Search Results

You are looking at 1 - 10 of 461 items for :

  • Refine by Access: all x
Clear All
Free access

Juan Delgado-Fernández, Maria Ángeles García-Pallero, Rafael Manzanares-Soler, Pilar Martín-Plasencia, Guillermo Blasco, Natalia Frade-Porto, Marta Navas-García, Paloma Pulido, Rafael G. Sola, and Cristina V. Torres

Nevertheless, some patients without good outcomes in epilepsy surgery could benefit from further imaging, such as diffusion tensor imaging (DTI). 14 , 15 DTI has demonstrated its utility in describing the microstructure of white matter tracts and defining fascicules and bundles in preoperative planning. In addition, fractional anisotropy (FA), which describes the degree of anisotropy of a diffusion process, 16 is a very useful tool that helps us to understand the structural integrity of axons and myelin sheaths. 17 , 18 Moreover, there are a large number

Restricted access

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

Free access

Anna Zdunczyk, Fabia Roth, Thomas Picht, and Peter Vajkoczy

dependence of a diffusion process. 11 , 13 This can therefore also be used as a measure of diffusion along neuronal axons, indicating tract integrity. Recent studies have pointed out the benefit of diffusion tensor imaging (DTI) in determining the association between the lesion and the white matter tracts in order to establish the best neurosurgical approach 8 , 14–18 in deep-seated lesions. However, no clear correlation between DTI parameters and postoperative outcomes has been demonstrated. 16 , 17 , 19 Navigated transcranial magnetic stimulation

Full access

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

Restricted access

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

Restricted access

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

Free access

Ana M. Castaño-Leon, Marta Cicuendez, Blanca Navarro-Main, Igor Paredes, Pablo M. Munarriz, Amaya Hilario, Ana Ramos, Pedro A. Gomez, and Alfonso Lagares

, respectively. 2–5 Therefore, many authors 2 , 6–11 have described the association between long-term outcome and MRI findings according to the nature, number, volume, and location of lesions. A more recent technique, diffusion tensor imaging (DTI), 12 can provide different metrics that indirectly represent the microstructural integrity and orientation of white matter (WM). Fractional anisotropy (FA), which quantifies the degree of diffusion restriction in a particular direction, 13 is considered the most sensitive biomarker of WM among other DTI metrics. 14 , 15 The

Full access

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

Free access

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

Free access

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