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Agarwal S, Sair HI, Gujar S, Pillai JJ. Language Mapping With fMRI: Current Standards and Reproducibility. Top Magn Reson Imaging 2019; 28:225-233. [PMID: 31385902 DOI: 10.1097/rmr.0000000000000216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Clinical use of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a relatively new phenomenon, with only about 3 decades of collective experience. Nevertheless, task-based BOLD fMRI has been widely accepted for presurgical planning, over traditional methods, which are invasive and at times perilous. Many studies have demonstrated the ability of BOLD fMRI to make substantial clinical impact with respect to surgical planning and preoperative risk assessment, especially to localize the eloquent motor and visual areas. Reproducibility and repeatability of language fMRI are important in the assessment of its clinical usefulness. There are national efforts currently underway to standardize language fMRI. The American Society of Functional Neuroradiology (ASFNR) has recently provided guidelines on fMRI paradigm algorithms for presurgical language assessment for language lateralization and localization. In this review article, we provide a comprehensive overview of current standards of language fMRI mapping and its reproducibility.
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Affiliation(s)
- Shruti Agarwal
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Haris I Sair
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Sachin Gujar
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jay J Pillai
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD
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EEG spatiospectral patterns and their link to fMRI BOLD signal via variable hemodynamic response functions. J Neurosci Methods 2019; 318:34-46. [PMID: 30802472 DOI: 10.1016/j.jneumeth.2019.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/29/2018] [Accepted: 02/17/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Spatial and temporal resolution of brain network activity can be improved by combining different modalities. Functional Magnetic Resonance Imaging (fMRI) provides full brain coverage with limited temporal resolution, while electroencephalography (EEG), estimates cortical activity with high temporal resolution. Combining them may provide improved network characterization. NEW METHOD We examined relationships between EEG spatiospectral pattern timecourses and concurrent fMRI BOLD signals using canonical hemodynamic response function (HRF) with its 1st and 2nd temporal derivatives in voxel-wise general linear models (GLM). HRF shapes were derived from EEG-fMRI time courses during "resting-state", visual oddball and semantic decision paradigms. RESULTS The resulting GLM F-maps self-organized into several different large-scale brain networks (LSBNs) often with different timing between EEG and fMRI revealed through differences in GLM-derived HRF shapes (e.g., with a lower time to peak than the canonical HRF). We demonstrate that some EEG spatiospectral patterns (related to concurrent fMRI) are weakly task-modulated. COMPARISON WITH EXISTING METHOD(S) Previously, we demonstrated 14 independent EEG spatiospectral patterns within this EEG dataset, stable across the resting-state, visual oddball and semantic decision paradigms. Here, we demonstrate that their time courses are significantly correlated with fMRI dynamics organized into LSBN structures. EEG-fMRI derived HRF peak appears earlier than the canonical HRF peak, which suggests limitations when assuming a canonical HRF shape in EEG-fMRI. CONCLUSIONS This is the first study examining EEG-fMRI relationships among independent EEG spatiospectral patterns over different paradigms. The findings highlight the importance of considering different HRF shapes when spatiotemporally characterizing brain networks using EEG and fMRI.
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Agarwal S, Hua J, Sair HI, Gujar S, Bettegowda C, Lu H, Pillai JJ. Repeatability of language fMRI lateralization and localization metrics in brain tumor patients. Hum Brain Mapp 2018; 39:4733-4742. [PMID: 30076768 PMCID: PMC6218318 DOI: 10.1002/hbm.24318] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/29/2018] [Accepted: 07/05/2018] [Indexed: 11/12/2022] Open
Abstract
To assess the within-subject intra-scan session repeatability of language functional MRI (fMRI) activation maps in patients with brain tumors who were undergoing presurgical fMRI as part of their preoperative clinical workup. Sentence completion (SC) and silent word generation (SWG) tasks were used for language localization and hemispheric lateralization for identifying the primary language cortex. Within-subject repeatability for each of these paradigms was assessed in right-handed patients-37 for SC and 78 for SWG. Repeatability of activation maps between consecutive runs of the same task within the same scan session was evaluated by comparing lateralization indexes in holohemispheric and regional language areas. Displacement of center of activation between consecutive runs was also used to assess the repeatability of activation maps. Holohemispheric and regional language lateralization results demonstrated high intra-subject intra-scan repeatability when lateralization indices were calculated using threshold-dependent and threshold-independent approaches. The high repeatability is demonstrated both when centers of mass of activation are considered within key eloquent regions of the brain, such as Broca's area and Wernicke's area, as well as in larger more inclusive expressive and receptive language regions. We examined two well-known and widely accepted language tasks that are known to activate eloquent language cortex. We have demonstrated very high degree of repeatability at a single-subject level within single scan sessions of language mapping in a large cohort of brain tumor patients undergoing presurgical fMRI across several years at our institution.
