scholarly journals Endoscopic Endonasal Transclival Approach to the Ventral Brainstem: Anatomic Study of the Safe Entry Zones Combining Fiber Dissection Technique with 7 Tesla Magnetic Resonance Guided Neuronavigation

2018 ◽  
Vol 15 (4) ◽  
pp. 480-480
Keyword(s):  
Magnetic Resonance ◽  
7 Tesla ◽  
Anatomic Study ◽  
Endoscopic Endonasal ◽  
Fiber Dissection ◽  
Dissection Technique

scholarly journals Endoscopic Endonasal Transclival Approach to the Ventral Brainstem: Anatomic Study of the Safe Entry Zones Combining Fiber Dissection Technique with 7 Tesla Magnetic Resonance Guided Neuronavigation

2018 ◽  
Vol 16 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Alessandro Weiss ◽  
Paolo Perrini ◽  
Matteo De Notaris ◽  
Guadalupe Soria ◽  
Alarcon Carlos ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
High Resolution ◽  
7 Tesla ◽  
Superior Cerebellar Artery ◽  
Endoscopic Endonasal ◽  
Close Relationship ◽  
Fresh Frozen ◽  
Fiber Dissection ◽  
Dissection Technique ◽  
Brainstem Anatomy

Abstract BACKGROUND Treatment of intrinsic lesions of the ventral brainstem is a surgical challenge that requires complex skull base antero- and posterolateral approaches. More recently, endoscopic endonasal transclival approach (EETA) has been reported in the treatment of selected ventral brainstem lesions. OBJECTIVE In this study we explored the endoscopic ventral brainstem anatomy with the aim to describe the degree of exposure of the ventral safe entry zones. In addition, we used a newly developed method combining traditional white matter dissection with high-resolution 7T magnetic resonance imaging (MRI) of the same specimen coregistered using a neuronavigation system. METHODS Eight fresh-frozen latex-injected cadaver heads underwent EETA. Additional 8 formalin-fixed brainstems were dissected using Klingler technique guided by ultra-high resolution MRI. RESULTS The EETA allows a wide exposure of different safe entry zones located on the ventral brainstem: the exposure of perioculomotor zone requires pituitary transposition and can be hindered by superior cerebellar artery. The peritrigeminal zone was barely visible and its exposure required an extradural anterior petrosectomy. The anterolateral sulcus of the medulla was visible in most of specimens, although its close relationship with the corticospinal tract makes it suboptimal as an entry point for intrinsic lesions. In all cases, the use of 7T-MRI allowed the identification of tiny fiber bundles, improving the quality of the dissection. CONCLUSION Exposure of the ventral brainstem with EETA requires mastering surgical maneuvers, including pituitary transposition and extradural petrosectomy. The correlation of fiber dissection with 7T-MRI neuronavigation significantly improves the understanding of the brainstem anatomy.

Anatomic Study of the Central Core of the Cerebrum Correlating 7-T Magnetic Resonance Imaging and Fiber Dissection With the Aid of a Neuronavigation System

2013 ◽  
Vol 10 (2) ◽  
pp. 294-304 ◽  
Author(s):  
Carlos Alarcon ◽  
Matteo de Notaris ◽  
Kenneth Palma ◽  
Guadalupe Soria ◽  
Alessandro Weiss ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Ex Vivo ◽  
Central Core ◽  
Resonance Imaging ◽  
Anatomic Study ◽  
Neuronavigation System ◽  
Fiber Dissection ◽  
Dissection Technique

Abstract BACKGROUND: Different strategies have been used to study the fiber tract anatomy of the human brain in vivo and ex vivo. Nevertheless, the ideal method to study white matter anatomy has yet to be determined because it should integrate information obtained from multiple sources. OBJECTIVE: We developed an anatomic method in cadaveric specimens to study the central core of the cerebrum combining traditional white matter dissection with high-resolution 7-T magnetic resonance imaging (MRI) of the same specimen coregistered using a neuronavigation system. METHODS: Ten cerebral hemispheres were prepared using the traditional Klingler technique. Before dissection, a structural ultrahigh magnetic field 7-T MRI study was performed on each hemisphere specifically prepared with surface fiducials for neuronavigation. The dissection was then performed from the medial hemispheric surface using the classic white fiber dissection technique. During each step of the dissection, the correlation between the anatomic findings and the 7-T MRI was evaluated with the neuronavigation system. RESULTS: The anatomic study was divided in 2 stages: diencephalic and limbic. The diencephalic stage included epithalamic, thalamic, hypothalamic, and subthalamic components. The limbic stage consisted of extending the dissection to complete the Papez circuit. The detailed information given by the combination of both methods allowed us to identify and validate the position of fibers that may be difficult to appreciate and dissect (ie, the medial forebrain bundle). CONCLUSION: The correlation of high-definition 7-T MRI and the white matter dissection technique with neuronavigation significantly improves the understanding of the structural connections in complex areas of the human cerebrum.

