Reduced cerebral DOPA uptake in adult patients suffering from phenylketonuria

Equilibrium in [18F]fallypride PET

Choice of reference area in studies of Alzheimer's disease using positron emission tomography with fluorodeoxyglucose-F18

At present, there is still no consensus on the choice of the reference area in positron emission tomography (PET) studies of Alzheimer's disease (AD). In this study, PET scans with fluorodeoxyglucose-F18 were carried out in the following groups of subjects: 47 patients with probable AD, 8 patients with mild cognitive impairment, and 15 age-similar healthy subjects. Scans normalized to the cerebral global mean (CGM), cerebellum (CBL), and the primary sensorimotor cortex (SMC). We evaluated the effect of the different count normalization procedures on the accuracy of (18)F-FDG PET to detect AD-specific metabolic abnormalities (voxel-based group comparison) and to differentiate between patient…

Relationship between prefrontal cognitive functions and dopaminergic transmission: A [18F]-fluoro-l-DOPA PET study

Noninvasive assessment of Crohn's disease activity: a comparison of 18F-fluorodeoxyglucose positron emission tomography, hydromagnetic resonance imaging, and granulocyte scintigraphy with labeled antibodies.

Detection of disease activity in Crohn's disease (CD) is of crucial importance for diagnosis and management of the disease. Noninvasive methods for monitoring are desirable and comprise hydromagnetic resonance imaging (hydro-MRI) and leukocyte scintigraphy. In addition, a recent case report indicated the potential of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to assess CD activity. However, comparative prospective studies are lacking.Between February, 1999 and August, 2000, 59 patients with CD were enrolled in a prospective study to assess disease activity by FDG-PET, hydro-MRI, and immunoscintigraphy with anti-nonspecific cross-reacting antigen 95 antigranulocyte antibod…

Comparison of MRI and VQ-SPECT as a Screening Test for Patients With Suspected CTEPH: CHANGE-MRI Study Design and Rationale

The diagnostic strategy for chronic thromboembolic pulmonary hypertension (CTEPH) is composed of two components required for a diagnosis of CTEPH: the presence of chronic pulmonary embolism and an elevated pulmonary artery pressure. The current guidelines require that ventilation–perfusion single-photon emission computed tomography (VQ-SPECT) is used for the first step diagnosis of chronic pulmonary embolism. However, VQ-SPECT exposes patients to ionizing radiation in a radiation sensitive population. The prospective, multicenter, comparative phase III diagnostic trial CTEPH diagnosis Europe - MRI (CHANGE-MRI, ClinicalTrials.gov identifier NCT02791282) aims to demonstrate whether functional…

Dominance for Vestibular Cortical Function in the Non-dominant Hemisphere

The aim of this (15)O-labelled H(2)O bolus positron emission tomography (PET) study was to analyse the hemispheric dominance of the vestibular cortical system. Therefore, the differential effects of caloric vestibular stimulation (right or left ear irrigation with warm water at 44 degrees C) on cortical and subcortical activation were studied in 12 right-handed and 12 left-handed healthy volunteers. Caloric irrigation induces a direction-specific sensation of rotation and nystagmus. Significant regional cerebral blood flow increases were found in a network within both hemispheres, including the superior frontal gyrus/sulcus, the precentral gyrus and the inferior parietal lobule with the sup…

Kinetic analysis of functional images: The case for a practical approach to performance prediction

We present the first parallel medical application for the analysis of dynamic positron emission tomography (PET) images together with a practical performance model. The parallel application may improve the diagnosis for a patient (e. g. in epilepsy surgery) because it enables the fast computation of parametric images on a pixed level as opposed to the traditionally used region of interest (ROI) approach which is applied to determine an average parametric value for a particular anatomic region of the brain. We derive the performance model from the application context and show its relation to abstract machine models. We demonstrate the accuracy of the model to predict the runtime of the appli…

Decreased dopamine D2/D3-receptor binding in temporal lobe epilepsy: an [18F]fallypride PET study.

Summary: Purpose: Although animal data are suggestive, evidence for an alteration of the extrastriatal dopaminergic system in human focal epilepsy is missing. Methods: To quantify D2/D3-receptor density, we studied seven patients with temporal lobe epilepsy (TLE) and nine agematched controls with positron emission tomography (PET) by using the high-affinity dopamine D2/D3-receptor ligand [ 18 F]Fallypride ([ 18 F]FP) suitable for imaging extrastriatal binding. TLE was defined by interictal and ictal video-EEG, magnetic resonance imaging (MRI), and [ 18 F]fluorodeoxyglucose ([ 18 F]FDG)-PET and was due to hippocampal sclerosis (HS), based on histology in all patients. Primary analysis was ba…

Anti-TNF-Antikörper zur Therapie von entzündlichen Darmstenosen bei Morbus Crohn

Stenoses are a frequent complication in patients with Crohn's disease and represent a major diagnostic and therapeutic challenge. The proper assessment of the nature of a stenosis as inflammatory or fibrotic is critical for appropriate treatment, since symptomatic fibrotic stenoses require surgical resection. Standard diagnostic procedures to assess the nature of a stenosis include endoscopy, conventional contrast radiography and magnetic resonance tomography. Recent data suggest, that the positron-emission-tomography possesses a high sensitivity and specificity to confirm inflammatory activity in the bowel. The recombinant monoclonal anti-TNF-antibody Infliximab (Remicade) has been approve…

SPECT-Untersuchungen mit dem 123I-markierten Dopamintransporter-Liganden FP-CIT (DaTSCANTM)

ZusammenfassungDie S1-Leitlinie soll bei der Indikationsstellung, Durchführung, Interpretation und Befundung von SPECT-Untersuchungen des Dopamintransporters (DAT) mit DaTSCANTM unterstützen. Gegenüber der Vorgängerversion von 2007 berücksichtigt die vorliegende Aktualisierung und Überarbeitung die neuere wissenschaftliche Literatur, zwischenzeitlich veröffentlichte Guidelines der europäischen (EANM) und amerikanischen Fachgesellschaften (SNM), sowie die aktuelle Fassung der S3-Leitlinie „Idiopathisches Parkinson-Syndrom“ der Deutschen Gesellschaft für Neurologie. Zudem finden neue technische Möglichkeiten Berücksichtigung.

Association between Cognitive Performance and Cortical Glucose Metabolism in Patients with Mild Alzheimer’s Disease

<i>Background:</i> Neuronal and synaptic function in Alzheimer’s disease (AD) is measured in vivo by glucose metabolism using positron emission tomography (PET). <i>Objective:</i> We hypothesized that neuronal activation as measured by PET is a more sensitive index of neuronal dysfunction than activity during rest. We investigated if the correlations between dementia severity as measured with the Mini Mental State Examination (MMSE) and glucose metabolism are an artifact of brain atrophy. <i>Method:</i> Glucose metabolism was measured using [<sup>18</sup>F]fluorodeoxyglucose PET during rest and activation due to audiovisual stimulation in 13 m…

Fixation suppression of optokinetic nystagmus modulates cortical visual-vestibular interaction.

