Prognostic value of preoperative dynamic contrast-enhanced MRI perfusion parameters for high-grade glioma patients

INTRODUCTION: The prognostic value of the dynamic contrast-enhanced (DCE) MRI perfusion and its histogram analysis-derived metrics is not well established for high-grade glioma (HGG) patients. The aim of this prospective study was to investigate DCE perfusion transfer coefficient (Ktrans), vascular plasma volume fraction (vp), extracellular volume fraction (ve), reverse transfer constant (kep), and initial area under gadolinium concentration time curve (IAUGC) as predictors of progression-free (PFS) and overall survival (OS) in HGG patients. METHODS: Sixty-nine patients with suspected anaplastic astrocytoma or glioblastoma underwent preoperative DCE-MRI scans. DCE perfusion whole tumor region histogram parameters, clinical details, and PFS and OS data were obtained. Univariate, multivariate, and Kaplan–Meier survival analyses were conducted. Receiver operating characteristic (ROC) curve analysis was employed to identify perfusion parameters with the best differentiation performance. RESULTS: On univariate analysis, ve and skewness of vp had significant negative impacts, while kep had significant positive impact on OS (P < 0.05). ve was also a negative predictor of PFS (P < 0.05). Patients with lower ve and IAUGC had longer median PFS and OS on Kaplan–Meier analysis (P < 0.05). Ktrans and ve could also differentiate grade III from IV gliomas (area under the curve 0.819 and 0.791, respectively). CONCLUSIONS: High ve is a consistent predictor of worse PFS and OS in HGG glioma patients. vp skewness and kep are also predictive for OS. Ktrans and ve demonstrated the best diagnostic performance for differentiating grade III from IV gliomas

THE AFTERCARE SURVEY:Assessment and intervention practices after brain tumour surgery in Europe

Introduction People with gliomas need specialized neurosurgical, neuro-oncological, psycho-oncological, and neuropsychological care. The role of language and cognitive recovery and rehabilitation in patients’ well-being and resumption of work is crucial, but there are no clear guidelines for the ideal timing and character of assessments and interventions. The goal of the present work was to describe representative (neuro)psychological practices implemented after brain surgery in Europe. Methods An online survey was addressed to professionals working with individuals after brain surgery. We inquired about the assessments and interventions and the involvement of caregivers. Additionally, we asked about recommendations for an ideal assessment and intervention plan. Results Thirty-eight European centres completed the survey. Thirty of them offered at least one post-surgical (neuro)psychological assessment, mainly for language and cognition, especially during the early recovery stage and at long-term. Twenty-eight of the participating centres offered post-surgical therapies. Patients who stand the highest chances of being included in evaluation and therapy post-surgically are those who underwent awake brain surgery, harboured a low-grade glioma, or showed poor recovery. Nearly half of the respondents offer support programs to caregivers, and all teams recommend them. Treatments differed between these offered to individuals with low-grade glioma versus those with high-grade glioma. The figure of caregiver is not yet fully recognized in the recovery phase. Conclusion We stress the need for more complete rehabilitation plans, including the emotional and health-related aspects of recovery. In respondents´ opinions, assessment and rehabilitation plans should also be individually tailored and goal-directed (e.g., professional reinsertion)

Transcranial Electrical Stimulation: Methodology and Applications

Low-intensity transcranial current stimulation is a rapidly growing field of research. Transcranial direct current stimulation (tDCS) is the dominant paradigm of this new field, with transcranial alternating current stimulation (tACS) just emerging. Anodal stimulation with tDCS has excitatory effects on the underlying cortex, whereas cathodal stimulation has inhibitory effects. Because both electrodes have significant brain effects when placed at cephalic areas, the term &quot;reference&quot; electrode should be avoided. Most studies have applied tDCS to the motor cortex, the prefrontal cortex, and the occipital cortex. Applications of tDCS include modulation of electrophysiological and hemodynamic brain activity, symptom reduction in neurological and psychiatric pathology, and cognitive improvement in healthy volunteers or clinical populations. There is evidence of motor improvement in patients with stroke, pain reduction in fibromyalgia, improved mood in patients with unipolar or bipolar depression, and reduced craving. Healthy volunteers are shown to improve their verbal fluency, working memory, and implicit learning. Moreover, there are interactions of tDCS with various pharmacological substances. There are no significant side effects, apart from minor skin lesions when tap water is used instead of saline solution in the sponge electrodes. Further research is required to reveal the potential of tACS. © 2011 Copyright Taylor and Francis Group, LLC

