We evaluated the applicability of functional MR imaging overlaid onto brain
images superimposed venography for neurosurgical identification of the cen
tral sulcus. In 20 volunteers and 12 patients with brain tumors located aro
und the sensorimotor cortex, gradient echo and large flip angle functional
MR image was performed to allow visualization of flow effect and susceptibi
lity related changes in relative large vein by motor hand task. Functional
MR image acquired was overlaid on 3D anatomical image with 3D venography. B
ased on the 3D mapping, intra-operative cortical somatosensory evoked poten
tials (SEPs) were recorded. The significant activation area obtained from f
unctional MR imaging was projected on an ascending cortical vein in 16 volu
nteers (80%) and 10 patients (83%). Comparing the anatomical activation map
with visual inspection of the exposed cortical surface made it easy to ide
ntify the activation area during surgery. The cortical veins in 9 of 10 wer
e validated as a central vein by intra-operative cortical recording of SEPs
. Combination of functional MR imaging overlaid onto 3D anatomical image wi
th venography and intra-operative SEPs permitted rapid and accurate localiz
ation of the central sulcus during surgery.