<prompt> Delta sign on CT is seen in?Gradenigo syndromeSubdural hematomaExtradural hematomaSagittal sinus thrombosis  <response>: Ans. is d i.e., Sagittal sinus thrombosis The delta sign or empty delta sign is CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect. 