Water activation positron emission tomography and statistical group analysis were used to evaluate differences in activation-deactivation patterns during small-field visual motion stimulation, eliciting rightward optokinetic nystagmus and its fixation suppression in 12 healthy volunteers. Bilateral patterns of activation in the visual cortex, including the motion-sensitive area MT/V5, and deactivations in an assembly of vestibular areas (posterior insula, thalamus, anterior cingulate gyrus) during optokinetic nystagmus was markedly diminished or totally absent during its fixation suppression. This finding agrees with the concept of a reciprocal inhibitory interaction between the visual-opto…

Prognostic Factors Determining Long-Term Survival in Well-Differentiated Thyroid Cancer: An Analysis of Four Hundred Eighty-Four Patients Undergoing Therapy and Aftercare at the Same Institution

Identification of the prognostic factors relevant for long-term survival in differentiated thyroid cancer in a homogenously treated patient cohort in order to allow a better initial risk stratification.Four hundred eighty-four (358 females/126 males) patients with differentiated thyroid cancer (330 papillary [68.2%]; 154 follicular [31.8%]) were included. Inclusion criteria consisted of treatment with a uniform therapy scheme and continuous aftercare in the same institution. Initial diagnosis was between 1975-1995 (age at diagnosis, 14-84 years, median, 49.7). Tumor stage: pT1, n = 92; pT2, 211; pT3, 58; pT4, 123. Low-risk:or=pT3 NX M0, 331; high-risk pT4 and/or M1, 153. After thyroidectomy…

A comparative analysis of striatal and extrastriatal D2/D3 binding of five pharmacologically different “atypical” antipsychotics

Acute Vestibular Nucleus Lesion Affects Cortical Activation Pattern during Caloric Irrigation in PET

Medial Vestibular Nucleus Lesions in Wallenberg's Syndrome Cause Decreased Activity of the Contralateral Vestibular Cortex

Three patients with the clinical diagnosis of Wallenberg's syndrome caused by acute unilateral ischemic infarctions, which included the vestibular nucleus in the medullary brain stem and afferent vestibular pathways, were examined by positron emission tomography (PET) during caloric vestibular stimulation. They all had typical signs of vestibular dysfunction such as transient rotatory vertigo with vomiting at the onset, ipsiversive body and ocular lateropulsion, and a complete ocular tilt reaction with tilts of the subjective visual vertical. Compared with healthy volunteers, who show activation in a network of temporoparietal vestibular areas within both hemispheres, especially in the post…

The striatal and extrastriatal D2/D3 receptor-binding profile of clozapine in patients with schizophrenia.

Positron emission tomography (PET) studies reveal that clozapine at clinically used doses occupies less than 60% of D2/D3 dopamine receptors in human striatum. Here, the occupancy of D2/D3 dopamine receptors by clozapine in patients with schizophrenia was determined to test the hypothesis that clozapine binds preferentially to extrastriatal dopamine receptors. A total of 15 clozapine-treated inpatients with schizophrenia underwent a [18F]fallypride PET scan. Receptor occupancy was calculated as percent reduction in binding potential relative to unblocked values measured in seven normal volunteers. Mean D2/D3 receptor occupancy was statistically significantly higher in cortical (inferior tem…

High-Risk Patients with Differentiated Thyroid Cancer T4 Primary Tumors Achieve Remnant Ablation Equally Well Using rhTSH or Thyroid Hormone Withdrawal

Few data exist on using thyrotropin alfa (recombinant human thyroid-stimulating hormone [rhTSH]) with radioiodine for thyroid remnant ablation of patients who have T4 primary tumors (invasion beyond the thyroid capsule).A retrospective chart review protocol at nine centers in Europe was set up with special waiver of need for informed consent, along with a careful procedure to avoid selection bias when enrolling patients into the database. Data on 144 eligible patients with T4 tumors were collected (T4, N0-1, M0-1; mean age 49.7 years; 65% female; 88% papillary cancer). All had received (131)I remnant ablation following TSH stimulation with rhTSH or thyroid hormone withdrawal (THW) since Jan…

Prospective Evaluation of Positron Emission Tomography in the Preoperative Staging of Esophageal Carcinoma

Hypothesis Positron emission tomography (PET) is a useful tool in the selection of patients with esophageal cancer who may not benefit from esophageal resection. Design Case series. Setting Tertiary care hospital. Patients Eighty-one patients with newly diagnosed esophageal cancer who underwent PET and computer tomography (CT) of the chest and abdomen (and of the neck in 45 patients) within 45 days were included. Main Outcome Measures We calculated the sensitivity and specificity in detecting metastatic sites on the basis of 31 histologically verified lesions. In addition to results obtained on CT, the information provided by PET was evaluated with a view to the choice of management strateg…

In vivo imaging of dopamine receptors in a model of temporal lobe epilepsy

Alterations in dopamine neurotransmission in animal models of epilepsies have been frequently demonstrated using invasive neuroscience or ex vivo techniques. We aimed to test whether corresponding alterations could be detected by noninvasive in vivo brain imaging with positron emission tomography (PET) in the chronic phase of the rat pilocarpine model of temporal lobe epilepsy.Six pilocarpine-treated Wistar rats exhibiting spontaneous recurrent seizures and nine control rats were studied with PET using [(18)F]-fallypride, a high-affinity dopamine D(2/3) receptor ligand. Parametric images of [(18)F]-fallypride specific binding were calculated using a reference tissue method, and the two grou…

Radiation response non-invasively imaged by [18F]FDG-PET predicts local tumor control and survival in advanced oral squamous cell carcinoma

It is a major challenge to preoperatively identify patients who will profit from surgery of advanced oral cancer. In multimodality therapy, response to neoadjuvant radiation correlates to treatment success. Hence, for preoperative decisions, assessment of treatment response is required. Therefore, we analysed the prognostic significance of glucose metabolism after preoperative radiotherapy. [(18)F]FDG-PET investigations were performed for re-staging 35 patients after neoadjuvant radiotherapy (36Gy) immediately prior to tumor resection. Emission and transmission measurements were obtained and SUV's were calculated for the sites of maximum [(18)F]FDG-uptake. Subpopulations of "low" (SUV4) and…

Validating the DemTect with 18-Fluoro-2-Deoxy-Glucose Positron Emission Tomography as a Sensitive Neuropsychological Screening Test for Early Alzheimer Disease in Patients of a Memory Clinic

<i>Objectives:</i> The first study to validate the diagnostic value of the DemTect, a short neuropsychological screening test for dementia (8–10 min), using 18-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) in patients of a memory clinic. <i>Methods:</i> DemTect results were compared to the clinical diagnosis and to FDG-PET as a reference method for the early in vivo detection of Alzheimer’s disease (AD). <i>Results:</i> 38 patients (age 65.2 ± 9.8 years, 16 men, 22 women) were investigated using clinical standard examination, FDG-PET, and cranial magnetic resonance imaging. According to NINCDS-ADRDA and Petersen’s criteria, 18 patients had…