Posterior Quadrant Disconnection: A Fiber Dissection Study

2017 ◽  
Vol 14 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Alexander Verhaeghe ◽  
Thomas Decramer ◽  
Wim Naets ◽  
Wim Van Paesschen ◽  
Johannes van Loon ◽  
...  
Keyword(s):  
White Matter ◽  
Corpus Callosum ◽  
Anatomic Study ◽  
Posterior Cortex ◽  
Optimal Outcomes ◽  
Posterior Quadrant ◽  
Fiber Dissection ◽  
Temporal Stem ◽  
Dissection Technique ◽  
The Brain

AbstractBACKGROUNDPosterior quadrant disconnection can be highly effective in the surgical treatment of selected cases of refractory epilepsy. The technique aims to deafferent extensive areas of epileptogenic posterior cortex from the rest of the brain by isolating the temporoparietooccipital cortex.OBJECTIVETo describe this procedure and relevant white matter tracts with a specific emphasis on the extent of callosotomy in an anatomic study.METHODSTwenty hemispheres were dissected according to Klingler's fiber dissection technique illustrating the peri-insular (temporal stem, superior longitudinal fasciculus, corona radiata) and mesial disconnection (mesiotemporal cortex, cingulum, and corpus callosum).RESULTSExtensive white matter tract disconnection is obtained after posterior quadrant disconnection. Callosal fibers connecting the anterior most part of the parietal cortex invariably ran through the isthmus of the corpus callosum and need to be disconnected, while frontal lobe connections including the corticospinal tract and the anterior two-thirds of the corpus callosum are spared during the procedure.CONCLUSIONOur findings suggest the involvement of both the splenium and the isthmus in interhemispheric propagation in posterior cortex epilepsies. Sectioning the total extent of the posterior one-third of the corpus callosum might therefore be necessary to achieve optimal outcomes in posterior quadrant epilepsy surgery.

scholarly journals Alteration within the Hippocampal Volume in Patients with LHON Disease—7 Tesla MRI Study

2020 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
Cezary Grochowski ◽  
Kamil Jonak ◽  
Marcin Maciejewski ◽  
Andrzej Stępniewski ◽  
Mansur Rahnama-Hezavah
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Molecular Layer ◽  
Three Dimensional ◽  
Hippocampal Volume ◽  
7 Tesla ◽  
Diagnostic Process ◽  
Resonance Imaging ◽  
The Right

Purpose: The aim of this study was to assess the volumetry of the hippocampus in the Leber’s hereditary optic neuropathy (LHON) of blind patients. Methods: A total of 25 patients with LHON were randomly included into the study from the national health database. A total of 15 patients were selected according to the inclusion criteria. The submillimeter segmentation of the hippocampus was based on three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) BRAVO 7T magnetic resonance imaging (MRI) protocol. Results: Statistical analysis revealed that compared to healthy controls (HC), LHON subjects had multiple significant differences only in the right hippocampus, including a significantly higher volume of hippocampal tail (p = 0.009), subiculum body (p = 0.018), CA1 body (p = 0.002), hippocampal fissure (p = 0.046), molecular layer hippocampus (HP) body (p = 0.014), CA3 body (p = 0.006), Granule Cell (GC) and Molecular Layer (ML) of the Dentate Gyrus (DG)–GC ML DG body (p = 0.003), CA4 body (p = 0.001), whole hippocampal body (p = 0.018), and the whole hippocampus volume (p = 0.023). Discussion: The ultra-high-field magnetic resonance imaging allowed hippocampus quality visualization and analysis, serving as a powerful in vivo diagnostic tool in the diagnostic process and LHON disease course assessment. The study confirmed previous reports regarding volumetry of hippocampus in blind individuals.

