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Abstract:
Several different language paradigms have been developed to
generate activation maps using functional MRI. Normally these
studies are performed with volunteers or epilepsy patients. We had
the opportunity to test our language paradigm on an aphasic
patient: 69 year old male with a three week history of
disorientation and confusion. T1 weighted MRI scans showed a 2 cm
mass in the left parietal cortex. The patient, a verbose retired
engineer, could no longer read or write. Our language paradigm
required no reading and was designed for use with any presurgical
candidate regardless of etiology. One minute of "rest" was
alternated with one minute of "task" for a total of 4 minutes.
During "rest" the patient was told to concentrate on his breathing.
For the "task" the patient was instructed to non-verbally define
pre-selected words presented orally at a rate of one word every six
seconds. During the scanning session the patient seemed to
understand and perform according to verbal instructions but only
intermittently provided appropriate answers. In a 1.5 T Picker MR
scanner equipped with whole body echo planar gradients, BOLD
functional images were acquired. The parameters were: fifteen axial
slices of 5 mm, skip 1.5 mm, TE 40, TR 3,000 and FOV 45. Regions of
activation generated by a t-test were merged onto matched T1
weighted structural images. Areas of activation surrounded the
tumor. Using the information provided by the fMRI scan the surgeon
opted for radiation therapy rather risk permanent deficit with
resection.
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