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Gian Luigi Lenzi – One of the best experts on this subject based on the ideXlab platform.

  • Motor Activation by single-photon emission computed tomography. A comparison of xenon-133 and technetium-99m HM-PAO “split-dose” methods.
    Journal of neuroimaging : official journal of the American Society of Neuroimaging, 1993
    Co-Authors: V. Di Piero, Patrizia Pantano, Monica Ricci, Gian Luigi Lenzi
    Abstract:

    Single-photon emission computed tomography (SPECT) was used to investigate the feasibility of the technetium 99m-hexamethylpropyleneamineoxime ( 99mTc HM-PAO) split-dose method to evidence changes in regional cerebral blood flow during a motor Activation Task, in comparison with a quantitative method using the inhalatory xenon-133. Four subjects were studied twice with both methods, at rest and during finger opposition movements. On the activated cerebral hemisphere, a significant increase in regional cerebral blood flow was observed over the motor cortical areas. The average increases were +28.1 +/- 5.6% for the xenon-133 method and +12.3 +/- 5.2% for the 99mTc HM-PAO method. By using the linearization algorithm for the 99mTc HM-PAO method, a mean increase of +22.5 +/- 8.9% was calculated. This study demonstrated that the split-dose method allows the motor Activation SPECT studies with 99mTc HM-PAO to be done in a single session.

  • Motor stimulation response by technetium-99m hexamethylpropylene amine oxime split-dose method and single photon emission tomography
    European Journal of Nuclear Medicine, 1992
    Co-Authors: Patrizia Pantano, Monica Ricci, Vittorio Piero, Cesare Fieschi, Luigi Bozzao, Gian Luigi Lenzi
    Abstract:

    We applied the technetium-99m hexamethylpropylene amine oxime (^99mTc-HMPAO) split-dose method in order to evaluate the feasibility of assessing cerebral blood flow (CBF) changes with single photphoton emission tomography (SPET) during a motor Activation Task. Eleven normal subjects were studied using the Tomomatic 564 (Medimatic, DK). Five subjects were studied twice at rest and 6 subjects at rest and during a motor Task performance (finger opposition movements). A total of 28 mCi of ^99mTc-HMPAO was injected in 2 doses with a 1:3 ratio. The first scan was obtained after injection of 7 mCi at rest in all subjects. The second scan was obtained a few minutes later, after injection of the remaining dose (21 mCi), under similar resting conditions or during a motor Task performance. The mean brain uptake was proportional to the amount of tracer injected and to the acquisition time for both the first scan (5263±1266 counts × mCi × min) and the second (5034.4±966 counts × mCi × min). The grey/white matter ratio was 1.67±0.019 and 1.67±0.097 for the two scans, respectively. A three-way analysis of variance (ANOVA) for repeated measure showed no significant effects of side, slice and region of interest (ROI) on the CBF in the 5 subjects studied twice at rest, and the mean regional CBF change was −0.2%±5%. In the 6 subjects studied at rest and during motor Activation, the image subtsubtraction analysis showed a significant CBF increase in the primary motor cortex contralateral to the stimulated side (15%±7%, n =6) and medially in the supplementary motor area (22%±12%, n =4). Our results indicate that the split-dose method allows the detection of a local CBF response to motor Activation using ^99mTc-HMPAO in a single imaging session.

Georg Grön – One of the best experts on this subject based on the ideXlab platform.

  • regional brain Activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention deficit hyperactivity disorder
    Human Brain Mapping, 2009
    Co-Authors: Robert Christian Wolf, Michael M. Plichta, Fabio Sambataro, Andreas J. Fallgatter, Christian Jacob, Klaus-peter Lesch, Martin J. Herrmann, Carlos Schonfeldtlecuona, Bernhard J Connemann, Georg Grön
    Abstract:

    Previous studies on working memory (WM) function in adults with attention-deficit/hyperactiv- ity disorder (ADHD) suggested aberrant Activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that Activation differences in these regions most likely reflect aberrant frontocerebel- lar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resoresonanceging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional Activation changes and functional con- nectivity differences during cognitive processing in healthy controls (n 5 12) and ADHD adults (n 5 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the Activation Task, however, ADHD patients showed significantly less Activation in the left ventrolateral prefprefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent com- ponent analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingu- late regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingu- late cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain Activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing. Hum Brain Mapp 30:2252-2266, 2009. V C 2008 Wiley-Liss, Inc.

  • regional brain Activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention deficit hyperactivity disorder
    Human Brain Mapping, 2009
    Co-Authors: Robert Christian Wolf, Michael M. Plichta, Fabio Sambataro, Andreas J. Fallgatter, Christian Jacob, Klaus-peter Lesch, Martin J. Herrmann, Carlos Schonfeldtlecuona, Bernhard J Connemann, Georg Grön
    Abstract:

    Previous studies on working memory (WM) function in adults with attention-deficit/hyperactivity disorder (ADHD) suggested aberrant Activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that Activation differences in these regions most likely reflect aberrant frontocerebellar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resoresonanceging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional Activation changes and functional connectivity differences during cognitive processing in healthy controls (n = 12) and ADHD adults (n = 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the Activation Task, however, ADHD patients showed significantly less Activation in the left ventrolateral prefprefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent component analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingulate regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingulate cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain Activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing.

