scholarly journals Full-field MRI measurements of in-vivo positional brain shift reveal the significance of intra-cranial geometry and head orientation for stereotactic surgery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefano Zappalá ◽  
Nicholas J. Bennion ◽  
Matthew R. Potts ◽  
Jing Wu ◽  
Slawomir Kusmia ◽  
...  
Keyword(s):  
Shape Change ◽  
Statistical Significance ◽  
Head Tilt ◽  
Head Orientation ◽  
Brain Shift ◽  
Significant Discrepancy ◽  
Complex Deformation ◽  
Full Field ◽  
Reference Space

AbstractPositional brain shift (PBS), the sagging of the brain under the effect of gravity, is comparable in magnitude to the margin of error for the success of stereotactic interventions ($$\sim $$ ∼  1 mm). This non-uniform shift due to slight differences in head orientation can lead to a significant discrepancy between the planned and the actual location of surgical targets. Accurate in-vivo measurements of this complex deformation are critical for the design and validation of an appropriate compensation to integrate into neuronavigational systems. PBS arising from prone-to-supine change of head orientation was measured with magnetic resonance imaging on 11 young adults. The full-field displacement was extracted on a voxel-basis via digital volume correlation and analysed in a standard reference space. Results showed the need for target-specific correction of surgical targets, as a significant displacement ranging from 0.52 to 0.77 mm was measured at surgically relevant structures. Strain analysis further revealed local variability in compressibility: anterior regions showed expansion (both volume and shape change), whereas posterior regions showed small compression, mostly dominated by shape change. Finally, analysis of correlation demonstrated the potential for further patient- and intervention-specific adjustments, as intra-cranial breadth and head tilt correlated with PBS reaching statistical significance.

scholarly journals Full-field MRIMeasurements of in-vivo Positional Brain Shift Reveal the Significance of Intra-cranial Geometry and Head Orientation for Stereotactic Surgery

2021 ◽  
Author(s):  
Stefano Zappalà ◽  
Nicholas J. Bennion ◽  
Matthew R. Potts ◽  
Jing Wu ◽  
Slawomir Kusmia ◽  
...  
Keyword(s):  
Shape Change ◽  
Statistical Significance ◽  
Head Tilt ◽  
Head Orientation ◽  
Brain Shift ◽  
Significant Discrepancy ◽  
Complex Deformation ◽  
Full Field ◽  
Reference Space

Abstract Positional brain shift (PBS), the sagging of the brain under the effect of gravity, is comparable in magnitude to the margin of error for the success of stereotactic interventions (∼1 mm). This non-uniform shift due to slight differences in head orientation can lead to a significant discrepancy between the planned and the actual location of surgical targets. Accurate in vivo measurements of this complex deformation are critical for the design and validation of an appropriate compensation to integrate into neuronavigational systems. PBS arising from prone-to-supine change of head orientation was measured with magnetic resonance imaging on 11 young adults. The full-field displacement was extracted on a voxel-basis via digital volume correlation and analysed in a standard reference space. Results showed the need for target-specific correction of surgical targets, as a significant displacement ranging from 0.52 mm to 0.77 mm was measured at surgically relevant structures. Strain analysis further revealed local variability in compressibility: anterior regions showed expansion (both volume and shape change), whereas posterior regions showed small compression, mostly dominated by shape change. Finally, analysis of correlation demonstrated the potential for further patient-and intervention-specific adjustments, as intra-cranial breadth and head tilt correlated with PBS reaching statistical significance.

