Preoperative Diffusion Tensor Imaging Research Articles

Utility of diffusion tensor imaging and generalized q-sampling imaging for predicting short-term clinical effect of deep brain stimulation in Parkinson’s disease

PurposeTo assess whether diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI) metrics could preoperatively predict the clinical outcome of deep brain stimulation (DBS) in patients with Parkinson’s disease (PD).MethodsIn this single-center retrospective study, from September 2021 to March 2023, preoperative DTI and GQI examinations of 44 patients who underwent DBS surgery, were analyzed. To evaluate motor functions, the Unified Parkinson’s Disease Rating Scale (UPDRS) during on- and off-medication and Parkinson’s Disease Questionnaire-39 (PDQ-39) scales were used before and three months after DBS surgery. The study population was divided into two groups according to the improvement rate of scales: ≥ 50% and < 50%. Five target regions, reported to be affected in PD, were investigated. The parameters having statistically significant difference were subjected to a receiver operating characteristic (ROC) analysis.ResultsQuantitative anisotropy (qa) values from globus pallidus externus, globus pallidus internus (qa_Gpi), and substantia nigra exhibited significant distributional difference between groups in terms of the improvement rate of UPDRS-3 scale during on-medication (p = 0.003, p = 0.0003, and p = 0.0008, respectively). In ROC analysis, the best parameter in predicting DBS response included qa_Gpi with a cut-off value of 0.01370 achieved an area under the ROC curve, accuracy, sensitivity, and specificity of 0.810, 73%, 62.5%, and 85%, respectively. Optimal cut-off values of ≥ 0.01864 and ≤ 0.01162 yielded a sensitivity and specificity of 100%, respectively.ConclusionThe imaging parameters acquired from GQI, particularly qa_Gpi, may have the ability to non-invasively predict the clinical outcome of DBS surgery.

Intraventricular meningioma resection and visual outcomes.

Intraventricular meningiomas (IVMs) of the lateral ventricle are rare tumors that present surgical challenges because of their deep location. Visual field deficits (VFDs) are one risk associated with these tumors and their treatment. VFDs may be present preoperatively due to the tumor and mass effect (tumor VFDs) or may develop postoperatively due to the surgical approach (surgical VFDs). This institutional series aimed to review surgical outcomes following resection of IVMs, with a focus on VFDs. Patients who received IVM resection at one academic institution between the years 1996 and 2021 were retrospectively reviewed. Diffusion tensor imaging (DTI) reconstructions of the optic radiations around the tumor were performed from preoperative IVM imaging. The VFD course and resolution were documented. Thirty-two adult patients underwent IVM resection, with gross-total resection in 30 patients (93.8%). Preoperatively, tumor VFDs were present in 6 patients, resolving after surgery in 5 patients. Five other patients (without preoperative VFD) had new persistent surgical VFDs postoperatively (5/32, 15.6%) that persisted to the most recent follow-up. Of the 5 patients with persistent surgical VFDs, 4 received a transtemporal approach and 1 received a transparietal approach, and all these deficits occurred prior to regular use of DTI in preoperative imaging. New surgical VFDs are a common neurological deficit after IVM resection. Preoperative DTI may demonstrate distortion of the optic radiations around the tumor, thus revealing safe operative corridors to prevent surgical VFDs.

A diffusion tensor imaging comparison of white matter development in nonsyndromic craniosynostosis to neurotypical infants.

Nonsyndromic craniosynostosis (NSC) is associated with neurocognitive deficits, and intervention at infancy is standard of care to limit the negative effects of NSC on brain development. In this study, diffusion tensor imaging (DTI) was implemented to investigate white matter microstructure in infants with NSC undergoing cranial vault remodeling, and a comparison was made with white matter development in neurotypical controls. Infants presenting with NSC (n = 12) underwent DTI scans before and after cranial vault remodeling. Neurotypical infants (n = 5), age matched to NSC patients at preoperative scans, were compared to preoperative DTI scans. Pre- and postoperative NSC scans were compared in aggregate, and the sagittal synostosis (n = 8) patients were evaluated separately. Finally, neurotypical infants from the University of North Carolina/University of New Mexico Baby Connectome Project (BCP), who underwent DTI scans at timepoints matching the NSC pre- and postoperative DTI scans, were analyzed (n = 9). Trends over the same time period were compared between NSC and BCP scans. No significant differences were found between preoperative NSC scans and controls. White matter development was more limited in NSC patients than in BCP patients, with microstructural parameters of the corpus body and genu and inferior and superior longitudinal fasciculi consistently lagging behind developmental changes observed in healthy patients. Infant white matter development appears more limited in NSC patients undergoing cranial vault remodeling relative to that in neurotypical controls. Further investigation is needed to explore these differences and the specific effects of early surgical intervention.

