Identification of a metabolic brain network characterizing essential tremor.

The neuronal correlate of tremor genesis and cognitive function in essential tremor (ET) and its modulation by deep brain stimulation (DBS) are poorly understood. To explore the underlying metabolic topography of motor and cognitive symptoms, sixteen ET patients (age 63.6 ± 49.

Increasing striatal dopamine release through repeated bouts of theta burst transcranial magnetic stimulation of the left dorsolateral prefrontal cortex. A 18F-desmethoxyfallypride positron emission tomography study.

Introduction: Transcranial Magnetic Stimulation (TMS) can modulate fronto-striatal connectivity in the human brain. Here Positron Emission Tomography (PET) and neuro-navigated TMS were combined to investigate the dynamics of the fronto-striatal connectivity in the human brain. Employing 18F-DesmethoxyFallypride (DMFP) - a Dopamine receptor-antagonist - the release of endogenous dopamine in the striatum in response to time-spaced repeated bouts of excitatory, intermittent theta burst stimulation (iTBS) of the Left-Dorsolateral Prefrontal Cortex (L-DLPFC) was measured.

Tc‑labeled single-domain antibody for SPECT/CT assessment of HER2 expression in diverse cancer types.

Unlabelled: The expression status of human epidermal growth factor receptor 2 (HER2) in cancer predicts response to HER2-targeted therapy. Therefore, its accurate determination is of utmost importance. In recent years, there has been an increase in research on noninvasive techniques for molecular imaging, as this method offers the advantages of a more accurate determination of HER2 status without the need for multiple biopsies.

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).

Assessment of the lymphatic system by indirect lymphography in patients with post-thrombotic syndrome.

Objective: Alterations in lower extremity lymph drainage caused by chronic venous obstruction (CVO) have not been well studied, partially because of a lack of standardized imaging modalities to assess the quality of lymphatic drainage in the lower extremities of patients with post-thrombotic syndrome (PTS). However, these changes are likely to have an impact on the severity of the disease and clinical outcomes of interventions. In the present study, we investigated the feasibility and diagnostic value of preintervention indirect lymphography in patients with CVO and their pre- and postintervention Villalta scores.

Sodium [F]Fluoride PET Can Efficiently Monitor In Vivo Atherosclerotic Plaque Calcification Progression and Treatment.

Given the high sensitivity and specificity of sodium [F]Fluoride (Na[F]F) for vascular calcifications and positive emerging data of vitamin K on vascular health, the aim of this study is to assess the ability of Na[F]F to monitor therapy and disease progression in a unitary atherosclerotic mouse model. ApoE mice were placed on a Western-type diet for 12-weeks and then split into four groups. The early stage atherosclerosis group received a chow diet for an additional 12-weeks, while the advanced atherosclerosis group continued the Western-type diet.

MR and PET-CT monitoring of tissue-engineered vascular grafts in the ovine carotid artery.

The modification of biomaterials to comply with clinically employed monitoring techniques is a promising strategy to support clinical translation in regenerative medicine. Here, multimodal imaging of tissue-engineered vascular grafts (TEVG) was enabled by functionalizing the textile scaffold with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. The resulting MR-imageable grafts (iTEVG) were monitored non-invasively throughout their whole life-cycle, from initial quality control to longitudinal functional evaluation in an ovine model for up to 8 weeks.

Lower [F]fallypride binding to dopamine D receptors in frontal brain areas in adults with 22q11.2 deletion syndrome: a positron emission tomography study.

Background: The 22q11.2 deletion syndrome (22q11DS) is caused by a deletion on chromosome 22 locus q11.2.

In vivo Molecular Imaging of Glutamate Carboxypeptidase II Expression in Re-endothelialisation after Percutaneous Balloon Denudation in a Rat Model.

The short- and long-term success of intravascular stents depends on a proper re-endothelialisation after the intervention-induced endothelial denudation. The aim of this study was to evaluate the potential of in vivo molecular imaging of glutamate carboxypeptidase II (GCPII; identical with prostate-specific membrane antigen PSMA) expression as a marker of re-endothelialisation. Fifteen Sprague Dawley rats underwent unilateral balloon angioplasty of the common carotid artery (CCA).

