Franca Wagner1, Matteo Gandalini2,3, Arsany Hakim2, Ekin Ermis4, Dominic Leiser4, Martin Zbinden2, Lukas Anschuetz5, Andreas Raabe6, Marco Caversaccio5, Roland Wiest2, Evelyn Herrmann4. 1. Institute for Diagnostic and Interventional Neuroradiology, University Hospital Bern and Inselspital, Freiburgstraße 4, 3010, Bern, Switzerland. franca.wagner@insel.ch. 2. Institute for Diagnostic and Interventional Neuroradiology, University Hospital Bern and Inselspital, Freiburgstraße 4, 3010, Bern, Switzerland. 3. Departments of Radiology, Radiotherapie and Radiology Practice, Konstanz, Germany. 4. Departments of Radiation Oncology, Inselspital, University of Bern, Bern, Switzerland. 5. Departments of Otorhinolaryngology and Head and Neck Surgery, Inselspital, University of Bern, Bern, Switzerland. 6. Departments of Neurosurgery, Inselspital, University of Bern, Bern, Switzerland.
Abstract
PURPOSE: Stereotactic radiosurgery (SRS) is an effective treatment for vestibular schwannoma (VS). Three-dimensional (3D) constructive interference in steady state (CISS) is the preferred magnetic resonance imaging (MRI) sequence for evaluating signal changes in the inner ear endolymph. Previous studies demonstrated a correlation between pretreatment cochlear signal intensity in 3D-CISS and posttherapeutic hearing outcomes. The purpose of our study was to compare 3D-CISS sequences before and after primary SRS of unilateral VSs to evaluate the effect of radiosurgery on the 3D-CISS signal intensities of cochlea and sacculus/utriculus. METHODS: We retrospectively reviewed 47 patients with unilateral VS treated with SRS. The neuroradiological MRI datasets were analysed to evaluate the signal intensity of the inner ear structure, tumour size, Koos grade, tumour volume, and infiltration of the cochlear aperture before therapy and at follow-up. The differences in these signal intensities before SRS and at follow-up were correlated with clinical symptoms, cochlear radiation dose, tumour volume and infiltration of the cochlear aperture. RESULTS: No differences were found between signal intensities in cochlea and utriculus/sacculus before and after SRS and no correlation with clinical symptoms, cochlear radiation dose, tumour volume, Koos grade or infiltration of the cochlear aperture (all p > 0.05). CONCLUSION: Our study supports the theory of a complex interaction causing alteration of the endolymph protein concentration and not a direct dependency on the SRS. Use of modern dosing schemes will have a positive impact on clinical outcome with preservation of hearing in patients with VS.
PURPOSE: Stereotactic radiosurgery (SRS) is an effective treatment for vestibular schwannoma (VS). Three-dimensional (3D) constructive interference in steady state (CISS) is the preferred magnetic resonance imaging (MRI) sequence for evaluating signal changes in the inner ear endolymph. Previous studies demonstrated a correlation between pretreatment cochlear signal intensity in 3D-CISS and posttherapeutic hearing outcomes. The purpose of our study was to compare 3D-CISS sequences before and after primary SRS of unilateral VSs to evaluate the effect of radiosurgery on the 3D-CISS signal intensities of cochlea and sacculus/utriculus. METHODS: We retrospectively reviewed 47 patients with unilateral VS treated with SRS. The neuroradiological MRI datasets were analysed to evaluate the signal intensity of the inner ear structure, tumour size, Koos grade, tumour volume, and infiltration of the cochlear aperture before therapy and at follow-up. The differences in these signal intensities before SRS and at follow-up were correlated with clinical symptoms, cochlear radiation dose, tumour volume and infiltration of the cochlear aperture. RESULTS: No differences were found between signal intensities in cochlea and utriculus/sacculus before and after SRS and no correlation with clinical symptoms, cochlear radiation dose, tumour volume, Koos grade or infiltration of the cochlear aperture (all p > 0.05). CONCLUSION: Our study supports the theory of a complex interaction causing alteration of the endolymph protein concentration and not a direct dependency on the SRS. Use of modern dosing schemes will have a positive impact on clinical outcome with preservation of hearing in patients with VS.
Entities:
Keywords:
3D-CISS; Labyrinth signal loss; Magnetic resonance imaging; Radiosurgery; Vestibular schwannoma
Authors: May N Tsao; Arjun Sahgal; Wei Xu; Antonio De Salles; Motohiro Hayashi; Marc Levivier; Lijun Ma; Roberto Martinez; Jean Régis; Sam Ryu; Ben J Slotman; Ian Paddick Journal: J Radiosurg SBRT Date: 2017