Finding the calcarine should not be hard for the user on the t1. The group b patient is the same as the group a patient presented in a. The optic radiation contains tracts which transmit visual information from the retina of the eye to the visual cortex. Knowing the exact location of the optic radiation preoperatively is important for surgery of the temporal lobe. Optic radiation definition of optic radiation by medical. We use diffusion tensor imaging and fiber tractography dtift to identify the most likely. A reliability and agreement assessment of the tractography method joseph yuanmou yang 1,2,3,4, richard beare 2,5, michelle hao wu 6, sarah m. Strengths and limitations of tractography methods to. Workup revealed a mass in the atrium of the left lateral ventricle consistent with a meningioma. Aug 31, 2016 tractography of the optic chiasm showed that the number of fibers in the affected optic radiation was less than that in the contralateral unaffected optic radiation in patients with ms. This exposure can result in negative health effects. Probabilistic mri tractography of the optic radiation using. Preoperative diffusiontensor tractography showed that the optic radiation was deviated superiorly and medially relative to the mass lesion. Anatomical constraints improve tractography of the optic radiation in ms.
Probabilistic tractography is more accurate but timeconsuming. Optic radiation tractography is represented in green, and imaging methods are the same as explained in a. Optic radiation fiber tractography in glioma patients. To test this hypothesis, this study evaluated differences in dt fiber tractography of the. Stereotactic diffusion tensor imaging tractography for gamma. Nilsson1,2 1department of clinical neuroscience and rehabilitation, institute of neuroscience and physiology, the sahlgrenska academy, university of.
The right preoperative optic radiation is overlaid onto the preoperative sagittal nondiffusionweighted images left and postoperative images right. White matter tractspecific quantitative analysis in multiple. An alternative and simple technique for the accurate detection of meyers loop. Figure 2 shows the reconstructed tracts, including the prechiasmatic portion of the optic nerve, as well as the chiasm and the optic tract, up to the optic radiation and lateral geniculate body lgb. Identifying the human optic radiation using diffusion. In addition to analyzing its shape, we counted the number of fibers in the optic radiation for both cerebral hemispheres by a function of dtistudio software, and any. Improved framework for tractography reconstruction of the optic. We hypothesized that a greater number of motionprobing gradients mpgs would provide better results of diffusion tensor dt fiber tractography of the optic radiation. Diffusion tensor imaging of occult injury of optic radiation. The tractography derived preoperative optic radiation overlies the resected anterior temporal lobe right, particularly in its anterior part ie, the anterior border of the meyers loop. Realtime tractography of the optic radiation youtube. Thus propagation of preoperative probabilistic tractography of the optic radiation to. Act, a modular addition to the tractography software package mrtrix3, to accurately.
Diffusion tensor fiber tractography for arteriovenous. Optimization of tractography of the optic radiations. Yamamoto a, miki y, urayama s, fushimi y, okada t, hanakawa t, et al. Progressive injury in chronic multiple sclerosis lesions is. The human optic radiation or is the main pathway for conveying visual. Tractography reconstructions of the or have proven useful beyond providing an. A lack of standardization of tg of the optic radiation makes study.
To test this hypothesis, this study evaluated differences in dt fiber tractography. Identifying the human optic radiation using diffusion imaging and. Anatomically constrained tractography facilitates biologically. Methods image acquisition srr was acquired on one healthy male, aged 23 years and two healthy females, aged 21 years. Tractography algorithms are then used to trace white matter pathways by following the predominant direction of diffusion. The dmri data were used to reconstruct the optic radiation with probabilistic constrained spherical deconvolution. We present a case of intraventricular meningioma resected via a transcortical approach using tractography for optic radiation and arcuate fasciculus preservation. The optic radiation or is a white matter bundle with a very complex anatomy. Surgical strategy of brain tumors adjacent to the optic. We evaluated the accuracy of each technique measuring 3 distances that. Strengths and limitations of tractography methods to identify the optic radiation for epilepsy surgery ylva lilja1, daniel t. Probabilistic tractography of the optic radiationsan. Commercial software performs only rigid registration between images so cannot account for the brain shift during surgery, which may be up to 11mm in the optic radiation5.