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Affiliation(s)
- Shruti Agarwal
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
| | - Jun Hua
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
- F. M. Kirby Research Center For Functional Brain ImagingKennedy Krieger InstituteBaltimoreMaryland
| | - Haris I. Sair
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
| | - Sachin Gujar
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
| | - Chetan Bettegowda
- Department of NeurosurgeryJohns Hopkins University School of MedicineBaltimoreMaryland
| | - Hanzhang Lu
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
- F. M. Kirby Research Center For Functional Brain ImagingKennedy Krieger InstituteBaltimoreMaryland
| | - Jay J. Pillai
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMaryland
- Department of NeurosurgeryJohns Hopkins University School of MedicineBaltimoreMaryland
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Trimmel K, van Graan AL, Caciagli L, Haag A, Koepp MJ, Thompson PJ, Duncan JS. Left temporal lobe language network connectivity in temporal lobe epilepsy. Brain 2018; 141:2406-2418. [DOI: 10.1093/brain/awy164] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 04/24/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Karin Trimmel
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- Department of Neurology, Medical University of Vienna, 1090-Vienna, Austria
| | - Andre L van Graan
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Lorenzo Caciagli
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Anja Haag
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Matthias J Koepp
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Pamela J Thompson
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - John S Duncan
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0LR, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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Gonzálvez GG, Trimmel K, Haag A, van Graan LA, Koepp MJ, Thompson PJ, Duncan JS. Activations in temporal areas using visual and auditory naming stimuli: A language fMRI study in temporal lobe epilepsy. Epilepsy Res 2016; 128:102-112. [PMID: 27833066 DOI: 10.1016/j.eplepsyres.2016.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/05/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Verbal fluency functional MRI (fMRI) is used for predicting language deficits after anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), but primarily engages frontal lobe areas. In this observational study we investigated fMRI paradigms using visual and auditory stimuli, which predominately involve language areas resected during ATLR. METHODS Twenty-three controls and 33 patients (20 left (LTLE), 13 right (RTLE)) were assessed using three fMRI paradigms: verbal fluency, auditory naming with a contrast of auditory reversed speech; picture naming with a contrast of scrambled pictures and blurred faces. RESULTS Group analysis showed bilateral temporal activations for auditory naming and picture naming. Correcting for auditory and visual input (by subtracting activations resulting from auditory reversed speech and blurred pictures/scrambled faces respectively) resulted in left-lateralised activations for patients and controls, which was more pronounced for LTLE compared to RTLE patients. Individual subject activations at a threshold of T>2.5, extent >10 voxels, showed that verbal fluency activated predominantly the left inferior frontal gyrus (IFG) in 90% of LTLE, 92% of RTLE, and 65% of controls, compared to right IFG activations in only 15% of LTLE and RTLE and 26% of controls. Middle temporal (MTG) or superior temporal gyrus (STG) activations were seen on the left in 30% of LTLE, 23% of RTLE, and 52% of controls, and on the right in 15% of LTLE, 15% of RTLE, and 35% of controls. Auditory naming activated temporal areas more frequently than did verbal fluency (LTLE: 93%/73%; RTLE: 92%/58%; controls: 82%/70% (left/right)). Controlling for auditory input resulted in predominantly left-sided temporal activations. Picture naming resulted in temporal lobe activations less frequently than did auditory naming (LTLE 65%/55%; RTLE 53%/46%; controls 52%/35% (left/right)). Controlling for visual input had left-lateralising effects. CONCLUSION Auditory and picture naming activated temporal lobe structures, which are resected during ATLR, more frequently than did verbal fluency. Controlling for auditory and visual input resulted in more left-lateralised activations. We hypothesise that these paradigms may be more predictive of postoperative language decline than verbal fluency fMRI.
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Affiliation(s)
- Gloria G Gonzálvez
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Karin Trimmel
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom.
