Cortical mapping in glioma surgery: correlation of fMRI and direct electrical stimulation with Human Connectome Project parcellations

Abstract

OBJECTIVE Noninvasive brain mapping with functional MRI (fMRI) and mapping with direct electrical stimulation (DES) are important tools in glioma surgery, but the evidence is inconclusive regarding the sensitivity and specificity of fMRI. The Human Connectome Project (HCP) proposed a new cortical parcellation that has not been thoroughly tested in a clinical setting. The main goal of this study was to evaluate the correlation of fMRI and DES mapping with HCP areas in a clinical setting, and to evaluate the performance of fMRI mapping in motor and language tasks in patients with glioma, using DES as the gold standard. METHODS Forty patients with supratentorial gliomas were examined using preoperative fMRI and underwent awake craniotomy with DES. Functional activation maps were visualized on a 3D representation of the cortex, classified according to HCP areas, and compared with surgical mapping. RESULTS Functional MRI was successful in identifying language and motor HCP areas in most cases, including novel areas such as 55b and the superior longitudinal fasciculus (SLF). Functional MRI had a sensitivity and specificity of 100% and 71%, respectively, for motor function in HCP area 4. Sensitivity and specificity were different according to the area and fMRI protocol; i.e., semantic protocols performed better in Brodmann area (BA) 55b/peri-sylvian language areas with 100% sensitivity and 20% specificity, and word production protocols in BAs 44 and 45 with 70% sensitivity and 80% specificity. Some compensation patterns could be observed, such as motor activation of the postcentral gyrus in precentral gliomas. CONCLUSIONS HCP areas can be detected in clinical scenarios of glioma surgery. These areas appear relatively stable across patients, but compensation patterns seem to differ, allowing occasional resection of activating areas. Newly described areas such as 55b and SLF can act as critical areas in language networks. Surgical planning should account for these parcellations.

Awake craniotomies in South America: Advancements, challenges, and future prospects

“… 6 Subsequent to this pioneering use, the adoption and administration of AC procedures have progressively diffused across a multitude of South American nations, including Argentina, Brazil, and Chile, garnering positive acclaim. 4 , 5 , 7 , 8 …”

“…Despite being in the early phases of implementation within the region, various medical centres, such as Grupo Gamma Rosario Private Hospital in Argentina, Antonio Pedro University Hospital in Brazil, and Carlos van Buren Hospital in Chile, have successfully formulated and executed their own AC programs. 4 , 7 , 8 In addition, noteworthy practitioners in the region, including Dr Alicia Becerra in Peru, Dr Gabriela Moguilner in Paraguay, and Dr Tatiana Vilasboas in Brazil, have used their extensive expertise in the development, wide-scale dissemination, and implementation of AC in the region. 9 …”

“…Neurosurgical oncology in South America has undergone substantial development and advancement in the last decade, with notable progress observed in countries including Brazil, Chile, Colombia, and Uruguay. 5 , 8 , 13 - 15 The adoption of sophisticated technologies, such as neuro-navigation and intraoperative magnetic resonance imaging (MRI), has become increasingly prevalent across the region. 16 This widespread integration of advanced tools has contributed to enhanced efficacy and efficiency in neurosurgical interventions.…”

“… 7 AC via direct electrical stimulation (DES) is conducted, with DES being considered the gold standard. 8 Circles are drawn during the procedure to ensure no mismatches between the local anaesthetic and pin locations, utilizing tools such as ARTFIX (temporary fixation) for this purpose. 10 Language monitoring tests, alternating a name task in Portuguese and English, and a semantic task in Portuguese, are also incorporated.…”

“… 11 Albuquerque et al dehighlight that the concept of AC and the overall approach are rooted in a French model, which may not align well with the South American population. 11 While the number of studies detailing various South American nations’ experiences with AC procedures has increased in recent years, 5 , 7 , 8 , 10 there remains a scarcity of studies analysing how these initial experiences can be adapted into the broader South American context, as well as normative data from tests specific to the South American cohort.…”