Tractography may assist surgical planning by suggesting the optimum approach to a lesion and indicating the proximity of the lesion to the optic radiation. In contrast, in fsl fmrib software library the principal diffusion or fiber directions. Diffusion tensor fiber tractography of the optic radiation. Frontiers optic radiation tractography in pediatric brain. 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. Giulio a bertani unit of neurosurgery, fondazione irccs ca granda ospedale maggiore policlinico, milan, italy. The probability of not being in the optic radiation was taken as 1 minus the probability of being in the optic radiation. Bertani 1 lorenzo bertulli 1 elisa scola 2 andrea di cristofori 1 mario zavanone 1 fabio triulzi 2 paolo m. Resultstwelve patients 60% suffered a vfd 1092% of upper quadrant. The optic radiation or is one of the major components of the visual. The optic radiation or is the primary visual white matter tract wmt in the human brain, connecting the. The optic radiation receives blood through deep branches of the middle cerebral artery and posterior cerebral artery.
All the custom image processing software is available as part of our. Bauer, 1, 2, 5 jens sommer, 3 dorit merhof, 4 and christopher nimsky 1. For example, one can determine the location of the corticospinal tract or the thalamocortical tract with the help of dti tractography. Eight patients presenting to the childrens epilepsy surgery program at. Retinal ganglion cell topography predicts visual field. Frontiers optic radiation tractography in pediatric. Diffusionbased tractography in neurological disorders. Optic radiation changes after optic neuritis detected by tractography based group mapping. When this is mediotemporally, there is a risk of cutting accidentally the optic fibers, which could partially blind the patient. Strengths and limitations of tractography methods to identify the. Optic radiation or tractography may help predict and.
Optic radiation injury in patients with aneurismal. The optic radiation or is the primary visual white matter tract wmt in the human brain, connecting the lateral geniculate body lgb of the thalamus to the primary visual cortex in the occipital lobe ebeling and reulen, 1988. Simple voiceover tutorial on how to use the realtime fiber tractography module of the fibernavigator. Diffusion tensor imaging tractography of the optic radiation. Damage to the optic radiation in multiple sclerosis is. A reliability and agreement assessment of the tractography method introduction. Analysis with 6, 12, 40, and 81directional motionprobing gradients, a preliminary study. Optic radiation tractography and vision in anterior. Reconstruction result of the optic radiation using probabilistic tractography. We evaluated the accuracy of each technique measuring 3 distances that define. Tract generation with the software was straightforward and reproducible, particularly for axial tracts such as the optic radiation and the arcuate fasciculus. Diffusion tensor imaging, epilepsy surgery, optic radiation, tumours. Diffusion tensor imaging tractography of the optic radiation for epilepsy surgical planning. A, dtibased tractography showing the optic radiation below the cortical dysplasia.
Functional monitoring for visual pathway using realtime. Preservation of the optic radiations based on comparative analysis of diffusion tensor imaging tractography and anatomical dissection. Patients were classified into 1 of 3 groups based on the distance between avm nidus and tract and the presence of visual field defect. The anteroposterior extent of the damage to meyers loop was determined, and visual loss was quantified using goldmann perimetry. Propagation of probabilistic tractography of the optic. The patient underwent a left occipital craniotomy, and gross total resection of the mass lesion was performed using the transcortical lingual gyrus approach figs. Each of the steps taken was chosen with reference to the overall.
No definitive method of preventing visual field deficits after stereotactic radiosurgery for lesions near the optic radiation or has been available so far. Tractography of the optic radiation with diffusion. Cureus tractography for optic radiation preservation in. They carry visual information through two divisions to the visual cortex along the calcarine fissure. Optic radiation tractography and vision in anterior temporal lobe resection. We evaluated the accuracy of each technique measuring 3 distances that define the ml position. Corticospinal tract visualization was hampered by some artifacts from the base of the stereotactic frame, but this was overcome by a combination of framemri volume adjustment and dti. Tractography of the optic radiation can be used preoperatively to determine the distance between the temporal pole and meyers loop.
An alternative and simple technique for the accurate detection of meyers loop author links open overlay panel giulio a. We created 5 data groups and compared the 2 techniques. We have developed an alternative tracking technique to detect the ml position. Finally, we compared our results with the results from 8 anatomic dissection studies. Across the group the most anterior extent of the radiations fell on average 0. Winston, a, 1 laura mancini, b, c, 1 jason stretton, a jonathan ashmore, b mark r. While software efficiency cannot be ruled out, we believe that the main differences in computation time are due to the different approaches taken. The inputs of the pipeline are a diffusionweighted imaging dwi dataset and an anatomical t1. Dti diffusion tensor imaging tractography uses diffusion tensor data and allows 3d visualization of specific white matter tracts. All mr images were acquired using a 3t siemens trio scanner munich, germany. B diffusion tensor tractography images of the optic radiation in the patient red color. Tractography of the optic nerve included segments spanning the prechiasmatic portion, chiasm, retrochiasmatic tract, and optic radiation. The optic radiation are axons from the neurons in the lateral geniculate nucleus to the primary visual cortex.
