Academic literature on the topic 'Hypercapnia fMRI'
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Journal articles on the topic "Hypercapnia fMRI"
Cohen, Eric R., Kamil Ugurbil, and Seong-Gi Kim. "Effect of Basal Conditions on the Magnitude and Dynamics of the Blood Oxygenation Level-Dependent fMRI Response." Journal of Cerebral Blood Flow & Metabolism 22, no. 9 (September 2002): 1042–53. http://dx.doi.org/10.1097/00004647-200209000-00002.
Full textPeng, Shin-Lei, Harshan Ravi, Min Sheng, Binu P. Thomas, and Hanzhang Lu. "Searching for a truly “iso-metabolic” gas challenge in physiological MRI." Journal of Cerebral Blood Flow & Metabolism 37, no. 2 (July 20, 2016): 715–25. http://dx.doi.org/10.1177/0271678x16638103.
Full textBasile, Miriam, Simone Cauzzo, Alejandro Luis Callara, Domenico Montanaro, Valentina Hartwig, Maria Sole Morelli, Francesca Frijia, et al. "mICA-Based fMRI Analysis of Specific CO2-Level-Dependent BOLD Signal Changes in the Human Brainstem." Electronics 12, no. 2 (January 6, 2023): 290. http://dx.doi.org/10.3390/electronics12020290.
Full textEnglund, Erin K., Maria A. Fernández-Seara, Ana E. Rodríguez-Soto, Hyunyeol Lee, Zachary B. Rodgers, Marta Vidorreta, John A. Detre, and Felix W. Wehrli. "Calibrated fMRI for dynamic mapping of CMRO2 responses using MR-based measurements of whole-brain venous oxygen saturation." Journal of Cerebral Blood Flow & Metabolism 40, no. 7 (August 8, 2019): 1501–16. http://dx.doi.org/10.1177/0271678x19867276.
Full textUh, J., F. Xu, U. Yezhuvath, Y. Cheng, H. Gu, Y. Yang, and H. Lu. "The Effect of Hypercapnia on Resting State fMRI." NeuroImage 47 (July 2009): S185. http://dx.doi.org/10.1016/s1053-8119(09)72046-4.
Full textAndrade, Katia C., Octavio M. Pontes-Neto, Joao P. Leite, Antonio Carlos Santos, Oswaldo Baffa, and Draulio B. de Araujo. "Quantitative aspects of brain perfusion dynamic induced by BOLD fMRI." Arquivos de Neuro-Psiquiatria 64, no. 4 (December 2006): 895–98. http://dx.doi.org/10.1590/s0004-282x2006000600001.
Full textKruuse, Christina, Adam E. Hansen, Henrik BW Larsson, Martin Lauritzen, and Egill Rostrup. "Cerebral Haemodynamic Response or Excitability is not Affected by Sildenafil." Journal of Cerebral Blood Flow & Metabolism 29, no. 4 (February 11, 2009): 830–39. http://dx.doi.org/10.1038/jcbfm.2009.10.
Full textXu, Feng, Jinsoo Uh, Matthew R. Brier, John Hart, Uma S. Yezhuvath, Hong Gu, Yihong Yang, and Hanzhang Lu. "The Influence of Carbon Dioxide on Brain Activity and Metabolism in Conscious Humans." Journal of Cerebral Blood Flow & Metabolism 31, no. 1 (September 15, 2010): 58–67. http://dx.doi.org/10.1038/jcbfm.2010.153.
Full textWang, Xiao, Xiao-Hong Zhu, Yi Zhang, and Wei Chen. "Large Enhancement of Perfusion Contribution on fMRI Signal." Journal of Cerebral Blood Flow & Metabolism 32, no. 5 (March 7, 2012): 907–18. http://dx.doi.org/10.1038/jcbfm.2012.26.
Full textChen, J. Jean, and G. Bruce Pike. "Global Cerebral Oxidative Metabolism during Hypercapnia and Hypocapnia in Humans: Implications for BOLD fMRI." Journal of Cerebral Blood Flow & Metabolism 30, no. 6 (April 7, 2010): 1094–99. http://dx.doi.org/10.1038/jcbfm.2010.42.
Full textDissertations / Theses on the topic "Hypercapnia fMRI"
Pastorello, Bruno Fraccini. "Em busca da região epileptiforme em pacientes com epilepsia do lobo temporal: métodos alternativos baseados em fMRI e EEG-fMRI." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-26102011-135335/.
Full textTemporal lobe epilepsy (TLE) is the most common and resistant form of epilepsy to anti-epileptic drug. There are several types of anti-epileptic drugs used in seizure control. However, in some cases drug treatment is not effective and surgery to remove the epileptogenic zone (EZ) is a recommended alternative. EZ is a theoretical concept and there are many techniques that have been applied to enclose it precisely. In practice, EEG, video-EEG, MEG, SPECT, PET and various MRI techniques, especially functional MRI (fMRI), have been used to map areas related to EZ. However, in some cases, the results remain non-convergent and the EZ, undefined. Therefore, the use of new methodologies to assist the location of EZ have been proposed. Herein, our goal was to develop two methods for assessing the EZ. The first one was designed to access changes in the hemodynamic response (HRF) of the EZ in response to hypercapnia. 22 patients with TLE and 10 normal volunteers were evaluated by modulating the partial pressure of CO2 during the acquisition of fMRI in a breathing holding and a passive inhalation CO2/air protocols. The results show increased onset times and decreased amplitude of the HRF in the temporal lobe of TLE patients compared with asymptomatic volunteers. Moreover, most patients had onset maps coincident with ictal SPECT localizations. The second proposed study was based on simultaneous EEG-fMRI acquisitions. The relationship between powers of alpha and theta bands (EEG) and BOLD contrast (fMRI) was investigated in 41 TLE patients and 7 healthy controls. Alpha band results show a consistent negative correlation in the occipital, parietal and frontal lobes both in controls and TLE patients. In addition, controls show disperse positive correlations in both hemispheres. On the other hand, TLE patients presented strong positive correlations in the thalamus and insula. Theta band analysis, in controls, primarily show positive correlations in bilateral pre-and post-central gyri. In patients, robust positive correlations were observed in the anterior cingulate gyrus, thalamus, insula, putamen, superior parietal, frontal and temporal gyri. Moreover, the lateralization index (LI) indicates a coincidence between the side of the EZ evaluated by clinical diagnosis and clusters detected in the theta band. In conclusion, the hipercapnia study showed to be an interesting tool in locating EZ and the results are similar to SPECT findings. The longer onset and lower amplitude of the HRF observed in patients may be related to a vascular stress due to the recurrence of seizures. Furthermore, alpha and theta rhythms may be a promising tool to be used in determining the lateralization of EZ in patients with TLE.
