Usefulness of Tc-99m Sestamibi studies for monitoring response to therapy in patients with high grade gliomas: a preliminary study

Congrès sous l’égide de la Société Française de Génie Biologique et Médical (SFGBM).National audienceEarly and late Sestamibi studies were acquired in addition to conventional MRI protocol in 14 patients with high-grade gliomas to monitor an antiangiogenic treatment. Global and local indices were deduced from these SPECT studies and were compared with progression free survival (PFS) and overall survival (OS). Variations of intensity in late studies were not correlated with PFS, but were related to OS. This suggests the possible role of Sestamibi for monitoring response to treatment

Relevance of Brain 18F-FDG PET Imaging in Probable Seronegative Encephalitis With Catatonia: A Case Report

Autoimmune encephalitis (AIE) is a rare, severe, and rapidly progressive encephalopathy, and its diagnosis is challenging, especially in adolescent populations when the presentation is mainly psychiatric. Currently, cerebral 18-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) imaging is not included in the diagnosis algorithm. We describe a 16-year-old patient with probable seronegative encephalitis with catatonia for which several cerebral PET scans were relevant and helpful for diagnosis, treatment decision making, and follow-up monitoring. The patient recovered after 2 years of treatment with etiologic treatment of AIE and treatment of catatonia. This case suggests a more systematic assessment of the clinical relevance of 18F-FDG-PET imaging in probable seronegative AIE

Imagerie isotopique des ganglions de la base (développements méthodologiques chez le primate et l homme)

Cette thèse porte sur la problématique propre au système des ganglions de la base et sur les pathologies du mouvement issues de leur dysfonctionnement dont la maladie de Parkinson. Elle se positionne à la jonction entre les connaissances nécessaires dans le domaine des neurosciences pour aborder ces problématiques et la maîtrise des outils d imagerie isotopique permettant d y répondre. Elle est l illustration de la diversité des approches neurochimiques et translationnelles que cette imagerie permet : grâce à un radioligand des récepteurs nicotiniques 4ß2 de l acétylcholine, le 2-[18F] fluoro-A-85830, la première étude de cette thèse a révélé une diminution de la densité de ces récepteurs dans le striatum et la substance noire de patients parkinsoniens. La seconde a montré qu il était possible d analyser à l échelle du voxel, les scintigraphies cérébrales de [123 I] FP-CIT même pathologiques, en procédant à une normalisation spatiale des images au moyen d un outil méthodologique adapté. Le dernier travail est une étude préclinique explorant les modifications du métabolisme cortical grâce au [18 F]-FDG, lors de dyskinésies provoquées par l injection d un antagoniste GABAergique dans le territoire sensorimoteur du pallidum externe : les premiers résultats montrent un profil métabolique cortical compatible avec la genèse de mouvements anormaux. Le point commun de ces études est la place centrale occupée par le développement méthodologique rendu possible par la maîtrise des outils et des concepts régissant l analyse complexe des images isotopiques et par la compréhension des concepts neuroscientifiques sous-jacents aux différentes études.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Mesure de la clairance pulmonaire du DTPA-TC99m (Aspects méthodologiques.Intérêt dans le suivi thérapeutique en oncologie hématologique)

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

PET Imaging in Neuro-Oncology: An Update and Overview of a Rapidly Growing Area

PET plays an increasingly important role in the management of brain tumors. This review outlines currently available PET radiotracers and their respective indications. It specifically focuses on 18F-FDG, amino acid and somatostatin receptor radiotracers, for imaging gliomas, meningiomas, primary central nervous system lymphomas as well as brain metastases. Recent advances in radiopharmaceuticals, image analyses and translational applications to therapy are also discussed. The objective of this review is to provide a comprehensive overview of PET imaging’s potential in neuro-oncology as an adjunct to brain MRI for all medical professionals implicated in brain tumor diagnosis and care

Increased 18F-FDG Uptake in Lhermitte-Duclos Disease With Cowden Syndrome Revealed by PET-MRI

International audienceA 62-year-old woman, with the history of breast and colorectal cancer, presented intermittent diplopia. A cerebellar lesion was revealed by F-FDG PET-MRI without post-gadolinium enhancement, but with increased perfusion and strong F-FDG uptake. The diagnosis of Cowden syndrome with PTEN gene mutation, linked to higher risk of neoplasia and occurrence of hamartomatous lesions characteristic of the Lhermitte-Duclos disease (LDD), was confirmed by genetic investigation

Visual interpretation of brain hypometabolism related to neurological long COVID: a French multicentric experience

