scholarly journals Diffusion Tensor Imaging Features of the Auditory Pathways in Patients With Vestibular Schwannoma After Gamma Knife Radiosurgery

Cureus ◽  
2021 ◽  
Author(s):  
Dilek H Cesme ◽  
Alpay Alkan ◽  
Mehmet Ali Gultekin ◽  
Lutfullah Sari ◽  
Gokberk Alkan ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Imaging Features ◽  
Auditory Pathways

scholarly journals Stereotactic diffusion tensor imaging tractography for Gamma Knife radiosurgery

2016 ◽  
Vol 125 (Supplement_1) ◽  
pp. 139-146 ◽  
Author(s):  
Cormac G. Gavin ◽  
H. Ian Sabin
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Stereotactic Radiosurgery ◽  
Treatment Planning ◽  
Vestibular Schwannoma ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Optic Radiation ◽  
Arcuate Fasciculus ◽  
Stereotactic Frame

OBJECTIVEThe integration of modern neuroimaging into treatment planning has increased the therapeutic potential and safety of stereotactic radiosurgery. The authors report their method of integrating stereotactic diffusion tensor imaging (DTI) tractography into conventional treatment planning for Gamma Knife radiosurgery (GKRS). The aim of this study was to demonstrate the feasibility of this technique and to address some of the technical limitations of previously reported techniques.METHODSTwenty patients who underwent GKRS composed the study cohort. They consisted of 1 initial test case (a patient with a vestibular schwannoma), 5 patients with arteriovenous malformations, 9 patients with cerebral metastases, 1 patient with parasagittal meningioma, and 4 patients with vestibular schwannoma. DT images were obtained at the time of standard GKRS protocol MRI (T1 and T2 weighted) for treatment, with the patient's head secured by a Leksell stereotactic frame. All studies were performed using a 1.5-T magnet with a single-channel head coil. DTI was performed with diffusion gradients in 32 directions and coregistered with the volumetric T1-weighted study. DTI postprocessing by means of commercially available software allowed tensor computation and the creation of directionally encoded color–, apparent diffusion coefficient–, and fractional anisotropy–mapped sequences. In addition, the software allowed visualized critical tracts to be exported as a structural volume and integrated into GammaPlan as an “organ at risk” during shot planning. Combined images were transferred to GammaPlan and integrated into treatment planning.RESULTSStereotactic DT images were successfully acquired in all patients, with generation of correct directionally encoded color images. Tract generation with the software was straightforward and reproducible, particularly for axial tracts such as the optic radiation and the arcuate fasciculus. Corticospinal tract visualization was hampered by some artifacts from the base of the stereotactic frame, but this was overcome by a combination of frame/MRI volume adjustment and DTI seeding parameters. Coregistration of the DTI series with the T1-weighted treatment volume at the time of imaging was essential for the generation of correct tensor data. All patients with the exception of the vestibular schwannoma cases had treatment pathology in the vicinity of eloquent tracts and/or the cortex. No new neurological deficits due to radiation were recorded at the short-term follow-up.CONCLUSIONSRecent reports in the medical literature have suggested that white matter tracts (particularly the optic radiation and arcuate fasciculus) are more vulnerable to radiation during stereotactic radiosurgery than previously thought. Integration of stereotactic tractography into GKRS represents a promising tool for preventing GKRS complications by reduction in radiation doses to functional organs at risk, including critical cortical areas and subcortical white matter tracts.

scholarly journals Evaluation of Brainstem Subcortical Auditory Pathways with Diffusion Tensor Imaging After Gamma Knife Radiosurgery in Intracanalicular Vestibular Schwannoma

2021 ◽  
Author(s):  
Dilek Hacer Çeşme ◽  
Alpay Alkan ◽  
Mehmet Ali Gültekin ◽  
Lütfullah Sarı ◽  
Gökberk Alkan ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Tumor Volume ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Response To Treatment ◽  
Auditory Pathways ◽  
Significant Difference ◽  
Before And After ◽  
Adc Values ◽  
The Relationship

