scholarly journals Language hemispheric dominance analyzed with magnetic resonance DTI: correlation with the Wada test

2020 ◽  
pp. 1-8
Author(s):  
Juan Delgado-Fernández ◽  
Maria Ángeles García-Pallero ◽  
Rafael Manzanares-Soler ◽  
Pilar Martín-Plasencia ◽  
Guillermo Blasco ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Diffusion Tensor ◽  
Hemispheric Dominance ◽  
Uncinate Fasciculus ◽  
Arcuate Fasciculus ◽  
Dominant Hemisphere ◽  
Wada Test ◽  
Pharmacoresistant Epilepsy ◽  
Linear Discriminant ◽  
Dominance Testing

OBJECTIVELanguage lateralization is a major concern in some patients with pharmacoresistant epilepsy who will face surgery; in these patients, hemispheric dominance testing is essential to avoid further complications. The Wada test is considered the gold standard examination for language localization, but is invasive and requires many human and material resources. Functional MRI and tractography with diffusion tensor imaging (DTI) have demonstrated that they could be useful for locating language in epilepsy surgery, but there is no evidence of the correlation between the Wada test and DTI MRI in language dominance.METHODSThe authors performed a retrospective review of patients who underwent a Wada test before epilepsy surgery at their institution from 2012 to 2017. The authors retrospectively analyzed fractional anisotropy (FA), number and length of fibers, and volume of the arcuate fasciculus and uncinate fasciculus, comparing dominant and nondominant hemispheres.RESULTSTen patients with temporal lobe epilepsy were reviewed. Statistical analysis showed that the mean FA of the arcuate fasciculus in the dominant hemisphere was higher than in the nondominant hemisphere (0.369 vs 0.329, p = 0.049). Also, the number of fibers in the arcuate fasciculus was greater in the dominant hemisphere (881.5 vs 305.4, p = 0.003). However, no differences were found in the FA of the uncinate fasciculus or number of fibers between hemispheres. The length of fibers of the uncinate fasciculus was longer in the dominant side (74.4 vs 50.1 mm, p = 0.05). Volume in both bundles was more prominent in the dominant hemisphere (12.12 vs 6.48 cm3, p = 0.004, in the arcuate fasciculus, and 8.41 vs 4.16 cm3, p = 0.018, in the uncinate fasciculus). Finally, these parameters were compared in patients in whom the seizure focus was situated in the dominant hemisphere: FA (0.37 vs 0.30, p = 0.05), number of fibers (114.4 vs 315.6, p = 0.014), and volume (12.58 vs 5.88 cm3, p = 0.035) in the arcuate fasciculus were found to be statistically significantly higher in the dominant hemispheres. Linear discriminant analysis of FA, number of fibers, and volume of the arcuate fasciculus showed a correct discrimination in 80% of patients (p = 0.024).CONCLUSIONSThe analysis of the arcuate fasciculus and other tract bundles by DTI could be a useful tool for language location testing in the preoperative study of patients with refractory epilepsy.

scholarly journals Structural disconnectivity in schizophrenia: a diffusion tensor magnetic resonance imaging study

2003 ◽  
Vol 182 (5) ◽  
pp. 439-443 ◽  
Author(s):  
J. Burns ◽  
D. Job ◽  
M. E. Bastin ◽  
H. Whalley ◽  
T. Macgillivray ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
Uncinate Fasciculus ◽  
Arcuate Fasciculus ◽  
Resonance Imaging ◽  
White Matter Tracts

BackgroundThere is growing evidence that schizophrenia is a disorder of cortical connectivity Specifically, frontotemporal and frontoparietal connections are thought to be functionally impaired. Diffusion tensor magnetic resonance imaging (DT–MRI) is a technique that has the potential to demonstrate structural disconnectivity in schizophrenia.AimsTo investigate the structural integrity of frontotemporal and frontoparietal white matter tracts in schizophrenia.MethodThirty patients with DSM–IV schizophrenia and thirty matched control subjects underwent DT–MRI and structural MRI. Fractional anisotropy – an index of the integrity of white matter tracts – was determined in the uncinate fasciculus, the anterior cingulum and the arcuate fasciculus and analysed using voxel-based morphometry.ResultsThere was reduced fractional anisotropy in the left uncinate fasciculus and left arcuate fasciculus in patients with schizophrenia compared with controls.ConclusionsThe findings of reduced white matter tract integrity in the left uncinate fasciculus and left arcuate fasciculus suggest that there is frontotemporal and frontoparietal structural disconnectivity in schizophrenia.

