Patterns of functional magnetic resonance imaging activation in association with structural lesions in the rolandic region: a classification system

2001 ◽  
Vol 94 (6) ◽  
pp. 946-954 ◽  
Author(s):  
Alexandre C. Carpentier ◽  
R. Todd Constable ◽  
Michael J. Schlosser ◽  
Alain de Lotbinière ◽  
Joseph M. Piepmeier ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Motor Cortex ◽  
Motor Skills ◽  
Classification Scheme ◽  
Surgical Intervention ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Rolandic Region ◽  
Fine Print

Object. Functional magnetic resonance (fMR) imaging of the motor cortex is a potentially powerful tool in the preoperative planning of surgical procedures in and around the rolandic region. Little is known about the patterns of fMR imaging activation associated with various pathological lesions in that region or their relation to motor skills before surgical intervention. Methods. Twenty-two control volunteers and 44 patients whose pathologies included arteriovenous malformations (AVMs; 16 patients), congenital cortical abnormalities (11 patients), and tumors (17 patients) were studied using fMR imaging and a hand motor task paradigm. Activation maps were constructed for each participant, and changes in position or amplitude of the motor activation on the lesion side were compared with the activation pattern obtained in the contralateral hemisphere. A classification scheme of plasticity (Grades 1–6) based on interhemispheric pixel asymmetry and displacement of activation was used to compare maps between patients, and relative to hand motor dexterity and/or weakness. There was 89.4% interobserver agreement on classification of patterns of fMR imaging activation. Displacement of activation by mass effect was more likely with tumors. Cortical malformations offer a much higher functional reorganization than AVMs or tumors. High-grade plasticity is recruited to compensate for severe motor impairment. Conclusions. Pattern modification of fMR imaging activation can be systematized in a classification of motor cortex plasticity. This classification has shown good correlation among grading, brain lesions, and motor skills. This proposal of a classification scheme, in addition to facilitating data collection and processing from different institutions, is well suited for comparing risks associated with surgical intervention and patterns of functional recovery in relation to preoperative fMR imaging categorization. Such studies are underway at the authors' institution.

Functional magnetic resonance imaging of sensory and motor cortex: comparison with electrophysiological localization

1995 ◽  
Vol 83 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Aina Puce ◽  
R. Todd Constable ◽  
Marie L. Luby ◽  
Gregory McCarthy ◽  
Anna C. Nobre ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Magnetic Resonance ◽  
Motor Cortex ◽  
Mr Imaging ◽  
Sensorimotor Cortex ◽  
Functional Magnetic Resonance ◽  
Planar Imaging ◽  
Content Type ◽  
Functional Mr Imaging ◽  
Fine Print

✓ Functional magnetic resonance (MR) imaging was performed using a 1.5-tesla MR system to localize sensorimotor cortex. Six neurologically normal subjects were studied by means of axial gradient-echo images with a motor task and one or more sensory tasks: 1) electrical stimulation of the median nerve; 2) continuous brushing over the thenar region; and 3) pulsed flow of compressed air over the palm and digits. An increased MR signal was observed in or near the central sulcus, consistent with the location of primary sensory and motor cortex. Four patients were studied using echo planar imaging sequences and motor and sensory tasks. Three patients had focal refractory seizures secondary to a lesion impinging on sensorimotor cortex. Activation seen on functional MR imaging was coextensive with the location of the sensorimotor area determined by evoked potentials and electrical stimulation. Functional MR imaging provides a useful noninvasive method of localization and functional assessment of sensorimotor cortex.

Sources of error in comparing functional magnetic resonance imaging and invasive electrophysiological recordings

2000 ◽  
Vol 93 (2) ◽  
pp. 214-223 ◽  
Author(s):  
Derek L. G. Hill ◽  
Andrew D. Castellano Smith ◽  
Andrew Simmons ◽  
Calvin R. Maurer ◽  
Timothy C. S. Cox ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Healthy Volunteers ◽  
Hand Movement ◽  
Epileptogenic Zone ◽  
Imaging Data ◽  
Functional Magnetic Resonance ◽  
Reliable Technique ◽  
Content Type ◽  
The Brain ◽  
Fine Print