Striatal dopamine release and impaired reinforcement learning in adults with 22q11.2 deletion syndrome.

22q11.2 deletion syndrome (22q11DS) is a genetic disorder caused by a microdeletion on chromosome 22q11.2 and associated with an increased risk for developing psychosis.

Evaluation of a Pretargeting Strategy for Molecular Imaging of the Prostate Stem Cell Antigen with a Single Chain Antibody.

In pretargeted radio-immunotherapy, the gradual administration of a non-radioactive tumor antigen-addressing antibody-construct and the subsequent application of a radioactive labeled, low molecular weight substance enable a highly effective and selective targeting of tumor tissue. We evaluated this concept in prostate stem cell antigen (PSCA)-positive cancers using the antigen-specific, biotinylated single chain antibody scFv(AM1)-P-BAP conjugated with tetrameric neutravidin. To visualize the systemic biodistribution, a radiolabeled biotin was injected to interact with scFv(AM1)-P-BAP/neutravidin conjugate.

Impact of Glutathione Modulation on Stability and Pharmacokinetic Profile of Redox-Sensitive Nanogels.

Nanoparticles degradable upon external stimuli combine pharmacokinetic features of both small molecules as well as large nanoparticles. However, despite promising preclinical results, several redox responsive disulphide-linked nanoparticles failed in clinical translation, mainly due to their unexpected in vivo behavior. Glutathione (GSH) is one of the most evaluated antioxidants responsible for disulfide degradation.

Multistage Passive and Active Delivery of Radiolabeled Nanogels for Superior Tumor Penetration Efficiency.

Development of nanosized drug delivery systems in cancer therapy is directed toward improving tumor selectivity and minimizing damages of healthy tissue. We introduce a delivery system with synergistic optimization and combination of passive and active targeting strategies. The approach is based on radiopeptide labeled redox sensitive hydrophilic nanogels, which exploit passive targeting by the enhanced permeability and retention effect while avoiding elimination by the mononuclear phagocyte system and fast hepatic and renal clearance.

The reconstruction algorithm used for [Ga]PSMA-HBED-CC PET/CT reconstruction significantly influences the number of detected lymph node metastases and coeliac ganglia.

Purpose: To investigate whether the numbers of lymph node metastases and coeliac ganglia delineated on [Ga]PSMA-HBED-CC PET/CT scans differ among datasets generated using different reconstruction algorithms.

Methods: Data were constructed using the BLOB-OS-TF, BLOB-OS and 3D-RAMLA algorithms. All reconstructions were assessed by two nuclear medicine physicians for the number of pelvic/paraaortal lymph node metastases as well the number of coeliac ganglia.

Metabolic tumour volume of anal carcinoma on (18)FDG PET/CT before combined radiochemotherapy is the only independant determinant of recurrence free survival.

Aim: to determine whether [(18)F]2-fluoro-2-deoxyglucose (FDG) positron emission tomography and X-ray computed tomography (PET/CT) findings and metabolic parameters before combined chemo- and radiotherapy (CRT) have a prognostic value in patients with anal carcinoma.

Materials And Methods: 45 patients with anal cancer who underwent pre-treatment FDG-PET/CT were included. Metabolic parameters, recurrence and anal carcinoma specific survival were analyzed.

Early-Life Stress Affects Stress-Related Prefrontal Dopamine Activity in Healthy Adults, but Not in Individuals with Psychotic Disorder.

Early life stress may have a lasting impact on the developmental programming of the dopamine (DA) system implicated in psychosis. Early adversity could promote resilience by calibrating the prefrontal stress-regulatory dopaminergic neurotransmission to improve the individual's fit with the predicted stressful environment. Aberrant reactivity to such match between proximal and distal environments may, however, enhance psychosis disease risk.

Effects of Smoking Cessation on Presynaptic Dopamine Function of Addicted Male Smokers.