| | - Anja Haag
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Louis A van Graan
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Matthias J Koepp
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Pamela J Thompson
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - John S Duncan
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St. Peter, SL9 0LR, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
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Batouli SAH, Hasani N, Gheisari S, Behzad E, Oghabian MA. Evaluation of the factors influencing brain language laterality in presurgical planning. Phys Med 2016; 32:1201-1209. [PMID: 27742256 DOI: 10.1016/j.ejmp.2016.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 06/07/2016] [Accepted: 06/17/2016] [Indexed: 10/20/2022] Open
Abstract
Brain lesions cause functional deficits, and one treatment for this condition is lesion resection. In most cases, presurgical planning (PSP) and the information from laterality indices are necessary for maximum preservation of the critical functions after surgery. Language laterality index (LI) is reliably estimated using functional magnetic resonance imaging (fMRI); however, this measure is under the influence of some external factors. In this study, we investigated the influence of a number of factors on language LI, using data from 120 patients (mean age=35.65 (±13.4) years) who underwent fMRI for PSP. Using two proposed language tasks from our previous works, brain left hemisphere was showed to be dominant for the language function, although a higher LI was obtained using the "Word Generation" task, compared to the "Reverse Word Reading". In addition, decline of LIs with age, and lower LI when the lesion invaded brain language area were observed. Meanwhile, gender, lesion side (affected hemisphere), LI calculation strategy, and fMRI analysis Z-values did not statistically show any influences on the LIs. Although fMRI is widely used to estimate language LI, it is shown here that in order to present a reliable language LI and to correctly select the dominant hemisphere of the brain, the influence of external factors should be carefully considered.
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Affiliation(s)
- Seyed Amir Hossein Batouli
- Neuroimaging and Analysis Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Nafiseh Hasani
- Neuroimaging and Analysis Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Sara Gheisari
- Neuroimaging and Analysis Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Ebrahim Behzad
- School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oghabian
- Neuroimaging and Analysis Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
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Buklina SB, Batalov AI, Fadeeva LM, Smirnov AS, Goryaynov SA, Zhukov VY, Poddubskaya AA, Ogurtsova AA, Kulikov AS, Chumakova AP, Pronin IN, Kornienko VN, Potapov AA. [The structure of activation of the language zone in patients with intracerebral tumors according to fMRI with respect to tumor location and the functional asymmetry profile]. ZHURNAL VOPROSY NEĬROKHIRURGII IMENI N. N. BURDENKO 2016; 79:60-68. [PMID: 26529535 DOI: 10.17116/neiro201579360-68] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
MATERIAL AND METHODS A total of 50 patients were examined prior to surgical resection of intracranial tumors of the temporal and frontal lobes. Left-sided tumors were observed in 33 patients and right-sided tumors were observed in 17 patients. The functional asymmetry profile was determined using self-assessment, the Annet questionnaire, and the dichotic listening task. Twelve patients were left-handers or retrained left-handers and the remaining 38 patients were right-handers. FMRI examination was carried out on a 3.0 T SignaHDxt magnetic resonance tomograph (GE). The standard language block design paradigm was used in the study. We used the following tests: 1) recitation of months in reverse order; 2) generation of nouns according to the initial letters shown on the screen (K, M, L, N, P, C); 3) generation of verbs according to simple actions shown on the screen; 4) producing sentences using nouns shown on the screen; 5) listening to text through headphones. Data were processed using the standard BrainWave PA software (General Electric). Z-test was used in the range from 6 to 9. In all the studies, p<0.001. Statistical data processing included the nonparametric Spearman's test to determine the correlation between lateralization of the detected activation zone under speech load and tumor location (tumor is adjacent to the language zone, invades the language zone, or is located far from the language zone), as well as left- or right-handedness. RESULTS Among 16 patients (right-handers and 2 left-handers) the activation of language zones was observed only on the left side; in one left-handed patient, Broca's area was detected only on the right side. In other patients (including right-handers with right-sided tumors), lateralization of language zones was different, including bilateral. Statistical processing revealed that bilateral activation of both Broca's and Wernicke's areas was more frequently observed in left-handers. Broca's area was more frequently detected on the left side in the presence of a distant tumor, while this trend did not apply for Wernicke's area. CONCLUSION Localization of activation of Broca's area is more dependent on tumor location, while it depends on personal characteristics of an individual in the case of Wernicke's area.
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Affiliation(s)
- S B Buklina
- Burdenko Neurosurgical Institute, Moscow, Russia
| | - A I Batalov
- Burdenko Neurosurgical Institute, Moscow, Russia
| | - L M Fadeeva
- Burdenko Neurosurgical Institute, Moscow, Russia
| | - A S Smirnov
- Burdenko Neurosurgical Institute, Moscow, Russia
| | | | - V Yu Zhukov
- Burdenko Neurosurgical Institute, Moscow, Russia
| | | | | | - A S Kulikov
- Burdenko Neurosurgical Institute, Moscow, Russia
| | | | - I N Pronin
- Burdenko Neurosurgical Institute, Moscow, Russia
| | | | - A A Potapov
- Burdenko Neurosurgical Institute, Moscow, Russia
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Chaudhary UJ, Duncan JS. Applications of blood-oxygen-level-dependent functional magnetic resonance imaging and diffusion tensor imaging in epilepsy. Neuroimaging Clin N Am 2014; 24:671-94. [PMID: 25441507 DOI: 10.1016/j.nic.2014.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The lifetime prevalence of epilepsy ranges from 2.7 to 12.4 per 1000 in Western countries. Around 30% of patients with epilepsy remain refractory to antiepileptic drugs and continue to have seizures. Noninvasive imaging techniques such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have helped to better understand mechanisms of seizure generation and propagation, and to localize epileptic, eloquent, and cognitive networks. In this review, the clinical applications of fMRI and DTI are discussed, for mapping cognitive and epileptic networks and organization of white matter tracts in individuals with epilepsy.
