L Balkay

Publications of L Balkay

• Performance test of the MiniPET-II small animal scanner according to the NEMA NU-4 standard

  Authors: S.A. Kis, I. Lajtos, M. Emri, L. Tron, G. Opposits, T. Bukki, G. Hegyesi, J. Imrek, I. Valastyan, J. Molnar, D. Novak, L. Balkay

  Nuclear Science Symposium Conference Record (NSS/MIC), 2009 IEEE; 12/2009

  A full ring small animal PET camera (MiniPET-II) has been built in our institute as part of an R+D project. In this work we determined the performance parameters of the MiniPET-II scanner. TheA full ring small animal PET camera (MiniPET-II) has been built in our institute as part of an R+D project. In this work we determined the performance parameters of the MiniPET-II scanner. The measurements and data evaluation for this purpose were based on the National Electrical Manufacturers Association (NEMA) NU-4 standards. The spatial resolution varies between 1.4 to 2.1 mm from central to 25 mm radial distances. The system sensitivity was 1.14%. The counting rate capability, expressed in noise equivalent counting rate (NEC), was shown to peak of over 55.1 kcps at 38.9 MBq using a mouse phantom. The scatter fraction with the same acquisition was 12.3%. Evaluations of image quality and quantization accuracy were also performed using the NEMA NU-4 required image-quality phantom and animal studies. The study proved that the MiniPET-II scanner has a good imaging capability and ability to perform real animal studies.

• Integration of standard myocardial and epicardial segmentation: Validation by computed tomography and autopsy studies

  Authors: G. Szabo, R. Veisz, P. Gergely, L. Balkay, L. Herczeg, J. Varga, R. Kolozsvari, T. Ungvari, I. Racz, I. Edes, Z. Koszegi

  Computers in Cardiology, 2009; 10/2009

  Background: The epicardial coronary segmentations have not established the relation between the epicardial branches and the supplied myocardial segments Methods: The coronary angiograms of 37Background: The epicardial coronary segmentations have not established the relation between the epicardial branches and the supplied myocardial segments Methods: The coronary angiograms of 37 patients were analyzed by a computer program called Holistic Coronary Care. Results: The analysis of the coronary angiograms showed that out of the 17 left ventricular segments 9.5±1.9, 3.3±2.4 and 4.2±2.5 were supplied by the left anterior descending, the left circumflex and the right coronary artery, respectively. A highly significant correlation was found between the angiographic and both the CT and the autopsy determination of the number of left ventricular segments (r=0.97 and 0.94, p<0.001). Conclusions: Coronary angiography from multiple projections can determine accurately the supplied left ventricular segments of the 3 main coronary branches.

• Software development framework supporting multimodal tomographic imaging

  Authors: M. Emri, G. Opposits, S.A. Kis, L. Tron, P. Veres, A. Panyik, I. Valastyan, J. Imrek, J. Molnar, D. Novak, A. Kerek, L. Balkay

  Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006

  Engineers specialized in multimodal tomography regularly face a wide scale of programming tasks requiring an integrated software system to ensure cost efficiency. Accordingly, a software developmentEngineers specialized in multimodal tomography regularly face a wide scale of programming tasks requiring an integrated software system to ensure cost efficiency. Accordingly, a software development framework has been worked out comprising libraries for cluster-based data acquisition, image reconstruction, management of data files and complex multimodal volumetric visualization. This framework enabled us to develop complex software for our miniPET project [Kis et al., 2005], This software contains a graphical application integrating data acquisition, cluster monitoring, event sorting, image reconstruction, interactive image processing tools for advanced multimodal visualization. It also contains utilities to solve these tasks without graphical user interface. The components of our acquisition program can run on embedded Linux systems making new ways to develop any other types of data acquisition software that uses embedded Linux systems. A versatile development framework is developed containing specific libraries and special file formats that support multimodal tomography. This framework was successfully used to elaborate our complex miniPET software.

