Delta-sign is seen in-

(Refer: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 92) Contrast-enhanced CT scan can show sinus thrombosis by typical delta-sign.  It is a triangular area with rim enhancement, and central low density area is seen in posterior cranial fossa on axial cuts Delta-sign may also be seen on contrast enhanced MRI