A Novel Sequence: ZOOMit-Blood Oxygen Level-Dependent for Motor-Cortex Localization

Abstract

BACKGROUND Use of conventional blood oxygen level-dependent functional magnetic resonance imaging (conventional-BOLD-fMRI) presents challenges in accurately identifying the hand-motor cortex when a glioma involves the ipsilateral hand-knob. Zoomed imaging technique with parallel transmission (ZOOMit)-BOLD is a novel sequence allowing high spatial resolution with a relatively small field of view that may solve this problem. OBJECTIVE To compare the accuracy of ZOOMit-BOLD and conventional-BOLD in hand-motor cortex identification. METHODS A total of 20 patients with gliomas involving the sensorimotor cortex were recruited to identify the hand-motor cortex by both ZOOMit-BOLD and conventional-BOLD. Based on whether the entire or partial glioma directly invaded (was located within) the hand-knob or indirectly affected it by proximity, patients were placed into the involved or uninvolved groups, respectively. Direct cortical stimulation was applied intraoperatively to verify the location of the hand-motor cortex. Overlap indices were used to evaluate the accuracy of the hand-motor cortex identification. An overlap index equal to 0, indicating lack of overlap, was classified as inaccurate classification. RESULTS The accuracy of motor-cortex identification with ZOOMit-BOLD was 100% compared to only 65% with conventional-BOLD. The average overlap index yielded by ZOOMit-BOLD was higher than that of conventional-BOLD, regardless of whether gliomas directly invaded the hand-knob (P = .008) or not (P = .004). The overlap index in the involved group was significantly lower than that in the uninvolved group with both ZOOMit-BOLD (P = .002) and conventional-BOLD (P < .001). CONCLUSION ZOOMit-BOLD may potentially replace conventional-BOLD to identify the hand-motor cortex, particularly in cases in which gliomas directly invade the hand-knob.

Intra-operative mapping and language protection in glioma

“…[48,49] Moreover, neurovascular uncoupling is an inevitable effect that leads to a decrease in the accuracy of the fMRI location. [50,51] Consequently, solely using fMRI to identify language-related cortices and guide glioma resection is not recommended. Hence, fMRI normally serves as the primary source for guidance for language mapping with direct cortical stimulation (DCS) during the clinical practice.…”

“…Additionally, patients were unable to perform many tasks at one time [48,49] . Moreover, neurovascular uncoupling is an inevitable effect that leads to a decrease in the accuracy of the fMRI location [50,51] . Consequently, solely using fMRI to identify language-related cortices and guide glioma resection is not recommended.…”

The new morphologic classification of the hand motor cortex with magnetic resonance imaging in glioma patients

“…The hand motor cortex (HMC), which is also known as the “hand knob”, has been widely accepted as a reliable anatomical landmark for identifying the precentral gyrus on MRI [ 3 , 4 ]. To date, various modalities have been applied to locate HMC and investigate its morphological features [ 5 , 6 , 7 , 8 ]. In 1997, Yousry et al first defined a knob-like structure for identifying the precentral gyrus directly, which is shaped like an omega (Ω) in the axial plane [ 9 ].…”

Intraoperative Neuromonitoring During Resection of Gliomas Involving Eloquent Areas

“…Regarding the technologies for achieving brain mapping, intraoperative functional neuronavigations are commonly applied in glioma resection, which combine with preoperative functional MRI [blood oxygen level dependent MRI and diffusion tensor imaging (DTI) MRI] ( 3 , 4 ) to determine the brain functional localization. However, DTI cannot display the entire cortico-subcortical circuits, and the accuracy for exhibiting the anatomic regions depends on the fiber tracking software packages employed ( 5 , 6 ).…”