Quantification of white matter fibre pathways disruption in frontal transcortical approach to the lateral ventricle or the interventricular foramen in diffusion tensor tractography

Pathologies occupying the interventricular foramen (foramen of Monro — FM) or the anterior part of lateral ventricle (LV) are accessed by the transcortical or transcallosal route. As severing of rostral corpus callosum has been deemed inferior to cortical incision, the approaches through various points of frontal lobe have been developed. Superior (F1), middle (F2) frontal gyrus or occasionally superior frontal sulcus are used as an entry of neurosurgical corridor. In spite of the fact that every approach to LV or FM causes its characteristic irreversible damage to white matter, to date all of transcortical routes are regarded as equivalent. The current study compared the damage of main neural bundles between virtualtrans-F1 and trans-F2 corridors by means of diffusion tensor tractography method (DTT) in 11 magnetic resonance imaging (MRI) exams from clinical series (22 hemispheres, regardless of dominance). Corpus callosum, cingulum, subdivisions I and II of superior longitudinal fasciculus (SLF I and SLF II), corticoreticular as well as pyramidal tracts crossing both approaches were subjected to surgical violation. Both approaches served a similar total number of fibres (0.94 to 1.78 [× 103]).Trans-F1 route caused significantly greater damage of total white matter volume(F1: 8.26 vs. F2: 7.16 mL), percentage of SLF I fibres (F1: 78.6% vs. F2: 28.6%)and cingulum (F1: 49.4% vs. F2: 10.6%), whereas trans-F2 route interrupted morecorticoreticular fibres (F1: 4.5% vs. F2: 30.7%). Pyramidal tract (F1: 0.6% vs. F2:1.3%) and SLF II (F1: 15.9% vs. F2: 26.2%) were marginally more vulnerable incase of the access via middle frontal gyrus. Both approaches destroyed 7% of callosal fibres. Summarising the above DTT findings, trans-F2 route disrupted a greater number of fibres from eloquent neural bundles (SLF II, pyramidal and corticoreticular tracts), therefore is regarded as inferior to trans-F1 one. Due to lack of up-to-date guidelines with recommendations of the approaches to LV or FM, an individual preoperative planning based on DTT should precede a surgery

Diffusion tensor tractography imaging in pediatric epilepsy – A systematic review

Purpose Recent years brought several experimental and clinical reports applying diffusion tensor tractography imaging (DTI) of the brain in epilepsy. This study was aimed to evaluate current evidence for adding the DTI sequence to the standard diagnostic magnetic resonance imaging (MRI) protocol in pediatric epilepsy. Material and methods Rapid and qualitative systematic review (RAE, Rapid Evidence Assessment), aggregating relevant studies from the recent 7 years. The PubMed database was hand searched for records containing terms “tractography AND epilepsy.” Only studies referring to children were included; studies were rated using “final quality of evidence.” Results Out of 144 screened records, relevant 101 were aggregated and reviewed. The synthesis was based on 73 studies. Case-control clinical studies were the majority of the material and comprised 43.8% of the material. Low ‘confirmability’ and low ‘applicability’ referred to 18 and 17 articles (29.5% and 27.9%), respectively. The sufficient quality of evidence supported performing DTI in temporal lobe epilepsy, malformations of cortical development and prior to a neurosurgery of epilepsy. Conclusions The qualitative RAE provides an interim estimate of the clinical relevance of quickly developing diagnostic methods. Based on the critical appraisal of current knowledge, adding the DTI sequence to the standard MRI protocol may be clinically beneficial in selected patient groups with childhood temporal lobe epilepsy or as a part of planning for an epilepsy surgery

Dural adhesion as a cause of late clip slippage from the medial cerebral artery aneurysm

