			Home About us Contact

PET

Distribution by Scientific Domains

Medical Sciences	48%
Polymers and Materials Science	18%
Chemistry	15%
Life Sciences	9%
Engineering	4%
4 Other Domains	6%

Distribution within Medical Sciences

Neurology	18%
Surgery & Surgical Specialties	12%
Oncology & Radiotherapy	6%
Urology	4%
39 Other Subdomains	60%

Kinds of PET

Terms modified by PET

Selected Abstracts

International survey on esophageal cancer: part II staging and neoadjuvant therapy

DISEASES OF THE ESOPHAGUS, Issue 3 2009
J. Boone
SUMMARY The outcome of esophagectomy could be improved by optimal diagnostic strategies leading to adequate preoperative patient selection. Neoadjuvant therapy could improve outcome by increasing the number of radical resections and by controlling metastatic disease. The purposes of this study were to gain insight into the current worldwide practice of staging modalities and neoadjuvant therapy in esophageal cancer, and to detect intercontinental differences. Surgeons with particular interest in esophageal surgery, including members of the International Society for Diseases of the Esophagus, the European Society of Esophagology , Group d'Etude Européen des Maladies de l'Oesophage, and the OESO, were invited to participate in an online questionnaire. Questions were asked regarding staging modalities, neoadjuvant therapy, and response evaluation applied in esophageal cancer patients. Of 567 invited surgeons, 269 participated resulting in a response rate of 47%. The responders currently performing esophagectomies (n= 250; 44%) represented 41 countries across the six continents. Esophagogastroscopy with biopsy and computed tomography (CT) scanning were routinely performed by 98% of responders for diagnosing and staging esophageal cancer, while endoscopic ultrasound (EUS) and barium esophagography were routinely applied by 58% and 51%, respectively. Neoadjuvant therapy is routinely administered by 33% and occasionally by 63% of responders. Of the responders that administer identical neoadjuvant regimens to esophageal adenocarcinoma (AC) and squamous cell carcinoma, 54% favor chemoradiotherapy. For AC, chemotherapy is preferred by 31% of the responders that administer neoadjuvant therapy, whereas for squamous cell carcinoma, the majority of responders (38%) prefer chemoradiotherapy. Response to neoadjuvant therapy is predominantly assessed by CT scanning of the chest and abdomen (86%). Barium esophagography, EUS, and combined CT/PET scan are requested for response monitoring in equal frequency (25%). Substantial differences in applied staging modalities and neoadjuvant regimens were detected between surgeons from different continents. In conclusion, currently the most commonly applied diagnostic modalities for staging and restaging esophageal cancer are CT scanning of the chest and abdomen, gastroscopy, barium esophagography and EUS. Neoadjuvant therapy is routinely applied by one third of the responders. Intercontinental differences have been detected in the diagnostic modalities applied in esophageal cancer staging and in the administration of neoadjuvant therapy. The results of this survey provide baseline data for future research and for the development of international guidelines. [source]

Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA-LDPE and EBAGMA-PET Masterbatches for LDPE/PET Blends

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 3 2010
Aida Benhamida
Abstract The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system. [source]

Melt Mixing of Ethylene/Butyl Acrylate/Glycidyl Methacrylate Terpolymers with LDPE and PET

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 2 2009
Aida Benhamida
Abstract The chemical modification by melt-mixing of an EBAGMA terpolymer with LDPE and PET was investigated with the aim to use these EBAGMA/LDPE and EBAGMA/PET blends (in equal weight quantities) as compatibilizer master batches to improve the compatibility of the LDPE/PET system. It is shown that when the EBAGMA terpolymer is melt blended with LDPE, almost 40% of the initial amount of EBAGMA is linked to the LDPE backbone. In contrast, in the case of EBAGMA/PET, FT-IR spectra indicate the total reactivity between the two components through the reaction of the epoxy group of EBAGMA with the PET terminal groups. SEM analysis shows that both master batches present two well-interconnected phases. [source]

Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA-LDPE and EBAGMA-PET Masterbatches for LDPE/PET Blends

A comparative study of oxygen transmission rates through polymer films based on fluorescence quenching

PACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2010
I. Siró
Abstract Information on oxygen permeability through polymer films is essential for some applications, especially in food packaging where the control of oxygen levels can be critical in avoiding food spoilage. A permeability testing device using fluorescence-based optical oxygen sensing was developed as a potential new instrument for measuring the oxygen permeability of packaging films. The fluorescence-based permeability tester was validated against two existing commercial oxygen permeability measuring devices, the Mocon Ox-Tran 2/20 and PBI-Dansensor OPT-5000. Oxygen transmission rates (OTR) of polylactide (PLA) and nanoclay-reinforced PLA films, as well as polyethylene/poly(ethylene terephthalate) (PE/PET) and polypropylene/poly(ethylene terephthalate) (PP/PET) laminated films were determined at 23°C and 50% relative humidity using each of these instruments. No significant differences were observed between mean OTR values obtained by the fluorescence method and the corresponding values obtained using the OPT-5000 but significantly lower values were measured when using the Mocon Ox-Tran 2/20. In general, oxygen permeability data for the tested films were within the range of values found in the literature; however, in terms of further development, the fluorescence-based technique gave OTR with relatively high standard deviation compared to the commercial methods and equipment modifications to address this issue are considered desirable. Copyright © 2010 John Wiley & Sons, Ltd. [source]

