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Cameron A. Elliott, Hayden Danyluk, Keith E. Aronyk, Karolyn Au, B. Matt Wheatley, Donald W. Gross, Tejas Sankar and Christian Beaulieu

D eterministic diffusion-tensor imaging (DTI) white matter tractography is commonly used in neurosurgical practice but is largely limited to the preoperative setting. Spatial distortions and image degradation caused by susceptibility artifact encountered when using conventional single-shot DTI (SS-DTI) employing echo-planar imaging (EPI) are significant, particularly when acquired intraoperatively (SS-iDTI) in surgical position with an open cavity. 7 , 27 SS-DTI is prone to susceptibility artifact, particularly in areas of the brain where tissue boundaries (e

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Chiara Negwer, Nico Sollmann, Sebastian Ille, Theresa Hauck, Stefanie Maurer, Jan S. Kirschke, Florian Ringel, Bernhard Meyer and Sandro M. Krieg

more hodotopical perspective, describing the language process as an interaction of corticosubcortical subnetworks, cannot be ignored. 9 , 12 , 14 , 18 , 21 , 35 Diffusion tensor imaging (DTI) fiber tracking (FT), in particular, has become a frequently used technique in modern neurosurgery, both in the clinical routine and for neuroscientific research purposes. DTI FT can be based on either functional data (provided by functional MRI [fMRI], nTMS, and so on) or anatomical landmarks. One of the most reproducible language-related, anatomically based DTI FT protocols

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Aditya Vedantam, Katie M. Stormes, Nisha Gadgil, Stephen F. Kralik, Guillermo Aldave and Sandi K. Lam

-motor function, hypotonia, dysphagia, extraocular movement dysfunction, and neuropsychological changes. These deficits often impair activities of daily living, and previous studies have shown that over 40% of patients have impaired function due to these residual deficits. 6 The introduction of advanced MRI for pediatric brain tumors has allowed us to better study the anatomical substrates for neurological dysfunction after posterior fossa surgery. 14 , 18 Diffusion tensor imaging (DTI) measures the directional diffusion of water molecules along axons, and provides a measure

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Shawna Farquharson, J.-Donald Tournier, Fernando Calamante, Gavin Fabinyi, Michal Schneider-Kolsky, Graeme D. Jackson and Alan Connelly

limitations of the most commonly used tractography method, namely DTI 6 -based tractography, are well described in the technical literature, 39 DTI-based tractography remains the most widely used tractography method in the clinical setting. The current study is designed to systematically investigate the practical limitations of using tensor-based tractography for the purpose of clinical investigation and to determine whether using a method designed to address the problems that affect the tensor model provides an acceptable solution. Diffusion MRI tractography requires 3

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Francesco T. Mangano, Mekibib Altaye, Robert C. McKinstry, Joshua S. Shimony, Stephanie K. Powell, Jannel M. Phillips, Holly Barnard, David D. Limbrick Jr., Scott K. Holland, Blaise V. Jones, Jonathan Dodd, Sarah Simpson, Deanna Mercer, Akila Rajagopal, Sarah Bidwell and Weihong Yuan

of ventricular enlargement and increased ICP in hydrocephalus. 13 , 14 , 17 , 20 , 29 , 33 , 35 Diffusion tensor imaging (DTI) is an advanced MRI technique that uses diffusion properties of water molecules as probes to examine tissue structure, revealing characteristics of its microscopic organization. Anisotropic diffusion properties, as measured by DTI, are strongly influenced by the microstructural components of WM 9 and provide a direct indication of the integrity of these components. Recent neuroimaging studies have shown that DTI can provide imaging

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Fraser Henderson Jr., Kalil G. Abdullah, Ragini Verma and Steven Brem

C linical tractography emerged at the beginning of this century with the discovery that noninvasive MR diffusion imaging can approximate human neuronal pathways in vivo. Yet neurosurgeons today lack a standardized method for acquiring and using reconstructed estimations of white matter tracts in glioma surgery for several reasons: the heterogeneity of user-dependent characteristics; the difficulty in validating the correlation between imaging and function; and the confusing variety of diffusion tensor imaging (DTI) and post-DTI algorithms available at a few

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Anthony C. Wang, George M. Ibrahim, Andrew V. Poliakov, Page I. Wang, Aria Fallah, Gary W. Mathern, Robert T. Buckley, Kelly Collins, Alexander G. Weil, Hillary A. Shurtleff, Molly H. Warner, Francisco A. Perez, Dennis W. Shaw, Jason N. Wright, Russell P. Saneto, Edward J. Novotny, Amy Lee, Samuel R. Browd and Jeffrey G. Ojemann

disruption of interhemispheric inhibitory connections via the corpus callosum, including crossed descending corticospinal tracts. 35 Few researchers have used advanced imaging techniques such as functional MRI (fMRI) or diffusion tensor imaging (DTI) to investigate the preservation of motor function relative to the severe hemiparesis expected in patients about to undergo hemispherectomy. 4 , 5 , 19 , 24 , 26 , 39 In this observational study, we evaluate the laterality of hand motor control using fMRI, as well as corticospinal tract integrity via colored fractional

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Asem Salma

TO THE EDITOR: The article by Mandelli et al. 4 and published recently in your journal has several interesting points (Mandelli ML, Berger MS, Bucci M, et al: Quantifying accuracy and precision of diffusion MR tractography of the corticospinal tract in brain tumors. J Neurosurg 121: 349–358, August 2014). The objective of this study was to test the accuracy of diffusion tensor imaging (DTI) and its reliability to guide real-time safe neurosurgical removal of a brain tumor. For this reason, I believe that this article presents an important contribution

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Benjamin M. Ellingson, Noriko Salamon, Davis C. Woodworth, Hajime Yokota and Langston T. Holly

with moderate and severe myleopathy, whereas patients with asymptomatic stenosis or mild symptomatology may be treated nonoperatively and observed, without continual progression 8 , 26 , 27 , 35 in many cases. Due to the aforementioned limitations of conventional MRI, there is significant interest in the development of noninvasive imaging biomarkers to quantify neurological function of the spinal cord in both operatively and nonoperatively treated patients with advanced cervical spondylosis. Diffusion tensor imaging (DTI), an advanced MR technique sensitive to the

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Katharina Faust and Peter Vajkoczy

the temporal lobe. Of all the white matter tracts within the temporal lobe network, the OR is the largest. 32 Recent technical progress has enabled the visualization of fiber tracts in the living subject through diffusion tensor imaging (DTI). Before that, knowledge of the visual pathway was based mainly on fiber dissection studies in deceased subjects 6 , 15 , 21 and partly on the analysis of postoperative visual field deficits. 9 , 13–28 The underlying physics of the DTI technique have been described well and extensively, 1 , 2 , 5 , 14 , 17 as have the