Added prognostic value of DCE blood volume imaging in patients with suspected recurrent or residual glioblastoma-A hybrid [F]FET PET/MRI study.

Background: Magnetic resonance imaging (MRI) cerebral blood volume (CBV) measurements improve the diagnosis of recurrent gliomas. The study investigated the prognostic value of dynamic contrast-enhanced (DCE) CBV imaging in treated IDH wildtype glioblastoma when added to MRI or amino acid positron emission tomography (PET).

Methods: Hybrid [F]FET PET/MRI with 2CXM (2-compartment exchange model) DCE from 86 adult patients with suspected recurrent or residual glioblastoma were retrospectively analyzed.

Magnetic resonance imaging and o-(2-[F]fluoroethyl)-l-tyrosine positron emission tomography for early response assessment of nivolumab and bevacizumab in patients with recurrent high-grade astrocytic glioma.

Background: In the present study, early response assessment by o-(2-[F]fluoroethyl)-l-tyrosine (FET) positron emission tomography (PET) and contrast-enhanced magnetic resonance imaging (MRI) were investigated in a phase II open-label single-center study of nivolumab plus bevacizumab for recurrent high-grade astrocytic glioma.

Methods: Twenty patients with nonresectable first recurrence of high-grade astrocytic glioma after EORTC/NCIC protocol underwent [F]FET PET/MRI at baseline and after 2 cycles of treatment. Whole brain values of contrast-enhancing volume on MRI (CEV), of the mean (TBR) and maximal tumor-to-background ratio (TBR), and of metabolically active volume (MTV) on [F]FET PET were obtained.

A prospective clinical study of the influence of oral protein intake on [F]FET-PET uptake and test-retest repeatability in glioma.

Background: O-(2-[F]fluoroethyl)-L-tyrosine positron emission tomography ([F]FET PET) scanning is used in routine clinical management and evaluation of gliomas with a recommended 4 h prior fasting. Knowledge of test-retest variation of [F]FET PET imaging uptake metrics and the impact of accidental protein intake can be critical for interpretation. The aim of this study was to investigate the repeatability of [F]FET-PET metrics and to assess the impact of protein-intake prior to [F]FET PET scanning of gliomas.

The cingulate island sign in a mixed memory clinical cohort: Prevalence and diagnostic accuracy.

Introduction: Visual rating of the cingulate island sign (CIS) on [F]fluorodeoxyglucose ([F]FDG) positron emission tomography (PET) has a high specificity for dementia with Lewy bodies (DLB) in selected cohorts such as DLB versus Alzheimer's disease (AD). In a mixed memory clinical population this study aimed to uncover the prevalence of CIS, the diagnostic accuracy for DLB, and the relationship between CIS and disease severity.

Methods: CIS on [F]FDG-PET was retrospectively assessed with the visual CIS rating scale (CISRs) in 1000 patients with a syndrome diagnosis of mild cognitive impairment (MCI) or dementia with no restrictions in etiological diagnosis.

Long-term prognostic value of [O]HO PET imaging in patients suspected for cerebral hemodynamic insufficiency.

Objectives: Quantitative regional cerebral perfusion (rCBF) measurements using [O]HO PET with arterial cannulation and acetazolamide (ACZ) challenge have been reserved to identify high-risk patients that are candidates for by-pass operation. We aimed to assess the prognostic value of various parameters in quantitative [O]HO PET measurements in patients not subsequently undergoing surgery.

Methods: We identified 32 eligible patients who underwent [O]HO brain PET imaging for suspicion of hemodynamic insufficiency between 2009 and 2020.

Estimation of brain amyloid accumulation using deep learning in clinical [C]PiB PET imaging.

Introduction: Estimation of brain amyloid accumulation is valuable for evaluation of patients with cognitive impairment in both research and clinical routine. The development of high throughput and accurate strategies for the determination of amyloid status could be an important tool in patient selection for clinical trials and amyloid directed treatment. Here, we propose the use of deep learning to quantify amyloid accumulation using standardized uptake value ratio (SUVR) and classify amyloid status based on their PET images.

Clinical validation of the cingulate island sign visual rating scale in dementia with Lewy bodies.

Introduction: The cingulate island sign (CIS) is a metabolic pattern on [F]fluorodeoxyglucose ([F]FDG) positron emission tomography (PET) associated with dementia with Lewy bodies (DLB). The aim of this study was to validate the visual CIS rating scale (CISRs) for the diagnosis of DLB and to explore the clinical correlates.

Methods: This single-center study included 166 DLB patients and 161 patients with Alzheimer's disease (AD).

Expanding the Spectrum of Stress-Induced Childhood-Onset Neurodegeneration with Variable Ataxia and Seizures (CONDSIAS).

Stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS) is an extremely rare, autosomal recessive neurodegenerative disorder. It is caused by biallelic pathogenic variants in the ADPRS gene, which encodes an enzyme involved in DNA repair, and is characterized by exacerbations in relation to physical or emotional stress, and febrile illness. We report a 24-year-old female, who was compound heterozygous for two novel pathogenic variants revealed by whole exome sequencing.