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Affiliation(s)
- Umair J Chaudhary
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK.
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK; Queen Square Division, UCLH NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
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Geißler A, Matt E, Fischmeister F, Wurnig M, Dymerska B, Knosp E, Feucht M, Trattnig S, Auff E, Fitch WT, Robinson S, Beisteiner R. Differential functional benefits of ultra highfield MR systems within the language network. Neuroimage 2014; 103:163-170. [PMID: 25255049 PMCID: PMC4263528 DOI: 10.1016/j.neuroimage.2014.09.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/03/2014] [Accepted: 09/15/2014] [Indexed: 11/16/2022] Open
Abstract
Several investigations have shown limitations of fMRI reliability with the current standard field strengths. Improvement is expected from ultra highfield systems but studies on possible benefits for cognitive networks are lacking. Here we provide an initial investigation on a prominent and clinically highly-relevant cognitive function: language processing in individual brains. 26 patients evaluated for presurgical language localization were investigated with a standardized overt language fMRI paradigm on both 3T and 7T MR scanners. During data acquisition and analysis we made particular efforts to minimize effects not related to static magnetic field strength differences. Six measures relevant for functional activation showed a large dissociation between essential language network nodes: although in Wernicke's area 5/6 measures indicated a benefit of ultra highfield, in Broca's area no comparison was significant. The most important reason for this discrepancy was identified as being an increase in susceptibility-related artifacts in inferior frontal brain areas at ultra high field. We conclude that functional UHF benefits are evident, however these depend crucially on the brain region investigated and the ability to control local artifacts.
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Affiliation(s)
- A Geißler
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria; High Field MR Center, Medical University of Vienna, Austria; Department of Neurology, Medical University of Vienna, Austria
| | - E Matt
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria; High Field MR Center, Medical University of Vienna, Austria; Department of Neurology, Medical University of Vienna, Austria
| | - F Fischmeister
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria; High Field MR Center, Medical University of Vienna, Austria; Department of Neurology, Medical University of Vienna, Austria
| | - M Wurnig
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria; High Field MR Center, Medical University of Vienna, Austria; Department of Neurology, Medical University of Vienna, Austria
| | - B Dymerska
- High Field MR Center, Medical University of Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - E Knosp
- Department of Neurosurgery, Medical University of Vienna, Austria
| | - M Feucht
- Department of Pediatrics, Medical University of Vienna, Austria
| | - S Trattnig
- High Field MR Center, Medical University of Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - E Auff
- Department of Neurology, Medical University of Vienna, Austria
| | - W T Fitch
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
| | - S Robinson
- High Field MR Center, Medical University of Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - R Beisteiner
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria; High Field MR Center, Medical University of Vienna, Austria; Department of Neurology, Medical University of Vienna, Austria.
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10
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Chaudhary U, Hall M, Gonzalez J, Elbaum L, Bloyer M, Godavarty A. Motor response investigation in individuals with cerebral palsy using near infrared spectroscopy: pilot study. APPLIED OPTICS 2014; 53:503-10. [PMID: 24514139 DOI: 10.1364/ao.53.000503] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 12/20/2013] [Indexed: 05/20/2023]
Abstract
Cerebral palsy (CP) describes a group of motor impairment syndromes secondary to genetic that may be due to acquired disorders of the developing brain. In this study, near infrared spectroscopy (NIRS) is used to investigate the prefrontal cortical activation and lateralization in response to the planning and execution of motor skills in controls and individuals with CP. The prefrontal cortex, which plays a dominant role in the planning and execution of motor skill stimulus, is noninvasively imaged using a continuous wave-based NIRS system. During the study, 7 controls (4 right-handed and 3 left-handed) and 2 individuals with CP (1 right-handed and 1 left-handed) over 18 years of age performed 30 s of a ball throwing task followed by 30 s rest in a 5-block paradigm. The optical signal acquired from the NIRS system was processed to elucidate the activation and lateralization in the prefrontal region of controls and individuals with CP. The preliminary result indicated a difference in activation between the task and rest conditions in all the participant types. Bilateral dominance was observed in the prefrontal cortex of controls in response to planning and execution of motor skill tasks, while an ipsilateral dominance was observed in individuals with CP. In conjunction, similar contralateral dominance was observed during rest periods, both in controls and individuals with CP.
