Borderline Findings in -(2-[F]-Fluoroethyl)-l-Tyrosine PET of Patients with Suspected Glioma Relapse: Role in Clinical Practice.

One of the most common clinical indications for amino acid PET using the tracer -(2-[F]-fluoroethyl)-l-tyrosine (F-FET) is the differentiation of tumor relapse from treatment-related changes in patients with gliomas. A subset of patients may present with an uptake of F-FET close to recommended threshold values. The goal of this study was to investigate the frequency of borderline cases and the role of quantitative F-FET PET parameters in this situation.

Glutamate Signaling in Patients With Parkinson Disease With REM Sleep Behavior Disorder.

Background And Objectives: Clinical heterogeneity of patients with Parkinson disease (PD) is well recognized. PD with REM sleep behavior disorder (RBD) is a more malignant phenotype with faster motor progression and higher nonmotor symptom burden. However, the neural mechanisms underlying this clinical divergence concerning imbalances in neurotransmitter systems remain elusive.

Structural connectome-based predictive modeling of cognitive deficits in treated glioma patients.

Background: In glioma patients, tumor growth and subsequent treatments are associated with various types of brain lesions. We hypothesized that cognitive functioning in these patients critically depends on the maintained structural connectivity of multiple brain networks.

Methods: The study included 121 glioma patients (median age, 52 years; median Eastern Cooperative Oncology Group performance score 1; CNS-WHO Grade 3 or 4) after multimodal therapy.

Assessment of Brain Tumour Perfusion Using Early-Phase F-FET PET: Comparison with Perfusion-Weighted MRI.

Purpose: Morphological imaging using MRI is essential for brain tumour diagnostics. Dynamic susceptibility contrast (DSC) perfusion-weighted MRI (PWI), as well as amino acid PET, may provide additional information in ambiguous cases. Since PWI is often unavailable in patients referred for amino acid PET, we explored whether maps of relative cerebral blood volume (rCBV) in brain tumours can be extracted from the early phase of PET using O-(2-F-fluoroethyl)-L-tyrosine (F-FET).

Hybrid PET/MRI in Cerebral Glioma: Current Status and Perspectives.

Advanced MRI methods and PET using radiolabelled amino acids provide valuable information, in addition to conventional MR imaging, for brain tumour diagnostics. These methods are particularly helpful in challenging situations such as the differentiation of malignant processes from benign lesions, the identification of non-enhancing glioma subregions, the differentiation of tumour progression from treatment-related changes, and the early assessment of responses to anticancer therapy. The debate over which of the methods is preferable in which situation is ongoing, and has been addressed in numerous studies.

The impact of brain lesions on health-related quality of life in patients with WHO CNS grade 3 or 4 glioma: a lesion-function and resting-state fMRI analysis.

Purpose: In glioma patients, tumor development and multimodality therapy are associated with changes in health-related quality of life (HRQoL). It is largely unknown how different types and locations of tumor- and treatment-related brain lesions, as well as their relationship to white matter tracts and functional brain networks, affect HRQoL.

Methods: In 121 patients with pretreated gliomas of WHO CNS grades 3 or 4, structural MRI, O-(2-[F]fluoroethyl)-L-tyrosine (FET) PET, resting-state functional MRI (rs-fMRI) and self-reported HRQoL questionnaires (EORTC QLQ-C30/BN20) were obtained.

Clinical applications and prospects of PET imaging in patients with IDH-mutant gliomas.

PET imaging using radiolabeled amino acids in addition to MRI has become a valuable diagnostic tool in the clinical management of patients with brain tumors. This review provides a comprehensive overview of PET studies in glioma patients with a mutation in the isocitrate dehydrogenase gene (IDH). A considerable fraction of these tumors typically show no contrast enhancement on MRI, especially when classified as grade 2 according to the World Health Organization classification of Central Nervous System tumors.

Alterations in white matter fiber density associated with structural MRI and metabolic PET lesions following multimodal therapy in glioma patients.

Background: In glioma patients, multimodality therapy and recurrent tumor can lead to structural brain tissue damage characterized by pathologic findings in MR and PET imaging. However, little is known about the impact of different types of damage on the fiber architecture of the affected white matter.

Patients And Methods: This study included 121 pretreated patients (median age, 52 years; ECOG performance score, 0 in 48%, 1-2 in 51%) with histomolecularly characterized glioma (WHO grade IV glioblastoma, n=81; WHO grade III anaplastic astrocytoma, n=28; WHO grade III anaplastic oligodendroglioma, n=12), who had a resection, radiotherapy, alkylating chemotherapy, or combinations thereof.

