Method for measuring neurovascular uncoupling in fMRI
Neurovascular uncoupling that causes fMRI data to underestimate viable neuronal activity in the brain is detected and indicated to assist in pre-surgical planning. Tasks associated with the cortical region in question are performed while the fMRI measurement of brain activity is measured and the same tasks are performed while task performance is measured directly. Neurovascular uncoupling is detected and indicated by comparing the results of fMRI measurement and direct measurement.
1. A method for detecting neurovascular uncoupling in the brain of a subject, the steps comprising:
a) acquiring fMRI data from the subject with a magnetic resonance imaging system that measures brain activity in response to at least one of a selected stimulus applied to the subject and a selected task performed by the subject;
b) transforming the fMRI data to a first map;
c) measuring a behavioral response of the subject to the at least one selected stimulus and selected task performed by the subject;
d) creating a second map based on the measured behavioral response in step c);
e) comparing the first map created in step b) with the second map created in step d); and
f) indicating a difference between the first map and the second map as neurovascular uncoupling.
2. The method as recited in claim 1 in which step a) measures the subject's field of vision and step b) includes
producing a functional field map from the acquired fMRI data that indicates the locations in the subject's visual field that correspond to locations of indicated brain activity.
3. The method as recited in claim 2 in which step c) includes measuring the subject's field of view and step d) includes producing a visual field map that indicates the locations in the subject's visual field which the subject can actually see.
4. The method as recited in claim 1 in which step f) includes:
f)i) displaying an anatomical image of the subject's brain;
f)ii) converting the difference regions between the two maps relating to neurovascular uncoupling to corresponding regions in the image of the brain of i); and
f)iii) displaying on the anatomical image regions where neurovascular uncoupling is indicated.
5. The method as recited in claim 1 which includes:
g) acquiring MRI data from the subject and reconstructing therefrom an anatomical image of the subject's brain;
h) displaying regions of brain activity on the anatomical image indicated by the acquired fMRI data; and
step f) includes displaying regions of neurovascular uncoupling on the anatomical image.
6. The method as recited in claim 1 in which step a) measures the subject's response to at least one of active movement and passive stimulation at a plurality of locations on the subject's body; and step b) includes:
producing a functional field map from the acquired fMRI data that indicates the locations on the subject's body that correspond to locations of indicated brain activity.
7. The method as recited in claim 6 in which step c) includes measuring the subject's response to the at least one of active movement and the passive stimulation and step d) producing a sensory map that indicates the locations on the subject's body which are responsive.
8. The method as recited in claim 1 in which step b) includes producing a functional field map from the acquired fMRI data that may be used in step e) to compare response of the subject to direct measurements.
9. The method as recited in claim 1 in which step f) includes indicating neurovascular uncoupling when the second map includes data in a portion of the map and the first map has an absence of data in a corresponding portion of the second map.