Neural correlates of standing imagery and execution in Parkinsonian patients: The relevance to striatal dopamine dysfunction.

It has been reported that the cerebellar vermis is equally involved in both motor imagery about axial movement and the actual execution of postural balance in healthy human subjects, but this finding is yet to be explored in Parkinson's disease (PD). We therefore investigated the neuronal responses during observation of standing posture, imagination of standing and the assumption of an upright posture in ten drug-naïve PD patients using positron emission tomography (PET) with [15O]H2O and evaluated dopamine dysfunction by measuring the level of dopamine transporter binding of [11C]CFT. Within-group statistical parametric mapping (SPM) analysis showed similar cerebellar activation during imagination of standing and its real execution between the PD and control groups (12 healthy subjects); i.

Neural correlates of head restraint: Unsolicited neuronal activation and dopamine release.

To minimize motion-related distortion of reconstructed images, conventional positron emission tomography (PET) measurements of the brain inevitably require a firm and tight head restraint. While such a restraint is now a routine procedure in brain imaging, the physiological and psychological consequences resulting from the restraint have not been elucidated. To address this problem, we developed a restraint-free brain PET system and conducted PET scans under both restrained and non-restrained conditions.

In vivo imaging of dopamine D1 receptor and activated microglia in attention-deficit/hyperactivity disorder: a positron emission tomography study.

Alterations in the cortical dopamine system and microglial activation have been implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD), one of neurodevelopmental disorders that can be conventionally treated with a dopamine enhancer (methylphenidate) albeit unsatisfactorily. Here, we investigated the contributions of the dopamine D1 receptor (D1R) and activated microglia and their interactions to the clinical severities in ADHD individuals using positron emission tomography (PET). Twenty-four psychotropic-naïve ADHD individuals and 24 age- and sex-matched typically developing (TD) subjects underwent PET measurements with [C]SCH23390 for the D1R and [C](R)PK11195 for activated microglia as well as assessments of clinical symptoms and cognitive functions.

In vivo mitochondrial and glycolytic impairments in patients with Alzheimer disease.

Objective: In vivo glycolysis-related glucose metabolism and electron transport chain-related mitochondrial activity may be different regionally in the brains of patients with Alzheimer disease (AD). To test this hypothesis regarding AD pathophysiology, we measured the availability of mitochondrial complex-I (MC-I) with the novel PET probe [F]2-tert- butyl-4-chloro-5-2H- pyridazin-3-one ([F]BCPP-EF), which binds to MC-I, and compared [F]BCPP-EF uptake with F-fluorodeoxyglucose ([F]FDG) uptake in the living AD brain.

Methods: First, the total distribution volume (V) of [F]BCPP-EF from 10 normal controls (NCs) was quantified using arterial blood samples and then tested to observe whether V could substitute for the standard uptake value relative to the global count (SUVRg).

Alterations in serotonin transporter and body image-related cognition in anorexia nervosa.

The serotonin system has been implicated in the pathophysiology of anorexia nervosa (AN). A recent report proposed that body image distortion (BID), a core symptom of AN, may relate to abnormalities of the serotonin system, especially the serotonin transporter (5HTT). Positron emission tomography (PET) studies of underweight patients with active AN reported alterations in serotonin receptors, but not 5HTT.

Neuroinflammation following disease modifying therapy in multiple sclerosis: A pilot positron emission tomography study.

Introduction: Chronic activation of microglia accelerates the neurodegenerative process in multiple sclerosis (MS). Although disease modifying therapy (DMT) is reportedly effective for neuroinflammatory responses in MS, the progression of neuroinflammation after DMT remains unclear.

Methods: We evaluated microglial activation in six clinically stable relapsing-remitting MS patients after DMT by quantifying changes in translocator protein (TSPO) density using PET with [C]DPA713, a selective TSPO tracer for microglial activation.

Extrastriatal spreading of microglial activation in Parkinson's disease: a positron emission tomography study.

Background: The neuroinflammatory glial response contributes to the degenerative process in Parkinson's disease (PD). However, the pattern of microglial progression remains unclear.

Methods: We evaluated microglial activation in early stage PD patients by quantifying changes in neuroinflammation using PET with [(11)C]DPA713, a selective PET tracer for microglial activation.

Depiction of microglial activation in aging and dementia: Positron emission tomography with [C]DPA713 versus [C]( R)PK11195.

The presence of activated microglia in the brains of healthy elderly people is a matter of debate. We aimed to clarify the degree of microglial activation in aging and dementia as revealed by different tracers by comparing the binding potential (BP) in various brain regions using a first-generation translocator protein (TSPO) tracer [C]( R)PK11195 and a second-generation tracer [C]DPA713. The BP levels, estimated using simplified reference tissue models, were compared among healthy young and elderly individuals and patients with Alzheimer's disease (AD) and were correlated with clinical scores.

