Fig. 2. Confusing cases in grading lumbar central canal stenosis. Sagittal T2-weighted image (A) shows no obliteration of the ventral cerebrospinal fluid space at the L3/4 level, indicating that there is no central canal stenosis. However, in the corresponding axial T2-weighted image (B), the ventral cerebrospinal fluid space shows heterogeneous hypointensity, which appears as clumping of the cauda equina. Axial T2-weighted image of a 67-year-old male with epidural lipomatosis (C) showing severe collapse of the dural sac. In addition, on an axial T2-weighted image of a 72-year-old male with synovial cysts (D), the cauda equina appear as a single bundle. Severe dural sac collapse by epidural lipomatosis or synovial cysts (C, D) should be determined as severe central canal stenosis.