DeepDixon synthetic CT for [ PET/MRI attenuation correction of post-surgery glioma patients with metal implants.

Purpose: Conventional magnetic resonance imaging (MRI) can for glioma assessment be supplemented by positron emission tomography (PET) imaging with radiolabeled amino acids such as O-(2-[F]fluoroethyl)-L-tyrosine ([F]FET), which provides additional information on metabolic properties. In neuro-oncology, patients often undergo brain and skull altering treatment, which is known to challenge MRI-based attenuation correction (MR-AC) methods and thereby impact the simplified semi-quantitative measures such as tumor-to-brain ratio (TBR) used in clinical routine. The aim of the present study was to examine the applicability of our deep learning method, DeepDixon, for MR-AC in [F]FET PET/MRI scans of a post-surgery glioma cohort with metal implants.

A zero-dose synthetic baseline for the personalized analysis of [F]FDG-PET: Application in Alzheimer's disease.

Purpose: Brain 2-Deoxy-2-[F]fluoroglucose ([F]FDG-PET) is widely used in the diagnostic workup of Alzheimer's disease (AD). Current tools for uptake analysis rely on non-personalized templates, which poses a challenge as decreased glucose uptake could reflect neuronal dysfunction, or heterogeneous brain morphology associated with normal aging. Overcoming this, we propose a deep learning method for synthesizing a personalized [F]FDG-PET baseline from the patient's own MRI, and showcase its applicability in detecting AD pathology.

Automatic detection and delineation of pediatric gliomas on combined [F]FET PET and MRI.

Introduction: Brain and central nervous system (CNS) tumors are the second most common cancer type in children and adolescents. Positron emission tomography (PET) imaging with radiolabeled amino acids visualizes the amino acid uptake in brain tumor cells compared with the healthy brain tissue, which provides additional information over magnetic resonance imaging (MRI) for differential diagnosis, treatment planning, and the differentiation of tumor relapse from treatment-related changes. However, tumor delineation is a time-consuming task subject to inter-rater variability.

Diagnostic yield of simultaneous dynamic contrast-enhanced magnetic resonance perfusion measurements and [F]FET PET in patients with suspected recurrent anaplastic astrocytoma and glioblastoma.

Purpose: Both amino acid positron emission tomography (PET) and magnetic resonance imaging (MRI) blood volume (BV) measurements are used in suspected recurrent high-grade gliomas. We compared the separate and combined diagnostic yield of simultaneously acquired dynamic contrast-enhanced (DCE) perfusion MRI and O-(2-[F]-fluoroethyl)-L-tyrosine ([F]FET) PET in patients with anaplastic astrocytoma and glioblastoma following standard therapy.

Methods: A total of 76 lesions in 60 hybrid [F]FET PET/MRI scans with DCE MRI from patients with suspected recurrence of anaplastic astrocytoma and glioblastoma were included retrospectively.

Deep learning based low-activity PET reconstruction of [C]PiB and [F]FE-PE2I in neurodegenerative disorders.

Purpose: Positron Emission Tomography (PET) can support a diagnosis of neurodegenerative disorder by identifying disease-specific pathologies. Our aim was to investigate the feasibility of using activity reduction in clinical [F]FE-PE2I and [C]PiB PET/CT scans, simulating low injected activity or scanning time reduction, in combination with AI-assisted denoising.

Methods: A total of 162 patients with clinically uncertain Alzheimer's disease underwent amyloid [C]PiB PET/CT and 509 patients referred for clinically uncertain Parkinson's disease underwent dopamine transporter (DAT) [F]FE-PE2I PET/CT.

High-Grade Glioma Treatment Response Monitoring Biomarkers: A Position Statement on the Evidence Supporting the Use of Advanced MRI Techniques in the Clinic, and the Latest Bench-to-Bedside Developments. Part 1: Perfusion and Diffusion Techniques.

Objective: Summarize evidence for use of advanced MRI techniques as monitoring biomarkers in the clinic, and highlight the latest bench-to-bedside developments.

Methods: Experts in advanced MRI techniques applied to high-grade glioma treatment response assessment convened through a European framework. Current evidence regarding the potential for monitoring biomarkers in adult high-grade glioma is reviewed, and individual modalities of perfusion, permeability, and microstructure imaging are discussed (in Part 1 of two).

High-Grade Glioma Treatment Response Monitoring Biomarkers: A Position Statement on the Evidence Supporting the Use of Advanced MRI Techniques in the Clinic, and the Latest Bench-to-Bedside Developments. Part 2: Spectroscopy, Chemical Exchange Saturation, Multiparametric Imaging, and Radiomics.

Objective: To summarize evidence for use of advanced MRI techniques as monitoring biomarkers in the clinic, and to highlight the latest bench-to-bedside developments.

