scholarly journals Automatic analysis of cross‐sectional cerebral asymmetry on 3D in vivo MRI scans of human and chimpanzee

2019 ◽  
Vol 97 (6) ◽  
pp. 673-682
Author(s):  
Li Xiang ◽  
Timothy Crow ◽  
Neil Roberts
Keyword(s):  
Automatic Analysis ◽  
Cerebral Asymmetry ◽  
Cross Sectional ◽  
Mri Scans

Imaging

2017 ◽  
Author(s):  
Robert Laureno
Keyword(s):  
Resonance Imaging ◽  
Cross Sectional ◽  
Advantages And Disadvantages ◽  
Mri Scans ◽  
Cross Sectional Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Cellular Pathology ◽  
Brain And Spinal Cord ◽  
The Brain

This chapter on “Imaging” examines the relative advantages and disadvantages of computed tomography (CT) and magnetic resonance imaging (MRI) scans. It compares the modalities to each other and to gross neuropathology. For several decades, neurologists have been able to view cross-sectional images of living patients. Analogous to gross neuropathology, cross-sectional imaging displays the brain as an entire organ but does not demonstrate microscopic tissue or cellular pathology. By allowing practitioners to view sections of brain and spinal cord in vivo, imaging has improved neurologic practice and facilitated clinical research. This chapter deals with imaging topics that are important to the neurologist. The timing of scans, the effects of gravity, and the importance of plane of section are considered. Imaging is compared to gross neuropathology, and MRI is compared to CT.

scholarly journals Longitudinal Automatic Segmentation of Hippocampal Subfields (LASHiS) using Multi-Contrast MRI

2019 ◽  
Author(s):  
Thomas Shaw ◽  
Ashley York ◽  
Maryam Ziaei ◽  
Markus Barth ◽  
Steffen Bollmann ◽  
...  
Keyword(s):  
Automatic Segmentation ◽  
7 Tesla ◽  
Single Subject ◽  
Similarity Coefficients ◽  
Cross Sectional ◽  
Mri Scans ◽  
Contrast Information ◽  
Tissue Characteristics ◽  
Time Point

AbstractThe volumetric and morphometric examination of hippocampus formation subfields in a longitudinal manner using in vivo MRI could lead to more sensitive biomarkers for neuropsychiatric disorders and diseases including Alzheimer’s disease, as the anatomical subregions are functionally specialised. Longitudinal processing allows for increased sensitivity due to reduced confounds of inter-subject variability and higher effect-sensitivity than cross-sectional designs. We examined the performance of a new longitudinal pipeline (Longitudinal Automatic Segmentation of Hippocampus Subfields [LASHiS]) against three freely available, published approaches. LASHiS automatically segments hippocampus formation subfields by propagating labels from cross-sectionally labelled time point scans using joint-label fusion to a non-linearly realigned ‘single subject template’, where image segmentation occurs free of bias to any individual time point. Our pipeline measures tissue characteristics available in in vivo high-resolution MRI scans, at both clinical (3 Tesla) and ultra-high field strength (7 Tesla) and differs from previous longitudinal segmentation pipelines in that it leverages multi-contrast information in the segmentation process. LASHiS produces robust and reliable automatic multi-contrast segmentations of hippocampus formation subfields, as measured by higher volume similarity coefficients and Dice coefficients for test-retest reliability and robust longitudinal Bayesian Linear Mixed Effects results at 7 T, while showing sound results at 3 T. All code for this project including the automatic pipeline is available at https://github.com/CAIsr/LASHiS

Hair cell changes after cationic stimulation of corti's organ

1989 ◽  
Vol 47 ◽  
pp. 798-799
Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner
Keyword(s):  
Organ Of Corti ◽  
Cross Sectional ◽  
Surface Areas ◽  
High K ◽  
Anatomical Arrangement ◽  
Cell Cytosol ◽  
High Concentrations ◽  
K Concentration ◽  
Cell Changes

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.

scholarly journals Occupational Exposure to Carbon Nanotubes and Carbon Nanofibres: More Than a Cobweb

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 745
Author(s):  
Enrico Bergamaschi ◽  
Giacomo Garzaro ◽  
Georgia Wilson Jones ◽  
Martina Buglisi ◽  
Michele Caniglia ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Animal Studies ◽  
Chemical Properties ◽  
Biological Behavior ◽  
Cross Sectional ◽  
Carbon Nanofibres ◽  
Material Entity ◽  
Cross Sectional Design

