MR findings of acoustic neurinomas after linear accelerator-based stereotactic radiosurgery (SRS) and correlation with treatment results

Twenty two patients with acoustic neurinomas were treated by linear accelerator-based SRS and had follow-up MR studies. Loss of central contrast enhancement was seen in 19 tumors 3-9 months after SRS, and none of them showed progression. Of the remaining 3 tumors, 2 showed progression. Loss of central enhancement may indicates that there may be further shrinkage of the tumor. Transient increase in volume of acoustic neurinomas after SRS was observed in 9 tumors but it did not necessarily indicate increased risk of hearing loss. (author)