Neuropsychological examination detects post-operative complications in idiopathic normal pressure hydrocephalus (iNPH): report of two cases

Subdural fluid collections (SFC) are characteristic complications of shunting for idiopathic normal pressure hydrocephalus (iNPH). This report presents two shunted iNPH patients with clinically silent postoperative SFC, detected after abnormal neuropsychological findings. These cases highlight the value of neuropsychological assessment in the routine postoperative assessment of iNPH. © 2014, © 2014 Taylor &amp; Francis

Motor and language deficits correlate with resting state functional magnetic resonance imaging networks in patients with brain tumors

Background and purpose: Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor. Materials and methods: Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n = 49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n = 29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA). Results: Motor group: paretic patients showed significantly (P = 0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P &lt; 0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r = 0.68, P &lt; 0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P = 0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r = 0.72, P &lt; 0.01) between BA 44 BOLD signal and phonological fluency performance was observed. Conclusions: Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients. © 2018 Elsevier Masson SA

Motor and language deficits correlate with resting state functional magnetic resonance imaging networks in patients with brain tumors

Background and purpose Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor. Materials and methods Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n = 49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n = 29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA). Results Motor group: paretic patients showed significantly (P = 0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P < 0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r = 0.68, P < 0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P = 0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r = 0.72, P < 0.01) between BA 44 BOLD signal and phonological fluency performance was observed. Conclusions Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients

The cerebral isthmus: Fiber tract anatomy, functional significance, and surgical considerations

OBJECTIVE: The cerebral isthmus is the white matter area located between the periinsular sulcus and the lateral ventricle. Studies demonstrating the fiber tract and topographic anatomy of this entity are lacking in current neurosurgical literature. Hence, the authors’ primary aim was to describe the microsurgical white matter anatomy of the cerebral isthmus by using the fiber dissection technique, and they discuss its functional significance. In addition, they sought to investigate its possible surgical utility in approaching lesions located in or adjacent to the lateral ventricle. METHODS: This study was divided into 2 parts and included 30 formalin-fixed cerebral hemispheres, 5 of which were injected with colored silicone. In the first part, 15 uncolored specimens underwent the Klinger’s procedure and were dissected in a lateromedial direction at the level of the superior, inferior, and anterior isthmuses, and 10 were used for coronal and axial cuts. In the second part, the injected specimens were used to investigate the surgical significance of the superior isthmus in accessing the frontal horn of the lateral ventricle. RESULTS: The microsurgical anatomy of the anterior, superior, and inferior cerebral isthmuses was carefully studied and recorded both in terms of topographic and fiber tract anatomy. In addition, the potential role of the proximal part of the superior isthmus as an alternative safe surgical corridor to the anterior part of the lateral ventricle was investigated. CONCLUSIONS: Using the fiber dissection technique along with coronal and axial cuts in cadaveric brain specimens remains a cornerstone in the acquisition of thorough anatomical knowledge of narrow white matter areas such as the cerebral isthmus. The surgical significance of the superior isthmus in approaching the frontal horn of the lateral ventricle is stressed, but further studies must be carried out to elucidate its role in ventricular surgery. ©AANS, 2016

Approaching the atrium through the intraparietal sulcus: Mapping the sulcal morphology and correlating the surgical corridor to underlying fiber tracts

