RT Journal Article
SR Electronic
T1 Peritumoral Hyperintense Signal on Post-contrast FLAIR Images Surrounding Vestibular Schwannomas Following Stereotactic Radiosurgery
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP ajnr.A8657
DO 10.3174/ajnr.A8657
A1 Nguyen, Sandy T.
A1 Benson, John C.
A1 Bathla, Girish
A1 Farnsworth, Paul J.
A1 Carlson, Matthew L.
A1 Link, Michael J.
A1 Lane, John I.
YR 2025
UL http://www.ajnr.org/content/early/2025/01/13/ajnr.A8657.abstract
AB BACKGROUND AND PURPOSE: Prior investigations have noted the presence of peritumoral hyperintense signal (a “halo”) around vestibular schwannomas on postcontrast 3D T2 FLAIR images. This study evaluated this phenomenon in a cohort of patients undergoing stereotactic radiosurgery.MATERIALS AND METHODS: A retrospective review was completed of consecutive patients with presumed vestibular schwannomas undergoing stereotactic radiosurgery. Tumor size, location, presence or absence of a peritumoral halo, and halo thickness were recorded. Images were reviewed for presence and size of peritumoral hyperintense signal on postcontrast 3D T2 FLAIR images before and after treatment.RESULTS: Twenty-six patients were included in this study, 14 of which were female (54.0%). Average age was 62±12 years. Prior to treatment, a post-contrast 3D T2 FLAIR hyperintense peritumoral halo was seen in 85% of patients, averaging 0.8±0.4 mm in thickness. There was a higher incidence of peritumoral halo in post treatment patients (96%) than pre-treatment patients (85%) (p=0.017) with a mean follow up period of 1.2 years (SD, 0.35) from 11/12/2019 to 9/5/2023. The average halo thickness was also larger in posttreatment patients (average=1.4±0.4 mm) compared to pre-treatment patients (0.8±0.4 mm) (p<0.001). Average tumoral size did not significantly change following treatment (p=0.10).CONCLUSIONS: Vestibular schwannomas treated with stereotactic radiosurgery are more likely to have a peritumoral halo on post-contrast 3D T2 FLAIR images, with larger halo size as compared to pre-treatment studies. Further study with a larger tumor cohort and longer follow-up will be necessary to determine if these findings are predictive of subsequent tumor shrinkage.ABBREVIATIONS: VSs = vestibular schwannomas; SRS = stereotactic radiosurgery; CPA = cerebellopontine angle; IAC = internal auditory canal.