Adenosine Diphosphate (ADP)-Induced ⍺-Granules Release from Platelets of Native Whole Blood Is Reduced by Ticlopidine but Not by Aspirin or Dipyridamole

1986 ◽  
Vol 56 (02) ◽  
pp. 147-150 ◽  
Author(s):  
V Pengo ◽  
M Boschello ◽  
A Marzari ◽  
M Baca ◽  
L Schivazappa ◽  
...  
Keyword(s):  
Whole Blood ◽  
Light Transmission ◽  
Ex Vivo ◽  
Early Stage ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Dose Dependent ◽  
Plateletderived Growth Factor ◽  
Platelet Shape

SummaryA brief contact between native whole blood and ADP promotes a dose-dependent release of platelet a-granules without a fall in the platelet number. We assessed the “ex vivo” effect of three widely used antiplatelet drugs, aspirin dipyridamole and ticlopidine, on this system. Aspirin (a single 800 mg dose) and dipyridamole (300 mg/die for four days) had no effect, while ticlopidine (500 mg/die for four days) significantly reduced the a-granules release for an ADP stimulation of 0.4 (p <0.02), 1.2 (p <0.01) and 2 pM (p <0.01). No drug, however, completeley inhibits this early stage of platelet activation. The platelet release of α-granules may be related to platelet shape change of the light transmission aggregometer and may be important “in vivo” by enhancing platelet adhesiveness and by liberating the plateletderived growth factor.

scholarly journals Whole-brain 3D MR fingerprinting brain imaging: clinical validation and feasibility to patients with meningioma

2021 ◽  
Author(s):  
Thomaz R. Mostardeiro ◽  
Ananya Panda ◽  
Robert J. Witte ◽  
Norbert G. Campeau ◽  
Kiaran P. McGee ◽  
...  
Keyword(s):  
White Matter ◽  
Statistical Significance ◽  
Relaxation Times ◽  
Brain Structures ◽  
Centrum Semiovale ◽  
In Vivo Evaluation ◽  
Whole Brain ◽  
Mean Values ◽  
Caudate Head

Abstract Purpose MR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma. Materials and methods A whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman’s ANOVA test. Results MR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001) Conclusions Phantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.

scholarly journals Compensation mechanism in tumor cell migration

2003 ◽  
Vol 160 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Katarina Wolf ◽  
Irina Mazo ◽  
Harry Leung ◽  
Katharina Engelke ◽  
Ulrich H. von Andrian ◽  
...  
Keyword(s):  
Cell Migration ◽  
Tumor Cell ◽  
Shape Change ◽  
Proteolytic Degradation ◽  
Amoeboid Movement ◽  
Tumor Cell Migration ◽  
Tumor Dissemination ◽  
Β1 Integrins

Invasive tumor dissemination in vitro and in vivo involves the proteolytic degradation of ECM barriers. This process, however, is only incompletely attenuated by protease inhibitor–based treatment, suggesting the existence of migratory compensation strategies. In three-dimensional collagen matrices, spindle-shaped proteolytically potent HT-1080 fibrosarcoma and MDA-MB-231 carcinoma cells exhibited a constitutive mesenchymal-type movement including the coclustering of β1 integrins and MT1–matrix metalloproteinase (MMP) at fiber bindings sites and the generation of tube-like proteolytic degradation tracks. Near-total inhibition of MMPs, serine proteases, cathepsins, and other proteases, however, induced a conversion toward spherical morphology at near undiminished migration rates. Sustained protease-independent migration resulted from a flexible amoeba-like shape change, i.e., propulsive squeezing through preexisting matrix gaps and formation of constriction rings in the absence of matrix degradation, concomitant loss of clustered β1 integrins and MT1-MMP from fiber binding sites, and a diffuse cortical distribution of the actin cytoskeleton. Acquisition of protease-independent amoeboid dissemination was confirmed for HT-1080 cells injected into the mouse dermis monitored by intravital multiphoton microscopy. In conclusion, the transition from proteolytic mesenchymal toward nonproteolytic amoeboid movement highlights a supramolecular plasticity mechanism in cell migration and further represents a putative escape mechanism in tumor cell dissemination after abrogation of pericellular proteolysis.

Residual-limb shape change: three-dimensional CT scan measurement and depiction in vivo.