Dopamine in amygdala gates limbic processing of aversive stimuli in humans

Dopamine is known to contribute to the amygdala-mediated aversive response, where increased dopamine release can augment amygdala function. Combining fMRI and PET imaging techniques, Kienast et al. present findings that suggest a functional link between anxiety temperament, dopamine storage capacity and emotional processing in the amygdala. Dopamine is released under stress and modulates processing of aversive stimuli. We found that dopamine storage capacity in human amygdala, measured with 6-[18F]fluoro-L-DOPA positron emission tomography, was positively correlated with functional magnetic resonance imaging blood oxygen level–dependent signal changes in amygdala and dorsal anterior cingula…

PET Studies of Net Blood—Brain Clearance of FDOPA to Human Brain: Age-Dependent Decline of [18F]Fluorodopamine Storage Capacity

Conventional methods for the graphical analysis of 6-[18F]fluorodopa (FDOPA)/positron emission tomography (PET) recordings ( Kappin) may be prone to negative bias because of oversubtraction of the precursor pool in the region of interest, and because of diffusion of decarboxylated FDOPA metabolites from the brain. These effects may reduce the sensitivity of FDOPA/PET for the detection of age-related changes in dopamine innervations. To test for these biasing effects, we have used a constrained compartmental analysis to calculate the brain concentrations of the plasma metabolite 3- O-methyl-FDOPA (OMFD) during 120 mins of FDOPA circulation in healthy young, healthy elderly, and Parkinson's …

Sympathetic activity at rest and motor brain areas: FDG-PET study.

Although recent studies identified brain areas which are involved in short term activation of the sympathetic nervous system, little is known about brain mechanisms which generate the individual variability of basal autonomic activity. In this fluorodeoxyglucose positron emission tomography study (FDG-PET), we aimed to identify brain regions, which covary with function parameters of the autonomic nervous system at rest. Therefore, FDG-PET (Siemens, Germany) was performed twice in 14 healthy resting subjects (7 m, 7 f; mean age 29.5 years) while different parameters of autonomic function were assessed simultaneously: Blood pressure, heart rate, power spectra of heart rate variability (HF/LF …

Elevated [18F]FDOPA utilization in the periaqueductal gray and medial nucleus accumbens of patients with early Parkinson's disease

Udgivelsesdato: 2010-Feb-15 PET studies with the DOPA decarboxylase substrate 6-[(18)F]fluoro-l-DOPA (FDOPA) reveal the storage of [(18)F]-fluorodopamine within synaptic vesicles, mainly of dopamine fibres. As such, FDOPA PET is a sensitive indicator of the integrity of the nigrostriatal dopamine innervation. Nonetheless, there have been several reports of focal elevations of FDOPA utilization in brain of patients with Parkinson's disease (PD), all based on reference tissue methods. To investigate this phenomenon further, we used voxel-wise steady-state kinetic analysis to search for regions of elevated FDOPA utilization (K; ml g(-1) min(-1)) and steady-state trapping (V(d); ml g(-1)) in a …

Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge

Summary Objective To verify findings of an independently regulated anterior limbic alpha band source. Methods In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t -statistical parametric mapping [SPM{ t }]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. Results Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18,…

High opiate receptor binding potential in the human lateral pain system

To determine how opiate receptor distribution is co-localized with the distribution of nociceptive areas in the human brain, eleven male healthy volunteers underwent one PET scan with the subtype-nonselective opioidergic radioligand [(18)F]fluoroethyl-diprenorphine under resting conditions. The binding potential (BP), a parameter for the regional cerebral opioid receptor availability, was computed using the occipital cortex as reference region. The following regions of interest (ROIs) were defined on individual MR images: thalamus, sensory motor strip (SI/MI area), frontal operculum, parietal operculum, anterior insular cortex, posterior insular cortex, anterior cingulate cortex (ACC; peri-…

Positronen-Emissions-Tomographie zum präoperativen Staging des Ösophaguskarzinoms

BACKGROUND AND OBJECTIVE Exact preoperative staging is a prerequisite for the indication as well as the choice of the appropriate operative technique for patients with esophageal carcinoma. In this prospective study we assessed whether positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) increases the accuracy of staging compared to standard computer tomography (CT) and leads to a different therapeutic approach. PATIENTS AND METHODS 30 patients (25 men, 5 women, median age 63 years) with histologically identified carcinoma of the esophagus (n =29) and the cardia (n = 1), respectively, were studied. All patients underwent FDG-PET imaging of the neck, chest, and abdomen as w…

Opioid receptor PET reveals the psychobiologic correlates of reward processing.

Little is known about the neurobiologic correlates of human personality. On the basis of the key role of the central opioidergic system in addiction and substance abuse, we investigated the relationship between certain personality traits that are supposed to be relevant in addiction and the opioid receptor status in healthy subjects.We investigated 23 healthy male volunteers who were extensively clinically tested to exclude substance abuse. All of the subjects underwent 1 PET scan with the subtype-nonselective opioidergic radioligand 18F-fluoroethyl-diprenorphine under resting conditions without sensory or cognitive stimulation. Subsequently, the subjects were psychologically tested for the…

Influence of cell proportions and proliferation rates on FDG uptake in squamous-cell esophageal carcinoma: a PET study.

We investigated the influence of cell proportions and proliferation activities on tumor maximum standard uptake value (SUV(max)) in patients with squamous-cell esophageal cancer (SCEC).Sixteen (16) patients with untreated SCEC were examined with (18)F-flourodeoxyglucose positron emission tomography (FDG-PET). The tumor SUV(max) were calculated. Tumors were resected by transthoracic esophagectomy. Tissues were stained with hematoxylin and eosin for the measurement of cell proportions and MIB-1 for measurement of proliferation indices (PIs). Tumor SUV and histologic data were related by using multiple linear regression analysis.The mean proportion of tumor cells in the tumor site was 58.1% (+…

The unpleasantness of tonic pain is encoded by the insular cortex

Objective: Muscle pain differs from skin pain with respect to quality, accuracy of localization, and unpleasantness. This study was conducted to identify the brain regions associated with the affective-motivational component of tonic skin and muscle pain. Methods: Forty healthy volunteers were investigated in three groups with different F-18 fluorodeoxyglucose PET activation scans. A verbal rating scale (VRS) was used to quantify pain intensity and unpleasantness. One group was investigated during painful infusion of an acidified phosphate buffer (pH 5.2) into either muscle or skin for 30 minutes. Muscle and skin infusions were adjusted to achieve pain intensity rating of VRS = 40. The seco…

Functional Plasticity after Unilateral Vestibular Midbrain Infarction in Human Positron Emission Tomography.