Two Decades of Brain Tumour Imaging with O-(2-[F]fluoroethyl)-L-tyrosine PET: The Forschungszentrum Jülich Experience.

O-(2-[F]fluoroethyl)-L-tyrosine (FET) is a widely used amino acid tracer for positron emission tomography (PET) imaging of brain tumours. This retrospective study and survey aimed to analyse our extensive database regarding the development of FET PET investigations, indications, and the referring physicians' rating concerning the role of FET PET in the clinical decision-making process. Between 2006 and 2019, we performed 6534 FET PET scans on 3928 different patients against a backdrop of growing demand for FET PET.

Static FET PET radiomics for the differentiation of treatment-related changes from glioma progression.

Purpose: To investigate the potential of radiomics applied to static clinical PET data using the tracer O-(2-[F]fluoroethyl)-L-tyrosine (FET) to differentiate treatment-related changes (TRC) from tumor progression (TP) in patients with gliomas.

Patients And Methods: One hundred fifty-one (151) patients with histologically confirmed gliomas and post-therapeutic progressive MRI findings according to the response assessment in neuro-oncology criteria underwent a dynamic amino acid PET scan using the tracer O-(2-[F]fluoroethyl)-L-tyrosine (FET). Thereof, 124 patients were investigated on a stand-alone PET scanner (data used for model development and validation), and 27 patients on a hybrid PET/MRI scanner (data used for model testing).

Case Report: Disruption of Resting-State Networks and Cognitive Deficits After Whole Brain Irradiation for Singular Brain Metastasis.

Long-term survivors of whole brain radiation (WBRT) are at significant risk for developing cognitive deficits, but knowledge about the underlying pathophysiological mechanisms is limited. Therefore, we here report a rare case with a singular brain metastasis treated by resection and WBRT that survived for more than 10 years where we investigated the integrity of brain networks using resting-state functional MRI. A female patient with a left frontal non-small cell lung cancer (NSCLC) brain metastasis had resection and postoperative WBRT (30.

Putaminal y-Aminobutyric Acid Modulates Motor Response to Dopaminergic Therapy in Parkinson's Disease.

Background: Motor response to dopaminergic therapy is a characteristic of patients with Parkinson's disease (PD). Whether nondopaminergic neurotransmitters contribute to treatment response is uncertain.

Objectives: The aim of this study is to determine whether putaminal y-aminobutyric acid (GABA) levels are associated with dopaminergic motor response.

Lesion-Function Analysis from Multimodal Imaging and Normative Brain Atlases for Prediction of Cognitive Deficits in Glioma Patients.

Cognitive deficits are common in glioma patients following multimodality therapy, but the relative impact of different types and locations of treatment-related brain damage and recurrent tumors on cognition is not well understood. In 121 WHO Grade III/IV glioma patients, structural MRI, -(2-[18F]fluoroethyl)-L-tyrosine FET-PET, and neuropsychological testing were performed at a median interval of 14 months (range, 1-214 months) after therapy initiation. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and FET-PET positive tumor sites were semi-automatically segmented and elastically registered to a normative, resting state (RS) fMRI-based functional cortical network atlas and to the JHU atlas of white matter (WM) tracts, and their influence on cognitive test scores relative to a cohort of matched healthy subjects was assessed.

Combined F-FET PET and diffusion kurtosis MRI in posttreatment glioblastoma: differentiation of true progression from treatment-related changes.

Background: Radiological differentiation of tumor progression (TPR) from treatment-related changes (TRC) in pretreated glioblastoma is crucial. This study aimed to explore the diagnostic value of diffusion kurtosis MRI combined with information derived from -(2-[F]-fluoroethyl)-l-tyrosine (F-FET) PET for the differentiation of TPR from TRC in patients with pretreated glioblastoma.

Methods: Thirty-two patients with histomolecularly defined and pretreated glioblastoma suspected of having TPR were included in this retrospective study.

Sequential implementation of DSC-MR perfusion and dynamic [F]FET PET allows efficient differentiation of glioma progression from treatment-related changes.

Purpose: Perfusion-weighted MRI (PWI) and O-(2-[F]fluoroethyl-)-l-tyrosine ([F]FET) PET are both applied to discriminate tumor progression (TP) from treatment-related changes (TRC) in patients with suspected recurrent glioma. While the combination of both methods has been reported to improve the diagnostic accuracy, the performance of a sequential implementation has not been further investigated. Therefore, we retrospectively analyzed the diagnostic value of consecutive PWI and [F]FET PET.

Role of the default mode resting-state network for cognitive functioning in malignant glioma patients following multimodal treatment.