Background: There is evidence of abnormal cerebral dopamine transmission in nicotine-dependent smokers, but it is unclear whether dopaminergic abnormalities are due to acute nicotine abuse or whether they persist with abstinence. We addressed this question by conducting longitudinal positron emission tomography (PET) examination of smokers before and after 3 months of abstinence.

Methods: We obtained baseline 6-[(18)F]fluoro-L-DOPA (FDOPA)-PET scans in 15 nonsmokers and 30 nicotine-dependent smokers, who either smoked as per their usual habit or were in acute withdrawal.

MAOA-VNTR polymorphism modulates context-dependent dopamine release and aggressive behavior in males.

A recent [(18)F]FDOPA-PET study reports negative correlations between dopamine synthesis rates and aggressive behavior. Since dopamine is among the substrates for monoamine oxidase A (MAOA), this investigation examines whether functional allelic variants of the MAOA tandem repeat (VNTR) promotor polymorphism, which is known to modulate aggressive behavior, influences dopamine release and aggression in response to violent visual stimuli. We selected from a genetic prescreening sample, strictly case-matched groups of 2×12 healthy male subjects with VNTRs predictive of high (MAOA-High) and low (MAOA-Low) MAOA expression.

Comparison of automatic versus manual procedures for the quantification of dopamine D2 receptor availability using I-123-IBZM-SPECT.

Introduction: I-123-IBZM-SPECT is often used to differentiate between idiopathic Parkinson's syndrome and atypical parkinsonian syndromes. The aim of this study was to compare three different procedures to quantify the receptor availability of striatal dopamine D2 receptors. (a) Manual quantification performed using individually adjusted volume of interests sets (mVoi).

No evidence for attenuated stress-induced extrastriatal dopamine signaling in psychotic disorder.

Stress is an important risk factor in the etiology of psychotic disorder. Preclinical work has shown that stress primarily increases dopamine (DA) transmission in the frontal cortex. Given that DA-mediated hypofrontality is hypothesized to be a cardinal feature of psychotic disorder, stress-related extrastriatal DA release may be altered in psychotic disorder.

Acute and sustained effects of methylphenidate on cognition and presynaptic dopamine metabolism: an [18F]FDOPA PET study.

Methylphenidate (MPH) inhibits the reuptake of dopamine and noradrenaline. PET studies with MPH challenge show increased competition at postsynaptic D2/3-receptors, thus indirectly revealing presynaptic dopamine release. We used [(18)F]fluorodopamine ([(18)F]FDOPA)-PET in conjunction with the inlet-outlet model (IOM) of Kumakura et al.

In-vivo detection of the erythropoietin receptor in tumours using positron emission tomography.

Objective: Recombinant human erythropoietin (rhuEpo) is used clinically to treat anaemia. However, rhuEpo-treated cancer patients show decreased survival rates and erythropoietin receptor (EpoR) expression has been found in patient tumour tissue. Thus, rhuEpo application might promote EpoR(+) tumour progression.

Simulation-based partial volume correction for dopaminergic PET imaging: Impact of segmentation accuracy.

Aim: Partial volume correction (PVC) is an essential step for quantitative positron emission tomography (PET). In the present study, PVELab, a freely available software, is evaluated for PVC in (18)F-FDOPA brain-PET, with a special focus on the accuracy degradation introduced by various MR-based segmentation approaches.

Methods: Four PVC algorithms (M-PVC; MG-PVC; mMG-PVC; and R-PVC) were analyzed on simulated (18)F-FDOPA brain-PET images.

The impact of dopamine on aggression: an [18F]-FDOPA PET Study in healthy males.

Cerebral dopamine (DA) transmission is thought to be an important modulator for the development and occurrence of aggressive behavior. However, the link between aggression and DA transmission in humans has not been investigated using molecular imaging and standardized behavioral tasks. We investigated aggression as a function of DA transmission in a group of (N = 21) healthy male volunteers undergoing 6-[18F]-fluoro-L-DOPA (FDOPA)-positron emission tomography (PET) and a modified version of the Point Subtraction Aggression Paradigm (PSAP).