The aim of the study was to uncover mechanisms of central compensation of vestibular function at brainstem, cerebellar, and cortical levels in patients with acute unilateral midbrain infarctions presenting with an acute vestibular tone imbalance. Eight out of 17 patients with unilateral midbrain infarctions were selected on the basis of signs of a vestibular tone imbalance, e.g., graviceptive (tilts of perceived verticality) and oculomotor dysfunction (skew deviation, ocular torsion) in F18-fluordeoxyglucose (FDG)-PET at two time points: A) in the acute stage, and B) after recovery 6 months later. Lesion-behavior mapping analyses with MRI verified the exact structural lesion sites. Group su…

In vivo molecular and morphological imaging by real time confocal mini-microscopy

We evaluated a newly developed miniaturized confocal laser microscopy probe for real-time in vivo molecular and morphological imaging of normal, inflammatory, and malignant tissue in rodents. In the rigid mini-microscopy probe (diameter 7 mm), a single line laser delivers an excitation wavelength of 488 nm. Optical slice thickness is 7 μm, lateral resolution 0.7 μm. The range of the z-axis is 0 - 250 μm below the tissue surface. Organ systems were examined in vivo in rodent models of human diseases. FITC-labeled Lycopersion esculentum lectin was injected or selected cell populations stained for molecular targeting. Morphological imaging was performed using fluorescein sodium, FITC-labeled d…

Thalamic infarctions cause side-specific suppression of vestibular cortex activations.

H2O15-PET was performed during caloric vestibular stimulation of the right and left external ears in eight right-handed patients with acute unilateral infarctions or haemorrhages of the posterolateral thalamus (four right, four left). The posterolateral thalamus is the relay station for ipsi- and contralateral ascending vestibular input to the multiple multisensory vestibular cortex areas. The aim of this study was to evaluate the differential effects of unilateral vestibular thalamic lesions on thalamo-cortical projections, right hemispheric dominance and reciprocal inhibitory visual-vestibular interaction, as well as perceptual and ocular motor consequences during caloric irrigation. The …

Striatal and extrastriatal D2/D3-receptor-binding properties of ziprasidone: a positron emission tomography study with [18F]Fallypride and [11C]raclopride (D2/D3-receptor occupancy of ziprasidone).

To elucidate the Batypicality( of ziprasidone, its striatal and extrastriatal D2/D3-receptor binding was characterized in patients with schizophrenia under steady-state conditions. These data were compared with striatal receptor occupancy values after single-dose ziprasidone ingestion in healthy controls. ( 18 F)fallypride positron emission tomography (PET) recordings were obtained in 15 patients under steady-state ziprasidone treatment at varying time points after the last dose. Binding potentials were calculated for striatal and extrastriatal regions. D2/D3-receptor occupancies were expressed relative to binding potentials in 8 unmedicated patients. In a parallel ( 11 C)raclopride-PET stu…

The applicability of SRTM in [18F]fallypride PET investigations: Impact of scan durations

The high-affinity radioligand [18F]fallypride (FP) is frequently used for quantification of striatal/extrastriatal D2/3 receptors and the receptor occupancies of antipsychotics (APs). Its 110 minutes half-life allows long scan durations. However, the optimum scan duration is a matter of debate. This investigation focuses on scan-duration-related effects on simplified reference tissue model (SRTM) results and the time point of transient equilibrium in a large sample of dynamic FP positron emission tomography (PET) scans. Fifty drug-free and 50 AP-treated subjects underwent FP-PET scans (180 minutes scan duration). The binding potential ( BPND) of the putamen, thalamus, and temporal cortex w…

[ 18 F]Fluoroethylflumazenil: a novel tracer for PET imaging of human benzodiazepine receptors

5-(2'-[18F]Fluoroethyl)flumazenil ([18F]FEF) is a fluorine-18 labelled positron emission tomography (PET) tracer for central benzodiazepine receptors. Compared with the established [11C]flumazenil, it has the advantage of the longer half-life of the fluorine-18 label. After optimisation of its synthesis and determination of its in vitro receptor affinities, we performed first PET studies in humans. PET studies in seven healthy human volunteers were performed on a Siemens ECAT EXACT whole-body scanner after injection of 100-280 MBq [L8F]FEF. In two subjects, a second PET scan was conducted after pretreatment with unlabelled flumazenil (1 mg or 2.5 mg i.v., 3 min before tracer injection). A t…

Association of elevated phospho-tau levels with alzheimer-typical 18F-Fluoro-2-Deoxy-D-Glucose positron emission tomography findings in patients with mild cognitive impairment

Abstract Background Mild cognitive impairment is considered to be a transitional stage between normal aging and dementia. Phosphorylated tau protein in cerebrospinal fluid and even more decrements of cerebral glucose metabolism in parietal, temporal, or cingulate regions have shown favorable specificity for the diagnosis of Alzheimer dementia and could be useful supplementary tools to determine Alzheimer pathology in early stages. Methods We measured cerebrospinal fluid tau phosphorylated at threonine 181 protein, cerebrospinal fluid total tau, and cerebral glucose metabolism using 18F-fluoro-2-deoxy-D-glucose positron emission tomography in 16 patients with mild cognitive impairment and ag…

Synthesis and preliminary evaluation of (R,R)(S,S) 5-(2-(2-[4-(2-[18F]fluoroethoxy)phenyl]-1-methylethylamino)-1-hydroxyethyl)-benzene-1,3-diol ([18F]FEFE) for the in vivo visualisation and quantification of the β2-adrenergic receptor status in lung

The 18 F-labeled b2-adrenergic receptor ligand (R,R)(S,S) 5-(2-(2-(4-(2-( 18 F)fluoroethoxy)phenyl)-1-methylethylamino)-1- hydroxyethyl)-benzene-1,3-diol, a derivative of the original highly selective racemic fenoterol, was synthesized in an overall radio- chemical yield of 20% after 65 min with a radiochemical purity higher than 98%. The specific activity was in the range of 50-60 GBq/mmol. In vitro testing of the non-radioactive fluorinated fenoterol derivative with isolated guinea pig trachea was conducted to obtain an IC50 value of 60 nM. Preliminary ex vivo organ distribution and in vivo experiments with positron emission tomography (PET) on guinea pigs were performed to study the biod…

Cerebrospinal Fluid Tau Protein Levels and <sup>18</sup>F-Fluorodeoxyglucose Positron Emission Tomography in the Differential Diagnosis of Alzheimer’s Disease

<i>Aims:</i> In this study, we aimed to compare cerebrospinal fluid (CSF) levels of total tau (t-tau), phosphorylated tau (p-tau<sub>181</sub>) and positron emission tomography with <sup>18</sup>F-fluorodeoxyglucose (FDG-PET) in the differential diagnosis of Alzheimer’s disease (AD) under clinical conditions. <i>Method:</i> In a cross-sectional, blinded, single-center study, we examined a sample of 75 unselected memory clinic patients with clinical diagnoses of dementia of Alzheimer type (DAT; n = 24), amnestic mild cognitive impairment (MCI; n = 16), other dementias (n = 13) and nondemented controls (n = 22). Discriminative accuracy, sensitiv…

Resting state glucose utilization and the CERAD cognitive battery in patients with Alzheimer's disease

The present study examined the cortical functional representation of neuropsychological domains in Alzheimer's disease (AD) using positron emission tomography (PET) and the neuropsychological assessment battery of the Consortium to Establish a Registry of Alzheimer's Disease (CERAD). Thirty patients with clinical probable AD and 10 elderly healthy controls underwent (18)FDG brain PET imaging during a resting state. Correlations between metabolic values and cognitive measures were determined using a region of interest analysis with NEUROSTAT (University of Michigan, USA) and a voxel-based analysis with SPM96 (Wellcome Department, London, UK). Specific correlations were seen between measures …

Positron Emission Tomography for Staging Esophageal Cancer: Does It Lead to a Different Therapeutic Approach?