scholarly journals Regions of white matter abnormalities in the arcuate fasciculus in veterans with anger and aggression problems

2019 ◽  
Vol 225 (4) ◽  
pp. 1401-1411 ◽  
Author(s):  
Szabolcs David ◽  
Lieke Heesink ◽  
Elbert Geuze ◽  
Thomas Gladwin ◽  
Jack van Honk ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Military Veterans ◽  
Self Regulation ◽  
Brain Regions ◽  
Microstructural Properties ◽  
Uncinate Fasciculus ◽  
Arcuate Fasciculus ◽  
White Matter Connectivity ◽  
Diffusion Tensor Imaging Tractography

AbstractAggression after military deployment is a common occurrence in veterans. Neurobiological research has shown that aggression is associated with a dysfunction in a network connecting brain regions implicated in threat processing and emotion regulation. However, aggression may also be related to deficits in networks underlying communication and social cognition. The uncinate and arcuate fasciculi are integral to these networks, thus studying potential abnormalities in these white matter connections can further our understanding of anger and aggression problems in military veterans. Here, we use diffusion tensor imaging tractography to investigate white matter microstructural properties of the uncinate fasciculus and the arcuate fasciculus in veterans with and without anger and aggression problems. A control tract, the parahippocampal cingulum was also included in the analyses. More specifically, fractional anisotropy (FA) estimates are derived along the trajectory from all fiber pathways and compared between both groups. No between-group FA differences are observed for the uncinate fasciculus and the cingulum, however parts of the arcuate fasciculus show a significantly lower FA in the group of veterans with aggression and anger problems. Our data suggest that abnormalities in arcuate fasciculus white matter connectivity that are related to self-regulation may play an important role in the etiology of anger and aggression in military veterans.

scholarly journals Asymmetric transcallosal conduction delay leads to finer bimanual coordination

2020 ◽  
Author(s):  
Marta Bortoletto ◽  
Laura Bonzano ◽  
Agnese Zazio ◽  
Clarissa Ferrari ◽  
Ludovico Pedullà ◽  
...  
Keyword(s):  
Information Transfer ◽  
Bimanual Coordination ◽  
Diffusion Tensor ◽  
Silent Period ◽  
Hemispheric Dominance ◽  
Conduction Delay ◽  
Dominant Hemisphere ◽  
Interhemispheric Communication ◽  
Temporal Features ◽  
Motor Areas

AbstractIt has been theorized that hemispheric dominance and a more segregated information processing have evolved to overcome long conduction delay through the corpus callosum (TCD) but that this may still impact behavioral performance mostly in tasks requiring high timing accuracy. Nevertheless, a thorough understanding of the temporal features of interhemispheric communication is missing due to methodological shortcomings. Here, we show in the motor system that TCD can be measured from transcranial magnetic stimulation (TMS) -evoked potentials (TEPs): by integrating TEPs with diffusion tensor imaging (DTI) and peripheral measures of interhemispheric inhibition (i.e., the ipsilateral silent period-iSP), we show that P15 TEP component reflects TCD between motor areas. Importantly, we report that better bimanual coordination is achieved when TCD between motor areas is asymmetric. These results suggest that interhemispheric communication can be optimized through asymmetric connectivity, in which information transfer is faster from the dominant hemisphere to the non-dominant hemisphere.

scholarly journals Perspectives on (A)symmetry of Arcuate Fasciculus. A Short Review About Anatomy, Tractography and TMS for Arcuate Fasciculus Reconstruction in Planning Surgery for Gliomas in Language Areas

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrea Di Cristofori ◽  
Gianpaolo Basso ◽  
Camilla de Laurentis ◽  
Ilaria Mauri ◽  
Martina Andrea Sirtori ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Preoperative Evaluation ◽  
Brain Magnetic Resonance Imaging ◽  
Connectionist Model ◽  
Arcuate Fasciculus ◽  
Human Beings ◽  
Dominant Hemisphere ◽  
Language Functions ◽  
Dti Tractography ◽  
Language Areas