• Development of an Improved Detector Module for miniPET-II

  Authors: J. Imrek, G. Hegyesi, G. Kalinka, J. Molnar, D. Novak, I. Valastyan, J. Vegh, L. Balkay, M. Emri, S. Kis, L. Tron, T. Biikki, Z. Szabo, A. Kerek

  Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006

  We present a new detector module developed for miniPET-II, the second generation of the miniPET small animal PET scanners. The improved module features new hardware components for better performance:We present a new detector module developed for miniPET-II, the second generation of the miniPET small animal PET scanners. The improved module features new hardware components for better performance: LySO crystal material, increased number of crystal segments, Hamamatsu H9500 PSPMT, Xilinx Virtex-4 FPGA and Gigabit Ethernet. However, the principle of operation is the same: no hardware coincidence detection is implemented, data is acquired in list mode and transfered over an Ethernet network. The resulting new module is more suitable for full ring configurations.

• Development of an FPGA-Based Data Acquisition Module for Small Animal PET

  Authors: J. Imrek, D. Novak, G. Hegyesi, G. Kalinka, J. Molnar, J. Vegh, L. Balkay, M. Emri, G. Molnar, L. Tron, I. Bagamery, T. Bukki, S. Rozsa, Z. Szabo, A. Kerek

  Nuclear Science, IEEE Transactions on. 11/2006;

  We report on the design of a data acquisition (DAQ) module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is builtWe report on the design of a data acquisition (DAQ) module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is built up from strictly identical DAQ modules, and which has no built-in hardware limitation on the maximum number of modules. The developed DAQ module comprises of an LSO scintillator crystal block, a position sensitive PMT, analog signal conditioning circuits, a digitizer, an field programmable gate array (FPGA) for digital signal processing, and a communication module through which the collected data are sent to a cluster of computers for postprocessing and storage. Instead of implementing hardware coincidence detection between the modules, we attach a precise time stamp to each event in our design, and the coincidence is determined by the data collecting computers during postprocessing. The digital CFD algorithm implemented in the FPGA gives a time resolution of 2 ns FWHM for real detector signals

• Ethernet Based Distributed Data Acquisition System for a Small Animal PET

  Authors: G. Hegyesi, J. Imrek, G. Kalinka, J. Molnar, D. Novak, J. Vegh, L. Balkay, M. Emri, S.A. Kis, G. Molnar, L. Tron, I. Valastyan, I. Bagamery, T. Bukki, S. Rozsa, Z. Szabo, A. Kerek

  Nuclear Science, IEEE Transactions on. 09/2006;

  We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. EachWe report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8times8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer including a digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system and coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and generates a time stamp with a coincidence resolution of less than 2 ns. The data acquisition system is based on Ethernet network and is highly scalable in size and performance

• Performance characteristics of a miniPET scanner dedicated to small animal imaging

  Authors: S.A. Kis, I. Valastyan, Gy. Hegyesi, J. Imrek, G. Kalinka, J. Molnar, D. Novak, J. Vegh, L. Balkay, M. Emri, G. Molnar, I. Bagamery, T. Bukki, S. Rozsa, Zs. Szabo, A. Kerek, L. Tron

  Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005

  An easy to scale up modular PET scanner was developed for imaging small animals. Energy resolution, spatial resolution and count rate performance were determined as system parameters. TheAn easy to scale up modular PET scanner was developed for imaging small animals. Energy resolution, spatial resolution and count rate performance were determined as system parameters. The configuration provided an average energy resolution of 19.6 % and the image resolution ranges was 1.5 to 2.3 mm in radial direction. The sensitivity of the miniPET was 1.08 cps/kBq as determined using a point source. In addition, results of rat brain scan performed with FDG are given to characterize imaging capability of the system. The displayed data document that the miniPET scanner supports good quality brain imaging of small animals

