Visualization of the frontotemporal language fibers by tractography combined with functional magnetic resonance imaging and magnetoencephalography

2007 ◽  
Vol 106 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Kyousuke Kamada ◽  
Tomoki Todo ◽  
Yoshitaka Masutani ◽  
Shigeki Aoki ◽  
Kenji Ino ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
Awake Surgery ◽  
Hemispheric Dominance ◽  
Dominant Hemisphere ◽  
Functional Magnetic Resonance ◽  
Accurate Identification ◽  
Generation Task ◽  
Language Functions

Object There is continuous interest in the monitoring of language function during tumor resection around the fron-totemporal regions of the dominant hemisphere. The aim of this study was to visualize language-related subcortical connections, such as the arcuate fasciculus (AF) by diffusion tensor (DT) imaging–based tractography. Methods Twenty-two patients with brain lesions adjacent to the AF in the frontotemporal regions of the dominant hemisphere were studied. The AF tractography was accomplished by placing initiation and termination sites (seed and target points) in the frontal and temporal regions, which were functionally identified by using functional magnetic resonance (fMR) imaging in conjunction with a verb generation task and magnetoencephalography (MEG) in conjunction with a reading task. The combination of fMR imaging and MEG data clearly demonstrated the hemispheric dominance of language functions, which was confirmed by an intracranial amobarbital test (Wada procedure). In all 22 patients, the authors were able to consistently visualize the AF by DT imaging–based tractography, using the functionally identified seed and target points and a fractional anisotropy value of 0.16. In two of 22 cases investigated, the functional information, including the results of AF tractography, fMR imaging, and MEG, was imported to a neuronavigation system and was validated by bipolar electric stimulation of the cortical and subcortical areas during awake surgery. The cortical stimulation to the gyrus that included the area of activation identified in fMR imaging with the language task evoked speech arrest, while the subcortical stimulation close to the AF reproducibly caused paranomia without speech arrest. Postoperative AF tractography showed that the distances between the stimulus points and the AF were within 6 mm. Conclusions The combination of these techniques facilitated accurate identification of the location of the AF and verification of the language fibers.

Dissociated expressive and receptive language functions on magnetoencephalography, functional magnetic resonance imaging, and amobarbital studies

2006 ◽  
Vol 104 (4) ◽  
pp. 598-607 ◽  
Author(s):  
Kyousuke Kamada ◽  
Fumiya Takeuchi ◽  
Shinya Kuriki ◽  
Tomoki Todo ◽  
Akio Morita ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Left Hemisphere ◽  
Receptive Language ◽  
Control Group ◽  
Low Grade ◽  
Temporal Region ◽  
Functional Magnetic Resonance ◽  
Categorization Task ◽  
Language Functions ◽  
Verb Generation

✓Dissociated language functions are largely invalidated by standard techniques such as the amobarbital test and cortical stimulation. Language studies in which magnetoencephalography (MEG) and functional magnetic resonance (fMR) imaging are used to record data while the patient performs lexicosemantic tasks have enabled researchers to perform independent brain mapping for temporal and frontal language functions (MEG is used for temporal and fMR imaging for frontal functions). In this case report, the authors describe a right-handed patient in whom a right-sided insular glioma was diagnosed. The patient had a right-lateralized receptive language area, but expressive language function was identified in the left hemisphere on fMR imaging–and MEG-based mapping. Examinations were performed in 20 right-handed patients with low-grade gliomas (control group) for careful comparison with and interpretation of this patient’s results. In these tests, all patients were asked to generate verbs related to acoustically presented nouns (verb generation) for fMR imaging, and to categorize as abstract or concrete a set of visually presented words consisting of three Japanese letters for fMR imaging and MEG. The most prominent display of fMR imaging activation by the verb-generation task was observed in the left inferior and middle frontal gyri in all participants, including the patient presented here. Estimated dipoles identified with the abstract/concrete categorization task were concentrated in the superior temporal and supramarginal gyri in the left hemisphere in all control patients. In this patient, however, the right superior temporal region demonstrated significantly stronger activations on MEG and fMR imaging with the abstract/concrete categorization task. Suspected dissociation of the language functions was successfully mapped with these two imaging modalities and was validated by the modified amobarbital test and the postoperative neurological status. The authors describe detailed functional profiles obtained in this patient and review the cases of four previously described patients in whom dissociated language functions were found.

scholarly journals Brain Functional Magnetic Resonance Imaging Highlights Altered Connections and Functional Networks in Patients With Hypertension