68Ga-PET: a powerful generator-based alternative to cyclotron-based PET radiopharmaceuticals

CONTRAST MEDIA & MOLECULAR IMAGING, Issue 2 2008
Melpomeni Fani
Abstract PET (positron emission tomography) is a powerful diagnostic and imaging technique which requires short-lived positron emitting isotopes. The most commonly used are accelerator-produced 11C and 18F. An alternative is the use of metallic positron emitters. Among them 68Ga deserves special attention because of its availability from long-lived 68Ge/68Ga generator systems which render 68Ga radiopharmacy independent of an onsite cyclotron. The coordination chemistry of Ga3+ is dominated by its hard acid character. A variety of mono- and bifunctional chelators have been developed which allow the formation of stable 68Ga3+complexes and convenient coupling to biomolecules. 68Ga coupling to small biomolecules is potentially an alternative to 18F- and 11C-based radiopharmacy. In particular, peptides targeting G-protein coupled receptors overexpressed on human tumour cells have shown preclinically and clinically high and specific tumour uptake. Kit-formulated precursors along with the generator may be provided, similar to the 99Mo/99mTc-based radiopharmacy, still the mainstay of nuclear medicine. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Imaging of the lymphatic system: new horizons,

CONTRAST MEDIA & MOLECULAR IMAGING, Issue 6 2006
Tristan Barrett
Abstract The lymphatic system is a complex network of lymph vessels, lymphatic organs and lymph nodes. Traditionally, imaging of the lymphatic system has been based on conventional imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI), whereby enlargement of lymph nodes is considered the primary diagnostic criterion for disease. This is particularly true in oncology, where nodal enlargement can be indicative of nodal metastases or lymphoma. CT and MRI on their own are, however, anatomical imaging methods. Newer imaging methods such as positron emission tomography (PET), dynamic contrast-enhanced MRI (DCE-MRI) and color Doppler ultrasound (CDUS) provide a functional assessment of node status. None of these techniques is capable of detecting flow within the lymphatics and, thus, several intra-lymphatic imaging methods have been developed. Direct lymphangiography is an all-but-extinct method of visualizing the lymphatic drainage from an extremity using oil-based iodine contrast agents. More recently, interstitially injected intra-lymphatic imaging, such as lymphoscintigraphy, has been used for lymphedema assessment and sentinel node detection. Nevertheless, radionuclide-based imaging has the disadvantage of poor resolution. This has lead to the development of novel systemic and interstitial imaging techniques which are minimally invasive and have the potential to provide both structural and functional information; this is a particular advantage for cancer imaging, where anatomical depiction alone often provides insufficient information. At present the respective role each modality plays remains to be determined. Indeed, multi-modal imaging may be more appropriate for certain lymphatic disorders. The field of lymphatic imaging is ever evolving, and technological advances, combined with the development of new contrast agents, continue to improve diagnostic accuracy. Published in 2006 by John Wiley & Sons, Ltd. [source]

An HPLC/mass spectrometry platform for the development of multimodality contrast agents and targeted therapeutics: prostate-specific membrane antigen small molecule derivatives

CONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2006
Valerie Humblet
Abstract The production of disease-targeted agents requires the covalent conjugation of a targeting molecule with a contrast agent or therapeutic, followed by purification of the product to homogeneity. Typical targeting molecules, such as small molecules and peptides, often have high charge-to-mass ratios and/or hydrophobicity. Contrast agents and therapeutics themselves are also diverse, and include lanthanide chelates for MRI, 99mTc chelates for SPECT, 90Y chelates for radiotherapy, 18F derivatives for PET, and heptamethine indocyanines for near-infrared fluorescent optical imaging. We have constructed a general-purpose HPLC/mass spectrometry platform capable of purifying virtually any targeted agent for any modality. The analytical sub-system is composed of a single dual-head pump that directs mobile phase to either a hot cell for the purification of radioactive agents or to an ES-TOF MS for the purification of nonradioactive agents. Nonradioactive agents are also monitored during purification by ELSD, absorbance and fluorescence. The preparative sub-system is composed of columns and procedures that permit rapid scaling from the analytical system. To demonstrate the platform's utility, we describe the preparation of five small molecule derivatives specific for prostate-specific membrane antigen (PSMA): a gadolinium derivative for MRI, indium, rhenium and technetium derivatives for SPECT, and an yttrium derivative for radiotherapy. All five compounds are derived from a highly anionic targeting ligand engineered to have a single nucleophile for N -hydroxysuccinimide-based conjugation. We also describe optimized column/mobile phase combinations and mass spectrometry settings for each class of agent, and discuss strategies for purifying molecules with extreme charge and/or hydrophobicity. Taken together, our study should expedite the development of disease-targeted, multimodality diagnostic and therapeutic agents. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Dopamine release in ventral striatum of pathological gamblers losing money

ACTA PSYCHIATRICA SCANDINAVICA, Issue 4 2010
J. Linnet
Linnet J, Peterson E, Doudet DJ, Gjedde A, Møller A. Dopamine release in ventral striatum of pathological gamblers losing money. Objective:, To investigate dopaminergic neurotransmission in relation to monetary reward and punishment in pathological gambling. Pathological gamblers (PG) often continue gambling despite losses, known as ,chasing one's losses'. We therefore hypothesized that losing money would be associated with increased dopamine release in the ventral striatum of PG compared with healthy controls (HC). Method:, We used Positron Emission Tomography (PET) with [11C]raclopride to measure dopamine release in the ventral striatum of 16 PG and 15 HC playing the Iowa Gambling Task (IGT). Results:, PG who lost money had significantly increased dopamine release in the left ventral striatum compared with HC. PG and HC who won money did not differ in dopamine release. Conclusion:, Our findings suggest a dopaminergic basis of monetary losses in pathological gambling, which might explain loss-chasing behavior. The findings may have implications for the understanding of dopamine dysfunctions and impaired decision-making in pathological gambling and substance-related addictions. [source]