Alterations in α4β2 nicotinic receptors in cognitive decline in Alzheimer's aetiopathology.

Nicotinic acetylcholine receptor subtype α4β2 is considered important in the regulation of attention and memory, and cholinergic degeneration is known as one pathophysiology of Alzheimer's disease. Brain amyloid-β protein deposition is also a key pathological marker of Alzheimer's disease. Recent amyloid-β imaging has shown many cognitively normal subjects with amyloid-β deposits, indicating a missing link between amyloid-β deposition and cognitive decline.

Microglial activation in young adults with autism spectrum disorder.

Context: A growing body of evidence suggests that aberrant immunologic systems underlie the pathophysiologic characteristics of autism spectrum disorder (ASD). However, to our knowledge, no information is available on the patterns of distribution of microglial activation in the brain in ASD.

Objectives: To identify brain regions associated with excessively activated microglia in the whole brain, and to examine similarities in the pattern of distribution of activated microglia in subjects with ASD and control subjects.

In vivo mesolimbic D2/3 receptor binding predicts posttherapeutic clinical responses in restless legs syndrome: a positron emission tomography study.

Although D2/3 agonists have been used as a first-line medication for idiopathic restless legs syndrome (iRLS), findings on D2/3 receptors have been inconsistent. Here, we aimed to clarify the contribution of D2/3 receptor function to the clinical symptoms of iRLS by comparing the binding potential (BP(ND)) of [(11)C]raclopride with clinical improvements after D2/3 stimulation by pramipexole. Eight drug-naïve, iRLS patients and eight age-matched healthy subjects were scanned with positron emission tomography (PET).

Reduced acetylcholinesterase activity in the fusiform gyrus in adults with autism spectrum disorders.

Context: Both neuropsychological and functional magnetic resonance imaging studies have shown deficiencies in face perception in subjects with autism spectrum disorders (ASD). The fusiform gyrus has been regarded as the key structure in face perception. The cholinergic system is known to regulate the function of the visual pathway, including the fusiform gyrus.

Progression from unilateral to bilateral parkinsonism in early Parkinson disease: implication of mesocortical dopamine dysfunction by PET.

Unlabelled: It is still unclear why some early Parkinson disease (PD) patients with unilateral parkinsonism develop bilateral parkinsonism soon after the diagnosis is made as Hoehn and Yahr (HY) stage 1 and others remain stable for a long time. Here, we examined in vivo changes in the brain dopaminergic system using PET with a dopamine transporter radiotracer, (11)C-2-B-carbomethoxy-3B-(4-fluorophenyl) tropane ((11)C-CFT), to elucidate the pathophysiologic characteristics of the dopamine system in early converters.

Methods: Twelve drug-naïve PD patients with HY stage 1 disease and 8 age-matched healthy subjects participated in this study.

Brain serotonin and dopamine transporter bindings in adults with high-functioning autism.

Context: Autism is a neurodevelopmental disorder that is characterized by repetitive and/or obsessive interests and behavior and by deficits in sociability and communication. Although its neurobiological underpinnings are postulated to lie in abnormalities of the serotoninergic and dopaminergic systems, the details remain unknown.

Objective: To determine the occurrence of changes in the binding of serotonin and dopamine transporters, which are highly selective markers for their respective neuronal systems.

Single 20-second acquisition of deep-inspiration breath-hold PET/CT: clinical feasibility for lung cancer.

Unlabelled: This study was designed to compare tumor (18)F-FDG uptake between a single 20-s acquisition of deep-inspiration breath-hold PET/CT and free-breathing PET/CT for lung cancer.

Methods: Before the clinical study, a phantom study was performed to determine the optimum breath-hold time for the PET scan. We studied 47 patients with lung cancer who underwent free-breathing PET/CT with the standard clinical protocol, followed by deep-inspiration breath-hold PET/CT of the thorax.

Altered brain serotonin transporter and associated glucose metabolism in Alzheimer disease.

Unlabelled: Whether preclinical depression is one of the pathophysiologic features of Alzheimer disease (AD) has been under debate. In vivo molecular imaging helps clarify this kind of issue. Here, we examined in vivo changes in the brain serotoninergic system and glucose metabolism by scanning early- to moderate-stage AD patients with and without depression using PET with a radiotracer for the serotonin transporter, (11)C-3-amino-4-(2-dimethylaminomethylphenylsulfanyl) benzonitrile (DASB), and a metabolic marker, (18)F-FDG.

Prognostic value of 18F-FDG PET in patients with head and neck squamous cell cancer.

Objective: This study was designed to assess whether tumor uptake of (18)F-FDG (FDG) expressed as the standardized uptake value (SUV) can be used to predict survival in patients with head and neck cancer. Furthermore, a prognostic maximum SUV was determined with univariate and bivariate analyses.