Background: A properly placed clip may slip off the aneurysm during the postoperative period. Many factors have been attributed to this complication, although clip adherence to the dural stitch has not been reported. Materials and methods: Following the single occurrence of such unusual complication, 64 similar medial cerebral artery (MCA) aneurysms were retrospectively investigated at a single institution. Clip adherence to the dura demonstrated in early postoperative computed tomography (CT) was a presumed factor of a late clip migration in this study. Results: In the series, there were 4 (6.3%) aneurysm remnants and 1 slipped clip that firmly adhered to the dura. In this particular case, the revision surgery revealed the spring coil firmly adhering to the dura in the previous suture line. Neither the occurrence of an aneurysm neck remnant nor clip slippage were related to the clip’s adherence to the dura in the analysis of the entire group (p > 0.05). On the contrary, application of a fenestrated clip did contribute to that finding in multivariate analysis (p < 0.01). Unlike the rest, two surgeons unintentionally tended to position the clip close to the dura (p < 0.01). The clip-to-dura distance measured in the follow-up CT angiography 1 year after the surgery differed from that in the postoperative CT in 83.8% of the cases and decreased by an average of 0.5 mm. Conclusions: Clip-to-dura adherence should be regarded as a normal finding in the postoperative CT following MCA aneurysm clipping. Surgeons should consider the possibility of clip head protrusion into the dural stitch line

Comparison of colour difference formulas to best distinguish resected areas of malignant brain tumours from their background using 5-aminolevulinic acid fluorescence

Background: Fluorescence-guided surgery (FGS) with 5-aminolevulinic acid (5-ALA) has been proven to assist neurosurgeons to achieve a more complete brain tumour resection. However, 5-ALA-guided surgery is limited since it is often difficult to distinguish the colour difference between the resected areas of malignant brain tumours from their background. Our aim was to evaluate which colour difference formula was optimal to distinguish between malignant brain tumours and the background healthy tissue using 5-ALA fluorescence. Materials and methods: Thirty-seven patients with a primary or secondary malignant brain tumour ingested 5-ALA before the surgery. A 400 nm light was used to excite the fluorescence. Surgical videos were recorded for all the patients and a total of 183 samples were obtained from the fluorescent areas and their respective backgrounds. Three colour differences formulas — contrast ratio (CR), CIELab (ΔE*) and CIEDE2000 — were applied to the videos and compared using hot-cold maps. Baseline demographics, the tumour’s location, the tumour’s side, and tumour’s World Health Organization (WHO) grade was also analysed for correlations relating to the fluorescence. Chi-square and the Student’s t-test were used for univariate relations. The three channels of the CIELAB colour space (L*, a* and b*) were analysed together and separately (since L* of fluorescent areas was significantly higher than the background). Results: ΔE* resulted in good discrimination of a* and b*, and moderate but acceptable discrimination of L*. CIEDE2000 distinguished differences in a* and b*, although not in L*. The CR distinguished only L*, whereas the probability of discriminating a* and b* channels failed. Neither age, sex, tumour location, tumour size nor the WHO grade influenced the a*, b* and L* colour values (p > 0.05). Colour differences measured by ΔE* and CIEDE2000 correlated together (r = 0.99, p < 0.01), whereas CR correlated only with ΔE* (r = 0.21, p = 0.01) but not with CIEDE2000 (r = 0.07, p = 0.32). Conclusions: ΔE* obtained the best colour discrimination between the resected areas of malignant brain tumours and the background when compared to CR and CIEDE2000. Therefore, ΔE* may be the best formula to help neurosurgeons distinguish the colour differences when operating malignant brain tumours with 5-ALA fluorescence

Future of the nerve fibres imaging: tractography application and development directions

Tractography is a tool available in a growing number of centres, to enable planning of neurosurgical interventions. This method has some drawbacks and due to its increasing availability is causing a growing controversy over the possibility of an anatomical mapping of the nerve fibres. This article aims at summarising the application of the diffusion magnetic resonance in contemporary neurosurgery method, showing the usefulness and merits of its performance before surgical procedures, limitation of its application and recommendations for its improvement and more effective use for diagnostic purposes

