Approximation of the Ribs-Bounded Contour in a Tomography Scan Slice

2018 ◽  
Vol 17 (01) ◽  
pp. 83-102
Author(s):  
Mykolas J. Bilinskas ◽  
Gintautas Dzemyda ◽  
Mantas Trakymas
Keyword(s):  
Mathematical Model ◽  
Least Squares ◽  
Computer Tomography ◽  
Bone Fracture ◽  
Ct Scans ◽  
Optimal Parameters ◽  
Internal Organs ◽  
Radiocontrast Agent ◽  
Transversal Plane ◽  
Tomography Scan

In this paper, a method for analyzing transversal plane images obtained by computer tomography (CT) scans is presented. A mathematical model that describes the ribs-bounded contour was created and the problem of approximation is solved by finding out the optimal parameters of the model in the least-squares sense. The paper discloses the problems that appear in building the proper model. Such a model would be useful in the registration of images independently on the patient position on the bed and of the radiocontrast agent injection. We consider the slices where ribs are visible because many important internal organs are located here: liver, heart, stomach, pancreas, lungs, etc. The model is flexible and describes the ribs-bounded contour independently on the patient age, sex and disease. The only exception is patients with the bone fracture. This makes the basis for the proper registration of slices.

scholarly journals Speeding-up the Fitting of the Model Defining the Ribs-bounded Contour

2017 ◽  
Vol 21 (1) ◽  
pp. 66-70
Author(s):  
Mykolas J. Bilinskas ◽  
Gintautas Dzemyda ◽  
Martynas Sabaliauskas
Keyword(s):  
Mathematical Model ◽  
Local Search ◽  
Computer Tomography ◽  
Vertical Axis ◽  
Newton Methods ◽  
Optimal Parameters ◽  
Analytical Derivatives ◽  
The Mathematical Model ◽  
Quasi Newton ◽  
Derivatives Of

Abstract The method for analysing transversal plane images from computer tomography scans is considered in the paper. This method allows not only approximating ribs-bounded contour but also evaluating patient rotation around the vertical axis during a scan. In this method, a mathematical model describing the ribs-bounded contour was created and the problem of approximation has been solved by finding the optimal parameters of the mathematical model using least-squares-type objective function. The local search has been per-formed using local descent by quasi-Newton methods. The benefits of analytical derivatives of the function are disclosed in the paper.

scholarly journals The identification of a device based on a Peltier element by the least squares method

2020 ◽  
pp. 17-27
Author(s):  
Vladimir Grinkevich ◽  
Keyword(s):  
Mathematical Model ◽  
Least Squares ◽  
Least Squares Method ◽  
Control Object ◽  
Object Identification ◽  
Model Parameters ◽  
Peltier Element ◽  
Transport Delay ◽  
Non Linear ◽  
The Mathematical Model

The evaluation of the mathematical model parameters of a non-linear object with a transport delay is considered in this paper. A temperature controlled stage based on a Peltier element is an identification object in the paper. Several input signal implementations are applied to the input of the identification object. The least squares method is applied for the calculation of the non-linear differential equitation parameters which describe the identification object. The least squares method is used due to its simplicity and the possibility of identification non-linear objects. The parameters values obtained in the process of identification are provided. The plots of temperature changes in the temperature control system with a controller designed based on the mathematical model of the control object obtained as a result of identification are shown. It is found that the mathematical model obtained in the process of identification may be applied to design controllers for non-linear systems, in particular for a temperature stage based on a Peltier element, and for self-tuning controllers. However, the least square method proposed in the paper cannot estimate the transport delay time. Therefore it is required to evaluate the time delay by temperature transient processes. Dynamic object identification is applied when it is required to obtain a mathematical model structure and evaluate the parameters by an input and output control object signal. Also, identification is applied for auto tuning of controllers. A mathematical model of a control object is required to design the controller which is used to provide the required accuracy and stability of control systems. Peltier elements are applied to design low-power and small- size temperature stage . Hot benches based on a Peltier element can provide the desired temperature above and below ambient temperature.

scholarly journals Gallbladder volvulus: a case report

2019 ◽  
pp. 1-2
Author(s):  
Tomas Urbonas
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Case Report ◽  
Computer Tomography ◽  
Small Proportion ◽  
Gold Standard ◽  
Crucial Role ◽  
Standard Treatment ◽  
Rare Condition ◽  
Computer Tomography Scan ◽  
Tomography Scan

The gallbladder volvulus is a rare condition. There have been around 500 cases described worldwide. It is virtually impossible to diagnose it clinically as symptoms are analogous to those of acute cholecystitis. Small proportion of gallbladder volvulus cases get accurately diagnosed preoperatively according to available literature. The imaging such as computer tomography plays a crucial role in diagnosing this condition. Laparoscopic cholecystectomy is considered to be a gold standard treatment for this condition. In our report we present a case of gallbladder volvulus which was successfully diagnosed by means of computer tomography scan