Optic radiation fiber tractography in glioma patients based. Optic radiation fiber tractography in glioma patients based on high angular resolution diffusion imaging with compressed sensing compared with diffusion tensor imaging initial experience daniela kuhnt, 1, miriam h. Extrastriate projections in human optic radiation revealed by fmri. Identifying the human optic radiation using diffusion imaging. A 54yearold woman with a history of breast cancer presented with gait imbalance. Strengths and limitations of tractography methods to identify. Strengths and limitations of tractography methods to identify the optic radiation for epilepsy surgery diffusion tensor imaging dti tractography tg can visualize meyers loop ml, providing important information for the epilepsy surgery team, both for preoperative counseling and to reduce the frequency of visual field defects after.
Tractography of the optic radiation was performed on preoperative images and propagated onto postoperative images. Identifying the human optic radiation using diffusion imaging and fiber tractography article pdf available in journal of vision 810. Winston gp, daga p, stretton j, modat m, symms mr, mcevoy aw, et al. May 30, 2018 optic radiation diffusion tensor imaging tractography. For example, identifying the meyers loop portion of the optic radiation or has. Optic radiation tractography and vision in anterior temporal. In vivo visualization of cranial nerve pathways in humans.
If a lesion only exists in one optic radiation, the consequence is called quadrantanopia, which implies that only the. The optic radiation or geniculocalcarine tract is part of the visual pathway, forming the connection between the lateral geniculate nucleus of the pulvinar of the thalamus with the primary visual cortex of the occipital lobe. We might want to do some initial tractography from the chiasm to find the lgn if its difficult to locate on the t1. B, tracings showing intraoperative monitoring of the veps, demonstrating negative deflections peaking at 125 milliseconds with consistent amplitudes during resection.
Simon harvey 3,4,7, vicki anderson 4,9,11,12, wirginia j. Lesions of the optic radiations are usually unilateral and commonly vascular in origin. The diffusion weighted imaging acquisitions were performed as described in scherrer. Bertani ga1, bertulli l 2, scola e3, di cristofori a1, zavanone m1, triulzi f3, rampini pm1, carrabba gg1. Tractography is a complex and timeconsuming process with results that depend upon the method employed. This will be done using itkgray and the anatomical image. Diffusion tensor imaging tractography to visualize the. Optic radiation tractography in pediatric brain surgery applications. C diffusion tensor tractography images of the optic radiation in a normal control male aged 52 years. Because tracts were allowed by the tractography software to extend one voxel into the termination mask before termination, the termination mask was eroded by one voxel before calculating the search volume. Field defects therefore develop abruptly, in contrast to the slow progression of defects associated with tumors. Directionally encoded color maps of optic radiation via a diffusion tensor imaging and b diffusion tensor tractography in a patient with multiple. Optical radiation may be produced by artificial sources, such as uv lights, common lightbulbs, and radiant heaters, but the primary source of exposure for most people is the sun.
Methods the optic radiation or was identified in sixty rrms patients using probabilistic tractography. Optic radiation tractography integrated into simulated. In this example, we quickly extract the highly studied optic radiation using hcp data. In patient 1, preoperative tractography identified the optic radiation passing just inferomedial to the left parietal fcd fig. Anatomically constrained tractography facilitates biologically plausible fiber reconstruction of the optic radiation in multiple sclerosis. Optic radiation diffusion tensor imaging tractography. Streamline tractography is a diffusion magnetic resonance imaging mri postprocessing technique that can generate connections closely following in. Stability metrics for optic radiation tractography.
This strategy yielded tractography results that bore a close correspondence to the known structure of the optic radiations figure 8, table 2. Nov 04, 2015 simple voiceover tutorial on how to use the realtime fiber tractography module of the fibernavigator. Optic radiation tractography in pediatric brain surgery. Objective to evaluate the longitudinal integrity of white matter tracts in patients with relapsing remitting multiple sclerosis rrms as determined by changes in diffusivity indices of lesional and nonlesional white matter in the optic radiation over 12 months. Apr 06, 20 sometimes an epileptic focus has to be removed surgically. Diffusion tensor imaging tractography of the optic radiation for.
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