Methods: The current evidence regarding the potential for monitoring biomarkers was reviewed and individual modalities of metabolism and/or chemical composition imaging discussed. Perfusion, permeability, and microstructure imaging were similarly analyzed in Part 1 of this two-part review article and are valuable reading as background to this article.

Widening the spectrum of spinocerebellar ataxia autosomal recessive type 10 (SCAR10).

Biallelic pathogenic variants in the gene cause spinocerebellar ataxia recessive type 10. We report two patients, both compound heterozygous for variants, including two novel variants. Both patients had onset of cerebellar ataxia in adulthood with slow progression and presented corticospinal tract signs, eye movement abnormalities and cognitive executive impairment.

Get up early: Revealing behavioral responses of sandeel to ocean warming using commercial catch data.

Warming of the oceans and shifts in the timing of annual key events are likely to cause behavioral changes in species showing a high degree of site fidelity. While this is well studied in terrestrial systems, there are fewer examples from the marine environment. Sandeel () is a small eel-shaped teleost fish with strong behavioral attachment to sandy habitats in which they are buried from late summer through winter.

Deep-learning-based attenuation correction in dynamic [O]HO studies using PET/MRI in healthy volunteers.

Quantitative [O]HO positron emission tomography (PET) is the accepted reference method for regional cerebral blood flow (rCBF) quantification. To perform reliable quantitative [O]HO-PET studies in PET/MRI scanners, MRI-based attenuation-correction (MRAC) is required. Our aim was to compare two MRAC methods (RESOLUTE and DeepUTE) based on ultrashort echo-time with computed tomography-based reference standard AC (CTAC) in dynamic and static [O]HO-PET.

Diagnostic accuracy and clinical impact of [18F]FET PET in childhood CNS tumors.

Background: Central nervous system (CNS) tumors cause the highest death rates among childhood cancers, and survivors frequently have severe late effects. Magnetic resonance imaging (MRI) is the imaging modality of choice, but its specificity can be challenged by treatment-induced signal changes. In adults, O-(2-[18F]fluoroethyl)-l-tyrosine ([18F]FET) PET can assist in interpreting MRI findings.

Regional and interindividual relationships between cerebral perfusion and oxygen metabolism.

Quantitative measurements of resting cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO) show large between-subject and regional variability, but the relationships between CBF and CMRO measurements regionally and globally are not fully established. Here, we investigated the between-subject and regional associations between CBF and CMRO measures with independent and quantitative PET techniques. We included resting CBF and CMRO measurements from 50 healthy volunteers (aged 22-81 yr), and calculated the regional and global values of oxygen delivery (Do) and oxygen extraction fraction (OEF).

Validation of kinetic modeling of [O]HO PET using an image derived input function on hybrid PET/MRI.

In present study we aimed to validate the use of image-derived input functions (IDIF) in the kinetic modeling of cerebral blood flow (CBF) measured by [O]HO PET by comparing with the accepted reference standard arterial input function (AIF). Additional comparisons were made to mean cohort AIF and CBF values acquired by methodologically independent phase-contrast mapping (PCM) MRI. Using hybrid PET/MRI an IDIF was generated by measuring the radiotracer concentration in the internal carotid arteries and correcting for partial volume effects using the intravascular volume measured from MRI-angiograms.

Comparison of the clinical impact of 2-[18F]FDG-PET and cerebrospinal fluid biomarkers in patients suspected of Alzheimer's disease.

Background: The two biomarkers 2-[18F]FDG-PET and cerebrospinal fluid biomarkers are both recommended to support the diagnosis of Alzheimer's disease. However, there is a lack of knowledge for the comparison of the two biomarkers in a routine clinical setting.

Objective: The aim was to compare the clinical impact of 2-[18F]FDG-PET and cerebrospinal fluid biomarkers on diagnosis, prognosis, and patient management in patients suspected of Alzheimer's disease.

C9ORF72 hexanucleotide repeat expansion with Alzheimer's disease-like clinical phenotype: A case report with results from neuropsychology, CSF, FDG-PET, and PiB-PET.

A thorough family history and relevant investigation program are essential to settle accurate diagnosis when clinical presentation is atypical or with a mixed picture.

Effect of blood glucose and body weight on image quality in brain [18F]FDG PET imaging.

Objectives: The aims of the present study were to assess the influence of mild to moderate hyperglycaemia and body weight on brain 2-[F]fluoro-2-deoxy-D-glucose ([F]FDG) PET, and to what extent a simple algorithm for maintaining count density may compensate for these effects.

Methods: We prospectively included 63 patients undergoing routine brain [F]FDG PET. Scan time and injected activity were adjusted in patients with hyperglycaemia or increased body weight.

AI-driven attenuation correction for brain PET/MRI: Clinical evaluation of a dementia cohort and importance of the training group size.

Introduction: Robust and reliable attenuation correction (AC) is a prerequisite for accurate quantification of activity concentration. In combined PET/MRI, AC is challenged by the lack of bone signal in the MRI from which the AC maps has to be derived. Deep learning-based image-to-image translation networks present itself as an optimal solution for MRI-derived AC (MR-AC).