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11
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Beisteiner R. Improving clinical fMRI: better paradigms or higher field strength? AJNR Am J Neuroradiol 2013; 34:1972-3. [PMID: 23928135 PMCID: PMC7965422 DOI: 10.3174/ajnr.a3722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- R Beisteiner
- Study Group Clinical fMRIDepartment of NeurologyHigh Field MR CenterMedical University of ViennaVienna, Austria
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12
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Fischmeister FPS, Höllinger I, Klinger N, Geissler A, Wurnig MC, Matt E, Rath J, Robinson SD, Trattnig S, Beisteiner R. The benefits of skull stripping in the normalization of clinical fMRI data. NEUROIMAGE-CLINICAL 2013; 3:369-80. [PMID: 24273720 PMCID: PMC3814956 DOI: 10.1016/j.nicl.2013.09.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/11/2013] [Accepted: 09/23/2013] [Indexed: 11/24/2022]
Abstract
Establishing a reliable correspondence between lesioned brains and a template is challenging using current normalization techniques. The optimum procedure has not been conclusively established, and a critical dichotomy is whether to use input data sets which contain skull signal, or whether skull signal should be removed. Here we provide a first investigation into whether clinical fMRI benefits from skull stripping, based on data from a presurgical language localization task. Brain activation changes related to deskulled/not-deskulled input data are determined in the context of very recently developed (New Segment, Unified Segmentation) and standard normalization approaches. Analysis of structural and functional data demonstrates that skull stripping improves language localization in MNI space — particularly when used in combination with the New Segment normalization technique. First investigation of the possible effects of skull-stripping with clinical fMRI data. Comparison of standard and most recent normalization approaches. Skull stripping improves language localization in MNI space.
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Affiliation(s)
- F Ph S Fischmeister
- Study Group Clinical fMRI, Department of Neurology, Medical University of Vienna, Austria ; High Field MR Center, Medical University of Vienna, Austria
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Robinson SD, Schöpf V, Cardoso P, Geissler A, Fischmeister FPS, Wurnig M, Trattnig S, Beisteiner R. Applying independent component analysis to clinical FMRI at 7 t. Front Hum Neurosci 2013; 7:496. [PMID: 24032007 PMCID: PMC3759034 DOI: 10.3389/fnhum.2013.00496] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 08/05/2013] [Indexed: 11/24/2022] Open
Abstract
Increased BOLD sensitivity at 7 T offers the possibility to increase the reliability of fMRI, but ultra-high field is also associated with an increase in artifacts related to head motion, Nyquist ghosting, and parallel imaging reconstruction errors. In this study, the ability of independent component analysis (ICA) to separate activation from these artifacts was assessed in a 7 T study of neurological patients performing chin and hand motor tasks. ICA was able to isolate primary motor activation with negligible contamination by motion effects. The results of General Linear Model (GLM) analysis of these data were, in contrast, heavily contaminated by motion. Secondary motor areas, basal ganglia, and thalamus involvement were apparent in ICA results, but there was low capability to isolate activation in the same brain regions in the GLM analysis, indicating that ICA was more sensitive as well as more specific. A method was developed to simplify the assessment of the large number of independent components. Task-related activation components could be automatically identified via these intuitive and effective features. These findings demonstrate that ICA is a practical and sensitive analysis approach in high field fMRI studies, particularly where motion is evoked. Promising applications of ICA in clinical fMRI include presurgical planning and the study of pathologies affecting subcortical brain areas.
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Affiliation(s)
- Simon Daniel Robinson
- High Field Magnetic Resonance Imaging Centre of Excellence, Medical University of Vienna , Vienna , Austria ; Department of Radiology, Medical University of Vienna , Vienna , Austria
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Belyaev AS, Peck KK, Brennan NMP, Holodny AI. Clinical applications of functional MR imaging. Magn Reson Imaging Clin N Am 2013; 21:269-78. [PMID: 23642553 DOI: 10.1016/j.mric.2012.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Functional magnetic resonance (fMR) imaging for neurosurgical planning has become the standard of care in centers where it is available. Although paradigms to measure eloquent cortices are not yet standardized, simple tasks elicit reliable maps for planning neurosurgical procedures. A patient-specific paradigm design will refine the usability of fMR imaging for prognostication and recovery of function. Certain pathologic conditions and technical issues limit the interpretation of fMR imaging maps in clinical use and should be considered carefully. However, fMR imaging for neurosurgical planning continues to provide insights into how the brain works and how it responds to pathologic insults.
