Signal intensity of perirolandic cortex identifies the central sulcus on double inversion recovery MRI

Background Identification of the central sulcus can require inspection of subtle differences or require certain pulse sequences. This study identifies the central sulcus by signal intensity on Double Inversion Recovery (DIR) images in multiple anatomic locations and imaging planes. Methods 49 patients (98 hemispheres) were retrospectively reviewed by three neuroradiologists and one radiology resident. The central sulcus was compared to the surrounding sulci for differences in signal intensity at axial hand knob, axial operculum, and lateral convexity sagittal images (294 locations) on DIR images. The use of the 'disappearing central sulcus sign' where the window level is increased at constant width and black/white inversion were also assessed. Results In 49 patients (22 female, 27 male; median age 36 years), the central sulcus cortex signal intensity was lower than adjacent sulci with a frequency of 90/98 (91.8%) at the axial hand knob level, 68/98 (69.4%) at the axial operculum level, and 76/98 (77.5%) at the sagittal level. With black and white inversion, the frequencies were of 96/98 (98%), 92/98 (94%), and 87/98 (89%). The central sulcus was the first to disappear at all three levels with high degrees of inter-reader agreement (86%-99%). Traditional anatomic landmarks were absent or conflicting in seven hemispheres (5 patients). The central sulcus was identified by DIR signal intensity in all seven hemispheres. Conclusions The central sulcus can be identified by differences in signal intensity of the peri-rolandic cortex on DIR. Use of black/white inversion and the disappearing central sulcus sign may further facilitate identification.