Objective: To investigate changes in DTI (Diffusion Tensor Imaging) parameters in brainstem subcortical auditory pathways after Gamma Knife Radiosurgery (GKR) in patients with intracanalicular vestibular schwannoma (ICVS) and to analyze the relationship between tumor volume and ADC (apparent diffusion coefficient) and FA (fractional anisotropy) values. Method: Seventeen patients with ICVS were evaluated before and after GKR. ADC and FA values of the lateral lemniscus (LL) and inferior colliculus (IC) and tumor volume were calculated. Patients who responded to GKR were classified as Group 1 and those who did not respond adequately as Group 2. The relationship between ADC and FA values and changes in tumor volume were analyzed. Results: Tumor volume significantly decreased after GKR. ADC values obtained from the tumor increased after GKR (p: 0.002). There was no significant difference in LL and IC before and after GKR in terms of FA and ADC values (n: 17). There was a positive correlation between response to treatment and contralateral LL ADC values after GKR (p=0.005, r: 0.652). There was a negative correlation between contralateral IC FA values after GKR and response to treatment (p=0.017, r: -0.568). There was a significant difference between Groups 1 and 2 in regards to contralateral LL ADC (p=0.03) and IC FA values (p=0.017). Conclusion: Since the cochlear nerve and subcortical auditory pathways have low regeneration potential after nerve damage, ADC and FA changes in LL and IC may be explained with the presence of intracanalicular tumors prior to GKR. Since GKR does not cause additional damage to the subcortical auditory pathways at the brainstem level, we think that GKR is a noninvasive treatment method that can be used safely in patients with ICVS.

SU-F-J-92: Predictive Value of Diffusion Tensor Imaging Parameters for Gamma Knife Radiosurgery in Meningiomas

2016 ◽  
Vol 43 (6Part10) ◽  
pp. 3427-3428
Author(s):  
H Speckter ◽  
J Bido ◽  
G Hernandez ◽  
L Suazo ◽  
D Rivera ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Gamma Knife ◽  
Predictive Value ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Imaging Parameters

scholarly journals Prognostic value of diffusion tensor imaging parameters for Gamma Knife radiosurgery in meningiomas

2016 ◽  
Vol 125 (Supplement_1) ◽  
pp. 83-88 ◽  
Author(s):  
Herwin Speckter ◽  
Jose Bido ◽  
Giancarlo Hernandez ◽  
Diones Rivera Mejía ◽  
Luis Suazo ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Gamma Knife ◽  
Tumor Size ◽  
Diffusion Tensor ◽  
Fibrous Tissue ◽  
Gamma Knife Radiosurgery ◽  
Mean Diffusivity ◽  
Prescription Dose ◽  
Diffusion Tensor Imaging Dti

OBJECTIVEDiffusion tensor imaging (DTI) parameters are able to differentiate between meningioma subtypes. The hypothesis that there is a correlation between DTI parameters and the change in tumor size after Gamma Knife radiosurgery (GKRS) was analyzed.METHODSDTI parameters were measured using MRI before GKRS in 26 patients with meningiomas. The findings were correlated with the change in tumor size after treatment as measured at the last follow-up (range 12.5–45 months).RESULTSOnly those meningiomas that showed the highest fractional anisotropy (FA), the lowest spherical index of the tensor ellipsoid (Cs), and the lowest radial diffusivity (RD) either increased or remained stable in terms of volume, whereas all other meningiomas decreased in volume. The correlation between the DTI parameters (correlation values of −0.81 for FA, 0.75 for Cs, 0.66 for RD, and 0.66 for mean diffusivity) and the rate of volume change per month was significant (p ≤ 0.001). Other factors, including original tumor size, prescription dose, and patient age, did not correlate significantly.CONCLUSIONSMeningiomas that show high FA values—as well as low Cs, low RD, and low mean diffusivity values—do not respond as well to GKRS in comparison with meningiomas with low FA values. This finding might be due to their higher content level of fibrous tissue. In particular, the meningioma with the highest FA value (0.444) considerably increased in volume (by 32.3% after 37 months), whereas the meningioma with the lowest FA value (0.151) showed the highest rate of reduction (3.3% per month) in this study.

Temporal disconnection between pain relief and trigeminal nerve microstructural changes after Gamma Knife radiosurgery for trigeminal neuralgia

2020 ◽  
Vol 133 (3) ◽  
pp. 727-735
Author(s):  
Peter Shih-Ping Hung ◽  
Sarasa Tohyama ◽  
Jia Y. Zhang ◽  
Mojgan Hodaie
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Pain Intensity ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Time Points ◽  
Microstructural Effect

OBJECTIVEGamma Knife radiosurgery (GKRS) is a noninvasive surgical treatment option for patients with medically refractive classic trigeminal neuralgia (TN). The long-term microstructural consequences of radiosurgery and their association with pain relief remain unclear. To better understand this topic, the authors used diffusion tensor imaging (DTI) to characterize the effects of GKRS on trigeminal nerve microstructure over multiple posttreatment time points.METHODSNinety-two sets of 3-T anatomical and diffusion-weighted MR images from 55 patients with TN treated by GKRS were divided within 6-, 12-, and 24-month posttreatment time points into responder and nonresponder subgroups (≥ 75% and < 75% reduction in posttreatment pain intensity, respectively). Within each subgroup, posttreatment pain intensity was then assessed against pretreatment levels and followed by DTI metric analyses, contrasting treated and contralateral control nerves to identify specific biomarkers of successful pain relief.RESULTSGKRS resulted in successful pain relief that was accompanied by asynchronous reductions in fractional anisotropy (FA), which maximized 24 months after treatment. While GKRS responders demonstrated significantly reduced FA within the radiosurgery target 12 and 24 months posttreatment (p < 0.05 and p < 0.01, respectively), nonresponders had statistically indistinguishable DTI metrics between nerve types at each time point.CONCLUSIONSUltimately, this study serves as the first step toward an improved understanding of the long-term microstructural effect of radiosurgery on TN. Given that FA reductions remained specific to responders and were absent in nonresponders up to 24 months posttreatment, FA changes have the potential of serving as temporally consistent biomarkers of optimal pain relief following radiosurgical treatment for classic TN.

scholarly journals Pontine Tegmental Cap Dysplasia: MR Imaging and Diffusion Tensor Imaging Features of Impaired Axonal Navigation

2008 ◽  
Vol 30 (1) ◽  
pp. 113-119 ◽  
Author(s):  
P. Jissendi-Tchofo ◽  
D. Doherty ◽  
G. McGillivray ◽  
R. Hevner ◽  
D. Shaw ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Mr Imaging ◽  
Diffusion Tensor ◽  
Imaging Features ◽  
And Diffusion

The Effectiveness of Diffusion Tensor Imaging in Determining Radiological Response after Radiosurgery in Patients with Vestibular Schwannoma

2021 ◽  
Vol 17 ◽  
Author(s):  
Dilek Hacer Cesme ◽  
Alpay Alkan ◽  
Lutfullah Sari ◽  
Ahmet Kaya ◽  
Ismail Yurtsever ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Vestibular Schwannoma ◽  
Tumor Volume ◽  
Diffusion Tensor ◽  
Response To Treatment ◽  
Adc Values ◽  
Radiological Response ◽  
Group 2 ◽  
Group 1

Background: The effectiveness of Diffusion Tensor Imaging (DTI) in demonstrating functional changes in the tumor in determining the response to treatment after radiosurgery in patients with vestibular schwannoma (VS) is not clear yet. Objective: The study aimed to determine the change total in tumor volume (TTV) in terms of radiological response in patients who had VS and were treated with radiosurgery and investigate the relationship between the TTV, follow-up times and DTI parameters. Methods: Thirty-one patients were assessed using DTI and MRI. TTV, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated. Patients were divided into tree groups: those who responded to the treatment (group 1) (n=11), who did not (group 0) (n=9) and who remained stable (group 2) (n=11). Background: The effectiveness of Diffusion Tensor Imaging (DTI) in demonstrating functional changes in the tumor in determining the response to treatment after radiosurgery in patients with vestibular schwannoma (VS) is not clear yet. Objective: The study aimed to determine the change total in tumor volume (TTV) in terms of radiological response in patients who had VS and were treated with radiosurgery and investigate the relationship between the TTV, follow-up times and DTI parameters. Methods: Thirty-one patients were assessed using DTI and MRI. TTV, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated. Patients were divided into tree groups: those who responded to the treatment (group 1) (n=11), who did not (group 0) (n=9) and who remained stable (group 2) (n=11). Results: The mean duration of follow-up was 28.81±14 months. ADC values increased in patients with VS after radiosurgery (p=0.004). There was no statistical difference in the FA values. A significant reduction in TTV after radiosurgery was detected in group 1 (p=0.003). ADC values increased significantly after radiosurgery in group 2 (p=0.04). Although there were no significant differences, ADC values after radiosurgery increased in group 1 and group 0. Conclusions: ADC values continuously increase due to radiation damage in the period before the tumor volume shrinks after radiosurgery. We think that it is not appropriate to diagnose inadequate treatment or progression only when TTV is evaluated in terms of response to treatment in the early period after radiosurgery.

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