Regional cerebral brain metabolism correlates of neuroticism and extraversion

DEPRESSION AND ANXIETY, Issue 3 2006
Thilo Deckersbach Ph.D.
Abstract Factor-analytic approaches to human personality have consistently identified several core personality traits, such as Extraversion/Introversion, Neuroticism, Agreeableness, Consciousness, and Openness. There is an increasing recognition that certain personality traits may render individuals vulnerable to psychiatric disorders, including anxiety disorders and depression. Our purpose in this study was to explore correlates between the personality dimensions neuroticism and extraversion as assessed by the NEO Five-Factor Inventory (NEO-FFI) and resting regional cerebral glucose metabolism (rCMRglu) in healthy control subjects. Based on the anxiety and depression literatures, we predicted correlations with a network of brain structures, including ventral and medial prefrontal cortex (encompassing anterior cingulate cortex and orbitofrontal cortex), insular cortex, anterior temporal pole, ventral striatum, and the amygdala. Twenty healthy women completed an 18FFDG (18F-fluorodeoxyglucose) positron emission tomography (PET) scan at rest and the NEO-FFI inventory. We investigated correlations between scores on NEO-FFI Neuroticism and Extraversion and rCMRglu using statistical parametric mapping (SPM99). Within a priori search territories, we found significant negative correlations between Neuroticism and rCMRglu in the insular cortex and positive correlations between Extraversion and rCMRglu in the orbitofrontal cortex. No significant correlations were found involving anterior cingulate, amygdala, or ventral striatum. Neuroticism and Extraversion are associated with activity in insular cortex and orbitofrontal cortex, respectively. Depression and Anxiety 23:133,138, 2006. © 2006 Wiley-Liss, Inc. [source]

VMAT2 quantitation by PET as a biomarker for ,-cell mass in health and disease

DIABETES OBESITY & METABOLISM, Issue 2008
M. Freeby
The common pathology underlying both type 1 and type 2 diabetes (T1DM and T2DM) is insufficient ,-cell mass (BCM) to meet metabolic demands. An important impediment to the more rapid evaluation of interventions for both T1DM and T2DM lack of biomarkers of pancreatic BCM. A reliable means of monitoring the mass and/or function of ,-cells would enable evaluation of the progression of diabetes as well as the monitoring of pharmacologic and other interventions. Recently, we identified a biomarker of BCM that is quantifiable by positron emission tomography (PET). PET is an imaging technique which allows for non-invasive measurements of radioligand uptake and clearance, is sensitive in the pico- to nanomolar range and of which the results can be deconvoluted into measurements of receptor concentration. For BCM estimates, we have identified VMAT2 (vesicular monoamine transporter type 2) as a biomarker and [11C] DTBZ (dihydrotetrabenazine) as the transporter's ligand. VMAT2 is highly expressed in ,-cells of the human pancreas relative to other cells of the endocrine and exocrine pancreas. Thus measurements of [11C] DTBZ in the pancreas provide an indirect measurement of BCM. Here we summarize our ongoing efforts to validate the clinical utility of this non-invasive approach to real-time BCM measurements [source]

Cytologic diagnosis of pancreatic endocrine tumors by endoscopic ultrasound-guided fine-needle aspiration: A review

DIAGNOSTIC CYTOPATHOLOGY, Issue 9 2006
Fuju Chang M.D., Ph.D.
Abstract Precise localization and diagnosis of pancreatic endocrine tumors (PETs) is important, because pancreatic PETs have different clinical and biological behavior and treatment modalities than do exocrine pancreatic tumors. In contrast to the much more common exocrine adenocarcinomas, cytologic studies of PET are relatively rare and many cytopathologists lack experience with the cytomorphologic features of these tumors. During the last 10 yr, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has matured into an accurate, highly sensitive, and cost-effective modality for the preoperative localization of pancreatic PETs. This has resulted in an increased number of PETs first sampled as cytology specimens. This manuscript focuses on the cytomorphologic features most suggestive of pancreatic PETs, differential diagnosis, and diagnostic pitfalls of PETs. The technical development of EUS-guided FNA and the ancillary studies for pancreatic PETs are also reviewed. The data summarized in this review indicate that EUS-FNA is a valuable method in the recognition of pancreatic PETs and in most cases cytopathologists could reach a correct diagnosis of these tumors, including their hormone producing capability on aspirated cytologic material. Diagn. Cytopathol. 2006;34:649,658. © 2006 Wiley-Liss, Inc. [source]

Cognitive impairment in schizophrenia:its impact on social functioning

ACTA PSYCHIATRICA SCANDINAVICA, Issue 400 2000
P. F. Liddle
Objective: To examine cognitive impairment in schizophrenia and its impact on social functioning. Method: Cohort studies recording cognitive and social development, studies of predictors of poor community outcome, and evidence from brain imaging studies are reviewed. Results: Executive function deficits, and poor performance in verbal memory, vigilance, and working memory tests are strong predictors of poor community outcome and impairment in skills learning. PET scans of regional cerebral blood flow suggest a dynamic imbalance between different cerebral areas rather than overall loss of brain function. Conclusion: Chronic cognitive impairment is the strongest predictor of social disability. Results suggest that the impairment of brain function associated with executive deficits is not necessarily irreversible and may therefore be treatable with appropriate drug therapy. [source]

