Optic radiation tractography integrated into simulated treatment planning for Gamma Knife surgery

2007 ◽  
Vol 107 (4) ◽  
pp. 721-726 ◽  
Author(s):  
Keisuke Maruyama ◽  
Kyousuke Kamada ◽  
Masahiro Shin ◽  
Daisuke Itoh ◽  
Yoshitaka Masutani ◽  
...  
Keyword(s):  
Visual Field ◽  
Treatment Planning ◽  
Gamma Knife ◽  
Diffusion Tensor ◽  
Maximum Dose ◽  
Gamma Knife Surgery ◽  
Optic Radiation ◽  
Imaging Studies ◽  
Visual Field Deficits ◽  
Neurological Change

Object No definitive method of preventing visual field deficits after stereotactic radiosurgery for lesions near the optic radiation (OR) has been available so far. The authors report the results of integrating OR tractography based on diffusion tensor (DT) magnetic resonance imaging into simulated treatment planning for Gamma Knife surgery (GKS). Methods Data from imaging studies performed in 10 patients who underwent GKS for treatment of arteriovenous malformations (AVMs) located adjacent to the OR were used for the simulated treatment planning. Diffusion tensor images performed without the patient's head being secured by a stereotactic frame were used for DT tractography, and the OR was visualized by means of software developed by the authors. Data from stereotactic 3D imaging studies performed after frame fixation were coregistered with the data from DT tractography. The combined images were transferred to a GKS treatment-planning workstation. Delivered doses and distances between the treated lesions and the OR were analyzed and correlated with posttreatment neurological changes. Results In patients presenting with migraine with visual aura or occipital lobe epilepsy, the OR was located within 11 mm from AVMs. In a patient who developed new quadrantanopia after GKS, the OR had received 32 Gy. A maximum dose to the OR of less than 12 Gy did not cause new visual field deficits. A maximum dose to the OR of 8 Gy or more was significantly related to neurological change (p < 0.05), including visual field deficits and development or improvement of migraine. Conclusions Integration of OR tractography into GKS represents a promising tool for preventing GKS-induced visual disturbances and headaches. Single-session irradiation at a dose of 8 Gy or more was associated with neurological change.

Integration of three-dimensional corticospinal tractography into treatment planning for gamma knife surgery

2005 ◽  
Vol 102 (4) ◽  
pp. 673-677 ◽  
Author(s):  
Keisuke Maruyama ◽  
Kyousuke Kamada ◽  
Masahiro Shin ◽  
Daisuke Itoh ◽  
Shigeki Aoki ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Gamma Knife ◽  
Diffusion Tensor ◽  
Three Dimensional ◽  
Spatial Relationship ◽  
Gamma Knife Surgery ◽  
Univariate Logistic Regression Analysis ◽  
Content Type ◽  
Combined Images ◽  
Fine Print

Object. In the radiosurgical treatment of critically located lesions, the effort to minimize the risk of complication is essential. In this study the integration of diffusion-tensor (DT) imaging—based tractography was clinically applied to treatment planning for gamma knife surgery (GKS). Methods. Seven patients with cerebral arteriovenous malformations located adjacent to the corticospinal tract (CST) underwent this technique. Data provided by DT imaging were acquired before the frame was affixed to the patient's head and the CST of the DT tractography was created using our original software. Stereotactic three-dimensional imaging studies were obtained after frame fixation and then coregistered with the data from DT tractography. After image fusion of the two studies, the combined images were transported to a GKS treatment-planning workstation. The spatial relationship between the dose distribution and the CST was clearly demonstrated within the 2 hours it took to complete the entire imaging process. The univariate logistic regression analysis of transient or permanent motor complications revealed a significant independent correlation with the volume of the CST that received 25 Gy or more and with a maximum dose to the CST (p < 0.05). Conclusions. The integration of DT tractography into the GKS treatment planning was highly useful in confirming the dose to the CST during treatment planning.