Object. Several authors have recently reported studies in which they aim to validate functional magnetic resonance (fMR) imaging against the accepted gold standard of invasive electrophysiological monitoring. The authors have conducted a similar study, and in this paper they identify and quantify two characteristics of these data that can make such a comparison problematic.Methods. Eight patients in whom surgery for epilepsy was performed and five healthy volunteers underwent fMR imaging to localize the part of the sensorimotor cortex responsible for hand movement. In the patient group subdural electrode mats were subsequently implanted to identify eloquent regions of the brain and the epileptogenic zone. The fMR imaging data were processed to correct for motion during the study and then registered with a postimplantation computerized tomography (CT) scan on which the electrodes were visible. The motion during imaging in the two groups studied, and the deformation of the brain between the preoperative images and postoperative scans were measured.The patients who underwent epilepsy surgery moved significantly more during fMR imaging experiments than healthy volunteers performing the same motor task. This motion had a particularly increased out-of-plane component and was significantly more correlated with the stimulus than in the volunteers. This motion was especially increased when the patients were performing a task on the side affected by the lesion. The additional motion is hard to correct and substantially degrades the quality of the resulting fMR images, making it a much less reliable technique for use in these patients than in others. Also, the authors found that after electrode implantation, the brain surface can shift more than 10 mm relative to the skull compared with its preoperative location, substantially degrading the accuracy of the comparison of electrophysiological measurements made in the deformed brain and fMR studies obtained preoperatively.Conclusions. These two findings indicate that studies of this sort are currently of limited use for validating fMR imaging and should be interpreted with care. Additional image analysis research is necessary to solve the problems caused by patients' motion and brain deformation.

Clinical application of functional magnetic resonance imaging in presurgical identification of the central sulcus

1998 ◽  
Vol 88 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Jesús Pujol ◽  
Gerardo Conesa ◽  
Joan Deus ◽  
Luis López-Obarrio ◽  
Fabián Isamat ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Three Dimensional ◽  
Functional Magnetic Resonance ◽  
Central Sulcus ◽  
Clinical Context ◽  
Content Type ◽  
Sensorimotor Region ◽  
Specific Factors ◽  
Eloquent Cortex ◽  
Fine Print

Object. The authors sought to evaluate the advantages and limitations of functional magnetic resonance (fMR) imaging when it was used regularly in the clinical context to identify the central sulcus. Methods. A 1.5-tesla MR system comprising a spoiled gradient recalled acquisition in the steady-state functional sequence and a cross-hand cancellation analysis method were used to evaluate 50 surgical candidates with centrally located space-occupying lesions in the brain. Three-dimensional (3-D) models of the patient's head and brain showing the relative position of the tumor and the eloquent cortex were obtained in each case. A selective and reproducible focal activation was found, indicating the probable central sulcus position in 41 patients (82%). Direct cortical stimulation confirmed the fMR findings in 100% of 22 intraoperatively assessed patients. Failure to identify the central sulcus occurred in 18% of cases and was mainly a consequence of intrinsic damage in the primary sensorimotor region that resulted in severe hand paresis. Conclusions. Although specific factors were identified that contributed to reduced sensitivity of fMR imaging in the clinical context, the present study supports functional assessment and 3-D representation of specific surgical situations as generally feasible in common practice.

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.

Localization of human frontal eye fields: anatomical and functional findings of functional magnetic resonance imaging and intracerebral electrical stimulation

2001 ◽  
Vol 95 (5) ◽  
pp. 804-815 ◽  
Author(s):  
Elie Lobel ◽  
Philippe Kahane ◽  
Ute Leonards ◽  
Marie-Hélène Grosbras ◽  
Stéphane Lehéricy ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Magnetic Resonance ◽  
3 Tesla ◽  
Frontal Eye Fields ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
Cortical Areas ◽  
Fine Print