New corporate law imperativeness and dispositivity

Název, abstrakt a klíčová slova v českém jazyce Kogentnost a dispozitivnost nového práva obchodních společností Abstrakt Disertační práce vychází ze základní premisy, že stěžejní zásadou soukromého práva je autonomie vůle, právo obchodních společností nevyjímaje. Proto pokud má být předmětem zkoumání kogentnost a dispozitivnost práva obchodních společností, musí být zkoumáno to, jakým způsobem se v právu obchodních společností projevuje autonomie vůle a jak je omezována. Veškerá omezení autonomie vůle disponovat se svým soukromoprávním vztahem jsou realizována prostřednictvím určitých limitů, stanovujících hranice, které subjekty právního vztahu nemůžou svým jednáním překročit. V práci je proto provedena kategorizace druhů omezení autonomie vůle a limitů, skrze které se druhy omezení autonomie vůle v právu obchodních společností realizují. Zkoumání limitů autonomie vůle vede v práci k dílčímu závěru, že všechny jejich kategorie lze podřadit pod obecný požadavek, aby právní jednání bylo v souladu se smyslem a účelem zákona. Smysl a účel právní normy proto lze považovat za základní kritérium pro identifikaci právní normy jakožto kogentní nebo dispozitivní. Nutno však zdůraznit, že autonomii vůle neomezují jen kogentní normy, ale i normy dispozitivní. Limity autonomie vůle se neprojevují pouze ve formě...Název, abstrakt a klíčová slova v anlickém jazyce New corporate law imperativeness and dispositivity Abstract This dissertation thesis focuses on the basic premise that the autonomy of the will, as a fundamental principle of private law, also applies to corporate law. When researching the imperative and dispositive norms of corporate law, one must examine how the autonomy of the will can be manifested and limited. All the limitations of the autonomy of the will to dispose of its private-law relations are realised through certain limits, which set boundaries that cannot be overstepped by the subjects of legal relations. Therefore, this paper contains the categorisation of the types of restrictions on the autonomy of the wills and the limits through which these types of restrictions on the autonomy of the will are realised. Exploring the limits of the autonomy of the will leads to a preliminary conclusion that all these categories follow a general requirement, that the legal actions should be in accordance with the meaning and purpose of law. The meaning and purpose of a legal norm can be considered as a basic criterion for defining the legal norm as imperative or dispositive. However, it must be emphasised that the limits on the autonomy of the will may be imposed not only by imperative norms, but also by...Katedra obchodního právaDepartment of Business LawFaculty of LawPrávnická fakult

Frontal aslant tract projections to the inferior frontal gyrus

Background: Frontal aslant tract (FAT) is a white matter bundle connecting the pre-supplementary motor area (pre-SMA) and the supplementary motor area (SMA) with the inferior frontal gyrus (IFG). The purpose of the present study was to evaluate the anatomical variability of FAT. Materials and methods: Total number of fibres and the lateralisation index (LI) were calculated. We attempted to find factors contributing to the diversity of FAT regarding IFG terminations to the pars opercularis (IFG-Op) and to the pars triangularis (IFG-Tr). Magnetic resonance imaging of adult patients with diffusion tensor imaging (DTI) with total number of 98 hemispheres composed a cohort. V-shaped operculum was the most common (60.5%). Results: Total number of FAT fibres had widespread and unimodal distribution (6 to 1765; median: 160). Left lateralisation was noted in 64.3% of cases and was positively correlated with total number of FAT fibres and the bundle projecting to IFG-Op (p < 0.01). LI correlated with total number of FAT fibres (r = 0.43, p < 0.01). FAT projected predominantly to IFG-Op (88.9%; 88 of 99). Only in 3 (3.1%) cases more fibres terminated in IFG-Tr than in IFG-Op. Total number of FAT fibres and number of fibres terminating at IFG-Op did not correlate with the ratio of fibre numbers: FAT/IFG-Op, FAT/IFG-Tr and IFG-Op/IFG-Tr (p > 0.05). The greater total number of fibres to IFG-Tr was, the higher were the ratios of IFG-Tr/ /FAT (r = 0.57, p < 0.01) and IFG-Tr/IFG-Op (r = 0.32, p = 0.04). Conclusions: Among the IFG, the major termination of FAT is IFG-Op. Whereas the IFG-Tr projection seems to be related to the expansion of the entire FAT bundle regardless of side, domination and handedness. Nevertheless, FAT features a significant anatomical variability which cannot be explained in terms of DTI findings