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Reliability of fMRI for motor and language cortex activation in brain tumor patients
NemoImage
13, Number
6, 2001,
Part 2 of 2 Parts 10
E bl@
SENSORIMOTOR
Reliability of fMRI for motor and languagecortex activation in brain tumor patients John Haller*t,
Timothy Ryken*$&
Rahul Aggarwahl*j-,
Lizann Bolinger*t
*University of Iowa TDepartment of Radiology $Department of Surgery §Division of Neurosurgery Introduction Functional magnetic resonance imaging (fMRI) was used to map brain activity in patients with brain tumors and normal subjects. The purpose of this study was to reliably activate areas of language and motor cortex and demonstrate consistency of results. Methods Three language tasks and/or a motor task (hand squeeze) were performed using a block design in eight normal subjects and three patients with brain tumors. A 30 second hand-squeeze, and 30 second rest periods were repeated for 5 minutes. During the three language tasks subjects were asked to 1) think of words that began with a single letter 2) Complete a three letter word stem and 3) generate a verb that was associated with a noun. Echo planar images (EPI - 3 seconds duration, 250 x 250 mm FOV, 128 x 128 matrix, 5 slices with 5 mm thickness) and anatomic images were performed on a GE 1.5 T Signa CV/i scanner. EPI slices were positioned over the superior central sulcus and anterior - inferior frontal cortex (Broca’s area). To evaluate repeatability of functional imaging of brain activity, scans were repeated during the same session for three normal subjects, and between two sessions for one normal subject. Different language tasks were used to demonstrate the consistency (overlap) of brain areas activated during these tasks. To demonstrate the reliability of the tasks to activate similar regions between subjects, correlation images from different subjects were non-linearly warped into a standard atlas space. Correlation images of the brain were generated with a criterion threshold of r= 0.4 for language and motor cortex activation. ReSldtS
Figure 1. fMRI correlation (r = 0.7) of motor cortex activity in an axial slice during right hand squeeze in a single normal subject.
Normal subjects showed activation of similar frontal regions for the three language tasks, with the word-stem completion task showing the most robust activation. Similarly, identical tasks repeated during the same session (or on different days for one subject) showed overlapping regions of brain activity within subjects. Motor cortex was consistently activated in all five subjects and a two patients with brain tumors. A third patient with a large tumor extending into prefrontal cortex, anterior to the central sulcus failed to show the criterion activation (r = 0.4) during two of the language tasks, and was unable to complete the motor task due to paralysis. Discussion In summary, activity in left frontal cortex was correlated with performance of language tasks in normal subjects. Normal subjects also showed correlation of motor cortex activity (typically greater than r = 0.7) during the hand squeezing task, and two patient’s with brain tumors also activated right motor cortex during hand squeezing. A third patient was unable to activate left hemisphere regions, perhaps due to the extent of his tumor which invaded regions of frontal cortex. This paralysis of his right hand. The results demonstrate reliability of fMRI over time, between subjects, and difficulties of scanning brain tumor patients will need to be solved in order to use fMRI of eloquent cortex.
s1179
Figure 2. Three language tasks performed by normal subjects show activation of left frontal cortical areas in multiple images nonlinearly warped to an atlas. latter patient
also had impaired
speech
and
between language tasks. The logistics and as a reliable clinical tool for the delineation
13, Number
6, 2001,
Part 2 of 2 Parts 10
E bl@
SENSORIMOTOR
Reliability of fMRI for motor and languagecortex activation in brain tumor patients John Haller*t,
Timothy Ryken*$&
Rahul Aggarwahl*j-,
Lizann Bolinger*t
*University of Iowa TDepartment of Radiology $Department of Surgery §Division of Neurosurgery Introduction Functional magnetic resonance imaging (fMRI) was used to map brain activity in patients with brain tumors and normal subjects. The purpose of this study was to reliably activate areas of language and motor cortex and demonstrate consistency of results. Methods Three language tasks and/or a motor task (hand squeeze) were performed using a block design in eight normal subjects and three patients with brain tumors. A 30 second hand-squeeze, and 30 second rest periods were repeated for 5 minutes. During the three language tasks subjects were asked to 1) think of words that began with a single letter 2) Complete a three letter word stem and 3) generate a verb that was associated with a noun. Echo planar images (EPI - 3 seconds duration, 250 x 250 mm FOV, 128 x 128 matrix, 5 slices with 5 mm thickness) and anatomic images were performed on a GE 1.5 T Signa CV/i scanner. EPI slices were positioned over the superior central sulcus and anterior - inferior frontal cortex (Broca’s area). To evaluate repeatability of functional imaging of brain activity, scans were repeated during the same session for three normal subjects, and between two sessions for one normal subject. Different language tasks were used to demonstrate the consistency (overlap) of brain areas activated during these tasks. To demonstrate the reliability of the tasks to activate similar regions between subjects, correlation images from different subjects were non-linearly warped into a standard atlas space. Correlation images of the brain were generated with a criterion threshold of r= 0.4 for language and motor cortex activation. ReSldtS
Figure 1. fMRI correlation (r = 0.7) of motor cortex activity in an axial slice during right hand squeeze in a single normal subject.
Normal subjects showed activation of similar frontal regions for the three language tasks, with the word-stem completion task showing the most robust activation. Similarly, identical tasks repeated during the same session (or on different days for one subject) showed overlapping regions of brain activity within subjects. Motor cortex was consistently activated in all five subjects and a two patients with brain tumors. A third patient with a large tumor extending into prefrontal cortex, anterior to the central sulcus failed to show the criterion activation (r = 0.4) during two of the language tasks, and was unable to complete the motor task due to paralysis. Discussion In summary, activity in left frontal cortex was correlated with performance of language tasks in normal subjects. Normal subjects also showed correlation of motor cortex activity (typically greater than r = 0.7) during the hand squeezing task, and two patient’s with brain tumors also activated right motor cortex during hand squeezing. A third patient was unable to activate left hemisphere regions, perhaps due to the extent of his tumor which invaded regions of frontal cortex. This paralysis of his right hand. The results demonstrate reliability of fMRI over time, between subjects, and difficulties of scanning brain tumor patients will need to be solved in order to use fMRI of eloquent cortex.
s1179
Figure 2. Three language tasks performed by normal subjects show activation of left frontal cortical areas in multiple images nonlinearly warped to an atlas. latter patient
also had impaired
speech
and
between language tasks. The logistics and as a reliable clinical tool for the delineation