Background: Progressive cognitive decline following multimodal neurooncological treatment is a common observation in patients suffering from malignant glioma. Alterations of the default-mode network (DMN) represent a possible source of impaired neurocognitive functioning and were analyzed in these patients.

Methods: Eighty patients (median age, 51 years) with glioma (WHO grade IV glioblastoma, n = 57; WHO grade III anaplastic astrocytoma, n = 13; WHO grade III anaplastic oligodendroglioma, n = 10) and ECOG performance score 0-1 underwent resting-state functional MRI (rs-fMRI) and neuropsychological testing at a median interval of 13 months (range, 1-114 months) after initiation of therapy.

Radiomics in neuro-oncology: Basics, workflow, and applications.

Over the last years, the amount, variety, and complexity of neuroimaging data acquired in patients with brain tumors for routine clinical purposes and the resulting number of imaging parameters have substantially increased. Consequently, a timely and cost-effective evaluation of imaging data is hardly feasible without the support of methods from the field of artificial intelligence (AI). AI can facilitate and shorten various time-consuming steps in the image processing workflow, e.

Investigation of Cerebral O-(2-[F]Fluoroethyl)-L-Tyrosine Uptake in Rat Epilepsy Models.

Purpose: A recent study reported on high, longer lasting and finally reversible cerebral uptake of O-(2-[F]fluoroethyl)-L-tyrosine ([F]FET) induced by epileptic activity. Therefore, we examined cerebral [F]FET uptake in two chemically induced rat epilepsy models and in patients with focal epilepsy to further investigate whether this phenomenon represents a major pitfall in brain tumor diagnostics and whether [F]FET may be a potential marker to localize epileptic foci.

Procedures: Five rats underwent kainic acid titration to exhibit 3 to 3.

Effect of Zolpidem in the Aftermath of Traumatic Brain Injury: An MEG Study.

In the past two decades, many studies have shown the paradoxical efficacy of zolpidem, a hypnotic used to induce sleep, in transiently alleviating various disorders of consciousness such as traumatic brain injury (TBI), dystonia, and Parkinson's disease. The mechanism of action of this effect of zolpidem is of great research interest. In this case study, we use magnetoencephalography (MEG) to investigate a fully conscious, ex-coma patient who suffered from neurological difficulties for a few years due to traumatic brain injury.

Current trends in the use of O-(2-[F]fluoroethyl)-L-tyrosine ([F]FET) in neurooncology.

The diagnostic potential of PET using the amino acid analogue O-(2-[F]fluoroethyl)-L-tyrosine ([F]FET) in brain tumor diagnostics has been proven in many studies during the last two decades and is still the subject of multiple studies every year. In addition to standard magnetic resonance imaging (MRI), positron emission tomography (PET) using [F]FET provides important diagnostic data concerning brain tumor delineation, therapy planning, treatment monitoring, and improved differentiation between treatment-related changes and tumor recurrence. The pharmacokinetics, uptake mechanisms and metabolism have been well described in various preclinical studies.

Prediction of survival in patients with IDH-wildtype astrocytic gliomas using dynamic O-(2-[F]-fluoroethyl)-L-tyrosine PET.

Purpose: Integrated histomolecular diagnostics of gliomas according to the World Health Organization (WHO) classification of 2016 has refined diagnostic accuracy and prediction of prognosis. This study aimed at exploring the prognostic value of dynamic O-(2-[F]-fluoroethyl)-L-tyrosine (FET) PET in newly diagnosed, histomolecularly classified astrocytic gliomas of WHO grades III or IV.

Methods: Before initiation of treatment, dynamic FET PET imaging was performed in patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA).

Flare Phenomenon in -(2-F-Fluoroethyl)-l-Tyrosine PET After Resection of Gliomas.

PET using -(2-F-fluoroethyl)-l-tyrosine (F-FET) is useful to detect residual tumor tissue after glioma resection. Recent animal experiments detected reactive changes in F-FET uptake at the rim of the resection cavity within the first 2 wk after resection of gliomas. In the present study, we evaluated pre- and postoperative F-FET PET scans of glioma patients with particular emphasis on the identification of reactive changes after surgery.

F-FET PET Imaging in Differentiating Glioma Progression from Treatment-Related Changes: A Single-Center Experience.

In glioma patients, differentiation between tumor progression (TP) and treatment-related changes (TRCs) remains challenging. Difficulties in classifying imaging alterations may result in a delay or an unnecessary discontinuation of treatment. PET using -(2-F-fluoroethyl)-l-tyrosine (F-FET) has been shown to be a useful tool for detecting TP and TRCs.