Patrizia Pantano – One of the best experts on this subject based on the ideXlab platform.

  • Motor Activation by single-photon emission computed tomography. A comparison of xenon-133 and technetium-99m HM-PAO “split-dose” methods.
    Journal of neuroimaging : official journal of the American Society of Neuroimaging, 1993
    Co-Authors: V. Di Piero, Patrizia Pantano, Monica Ricci, Gian Luigi Lenzi
    Abstract:

    Single-photon emission computed tomography (SPECT) was used to investigate the feasibility of the technetium 99m-hexamethylpropyleneamineoxime ( 99mTc HM-PAO) split-dose method to evidence changes in regional cerebral blood flow during a motor Activation Task, in comparison with a quantitative method using the inhalatory xenon-133. Four subjects were studied twice with both methods, at rest and during finger opposition movements. On the activated cerebral hemisphere, a significant increase in regional cerebral blood flow was observed over the motor cortical areas. The average increases were +28.1 +/- 5.6% for the xenon-133 method and +12.3 +/- 5.2% for the 99mTc HM-PAO method. By using the linearization algorithm for the 99mTc HM-PAO method, a mean increase of +22.5 +/- 8.9% was calculated. This study demonstrated that the split-dose method allows the motor Activation SPECT studies with 99mTc HM-PAO to be done in a single session.

  • Motor stimulation response by technetium-99m hexamethylpropylene amine oxime split-dose method and single photon emission tomography
    European Journal of Nuclear Medicine, 1992
    Co-Authors: Patrizia Pantano, Monica Ricci, Vittorio Piero, Cesare Fieschi, Luigi Bozzao, Gian Luigi Lenzi
    Abstract:

    We applied the technetium-99m hexamethylpropylene amine oxime (^99mTc-HMPAO) split-dose method in order to evaluate the feasibility of assessing cerebral blood flow (CBF) changes with single photon emission tomography (SPET) during a motor Activation Task. Eleven normal subjects were studied using the Tomomatic 564 (Medimatic, DK). Five subjects were studied twice at rest and 6 subjects at rest and during a motor Task performance (finger opposition movements). A total of 28 mCi of ^99mTc-HMPAO was injected in 2 doses with a 1:3 ratio. The first scan was obtained after injection of 7 mCi at rest in all subjects. The second scan was obtained a few minutes later, after injection of the remaining dose (21 mCi), under similar resting conditions or during a motor Task performance. The mean brain uptake was proportional to the amount of tracer injected and to the acquisition time for both the first scan (5263±1266 counts × mCi × min) and the second (5034.4±966 counts × mCi × min). The grey/white matter ratio was 1.67±0.019 and 1.67±0.097 for the two scans, respectively. A three-way analysis of variance (ANOVA) for repeated measure showed no significant effects of side, slice and region of interest (ROI) on the CBF in the 5 subjects studied twice at rest, and the mean regional CBF change was −0.2%±5%. In the 6 subjects studied at rest and during motor Activation, the image subtraction analysis showed a significant CBF increase in the primary motor cortex contralateral to the stimulated side (15%±7%, n =6) and medially in the supplementary motor area (22%±12%, n =4). Our results indicate that the split-dose method allows the detection of a local CBF response to motor Activation using ^99mTc-HMPAO in a single imaging session.

Manuel Dujovny – One of the best experts on this subject based on the ideXlab platform.

Robert Christian Wolf – One of the best experts on this subject based on the ideXlab platform.

  • regional brain Activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention deficit hyperactivity disorder
    Human Brain Mapping, 2009
    Co-Authors: Robert Christian Wolf, Michael M. Plichta, Fabio Sambataro, Andreas J. Fallgatter, Christian Jacob, Klaus-peter Lesch, Martin J. Herrmann, Carlos Schonfeldtlecuona, Bernhard J Connemann, Georg Grön
    Abstract:

    Previous studies on working memory (WM) function in adults with attention-deficit/hyperactiv- ity disorder (ADHD) suggested aberrant Activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that Activation differences in these regions most likely reflect aberrant frontocerebel- lar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resonance imaging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional Activation changes and functional con- nectivity differences during cognitive processing in healthy controls (n 5 12) and ADHD adults (n 5 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the Activation Task, however, ADHD patients showed significantly less Activation in the left ventrolateral prefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent com- ponent analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingu- late regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingu- late cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain Activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing. Hum Brain Mapp 30:2252-2266, 2009. V C 2008 Wiley-Liss, Inc.

  • regional brain Activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention deficit hyperactivity disorder
    Human Brain Mapping, 2009
    Co-Authors: Robert Christian Wolf, Michael M. Plichta, Fabio Sambataro, Andreas J. Fallgatter, Christian Jacob, Klaus-peter Lesch, Martin J. Herrmann, Carlos Schonfeldtlecuona, Bernhard J Connemann, Georg Grön
    Abstract:

    Previous studies on working memory (WM) function in adults with attention-deficit/hyperactivity disorder (ADHD) suggested aberrant Activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that Activation differences in these regions most likely reflect aberrant frontocerebellar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resonance imaging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional Activation changes and functional connectivity differences during cognitive processing in healthy controls (n = 12) and ADHD adults (n = 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the Activation Task, however, ADHD patients showed significantly less Activation in the left ventrolateral prefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent component analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingulate regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingulate cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain Activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing.