Early magnetic resonance image volumetric changes of vestibular schwannoma after Gamma Knife radiosurgery: a prospective study of 18 cases

Egyptian Journal of Neurosurgery

Alhasan Abdul Rahim Taresh¹  Moneer K. Faraj¹  Anwer N. Hafidh² 

[1] Gamma Knife Center, Neurosciences Hospital, Baghdad, Iraq;Neurosurgery/Iraq College of Medicine, Baghdad University, Baghdad, Iraq

关键词: MRI volumetric changes;    Vestibular schwannomas;    Gamma Knife;   

DOI  :  10.1186/s41984-018-0009-4

学科分类：神经科学

来源: Springer

【 摘 要 】

Gamma Knife radiosurgery is the principal alternative to microsurgical resection for acoustic neuromas (vestibular schwannomas). However; its increasing use worldwide and evolution of Gamma Knife device precision and safety had led to its acceptance as primary management for small- and medium-sized vestibular schwannomas. We tried to evaluate the tumor volume changes that occur with these tumors following Gamma Knife radiosurgery. Eighteen patients with stereotactic radiosurgery with Gamma Knife through the year 2016 completed 1-year MRI follow-up at the 3rd, 6th, and 12th month after the Gamma Knife treatment. All the patients had unilateral vestibular schwannomas; the mean dose of radiation to the tumors was 12 Gy (range 10–14 Gy). Post treatment imaging was done with a high-resolution 3 T MRI scanner. Tumor sizes are calculated by using Onis software. Four patterns of volumetric changes were noticed. Most of the tumors increased in size on the third month follow-up MRI (89%); 15 (83%) tumors on the sixth month returned to their initial pre-Gamma Knife radiosurgery (PGKR) sizes. On the last (12th month) follow-up MRI with tumor sizes compared to initial PGKR sizes, 8 (44%) tumors showed no change, 6 (33%) tumors became smaller, and 4 (22%) tumors increase in size. Tumor control rate was 78% for the first year after Gamma Knife radiosurgery. The third month follow-up MR images are practically not informative and might lead to unnecessary intervention; sixth month follow-up MR images are a crucial point and they may predict tumor behavior. Age, gender, and Koos stage whether stage II or III are not affecting tumor control. Gamma Knife radiosurgery is an effective intervention for Koos II and Koos III vestibular schwannomas.

【 授权许可】

CC BY