Correlation Between Pre-Operative Diffusion Tensor Imaging Indices and Post-Operative Outcome in Degenerative Cervical Myelopathy: A Systematic Review and Meta-Analysis.

Systematic review. The correlation between pre-operative diffusion tensor imaging (DTI) metrics and post-operative clinical outcomes in patients with degenerative cervical myelopathy (DCM) has been widely investigated with different studies reporting varied findings. We conducted a systematic review to determine the association between DTI metric and clinical outcomes after surgery. We identified relevant articles that investigated the relationship between pre-operative DTI indices and post-operative outcome in DCM patients by searching PubMed/MEDLINE, Web of Science, Scopus, and EMBASE from inception until October 2023. In addition, quantitative synthesis and meta-analyses were performed. FA was significantly correlated with postoperative JOA or mJOA across all age and follow up subgroups, changes observed in JOA or mJOA from preoperative to postoperative stages (Δ JOA or Δ mJOA) in subgroups aged 65 and above and in those with a follow-up period of 6 months or more, as well as recovery rate in all studies pooled together and also in the under-65 age bracket. Additionally, a significant correlation was demonstrated between recovery rate and ADC across all age groups. No other significant correlations were discovered between DTI parameters (MD, AD, and ADC) and post-operative outcomes. DTI is a quantitative noninvasive evaluation tool that correlates with severity of DCM. However, the current evidence is still elusive regarding whether DTI metric is a validated tool for predicting the degree of post-operative recovery, which could potentially be useful in patient selection for surgery.

White matter tracts contribute selectively to cognitive functioning in patients with glioma.

The functional organization of white matter (WM) tracts is not well characterized, especially in patients with intrinsic brain tumors where complex patterns of tissue injury, compression, and neuroplasticity may be present. This study uses diffusion tensor imaging (DTI) to investigate the relationships between WM tract disruption and cognitive deficits in glioma patients. Seventy-nine patients with glioma underwent preoperative DTI and neuropsychological testing. Thirteen WM tracts were reconstructed bilaterally. Fractional anisotropy and streamline number were obtained for each tract as indices of connectivity. Univariate regression models were used to model the association between WM tract connectivity and neuropsychological outcomes. Glioma patients exhibited variable injury to WM tracts and variable cognitive deficits on validated neuropsychological tests. We identified 16 age-adjusted associations between WM tract integrity and neuropsychological function. The left inferior frontal-occipital fasciculus (IFOF) predicted list learning and dominant-hand fine motor dexterity. The right IFOF predicted non-dominant-hand fine motor dexterity and visuospatial index scores. The left inferior longitudinal fasciculus (ILF) predicted immediate memory list learning and index scores. The right ILF predicted non-dominant-hand fine motor dexterity and backward digit span scores. The left superior longitudinal fasciculus (SLF) I predicted processing speed. The left SLF III predicted list learning, immediate memory index scores, phonemic fluency, and verbal abstract reasoning. The left cingulum predicted processing speed. The right anterior AF predicted verbal abstract reasoning. WM tract disruption predicts cognitive dysfunction in glioma patients. By improving knowledge of WM tract organization, this analysis may guide maximum surgical resection and functional preservation in glioma patients.

Preoperative Diffusion Tensor Imaging in Supratentorial Intra-Axial Brain Tumors: Its Role in Predicting Tumor Histology and Prognosis as well in Surgical Planning and Resection.