BACKROUND: Although the operative corridor used during the intraparietal transsulcal approach to the atrium has been previously investigated, most anatomical studies focus on its relationship to the optic radiations. OBJECTIVE: To study the intraparietal sulcus (IPS)morphology and to explore the subcortical anatomy with regard to the surgical trajectory used during the intraparietal transsulcal tranventricular approach. METHODS: Twenty-five adult, formalin fixed, cerebral hemispheres were investigated. Fifteen underwent the Klingler procedure and were dissected in a lateromedial direction using the fibermicrodissection technique. The trajectory of the dissection resembled that of real operative settings. The remaining 10 hemispheres were cut along the longitudinal axis of the sulcus in order to correlate its surface anatomy to corresponding parts of the ventricular system. RESULTS: IPS demonstrated an interrupted course in 36% of the specimens while its branching pattern was variable. The sulcus anterior half was found to overly the atrium in all occasions. Four discrete, consecutivewhite matter layerswere identified en route to the atrium, ie, the arcuate fibers, the arcuate segment of the superior longitudinal fasciculus, the corona radiata and tapetum, with the arcuate segment being near to the dissection trajectory. CONCLUSION: Given the angle of brain transgression during the intraparietal approach, we found the optimal dissection area to be the very middle of the sulcus. The IPS- postcentral sulcus meeting point, in contrast to previous thought, proved to risk potential injury to the arcuate segment of the superior longitudinal fasciculus, thus affecting surgical outcome. © 2017 by the Congress of Neurological Surgeons

Prognostic value of preoperative dynamic contrast-enhanced MRI perfusion parameters for high-grade glioma patients

Introduction: The prognostic value of the dynamic contrast-enhanced (DCE) MRI perfusion and its histogram analysis-derived metrics is not well established for high-grade glioma (HGG) patients. The aim of this prospective study was to investigate DCE perfusion transfer coefficient (Ktrans), vascular plasma volume fraction (vp), extracellular volume fraction (ve), reverse transfer constant (kep), and initial area under gadolinium concentration time curve (IAUGC) as predictors of progression-free (PFS) and overall survival (OS) in HGG patients. Methods: Sixty-nine patients with suspected anaplastic astrocytoma or glioblastoma underwent preoperative DCE-MRI scans. DCE perfusion whole tumor region histogram parameters, clinical details, and PFS and OS data were obtained. Univariate, multivariate, and Kaplan–Meier survival analyses were conducted. Receiver operating characteristic (ROC) curve analysis was employed to identify perfusion parameters with the best differentiation performance. Results: On univariate analysis, ve and skewness of vp had significant negative impacts, while kep had significant positive impact on OS (P &amp;lt; 0.05). ve was also a negative predictor of PFS (P &amp;lt; 0.05). Patients with lower ve and IAUGC had longer median PFS and OS on Kaplan–Meier analysis (P &amp;lt; 0.05). Ktrans and ve could also differentiate grade III from IV gliomas (area under the curve 0.819 and 0.791, respectively). Conclusions: High ve is a consistent predictor of worse PFS and OS in HGG glioma patients. vp skewness and kep are also predictive for OS. Ktrans and ve demonstrated the best diagnostic performance for differentiating grade III from IV gliomas. © 2016, The Author(s)

Transcranial alternating current stimulation reduces symptoms in intractable idiopathic cervical dystonia: A case study

Idiopathic cervical dystonia (ICD) is a movement disorder often resulting in profound disability and pain. Treatment options include oral medications or other invasive procedures, whereas intractable ICD has been shown to respond to invasive (deep) brain stimulation. In the present blinded, placebo-controlled case study, transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) has been applied to a 54-year old patient with intractable ICD. Results showed that 15. Hz tACS had both immediate and cumulative effects in dystonic symptom reduction, with a 54% reduction in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score, and a 75% in the TWSTRS Pain Scale. These effects were persistent at 30-days follow-up. This is the first report to demonstrate a significant and lasting therapeutic effect of non-invasive electrical brain stimulation in dystonia. © 2012 Elsevier Ireland Ltd