International audienceBackground: This multicentre study aimed to provide a qualitative and consensual description of brain hypometabolism observed through the visual analysis of 18F-FDG PET images of patients with suspected neurological long COVID, regarding the previously reported long-COVID hypometabolic pattern involving hypometabolism in the olfactory bulbs and other limbic/paralimbic regions, as well as in the brainstem and cerebellum.Methods: From the beginning of August 2021 to the end of October 2021, the brain 18F-FDG PET scans of patients referred for suspected neurological long COVID with positive reverse transcription polymerase chain reaction (RT-PCR) and/or serology tests for SARS-CoV-2 infection were retrospectively reviewed in three French nuclear medicine departments (143 patients; 47.4 years old ± 13.6; 98 women). Experienced nuclear physicians from each department classified brain 18F-FDG PET scans according to the same visual interpretation analysis as being normal, mildly to moderately (or incompletely) affected, or otherwise severely affected within the previously reported long-COVID hypometabolic pattern.Results: On the 143 brain 18F-FDG PET scans performed during this 3-month period, 53% of the scans were visually interpreted as normal, 21% as mildly to moderately or incompletely affected, and 26% as severely affected according to the COVID hypometabolic pattern. On average, PET scans were performed at 10.9 months from symptom onset (± 4.8). Importantly, this specific hypometabolic pattern was similarly identified in the three nuclear medicine departments. Typical illustrative examples are provided to help nuclear physicians interpret long-COVID profiles.Conclusion: The proposed PET metabolic pattern is easily identified upon visual interpretation in clinical routine for approximately one half of patients with suspected neurological long COVID, requiring special consideration for frontobasal paramedian regions, the brainstem and the cerebellum, and certainly further adapted follow-up and medical care, while the second half of patients have normal brain PET metabolism on average 10.9 months from symptom onset

Relevance of Dynamic ¹⁸F-DOPA PET Radiomics for Differentiation of High-Grade Glioma Progression from Treatment-Related Changes

This study evaluates the relevance of 18F-DOPA PET static and dynamic radiomics for differentiation of high-grade glioma (HGG) progression from treatment-related changes (TRC) by comparing diagnostic performances to the current PET imaging standard of care. Eighty-five patients with histologically confirmed HGG and investigated by dynamic 18F-FDOPA PET in two institutions were retrospectively selected. ElasticNet logistic regression, Random Forest and XGBoost machine models were trained with different sets of features—radiomics extracted from static tumor-to-background-ratio (TBR) parametric images, radiomics extracted from time-to-peak (TTP) parametric images, as well as combination of both—in order to discriminate glioma progression from TRC at 6 months from the PET scan. Diagnostic performances of the models were compared to a logistic regression model with TBRmean ± clinical features used as reference. Training was performed on data from the first center, while external validation was performed on data from the second center. Best radiomics models showed only slightly better performances than the reference model (respective AUCs of 0.834 vs. 0.792, p < 0.001). Our current results show similar findings at the multicentric level using different machine learning models and report a marginal additional value for TBR static and TTP dynamic radiomics over the classical analysis based on TBR values

Functional brain connectome in posterior cortical atrophy

International audienceThis study investigated the functional brain connectome architecture in patients with Posterior Cortical Atrophy (PCA). Eighteen PCA patients and 29 age- and sex- matched healthy controls were consecutively recruited in a specialized referral center. Participants underwent neurologic examination, cerebrospinal fluid (CSF) examination for Alzheimer's disease (AD) biomarkers, cognitive assessment, and brain MRI. For a smaller subset of participants, FDG-PET examination was available. We assessed topological brain network properties and regional functional connectivity as well as intra- and inter-hemispheric connectivity, using graph analysis and connectomics. Supplementary analyses were performed to explore the association between the CSF AD profile and the connectome status, and taking into account hypometabolic, atrophic, and spared regions (nodes). PCA patients showed diffuse functional connectome alterations at both global and regional level, as well as a connectivity breakdown between the posterior brain nodes. They had a widespread loss of both intra- and inter-hemispheric connections, exceeding the structural damage, and including the frontal connections. In PCA, connectome alterations were identified in all the brain nodes irrespectively of their structural and metabolic classification and were associated with a connectivity breakdown between damaged and spared areas. Taken together, these findings suggest the potentially high sensitivity of graph-analysis and connectomic in capturing the progression and maybe early signs of neurodegeneration in PCA patients

Role of Positron Emission Tomography in Primary Central Nervous System Lymphoma

The incidence of primary central nervous system lymphoma has increased over the past two decades in immunocompetent patients and the prognosis remains poor. A diagnosis and complete evaluation of the patient is needed without delay, but histologic evaluation is not always available and PCNSL can mimic a variety of brain lesions on MRI. In this article, we review the potential role of 18F-FDG PET for the diagnosis of PCNSL in immunocompetent and immunocompromised patients. Its contribution to systemic assessment at the time of diagnosis has been well established by expert societies over the past decade. In addition, 18F-FDG provides valuable information for differential diagnosis and outcome prediction. The literature also shows the potential role of 18F-FDG as a therapeutic evaluation tool during the treatment and the end of the treatment. Finally, we present several new radiotracers that may have a potential role in the management of PCNSL in the future