Hypertension ◽  
2020 ◽  
Vol 76 (5) ◽  
pp. 1480-1490 ◽  
Author(s):  
Lorenzo Carnevale ◽  
Angelo Maffei ◽  
Alessandro Landolfi ◽  
Giovanni Grillea ◽  
Daniela Carnevale ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Resting State ◽  
Diffusion Tensor ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Attention Network ◽  
Dorsal Attention Network ◽  
The Brain

Hypertension is one of the main risk factors for vascular dementia and Alzheimer disease. To predict the onset of these diseases, it is necessary to develop tools to detect the early effects of vascular risk factors on the brain. Resting-state functional magnetic resonance imaging can investigate how the brain modulates its resting activity and analyze how hypertension impacts cerebral function. Here, we used resting-state functional magnetic resonance imaging to explore brain functional-hemodynamic coupling across different regions and their connectivity in patients with hypertension, as compared to subjects with normotension. In addition, we leveraged multimodal imaging to identify the signature of hypertension injury on the brain. Our study included 37 subjects (18 normotensives and 19 hypertensives), characterized by microstructural integrity by diffusion tensor imaging and cognitive profile, who were subjected to resting-state functional magnetic resonance imaging analysis. We mapped brain functional connectivity networks and evaluated the connectivity differences among regions, identifying the altered connections in patients with hypertension compared with subjects with normotension in the (1) dorsal attention network and sensorimotor network; (2) dorsal attention network and visual network; (3) dorsal attention network and frontoparietal network. Then we tested how diffusion tensor imaging fractional anisotropy of superior longitudinal fasciculus correlates with the connections between dorsal attention network and default mode network and Montreal Cognitive Assessment scores with a widespread network of functional connections. Finally, based on our correlation analysis, we applied a feature selection to highlight those most relevant to describing brain injury in patients with hypertension. Our multimodal imaging data showed that hypertensive brains present a network of functional connectivity alterations that correlate with cognitive dysfunction and microstructural integrity. Registration— URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02310217.

Functional Magnetic Resonance Imaging of Language Function in Children

2002 ◽  
Vol 3 (2) ◽  
pp. 132-139 ◽  
Author(s):  
Dianne P. Anderson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Case Studies ◽  
Clinical Samples ◽  
Language Function ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Normal Children ◽  
Language Functions

AbstractFunctional magnetic resonance imaging (fMRI) has been recognised as a neuroimaging technique suitable for examination of higher cognitive function in children. It has been used to elucidate cognitive neural networks associated with various aspects of language function in several group and case studies of school-aged children. Language function has been lateralised and localised with fMRI in clinical samples, neurologically normal children and children with developmental language disorders. Issues of plasticity of language function during development and following injury have also been considered. Several paediatric case studies have also raised questions with respect to the interpretation of fMRI language activation. In spite of methodological challenges, fMRI has proved a useful technique for examination of the brain-behaviour relationship in developmental language functions. This paper reviews fMRI studies of language, including reading, in children.

Discordance between functional magnetic resonance imaging during silent speech tasks and intraoperative speech arrest

2005 ◽  
Vol 103 (2) ◽  
pp. 267-274 ◽  
Author(s):  
Nicole Petrovich ◽  
Andrei I. Holodny ◽  
Viviane Tabar ◽  
Denise D. Correa ◽  
Joy Hirsch ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Inferior Frontal Gyrus ◽  
Hemispheric Dominance ◽  
Cortical Mapping ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Neurosurgical Planning ◽  
Silent Speech ◽  
Fine Print

Object. The goal of this study was to investigate discordance between the location of speech arrest during awake cortical mapping, a common intraoperative indicator of hemispheric dominance, and silent speech functional magnetic resonance (fMR) imaging maps of frontal language function. Methods. Twenty-one cases were reviewed retrospectively. Images of silent speech fMR imaging activation were coregistered to anatomical MR images obtained for neuronavigation. These were compared with the intraoperative cortical photographs and the behavioral results of electrocorticography during awake craniotomy. An fMR imaging control study of three healthy volunteers was then conducted to characterize the differences between silent and vocalized speech fMR imaging protocols used for neurosurgical planning. Conclusions. Results of fMR imaging showed consistent and predominant activation of the inferior frontal gyrus (IFG) during silent speech tasks. During intraoperative mapping, however, 16 patients arrested in the precentral gyrus (PRG), well posterior to the fMR imaging activity. Of those 16, 14 arrested only in the PRG and not in the IFG as silent speech fMR imaging predicted. The control fMR imaging study showed that vocalized speech fMR imaging shifts the location of the fMR imaging prediction to include the motor strip and may be more appropriate for neurosurgical planning.

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