Background/Objectives: Glioblastoma (GBM) is the most common primary malignant central nervous system tumor, accounting for 50.9% of malignant CNS diagnoses and carrying a median survival of 15 months despite maximal standard therapy. High recurrence rates are driven by residual infiltrative tumor cells at the resection margin. Fluorescence-guided surgery (FGS) has emerged as a key innovation to improve intraoperative tumor visualization and maximize the extent of resection (EOR). This review examines the historical development, current clinical applications, and future directions of FGS in GBM surgery. Methods: A comprehensive literature review was conducted, covering the evolution of fluorophores (fluorescein, indocyanine green [ICG], and 5-aminolevulinic acid [5-ALA]), visualization technologies (wide- and narrow-field modalities), therapeutic adjuncts (photodynamic and sonodynamic therapies), and clinical adoption patterns and outcomes. Results: Early intraoperative fluorescence using fluorescein dates to 1947. ICG angiography has broad surgical utility, while 5-ALA received FDA approval in 2017, with phase III trials demonstrating gross total resection rates of 65% versus 36% with white-light surgery. Adjunct technologies—3D exoscopes, FGS-compatible loupes, and quantitative spectroscopy probes—enhance detection of residual tumor. Preliminary studies of intraoperative photodynamic and sonodynamic therapies show feasibility and potential survival benefits. Global adoption of 5-ALA FGS exceeds 75% among surveyed neurosurgeons. Conclusions: FGS significantly improves EOR in GBM surgery, translating into better patient outcomes. Ongoing clinical trials and technological refinements—novel fluorophores, quantitative imaging, and therapeutic applications—promise to further optimize tumor visualization and treatment.

Objective: Thalamic responsive neurostimulation (RNS) is a surgical option for patients with drug‐refractory epilepsy. However, it is unclear whether thalamic connectivity with the seizure onset zone (SOZ) has a role in clinical outcomes. Here, we aim to investigate the clinical utility of the connectivity between the SOZ and the thalamus for thalamic RNS targeting. Methods: Retrospective analysis was made of 12 patients treated with thalamic RNS. Clinical features and Engel scores were recorded. Patients were divided into responders, partial responders, and nonresponders based on seizure frequency reduction at last follow‐up. Structural connectivity between the SOZ and the whole thalamus was calculated using patient‐specific tractography. RNS electrodes were used to model the volume of tissue activated (VTA) with stimulation parameters at last follow‐up based on individualized electrode locations. The patient's VTAs were then used to identify thalamic areas with high or low probability of connectivity with the SOZ and how they were associated and correlated with clinical outcomes using nonparametric Mann–Whitney U and Spearman correlation tests. Results: Seven patients were responders, three nonresponders, and two partial responders. Thalamic nuclei targeted included anterior nucleus of thalamus and centromedian nucleus. Cortical areas of the SOZs included medial prefrontal, supplementary motor, cingulate, orbitofrontal, insular, mesial temporal, and lateral temporal cortices. Stimulation of thalamic areas with higher connectivity between the SOZ and the thalamus was associated with a clinical response of >50% reduction in seizures ( p = .017). Furthermore, higher degree of tract activation between the SOZ and the thalamus was correlated with better seizure outcomes at last follow‐up ( r = .78, p = .004). Significance: Greater recruitment of white matter connections between the SOZ and thalamus is associated with clinical response and may correlate with improved seizure outcomes during thalamic RNS. Using tractography to map the patient‐specific “thalamic seizure network” and the surgical targeting of these connections may result in improved clinical outcomes in patients treated with thalamic RNS.

Diffusion magnetic resonance imaging (dMRI) allows for a non-invasive visualization and quantitative assessment of white matter architecture in the brain by characterizing restrictions on the random motion of water molecules. Ultra-high field MRI scanners, such as those operating at 7 Tesla (7T) or higher, can boost the signal-to-noise ratio (SNR) to improve dMRI compared with what is attainable at conventional field strengths such as 3T or 1.5T. However, wavelength effects at 7T cause reduced transmit magnetic field efficiency in the human brain, mainly in the posterior fossa, manifesting as signal dropouts in this region. Recently, we reported a simple approach of using a wireless radiofrequency (RF) surface array to improve transmit efficiency and signal sensitivity at 7T. In this study, we demonstrate the feasibility and effectiveness of the RF enhancer in improving in vivo dMRI at 7T. The electromagnetic simulation results demonstrated a 2.1-fold increase in transmit efficiency with the use of the RF enhancer. The experimental results similarly showed a 1.9-fold improvement in transmit efficiency and a 1.4-fold increase in normalized SNR. These improvements effectively mitigated signal dropouts in regions with inherently lower SNR, such as the cerebellum, resulting in a better depiction of principal fiber orientations and an enhanced visualization of extended tracts.

Accurate localization of the ventral intermediate nucleus (VIM) within the dentatorubrothalamic tract (DRTT) is critical for effective neurosurgical treatment of essential tremor (ET). This study evaluated the feasibility and anatomical specificity of quantitative susceptibility mapping (QSM) for direct VIM/DRTT visualization, comparing it with conventional diffusion tractography-based reconstructions. Twenty-seven participants (10 healthy controls, 17 ET patients) were enrolled across two institutions and imaged on 3T MRI systems. QSM-defined VIM/DRTT regions were manually segmented based on characteristic hypointense susceptibility contrast. Whole-brain diffusion tractography was performed to reconstruct the DRTT, pyramidal tract (PT), and medial lemniscus (ML) tracts. Spatial overlap between QSM-and tractography-defined VIM/DRTT regions was calculated, as well as overlap with neighboring PT and ML tracts to assess specificity. Two participants were excluded due to insufficient VIM/DRTT streamlines in tractography reconstruction. In healthy controls, QSM-and tractography-defined VIM/DRTT showed high spatial correspondence (left: 87.6 ± 5.1%; right: 85.3 ± 6.5%). ET patients exhibited slightly lower overlap (mean range: 71.5 - 85.1%). Overlap with neighboring PT and ML tracts was minimal (<3.3%), confirming high anatomical specificity of QSM-derived VIM/DRTT regions. QSM enables direct visualization of the VIM/DRTT with high spatial agreement to conventional tractography-based approaches while demonstrating minimal overlap with adjacent tracts. These findings support QSM as a complementary or standalone imaging modality for improved, patient-specific neurosurgical targeting in ET. DBS = deep brain stimulation; DRTT = dentatorubrothalamic tract; ET = essential tremor; ML = medial lemniscus; MRgFUS = MR-guided focused ultrasound; VIM = ventral intermediate nucleus; PT = pyramidal tract; QSM = quantitative susceptibility mapping; WM = white matter.