• Ethernet based distributed data acquisition system for a small animal PET

  Authors: G. Hegyesi, J. Imrek, G. Kalinka, J Molnar, D. Novak, J. Vegh, L Balkay, M Emri, A. Kis, G. Molnar, L. Tron, I. Valastyan, I. Bagamery, T. Bukki, S. Rozsa, Z. Szabo, A. Kerek

  Real Time Conference, 2005. 14th IEEE-NPSS; 07/2005

  We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. EachWe report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8×8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer and digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system, coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and it generates a time stamp with a coincidence resolution of 2 to 3 ns. The data acquisition System is based on Ethernet network and is highly scalable in size and performance.

• Development of an FPGA-based data acquisition module for small animal PET

  Authors: G. Hegyesi, J. Imrek, G. Kalinka, J. Molnar, D. Novak, J. Vegh, L. Balkay, M. Emri, G. Molnar, L. Tron, I. Bagamery, T. Bukki, S. Rozsa, Z. Szabo, A. Kerek

  Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004

  We report on the design of a DAQ module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is built up from strictlyWe report on the design of a DAQ module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is built up from strictly identical DAQ modules, and which has no built-in hardware limitation on the maximum number of modules. The developed DAQ module comprises of an LSO scintillator crystal block, a position sensitive PMT, analog signal conditioning circuits, a digitizer, an FPGA for digital signal processing and a communication module through which the collected data is sent to a cluster of computers for post processing and storage. Instead of implementing hardware coincidence detection between the modules we attach a precise time-stamp to each event in our design, and the coincidence is determined by the data collecting computers during the post processing. The digital CFD algorithm implemented in the FPGA gives a time resolution of 2 to 3 ns FWHM for real detector signals

• Database management expert program for integrated evaluation of non-invasive and invasive results of coronary heart disease

  Authors: Zs. Koszegi, E. Balogh, L. Balkay, J. Varga, L. Galuska, Cs. Jenei, D. Apro, I. Edes

  Computers in Cardiology, 2003; 10/2003

  The coronary angiography giving the morphological data of epicardiac coronary stenoses and non-invasive tests sometimes even together are insufficient for evaluating the functional consequences ofThe coronary angiography giving the morphological data of epicardiac coronary stenoses and non-invasive tests sometimes even together are insufficient for evaluating the functional consequences of the epicardiac coronary stenoses. However, catheterisation allows us to detect the blunting of coronary flow increase during maximal vasodilatation (coronary flow reserve, CFR, e.g. by Doppler flow wire) and by measuring the translesional pressure gradient by pressure wire (fractional flow reserve, FFR) providing accurate functional assessment. According to this concept the authors have developed a complex cardiac database management program (Holistic Coronary Care, HCC). The database has been built on client-server technology where the central object is the 16-segment polar map. The system contains contextual and graphical elements for a quick data entry. By the assessment of 16 left ventricular segments on a polar map display there is a possibility for direct comparison of the invasive functional and morphologic and the non-invasive functional data. Details measured by pressure or Doppler wire are also stored in the coronary evaluating unit and the coronary segments are rendered to the supplied left ventricular segments. For the correct indication of coronary interventions (from functional and financial point of view) it is important to verify unambiguously the functionally significant coronary stenoses. To the best of our knowledge, the necessity of percutan or surgical intervention can be decided the most accurately by FFR and CFR, furthermore CFR objectively shows the failure of the coronary microvasculature.

• [The effect of a single-dose intravenous vinpocetine on brain metabolism in patients with ischemic stroke]

  Authors: B Gulyás, P Bönöczk, A Vas, L Csiba, D Bereczki, I Boros, S Szakáll, L Balkay, M Emri, I Fekete, L Galuska, L Kerényi, S Lehel, T Márián, T Molnár, J Varga, L Trón

  Orvosi hetilap. 04/2001; 142(9):443-9.