Object. The goal of this study was to investigate the anatomical localization and functional role of human frontal eye fields (FEFs) by comparing findings from two independently conducted studies. Methods. In the first study, 3-tesla functional magnetic resonance (fMR) imaging was performed in 14 healthy volunteers divided into two groups: the first group executed self-paced voluntary saccades in complete darkness and the second group repeated newly learned or familiar sequences of saccades. In the second study, intracerebral electrical stimulation (IES) was performed in 38 patients with epilepsy prior to surgery, and frontal regions where stimulation induced versive eye movements were identified. These studies showed that two distinct oculomotor areas (OMAs) could be individualized in the region classically corresponding to the FEFs. One OMA was consistently located at the intersection of the superior frontal sulcus with the fundus of the superior portion of the precentral sulcus, and was the OMA in which saccadic eye movements could be the most easily elicited by electrical stimulation. The second OMA was located more laterally, close to the surface of the precentral gyrus. The fMR imaging study and the IES study demonstrated anatomical and stereotactic agreement in the identification of these cortical areas. Conclusions. These findings indicate that infracentimetric localization of cortical areas can be achieved by measuring the vascular signal with the aid of 3-tesla fMR imaging and that neuroimaging and electrophysiological recording can be used together to obtain a better understanding of the human cortical functional anatomy.

Patterns of lateral sensory cortical activation determined using functional magnetic resonance imaging

1998 ◽  
Vol 89 (5) ◽  
pp. 769-779 ◽  
Author(s):  
Charles J. Hodge ◽  
Sean C. Huckins ◽  
Nikolaus M. Szeverenyi ◽  
Michael M. Fonte ◽  
Jacob G. Dubroff ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Imaging Techniques ◽  
Cortical Activation ◽  
The Other ◽  
Functional Magnetic Resonance ◽  
Cortical Function ◽  
Content Type ◽  
And Cluster Analysis ◽  
Student’S T ◽  
Fine Print

Object. Functional magnetic resonance (fMR) imaging was performed in human volunteers to determine the lateral perisylvian cortical areas activated by innocuous cutaneous stimulation. Methods. Eight volunteers who underwent 53 separate experiments form the basis of this report. Eight contiguous coronal slices were obtained using echoplanar fMR imaging techniques while participants were at rest and while somatosensory activation stimuli consisting of vibration or air puffs were delivered to various body areas. The data were analyzed using Student's t-test and cluster analysis to determine significant differences between the resting and activated states. The findings were as follows: the areas in the lateral cortex activated by the sitmuli were the primary sensory cortex (SI), the second somatosensory area (SII), the insula, the superior parietal lobule, and the retroinsular parietal operculum (RIPO). Somatotopy was demonstrable in SI but not in the other areas identified. There was a surprisingly low correlation between the amount of cortex activated in the various areas, which could mean separate inputs and functions for the areas identified. The highest correlation was found between activity in SII and RIPO (0.69). Conclusions. The authors maintain that fMR imaging can be used to identify multiple lateral somatosensory areas in humans. Somatotopy is demonstrated in SI but not in the other lateral cortical sensory areas. The correlations between the amounts of cortex activated in the different lateral sensory areas are low. Recognition of the multiple lateral sensory areas is important both for understanding sensory cortical function and for safe interpretation of studies designed to identify the central sulcus by activating SI.

Presurgical motor and somatosensory cortex mapping with functional magnetic resonance imaging and positron emission tomography

1999 ◽  
Vol 91 (6) ◽  
pp. 915-921 ◽  
Author(s):  
Richard G. Bittar ◽  
André Olivier ◽  
Abbas F. Sadikot ◽  
Frederick Andermann ◽  
G. Bruce Pike ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Emission Tomography ◽  
Functional Magnetic Resonance ◽  
Central Sulcus ◽  
Content Type ◽  
Positron Emission ◽  
Pet Scanning ◽  
Functional Localization ◽  
Fine Print

Object. Accurate identification of eloquent cortex is important to ensure that resective surgery in the region surrounding the central sulcus is performed with minimum risk of permanent neurological deficit. Functional localization has traditionally been accomplished using intraoperative cortical stimulation (ICS). However, this technique suffers from several disadvantages that make the development and validation of noninvasive methods desirable. Functional localization accomplished by activation studies in which positron emission tomography (PET) scanning and the tracer [15O]H2O have been used has been shown to correlate well with the results of ICS. Another noninvasive method for functional localization is functional magnetic resonance (fMR) imaging. We compared the locations of activation peaks obtained in individual patients using fMR and [15O]H2O PET imaging.Methods. Twenty-six combined PET activation—fMR imaging studies were performed in 11 patients who were admitted for evaluation before undergoing surgery in the region surrounding the central sulcus. The PET scans were obtained using bolus injections of the cerebral blood flow tracer [15O]H2O (10 mCi). Multislice T2*-weighted gradient-echo echoplanar images were acquired using a 1.5-tesla MR imaging system. Activation maps were aligned with anatomical MR images and transformed into stereotactic space, after which the locations of activation peaks obtained using both modalities were compared. The average distance between activation peaks obtained using fMR imaging and those obtained using PET imaging was 7.9 ± 4.8 mm (p > 0.05), with 96% of the peaks being located on either the same or adjacent sulci and gyri. Overlapping of voxels activated by each modality occurred in 92% of the studies. Functional MR imaging failed to activate the primary sensorimotor cortex in one study and produced results that were ambiguous in the clinical setting in three cases.Conclusions. Overall, fMR imaging produced activation that correlated well with that obtained using PET scanning. Discrepancies between the sites of activation identified using these two techniques may reflect differences in their physiological bases.