Arcuate fasciculus tractography integrated into Gamma Knife surgery

2009 ◽  
Vol 111 (3) ◽  
pp. 520-526 ◽  
Author(s):  
Keisuke Maruyama ◽  
Tomoyuki Koga ◽  
Kyousuke Kamada ◽  
Takahiro Ota ◽  
Daisuke Itoh ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Treatment Planning ◽  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Diffusion Tensor ◽  
Gamma Knife Surgery ◽  
Arcuate Fasciculus ◽  
Motor Aphasia ◽  
Diffusion Tensor Images ◽  
Temporal Language

Object To prevent speech disturbances after Gamma Knife surgery (GKS), the authors integrated arcuate fasciculus (AF) tractography based on diffusion tensor (DT) MR imaging into treatment planning for GKS. Methods Arcuate fasciculus tractography was retrospectively integrated into planning that had been previously performed by neurosurgeons and radiation oncologists. This technique was retrospectively applied to 12 patients with arteriovenous malformations adjacent to the AF. Diffusion tensor images were acquired before the frame was affixed to the patient's head and DT tractography images of the AF were created using the authors' original software. The data from DT tractography and stereotactic 3D imaging studies obtained after frame fixation were transported to a treatment planning workstation for GKS and coregistered so that the delivered doses and incidence of posttreatment aphasia could be assessed. Results The AF could not be depicted in 2 patients who initially presented with motor aphasia caused by hemorrhaging from arteriovenous malformations. During the median follow-up period of 29 months after GKS, aphasia developed in 2 patients: 30 Gy delivered to the frontal portion of the AF caused conduction aphasia in 1 patient, and 9.6 Gy to the temporal portion led to motor aphasia in the other. Speech dysfunction was not observed after a maximum radiation dose of 10.0–16.8 Gy was delivered to the frontal fibers in 4 patients, and 3.6–5.2 Gy to the temporal fibers in 3. Conclusions The authors found that administration of a 10-Gy radiation dose during GKS was tolerated in the frontal but not the temporal fibers of the AF. The authors recommend confirmation of the dose by integration of AF tractography with GKS, especially in lesions located near the temporal language fibers.

A simple treatment planning strategy for patients with multiple metastases treated with Gamma Knife surgery

2006 ◽  
Vol 105 (Supplement) ◽  
pp. 2-4 ◽  
Author(s):  
James G. Douglas ◽  
Robert Goodkin
Keyword(s):  
Mr Imaging ◽  
Treatment Planning ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Planning Method ◽  
Cns Metastases ◽  
Cell Lung Carcinoma ◽  
Dose Volume Histograms ◽  
Number Of Patients ◽  
The Brain

ObjectIn a substantial number of patients treated at the authors' facility for brain metastases, additional lesions are identified at the time of Gamma Knife surgery (GKS). These lesions are often widely dispersed and may number over 10, which is the maximal number of matrices that can be currently placed for treatment with Leksell Gamma-Plan 4C. The authors describe a simple planning method for GKS in patients with multiple, widely dispersed central nervous system (CNS) metastases.MethodsTwo patients presented with three to five identified recurrent metastases from non–small cell lung carcinoma and breast carcinoma after having received whole-brain radiotherapy. At the time of treatment with GKS in each patient, spoiled-gradient Gd-enhanced magnetic resonance (MR) imaging revealed substantially more metastases than originally thought, which were widely scattered throughout all regions of the brain. The authors simplified the treatment planning approach by dividing the entire CNS contents into six contiguous, nonoverlapping matrices, which allowed for the planning, calculation, and treatment of all lesions.Two patients were successfully treated with GKS for more than 10 CNS metastases by using this simple planning method. Differing peripheral doses to varied-size lesions were delivered by prescribing to different isodose curves within any given matrix when required. Dose–volume histograms showed brain doses as follows: 10% of the total brain volume received 5 to 6.4 Gy; 25% received 3.8 to 4.8 Gy; 50% received 2.7 to 3.1 Gy; and 75% received 2.2 to 2.5 Gy.Conclusions The delineation of more metastases than appreciated on the diagnostic MR imaging is a common occurrence at the time of GKS at the authors' institution. The treatment of multiple (>10), widely dispersed CNS metastases can be simplified by the placement of multiple, contiguous, non-overlapping matrices, which can be employed to treat lesions in all areas of the brain when separate matrices cannot be utilized.