Recent development and potential use of µ- and ,-opioid receptor ligands in positron emission tomography studies

DRUG DEVELOPMENT RESEARCH, Issue 12 2006
Gjermund Henriksen
Abstract Quantitative non-invasive imaging of target structures in the human central nervous system provided by positron emission tomography (PET) permits investigation of the relationship between molecular events and pharmacological effects in living humans. Due to their prominent role in opiate and stimulant drug misuse and dependence, as well as in nociceptive signaling, µ- and ,-opioid receptors are potential targets for advances in neuro(psycho)pharmacological treatment of these illnesses and syndromes. In this review, we describe recent developments in specific positron emitting radiopharmaceuticals for these opioid receptor subclasses. Implications for further advances and clinical applications of the labeled ligands are discussed. Drug Dev. Res. 67:890,904, 2006. © 2007 Wiley-Liss, Inc. [source]

Positron emission tomography and its use to image the occupancy of drug binding sites

DRUG DEVELOPMENT RESEARCH, Issue 2 2003
S. John Gatley
Abstract The development of positron emission tomography (PET) and the ability to synthesize compounds labeled with the short-lived positron emitters 11C and 18F has made possible the imaging and quantification of drug binding sites in the human body. By conducting PET studies with an appropriate radioligand before and after treatment with a drug, the fraction of the total number of binding sites that is occupied by the drug (the "occupancy" of the site) can often be determined. To the extent that occupancy is a good indicator of pharmacological activity, such PET experiments can aid the development of drug dosage regimens. Some of the general issues involved in PET studies of drug occupancy are discussed. There have been many such studies involving antipsychotic drugs and dopamine D2 receptor radioligands. Since neuroleptics have been extensively reviewed elsewhere, only the major findings are discussed here. Other binding sites (and drug classes) in the dopamine system to which this methodology has been applied include: the dopamine transporter (stimulant drugs) and monoamine oxidase A and B (antidepressant drugs). Occupancy studies are also possible for many drug targets beyond the dopamine system. Drug Dev. Res. 59:194,207, 2003. © 2003 Wiley-Liss, Inc. [source]

Imaging studies of biodistribution and kinetics in drug development

DRUG DEVELOPMENT RESEARCH, Issue 2 2003
Marc S. Berridge
Abstract Although the intravenous route of administration is rarely used for drugs, it is by far the most common route for PET and SPECT radiotracers. This article discusses the use of planar and tomographic nuclear medicine technologies to image and quantify the distribution of drugs after local administration. In principle, this would include topical dermatologic, otic, ophthalmic, rectal, and vaginal administration, as well as the intramuscular, oral, and inhalation routes, although precedents do not yet exist for all of these. The studies reviewed focus mainly on oral ingestion and oral and nasal inhalation. The use of nondrug tracers for formulations is discussed, principally with planar imaging or SPECT using radionuclides such as 99mTc, as well as PET imaging where the active ingredient of a formulation can be labeled with 11C or sometimes 18F. An example of the latter type is a study of the deposition and kinetics in the lungs and airways of triamcinolone acetonide, an antiinflammatory steroid used for topical treatment of allergic rhinitis and asthma, dispensed from an inhaler. PET has high potential for evaluation of different formulations and delivery devices in the development of topically applied drugs. Drug Dev. Res. 59:208,226, 2003. © 2003 Wiley-Liss, Inc. [source]

Assessment of Residual Viability by Enoximone Echocardiography in Patients with Previous Myocardial Infarction Correlation with Positron Emission Tomographic Studies and Functional Follow-Up

ECHOCARDIOGRAPHY, Issue 5 2010
Fei Lu M.D.
Background: The aim of this study was to evaluate enoximone echocardiography (EE) for the identification of residual myocardial viability in postinfarction patients. Findings obtained during EE were compared with those acquired by myocardial uptake of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and functional follow-up results. Methods: Twenty-five patients underwent EE and PET 18F-FDG studies. An asynergic segment was considered as having contractile enhancement when the wall motion score decreased by ,1 grade during EE and was defined as viable if 18F-FDG uptake score was ,2 grade on PET. Results: Of 293 dysfunctional segments at baseline, 139 (47%) were viable by PET criteria; 117 (40%) had contractile enhancement induced by enoximone (P = 0.07). Agreement between EE and PET was found in 75% of involved segments (K = 0.46, P < 0.001). The majority of discrepancies (65%, P < 0.01) were mainly due to discordant segments in which PET revealed evidence of 18F-FDG uptake but EE showed no change in wall motion. In 179 revascularized segments, negative predictive value for functional recovery of both tests reached the same value (89% for both), whereas positive predictive value was 82% for EE and 68% for PET, respectively (P < 0.05). Sensitivity was 85% for EE and 88% for PET (P = ns); specificity was 87% and 70%, respectively (P < 0.01). Conclusions: EE yields a fair concordance with PET study. Compared with PET, despite a similar negative accuracy, EE shows a greater specificity for prediction of function recovery after revascularization. (Echocardiography 2010;27:544-551) [source]

Viable Myocardium: How Much Is Enough?