  The effect of a single-dose i.v. infusion of vinpocetine on the cerebral blood flow (CBF) and glucose metabolism of post-stroke patients was studied by measuring the regional and global cerebralThe effect of a single-dose i.v. infusion of vinpocetine on the cerebral blood flow (CBF) and glucose metabolism of post-stroke patients was studied by measuring the regional and global cerebral metabolic rates of glucose (CMRglu) and the corresponding kinetic constants before and after treatment. Transcranial Doppler (TCD) and single photon emission tomography (SPECT) measurements were also performed. The cerebral glucose metabolism was significantly higher in the contralateral hemisphere than in the affected one before therapy. In the affected hemisphere the regional glucose metabolism was inhomogenous: relatively low values were measured in the stroke region, whereas it was increased in the peristroke region. Although a single-dose vinpocetine treatment did not affect significantly the regional or global metabolic rates of glucose, the glucose transport (both intracellular up-take and release) was strongly affected in the whole brain, in the contralateral hemisphere and in the peri-infarct area of the symptomatic hemisphere. A slightly increased (not significant, N. S.) cerebral blood flow could be observed in the contralateral and a decreased flow (N. S.) in the symptomatic hemisphere.

• Hypoglycemia activates compensatory mechanism of glucose metabolism of brain.

  Authors: T Márián, L Balkay, I Fekete, Z Lengyel, G Veress, O Esik, L Trón, Z Krasznai

  Acta biologica Hungarica. 02/2001; 52(1):35-45.

  The effect of plasma glucose concentration on the cerebral uptake of [18F]-fluorodeoxy-D-glucose (FDG) was studied in a broad concentration range in a rabbit brain model using dynamic FDG PETThe effect of plasma glucose concentration on the cerebral uptake of [18F]-fluorodeoxy-D-glucose (FDG) was studied in a broad concentration range in a rabbit brain model using dynamic FDG PET measurements. Hypoglycemic and hyperglycemic conditions were maintained by manipulating plasma glucose applying i.v. glucose or insulin load. FDG utilization (K) and cerebral glucose metabolic rate (CGMR) were evaluated in a plasma glucose concentration range between 0.5 mM and 26 mM from the kinetic constant k1, k2, k3 obtained by the Sokoloff model of FDG accumulation. A decreasing set of standard FDG uptake values found with increasing blood glucose concentration was explained by competition between the plasma glucose and the radiopharmacon FDG. A similar trend was observed for the forward kinetic constants k1, and k3 in the entire concentration range studied. The same decreasing tendency of k2 was of a smaller magnitude and was reverted at the lowest glucose concentrations where a pronounced decrease of this backward transport rate constant was detected. Our kinetic data indicate a modulation of the kinetics of carbohydrate metabolism by the blood glucose concentration and report on a special mechanism compensating for the low glucose supply under conditions of extremely low blood glucose level.

• Membrane permeability changes induce hyperpolarization in transformed lymphoid cells under high-density culture conditions.

  Authors: T Márián, L Balkay, Z Krasznai, L Trón

  Cytometry. 12/2000; 41(3):186-92.

  BACKGROUND: Membrane potential changes in cells from the human lymphoid B cell line, JY, evoked by increasing cell density in culture were investigated, as data published on other cell types areBACKGROUND: Membrane potential changes in cells from the human lymphoid B cell line, JY, evoked by increasing cell density in culture were investigated, as data published on other cell types are controversial. An attempt was also made to clear the underlying mechanism. METHODS: Nonadherent JY cells were isolated from high-density plateau-phase cultures (type A cells), medium-density log-phase cultures (type B cells), and low-density lag-phase cultures (type C cells). They were analyzed for transmembrane potential, intracellular free concentration of potassium and sodium, membrane permeability for monovalent cations, cell cycle distribution by measuring DNA content, and glucose uptake. RESULTS: C type cells proved to be relatively depolarized (-41 +/- 3 mV) and cells obtained from the highest density cultures hyperpolarized (-60 +/- 3 mV). Intracellular concentrations ([K](i) = 92-97 mM and [Na](i) = 34-35 mM) were almost identical for each type of cell. The sodium/potassium permeability constant ratio in the A and C type of cells was 0.047 and 0.094, respectively. High-density culture conditions resulted in a pronounced G(1)-phase arrest. CONCLUSIONS: Differences in the membrane potential values induced by high-density culture conditions were maintained by changes in the membrane permeability for the monovalent cations.

