Clinical Services

Clinical Services

Pre-surgical planning:

Pre Surgical Planning sections include two main areas: fMRI and DTI.

fMRI:

Functional magnetic resonance imaging (fMRI) is a non-invasive pre-surgical tool used to map task-related brain activation in brain tumor and vascular lesion patients in order to guide neurosurgeons as they devise a surgical approach to treat these lesions and minimizes post-operative neurological deficits.

Functional Magnetic Resonance Imaging (fMRI) can be used to define brain regions which must be left intact when patients undergo surgery. The critical function is mapped with fMRI using a relevant task. These maps are generated from changes in the blood oxygen level-dependent (BOLD) signal related to neural activity. Task-based functional MRI (fMRI) has been used successfully for pre-surgical localization of brain activated regions prior to the performance of brain surgery. To date, usage of fMRI in pre-surgical planning has played a valuable role in neurosurgical procedures. In our pre-surgical Analysis group, for each patient we use various types of language, Memory and Motor Tasks, based on individual medical conditions (tumor region) and neurosurgeons request to help the neuro-surgical team evaluate specific function. All tasks followed a block design paradigm and Patients are instructed to perform tasks before scanning. fMRI data is analyzed using FEAT (FMRI Expert Analysis Tool), part of FSL (FMRIB’s Software Library, www.fmrib.ox.ac.uk/fsl)

DTI:

Diffusion tensor imaging (DTI) uses water diffusion to estimate white matter (WM) tract directionality. Water diffuses parallel to axonal fibers and is restricted in the perpendicular direction. This directionality is termed anisotropy. Diffusion is anisotropic (directionally dependent) in WM fiber tracts, as axonal membranes and myelin sheaths present barriers to the motion of water molecules in directions not parallel to their own orientation. The direction of maximum diffusivity has been shown to coincide with the WM fiber tract orientation.

The goal of surgical treatment for cerebral neoplasms is to maximize the extent of tumor resection while minimizing postoperative neurologic deficits resulting from damage to an intact, functioning brain. This requires preoperative or intraoperative mapping of the tumor and its relationship to functional structures, including the cerebral cortex and WM tracts. Cortical mapping can be accomplished with either functional MR imaging or intraoperative electrocortical for depicting the relationship of the tumor to WM tracts. DTI is uniquely suited for this role. The altered states of WM resulting from cerebral neoplasm might be expected to influence the measurement of diffusion tensor anisotropy and orientation in various ways, resulting in several possible patterns on directional DTI color maps. Intact WM tracts displaced by tumor might retain their anisotropy and remain identifiable in their new location or orientation on directional DTI color maps. Edematous or tumor-infiltrated tracts might lose some anisotropy but retain enough directional organization to remain identifiable on directional DTI maps. Finally, WM tracts might be destroyed or disrupted to the point where a directional organization (and, consequently, diffusion anisotropy) is lost completely.

Brain mapping:

  • Seizure Mapping
  • Tumor Mapping
  • MS Mapping
  • Stroke Mapping

Neuroimaging protocol:

  • MRS
  • Perfusion
  • Diffusion and DTI measurement
  • Structural Imaging
  • Corticometry
  • Volumetry
    • VBM
    • Volume measurements

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