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 Defining Meyer's loop-temporal lobe resections, visual field deficits and diffusion tensor tractography

Brain ◽  
2009 ◽  
Vol 132 (6) ◽  
pp. 1656-1668 ◽  
Author(s):  
M. Yogarajah ◽  
N. K. Focke ◽  
S. Bonelli ◽  
M. Cercignani ◽  
J. Acheson ◽  
...  
Keyword(s):  
Visual Field ◽  
Temporal Lobe ◽  
Diffusion Tensor ◽  
Diffusion Tensor Tractography ◽  
Visual Field Deficits ◽  
Meyer’S Loop ◽  
And Diffusion

scholarly journals The role of diffusion tensor imaging tractography for Gamma Knife thalamotomy planning

2016 ◽  
Vol 125 (Supplement_1) ◽  
pp. 129-138 ◽  
Author(s):  
João Gabriel Ribeiro Gomes ◽  
Alessandra Augusta Gorgulho ◽  
Amanda de Oliveira López ◽  
Crystian Wilian Chagas Saraiva ◽  
Lucas Petri Damiani ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Gamma Knife ◽  
Treatment Time ◽  
Diffusion Tensor ◽  
Pyramidal Tract ◽  
Planning System ◽  
Treatment Planning System ◽  
Motor Complications ◽  
Clinical Series

OBJECTIVEThe role of tractography in Gamma Knife thalamotomy (GK-T) planning is still unclear. Pyramidal tractography might reduce the risk of radiation injury to the pyramidal tract and reduce motor complications.METHODSIn this study, the ventralis intermedius nucleus (VIM) targets of 20 patients were bilaterally defined using Iplannet Stereotaxy Software, according to the anterior commissure–posterior commissure (AC-PC) line and considering the localization of the pyramidal tract. The 40 targets and tractography were transferred as objects to the GammaPlan Treatment Planning System (GP-TPS). New targets were defined, according to the AC-PC line in the functional targets section of the GP-TPS. The target offsets required to maintain the internal capsule (IC) constraint of < 15 Gy were evaluated. In addition, the strategies available in GP-TPS to maintain the minimum conventional VIM target dose at > 100 Gy were determined.RESULTSA difference was observed between the positions of both targets and the doses to the IC. The lateral (x) and the vertical (z) coordinates were adjusted 1.9 mm medially and 1.3 mm cranially, respectively. The targets defined considering the position of the pyramidal tract were more medial and superior, based on the constraint of 15 Gy touching the object representing the IC in the GP-TPS. The best strategy to meet the set constraints was 90° Gamma angle (GA) with automatic shaping of dose distribution; this was followed by 110° GA. The worst GA was 70°. Treatment time was substantially increased by the shaping strategy, approximately doubling delivery time.CONCLUSIONSRoutine use of DTI pyramidal tractography might be important to fine-tune GK-T planning. DTI tractography, as well as anisotropy showing the VIM, promises to improve Gamma Knife functional procedures. They allow for a more objective definition of dose constraints to the IC and targeting. DTI pyramidal tractography introduced into the treatment planning may reduce the incidence of motor complications and improve efficacy. This needs to be validated in a large clinical series.

Initial experience with gamma knife surgery for endocrine ophthalmopathy

2005 ◽  
Vol 102 ◽  
pp. 272-275
Author(s):  
Julio C. Antico ◽  
Luis Crovetto ◽  
Eduardo Tenca ◽  
Carlos Artes
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Resonance Imaging ◽  
Imaging Studies ◽  
Content Type ◽  
Soft Tissue Involvement ◽  
Endocrine Ophthalmopathy ◽  
A Prospective Study ◽  
Fine Print

Object. The aim of this study was to evaluate both the effectiveness and safety of the treatment of endocrine ophthalmopathy with gamma knife surgery (GKS). Methods. Five patients were included in a prospective study designed to assess the results of GKS of endocrine ophthalmopathy secondary to Graves disease. All the patients completed a 2-year follow-up period. During this period, the patients were evaluated both clinically and by means of additional methods, including computerized tomography and magnetic resonance imaging studies. The minimum dose delivered to the 50% isodose line was 6.5 Gy in all the patients. In all cases, a clinical improvement was observed. The best effect was seen in symptom regression related to soft-tissue involvement. No treatment-related side effects were detected. Conclusions. In light of the results obtained the authors consider that GKS may be a safe and effective way to treat endocrine ophthalmopathy.

Prediction of visual field deficits by diffusion tensor imaging in temporal lobe epilepsy surgery

NeuroImage ◽  
2009 ◽  
Vol 45 (2) ◽  
pp. 286-297 ◽  
Author(s):  
Xiaolei Chen ◽  
Daniel Weigel ◽  
Oliver Ganslandt ◽  
Michael Buchfelder ◽  
Christopher Nimsky
Keyword(s):  
Diffusion Tensor Imaging ◽  
Visual Field ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epilepsy Surgery ◽  
Diffusion Tensor ◽  
Visual Field Deficits
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