"Digital subtraction angiography (DSA) can be used to definitively exclude dural arteriovenous fistula when asymmetric cavernous sinus enhancement is encountered on cross-sectional imaging but should be reserved for cases where symptoms are present or pre-test likelihood of pathology is high. In these cases, DSA will be normal 1."
"cavernous sinus mass (e.g. cavernous sinus schwannoma)"