ECHOCARDIOGRAPHY, Issue 1 2005
A Comparison of Viability by Comparative Imaging Techniques to Assess the Quantity, Functionality of Ischemic Myocardium
Left ventricular systolic dysfunction is mainly a result of coronary artery disease (CAD). Decrease in myocardial contractility results as a response to a chronic hypoperfusion state that produces a change in cardiac myocyte metabolism, resulting in a perfusion-contraction mismatch in which function is sacrificed for survival. If revascularization is performed in a timely fashion, metabolism can be restored leading to recovery of function. Through the use of noninvasive imaging modalities, assessing myocardial viability can be easily performed and will aid in selecting those patients who will benefit from revascularization. Viable myocardium can be identified by nuclear modalities that have a high sensitivity but a lower specificity, such as thallium-201 single photon emission computed tomography and positron emission tomography (PET); or by the use of dobutamine stress echocardiogram (DSE), which has a decreased sensitivity but a better specificity. A modality that is increasingly being used with an overall good sensitivity and specificity is contrast-enhanced magnetic resonance imaging. The purpose of this review is to explore the amount of myocardial viability that is relevant to pursue revascularization, since as myocardial function improves there is a decrease in morbidity and mortality from heart failure and arrhythmias. [source]

Aphasic or amnesic status epilepticus detected on PET but not EEG

EPILEPSIA, Issue 2 2009
Christine Dong
Summary Purpose:, To describe five patients with ictal aphasia and one patient with ictal amnesia, who had focal positron emission tomography (PET) hypermetabolism but no clear ictal activity on electroencephalography (EEG). Methods:,18F-Fluorodeoxyglucose (FDG),PET scans with concomitant EEG were obtained in five patients with suspected ictal aphasia or ictal amnesia without ictal activity on EEG. We reviewed medical history, EEG, imaging data, and treatment outcome. Results:, Brain magnetic resonance imaging (MRI) showed no structural abnormalities in any of the patients. EEG showed left temporal irregular delta activity in three patients, with aphasia and nonspecific abnormalities in two other patients, all without clear ictal pattern. All patients demonstrated focal hypermetabolism on PET scan. The hypermetabolism was in the left frontotemporal region in patients with ictal aphasia and in the bilateral hippocampal region in the patient with amnesia. Three patients who received intravenous benzodiazepines during their episodes had transient clinical improvement. With antiepileptic drug (AED) treatment, symptoms gradually resolved in all patients. Concomitant resolution of PET hypermetabolism was documented in three patients who had follow up scans. One patient with ictal aphasia later developed recurrent episodes, each with recurrent PET hypermetabolism. This patient and one other patient required immune-modulating therapy in addition to AEDs. Discussion:, FDG-PET imaging should be considered as a diagnostic tool in patients with suspected ictal aphasia or amnesia, who fail to show clear evidence of ictal activity on EEG. [source]

Evaluation of epileptogenic networks in children with tuberous sclerosis complex using EEG-fMRI

EPILEPSIA, Issue 5 2008
Julia Jacobs
Summary Purpose: Ninety percent of patients with tuberous sclerosis complex (TSC) have epilepsy. Identification of epileptogenic areas can be difficult and studies are needed to characterize the epileptogenic network in more detail. Methods: Five children with TSC and focal epilepsy were studied using simultaneous EEG and functional MRI recordings. Tubers were marked by a neuroradiologist on the anatomical MRI. Spike-associated BOLD (blood oxygenation level-dependent) responses were superimposed with lesions. Results: Thirteen different types of interictal epileptiform discharges (IED) were analyzed with 12 showing a BOLD response, all involving more than one tuber. Five studies had tubers with activations exclusively within the lesion, three studies had lesional activations extending to perilesional areas, and two studies had activations involving exclusively perilesional areas of at least one tuber. Deactivations exclusively within a tuber were found in six studies, lesional deactivations extending to perilesional areas were found in four studies, and tubers with exclusively perilesional deactivations were found in five studies. A BOLD response was found in at least one tuber in the lobe of IED generation and presumed seizure onset (according to telemetry) in all patients. In four patients, the same tubers were involved following different IED localizations. The observed changes were always multifocal, sometimes involving tubers distant from the IED field. Discussion: These findings suggest extended epileptogenic networks in patients with TSC, which exceed networks described in PET and SPECT studies. It was possible to identify specific interictally active tubers. EEG-fMRI provides a noninvasive method to select tubers and areas at their borders for further presurgical investigations. [source]

,-[11C]methyl-L-tryptophan uptake in patients with periventricular nodular heterotopia and epilepsy

EPILEPSIA, Issue 5 2008
Jun Natsume
Summary Background:,-[11C]methyl-L-tryptophan (,-MTrp) positron emission tomography (PET) is a promising tool in the localization of the epileptogenic area in selected group of focal epilepsy patients. Electrophysiological evidence suggests the involvement of the neocortex in periventricular nodular heterotopia (PVNH). Purpose: To determine whether ,-MTrp PET can detect neocortical changes in patients with PVNH. Methods: Four patients (2 male, mean age 28, range 23,35 years) with PVNH and intractable seizures were studied. The functional image in each patient was compared with those from 21 healthy controls (mean age 34.6 ± 14.2 years) by using statistical parametric mapping (SPM). The location of increased ,-MTrp uptake was compared with the location of the EEG focus. A significant cluster was defined as a cluster with a height p = 0.005 and an extent threshold 100. Results:,-MTrp PET revealed increased cortical uptake in two of four patients. The area of increased ,-MTrp uptake in one patient was widespread. In the other patient, the area of increased uptake did not include the region where most seizures were generated on EEG. ,-MTrp PET did not show increased uptake in the heterotopic nodules in any of the patients. Conclusions:,-MTrp PET suggests abnormal metabolism of tryptophan in the neocortex. The increased uptake may be diffuse and may not co-localize with the EEG focus. This preliminary study suggests that ,-MTrp PET may be useful, in conjunction with other evaluations, in localizing epileptic focus in patients with PVNH and refractory seizures. [source]