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Affiliation(s)
- Artem S Belyaev
- Functional MRI Laboratory, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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15
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Abstract
Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique that has grown rapidly in popularity over the past decade. It is already prevalent in psychology, cognitive and basic neuroscience research and is being used increasingly as a tool for clinical decision-making in epilepsy. It has been used to determine language location and laterality in patients, sometimes eliminating the need for invasive tests. fMRI can been used pre-surgically to guide resection margins, preserving eloquent cortex. Other fMRI paradigms assessing memory, visual and somatosensory systems have limited clinical applications currently, but show great promise. Simultaneous recording of electroencephalogram (EEG) and fMRI has also provided insights into the networks underlying seizure generation and is increasingly being used in epilepsy centres. In this review, we present some of the current clinical applications for fMRI in the pre-surgical assessment of epilepsy patients, and examine a number of new techniques that may soon become clinically relevant.
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Partovi S, Jacobi B, Rapps N, Zipp L, Karimi S, Rengier F, Lyo JK, Stippich C. Clinical standardized fMRI reveals altered language lateralization in patients with brain tumor. AJNR Am J Neuroradiol 2012; 33:2151-7. [PMID: 22595902 DOI: 10.3174/ajnr.a3137] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Brain tumors affecting language-relevant areas may influence language lateralization. The purpose of this study was to systematically investigate language lateralization in brain tumor patients using clinical language fMRI, comparing the results with a group of healthy volunteers. MATERIALS AND METHODS Fifty-seven strictly right-handed patients with left-hemispheric-space intracranial masses (mainly neoplastic) affecting either the Broca area (n = 19) or Wernicke area (n = 38) were prospectively enrolled in this study. Fourteen healthy volunteers served as a control group. Standardized clinical language fMRI, using visually triggered sentence- and word-generation paradigms, was performed on a 1.5T MR scanner. Semiautomated analyses of all functional data were conducted on an individual basis using BrainVoyager. A regional lateralization index was calculated for Broca and Wernicke areas separately versus their corresponding right-hemisphere homologs. RESULTS In masses affecting the Broca area, a significant decrease in the lateralization index was found when performing word generation (P = .0017), whereas when applying sentence generation, the decrease did not reach statistical significance (P = .851). Masses affecting the Wernicke area induced a significant decrease of the lateralization index when performing sentence generation (P = .0007), whereas when applying word generation, the decrease was not statistically significant (P = .310). CONCLUSIONS Clinical language fMRI was feasible for patients with brain tumors and provided relevant presurgical information by localizing essential language areas and determining language dominance. A significant effect of the brain masses on language lateralization was observed, with a shift toward the contralesional, nondominant hemisphere. This may reflect compensatory mechanisms of the brain to maintain communicative abilities.
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Affiliation(s)
- S Partovi
- Department of Neuroradiology, University Hospital of Basel, Basel, Switzerland.
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17
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Effects of covert and overt paradigms in clinical language fMRI. Acad Radiol 2012; 19:518-25. [PMID: 22281389 DOI: 10.1016/j.acra.2011.12.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 12/24/2011] [Accepted: 12/29/2011] [Indexed: 11/21/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to assess the intrasubject and intersubject reproducibility of functional magnetic resonance imaging (fMRI) language paradigms on language localization and lateralization. MATERIALS AND METHODS Fourteen healthy volunteers were enrolled prospectively and underwent language fMRI using visually triggered covert and overt sentence generation (SG) and word generation (WG) paradigms. Semiautomated analysis of all functional data was performed using Brain Voyager on an individual basis. Regions of interest for Broca's area, Wernicke's area, and their contralateral homologues were drawn. The Euclidean coordinates of the center of gravidity (x, y, and z) of the respective blood oxygenation level-dependent (BOLD) activation cluster, and the correlation of the measured hemodynamic response to the applied reference function (r), relative BOLD signal change as BOLD signal characteristics were measured in each region of interest. Regional lateralization indexes were calculated for Broca's area, Wernicke's area, and their contralateral homologues separately. Wilcoxon's signed-rank test was applied for statistical comparisons (P values < .05 were considered significant). Ten of the 14 volunteers had three repeated measurements to test intrasession reproducibility and intersession reproducibility. RESULTS Overall activation rates for the four paradigms were 89% for covert SG, 82% for overt SG, 89% for covert WG, and 100% for overt WG. When comparing covert and overt paradigms, language localization was significantly different in 17% (Euclidean coordinates) and 19% (BOLD signal characteristics), respectively. Language lateralization was significantly different in 75%. Intrasubject and intersubject reproducibility was excellent, with 3.3% significant differences among all five parameters for language localization and 0% significant differences for language lateralization using covert paradigms. CONCLUSIONS Covert language paradigms (SG and WG) provided highly robust and reproducible localization and lateralization of essential language centers for scans performed on the same and different days. Their overt counterparts achieved confirmatory localization but lower lateralization capabilities. Reference data for presurgical application are provided.