CHENG, YU-CHIA, and 鄭右佳. "FMRI in Hypercapnia : Multiple Resting State Network Functional Connectivity Change." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/ued9mb.
Full text逢甲大學
生醫資訊暨生醫工程碩士學位學程
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In many studies of Resting State Functional Magnetic Resonance Imaging (RS-fMRI), it has been shown that neurons in the human brain have spontaneous activity in the resting state and produce signals of low frequency response. Some spontaneous physiological state changes in the resting state are considered to be reflected in the signal changes of the resting state functional magnetic resonance imaging. Blood Oxygenation Level-Dependent (BOLD) is a measure of the change in oxygen content in the blood vessels of the brain caused by neuronal activity. Related studies have found that the BOLD signal obtained by functional magnetic resonance imaging has been It has been shown to change due to differences in the concentration of carbon dioxide (CO2) in the blood. In this study, we used a gas with different concentrations of carbon dioxide to cause changes in the concentration of carbonic acid in the blood, to observe changes in the connected network of the brain at rest, and to use the volume change and graphical theory for correlation analysis. Studies have shown that some connected networks in the brain are associated with physiological responses to changes in the concentration of carbonic acid in the blood, such as areas associated with pain perception that have significant changes in response volume and network performance.
Lajoie, Isabelle. "Magnetic resonance imaging of resting cerebral oxygen metabolism : applications in Alzheimer’s disease." Thèse, 2017. http://hdl.handle.net/1866/19332.
Full textLe contraste BOLD employé dans les études d’imagerie par résonance magnétique fonctionnelle (IRMf) provient d’une combinaison ambigüe de changements du flux sanguin cérébral, du volume sanguin ainsi que du métabolisme oxydatif. Dans un contexte où les fonctions vasculaires ou métaboliques du cerveau ont pu être affectées, tel qu’avec l’âge ou certaines maladies, il est crucial d’effectuer une décomposition du signal BOLD en composantes physiologiquement plus spécifiques. La dernière génération de méthodes d’IRMf calibrée permet d’estimer à la fois le flux sanguin cérébral et le métabolisme oxydatif au repos. Le présent travail est basé sur une telle technique, appelée QUantitative O2 (QUO2), qui, via un model généralisé, prend en considération les changements du flux sanguin ainsi que ceux en concentrations sanguine d’O2 durant des périodes d’hypercapnie et d’hyperoxie, afin d’estimer, à chaque voxel, la fraction d’extraction d’oxygène et le métabolisme oxydatif au repos. Dans la première partie de cette thèse, le protocole d’acquisition ainsi que la stratégie d’analyse de l’approche QUO2 ont été revus afin d’améliorer la stabilité temporelle des réponses BOLD et du flux sanguin, conséquemment, afin d’accroître la fiabilité des paramètres estimés. Par la suite, une évaluation de la variabilité intra- et inter-sujet des différentes mesures QUO2 a été effectuée auprès d’un groupe de participants sains. En parallèle, une analyse de la sensibilité du model à différentes sources d’erreurs aléatoires (issues des mesures acquises) et systématiques (dues aux assomptions du model) a été réalisée. De plus, les impacts du niveau d’oxygène administré durant les périodes d’hyperoxie ont été évalués via une simulation puis expérimentalement, indiquant qu’une hyperoxie moyenne était bénéfique. Finalement, l’influence de la maladie d’Alzheimer sur les changements vasculaires et métaboliques a été explorée pour la première fois en appliquant le protocole QUO2 à une cohorte de patients Alzheimer et à un groupe témoin du même âge. Des différences en terme de flux sanguin, fraction d’oxygène extraite, métabolisme oxydatif, et taux de relaxation transverse R2* au repos comme en réponse à l’hypercapnie, ont été identifiées au niveau du voxel, ainsi qu’au niveau de régions cérébrales vulnérables à la maladie d’Alzheimer. Une liste de limitations accompagnées de recommandations a été dressée en ce qui a trait au temps de transit différé, aux artéfacts de susceptibilité magnétique, de même qu’au défi que représente l’hypercapnie chez les personnes âgées ou atteintes de la maladie d’Alzheimer.
Conference papers on the topic "Hypercapnia fMRI"
Carp, Stefan A., Maria Angela Franceschini, David A. Boas, and Young R. Kim. "Evaluation of Cerebral Energy Demand during Graded Hypercapnia and Validation of Optical Blood Flow Measurements against ASL fMRI." In Biomedical Optics. Washington, D.C.: OSA, 2010. http://dx.doi.org/10.1364/biomed.2010.jma71.
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