finally, pain relief could also be achieved by blocking S1Rs in the neuroma with local administration of non-radioactive [19F]FTC-146. In summary, [18F]FTC-146 S1R PET/MR imaging has the potential to impact how we diagnose, manage and treat patients with nerve injury, and thus warrants further investigation.


Assuntos
Imagem por Ressonância Magnética/métodos , Neuralgia/diagnóstico por imagem , Neuralgia/patologia , Nervos Periféricos/diagnóstico por imagem , Nervos Periféricos/patologia , Tomografia por Emissão de Pósitrons/métodos , Receptores sigma/análise , Animais , Azepinas/administração & dosagem , Benzotiazóis/administração & dosagem , Modelos Animais de Doenças , Radioisótopos de Flúor/administração & dosagem , Marcação por Isótopo , Masculino , Neuroma/complicações , Ratos Sprague-Dawley
3.
J Nucl Med ; 58(12): 2004-2009, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28572487

RESUMO

The purpose of this study was to assess safety, biodistribution, and radiation dosimetry in humans for the highly selective σ-1 receptor PET agent 18F-6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one (18F-FTC-146). Methods: Ten healthy volunteers (5 women, 5 men; age ± SD, 34.3 ± 6.5 y) were recruited, and written informed consent was obtained from all participants. Series of whole-body PET/MRI examinations were acquired for up to 3 h after injection (357.2 ± 48.8 MBq). Blood samples were collected, and standard vital signs (heart rate, pulse oximetry, and body temperature) were monitored at regular intervals. Regions of interest were delineated, time-activity curves were calculated, and organ uptake and dosimetry were estimated. Results: All subjects tolerated the PET/MRI examination well, and no adverse reactions to 18F-FTC-146 were reported. High accumulation of 18F-FTC-146 was observed in σ-1 receptor-dense organs such as the pancreas and spleen, moderate uptake in the brain and myocardium, and low uptake in bone and muscle. High uptake was also observed in the kidneys and bladder, indicating renal tracer clearance. The effective dose of 18F-FTC-146 was 0.0259 ± 0.0034 mSv/MBq (range, 0.0215-0.0301 mSv/MBq). Conclusion: First-in-human studies with clinical-grade 18F-FTC-146 were successful. Injection of 18F-FTC-146 is safe, and absorbed doses are acceptable. The potential of 18F-FTC-146 as an imaging agent for a variety of neuroinflammatory diseases is currently under investigation.


Assuntos
Azepinas/farmacocinética , Benzotiazóis/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Adulto , Azepinas/efeitos adversos , Azepinas/síntese química , Benzotiazóis/efeitos adversos , Benzotiazóis/síntese química , Feminino , Voluntários Saudáveis , Humanos , Marcação por Isótopo , Imagem por Ressonância Magnética , Masculino , Imagem Multimodal , Radiometria , Compostos Radiofarmacêuticos/efeitos adversos , Compostos Radiofarmacêuticos/síntese química , Receptores sigma/efeitos dos fármacos , Receptores sigma/metabolismo , Distribuição Tecidual , Imagem Corporal Total
4.
Mol Imaging Biol ; 19(5): 779-786, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28280965

RESUMO

PURPOSE: Sigma-1 receptors (S1Rs) play an important role in many neurological disorders. Simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) with S1R radioligands may provide valuable information for diagnosing and guiding treatment for these diseases. Our previously reported S1R radioligand, [18F]FTC-146, demonstrated high affinity for the S1R (K i = 0.0025 nM) and excellent selectivity for the S1R over the sigma-2 receptor (S2Rs; K i = 364 nM) across several species (from mouse to non-human primate). Herein, we report the clinical-grade radiochemistry filed with exploratory Investigational New Drug (eIND) and first-in-human PET/MRI evaluation of [18F]FTC-146. PROCEDURES: [18F]FTC-146 is prepared via a direct [18F] fluoride nucleophilic radiolabeling reaction and formulated in 0.9 % NaCl containing no more than 10 % ethanol through sterile filtration. Quality control (QC) was performed based on USP 823 before doses were released for clinical use. The safety and whole body biodistribution of [18F]FTC-146 were evaluated using a simultaneous PET/MR scanner in two representative healthy human subjects. RESULTS: [18F]FTC-146 was synthesized with a radiochemical yield of 3.3 ± 0.7 % and specific radioactivity of 8.3 ± 3.3 Ci/µmol (n = 10, decay corrected to EOB). Both radiochemical and chemical purities were >95 %; the prepared doses were stable for 4 h at ambient temperature. All QC test results met specified clinical criteria. The in vivo PET/MRI investigations showed that [18F]FTC-146 rapidly crossed the blood brain barrier and accumulated in S1R-rich regions of the brain. There were also radioactivity distributed in the peripheral organs, i.e., the lungs, spleen, pancreas, and thyroid. Furthermore, insignificant uptake of [18F]FTC-146 was observed in cortical bone and muscle. CONCLUSION: A reliable and automated radiosynthesis for providing routine clinical-grade [18F]FTC-146 for human studies was established in a modified GE TRACERlab FXFN. PET/MRI demonstrated the initial tracer biodistribution in humans, and clinical studies investigating different S1R-related diseases are in progress.


Assuntos
Azepinas/química , Azepinas/síntese química , Benzotiazóis/química , Benzotiazóis/síntese química , Imagem por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Adulto , Azepinas/farmacocinética , Benzotiazóis/farmacocinética , Feminino , Humanos , Masculino , Distribuição Tecidual
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