Gliomas are brain tumors that are treated with surgical resection. Prognosis is influenced by the extent of resection and postoperative neurological status. As consequence, given the extreme interindividual and interhemispheric variability of subcortical white matter (WM) surgical planning requires to be patient's tailored. According to the “connectionist model,” there is a huge variability among both cortical areas and subcortical WM in all human beings, and it is known that brain is able to reorganize itself and to adapt to WM lesions. Brain magnetic resonance imaging diffusion tensor imaging (DTI) tractography allows visualization of WM bundles. Nowadays DTI tractography is widely available in the clinical setting for presurgical planning. Arcuate fasciculus (AF) is a long WM bundle that connects the Broca's and Wernicke's regions with a complex anatomical architecture and important role in language functions. Thus, its preservation is important for the postoperative outcome, and DTI tractography is usually performed for planning surgery within the language-dominant hemisphere. High variability among individuals and an asymmetrical pattern has been reported for this WM bundle. However, the functional relevance of AF in the contralateral non-dominant hemisphere in case of tumoral or surgical lesion of the language-dominant AF is unclear. This review focuses on AF anatomy with special attention to its asymmetry in both normal and pathological conditions and how it may be explored with preoperative tools for planning surgery on gliomas in language areas. Based on the findings available in literature, we finally speculate about the potential role of preoperative evaluation of the WM contralateral to the surgical site.

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.

scholarly journals Delayed development of aphasia related to degeneration of the arcuate fasciculus in the dominant hemisphere nine years after the onset in a patient with intracerebral hemorrhage: a case report

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Min Jye Cho ◽  
Sung Ho Jang
Keyword(s):  
Intracerebral Hemorrhage ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Magnetic Resonance Images ◽  
Arcuate Fasciculus ◽  
Dominant Hemisphere ◽  
Neural Degeneration ◽  
Delayed Development ◽  
Hemosiderin Deposits ◽  
Post Onset

Abstract Background We report on a patient with an intracerebral hemorrhage (ICH), who showed delayed development of aphasia, which was demonstrated via follow up diffusion tensor tractography (DTT) to be related to neural degeneration of the arcuate fasciculus (AF). Case presentation A 51-year-old, right-handed male presented with right hemiparesis, which occurred at the onset of a spontaneous ICH in the left corona radiata and basal ganglia. Brain magnetic resonance images showed a hematoma in the left subcortical area at one month after onset and hemosiderin deposits in the left subcortical area at nine years after onset. At four weeks after onset, he exhibited severe aphasia, and Western Aphasia Battery (WAB) testing revealed an aphasia quotient in the 39.6 percentile (%ile). However, his aphasia improved to nearly a normal state, and at three months after onset, his aphasia quotient was in the 90.5 %ile. At approximately eight years after onset, he began to show aphasia, and his aphasia increased slowly with time resulting in a WAB aphasia quotient in the 12.5 %ile at nine years after onset. The integrity of the left AF over the hematoma was preserved on 1-month post-onset DTT. However, the middle portion of the left AF in the middle of the hemosiderin deposits showed discontinuation on 9-year post-onset DTT. The fractional anisotropy value of the left AF was higher on the 9-year post-onset DTT (0.48) than that on the 1-month post-onset DTT (0.35), whereas the mean diffusivity value was lower on the 9-year post-onset DTT (0.10) than that on the 1-month post-onset DTT (0.32). The fiber number of the left AF was decreased to 175 on the 9-year post-onset DTT from 239 on the 1-month post-onset DTT. Conclusions We report on a patient with ICH who showed delayed development of aphasia, which appeared to be related to degeneration of the AF in the dominant hemisphere. Our results suggest that DTT would be useful in ruling out neural degeneration of the AF.

scholarly journals Tractography-Based Analysis of Morphological and Anatomical Characteristics of the Uncinate Fasciculus in Human Brains

2020 ◽  
Vol 10 (10) ◽  
pp. 709 ◽  
Author(s):  
Sara Kierońska ◽  
Paweł Sokal ◽  
Marta Dura ◽  
Magdalena Jabłońska ◽  
Marcin Rudaś ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Morphological Characteristics ◽  
Psychological State ◽  
Hemispheric Dominance ◽  
Uncinate Fasciculus ◽  
Volume Number ◽  
The Right