Functional magnetic resonance imaging and control over the biceps muscle after intercostal—musculocutaneous nerve transfer

2003 ◽  
Vol 98 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Martijn J. A. Malessy ◽  
Dick Bakker ◽  
Ad J. Dekker ◽  
J. Gert van Dijk ◽  
Ralph T. W. M. Thomeer
Keyword(s):  
Magnetic Resonance ◽  
Nerve Transfer ◽  
Biceps Muscle ◽  
Functional Magnetic Resonance ◽  
Common Input ◽  
Content Type ◽  
Input Activity ◽  
Input Response ◽  
And Control ◽  
Fine Print

Object. Recent progress in the understanding of cerebral plastic changes that occur after an intercostal nerve (ICN)—musculocutaneous nerve (MCN) transfer motivated a study with functional magnetic resonance (fMR) imaging to map reorganization in the primary motor cortex. Methods. Eleven patients with traumatic root avulsions of the brachial plexus were studied. Nine patients underwent ICN—MCN transfer to restore biceps function and two patients were studied prior to surgery. The biceps muscle recovered well in seven patients who had undergone surgery and remained paralytic in the other two patients. Maps of neural activity within the motor cortex were generated for both arms in each patient by using fMR imaging, and the active pixels were counted. The motor task consisted of biceps muscle contraction. Patients with a paralytic biceps were asked to contract this muscle virtually. The location and intensity of motor activation of the seven surgically treated arms that required good biceps muscle function were compared with those of the four arms with a paralytic biceps and with activity obtained in the contralateral hemisphere regulating the control arms. Activity could be induced in the seven surgically treated patients whose biceps muscles had regained function and was localized within the primary motor area. In contrast, activity could not be induced in the four patients whose biceps muscles were paralytic. Neither the number of active pixels nor the mean value of their activations differed between the seven arms with good biceps function and control arms. The weighted center of gravity of the distribution of activity also did not appear to differ. Conclusions. Reactivation of the neural input activity for volitional biceps control after ICN—MCN transfer, as reflected on fMR images, is induced by successful biceps muscle reinnervation. In addition, the restored input activity does not differ from the normal activity regulating biceps contraction and, therefore, has MCN acceptor qualities. After ICN—MCN transfer, cerebral activity cannot reach the biceps muscle following the normal nervous system pathway. The presence of a common input response between corticospinal neurons of the ICN donor and the MCN acceptor seems crucial to obtain a functional result after transfer. It may even be the case that a common input response between donor and acceptor needs to be present in all types of nerve transfer to become functionally effective.

Comparative localization of auditory comprehension by using functional magnetic resonance imaging and cortical stimulation

1999 ◽  
Vol 91 (4) ◽  
pp. 626-635 ◽  
Author(s):  
Michael J. Schlosser ◽  
Marie Luby ◽  
Dennis D. Spencer ◽  
Issam A. Awad ◽  
Gregory McCarthy
Keyword(s):  
Magnetic Resonance ◽  
Language Processing ◽  
Cortical Stimulation ◽  
Spatial Extent ◽  
Auditory Comprehension ◽  
Functional Magnetic Resonance ◽  
Language Mapping ◽  
Technical Problems ◽  
Content Type ◽  
Fine Print