Objective There are a large number of prospective studies that use diffusion tensor imaging (DTI) to show the relationship between intracranial tumors and white matter (WM) fibers. We studied the role of DTI in supratentorial intra-axial (ST-IA) tumors of the brain in deciding the surgical approach with maximal resection and minimal or no deficit and in predicting the histological characterization of the tumor and the neurological outcome. Methods A total of 91 cases of ST-IA tumors were included in our study. The neurological status of the patients was assessed preoperatively, and the tumor volume and DTI pattern were noted radiologically. Surgical plan was decided by the senior consultants of the neurosurgery department taking into consideration the findings of tractography and magnetic resonance imaging. The neurological status and the extent of resection were evaluated postoperatively, and the correlation between histopathology with DTI was studied. Results Of the 91 patients, 25 had high-grade glioma (HGG), 60 had low-grade glioma (LGG), and 6 were metastatic lesions. Gross total excisions were done mostly in patients with DTI showing displaced fibers and subtotal/partial resections were done mostly in disrupted/infiltrated tracts, which was statistically significant. The correlation between histopathology and tractography revealed that intact/displaced tracts were seen mostly in LGG (79%), whereas 86% of HGG showed disrupted/infiltrated fibers; both were statistically significant. Conclusion Preoperative DTI in ST-IA brain tumors is an important tool for deciding the appropriate surgical approach for maximal safe resection, thus improving the post-op neurological outcome in patients. It also helps in predicting the tumor histology while also serving as an important prognostication indicator.

Preoperative tractography algorithm for safe resection of tumors located in the descending motor pathways zone.

Diffusion tensor imaging (DTI) tractography facilitates maximal safe resection and optimizes planning to avoid injury during subcortical dissection along descending motor pathways (DMPs). We provide an affordable, safe, and timely algorithm for preoperative DTI motor reconstruction for gliomas adjacent to DMPs. Preoperative DTI reconstructions were extracted from a prospectively acquired registry of glioma resections adjacent to DMPs. The surgeries were performed over a 7-year period. Demographic, clinical, and radiographic data were extracted from patients' electronic medical records. Nineteen patients (12 male) underwent preoperative tractography between January 1, 2013, and May 31, 2020. The average age was 44.5 years (range, 19-81 years). A complete radiological resection was achieved in nine patients, a subtotal resection in five, a partial resection in three, and a biopsy in two. Histopathological diagnoses included 10 patients with high-grade glioma and nine with low-grade glioma. A total of 16 perirolandic locations (10 frontal and six frontoparietal) were recorded, as well as two in the insula and one in the basal ganglia. In 9 patients (47.3%), the lesion was in the dominant hemisphere. The median preoperative and postoperative Karnofsky Performance Scores were 78 and 80, respectively. Motor function was unchanged or improved over time in 15 cases (78.9%). This protocol of DTI reconstruction for glioma removal near the DMP shows good results in low-term neurological functional outcomes.

Predicting Isocitrate Dehydrogenase Mutation Status of Grade 2–4 Gliomas with Diffusion Tensor Imaging (DTI) Parameters Derived from Model-Based DTI and Model-Free Q-Sampling Imaging Reconstructions

To determine whether diffusion tensor imaging (DTI) parameters acquired with model-based DTI and model-free generalized Q-sampling imaging (GQI) reconstructions may noninvasively predict isocitrate dehydrogenase (IDH) mutational status in patients with grade 2-4 gliomas. Forty patients with known IDH genotype (28 IDH wild-type; 12 IDH mutant) who underwent preoperative DTI evaluation on a 3-Tesla magnetic resonance imaging scanner were analyzed retrospectively. Absolute values obtained from model-based and model-free reconstructions were compared. Using the intraclass correlation coefficient, interobserver agreement was assessed for various sampling techniques. Variables having statistically significant distributions between IDH groups were subjected to a receiver operating characteristic (ROC) analysis. Using multivariable logistic regression analysis, independent predictors, if present, were identified and a model was developed. Six imaging parameters (3 from model-based DTI and 3 from model-free GQI reconstructions) showed statistically significant differences between groups (P < 0.001, power >0.97), with very high correlation to each other (P < 0.001). Age difference between the groups was statistically significant (P < 0.001). The optimal logistic regression model comprised a GQI-based parameter and age, which were independent predictors as well, producing an area under the ROC curve, accuracy, sensitivity, and specificity of 0.926, 85%, 75%, and 89.3%, respectively. Using the GQI reconstruction feature alone with a cut-off of 1.60, an 85% of accuracy was also achieved with ROC analysis. The imaging parameters acquired from model-based DTI and model-free GQI reconstructions, combined with the clinical variable age, may have the ability to noninvasively predict the IDH genotype in gliomas, either alone or in particular combinations.