scholarly journals Prefrontal and hippocampal atrophy using 7-tesla magnetic resonance imaging in patients with Parkinson’s disease

2021 ◽  
Vol 10 (2) ◽  
pp. 205846012098809
Author(s):  
Byeong H Oh ◽  
Hyeong C Moon ◽  
Aryun Kim ◽  
Hyeon J Kim ◽  
Chae J Cheong ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Magnetic Resonance ◽  
7 Tesla ◽  
Cortical Atrophy ◽  
Automated Segmentation ◽  
Healthy Controls ◽  
Segmentation Method ◽  
Resonance Imaging

Background The pathology of Parkinson’s disease leads to morphological changes in brain structure. Currently, the progressive changes in gray matter volume that occur with time and are specific to patients with Parkinson’s disease, compared to healthy controls, remain unclear. High-tesla magnetic resonance imaging might be useful in differentiating neurological disorders by brain cortical changes. Purpose We aimed to investigate patterns in gray matter changes in patients with Parkinson’s disease by using an automated segmentation method with 7-tesla magnetic resonance imaging. Material and Methods High-resolution T1-weighted 7 tesla magnetic resonance imaging volumes of 24 hemispheres were acquired from 12 Parkinson’s disease patients and 12 age- and sex-matched healthy controls with median ages of 64.5 (range, 41–82) years and 60.5 (range, 25–74) years, respectively. Subgroup analysis was performed according to whether axial motor symptoms were present in the Parkinson’s disease patients. Cortical volume, cortical thickness, and subcortical volume were measured using a high-resolution image processing technique based on the Desikan-Killiany-Tourville atlas and an automated segmentation method (FreeSurfer version 6.0). Results After cortical reconstruction, in 7 tesla magnetic resonance imaging volume segmental analysis, compared with the healthy controls, the Parkinson’s disease patients showed global cortical atrophy, mostly in the prefrontal area (rostral middle frontal, superior frontal, inferior parietal lobule, medial orbitofrontal, rostral anterior cingulate area), and subcortical volume atrophy in limbic/paralimbic areas (fusiform, hippocampus, amygdala). Conclusion We first demonstrated that 7 tesla magnetic resonance imaging detects structural abnormalities in Parkinson’s disease patients compared to healthy controls using an automated segmentation method. Compared with the healthy controls, the Parkinson’s disease patients showed global prefrontal cortical atrophy and hippocampal area atrophy.

scholarly journals Implantable NMR Microcoils in Rats: A New Tool for Exploring Tumor Metabolism at Sub-Microliter Scale?

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 176
Author(s):  
Justine Deborne ◽  
Noël Pinaud ◽  
Yannick Crémillieux
Keyword(s):  
Magnetic Resonance ◽  
Tumor Model ◽  
Surface Coil ◽  
Regions Of Interest ◽  
7 Tesla ◽  
Resonance Spectroscopy ◽  
Volume Coil ◽  
Detection Volume ◽  
The Right

The aim of this study was to evaluate the potential of a miniaturized implantable nuclear magnetic resonance (NMR) coil to acquire in vivo proton NMR spectra in sub-microliter regions of interest and to obtain metabolic information using magnetic resonance spectroscopy (MRS) in these small volumes. For this purpose, the NMR microcoils were implanted in the right cortex of healthy rats and in C6 glioma-bearing rats. The dimensions of the microcoil were 450 micrometers wide and 3 mm long. The MRS acquisitions were performed at 7 Tesla using volume coil for RF excitation and microcoil for signal reception. The detection volume of the microcoil was measured equal to 450 nL. A gain in sensitivity equal to 76 was found in favor of implanted microcoil as compared to external surface coil. Nine resonances from metabolites were assigned in the spectra acquired in healthy rats (n = 5) and in glioma-bearing rat (n = 1). The differences in relative amplitude of choline, lactate and creatine resonances observed in glioma-bearing animal were in agreement with published findings on this tumor model. In conclusion, the designed implantable microcoil is suitable for in vivo MRS and can be used for probing the metabolism in localized and very small regions of interest in a tumor.

Sign in / Sign up

Export Citation Format

Share Document