Abstract
INTRODUCTION Several radiographic methods exist to identify the Rolandic Sulcus (RS). The radiographic relationship between the RS and the central insular sulcus (CIS), specifically on magnetic resonance imaging (MRI), has not been studied. METHODS We reviewed one hundred consecutive normal MRI studies performed at our institution (Sept to Oct 2019). Sagittal and axial FLAIR and T2 sequences were chosen for the best sulcal anatomy. The first step was to identify all the insular sulci of the insular gray matter on the sagittal images. A straight line was then drawn from the CIS to the dorsal cortical surface, and the sulcus in continuity with the CIS was marked. The second step was to confirm the RS by comparing the location of the hand motor area (omega sign or hand knob sign) on the axial and sagittal scans. RESULTS We have reviewed 1233 consecutive MRIs, of which 100 normal MRI studies were included for review (200 hemispheres). The median age of patients was 49.5 years [18-81 years] and 66 patients (66%) were females. The CIS was easily identified in 198 hemispheres (99%). Out of the 198 hemispheres, the CIS was in continuity with the presumed RS in 191 hemispheres (96.5%). This was confirmed in all cases by correlating the presumed RS with the hand motor area (HMA) on axial images. In the remaining seven, the CIS was in continuity with the precentral sulcus (PCS) in 5 hemispheres (2.5%) and with the postcentral sulcus (PoCS) in two hemispheres (1%). The hand motor area (HMA), identified as a hook or a C-shaped structure on sagittal images, was visible in the same section as the CIS in 166 hemispheres (86.9%), but medially in the remaining 25 hemispheres (13.1%). The CIS/RS correlation, however, remained consistent in all instances. CONCLUSION The CIS can be utilized as a highly reliable radiographic landmark for the identification of the RS. Identification of the HMA can also be done reliably with this method.