Magnetic resonance imaging of dural venous sinus invasion, occlusion and thrombosis.

Seventeen patients were found to have involvement of the dural venous sinuses on magnetic resonance imaging (MRI). In 7, there was tumor invasion through the dural coverings and in 10 thrombosis occurred as a result of various causes. MRI shows tumor in the sinus as a signal producing mass replacing the normal hypointensity of rapidly flowing blood. Disruption of the hypointense leaves of the enveloping dura is also well shown by MRI. Intravascular clotting, whether in the chemical state of deoxyhemoglobin or intra- or extracellular methemoglobin can be characterized by MRI operating at high field (1.5 tesla). MRI is now the non-invasive diagnostic modality of choice in evaluation of the dural venous sinuses.