How to combine the use of intraoperative magnetic resonance imaging (MRI) and awake craniotomy for microsurgical resection of hemorrhagic cavernous malformation in eloquent area: a case report

BackgroundCavernous malformations are clusters of abnormal and hyalinized capillaries without interfering brain tissue. Here, we present a cavernous malformation operated under awake conditions, due to location, in an eloquent area and using intraoperative magnetic resonance imaging due to patient’s movement upon the awake phase.Case presentationWe present the pre-, per-, and postoperative course of an inferior parietal cavernous malformation, located in eloquent area, in a 27-year-old right-handed Caucasian male, presenting with intralesional hemorrhage and epilepsy. Preoperative diffusion tensor imaging has shown the cavernous malformation at the interface between the arcuate fasciculus and the inferior fronto-occipital fasciculus. We describe the microsurgical approach, combining preoperative diffusion tensor imaging, neuronavigation, awake microsurgical resection, and intraoperative magnetic resonance imaging.ConclusionComplete microsurgical en bloc resection has been performed and is feasible even in eloquent locations. Intraoperative magnetic resonance imaging was considered an important adjunct, particularly used in this case as the patient moved during the “awake" phase of the surgery and thus neuronavigation was not accurate anymore. Postoperative course was marked by a unique, generalized seizure without any adverse event. Immediate and 3 months postoperative magnetic resonance imaging confirmed the absence of any residue. Pre- and postoperative neuropsychological exams were unremarkable.

A Diffusion Tensor Imaging-Based Prognostic Classification for Surgery of Intrinsic Lesions Involving the Motor Pathways.

The critical role of different adjuncts in improving the neurological outcome in intrinsic brain lesions affecting eloquent areas is demonstrated by their more diffuse utilization. Neurosurgeons often rely on preoperative and intraoperative diffusion tensor imaging tractography to improve the operative strategy and prognosis. We aimed to identify and validate a diffusion tensor imaging-based classification considering the relationship between the brain lesion and the corticospinal tract to predict a >50% reduction of motor evoked potentials (MEPs) during surgical excision of lesions involving the motor pathways. We included patients consecutively enrolled at our institution between April 2020 and September 2022 with 3 patterns of increasing complexity according to the relationship between the lesion and the corticospinal tract as identified on preoperative diffusion tensor imaging. Outcome measures were >50% reduction in intraoperative MEPs and neurological outcome defined as unchanged, improved, or worsened. The study included 83 patients. A statistically significant linear trend between higher rates of reduction of MEPs and higher classification grades was observed (P= 0.001), with sensitivity 0.60, specificity 0.88, accuracy 0.83, and area under the curve 0.75. Higher grades were associated with worse neurological outcomes (P= 0.02). The classification proved reliable in anticipating reduction in intraoperative MEPs and in predicting neurological outcome. Using this classification in patients undergoing surgery for lesions involving the motor pathways could help in counseling the patient, surgical planning, enhancing teamwork of operating room personnel, and improving the patient's prognosis.

160 The Neurosurgical Anatomy of Deficits in Speech Production

INTRODUCTION: Why do similar neurosurgical lesions cause a range of deficits in speech production? We investigated Broca’s aphasia as a disorder of fluency and apraxia of speech (AOS) as a disorder of articulatory coordination to dissociate the anatomy and lesional etiology of these syndromes. METHODS: Patients were prospectively tested with a standardized speech paradigm. Resections were outlined into 3D regions of interest and transformed into a common brainspace (MNI brain). Recordings of speech were retrospectively review by speech language experts to assess apraxia of speech. A voxel-based lesion-mapping (VLSM) algorithm was used to associate resection areas with acute postoperative aphasia or apraxia of speech. Averages of white-matter tracts were overlaid onto MNI reconstructions for analyses of white-matter tract involvement. Pre-operative diffusion tensor imaging reconstructions were created using peri-lesional regions of interest for seeds to investigate perilesional white matter tracts in these cohorts. RESULTS: Of 289 patients with left sided craniotomies and prospective language evaluation, 19 had Broca’s aphasia. 255 of these patients had recordings available for expert review, of whom 28 had apraxia of speech. VLSM analysis found Broca’s aphasia and fluency deficits were not associated with classic anatomic Broca’s area (pars opercularis and triangularis). Rather, they were associated with ventral sensorimotor cortex (SMC) and supramarginal gyrus (P &lt; 0.001). Apraxia of speech was associated the most ventral aspects of SMC (P &lt; 0.001). SLF III reconstructions terminated in the areas associated with Broca’s aphasia and fluency deficits, but had more limited overlap with the VLSM regions associated with apraxia of speech. CONCLUSIONS: Lesions leading to AOS and Broca’s aphasia after neurosurgical resection do not correlate with Broca's area. Rather, they cluster in ventral sensorimotor cortex. Subcortical white-matter tract injury may explain disparate non-fluent aphasia subtypes in patients with anatomically similar lesions.

