The reliability of neuroanatomy as a predictor of eloquence: a review

Abstract

<jats:p>The adjacency of intracranial pathology to canonical regions of eloquence has long been considered a significant source of potential morbidity in the neurosurgical care of patients. Yet, several reports exist of patients who undergo resection of gliomas or other intracranial pathology in eloquent regions without adverse effects. This raises the question of whether anatomical and intracranial location can or should be used as a means of estimating eloquence. In this review, the authors systematically evaluate the factors that are known to affect anatomical-functional relationships, including anatomical, functional, pathology-related, and modality-specific sources of variability. This review highlights the unpredictability of functional eloquence based on anatomical features alone and the fact that patients should not be considered ineligible for surgical intervention based on anatomical considerations alone. Rather, neurosurgeons need to take advantage of modern technology and mapping techniques to create individualized maps and management plans. An individualized approach allows one to expand the number of patients who are considered for and who potentially may benefit from surgical intervention. Perhaps most importantly, an individualized approach to mapping patients with brain tumors ensures that the risk of iatrogenic functional injury is minimized while maximizing the extent of resection.</jats:p>

Mapping the hand, foot and face representations in the primary motor cortex — Retest reliability of neuronavigated TMS versus functional MRI

“…High test-retest reliability is mandatory for achieving valid results. This is particularly true when brain mapping techniques are used in clinical applications with strong impact on neurological functions like, e.g., preoperative mapping of motor cortex representations to achieve total tumor resection (Gorlia et al, 2008;Lacroix et al, 2001) while preserving neurological functions (Duffau et al, 2005;Pouratian and Bookheimer, 2010).…”

Multimodal Imaging in Malignant Brain Tumors: Enhancing the Preoperative Risk Evaluation for Motor Deficits with a Combined Hybrid MRI-PET and Navigated Transcranial Magnetic Stimulation Approach

“…The anatomic appearance of brain tissue can be heavily distorted by the tumor mass, especially for lesions close to the M1 and CST. 12 Likewise, previous studies did not consider nTMS mappings-that is, in putative lesions to motor cortical regions. Furthermore, previous studies primarily relied on T1-CE lesion volumes but did not consider metabolic information provided by PET.…”

“…For example, a useful tool for assessing the functional anatomy of the primary motor cortex in a noninvasive fashion is navigated transcranial magnetic stimulation (nTMS). [10][11][12] This technique has a reliability similar to that of fMRI mapping, however, with less demand for the cooperation of patients who may have reduced alertness, compliance, and functional impairment such as those with brain tumors. 13,14 Another technique that adds information to structure-function relationships is diffusion imaging, especially DTI.…”

“…19,20 In summary, there are currently rather limited data on how to preoperatively evaluate patients with brain tumors for operationassociated risks related to motor impairment and recovery thereof. 7,12,[21][22][23] Thus, the objective of our study was to use a multimodal imaging setup to delineate malignant brain tumor lesions from functionally relevant motor cortex and fibers in patients undergoing an operation. As such, the study was based on a multimodal imaging approach by the coregistered integration of the following: 1) MR imaging data for anatomically defining lesion extent (T2WI and T1WI) and allowing structural analysis by DTI tractography; 2) O-(2-…”

Surgical Strategies for Nonenhancing Slow-Growing Gliomas With Special Reference to Functional Reorganization: Review With Own Experience

“…4,24,28,39,40,46,48,71) Of note, although possible functional reorganization can be detected by preoperative fMR imaging, if the region of the possible functional reorganization is located in the surgical field, direct electrical stimulation (DES) should be performed intraoperatively to evaluate and confirm the findings of fMR imaging. In terms of the methods that can be used to observe brain functions, to overcome the limitations of presurgical neuroimaging, including fMR imaging, the current gold standard is DES that is based on reversibly inhibiting neuronal functions in certain areas.…”