Figure 4.

Summary of radiological criteria of cavernous sinus (CS) extension of sellar tumors. (a) Hirsch et al. [93] suggested three grades to define encasement of the parasellar ICA for tumors invading the CS: in grade 1, the tumor partially touches the ICA; in grade 2, the ICA is encircled without luminal narrowing, and in grade 3 the ICA diameter reduction is evident. This staging system is not usually used for PAs, but rather for all lesions found in the parasellar region [106,107,108]. Cavernous ICA stenosis is rarely found in PAs. (b) Moreau and coworkers [71,72] defined three criteria to investigate CS invasion, based on intercarotid lines, the subdivision of the cavernous ICA in quadrants, and analysis of the angle defined by the ICA surface in contact with the PA.