Can Preoperative Diffusion Tensor Imaging Tractography Predict the Visual Outcomes of Patients with Pituitary Macroadenomas? A Prospective Pilot Study.

Visual impairment has been reported as the most common clinical manifestation of pituitary adenoma (PA) due to the compressive effect of the tumor. This prospective study aimed to evaluate the predictive role of diffusion tensor imaging (DTI) in the visual improvement of patients with PA, who were candidates for endoscopic endonasal surgery. A total of 13 patients (male, 8; female, 5) with visual impairment due to pituitary macroadenoma were enrolled in this study. The DTI findings and visual parameters, including visual acuity (VA), visual field (VF), and visual evoked potential (VEP), were recorded for all participants before and 3months after surgery. Significant recovery was reported in both VA and VF following PA surgery (P < 0.001). The results of perimetry indicated recovery in all quadrants, except for the lower nasal quadrant of the right eye. The tumor volume showed no significant association with the preoperative optic nerve, optic tract, and chiasm fractional anisotropy (FA) or mean diffusivity (MD). The VA and VF recoveries were more likely in patients with a lower preoperative optic nerve MD. Besides, increased preoperative FA of the optic nerve was associated with a higher probability of VA recovery. No significant correlation was found between the optic tract MD and FA values and visual improvement. Overall, MD values below 0.0021 and FA values above 0.1689 could predict a good prognosis of VA recovery after surgery. DTI may have a predictive value in estimating visual improvement in patients with PA preoperatively.

The Prediction of Neurological Prognosis for Cervical Spondylotic Myelopathy Using Diffusion Tensor Imaging.

Although cervical spondylotic myelopathy (CSM) can be easily diagnosed using magnetic resonance imaging (MRI), prediction of surgical effect using preoperative radiological examinations remains difficult. In previous studies, it was reported that diffusion tensor imaging (DTI) may be used for the prediction of surgical effect; however, these studies did not consider the influences of spinal cord compression even though the values of DTI indexes can be distorted by compressive lesions in patients with CSM. Therefore, it is uncertain whether preoperative DTI indexes can actually predict the surgical effect. The aim of this study was to investigate DTI metrics that are hardly affected by spinal cord compression and can accurately predict neurological status after decompressive surgery. Twenty-one patients with CSM who underwent surgery and 10 healthy volunteers were enrolled in this study. The subjects underwent cervical MRI, and values of DTI indexes including axial diffusivity (AD), radial diffusivity (RD), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were recorded at each intervertebral level. Further, the Japanese Orthopaedic Association (JOA) score of each patient with CSM was recorded before and after surgery for neurological status evaluation. Preoperative and postoperative values of DTI indexes were compared, and correlations between preoperative DTI parameters and postoperative neurological recovery were assessed. After surgery, the lesion-adjacent (LA) ratios of RD and ADC increased (p = 0.04 and p = 0.062, respectively), while the LA ratio of FA decreased (p = 0.075). In contrast, the LA ratio of AD hardly changed. A negative correlation was observed between preoperative LA ratio of AD and JOA recovery rate 6 months after surgery (r = -0.379, p = 0.091). Based on preoperative LA ratio of AD, the patients were divided into a low AD group and a high AD group, and JOA recovery rate 6 months after surgery was found to be higher in the low AD group than in the high AD group (p = 0.024). In patients with CSM, preoperative LA ratio of AD is seldom affected by spinal cord compression, and it negatively correlates with JOA recovery rate 6 months after surgery.

Predictive Value of Preoperative Diffusion Tensor Imaging for Evaluating Postoperative Outcomes of Supratentorial Glioma in the Motor Function Area.