• [Comparative analysis of quantifying methods in FDG-PET scans of the brain]

  Authors: Z Krasznai, L Balkay, L Trón

  Orvosi hetilap. 10/2000; 141(36):1959-65.

  The comparative analysis of three tracer kinetic methods most frequently applied for the quantization of the results of FDG-PET-brain scans was performed. The data of measurements on five healthyThe comparative analysis of three tracer kinetic methods most frequently applied for the quantization of the results of FDG-PET-brain scans was performed. The data of measurements on five healthy patients were evaluated by the most general method developed by Phelps, the Patlak-procedure and the SUV- (standard uptake value) method. It was demonstrated by the aid of correlation analysis that the applicability of the results of the more simple methods to estimate glucose metabolic rate (GMR) as calculated by the Phelps-method depended on the kind of the selected region of the brain. It was shown that the most considerable distortion occurred in the case of the same anatomical regions of the brain with both simplified methods. These regions were located either in the white matter or in the vicinity of larger size blood vessels or they were elements of the base of the skull [gyrus rectus (l. u.), pons, capsula interna (l. u.), cerebellum (l. u.), corpus callosum]. The distorted estimation is explained by the fact that the simpler models neglect dephosphorylation of the FDG-6P, and they also disregard the contribution of the intravascular activity to the tissue radioactivity as determined by the relatively low resolution PET measurement. The correlation coefficient between the GMR as calculated by the Phelps-method and glucose consumption data by the investigated simpler methods had very low values for regions located in the white matter, eventual close to blood vessels or being elements of the base of the skull.

• Membrane hyperpolarization removes inactivation of Ca2+ channels, leading to Ca2+ influx and subsequent initiation of sperm motility in the common carp.

  Authors: Z Krasznai, T Marian, H Izumi, S Damjanovich, L Balkay, L. Tron, M Morisawa

  Proceedings of the National Academy of Sciences of the United States of America. 03/2000; 97(5):2052-7.

  Change of osmolality surrounding spawned sperm from isotonic to hypotonic causes the initiation of sperm motility in the common carp. Here we show that membrane-permeable cAMP does not initiateChange of osmolality surrounding spawned sperm from isotonic to hypotonic causes the initiation of sperm motility in the common carp. Here we show that membrane-permeable cAMP does not initiate motility of carp sperm that is quiescent in isotonic solution, and that motility of the demembranated sperm can be reactivated without cAMP. Furthermore, the cAMP level does not change during the initiation of sperm motility, and inhibitors of protein kinase do not affect sperm motility, suggesting that no cAMP-dependent system is necessary for the regulation of sperm motility. Sperm motility could not be initiated in Ca(2+)-free hypoosmotic solutions, and significant increase in the intracellular Ca(2+) level was observed by a Ca-sensitive fluorescence dye during hypoosmolality-induced active motion period. The demembranated sperm cells were fully reactivated in the solutions containing 10(-7) to 10(-5) M Ca(2+). Ca(2+) channel blockers such as verapamil and omega-conotoxin reversibly inhibited the initiation of sperm motility, suggesting that Ca(2+) influx is the prerequisite for the initiation of carp sperm motility. Motility of intact sperm was completely blocked; however, that of the demembranated sperm was not inhibited by the calmodulin inhibitor W7, suggesting that the calmodulin bound close to the plasma membrane participated in the initiation of sperm motility. Flow cytometric membrane potential measurements and spectrophotometric measurements by using fluorescence dyes showed transient membrane hyperpolarization on hypoosmolality-induced motility. This article discusses the role of membrane hyperpolarization on removal of inactivation of Ca(2+) channels, leading to Ca(2+) influx at the initiation of carp sperm motility.

