label: Empty delta sign
label_lc: empty delta sign
description: "This sign is created by a nonenhancing thrombus in the dural sinus surrounded by triangular enhancing dura as seen on cross-section. The sign, seen on contrast-enhanced CT scan images, suggests dural sinovenous thrombosis. It is best seen on wider window settings. It is a reliable sign of sinus thrombosis but is seen only in 25-30% of these cases."