Conclusion: Low SUVs ( View Article and Find Full Text PDF

[Measurement of radiation exposure to a PET institution driver from patients injected with FDG].

With the recent increase in FDG-PET examinations, concern has mounted regarding radiation exposure to hospital staff and the general public from patients injected with FDG. Because our PET institution is located 15 km from the hospital that provides these examinations, a driver has been designated to transport patients injected with FDG. This study was designed to measure the radiation dose to the driver from these patients (n=28) and to compare it with the estimated dose.

C-choline positron emission tomography in bladder cancer: report of four cases.

Little work has been done with positive emission tomography (PET) in bladder tumors because high urinary excretion of (18)F-FDG makes visualization of the bladder tumor difficult. (11)C-choline has recently been reported as a new tracer which lacks urinary radioactivity. We report the result of (11)C-choline PET in four patients with invasive bladder tumors.

Brain serotonin transporter density and aggression in abstinent methamphetamine abusers.

Context: In animals, methamphetamine is known to have a neurotoxic effect on serotonin neurons, which have been implicated in the regulation of mood, anxiety, and aggression. It remains unknown whether methamphetamine damages serotonin neurons in humans.

Objective: To investigate the status of brain serotonin neurons and their possible relationship with clinical characteristics in currently abstinent methamphetamine abusers.

Cerebral hemodynamics evaluation by near-infrared time-resolved spectroscopy: correlation with simultaneous positron emission tomography measurements.

We compared pharmacologically-perturbed hemodynamic parameters (cerebral blood volume; CBV, and flow; CBF) by acetazolamide administration in six healthy human subjects studied with positron emission tomography (PET) and near-infrared (NIR) time-resolved spectroscopy (TRS) simultaneously to investigate whether NIR-TRS could measure in vivo hemodynamics in the brain tissue quantitatively. Simultaneously with the PET measurements, TRS measurements were performed at the forehead with four different optode spacing from 2 cm to 5 cm. Total hemoglobin and oxygen saturation (SO2) measured by TRS significantly increased after administration of acetazolamide at any optode spacing in all subjects.

Neural substrates in judgment process while playing go: a comparison of amateurs with professionals.

A professional go player shows incomparable ability in judgment during go game. Positron emission tomography (PET) was used to investigate the neural substrates of professional go player's judgment process. Eight professional go players and six amateur players were instructed to think over silently in the opening-stage game (fuseki, territorial planning) problems and the life-or-death (tsume, checkmate judgment) problems presented on the monitor in front of them for 60 s of H2 15O PET scans and to state the answer afterwards.

11C-choline positron emission tomography in prostate cancer: primary staging and recurrent site staging.

Objectives: To evaluate the usefulness of 11C-choline positron emission tomography (PET) for primary staging and re-staging of prostate cancer.

Patients And Methods: 11C-choline PET, a total of 22 scans, was performed on 13 patients with histologically proven prostate cancer in primary staging (n = 6) and recurrent site staging; following radical prostatectomy (n = 5) and following radiation therapy (n = 3). In 1 patient, 11C-choline PET was performed in both primary staging and re-staging.

Microglial activation and dopamine terminal loss in early Parkinson's disease.

Neuroinflammatory glial response may contribute to degenerative processes in Parkinson's disease (PD). To investigate changes in microglial activity associated with changes in the presynaptic dopamine transporter density in the PD brain in vivo, we studied 10 early-stage drug-naive PD patients twice using positron emission tomography with a radiotracer for activated microglia [(11)C](R)-PK11195 and a dopamine transporter marker [(11)C]CFT. Quantitative levels of binding potentials (BPs) of [(11)C](R)-PK11195 and [(11)C]CFT in the nigrostriatal pathway were estimated by compartment analyses.

Orthostatic posture affects brain hemodynamics and metabolism in cerebrovascular disease patients with and without coronary artery disease: a positron emission tomography study.

To investigate whether a physiological change in the orthostatic condition is associated with a deterioration of cerebrovascular and metabolic homeostasis in patients with neurocardiovascular compromises, we examined 10 patients with unilateral carotid artery occlusive disease (CVD), 6 CVD patients with coronary artery disease (CVDC), and 10 healthy subjects scanned twice under supine and sitting conditions by positron emission tomography (PET). Repeated measures analysis of variance showed significant reductions in regional cerebral blood flow (rCBF) and cerebral oxygen metabolism (rCMRO2) and tendency of increase in oxygen extraction fraction (OEF) in the affected-side parietal cortex during assuming of upright posture in the CVDC group, and there was a significant OEF increase to maintain rCMRO2 constant during sitting in the CVD counterpart. In this ischemic region, there were negative correlations between changes in OEF and rCBF in the CVD (P < 0.