Establishing a pre-operative diagnosis of lateral sinus thrombosis can be difficult, as the clinical features are non-specific and laboratory tests unhelpful. CT maydemonstrate abnormal high density of the lumen of the sinus, which does not enhance afterintravenous contrast medium. Enhancement of the dura surrounding the sinus may be prominent, causing the ‘empty triangle’ or ‘delta sign’ which may suggest the diagnosis. Magnetic resonance (MR) imaging may show both lack of flow and abnormal signal from the sinus, thus providing definitive evidence of thrombosis.
