THE CENTRAL SULCAL VEIN - A LANDMARK FOR IDENTIFICATION OF THE CENTRAL SULCUS USING FUNCTIONAL MAGNETIC-RESONANCE-IMAGING

The authors evaluated the anatomical location of the central sulcus (C S) in 24 cerebral hemispheres (eight in which tumors were located cent rally, 16 in controls) using: 1) classic anatomical landmarks seen on magnetic resonance (MR) imaging (24 hemispheres); 2) functional MR ima ging (24 hemispheres); and 3) intraoperative electrical stimulation ma pping (eight hemispheres). On MR imaging the CS was identified with ce rtainty in 79% of hemispheres (four of eight in patients, 15 of 16 in controls). Functional MR imaging identified a parenchymal ''motor hand area'' in only 83% (20 of 24 hemispheres; five of eight in patients, 15 of 16 in controls); this area was located in the precentral gyrus i n 16 (80%) of 20, additionally in the postcentral gyrus in 10 (50%) of 20, and exclusively in the postcentral gyrus in four (20%) of 20. In contrast, functional MR imaging detected one to three sulcal veins pre sumably draining blood from the adjacent motor hand area in 100% (24 o f 24) of the hemispheres studied, and anatomical MR imaging and intrao perative mapping localized these veins in the CS. It is concluded that sulcal veins lying deep within the CS: 1) drain activated blood from the adjacent pre- or postcentral cortex during performance of a motor hand task; 2) can be identified easily with functional MR imaging; and 3) are an anatomical landmark for noninvasive indentification of the CS and thus the sensorimotor strip. The detection of these veins provi des a more consistent landmark than the detection of parenchymal motor areas by functional MR imaging; this technique may be used when class ic anatomical landmarks fail to identify the sensorimotor strip.