Patient-specific simulation of a gallbladder refilling based on MRI and ultrasound in vivo measurements

2020 ◽  
Author(s):  
Aleksey G. Kuchumov ◽  
Marat R. Kamaltdinov ◽  
Vladimir A. Samartsev ◽  
Aleksander R. Khairulin ◽  
Yulia A. Ivashova ◽  
...  
Keyword(s):  
Patient Specific ◽  
In Vivo Measurements

scholarly journals Biomechanical Models of the Hip – a Validation Study Based on 10 CT-Datasets

10.29007/rxxb ◽  
2018 ◽  
Author(s):  
Jörg Eschweiler ◽  
Malte Asseln ◽  
Philipp Damm ◽  
Maximilian C.M Fischer ◽  
Klaus Radermacher
Keyword(s):  
Hip Joint ◽  
Long Term Results ◽  
Patient Specific ◽  
Anatomical Landmarks ◽  
Joint Mechanics ◽  
X Ray ◽  
Biomechanical Models ◽  
In Vivo Measurements ◽  
The Impact

Consideration of the pre- and post-operative magnitude of the hip joint force R and its orientation Ɵ is of major importance for satisfactory long-term results in total hip arthroplasty. R and Ɵ can be computed by using biomechanical models with adapted geometrical/ anthropometrical parameters taken from clinical X-ray images. The objective of this study was to evaluate the models of Pauwels and Debrunner based on digital reconstructed-radiographs (central projection) from 10 CT-datasets of patients treated with telemetric hip-implants by a comparison to corresponding in-vivo measurements.R and Ɵ were computed for 10 patients with patient-specific geometric/anthropometric parameters. The model adaption was based on 28 anatomical landmarks. The root-mean-square-error of R is smaller for Debrunner (0.59/vs./0.66), and for Ɵ it is smaller for Pauwels’ (4.47/vs./7.78).Mathematical models provide potentially valuable information regarding hip joint mechanics. Regarding R, in all of the 10 patients the predictions of Pauwels’ model are consistently higher than the in-vivo measurements. Debrunner computed R in 8 cases higher and in 2 cases lower than the corresponding in-vivo forces. Pauwels’ and Debrunner showed similar tendencies: in 8 cases an overestimation of R and in 2 cases contrary results. Regarding Ɵ we found that in 5 cases the predictions of Pauwels’ are consistently higher than the in-vivo measurements and also contrary to Debrunner.As previous studies showed, an unambiguous identification of most landmarks in a 2D X-ray image is difficult. The impact of the pelvic tilt on the computational result was not considered in our study. Further investigation of this aspect is part of our ongoing work.

scholarly journals mRNA-Driven Generation of Transgene-Free Neural Stem Cells from Human Urine-Derived Cells

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1043 ◽  
Author(s):  
Phil Jun Kang ◽  
Daryeon Son ◽  
Tae Hee Ko ◽  
Wonjun Hong ◽  
Wonjin Yun ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Human Urine ◽  
Neurological Disorders ◽  
Therapeutic Potential ◽  
Embryonic Stem ◽  
Global Gene Expression ◽  
Patient Specific ◽  
Human Neural Stem Cells

Human neural stem cells (NSCs) hold enormous promise for neurological disorders, typically requiring their expandable and differentiable properties for regeneration of damaged neural tissues. Despite the therapeutic potential of induced NSCs (iNSCs), a major challenge for clinical feasibility is the presence of integrated transgenes in the host genome, contributing to the risk for undesired genotoxicity and tumorigenesis. Here, we describe the advanced transgene-free generation of iNSCs from human urine-derived cells (HUCs) by combining a cocktail of defined small molecules with self-replicable mRNA delivery. The established iNSCs were completely transgene-free in their cytosol and genome and further resembled human embryonic stem cell-derived NSCs in the morphology, biological characteristics, global gene expression, and potential to differentiate into functional neurons, astrocytes, and oligodendrocytes. Moreover, iNSC colonies were observed within eight days under optimized conditions, and no teratomas formed in vivo, implying the absence of pluripotent cells. This study proposes an approach to generate transplantable iNSCs that can be broadly applied for neurological disorders in a safe, efficient, and patient-specific manner.

Design, Fabrication, and Accuracy of a Novel Noncovering Lock-Mechanism Bilateral Patient-Specific Drill Guide Template for Nondeformed and Deformed Thoracic Spines

2021 ◽  
pp. 155633162199633
Author(s):  
Mehran Ashouri-Sanjani ◽  
Shima Mohammadi-Moghadam ◽  
Parisa Azimi ◽  
Navid Arjmand
Keyword(s):  
Thoracic Spine ◽  
Sagittal Plane ◽  
Ct Scanning ◽  
Entry Point ◽  
In Vivo Studies ◽  
Patient Specific ◽  
Plane Angle ◽  
Severe Scoliosis ◽  
3D Printed

Background: Pedicle screw (PS) placement has been widely used in fusion surgeries on the thoracic spine. Achieving cost-effective yet accurate placements through nonradiation techniques remains challenging. Questions/Purposes: Novel noncovering lock-mechanism bilateral vertebra-specific drill guides for PS placement were designed/fabricated, and their accuracy for both nondeformed and deformed thoracic spines was tested. Methods: One nondeformed and 1 severe scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific optimal (no perforation) drilling trajectories were determined on the CT images based on the entry point/orientation/diameter/length of each PS. Vertebra-specific templates were designed and 3D printed, assuring minimal yet firm contacts with the vertebrae through a noncovering lock mechanism. One model of each patient was drilled using the freehand and one using the template guides (96 pedicle drillings). Postoperative CT scans from the models with the inserted PSs were obtained and superimposed on the preoperative planned models to evaluate deviations of the PSs. Results: All templates fitted their corresponding vertebra during the simulated operations. As compared with the freehand approach, PS placement deviations from their preplanned positions were significantly reduced: for the nonscoliosis model, from 2.4 to 0.9 mm for the entry point, 5.0° to 3.3° for the transverse plane angle, 7.1° to 2.2° for the sagittal plane angle, and 8.5° to 4.1° for the 3D angle, improving the success rate from 71.7% to 93.5%. Conclusions: These guides are valuable, as the accurate PS trajectory could be customized preoperatively to match the patients’ unique anatomy. In vivo studies will be required to validate this approach.

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.

In vivo measurements of glenohumeral distraction technique performed in three different joint positions

2021 ◽  
pp. 1-7
Author(s):  
Diego Guerra-Rodríguez ◽  
Liliana Rozo ◽  
Daniel Basilio ◽  
Juan Guerrero-Henriquez
Keyword(s):  
In Vivo Measurements
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