(1) Background: The uncinate fasciculus (UF) is a white matter bundle connecting the prefrontal cortex and temporal lobe. The functional role of the uncinate fasciculus is still uncertain. The role of the UF is attributed to the emotional empathy network. The present study aimed to more accurately the describe anatomical variability of the UF by focusing on the volume of fibers and testing for correlations with sex and age. (2) Material and Methods: Magnetic resonance imaging of adult patients with diffusion tensor imaging (DTI) was performed on 34 patients. The total number of fibers, volume of UF, and number of tracts were processed using DSI studio software. The DSI studio allows for mapping of different nerve pathways and visualizing of the obtained results using spatial graphics. (3) Results: The total number of UF tracts was significantly higher in the right hemisphere compared to the left hemisphere (right M ± SD = 52 ± 24; left: 39 ± 25, p < 0.05). A hook-shaped UF was the most common variant (91.7%). The UF volumes were larger in men (1410 ± 150.7 mm3) as compared to women (1325 ± 133.2 mm3) (p < 0.05). The mean fractional anisotropy (FA) values of the UF were significantly larger on the left side 0.597, while the right UF had an average of 0.346 (p < 0.05). Patients older than 50 years old had a significantly higher value of mean diffusivity (MD) (p = 0.034). In 73.5% of patients, a greater number of fibers terminated in the inferior part of the inferior frontal gyrus. (4) Conclusions: The morphological characteristics of the UF, unlike the shape, are associated with sex and are characterized by hemispheric dominance. These findings confirm the results of the previous studies. Future research should examine the potential correlation among the UF volume, number of fibers, and total brain volume in both sexes and patient psychological state.

scholarly journals A Sensitive Diffusion Tensor Imaging Quantification Method to Detect Language Laterality in Children

2011 ◽  
Vol 26 (12) ◽  
pp. 1516-1521 ◽  
Author(s):  
Vijay Narayan Tiwari ◽  
Jeong-Won Jeong ◽  
Eishi Asano ◽  
Robert Rothermel ◽  
Csaba Juhasz ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Fractional Anisotropy ◽  
Diffusion Tensor ◽  
Orientation Distribution ◽  
Volumetric Analysis ◽  
Arcuate Fasciculus ◽  
Wada Test ◽  
Laterality Index ◽  
Fiber Orientation Distribution ◽  
Language Laterality

Using diffusion tensor imaging tractography and color-coded anisotropy map quantification, we investigated asymmetry of the arcuate fasciculus to determine language laterality in children and compared it with the Wada test. Arcuate fasciculus volume and fractional anisotropy were measured after tractography. We also quantified the fiber orientation distribution in the arcuate fasciculus region, ie, the fraction of arcuate fasciculus fibers oriented in the anteroposterior and mediolateral directions. A Laterality Index was calculated for each of the measured parameters. Volumetric analysis of the arcuate fasciculus showed asymmetry favoring the language dominant hemisphere ( P = .02), while fractional anisotropy showed no significant asymmetry ( P = .07). The mean anteroposterior and mediolateral components on the language dominant side were significantly higher than on the nondominant side ( P = .003 and .002, respectively). The Laterality Index values were concordant with the Wada test results except for 1 case. Fractional anisotropy also falsely lateralized language in 1 case.

scholarly journals Structural and Functional Imaging in Glioma Management

Neurosurgery ◽  
2020 ◽  
Author(s):  
Bledi C Brahimaj ◽  
Ryan B Kochanski ◽  
John J Pearce ◽  
Melike Guryildirim ◽  
Carter S Gerard ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Imaging Modalities ◽  
Hemispheric Dominance ◽  
Tumor Control ◽  
Histopathological Diagnosis ◽  
Glioma Surgery ◽  
Multiple Modalities ◽  
Advantages And Disadvantages ◽  
Multiple Imaging

Abstract The goal of glioma surgery is maximal safe resection in order to provide optimal tumor control and survival benefit to the patient. There are multiple imaging modalities beyond traditional contrast-enhanced magnetic resonance imaging (MRI) that have been incorporated into the preoperative workup of patients presenting with gliomas. The aim of these imaging modalities is to identify cortical and subcortical areas of eloquence, and their relationship to the lesion. In this article, multiple modalities are described with an emphasis on the underlying technology, clinical utilization, advantages, and disadvantages of each. functional MRI and its role in identifying hemispheric dominance and areas of language and motor are discussed. The nuances of magnetoencephalography and transcranial magnetic stimulation in localization of eloquent cortex are examined, as well as the role of diffusion tensor imaging in defining normal white matter tracts in glioma surgery. Lastly, we highlight the role of stimulated Raman spectroscopy in intraoperative histopathological diagnosis of tissue to guide tumor resection. Tumors may shift the normal arrangement of functional anatomy in the brain; thus, utilization of multiple modalities may be helpful in operative planning and patient counseling for successful surgery.

Sign in / Sign up

Export Citation Format

Share Document