Technical note: Enhanced radiosurgical planning for cavernous sinus tumors using T1 SPACE sequences with...

Area of Science:

• Neurosurgery
• Radiology
• Oncology

Background:

• Cavernous sinus tumors (CST) are treatable with radiosurgery, but proximity to the optic nerve poses risks.
• Delineating the internal carotid artery adjacent to the distal dural ring (ICAddr) is challenging, increasing potential optic toxicity from radiation over-contouring.

Purpose of the Study:

• To evaluate the efficacy and safety of a 3D T1-weighted Turbo Spin-Echo (TSE) MR sequence with Motion-Sensitized Driven Equilibrium (MSDE) for ICAddl delineation in CST radiosurgery.
• To minimize radiation-induced optic toxicity by improving target volume accuracy.

Main Methods:

• Nine patients with CST underwent Gamma Knife radiosurgery between 2021-2023.
• A 3D T1-weighted TSE MR sequence with MSDE was utilized for improved ICAddl visualization.
• Precise dosimetry near the optic nerve was facilitated by enhanced delineation.

Main Results:

• All patients achieved stable disease at a median 15-month follow-up; no tumor progression was reported.
• The T1-weighted TSE MR sequence with MSDE significantly improved ICAddl delineation from CST.
• One patient had transient diplopia; no other visual deficits occurred.

Conclusions:

• The T1 SPACE sequence enhances radiosurgical planning for CST by enabling precise contouring near the ICAddl and optic nerve.
• This technique reduces radiation dose to the ipsilateral optic nerve.
• Integrating this method into standard practice can significantly benefit CST radiosurgical management.