Multi-modality Localization of Eloquent Brain Function

Accurate identification of areas of eloquent brain function is vital to surgical decision making and to preservation of independence as patients with brain tumors who are higher functioning have better survival outcomes. Eloquent brain is defined as a region controlling language, motor, or sensory function such that without its proper input, a person would be left with significant neurologic deficits. Imaging technology has evolved to provide multiple non-invasive modalities for pre-operative testing of eloquent brain function. Studies have shown that these non-invasive mapping modalities provide useful information, however, the information provided inconsistently predicts distribution of eloquent function.

Direct electrical stimulation (DES) at surgery allows assessment of eloquent function directly from the brain surface (invasive) and is considered the gold standard in brain mapping. Therefore, in order to determine the true clinical applicability of the non-invasive mapping technologies, this study proposes to assess the predictive value of functional MRI (fMRI) and magnetoencephalography (MEG) for sensorimotor and language functions by comparing results to DES and determine whether fMRI or MEG provides the most consistent and accurate information. The rationale for the proposed research is that understanding the reliability of our current technology will allow us to perform safer surgeries and to preserve neurologic function.

It is unknown whether imaging technologies have broad applications in brain mapping due to limited knowledge of the value of the results. Accurate identification of areas of eloquent brain function is vital to surgical decision making and to preservation of independence as patients with brain tumors who are higher functioning have better survival outcomes. Imaging technology has evolved to provide multiple non-invasive modalities for pre-operative testing of eloquent brain function and include functional MRI (fMRI) and magnetoencephalography (MEG). Eloquent brain is defined as a region controlling language, motor, or sensory function such that without its proper input, a person would be left with significant neurologic deficits. Studies conducted have shown that these non-invasive mapping modalities provide useful information, however, the information provided inconsistently predicts distribution of eloquent function.

Direct electrical stimulation (DES) at the time of surgery allows assessment of eloquent function directly from the brain surface (invasive) and is considered the gold standard in brain mapping. Therefore, in order to determine the true clinical applicability of the non-invasive mapping technologies, this study proposes to: (1) assess the predictive value of fMRI and MEG for sensorimotor and language functions by comparing their results to DES and (2) determine whether fMRI or MEG provides the most consistent and accurate information. These aims will be accomplished by by co-registering all mapping data (invasive and non-invasive) in a modifiable 3D rendering. In this way, the DES to fMRI and MEG can be evaluated as well as fMRI to MEG compared. The rationale for the proposed research is that understanding the reliability of our current technology will allow for safer surgeries and preservation of neurologic function. The expected outcomes for the work proposed in Aims 1 and 2 are identification of a predictive value for fMRI and MEG and determination if one modality should be utilized over the other pre-operatively for the most accurate information. The results of this study are expected to have an important positive impact because identification of accurate pre-operative non-invasive mapping modalities will allow tailored testing and possibly lead to negation of the need for intra-operative mapping in certain cases. It will also enhance patient outcomes by improving patient safety. Furthermore, it will serve as the basis for a multi-institutional mapping data bank.

Eligibility Criteria:
Inclusion Criteria:

* informed consent
* age equal to or greater than 19 years
* gender: male and female included
* brain tumor in or near an eloquent area of the brain that requires surgery
* benign or malignant intra-axial brain tumor
* primary or secondary intra-axial brain tumor
* appropriate body habitus for operating room positioning and airway protection for awake mapping
* appropriate mental status and capacity to participate with invasive or non-invasive mapping

Exclusion Criteria:

* any contraindication to MRI (i.e. implanted devices)
* inappropriate body habitus for safe positioning or airway protection
* no capacity to understand the study the study or consent to it
* significant disability precluding successful mapping
* positive pregnancy test in females
* end stage renal disease or severe renal dysfunction
* sleep apnea or any obstructive airway disease
* severe anxiety disorder
* metabolic encephalopathy