Magnetic resonance imaging of the cavernous sinus.

The magnetic resonance (MR) appearance of the cavernous sinus (CS) was studied in 10 normal and 23 abnormal CSs(11 vascular and 12 neoplastic lesions) using T1-weighted spin echo images with and without Gd-DTPA. In normal CSs, the intracavernous carotid artery (ICA) was disclosed as an area of signal void that was not enhanced with Gd-DTPA. Most venous flow showed low intensity and was markedly enhanced with Gd-DTPA. Venous flow, however, was heterogeneous, which suggested the distribution of flow velocities. In the carotid-cavernous sinus fistulas (CCFs), the ICA and shunted flow were disclosed as areas of signal void and their relationship was clearly shown. Normal venous flow appeared as a low intensity area even with CCFs. In the cavernous aneurysms, thrombosis and patent arterial flow were shown, but in one case it was impossible to differentiate patent arterial flow from calcification. In neoplastic lesions, CS invasion was suspected by encasement or marked dislocation of the ICA, disappearance of venous flow, and extension of extrasellar tumors to the medial wall and extension of sellar tumors to the lateral wall. MR was found to be a promising diagnostic modality for the evaluation of the CS.