Molecular and diffusion tensor imaging of epileptic networks

EPILEPSIA, Issue 2008
Aimee F. Luat
Summary Several studies have shown that seizure-induced cellular and molecular changes associated with chronic epilepsy can lead to functional and structural alterations in the brain. Chronic epilepsy, when medically refractory, may be associated with an expansion of the epileptic circuitry to involve complex interactions between cortical and subcortical neuroanatomical substrates. Progress in neuroimaging has led not only to successful identification of epileptic foci for surgical resection, but also to an improved understanding of the functional and microstructural changes in long-standing epilepsy. Positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are all promising tools that can assist in elucidating the underlying pathophysiology in chronic epilepsy. Studies using PET scanning have demonstrated dynamic changes associated with the evolution from acute to chronic intractable epilepsy. Among these changes are data to support the existence of secondary epileptogenesis in humans. MRI with DTI is a powerful tool which has the ability to characterize microstructural abnormalities in epileptic foci, and to demonstrate the white matter fibers and tracts participating in the epileptic network. In this review, we illustrate how PET and DTI can be applied to depict the functional and microstructural alterations associated with chronic epilepsy. [source]

Coexistence of Idiopathic Rolandic Epilepsy and CSWS in Two Families

EPILEPSIA, Issue 10 2006
Xavier De Tiège
Summary:,Purpose: To report two families combining benign childhood epilepsy with centrotemporal spikes (BCECS) and cryptogenic epilepsy with continuous spike,waves during sleep (CSWS) in first-degree relatives. Methods: Clinical, EEG, and cerebral imaging data are described. Results: Family 1: The proband was 3 years old at epilepsy onset. First seizures were convulsive, with centrotemporal spikes on EEG. At age 5 years, he had complex partial seizures, psychomotor regression, and centrotemporal CSWS. [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) showed left parietal hypermetabolism. After several antiepileptic drug (AED) trials, valproate (VPA) and ethosuximide (ESM) induced seizure remission, CSWS disappearance, and psychomotor improvement. Learning disabilities, however, persisted. Family history was remarkable for BCECS in his father. Family 2: The proband was 2 years old at epilepsy onset. First seizures were convulsive, with centrotemporal CSWS on EEG. Despite several AED trials including corticosteroids, focal negative myoclonia, atypical absences, and psychomotor regression occurred, leading to severe mental retardation. FDG-PET showed bilateral parietal hypermetabolism. Vagus nerve stimulator was implanted. Her family history was remarkable for BCECS in her father and febrile convulsions in infancy in her mother. Conclusions: These data suggest the existence of a common genetic basis between BCECS and cryptogenic epilepsies with CSWS. The higher expression in patients with CSWS could be related to other genetic or acquired factors. These data suggest that these epileptic syndromes constitute edges of a continuum. [source]

Decreased Dopamine D2/D3-Receptor Binding in Temporal Lobe Epilepsy: An [18F]Fallypride PET Study

EPILEPSIA, Issue 8 2006
Konrad J. Werhahn
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 age-matched controls with positron emission tomography (PET) by using the high-affinity dopamine D2/D3-receptor ligand [18F]Fallypride ([18F]FP) suitable for imaging extrastriatal binding. TLE was defined by interictal and ictal video-EEG, magnetic resonance imaging (MRI), and [18F]fluorodeoxyglucose ([18F]FDG)-PET and was due to hippocampal sclerosis (HS), based on histology in all patients. Primary analysis was based on regions of interest (ROIs) defined on individual MRIs. For each patient, binding potential (BP) was calculated by using the simplified reference tissue model, and the epileptogenic was compared with the unaffected hemisphere in each ROI. To confirm the results, an additional voxel-based group analysis was performed by using statistical parametric mapping. Results: Compared with controls, [18F]FP BP was significantly decreased in the epileptogenic temporal lobe in all patients. On ROI analysis, this reduction was evident in areas surrounding the seizure-onset zone at the pole (,34.2%) and lateral aspects (,32.9%) of the temporal lobe. Although the hippocampus [18F]FDG uptake (,8.1%) and hippocampal MR volume (,35.1%) were significantly reduced, no significant decrease of [18F]FP BP was found. Reduction of [18F]FP BP did not correlate with hippocampal atrophy. Conclusions: D2/D3-receptor binding is reduced at the pole and in lateral aspects of the epileptogenic temporal lobe in patients with mesial TLE and HS. This area might correspond to "the irritative zone," indicating that D2/D3 receptors might play a specific role in the pathophysiology of mesial TLE. [source]

Brain Blood-flow Alterations Induced by Therapeutic Vagus Nerve Stimulation in Partial Epilepsy: II.

