Schematic diagram of the divisions of the sulcus and the types of spatial distribution of abnormal findings on MR imaging. Schematic diagram of the divisions of the sulcus and the types of spatial distribution of abnormal findings on MR imaging. A, Line a is tangential to the interior border of the gray matter in the sulcus bottom, and line b is parallel to line a, intersecting the bottom point of the sulcus. Gray matter interior and exterior to line b is defined as the bottom and the nonbottom parts, respectively. If one considered gray-white matter junction blurring, for example, spatial distribution types 1 (B), 2 (C), and 3 (D) are defined as the abnormalities located in the bottom part, both the bottom and nonbottom parts, and the nonbottom part, respectively. Z. Liu et al. AJNR Am J Neuroradiol 2019;40:184-190 ©2019 by American Society of Neuroradiology