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Smits M, Visch-Brink EG, van de Sandt-Koenderman ME, van der Lugt A. Advanced Magnetic Resonance Neuroimaging of Language Function Recovery After Aphasic Stroke: A Technical Review. Arch Phys Med Rehabil 2012; 93:S4-14. [DOI: 10.1016/j.apmr.2011.02.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 02/18/2011] [Accepted: 02/22/2011] [Indexed: 10/14/2022]
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Preoperative assessment of language areas in epileptic patients using functional MR imaging. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2011. [DOI: 10.1016/j.ejrnm.2011.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Auer T, Schweizer R, Frahm J. An iterative two-threshold analysis for single-subject functional MRI of the human brain. Eur Radiol 2011; 21:2369-87. [PMID: 21710268 DOI: 10.1007/s00330-011-2184-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Current thresholding strategies for the analysis of functional MRI (fMRI) datasets may suffer from specific limitations (e.g. with respect to the required smoothness) or lead to reduced performance for a low signal-to-noise ratio (SNR). Although a previously proposed two-threshold (TT) method offers a promising solution to these problems, the use of preset settings limits its performance. This work presents an optimised TT approach that estimates the required parameters in an iterative manner. METHODS The iterative TT (iTT) method is compared with the original TT method, as well as other established voxel-based and cluster-based thresholding approaches and spatial mixture modelling (SMM) for both simulated data and fMRI of a hometown walking task at different experimental settings (spatial resolution, filtering and SNR). RESULTS In general, the iTT method presents with remarkable sensitivity and good specificity that outperforms all conventional approaches tested except for SMM in a few cases. This also holds true for challenging conditions such as high spatial resolution, the absence of filtering, high noise level, or a low number of task repetitions. CONCLUSION Thus, iTT emerges as a good candidate for both scientific fMRI studies at high spatial resolution and more routine applications for clinical purposes.
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Affiliation(s)
- Tibor Auer
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Am Fassberg 11, 37070 Göttingen, Germany.
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Pelletier I, Paquette N, Lepore F, Rouleau I, Sauerwein CH, Rosa C, Leroux JM, Gravel P, Valois K, Andermann F, Saint-Amour D, Lassonde M. Language lateralization in individuals with callosal agenesis: An fMRI study. Neuropsychologia 2011; 49:1987-95. [DOI: 10.1016/j.neuropsychologia.2011.03.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 11/24/2010] [Accepted: 03/22/2011] [Indexed: 11/26/2022]
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Chow EW, Ho A, Wei C, Voormolen EH, Crawley AP, Bassett AS. Association of schizophrenia in 22q11.2 deletion syndrome and gray matter volumetric deficits in the superior temporal gyrus. Am J Psychiatry 2011; 168:522-9. [PMID: 21362743 PMCID: PMC3283577 DOI: 10.1176/appi.ajp.2010.10081230] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Individuals with 22q11.2 deletion syndrome are known to be at high risk of developing schizophrenia. Previous imaging studies have provided limited data on the relation of schizophrenia expression in 22q11.2 deletion syndrome to specific regional brain volumetric changes. The authors hypothesized that the main structural brain finding associated with schizophrenia expression in 22q11.2 deletion syndrome, as for schizophrenia in the general population, would be gray matter volumetric deficits, especially in the temporal lobes. METHOD MR brain images from 29 patients with 22q11.2 deletion syndrome and schizophrenia and 34 comparison subjects with 22q11.2 deletion syndrome and no history of psychosis were analyzed using a voxel-based morphometry method that also yielded volumes for related region-of-interest analyses. The authors compared data from the two groups using an analysis of covariance model correcting for total intracranial volume, age, sex, IQ, and history of congenital cardiac defects. The false discovery rate threshold was set at 0.05 to account for multiple comparisons. RESULTS Voxel-based morphometry analyses identified significant gray matter reductions in the left superior temporal gyrus (Brodmann's area 22) in the schizophrenia group. There were no significant between-group differences in white matter or CSF volumes. Region-of-interest analyses showed significant bilateral gray matter volume reductions in the temporal lobes and superior temporal gyri in the schizophrenia group. CONCLUSIONS The structural brain expression of schizophrenia associated with the highly penetrant 22q11.2 deletion involves lower gray matter volumes in temporal lobe regions. These structural MRI findings in a 22q11.2 deletion syndrome form of schizophrenia are consistent with those from studies involving schizophrenia samples from the general population. The results provide further support for 22q11.2 deletion syndrome as a genetic subtype and as a useful neurodevelopmental model of schizophrenia.
