Delta-sign is seen in -

Ans. is 'c' i.e., Sigmoid sinus thrombosiso 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.o Delta-sign may also be seen on contrast enhanced MRI.Lateral sinus thrombosis (sigmoid sinus thrombosis)o Lateral or sigmoid sinus thrombophlebitis arises from inflammation in the adjacent mastoid. It may occur as a complication of: -Acute coalescent mastoiditisCSOM and cholesteatomaClinical featureso Hectic Picket-Fence type of fever with rigor.o Headache, Progressive anemia and emaciation.o Griesinger's sign :- odema over the posterior part of mastoid due to thrombosis of mastoid emissary veins. o Papilloedemao Tobey-Ayer test:- Compression of vein on the thrombosed side produces no effect while compression of vein on healthy side produces rapid rise in CSF pressure which will be equal to bilateral compression of jugular veins.o Crowe-Beck test:- Pressure on jugular vein of healthy side produces engorgement of retinal veins. Pressure on affected side does not produce such change.o Tenderness along jugular veinImaging studieso 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.o Delta-sign may also be seen on contrast enhanced MRI.