This study aimed to assess the predictive value of preoperative diffusion tensor imaging (DTI) data for surgical outcomes of patients with supratentorial glioma in the motor function area. This is a retrospective study of 43 patients receiving navigation-guided surgery for histopathologically demonstrated supratentorial glioma in the motor function area. All patients underwent preoperative 3 Tesla magnetic resonance imaging examinations with conventional and DTI sequences. Data on preoperative imaging and pre- and postoperative clinical characteristics of patients were retrospectively collected. Univariate and multivariate linear regressions were applied to analyze the relationships between preoperative parameters and pre- and postoperative muscle strength and the Karnofsky Performance Status (KPS) score. Fourteen patients had low-grade gliomas and 29 had high-grade gliomas. Although the corticospinal tract (CST) score did not differ significantly between tumor grades, edema and deviation were common in low-grade gliomas (64.3%), while destroyed and infiltrated lesions were common in high-grade gliomas (58.6%). Muscle strength improved after surgery in the deviated tract group (40%) more than in the infiltrated tract group (33.3%). Two independent indices, preoperative muscle strength (p =0.000) and glioma-to-CST distance (p =0.001), were linearly related to postoperative muscle strength. The preoperative KPS score was the only indicator that affected the postoperative KPS score (p =0.000). DTI should be considered in surgical management of supratentorial gliomas in the motor function area to determine the appropriate surgical strategy and predict the nature of the tumor and postoperative motor function.

Preoperative language tract integrity is a limiting factor in recovery from aphasia after glioma surgery

Aphasia can occur in a broad range of pathological conditions that affect cortical or subcortical structures. Here we test the hypothesis that white matter integrity of language pathways assessed by preoperative diffusion tensor imaging (DTI) is associated with language performance and its recovery after glioma resection. 27 patients with preoperative DTI were included. Segmentation of the arcuate fascicle (AF), the inferior fronto-occipital fascicle (IFOF), the inferior longitudinal fascicle (ILF), the superior longitudinal fascicle (SLF), and the uncinate fascicle (UF) was performed with a fully-connected neural network (FCNN, TractSeg). Median fractional anisotropy (FA) was extracted from the resulting volumes as surrogate marker for white matter integrity and tested for correlation with clinical parameters. After correction for demographic data and multiple testing, preoperative white matter integrity of the IFOF, the ILF, and the UF in the left hemisphere were independently and significantly associated with aphasia three months after surgery. Comparison between patients with and without aphasia three months after surgery revealed significant differences in preoperative white matter integrity of the left AF (p = 0.021), left IFOF (p = 0.015), left ILF (p = 0.003), left SLF (p = 0.001, p = 0.021, p = 0.043 for respective sub-bundles 1–3), left UF (p = 0.041) and the right AF (p = 0.027). Preoperative assessment of white matter integrity of the language network by time-efficient MRI protocols and FCNN-driven segmentation may assist in the evaluation of postoperative rehabilitation potential in glioma patients.

STMO-17 USEFULNESS OF INTEGRATION OF PREOPERATIVE FUNCTIONAL IMAGING AND INTRAOPERATIVE MRI NAVIGATION SYSTEM IN GLIOMA SURGERY

Abstract Purpose Intraoperative magnetic resonance imaging (MRI) update navigation is performed in all cases to preserve neurological function and remove the tumor as much as possible, and to prevent recurrence and improve prognosis. And under awake craniotomy, we supported operators by integrating preoperative functional images with intraoperative MRI. We report our usefulness of image superimposition between medium magnetic field intraoperative MRI and preoperative position emission tomography (PET) and preoperative diffusion tensor imaging (DTI) color-map. Method Of more than 2,200 cases using intraoperative MRI since 2000, 58 preoperative PET (57 methionine and 1 FDG nuclides) superimposed cases (32 left-sided, 35 males, 15 under awake craniotomy, mean 44.8 y.o.) were evaluated. The tumor was located to 34 frontal-, 12 temporal-, 10 parietal lobes, 1 insular gyrus, 1 thalamus. Color-map image superimposition of preoperative DTI (3T, 6-axis application) anisotropic indices in 12 cases (localized in 8 frontal-, 2 insular-, 2 parietal lobes, 7 left-sided, 7 females, mean 35 y.o.). Neurophysiological monitoring was combined (5 under general, 7 awake anesthesia). Results The preoperative TN ratio was 3.8 (in 57 methionine-PET cases), and pathological results (Grade 3-4 in 15-31 cases respectively, out of 54 cases) were used for reliable and preferential removal of sites with higher malignancy and recurrence-prone sites. Recurrent cases (41/58) had altered brain structures that were too difficult to identify without the navigation. In the DTI cases, intraoperative MRI, DTI color-map, and microscopic surgical images were displayed on one screen, and white matter tracts information as a reference is quickly conveyed to operators, and helped to reduce perioperative neurological complications. Conclusion Co-registering an effective superimposition of medium magnetic field intraoperative MRI with high positional accuracy, and preoperative PET- and DTI- images according to the patient's characteristics is currently the most practical navigation application method for intraoperative prediction of important functional information.

