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Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain.

ABSTRACT: The partial pressure in oxygen remains challenging to map in the brain. Two main strategies exist to obtain surrogate measures of tissue oxygenation: the tissue saturation studied by magnetic resonance imaging (S_tO₂-MRI) and the identification of hypoxia by a positron emission tomography (PET) biomarker with 3-[¹⁸F]fluoro-1-(2-nitro-1-imidazolyl)-2-propanol ([¹⁸F]-FMISO) as the leading radiopharmaceutical. Nonetheless, a formal validation of S_tO₂-MRI against FMISO-PET has not been performed. The objective of our studies was to compare the two approaches in (a) the normal rat brain when the rats were submitted to hypoxemia; (b) animals implanted with four tumour types differentiated by their oxygenation. Rats were submitted to normoxic and hypoxemic conditions. For the brain tumour experiments, U87-MG, U251-MG, 9L and C6 glioma cells were orthotopically inoculated in rats. For both experiments, S_tO₂-MRI and [¹⁸F]-FMISO PET were performed sequentially. Under hypoxemia conditions, S_tO₂-MRI revealed a decrease in oxygen saturation in the brain. Nonetheless, [¹⁸F]-FMISO PET, pimonidazole immunohistochemistry and molecular biology were insensitive to hypoxia. Within the context of tumours, S_tO₂-MRI was able to detect hypoxia in the hypoxic models, mimicking [¹⁸F]-FMISO PET with high sensitivity/specificity. Altogether, our data clearly support that, in brain pathologies, S_tO₂-MRI could be a robust and specific imaging biomarker to assess hypoxia.

SUBMITTER: Valable S

PROVIDER: S-EPMC5531354 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

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Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain.

Valable Samuel S Corroyer-Dulmont Aurélien A Chakhoyan Ararat A Durand Lucile L Toutain Jérôme J Divoux Didier D Barré Louisa L MacKenzie Eric T ET Petit Edwige E Bernaudin Myriam M Touzani Omar O Barbier Emmanuel L EL

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20160101 7

The partial pressure in oxygen remains challenging to map in the brain. Two main strategies exist to obtain surrogate measures of tissue oxygenation: the tissue saturation studied by magnetic resonance imaging (StO2-MRI) and the identification of hypoxia by a positron emission tomography (PET) biomarker with 3-[18F]fluoro-1-(2-nitro-1-imidazolyl)-2-propanol ([18F]-FMISO) as the leading radiopharmaceutical. Nonetheless, a formal validation of St</s ...[more]

PMID: 27702880

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Project description:ImportanceMyocardial replacement fibrosis has been reported to occur in one-third of patients with mitral valve prolapse (MVP) and significant mitral regurgitation (MR). However, it remains unknown whether there are detectable changes in myocardial metabolism suggestive of inflammation or ischemia that accompany the development of fibrosis.ObjectivesTo characterize the burden and distribution of fluorine 18-labeled (18F) fluorodeoxyglucose (FDG) uptake and late gadolinium enhancement (LGE) in patients with degenerative MVP and ventricular ectopy.Design, setting, and participantsProspective observational study of 20 patients with MVP and significant primary degenerative MR who were referred for mitral valve repair and underwent hybrid positron emission tomography/magnetic resonance imaging (PET/MRI). Ventricular arrhythmias were categorized as either complex (n = 12) or minor (n = 8). Coregistered hybrid 18F FDG-PET and MRI LGE images were assessed and categorized. Recruitment occurred in the new patient clinic of a mitral valve repair reference center. This study was conducted from January 11, 2018, to June 26, 2019.ExposuresSimultaneous cardiac 18F FDG-PET and MRI with LGE imaging on a hybrid PET/MRI system and ambulatory rhythm monitoring.Main outcomes and measuresPatients were categorized by the presence and pattern of FDG uptake and LGE, the severity of ventricular arrhythmias, and the indication for mitral valve surgery.ResultsIn the cohort of 20 patients, the median age was 59.5 years (interquartile range, 52.5-63.2 years). Focal, or focal-on-diffuse uptake, of 18F-FDG (PET positive) was detected in 17 of 20 patients (85%). The FDG uptake coexisted with areas of LGE (PET/MRI positive) in 14 patients (70%). Of the 5 asymptomatic patients with normal ventricular indices and absence of any surgical indications, all were PET/MRI positive.Conclusions and relevanceIn this pilot study, we demonstrate a novel association between degenerative MVP and FDG uptake, a surrogate for myocardial inflammation and/or ischemia. Such evidence of myocardial injury, even in asymptomatic patients, suggests an ongoing subclinical disease process. These findings warrant further investigation into whether imaging for myocardial inflammation, ischemia, and scar has a role in arrhythmic risk stratification and whether it provides incremental prognostic value in patients with chronic severe mitral regurgitation undergoing active surveillance.

Dataset Information

Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain.

Publications

Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain.

Similar Datasets

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