Origin of high signal intensity in the cavernous sinus in MR angiographic source images: correlation between MR and conventional angiography.

OBJECTIVE: To investigate the origin of a high signal intensity in a cavernous sinus on magnetic resonance (MR) angiography.
METHODS: Time-of-flight MR angiography was performed in 20 patients scheduled for conventional angiography for disease not related to carotid cavernous fistula. Venous drainage pattern was assessed, and flow rate to a cavernous sinus was semiquantitatively evaluated on conventional angiography.
RESULTS: Two sinuses showed high signal intensity in the anterior portion. These were associated with direct venous drainage to the anterosuperior aspect of the cavernous sinus from the superficial middle cerebral vein, and their flow rates were among the 10% of the sides with the highest flow rates. Two other sinuses showed high signal intensity in the posterior portion. Their flow rates from the superficial petrosal sinus were also among the 10% of the sides with the highest flow rates.
CONCLUSION: High signal intensity in the anterior or posterior portions of the cavernous sinus is probably a result of inflow from the superficial middle cerebral vein and the superior petrosal sinus, respectively.