Comparison of 3D deformable models for in vivo measurements of mouse embryo from 3D ultrasound images

DIC and DVC algorithms combined with smoothing algorithm were applied to ultrasound B mode images to generate 2D and 3D elastograms. The DIC based elastograms have better accuracy than conventional time-gradient based elastograms, and can estimate the size and the relative elastic modulus of the inclusion with a reasonable accurately. The study shows the potential to apply DIC and DVC based elastograms to the in-vivo diagnosis of pathological tissue within the body, and to provide new information that is related to tissue structure and/or pathology.

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Development of a semi-automated segmentation tool for high frequency ultrasound image analysis of mouse echocardiograms

Scientific Reports ◽

10.1038/s41598-021-85971-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kristi Powers ◽

Raymond Chang ◽

Justin Torello ◽

Rhonda Silva ◽

Yannick Cadoret ◽

...

Keyword(s):

Image Analysis ◽

Automated Analysis ◽

Structure And Function ◽

Ultrasound Images ◽

Cardiac Structure ◽

Short Axis ◽

Pixel Intensity ◽

Cardiac Structure And Function ◽

And Function

AbstractEchocardiography is a widely used and clinically translatable imaging modality for the evaluation of cardiac structure and function in preclinical drug discovery and development. Echocardiograms are among the first in vivo diagnostic tools utilized to evaluate the heart due to its relatively low cost, high throughput acquisition, and non-invasive nature; however lengthy manual image analysis, intra- and inter-operator variability, and subjective image analysis presents a challenge for reproducible data generation in preclinical research. To combat the image-processing bottleneck and address both variability and reproducibly challenges, we developed a semi-automated analysis algorithm workflow to analyze long- and short-axis murine left ventricle (LV) ultrasound images. The long-axis B-mode algorithm executes a script protocol that is trained using a reference library of 322 manually segmented LV ultrasound images. The short-axis script was engineered to analyze M-mode ultrasound images in a semi-automated fashion using a pixel intensity evaluation approach, allowing analysts to place two seed-points to triangulate the local maxima of LV wall boundary annotations. Blinded operator evaluation of the semi-automated analysis tool was performed and compared to the current manual segmentation methodology for testing inter- and intra-operator reproducibility at baseline and after a pharmacologic challenge. Comparisons between manual and semi-automatic derivation of LV ejection fraction resulted in a relative difference of 1% for long-axis (B-mode) images and 2.7% for short-axis (M-mode) images. Our semi-automatic workflow approach reduces image analysis time and subjective bias, as well as decreases inter- and intra-operator variability, thereby enhancing throughput and improving data quality for pre-clinical in vivo studies that incorporate cardiac structure and function endpoints.

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In Vivo Measurements of Cranial Electrical Stimulation Using Stereotactic-EEG: A Pilot Study

2021 10th International IEEE/EMBS Conference on Neural Engineering (NER) ◽

10.1109/ner49283.2021.9441106 ◽

2021 ◽

Author(s):

Minmin Wang ◽

Shenghua Zhu ◽

Haonan Guan ◽

Hongjie Jiang ◽

Jianmin Zhang ◽

...

Keyword(s):

Electrical Stimulation ◽

Pilot Study ◽

In Vivo Measurements

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

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2020-3068 ◽

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.

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