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Exposure to parental verbal abuse is associated with increased gray matter volume in superior temporal gyrus. Neuroimage 2010; 54 Suppl 1:S280-6. [PMID: 20483374 DOI: 10.1016/j.neuroimage.2010.05.027] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 05/01/2010] [Accepted: 05/12/2010] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE Exposure to parental verbal aggression (PVA) during childhood increases risk for the development of psychopathology, particularly mood and anxiety disorders. Other forms of childhood abuse have been found to be associated with alterations in brain structure. The aim of this study was to ascertain whether exposure to PVA was associated with discernible effects on brain morphology. METHODS Optimized voxel-based morphometry was performed on 21 unmedicated, right-handed subjects (18-25 years) with histories of PVA and 19 psychiatrically healthy controls of comparable age and gender. Group differences in gray matter volume (GMV)--covaried by age, gender, parental education, financial stress, and total GMV--were assessed using high-resolution, T1-weighted, volumetric MRI data sets (Siemens 3T trio scanner). RESULTS GMV was increased by 14.1% in the left superior temporal gyrus (STG, BA 22) (P=0.004, corrected cluster level). GMV in this cluster was associated most strongly with levels of maternal (ß=0.544, P<0.0001) and paternal (ß=0.300, P<0.02) verbal aggression and inversely associated with parental education (ß=-0.577, P<0.0001). CONCLUSION Previous studies have demonstrated an increase in STG GMV in children with abuse histories, and found a reduction in fractional anisotropy in the arcuate fasciculus connecting Wernicke's and frontal areas in young adults exposed to PVA. These findings and the present results suggest that the development of auditory association cortex involved in language processing may be affected by exposure to early stress and/or emotionally abusive language.
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Relative utility for hemispheric lateralization of different clinical fMRI activation tasks within a comprehensive language paradigm battery in brain tumor patients as assessed by both threshold-dependent and threshold-independent analysis methods. Neuroimage 2010; 54 Suppl 1:S136-45. [PMID: 20380883 DOI: 10.1016/j.neuroimage.2010.03.082] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 03/25/2010] [Accepted: 03/29/2010] [Indexed: 11/23/2022] Open
Abstract
The aim of this study was to compare the relative effectiveness of 6 different commonly used language fMRI activation paradigms, including receptive and expressive, as well as semantic and phonological tasks, for hemispheric lateralization in brain tumor patients utilizing both threshold-dependent and threshold-independent approaches. We studied 46 right-handed patients with primary intra-axial brain tumors with BOLD fMRI on a 3-T MRI system. A linear fit of the laterality indices (LIs) as a function of the t-value (which varied from 2.0 to 6.5) was calculated and the slope (M) taken as measure of LI variability in the threshold-dependent LI approach; for the threshold-independent approach, the LIs were determined by comparing the integrated T-score weighted distributions of all positively task-correlated voxels of the left and the right hemispheric regions of interest. We demonstrated that silent word generation (SWG) and rhyming (R) were the two expressive tasks that provided the best hemispheric language lateralization in this group, based on concordant threshold-dependent and threshold-independent analyses. Furthermore, R (mean LI value=61.91, M=7.9±1.5) had a higher mean LI value and was less threshold-dependent than SWG (mean LI=52.97, M=11.40±0.64) for LI determination. SWG and R were able to provide effective language lateralization even in the subgroup of patients with lesions located in the left hemisphere and in the frontal or parietal lobes. The receptive language paradigms examined in this study (passive listening [PL], listening comprehension [LC], and reading comprehension [RC]) were less effective than SWG and R for language lateralization.
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Foki T, Beisteiner R. [Methodological problems with clinical functional MRI investigations]. Radiologe 2010; 50:104-9. [PMID: 20057982 DOI: 10.1007/s00117-009-1896-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During presurgical diagnostics clinical functional magnetic resonance imaging is increasingly being performed to improve the management of epilepsy and tumor patients. Rapid technical developments in fMRI technology continuously further new diagnostic applications. Safe clinical application requires a profound and critical handling of the various methodological problems inherent with this complex technique. This article reviews relevant problems and solutions for patient investigations up to the preparation of an individual clinical fMRI report.
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Affiliation(s)
- T Foki
- AG klinische fMRT, Universitätsklinik für Neurologie, Exzellenzzentrum Hochfeld-MR, Medizinische Universität Wien, Währinger Gürtel 18-20, A-1090 Wien, Osterreich
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