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are erroneously considered as singular material entities. Instead, they should be regarded as a heterogeneous class of materials bearing different properties eliciting peculiar biological outcomes both in vitro and in vivo. Given the pace at which the industrial production of CNTs/CNFs is increasing, it is becoming of utmost importance to acquire comprehensive knowledge regarding their biological activity and their hazardous effects in humans. Animal studies carried out by inhalation showed that some CNTs/CNFs species can cause deleterious effects such as inflammation and lung tissue remodeling. Their physico-chemical properties, biological behavior and biopersistence make them similar to asbestos fibers. Human studies suggest some mild effects in workers handling CNT/CNF. However, owing to their cross-sectional design, researchers have been as yet unable to firmly demonstrate a causal relationship between such an exposure and the observed effects. Estimation of acceptable exposure levels should warrant a proper risk management. The aim of this review is to challenge the conception of CNTs/CNFs as a single, unified material entity and prompt the establishment of standardized hazard and exposure assessment methodologies able to properly feeding risk assessment and management frameworks.

scholarly journals Cross-sectional analysis of follow-up chest MRI and chest CT scans in patients previously affected by COVID-19

2021 ◽  
Author(s):  
Martina Pecoraro ◽  
Stefano Cipollari ◽  
Livia Marchitelli ◽  
Emanuele Messina ◽  
Maurizio Del Monte ◽  
...  
Keyword(s):  
Chest Ct ◽  
Ct Scans ◽  
Imaging Biomarker ◽  
Cross Sectional ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
Sectional Analysis ◽  
Ct And Mri ◽  
Interlobular Septal Thickening

Abstract Purpose The aim of the study was to prospectively evaluate the agreement between chest magnetic resonance imaging (MRI) and computed tomography (CT) and to assess the diagnostic performance of chest MRI relative to that of CT during the follow-up of patients recovered from coronavirus disease 2019. Materials and methods Fifty-two patients underwent both follow-up chest CT and MRI scans, evaluated for ground-glass opacities (GGOs), consolidation, interlobular septal thickening, fibrosis, pleural indentation, vessel enlargement, bronchiolar ectasia, and changes compared to prior CT scans. DWI/ADC was evaluated for signal abnormalities suspicious for inflammation. Agreement between CT and MRI was assessed with Cohen’s k and weighted k. Measures of diagnostic accuracy of MRI were calculated. Results The agreement between CT and MRI was almost perfect for consolidation (k = 1.00) and change from prior CT (k = 0.857); substantial for predominant pattern (k = 0.764) and interlobular septal thickening (k = 0.734); and poor for GGOs (k = 0.339), fibrosis (k = 0.224), pleural indentation (k = 0.231), and vessel enlargement (k = 0.339). Meanwhile, the sensitivity of MRI was high for GGOs (1.00), interlobular septal thickening (1.00), and consolidation (1.00) but poor for fibrotic changes (0.18), pleural indentation (0.23), and vessel enlargement (0.50) and the specificity was overall high. DWI was positive in 46.0% of cases. Conclusions The agreement between MRI and CT was overall good. MRI was very sensitive for GGOs, consolidation and interlobular septal thickening and overall specific for most findings. DWI could be a reputable imaging biomarker of inflammatory activity.

scholarly journals Simulating a Ground Truth for Transit Time Analysis of Indicator Dilution Curves

2020 ◽  
Vol 6 (3) ◽  
pp. 268-271
Author(s):  
Michael Reiß ◽  
Ady Naber ◽  
Werner Nahm
Keyword(s):  
Transit Time ◽  
Sampling Rate ◽  
Ground Truth ◽  
Indicator Dilution ◽  
Cross Sectional ◽  
In Vivo Measurements ◽  
Multiple Indicator Dilution ◽  
Transit Times ◽  
Dilution Curves