EPILEPSIA, Issue 9 2004
Low Levels of Stimulation, Prolonged Effects at High
Summary:,Purpose: To measure vagus nerve stimulation (VNS)-induced cerebral blood flow (CBF) effects after prolonged VNS and to compare these effects with immediate VNS effects on CBF. Methods: Ten consenting partial epilepsy patients had positron emission tomography (PET) with intravenous [15O]H2O. Each had three control scans without VNS and three scans during 30 s of VNS, within 20 h after VNS began (immediate-effect study), and repeated after 3 months of VNS (prolonged study). After intrasubject subtraction of control from stimulation scans, images were anatomically transformed for intersubject averaging and superimposed on magnetic resonance imaging (MRI) for anatomic localization. Changes on t-statistical maps were considered significant at p < 0.05 (corrected for multiple comparisons). Results: During prolonged studies, CBF changes were not observed in any regions that did not have CBF changes during immediate-effect studies. During both types of studies, VNS-induced CBF increases were similarly located in the bilateral thalami, hypothalami, inferior cerebellar hemispheres, and right postcentral gyrus. During immediate-effect studies, VNS decreased bilateral hippocampal, amygdalar, and cingulate CBF and increased bilateral insular CBF; no significant CBF changes were observed in these regions during prolonged studies. Mean seizure frequency decreased by 25% over a 3-month period between immediate and prolonged PET studies, compared with 3 months before VNS began. Conclusions: Seizure control improved during a period over which some immediate VNS-induced CBF changes declined (mainly over cortical regions), whereas other VNS-induced CBF changes persisted (mainly over subcortical regions). Altered synaptic activities at sites of persisting VNS-induced CBF changes may reflect antiseizure actions. [source]

Parietal Lobe Epilepsy: The Semiology, Yield of Diagnostic Workup, and Surgical Outcome

EPILEPSIA, Issue 6 2004
Dong Wook Kim
Summary: Purpose: To characterize the clinical features, the prognostic value, and diagnostic sensitivities of various presurgical evaluations and the surgical outcomes in parietal lobe epilepsy (PLE), we describe 40 patients who were diagnosed as having PLE, including 27 surgically treated patients. Methods: The diagnosis was established by means of a standard presurgical evaluation, including magnetic resonance imaging (MRI), fluorodeoxyglucose,positron emission tomography (FDG-PET), ictal single-photon emission tomography (SPECT), and scalp video-electroencephalography (EEG) monitoring, with additional intracranial EEG monitoring in selected cases. Results: Among the 40 patients, 27 experienced at least one type of aura. The most common auras were somatosensory (13 patients), followed by affective, vertiginous, and visual auras. The patients had diverse manifestations. Eighteen patients showed simple motor seizure, followed by automotor seizure, and dialeptic seizure. Two patients manifested generalized tonic,clonic seizures only, and 19 patients experienced more than one type of seizure. The surgical outcome was favorable in 22 of 26 patients including 14 who were seizure free. Patients with localized MRI abnormality had a higher probability to be seizure free, with marginal significance (p = 0.062), whereas other diagnostic modalities failed to predict the surgical outcome. In the seizure-free group, localization sensitivity was 64.3% by MRI, 50% by PET, 45.5% by ictal SPECT, and 35.7% by ictal EEG. The concordance rate of the various diagnostic modalities was higher in the seizure-free group than in the non,seizure-free group, although it did not reach statistical significance. Conclusions: Seizures, in the case of PLE, can manifest themselves in a wider variety of ways than was previously thought. Surgical outcome was favorable in most of the patients. MRI abnormality and concordance of different diagnostic modalities were associated with high seizure-free rate. [source]

Neocortical Temporal FDG-PET Hypometabolism Correlates with Temporal Lobe Atrophy in Hippocampal Sclerosis Associated with Microscopic Cortical Dysplasia

EPILEPSIA, Issue 4 2003
Beate Diehl
Summary: ,Purpose: Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), with or without cortical dysplasia (CD), is associated with atrophy of the hippocampal formation and regional fluorodeoxyglucose positron-emission tomography (FDG-PET) hypometabolism. The relation between areas of functional and structural abnormalities is not well understood. We investigate the relation between FDG-PET metabolism and temporal lobe (TL) and hippocampal atrophy in patients with histologically proven isolated HS and HS associated with CD. Methods: Twenty-three patients underwent en bloc resection of the mesial and anterolateral neocortical structures. Ten patients were diagnosed with isolated HS; 13 patients had associated microscopic CD. Temporal lobe volumes (TLVs) and hippocampal volumes were measured. Magnetic resonance imaging (MRI) and PET were co-registered, and regions of interest (ROIs) determined as gray matter of the mesial, lateral, and anterior temporal lobe. Results: All patients (HS with or without CD) had significant ipsilateral PET hypometabolism in all three regions studied (p < 0.0001). In patients with isolated HS, the most prominent hypometabolism was in the anterior and mesial temporal lobe, whereas in dual pathology, it was in the lateral temporal lobe. TLVs and hippocampal volumes were significantly smaller on the epileptogenic side (p < 0.05). The PET asymmetries ipsilateral/contralateral to the epileptogenic zone and TLV asymmetries correlated significantly for the anterior and lateral temporal lobes (p < 0.05) in the HS+CD group, but not in the isolated HS group. Mesial temporal hypometabolism was not significantly different between the two groups. Conclusions: Temporal neocortical microscopic CD with concurrent HS is associated with more prominent lateral temporal metabolic dysfunction compared with isolated HS in TL atrophy. Further studies are needed to confirm these findings and correlate the PET hypometabolic patterns with outcome data in patients operated on for HS with or without CD. [source]

