Predicting the Extent of Resection in Low-Grade Glioma by Using Intratumoral Tractography to Detect Eloquent Fascicles Within the Tumor

Abstract

BACKGROUND An early maximal safe surgical resection is the current treatment paradigm for low-grade glioma (LGG). Nevertheless, there are no reliable methods to accurately predict the axonal intratumoral eloquent areas and, consequently, to predict the extent of resection. OBJECTIVE To describe the functional predictive value of eloquent white matter tracts within the tumor by using a pre- and postoperative intratumoral diffusion tensor imaging (DTI) tractography protocol in patients with LGG. METHODS A preoperative intratumoral DTI-based tractography protocol, using the tumor segmented volume as the only seed region, was used to assess the tracts within the tumor boundaries in 22 consecutive patients with LGG. The reconstructed tracts were correlated with intraoperative electrical stimulation (IES)-based language and motor subcortical mapping findings and the extent of resection was assessed by tumor volumetrics. RESULTS Identification of intratumoral language and motor tracts significantly predicted eloquent areas within the tumor during the IES mapping: the positive predictive value for the pyramidal tract, the inferior fronto-occipital fasciculus, the arcuate fasciculus and the inferior longitudinal fasciculus positive was 100%, 100%, 33%, and 80%, respectively, whereas negative predictive value was 100% for all of them. The reconstruction of at least one of these tracts within the tumor was significantly associated with a lower extent of resection (67%) as opposed to the extent of resection in the cases with a negative intratumoral tractography (100%) (P < .0001). CONCLUSION Intratumoral DTI-based tractography is a simple and reliable method, useful in assessing glioma resectability based on the analysis of intratumoral eloquent areas associated with motor and language tracts within the tumor.

Inferior fronto‐occipital fascicle displacement in temporoinsular gliomas using diffusion tensor imaging

“…Knowledge of the structural involvement and exact course of the tracts in oncological patients would provide useful information to guide tumor resection and minimize surgical morbidity. [4][5][6]12,24 F I G U R E 3 Patterns of tract displacement depending on main location of the tumor in the temporal lobe. Above (A-C) examples of medial location (A), lateral-medial location lesion (B), and lateral location lesions (C); 2-dimensional bilateral inferior frontal occipital fascicle trajectory on this slice is marked in orange.…”

“…As far as we are aware, this is the first study that aims to describe and predict the pattern of involvement and displacement of the IFOF by preoperative DTI. Knowledge of the structural involvement and exact course of the tracts in oncological patients would provide useful information to guide tumor resection and minimize surgical morbidity 4–6,12,24 …”

“…Precise mapping of brain structures is currently done by combining direct-electrical stimulation and neuromonitorization techniques during awake and asleep interventions with the guidance of presurgical MRI mapping techniques such as functional MRI and diffusion tensor imaging (DTI) tractography, which can be integrated into the operating room. [5][6][7] The anatomical components of this fasciculus have been studied extensively by ex vivo, surgical dissection, and in vivo neuroimaging MRI techniques such as DTI-tractography. [8][9][10][11] However, in the context of tumor surgery, little has been said about the precise patterns of involvement of the IFOF.…”

“…To avoid surgical damage and consequent postsurgical neurological deficits, functional brain mapping techniques aim to offer the maximum possible safe resection, optimizing patient survival while avoiding damage to essential eloquent cortical and subcortical structures, such as the IFOF. Precise mapping of brain structures is currently done by combining direct‐electrical stimulation and neuromonitorization techniques during awake and asleep interventions with the guidance of presurgical MRI mapping techniques such as functional MRI and diffusion tensor imaging (DTI) tractography, which can be integrated into the operating room 5–7 …”

Predictors of tumor progression of low-grade glioma in adult patients within 5 years follow-up after surgery

“…Therefore, Intraoperative resection of as many tumors as possible under the premise of ensuring safety is beneficial to obtain a better prognosis ( 26 ). If the preoperative assessment considers that the degree of tumor resection may be less than 50%, it can be considered biopsy under stereotaxic or navigation ( 27 , 28 ). Our findings are consistent with those described above.…”