AbstractTransit times of a bolus through an organ can provide valuable information for researchers, technicians and clinicians. Therefore, an indicator is injected and the temporal propagation is monitored at two distinct locations. The transit time extracted from two indicator dilution curves can be used to calculate for example blood flow and thus provide the surgeon with important diagnostic information. However, the performance of methods to determine the transit time Δt cannot be assessed quantitatively due to the lack of a sufficient and trustworthy ground truth derived from in vivo measurements. Therefore, we propose a method to obtain an in silico generated dataset of differently subsampled indicator dilution curves with a ground truth of the transit time. This method allows variations on shape, sampling rate and noise while being accurate and easily configurable. COMSOL Multiphysics is used to simulate a laminar flow through a pipe containing blood analogue. The indicator is modelled as a rectangular function of concentration in a segment of the pipe. Afterwards, a flow is applied and the rectangular function will be diluted. Shape varying dilution curves are obtained by discrete-time measurement of the average dye concentration over different cross-sectional areas of the pipe. One dataset is obtained by duplicating one curve followed by subsampling, delaying and applying noise. Multiple indicator dilution curves were simulated, which are qualitatively matching in vivo measurements. The curves temporal resolution, delay and noise level can be chosen according to the requirements of the field of research. Various datasets, each containing two corresponding dilution curves with an existing ground truth transit time, are now available. With additional knowledge or assumptions regarding the detection-specific transfer function, realistic signal characteristics can be simulated. The accuracy of methods for the assessment of Δt can now be quantitatively compared and their sensitivity to noise evaluated.

scholarly journals 3D-Volume Rendering of the Pelvis with Emphasis on Paraurethral Structures Based on MRI Scans and Comparisons between 3D Slicer and OsiriX®

2021 ◽  
Vol 45 (3) ◽  
Author(s):  
C. M. Durnea ◽  
S. Siddiqi ◽  
D. Nazarian ◽  
G. Munneke ◽  
P. M. Sedgwick ◽  
...  
Keyword(s):  
Image Processing ◽  
Secondary Analysis ◽  
Three Dimensional ◽  
3D Models ◽  
Clinical Role ◽  
Cross Sectional ◽  
3D Slicer ◽  
Mri Scans ◽  
3D Volume ◽  
Good Agreement

AbstractThe feasibility of rendering three dimensional (3D) pelvic models of vaginal, urethral and paraurethral lesions from 2D MRI has been demonstrated previously. To quantitatively compare 3D models using two different image processing applications: 3D Slicer and OsiriX. Secondary analysis and processing of five MRI scan based image sets from female patients aged 29–43 years old with vaginal or paraurethral lesions. Cross sectional image sets were used to create 3D models of the pelvic structures with 3D Slicer and OsiriX image processing applications. The linear dimensions of the models created using the two different methods were compared using Bland-Altman plots. The comparisons demonstrated good agreement between measurements from the two applications. The two data sets obtained from different image processing methods demonstrated good agreement. Both 3D Slicer and OsiriX can be used interchangeably and produce almost similar results. The clinical role of this investigation modality remains to be further evaluated.

scholarly journals Rectus Femoris Mimicking Ultrasound Phantom for Muscle Mass Assessment: Design, Research, and Training Application

2021 ◽  
Vol 10 (12) ◽  
pp. 2721
Author(s):  
Nobuto Nakanishi ◽  
Shigeaki Inoue ◽  
Rie Tsutsumi ◽  
Yusuke Akimoto ◽  
Yuko Ono ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Rectus Femoris ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Phantom Model ◽  
Ultrasound Measurements ◽  
Ultrasound Phantom

Ultrasound has become widely used as a means to measure the rectus femoris muscle in the acute and chronic phases of critical illness. Despite its noninvasiveness and accessibility, its accuracy highly depends on the skills of the technician. However, few ultrasound phantoms for the confirmation of its accuracy or to improve technical skills exist. In this study, the authors created a novel phantom model and used it for investigating the accuracy of measurements and for training. Study 1 investigated how various conditions affect ultrasound measurements such as thickness, cross-sectional area, and echogenicity. Study 2 investigated if the phantom can be used for the training of various health care providers in vitro and in vivo. Study 1 showed that thickness, cross-sectional area, and echogenicity were affected by probe compression strength, probe angle, phantom compression, and varying equipment. Study 2 in vitro showed that using the phantom for training improved the accuracy of the measurements taken within the phantom, and Study 2 in vivo showed the phantom training had a short-term effect on improving the measurement accuracy in a human volunteer. The new ultrasound phantom model revealed that various conditions affected ultrasound measurements, and phantom training improved the measurement accuracy.

scholarly journals Atrophy patterns in isolated subscapularis lesions

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gernot Seppel ◽  
Andreas Voss ◽  
Daniel J. H. Henderson ◽  
Simone Waldt ◽  
Bernhard Haller ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Control Group ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subscapularis Muscle ◽  
Mri Scans ◽  
The Mean ◽  
The Cross

Abstract Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

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