Correlation of Hippocampal Glucose Oxidation Capacity and Interictal FDG-PET in Temporal Lobe Epilepsy

EPILEPSIA, Issue 2 2003
Stefan Vielhaber
Summary: ,Purpose: Interictal [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) demonstrates temporal hypometabolism in the epileptogenic zone of 60,90% of patients with temporal lobe epilepsy. The pathophysiology of this finding is still unknown. Several studies failed to show a correlation between hippocampal FDG-PET hypometabolism and neuronal cell loss. Because FDG is metabolized by hexokinase bound to the outer mitochondrial membrane, we correlated the glucose-oxidation capacity of hippocampal subfields obtained after surgical resection with the corresponding hippocampal presurgical FDG-PET activity. Methods: In 16 patients with electrophysiologically confirmed temporal lobe epilepsy, we used high-resolution respirometry to determine the basal and maximal glucose-oxidation rates in 400-,m-thick hippocampal subfields obtained after dissection of human hippocampal slices into the CA1 and CA3 pyramidal subfields and the dentate gyrus. Results: We observed a correlation of the FDG-PET activity with the maximal glucose-oxidation rate of the CA3 pyramidal subfields (rp = 0.7, p = 0.003) but not for the regions CA1 and dentate gyrus. In accordance with previous studies, no correlation of the FDG-PET to the neuronal cell density of CA1, CA3, and dentate gyrus was found. Conclusions: The interictal hippocampal FDG-PET hypometabolism in patients with temporal lobe epilepsy is correlated to the glucose-oxidation capacity of the CA3 hippocampal subfield as result of impaired oxidative metabolism. [source]

Operative Results without Invasive Monitoring in Patients with Frontal Lobe Epileptogenic Lesions

EPILEPSIA, Issue 10 2001
A. Mariottini
Summary: ,Purpose: To further explore the still controversial issues regarding whether all or most candidates for epilepsy surgery should be investigated preoperatively with invasive long-term video-EEG monitoring techniques (ILTVE). Methods: We studied five patients with intractable seizures since early childhood using the same protocol: clinical evaluation, magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (FLAIR) sequences, long-term video-EEG (LTVE) monitoring with scalp electroencephalogram (EEG), interictal single photon emission computed tomography (SPECT), positron emission tomography (PET), and neuropsychological testing. The patients' seizures had clinical features suggesting a frontal lobe (FL) origin. MRI scans revealed focal cortical dysplasia (CD) in four patients and a probable gliotic lesion in the fifth. The findings in both PET and SPECT images were congruent with those of the MRI. Scalp LTVE failed to localize the ictal onset, although the data exhibited features suggestive of both CDs and FL seizures. On the basis of these results, surgery was performed with intraoperative corticography, and the cortical area exhibiting the greatest degree of spiking was ablated. Results: Histopathologic study of four of the resected specimens confirmed the presence of CD, whereas in the fifth, there were features consistent with a remote encephaloclastic lesion. There were no postoperative deficits. Seizures in three of the patients were completely controlled at 2,3.5 years of follow-up; a fourth patient is still having a few seizures, which have required reinstitution of pharmacotherapy, and the fifth has obtained 70% control. All patients have had significant improvement in psychosocial measures. For comparison, five patients with generally similar clinical and neuroradiologic features to the previous group underwent preoperative ILTVE monitoring. The surgical outcomes between the two groups have not differed significantly. Conclusions: We conclude that patients with FL epilepsies may be able to undergo successful surgery without preoperative ILTVE monitoring, provided there is high concordance between neuroimaging tests (MRI, SPECT, PET) and the seizure phenotypes, even when routine EEGs and scalp LVTE fail to localize ictal onset unambiguously. The surgical outcomes of these patients generally paralleled those of the other subjects who also had FL epilepsy but who were operated on only after standard ILTVE monitoring. [source]

High levels of serum prostate-specific antigen due to PSA producing follicular non-Hodgkin's lymphoma

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 2 2007
Jan Jelrik Oosterheert
Abstract Objective:, Both carcinoma of the prostate and non-Hodgkin's lymphoma are common in elderly patients. Measurement of serum prostate-specific antigen (PSA) is a frequently used tool to diagnose and monitor prostate carcinoma and is generally specific for diseases of the prostate. Case:, We describe a 68-yr-old patient with voiding difficulties and high PSA levels, but without inflammatory or malignant changes upon multiple transrectal ultrasound guided prostate biopsies. Digital rectal examination was normal. Laboratory showed a strongly elevated PSA level (62 ,g/L, Immulight 2000®; DPC, USA). A CT-scan showed a retroperitoneal process with mass in the right pelvis and infiltration of the bladder wall, suggestive for metastatic prostate carcinoma. Surgical excision of an axillary lymph node set the diagnosis at a stage IV follicular lymphoma, Berard grade I to II in which the majority of neoplastic cells expressed PSA. After lymphoma-specific treatment, there was a positron emission tomography (PET) confirmed complete remission with normal PSA levels (6 ,g/L), which still persists. Conclusion:, Although rare, high PSA levels can be due to the presence of non-Hodgkin's lymphoma. Such a diagnosis should be considered when patients present with lymphadenopathy other than regional prostatic lymphadenopathy. [source]