• [Evaluation of the nature of brain tumors using methods of nuclear medicine]

  Authors: E Ambrus, A Kuncz, G Jánoki, E Vörös, S Szakáll, L Balkay, M Emri, L Trón, M Bodosi, L Csernay, L Pávics

  Orvosi hetilap. 10/1999; 140(36):1979-83.

  FDG-PET studies permit an assessment of the degree of brain tumour malignancy and detection of tumour recurrence. MIBI-SPECT also affords promising results in this respect. In this work, theFDG-PET studies permit an assessment of the degree of brain tumour malignancy and detection of tumour recurrence. MIBI-SPECT also affords promising results in this respect. In this work, the diagnostic value of MIBI-SPECT was compared with that of FDG-PET for the determination of primary brain tumours malignancy and the detection of recurrent brain tumours. SPECT and PET examination were carried out within a week in 14 patients (12 males, 2 females, mean age: 40 years, range 16-61 years) with brain tumours. Seven patients had a primary tumour, and in a further 7 MRI or the clinical signs and symptoms let to a suspicion of tumour recurrence. All tumours were verified histologically to be gliomas of grades I-IV. The SPECT and PET images were analysed visually and semiquantitatively. In 3 of the investigated 7 primary glioma patients, there was a visibly enhanced MIBI-positive cases, only one had an increased FDG uptake. In 4 of the 7 tumour recurrence cases, either the MIBI or the FDG uptake was visibly increased. All of these were histologically high-grade gliomas. In the remaining low grade tumours (primary of recurrent), neither MIBI nor FDG revealed a pathologically increased uptake. The intensity of radiopharmaceutical uptake at the site of the tumours was visually and semiquantitatively higher for MIBI that for FDG. It is concluded that MIBI-SPECT is a valuable and simple tool for evaluation of the biological characteristics of brain tumours, showing increased uptake of MIBI according to the malignancy and tumour recurrence of brain tumours.

• Preparation and primary evaluation of [11C]CSC as a possible tracer for mapping adenosine A2A receptors by PET.

  Authors: T Márián, I Boros, Z Lengyel, L Balkay, G Horváth, M Emri, E Sarkadi, A J Szentmiklósi, I Fekete, L Trón

  Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine. 06/1999; 50(5):887-93.

  A 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine andA 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine and [11C]methyl iodide. The decay-corrected radiochemical yield was 32.3% with a radiochemical purity of 99%, a specific activity of 1.85-5.55 GBq/mumol and a preparation time of 1 h. A primary evaluation of [11C]CSC as a potential tracer for mapping adenosine A2A receptors by positron emission tomography (PET) is also presented. Biodistribution and autoradiographic studies were carried out on Swiss mice and domestic rabbits. In mice the lung showed the highest uptake at 10 min after i.v. injection, followed by the liver, kidney, heart and brain. Inside the brain a high level of radioactivity accumulated in the striatum, in accordance with previous findings on the specific spatial distribution of A2A adenosine receptors and also in the medulla oblongata. Dynamic PET studies on rabbits showed a fast brain uptake of CSC, reaching a maximum in less then 2 min. On the basis of competition experiments with the unlabeled ligand [11C]CSC proves to bind specifically to the appropriate receptor.

• Cerebral effects of a single dose of intravenous vinpocetine in chronic stroke patients: a PET study.

  Authors: S Szakáll, I Boros, L Balkay, M Emri, I Fekete, L Kerényi, S Lehel, T Márián, T Molnár, J Varga, L Galuska, L Trón, D Bereczki, L Csiba, B Gulyás

  Journal of neuroimaging : official journal of the American Society of Neuroimaging. 11/1998; 8(4):197-204.