Accurate preoperative staging is essential for the indication and selection of the appropriate surgical procedure in patients with esophageal cancer. The present prospective study was designed to determine if the preoperative use of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) increases the accuracy of staging esophageal cancer compared with computed tomography (CT) and if it thereby leads to a different therapeutic approach. A total of 58 patients, 46 men and 12 women (mean age 61 years), with histologic proof of esophageal carcinoma underwent FDG-PET of the neck, chest, and abdomen, as well as CT of the chest and abdomen, to determine tumor stage. FDG-PET and CT data we…

Asymmetry in dopamine D2/3 receptors of caudate nucleus is lost with age

Molecular and functional imaging techniques reveal evidence for lateralization of human cerebral function. Based on animal data, we hypothesized that asymmetry in dopamine neurotransmission declines during normal aging. In order to test this hypothesis, we measured dopamine D2/3 receptor availability with [18F]desmethoxyfallypride-PET (DMFP) in putamen and caudate nucleus (NC) of 21 healthy, right-handed males (24-60 years; 35+/-10). For volumetric analysis, high-resolution T1-weighted MR-images were obtained in 18 of the PET-subjects in order to assess possible age-related decreases in NC and putamen volume. The calculated DMFP binding potentials (BP) showed a right-ward asymmetry in NC of…

SPM-based count normalization provides excellent discrimination of mild Alzheimer's disease and amnestic mild cognitive impairment from healthy aging☆

Statistical comparisons of [(18)F]FDG PET scans between healthy subjects and patients with Alzheimer's disease (AD) or amnestic mild cognitive impairment (aMCI) using Statistical Parametric Mapping (SPM) usually require normalization of regional tracer uptake via ROIs defined using additional software. Here, we validate a simple SPM-based method for count normalization. FDG PET scans of 21 mild, 15 very mild AD, 11 aMCI patients and 15 age-matched controls were analyzed. First, we obtained relative increases in the whole patient sample compared to controls (i.e. areas relatively preserved in patients) with proportional scaling to the cerebral global mean (CGM). Next, average absolute counts…

P1‐107: Positive effects of a 6‐month stage‐specific cognitive intervention program on brain metabolism in subjects with amnestic mild cognitive impairment (aMCI) and mild Alzheimer's Disease (AD)

Net influx of plasma 6-[18F]fluoro-L-DOPA (FDOPA) to the ventral striatum correlates with prefrontal processing of affective stimuli.

Dopaminergic neurotransmission in the ventral and dorsal striatum interact with central processing of rewarding and reward-indicating stimuli, and may affect frontocortical-striatal-thalamic circuits regulating goal-directed behaviour. Thirteen healthy male volunteers were investigated with multimodal imaging, using the radioligand 6-[ 18 F]fluoro-L-DOPA (FDOPA) for positron emission tomography (PET) measurements of dopamine synthesis capacity, and also functional magnetic resonance imaging (fMRI) in a cognitive activation paradigm. We calculated the correlation between FDOPA net blood-brain influx (K app in ; ml/g/min) in the ventral and associative dorsal striatum and BOLD signal changes …

Relationship Between Body Mass Index, ApoE4 Status, and PET-Based Amyloid and Neurodegeneration Markers in Amyloid-Positive Subjects with Normal Cognition or Mild Cognitive Impairment.

Body weight loss in late-life is known to occur at a very early stage of Alzheimer's disease (AD). Apolipoprotein E4 (ApoE4) represents a major genetic risk factor for AD and is linked to an increased cortical amyloid-β (Aβ) accumulation. Since the relationship between body weight, ApoE4, and AD pathology is poorly investigated, we aimed to evaluate whether ApoE4 allelic status modifies the association of body mass index (BMI) with markers of AD pathology. A total of 368 Aβ-positive cognitively healthy or mild cognitive impaired subjects had undergone [18F]-AV45-PET, [18F]-FDG-PET, and T1w-MRI examinations. Composite cortical [18F]-AV45 uptake and [18F]-FDG uptake in posterior cingulate cor…

Modulation of [18F]fluorodopa (FDOPA) kinetics in the brain of healthy volunteers after acute haloperidol challenge.

In animal studies, acute antipsychotic treatment was shown to enhance striatal DOPA-decarboxylase (DDC) activity. However, this phenomenon has not been demonstrated in humans by positron emission tomography (PET). Therefore, we investigated acute haloperidol effects on DDC activity in humans using [18F]fluorodopa (FDOPA) PET. Nine healthy volunteers were scanned with FDOPA in drug-free baseline conditions and after 3 days of haloperidol treatment (5 mg/day). A continuous performance test (CPT) was administered in both conditions. The net blood-brain clearance of FDOPA (K(in)app) in striatum, mesencephalon, and medial prefrontal cortex was calculated by volume-of-interest analysis. The macro…

Reduced Cerebral Fluoro-l-Dopamine Uptake in Adult Patients Suffering from Phenylketonuria

Deficiency of phenylalanine hydroxylase activity in phenylketonuria (PKU) causes an excess of phenylalanine (Phe) throughout the body, predicting impaired synthesis of catecholamines in the brain. To test this hypothesis, we used positron emission tomography (PET) to measure the utilization of 6-[18F]fluoro-l-dopamine (FDOPA) in the brain of adult patients suffering from PKU and in healthy controls. Dynamic 2-h long FDOPA emission recordings were obtained in seven adult PKU patients (five females, two males; age: 21 to 27 years) with elevated serum Phe levels, but lacking neurologic deficits. Seven age-matched, healthy volunteers were imaged under identical conditions. The utilization of F…

Die Positronenemissionstomographie zur pr�operativen Lymphknotendiagnostik bei �sophaguskarzinom

