For most patients, an MRI scan is administered the day they arrive for surgery. An intra-operative ultrasound is used in conjunction with the operating microscope and the MRI-based intra-operative navigation system to look at the brain.
Figure 1 shows the ultrasound being used to delineate the tumor prior to opening the coverings of the brain (the dura).
Figure 2 shows a combination ultrasound and vascular Doppler image of the tumor. This enables visualization of the tumor and the surrounding blood vessels.
From the MRI scanner, the patient is transferred to the pre-operative area, where an IV is administered under the care of an operating room nurse and anesthesiologist. From there, the patient is taken into the operating room.
The patient is then placed under anesthesia. Motor mapping and sensory mapping can be performed with the patient under general anesthesia.
Some mapping, such as language mapping, require the patient to be awake during the mapping. In such cases, the patient is kept under anesthesia (asleep) except during the mapping part of the procedure.
(For more on mapping, see
Functional Brain Mapping)