NCOG-19. TUMOR INVASION INFLUENCES ON COGNITIVE FUNCTION IN RIGHT CEREBRAL HEMISPHERIC GLIOBLASTOMAS

Abstract INTRODUCTION Glioblastoma cells broadly infiltrate into surrounding brain parenchyma. In this study, we investigated the influence of tumor invasion on cognitive function in glioblastomas, using diffusion tensor imaging (DTI) . METHODS Participants were 32 patients with right hemispheric glioblastoma who underwent surgery in Kanazawa University Hospital (mean age, 61.8 years). We evaluated the differences in p-map and q-map, which represent diffusion isotropy and anisotropy with the patients' preoperative DTI. The patients were divided into two groups: less-invasive and highly-invasive types. Following clinical and demographic factors were collected retrospectively: age, sex, volume of enhanced lesion, tumor location, and methylation status of MGMT promoter. Several kinds of cognitive functions mediated by right cerebral hemisphere were assessed preoperatively. All these factors were compared between two groups. Moreover, voxel-based lesion symptom (VLSM) analyses were performed to investigate brain regions relate to decline of cognitive function by tumor invasion. RESULTS All clinical and demographic factors were not significantly different between two groups. Tumor cells significantly infiltrated to insula and basal ganglia in highly-invasive group. Verbal fluency, executive function, attention, and social cognition were impaired in highly-invasive group (p=0.0067, 0.036, 0.0064, and 0.030, respectively). Score of verbal fluency and social cognition were significantly lower when tumor infiltrated to the medial frontal region including cingulate cortex, and deep part of posterior middle and inferior frontal gyrus. Invasion to the sagittal stratum influenced on deterioration of attention and executive function. CONCLUSION The present study revealed that tumor invasion extending beyond the enhanced lesion causes deterioration of cognitive functions such as verbal fluency, executive function, attention, and social cognition in right hemispheric glioblastoma.

Diffusion tensor imaging changes in patients with glioma-associated seizures

IntroductionStructural white matter changes associated with certain epilepsy subtypes have been demonstrated using diffusion tensor imaging (DTI). This observational study aims to identify potential water diffusion abnormalities in glioma patients with associated seizures.MethodsTwo cohorts from two centers were analyzed independently: (A) Prospectively recruited patients diagnosed with glioma who received preoperative DTI to measure mean diffusivity (MD) and fractional anisotropy (FA) in regions-of-interest (ROIs) including the marginal tumor zone (TU), adjacent peritumoral white matter as well as distant ipsilateral and contralateral white matter and cortex. Data were compared between patients with and without seizures and tested for statistical significance. (B) A retrospective cohort using an alternative technical approach sampling ROIs in contrast enhancement, necrosis, non-enhancing tumor, marginal non-enhancing tumor zone, peritumoral tissue, edema and non-tumorous tissue.Results(A) The prospective study cohort consisted of 23 patients with 12 (52.2%) presenting with a history of seizures. There were no significant seizure-associated differences in MD or FA for non-tumor white matter or cortical areas. MD-TU was significantly lower in patients with seizures (p = 0.005). (B) In the retrospective cohort consisting of 46 patients with a seizure incidence of 50.0%, significantly decreased normalized values of MD were observed for non-enhancing tumor regions of non-glioblastoma multiforme (GBM) cases in patients with seizures (p = 0.022).ConclusionDTI analyses in glioma patients demonstrated seizure-associated diffusion restrictions in certain tumor-related areas. No other structural abnormalities in adjacent or distant white matter or cortical regions were detected.

Significance of Preoperative Nerve Reconstruction Using Diffusion Tensor Imaging Tractography for Facial Nerve Protection in Vestibular Schwannoma.

