fMRI enables identifying areas of brain activity as well as the white matter fibers connecting these areas. Identification of these areas and fibers prior to operation is highly important in preventing damage to essential functions, such as language and movement. Though there is much knowledge regarding the mapping of the brain, the exact location of each area is different from one person to another. Therefore, when preparing for surgery, functional mapping is required. In addition, the fMRI test enables determining the lateralization of language in a non-invasive manner.
The fMRI unit works together with neurosurgeons and creates a specific testing sequence for each patient according to the planned operation. It is also important to fit the test to the patient’s abilities: there are tests adapted for children as well as versions in different languages.
The results are used in deciding whether to operate or not, in planning the operation, and also during the operation. We provide the surgeon with a map containing activity regions and relevant fibers. The map is uploaded to the navigation system used during surgery, so that the surgeon can see the relation between the operated area and the important activity regions during the operation (in the figure you can see the SLF that connects regions involved in language processing surrounding a tumour in the frontal lobe).
During the test, the patient is required to perform various tasks, such as moving their hands and feet, looking at pictures, reading and building sentences. Identifying activity regions requires the cooperation of the patient, as without performing the tasks, the test is useless. Before the test we instruct the patients and ensure they experience no difficulty in performing the tasks.
When the functional test is completed, we conduct structural scans and a DTI scan for identification of white matter fibers.
The test takes between 40 minutes to an hour and a half. The quality of the results depends on the patient’s cooperation, as well as the type of injury and its location.