Radiology ◽  
1996 ◽  
Vol 200 (3) ◽  
pp. 843-850 ◽  
Author(s):  
K E Smith ◽  
P K Commean ◽  
M W Vannier
Keyword(s):  
Ct Scan ◽  
Shape Change ◽  
Three Dimensional ◽  
Residual Limb

scholarly journals Bone Regeneration by Novel Bioactive Glasses Containing Strontium and/or Magnesium: A Preliminary In-Vivo Study

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2223 ◽  
Author(s):  
Devis Bellucci ◽  
Valeria Cannillo ◽  
Alexandre Anesi ◽  
Roberta Salvatori ◽  
Luigi Chiarini ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Formation Processes ◽  
Complete Dissolution ◽  
In Vitro Bioactivity ◽  
Bioactive Glasses ◽  
Beneficial Effects ◽  
Glass Dissolution

In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits’ femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal–Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting.

scholarly journals A novel long non-coding RNA GK-IT1 promotes the carcinogenesis and progression of esophageal squamous cell carcinoma via mediating the phosphorylation of MAPK1

2020 ◽  
Author(s):  
Xin Yang ◽  
Tian Yang Zeng ◽  
Zi Yang Liu ◽  
Wan Lun He ◽  
Meng Ting Hu ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Mapk Pathway ◽  
Statistical Significance ◽  
In Situ Hybridisation ◽  
Fluorescence In Situ Hybridisation ◽  
Normal Tissues

Abstract Background: Recent studies have shown that Long non-coding RNAs (lncRNAs) are crucial in the invasion, angiogenesis, progression, and metastasis of esophageal squamous cell carcinoma (ESCC). However, the biological functions and potential molecular mechanism of LncRNA GK-IT1 in esophageal squamous cell carcinoma has not been reported.Methods: We analysed the expression of GK-IT1 in ESCC and their adjacent normal tissues in the TCGA database. The quantitative real-time-PCR (qRT-PCR) was used to detect the expression of GK-IT1 in Clinical specimens. The Kaplan-Meier method was employed to draw the survival curve and then the statistical significance was calculated using the logarithmic rank test. a range of functional experiments in vivo and in vitro were used to explore the role of GK-IT1 in the carcinogenesis and development of ESCC. RNA pull down assay, RNA immunoprecipitation (RIP), fluorescence in situ hybridisation (FISH), agarose gel electrophoresis and immunofluorescence were all employed to explore the interaction mechanism between GK-IT1 and MAPK1 (mitogen activated protein kinase 1).Results: The expression of GK-IT1 was higher in ESCC than adjacent normal tissues, which was positively correlated with the clinical stage and shorter survival time. The knockout of the GK-IT1 gene significantly attenuated the abilities of ESCC cell proliferation, invasion and migration, induced apoptosis and autophagy in ESCC cells and inhibited tumour growth and tumour metastasis in vivo. on the contrary, the upregulation of GK-IT1 had the opposite effect. Further studies have shown that GK-IT1 can regulate the biological process of ESCC by regulating the phosphorylation of MAPK1.Conclusion: Our study reveals that GK-IT1 mediated the phosphorylation of MAPK1 improve the carcinogenesis and development of esophageal squamous cell carcinoma through ERK/MAPK pathway which indicates that GK-IT1 possesses substantial potential as a novel biomarker for ESCC prognosis and therapy.

scholarly journals Full-Field Viscoelastic Inflation Response of Bovine Cornea

2008 ◽  
Author(s):  
B. L. Boyce ◽  
T. D. Nguyen ◽  
R. E. Jones
Keyword(s):  
Real Time ◽  
Experimental Studies ◽  
Time Dependent ◽  
Full Field ◽  
3 Dimensional ◽  
Displacement Mapping ◽  
Mapping Tool ◽  
Unique Approach ◽  
In Vivo Characterization

Most previous experimental studies and mechanical cornea models have ignored time-dependence of the cornea’s modulus, with only a few notable exceptions [1–3]. The purpose of the present work was to evaluate the time-dependent properties of cornea tissue independent of scleral contributions in a condition that is as physiologically-relevant as possible without resorting to costly and difficult in vivo characterization. A non-contact 3-dimensional displacement mapping tool was employed to image the entire deformation field across the entire cornea in real-time during pressurization. Unlike prior inflation-based studies, the present study’s unique approach permits dynamic real-time full-field mapping of deformation during inflation for the examination of viscoelasticity, isotropy, and homogeneity.

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