The facial nerve trace on the ipsilateral side of the vestibular schwannoma was reconstructed by diffusion tensor imaging tractography to identify the adjacent relationship between the facial nerve and the tumor, and to improve the level of intraoperative facial nerve protection. The clinical data of 30 cases of unilateral vestibular schwannoma who underwent tumor resection via retrosigmoid approach were collected between January 2019 and December 2020. All cases underwent magnetic resonance imaging examination before operation. Diffusion tensor imaging and anatomical images were used to reconstruct the facial nerve track of the affected side, so as to predict the course of the nerve and its adjacent relationship with the tumor, to compare the actual trace of the facial nerve during operation, verify the degree of coincidence, and evaluate the nerve function (House-Brackmann grade) after surgery. The facial nerve of 27 out of 30 cases could be displayed by diffusion tensor imaging tractography, and the tracking rate was 90% (27/30). The intraoperative locations of facial nerve shown in 25 cases were consistent with the preoperative reconstruction results. The coincidence rate was 92.6% (25/27). The facial nerves were located on the anterior middle part of the tumor in 14 cases, anterior upper part in eight cases, anterior lower part in seven cases, and superior polar in one case. Intraoperative facial nerve anatomy was preserved in 30 cases. Among the 30 patients, total resection was performed in 28 cases and subtotal resection in two cases. The facial nerve function was evaluated 2 weeks after operation, and the results showed grade I in 12 cases, grade II in 16 cases and grade III in two cases. Preoperative diffusion tensor imaging tractography can clearly show the trajectory and adjacent position of the facial nerve on the side of vestibular schwannoma, which is beneficial to accurately identify and effectively protect the facial nerve during the operation, and is worthy of clinical application and promotion.

Can preoperative cervical spinal diffusion tensor imaging (DTI) indices predict surgical outcomes in patients with Hirayama disease? A retrospective cohort study.

ObjectiveAnterior cervical discectomy and fusion (ACDF) surgery can effectively prevent disease progression in patients with Hirayama disease (HD) and diffusion tensor imaging (DTI) can quantitatively assess spinal cord function. In this study, we aimed to evaluate the relationship between preoperative spinal DTI indices and the clinical outcomes of patients with HD when treated by ACDF.MethodsWe retrospectively analyzed 35 HD patients treated by ACDF. We collated a range of DTI indices, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values, prior to surgery with patients in flexion and neutral positions. Patients were divided into improvement (Im) group and non-improvement (Nim) group according to the Odom score, and the difference in surgical outcomes between the two groups was confirmed by quick disabilities of the arm, shoulder and hand (Q-DASH) scores. The DTI indices in the two groups of patients were then compared. Receiver operating characteristic (ROC) curves and area under curve (AUC) were used to evaluate the predictive capability. The correlation between Q-DASH scores and DTI indices was also evaluated.ResultsThe FA values in the two groups of patients differed significantly in the cervical flexion position and the different segments were mainly located in the lower cervical spinal cord including the flexion C5/6 (Im group vs. Nim group: 0.501 ± 0.078 vs. 0.362 ± 0.087, P < 0.001) and C6/7 (Im group vs. Nim group: 0.455 ± 0.097 vs. 0.347 ± 0.102, P = 0.003) FA values, the mean FA value for C4/5-C6/7 (Im group vs. Nim group: 0.471 ± 0.067 vs. 0.372 ± 0.078, P < 0.001), mean FA value for C5/6-C6/7 (Im group vs. Nim group: 0.478 ± 0.076 vs. 0.354 ± 0.083, P < 0.001) and mean FA value for the two minimal segments (Im group vs. Nim group: 0.442 ± 0.078 vs. 0.341 ± 0.081, P = 0.001). The ADC values were similar to FA values. The ROC curve for DTI indices in the lower cervical spinal cord had an AUC > 0.7 including: flexion FA value and ADC value for C5/6 (0.877 and 0.931), flexion FA value and ADC value for C6/7 (0.778 and 0.761), flexion mean FA value and ADC value for C4/5-C6/7 (0.846 and 0.859), flexion mean FA value and ADC value for C5/6-C6/7 (0.861 and 0.905), flexion mean FA value and ADC value for the two minimal/maximal segments (0.815 and 0.892). DTI indices including FA value and ADC value were correlated with the preoperative score, final follow-up score and improvement percentage. Flexion ADC value was correlated with improvement score but flexion FA value was not correlated with improvement score.ConclusionPreoperative DTI indices of the spinal cord, especially those of the lower cervical spinal cord with patients in the flexion position, can predict the clinical outcome of patients with HD post-surgery. In general, a larger FA value and a smaller ADC value indicate a better surgical outcome.