Vorraussetzung fur Indikation und Wahl des geeigneten operativen Verfahrens bei Patienten mit Osophaguskarzinom ist ein genaues praoperatives Staging. Ziel der prospektiven Studie war es, zu klaren, ob eine Positronenemissionstomographie mit 18F-Fluoro-Deoxyglukose (FDG-PET) die Genauigkeit des praoperativen Lymphknotendiagnostik gegenuber der Computertomographie (CT) erhoht und die Wahl des operativen Zugangs zur Osophagusresektion beeinflusst. 58 Patienten, 46 Manner und 12 Frauen (Alter 61 Jahre im Mittel), erhielten bei histologisch gesichertem Osophaguskarzinom im Rahmen des Stagings ein FDG-PET von Hals, Thorax und Abdomen sowie ein CT von Thorax und Abdomen. Sensitivitat, Spezifitat …

A Knowledge-Based System for the Diagnosis of Alzheimer’s Disease

Therapies to slow down the progression of Alzheimer’s disease are most effective when applied in its initial stages. Therefore it is important to develop methods to diagnose the disease as early as possible. It is also desirable to establish standards which can be used generally by physicians who may not be experts in diagnosis of the disease. One possible method to obtain an early diagnosis is the evaluation of the glucose metabolism of the brain. In this paper we present a prototype of an expert system that automatically diagnoses Alzheimer’s disease on the basis of positron emission tomography images displaying the metabolic activity in the brain.

FDG-PET mapping the brain substrates of visuo-constructive processing in Alzheimer´s disease

The anatomical basis of visuo-constructive impairment in AD is widely unexplored. FDG-PET can be used to determine functional neuronal networks underlying specific cognitive performance in the human brain. In the present study, we determined the pattern of cortical metabolism that was associated with visuo-constructive performance in AD. We employed two widely used visuo-constructive tests that differ in their demand on visual perception and processing capacity. Resting state FDG-PET scans were obtained in 29 probable AD patients, and cognitive tests were administered. We made a voxel-based regression analysis of FDG uptake to scores in visual test performance, using the SPM5 software. Perf…

High striatal occupancy of D2-like dopamine receptors by amisulpride in the brain of patients with schizophrenia.

The 'atypicality' of the antipsychotic drug, amisulpride, has been attributed to preferential extrastriatal binding. Previous investigations of striatal D2 receptor occupancy by amisulpride revealed conflicting results. The aim of this PET study was to measure the striatal occupancy by amisulpride and to correlate it with the corresponding drug plasma concentrations. Nine amisulpride-treated patients and 12 healthy volunteers serving as controls were studied with PET and [18F]desmethoxyfallypride. Occupancy values and plasma concentrations were nonlinearly fitted to an E max model. Results showed 43-85% (putamen) and 67-90% (caudate) D2-like receptor occupancy. Plasma amisulpride concentrat…

Preserved visual-vestibular interaction in patients with bilateral vestibular failure

Background: During caloric vestibular stimulation, subjects showed bilateral activation of the vestibular cortex in the posterior insula and retroinsular region as well as concurrent deactivation of visual cortex areas bilaterally. This finding was the basis for the concept of a reciprocal inhibitory interaction between the vestibular and the visual systems. Objective: To analyze the modulations of this activation and deactivation pattern in patients with loss of vestibular input, that is, in patients with bilateral vestibular failure (BVF). Methods: Modulations of regional cerebral blood flow (rCBF) in PET were measured in nine patients with BVF and compared with those in healthy volunteer…

Acute Alcohol Effects on Neuronal and Attentional Processing: Striatal Reward System and Inhibitory Sensory Interactions under Acute Ethanol Challenge

The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological t…

FDG-PET and CSF phospho-tau for prediction of cognitive decline in mild cognitive impairment

Specific patterns of cortical glucose metabolism disturbances and increased CSF phospho-tau (p-tau(181)) concentrations could be demonstrated to predict cognitive decline and shift to dementia in amnestic mild cognitive impairment (MCI). But comparisons of both diagnostic tools have not been undertaken so far. The aim of the study was to compare (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) findings and CSF phospho-tau (p-tau(181)) measurements in the prediction of cognitive deterioration and conversion to dementia in MCI. During follow-up (mean 19 months) eight of 16 patients (50%) showed progressive cognitive decline, and four patients shifted to dementia. Patholog…

SPET/CT image co-registration in the abdomen with a simple and cost-effective tool

Fusion of morphology and function has been shown to improve diagnostic accuracy in many clinical circumstances. Taking this into account, a number of instruments combining computed tomography (CT) with positron emission tomography (PET) or single-photon emission tomography (SPET) are appearing on the market. The aim of this study was to evaluate a simple and cost-effective approach to generate fusion images of similar quality. For the evaluation of the proposed approach, patients with neuroendocrine abdominal tumours with liver metastases were chosen, since the exact superimposition in the abdomen is more difficult than in other regions. Five hours following the injection of 110 MBq (111)In…

High opiate receptor binding potential in the human lateral pain system: A (FEDPN)PET study

Dopamine D2/D3 receptor availability and venturesomeness.

The construct of impulsivity is considered as a major trait of personality. There is growing evidence that the mesolimbic dopamine system plays an important role in the modulation of impulsivity and venturesomeness, the two key components within the impulsivity-construct. The aim of the present study was to explore an association between trait impulsivity measured with self-assessment and the dopaminergic neurotransmission as measured by positron emission tomography (PET) in a cohort of healthy male subjects. In vivo D2/D3 receptor availability was determined with [(18)F]fallypride PET in 18 non-smoking healthy subjects. The character trait impulsivity was measured using the Impulsiveness-V…

Imaging correlates of behavioral impairments: An experimental PET study in the rat pilocarpine epilepsy model

Abstract Psychiatric comorbidities are prevalent in patients with epilepsy and greatly contribute to the overall burden of disease. The availability of reliable biomarkers to diagnose epilepsy-associated comorbidities would allow for effective treatment and improved disease management. Due to their non-invasive nature, molecular imaging techniques such as positron emission tomography (PET) are ideal tools to measure pathologic changes. In the current study we investigated the potential of [18F]fluoro-2-deoxy- d -glucose ([18F]FDG) and 2′-methoxyphenyl-(N-2′-pyridinyl)-p-18F-fluoro-benzamidoethylpiperazine ([18F]MPPF) as imaging correlates of neurobehavioral comorbidities in the pilocarpine …

Baseline [18F]-FDOPA kinetics are predictive of haloperidol-induced changes in dopamine turnover and cognitive performance: A positron emission tomography study in healthy subjects.