Object. The authors previously described a functional magnetic resonance (fMR) imaging task for the localization of auditory comprehension in which focal activation of posterior temporal and inferior frontal regions of the left hemisphere was reliably demonstrated. Because this study was conducted in neurologically normal volunteers, it was not possible to determine whether the activated regions were critical to the performance of language tasks; that is, whether the fMR imaging activations provided a valid measure of language processing. A direct comparison of fMR imaging language activation with cortical stimulation must be completed before it can be used with confidence in presurgical planning, and this comparison is performed in the present study.Methods. The authors report on a series of 33 consecutive patients who underwent dominant hemisphere resection and in whom fMR imaging mapping of auditory comprehension was performed at the Yale neurosurgical program.In 23 of the 33 patients fMR imaging activation was consistent with the typical results obtained in normal participants in the earlier study. In 16 of these 23 patients language mapping was performed using either intra- or extraoperative cortical stimulation. Cortical stimulation failed to localize language areas in two of the 16 patients. Electrical stimulation that was performed in proximity to the fMR image activations interfered with auditory comprehension, object naming, or speech production in 12 of the remaining 14 patients. Five of the 10 cases in which evocation of reliable fMR imaging activation failed were attributable to technical problems and/or patient head movement.Conclusions. Cortical stimulation results and fMR imaging findings were consistent in all but two patients. However, the spatial extent of the activation produced by fMR imaging and the spatial extent of stimulation-induced language disruption that was caused by direct cortical stimulation did not always correspond. Problems in defining the extent of activation by both methods are discussed.

Thalamic stimulation and functional magnetic resonance imaging: localization of cortical and subcortical activation with implanted electrodes

1999 ◽  
Vol 90 (3) ◽  
pp. 583-590 ◽  
Author(s):  
Ali R. Rezai ◽  
Andres M. Lozano ◽  
Adrian P. Crawley ◽  
Michael L. G. Joy ◽  
Karen D. Davis ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Somatosensory Cortex ◽  
Clinical Effects ◽  
Functional Magnetic Resonance ◽  
Electrode Implantation ◽  
Content Type ◽  
Functional Mr Imaging ◽  
Fine Print ◽  
Deep Brain

✓ The utility of functional magnetic resonance (fMR) imaging in patients with implanted thalamic electrodes has not yet been determined. The aim of this study was to establish the safety of performing fMR imaging in patients with thalamic deep brain stimulators and to determine the value of fMR imaging in detecting cortical and subcortical activity during stimulation.Functional MR imaging was performed in three patients suffering from chronic pain and two patients with essential tremor. Two of the three patients with pain had undergone electrode implantation in the thalamic sensory ventralis caudalis (Vc) nucleus and the other had undergone electrode implantation in both the Vc and the periventricular gray (PVG) matter. Patients with tremor underwent electrode implantation in the ventralis intermedius (Vim) nucleus. Functional MR imaging was performed during stimulation by using a pulse generator connected to a transcutaneous extension lead. Clinically, Vc stimulation evoked paresthesias in the contralateral body, PVG stimulation evoked a sensation of diffuse internal body warmth, and Vim stimulation caused tremor arrest.Functional images were acquired using a 1.5-tesla MR imaging system. The Vc stimulation at intensities provoking paresthesias resulted in activation of the primary somatosensory cortex (SI). Stimulation at subthreshold intensities failed to activate the SI. Additional stimulation-coupled activation was observed in the thalamus, the secondary somatosensory cortex (SII), and the insula. In contrast, stimulation of the PVG electrode did not evoke paresthesias or activate the SI, but resulted in medial thalamic and cingulate cortex activation. Stimulation in the Vim resulted in thalamic, basal ganglia, and SI activation.An evaluation of the safety of the procedure indicated that significant current could be induced within the electrode if a faulty connecting cable (defective insulation) came in contact with the patient. Simple precautions, such as inspection of wires for fraying and prevention of their contact with the patient, enabled the procedure to be conducted safely. Clinical safety was further corroborated by performing 86 MR studies in patients in whom electrodes had been implanted with no adverse clinical effects.This is the first report of the use of fMR imaging during stimulation with implanted thalamic electrodes. The authors' findings demonstrate that fMR imaging can safely detect the activation of cortical and subcortical neuronal pathways during stimulation and that stimulation does not interfere with imaging. This approach offers great potential for understanding the mechanisms of action of deep brain stimulation and those underlying pain and tremor generation.

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