  The effects of vinpocetine (Cavinton) on the cerebral glucose metabolism of chronic stroke patients are studied with positron emission tomography. The regional and global cerebral metabolic rates ofThe effects of vinpocetine (Cavinton) on the cerebral glucose metabolism of chronic stroke patients are studied with positron emission tomography. The regional and global cerebral metabolic rates of glucose (CMRglu) and the kinetic constants related to them are quantified before and after single-dose intravenous vinpocetine treatment. These measurements are completed with transcranial Doppler sonography and single photon emission computed tomography to explore the possible mechanisms underlying the resulting changes in glucose uptake and metabolism in the brain. The authors' findings indicate that a single-dose vinpocetine treatment, although it does not affect significantly the regional or global metabolic rates of glucose, improves significantly the transport of glucose (both uptake and release) through the blood-brain barrier in the whole brain, the entire contralateral hemisphere, and in the brain tissue around the infarct area of the symptomatic hemisphere. These changes are in accord with increased blood flow in the entire contralateral hemisphere as well as decreased blood flow velocity and increased peripheral vessel resistance in the entire symptomatic hemisphere.

• Polar map interpretation of coronarography, echocardiography and SPECT for “holistic” evaluation of cardiological investigations

  Authors: Z. Koszegi, L. Balkay, L. Galuska, T. Fulop, L. Velok, T. Szuk, I. Voith, I. Hegedus, I. Edes

  Computers in Cardiology 1998; 10/1998

  Access (Microsoft Office)-based software was developed to register the results of different cardiological investigations (echocardiography, coronarography and SPECT) in 16 left ventricular segmentsAccess (Microsoft Office)-based software was developed to register the results of different cardiological investigations (echocardiography, coronarography and SPECT) in 16 left ventricular segments in a polar map display in order to compare the anatomical and functional data. Ten patients with previous myocardial infarction were selected (mean age: 48 years, EF: 36.1±7.2%). They had 14 totally or subtotally occluded coronary branches. The overlap between the occlusion-associated regions derived by angiography and the corresponding defects on MIBI SPECT, and also the echocardiographic segmental wall motion scores were evaluated. The distribution of the total of 160 segments with rest perfusion defects on MIBI SPECT and the wall motion abnormalities detected by echocardiogaphy gave positive and negative predictive values of coronary occlusion of 0.94 and 0.81 against SPECT and 0.82 and 0.76 against echocardiography, respectively. Further analysis revealed that the relative MIBI activities of the individual segments correlated significantly with the wall motion scores (r=-0.87). It is concluded that the direct comparison of tomographic imaging and echocardiography with the angiogram on the polar map display in order to measure the functional consequences of coronary artery disease may help to indicate an intervention on an individual coronary lesion

• [11C-methionine: an effective radio-tracer for PET scan in the detection of tumors of low proliferating capacity]

  Authors: L Trón, O Esik, Z Kovács, E Sarkadi, L Galuska, L Balkay, M Emri, T Molnár, S Szakáll, E Tóth, T Márián

  Orvosi hetilap. 09/1997; 138(34):2107-12.

  11C-methyl-methionine is available at the PET Center of University Medical School Debrecen since June, 1996. The first 5 oncological examinations were indicated for clinically suspected11C-methyl-methionine is available at the PET Center of University Medical School Debrecen since June, 1996. The first 5 oncological examinations were indicated for clinically suspected recurrent/residual tumorous tissue of low-grade/low proliferative capacity, following the negative or inconclusive results of previous 18F-deoxyglucose (FDG) examinations. In these situations, the methionine examinations provided conclusive results in 4 cases (out of the total of 5 examinations). On the basis of published data and own experience, the authors recommend methionine PET investigations for diagnosis, differential diagnosis and therapy monitoring of tumours of low-grade/low proliferative capacity following inconclusive results of previous FDG examination.