The telencephalic dopamine innervations contribute to the modulation of cognitive processing. However, the relationship between cognitive effects of D(2/3)-receptor antagonism and dopamine transmission is not described in healthy subjects. We therefore tested effects of acute haloperidol (5 mg/d over 3 days) on continuous performance task (CPT) performance and 6-[(18)F]-fluoro-l-DOPA (FDOPA) PET parameters. Nine physically and mentally healthy male men performed two FDOPA-PET scans including arterial plasma withdrawal. Over 3 days before the second scan, all subjects were treated with 5 mg/d haloperidol orally. Using our novel steady-state analysis, we calculated the intrinsic rate of the c…

Three Determinants of Vestibular Hemispheric Dominance during Caloric Stimulation: A Positron Emission Tomography Study

Corrigendum to “The thalamus as the generator and modulator of EEG alpha rhythm: A combined PET/EEG study with lorazepam challenge in humans” [NeuroImage 22 (2004) 637–644]

Department of Psychiatry, Johannes Gutenberg–University Mainz, 55131 Mainz, GermanyAvailable online 2 May 20061053-8119/$ - see front matter D 2006 Elsevier Inc. All rights reserved.doi:10.1016/j.neuroimage.2006.03.007DOI of original article:10.1016/j.neuroimage.2004.01.047.* Corresponding author. Department of Nuclear Medicine, Johannes Gutenberg–University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany. Fax: +496131 17 2448.E-mail address: schreckenberger@nuklear.klinik.uni-mainz.de (M. Schreckenberger).Available online on ScienceDirect (www.sciencedirect.com).

Subchronic haloperidol downregulates dopamine synthesis capacity in the brain of schizophrenic patients in vivo

Udgivelsesdato: 2003-Apr The antipsychotic effect of neuroleptics cannot be attributed entirely to acute blockade of postsynaptic D(2)-like dopamine (DA) receptors, but may arise in conjunction with the delayed depolarization block of the presynaptic neurons and reduced DA synthesis capacity. Whereas the phenomenon of depolarization block is well established in animals, it is unknown if a similar phenomenon occurs in humans treated with neuroleptics. We hypothesized that haloperidol treatment should result in decreased DA synthesis capacity. We used 6-[(18)F]fluoro-L-dopa (FDOPA) and positron emission tomography (PET) in conjunction with compartmental modeling to measure the relative activi…

A fronto-parietal network is mediating improvement of motor function related to repetitive peripheral magnetic stimulation: A PET-H2O15 study.

Repetitive peripheral magnetic stimulation (RPMS) is a focused and painless stimulation method, in which muscle contractions are elicited by depolarization of the terminal motor branches. Clinical-experimental investigations on different disorders of sensorimotor integration in the last decade have shown that RPMS can be used for the rehabilitation of motor functions after stroke. It is supposed that this therapeutic effect is based on the RPMS-induced proprioceptive inflow to the CNS. To analyze the conditioning effects of RPMS on reorganization of the motor system on cortical level positron emission tomography (PET) is used. Regional cerebral blood flow (rCBF) has been measured using H(2)…

Imaging biomarkers of behavioral impairments: A pilot micro-positron emission tomographic study in a rat electrical post-status epilepticus model.

Objective In patients with epilepsy, psychiatric comorbidities can significantly affect the disease course and quality of life. Detecting and recognizing these comorbidities is central in determining an optimal treatment plan. One promising tool in detecting biomarkers for psychiatric comorbidities in epilepsy is positron emission tomography (PET). Methods Results Behavioral and biochemical variables were cross-correlated with the results from two mu PET scans using the tracers [F-18]fluoro-2-deoxy-D-glucose ([F-18]FDG) and 2 '-methoxyphenyl-(N-2 '-pyridinyl)-p-F-18-fluoro-benzamidoethylpiperazine ([F-18]MPPF) to explore potential biomarkers for neurobehavioral comorbidities in an electrica…

Synthesis and in Vitro Evaluation of Biotinylated RG108:  A High Affinity Compound for Studying Binding Interactions with Human DNA Methyltransferases

Small-molecule inhibitors of DNA methyltransferases such as RG108 represent promising candidates for cancer drug development. We report the synthesis and in vitro analysis of a biotinylated RG108 conjugate, 2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-3-(5-[3-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)pentanoylamino]propoxy]-1H-indol-3-yl)propionic acid (bio-RG108), for the evaluation of interactions with DNA methyltransferase enzymes. The structural design of the chemically modified inhibitor was aided by molecular modeling, which suggested the possibility for extensive chemical modifications at the 5-position of the tryptophan moiety in RG108. The inhibitory activity of the corresponding d…

Human dopamine receptor D2/D3 availability predicts amygdala reactivity to unpleasant stimuli

r r Abstract: Dopamine (DA) modulates the response of the amygdala. However, the relation between dopa- minergic neurotransmission in striatal and extrastriatal brain regions and amygdala reactivity to affective stimuli has not yet been established. To address this issue, we measured DA D2/D3 receptor (DRD2/3) availability in twenty-eight healthy men (nicotine-dependent smokers and never-smokers) using positron emission tomography with ( 18 F)fallypride. In the same group of participants, amygdala response to unpleasant visual stimuli was determined using blood oxygen level-dependent (BOLD) functional mag- netic resonance imaging. The effects of DRD2/3 availability in emotion-related brain …

Age-dependent decline of steady state dopamine storage capacity of human brain: an FDOPA PET study.

Conventional indices of the utilization of FDOPA in living human brain have not consistently revealed important declines in dopamine function with normal aging. However, most methods of kinetic analysis have assumed irreversible trapping of decarboxylated FDOPA metabolites in brain, an assumption that is violated even in PET recordings of short duration. Therefore, we have developed methods for the calculation of steady-state storage of FDOPA together with its decarboxylated metabolites (V(d), mlg(-1)), based upon improved kinetic analysis of 120-min emission recordings. In a group of 28 normal male subjects, of age ranging from 23 to 73 years, the magnitude of V(d) in the striatum and in e…

18F-labeling of peptides by means of an organosilicon-based fluoride acceptor.

Fluorine-18 is among the most commonly used radionuclides for positron emission tomography (PET). This non-invasive imaging technique is capable of providing in vivo information about the distribution of radiolabeled biomolecules by 1808 coincidence detection of two simultaneously emitted photons from positron–electron annihilation. Although a number of different radiotracers have been successfully employed in PET, only a few, such as 2-[F]fluoro-2-deoxy-d-glucose (FDG) and [F]fluorodopa, have gained widespread application in nuclear medicine. The reason for this is that the regioselective introduction of F into tracer molecules is often non-specific and radiochemical yields (RCY) of the Fl…

'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET investigation.

Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron‐emission‐tomography (PET) studies, net blood‐brain clearance of [(18)F]‐fluoro‐l‐DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood‐brain clearance of FDOPA (K [Formula: see text]) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes‐of‐interest. The Wisconsin‐Card‐Sorting‐Test (WCST), Stroop‐T…

6-18F-Fluoro-l-Dihydroxyphenylalanine Positron Emission Tomography Is Superior to123I-Metaiodobenzyl-Guanidine Scintigraphy in the Detection of Extraadrenal and Hereditary Pheochromocytomas and Paragangliomas: Correlation with Vesicular Monoamine Transporter Expression

Context: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) may be better detected by 18F-fluorodihydroxyphenylalanine-positron emission tomography (FDOPA-PET) than 123I-metaiodobenzyl-guanidine (123-I-MIBG) scintigraphy. Objective: The objective of the study was to correlate functional imaging results with immunohistochemical, molecular-genetic, and biochemical findings. Design and Setting: Thirty consecutive patients with suspected PHEO/PGL presenting at a tertiary referral centre were investigated in a prospective study. Patients: Twenty-five patients had confirmed PHEO/PGL. Thirteen of 25 patients had a hereditary PHEO/PGL syndrome (two multiple endocrine neoplasia II, six succinate de…

Ictal functional TCD for the lateralization of the seizure onset zone—a report of two cases

Ictal functional transcranial Doppler sonography (I-fTCD) was used to lateralize the ictal onset zone in the presurgical evaluation of two patients with temporal lobe epilepsy. In one patient, I-fTCD and ictal SPECT were performed simultaneously during EEG-monitoring. In both patients, results were concordant with the ictal SPECT findings, PET and semiology. I-fTCD seems to be an interesting new method to non-invasively lateralize the seizure onset zone with high temporal resolution. I-fTCD and SPECT may give complementary information to lateralize the seizure onset zone.

18F-Markierung von Peptiden mithilfe eines Organosilicium-Fluoridacceptors

Metabolic changes in vestibular and visual cortices in acute vestibular neuritis

Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…

Small animal tumour imaging with MRI and the ECAT EXACT scanner: application of partial volume correction and comparison with microPET data.

Objective Partial volume effects caused by limited spatial resolution of conventional positron emission tomography (PET) scanners result in an underestimation of the activity concentration in small tumours. The aim of the study was to evaluate the feasibility of small animal tumour imaging with the clinical PET scanner ECAT EXACT after partial volume correction based on MRI calculations. The same tumour model was examined additionally with the small animal PET system, microPET focus 120. Methods Before the ECAT EXACT studies recovery coefficients for different sphere volumes were generated with phantom experiments. For the following in-vivo study DS-sarcoma cells were implanted on both hind…

Klinische Relevanz von PET-Untersuchungen in der Neurologie und Psychiatrie

Die Positronenemissionstomographie (PET) ist auf internationaler Ebene inzwischen in der Diagnostik zerebraler Erkrankungen als klinische Routinediagnostik akzeptiert. Das vorrangig klinisch angewandte Radiopharmakon ist die 18F-Fluor- Deoxyglukose (FDG), die die Darstellung des regionalen zerebralen Glukosemetabolismus ermoglicht. Daneben gewinnen markierte Aminosauren und Radiopharmaka, die Rezeptorsysteme und andere komplexe biochemische Vorgange des zentralen Nervensystems darstellen, zunehmend an Bedeutung. Klinisch sinnvolle Anwendungen der Positronenemissionstomographie finden sich vor allem in der Diagnostik dementieller Syndrome, bei Basalganglienerkrankungen sowie bei Fragestellun…

Synthesis of C1-[18F]fluoroethylamnino asparagine for imaging cancer

C1-[18F]fluoroethylamino asparagine was synthesised from N1-t-boc C1-p-nitrophenol asparagine and the radiolabelled precursor [18F]flouroethylamine in a one-pot-synthesis. The yield of this synthesis was 22% referring to [18F]fluoride, including the removal of the protection groups. The in vivo tests are in progress.

Association of Low Striatal Dopamine D2Receptor Availability With Nicotine Dependence Similar to That Seen With Other Drugs of Abuse

All drugs of abuse induce a phasic dopamine release within the striatum that does not undergo habituation. Prolonged substance consumption impairs the natural function of the mesolimbic dopamine system, as shown by a decrease in the availability of striatal dopamine 2 (D(2)) receptors in patients suffering from cocaine, heroin, amphetamine, and alcohol dependence. However, it is unclear whether similar changes can also be observed in heavy-smoking nicotine-dependent smokers.In vivo D(2)/D(3) receptor availability was determined with [ (18)F]fallypride positron emission tomography in 17 heavy-smoking nicotine-dependent subjects and in 21 age-matched never-smoking comparison subjects. The smo…

Central activation by histamine-induced itch: analogies to pain processing: a correlational analysis of O-15 H2O positron emission tomography studies

The aim of this study was to identify the functional cerebral network involved in the central processing of itch and to detect analogies and differences to previously identified cerebral activation patterns triggered by painful noxious stimuli. Repeated positron emission tomography regional cerebral blood flow (rCBF) measurements using O15-labeled water were performed in six healthy right-handed male subjects (mean age 32 +/- 2 years). Each subject underwent 12 sequential rCBF measurements. In all subjects a standardized skin prick test was performed on the right forearm 2 min before each rCBF measurement. For activation, histamine was applied in nine tests in logarithmically increasing con…

Dopamine-modulated aversive emotion processing fails in alcohol-dependent patients.

Negative mood states after alco- hol detoxifi cation may enhance the relapse risk. As recently shown in healthy volunteers, dopamine storage capacity ( V d ) in the left amy- gdala was positively correlated with functional activation in the left amygdala and anterior cin- gulate cortex (ACC) during an emotional task; high functional connectivity between the amy- gdala and the ACC, a region important for emo- tion regulation, was associated with low trait anxiety. Based on these fi ndings, we now tested whether detoxifi ed alcohol-dependent patients have a disrupted modulation of the anterior cin- gulate cortex activation in response to aversive stimuli by amygdala dopamine. Furthermore, we …

P13. Compensation processes for central vestibular dysfunction in patients with acute medullary infarctions (FDG-PET study)

In-vivo confocal real-time mini-microscopy in animal models of human inflammatory and neoplastic diseases

Background and study aims Although various improvements in tissue imaging modalities have recently been achieved, in-vivo molecular and subsurface imaging in the field of gastroenterology remains a technical challenge. In this study we evaluated a newly developed, handheld, miniaturized confocal laser microscopy probe for real-time in-vivo molecular and subsurface imaging in rodent models of human disease. Materials and methods The minimicroscope uses a 488-nm, single line laser for fluorophore excitation. The optical slice thickness is 7 microm, the lateral resolution 0.7 microm. The range of the z-axis is 0-250 microm below the tissue surface. Imaging was performed using different fluores…

18F-fluorodeoxyglucose hypometabolism in cerebellar tonsil and flocculus in downbeat nystagmus.

A patient with downbeat nystagmus was examined by F-fluorodeoxyglucose-positron emission tomography once while off and twice while on successful treatment with 4-aminopyridine. All positron emission tomography scans of the patient showed a reduced cerebral glucose metabolism bilaterally in the region of the cerebellar tonsil and flocculus/paraflocculus when compared with a normal database of the whole brain. An additional region-of-interest analysis revealed that 4-aminopyridine treatment lessened the hypometabolism. This finding supports the hypothesis that the cerebellar tonsil and (para-) flocculus play a crucial role in downbeat nystagmus. The hypometabolism might reflect reduced inhibi…