Optimal Design of a Six-Bar Linkage for an Anthropomorphic Three-Jointed Finger Mechanism

1992 ◽  
Author(s):  
Jichuan Zhang ◽  
Gongliang Guo ◽  
William A. Gruver
Keyword(s):  
Mathematical Model ◽  
Nonlinear Programming ◽  
Optimal Design ◽  
Transmission Efficiency ◽  
Degree Of Freedom ◽  
Optimal Parameters ◽  
Joint Friction ◽  
Robotic Devices ◽  
End Effectors ◽  
Human Finger

Abstract We treat the design of a three-jointed, anthropomorphic, finger mechanism for prostheses and robotic end-effectors. Based on the study of configurations for the human finger, we propose a six-bar linkage with one degree of freedom for the finger mechanism. A model of the fingertip displacement of the mechanism is derived by a vector analysis approach. We study the effects of joint friction on the transmission efficiency. By measuring the joint positions of a human finger, we develop a mathematical model of the pinching and holding configurations for the human finger. Optimal parameters for the finger mechanism are obtained by nonlinear programming based on motion posture, locus, transmission efficiency, and weight subject to geometric and bionic constraints. Simulations indicate that the mechanism is useful in a variety of prosthetic and robotic devices.

Computer Tomography Scan of the Hip and Pelvis

2021 ◽  
pp. 1-13
Author(s):  
Richard W. Kang ◽  
Erica Swartwout ◽  
Eric Bogner ◽  
Caroline Park ◽  
Anil Ranawat
Keyword(s):  
Computer Tomography ◽  
Computer Tomography Scan ◽  
Tomography Scan

THE FLOW FIELD ACTING ON THE FLUTTERING PROFILE, KINEMATICS, FORCES AND TOTAL MOMENT

2013 ◽  
Vol 13 (07) ◽  
pp. 1340009 ◽  
Author(s):  
JAN KOZÁNEK ◽  
VÁCLAV VLČEK ◽  
IGOR ZOLOTAREV
Keyword(s):  
Mathematical Model ◽  
Least Squares ◽  
High Speed ◽  
Least Squares Method ◽  
High Speed Camera ◽  
Aerodynamic Forces ◽  
Total Moment ◽  
Airfoil Surface ◽  
Measured System ◽  
Simplified Mathematical Model

A high speed camera was used for interferometry visualization (in different phases of the motion) of the fluttering NACA0015 profile supported in a translational and rotational manner. First, the simplified mathematical model of the support of investigated profile was identified from minimum least squares differences between modeled and measured system responses. A special graphical Matlab procedure was proposed for evaluation of interferograms. Kinematic analysis defining motion of the profile as a function of time was obtained by a regression using the least squares method. Numerical integration of pressure functions around the airfoil surface allows for calculation of the resulting aerodynamic forces and moments.

Prospective Study of the Correlation Between Postoperative Computed Tomography Scan and Primary Surgeon Assessment in Patients With Advanced Ovarian, Tubal, and Peritoneal Carcinoma Reported to Have Undergone Primary Surgical Cytoreduction to Residual Disease 1 cm or Less

2007 ◽  
Vol 25 (31) ◽  
pp. 4946-4951 ◽  
Author(s):  
Dennis S. Chi ◽  
Pedro T. Ramirez ◽  
Jerrold B. Teitcher ◽  
Svetlana Mironov ◽  
Debra M. Sarasohn ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Residual Disease ◽  
Advanced Ovarian Cancer ◽  
Ct Scans ◽  
Eligibility Criteria ◽  
Primary Surgery ◽  
The Right ◽  
Analysis Scale ◽  
Tomography Scan

Purpose To compare surgeons' operative assessments of residual disease (RD) to those identified on postoperative computed tomography (CT) scans in patients with advanced ovarian carcinoma reported to have undergone optimal primary cytoreduction. Patients and Methods All patients at one of two institutions, who were scheduled to have primary surgery for presumed advanced ovarian cancer, were asked to consent to a postoperative CT scan if cytoreduction to ≤ 1 cm RD was reported. CT scan findings were graded using a qualitative analysis scale from 1 (normal) to 5 (definitely malignant). Results From January 2001 to September 2006, 285 patients were enrolled. A total of 78 patients met eligibility criteria and had postoperative CT scans. In 41 cases (52%), postoperative scan findings correlated with the surgical report of no RD more than 1 cm, and in seven cases (9%), the CT findings were indeterminate. In 10 cases (13%), more than 1 cm RD was noted by the radiologist as probably malignant, and in 20 cases (26%), definitely malignant. In these 30 cases, the radiologically reported median largest residual mass was 1.9 cm (range, 1.1 to 5.1), with RD more than 1 cm reported most commonly in the right upper quadrant (15 patients [50%]) and central abdomen (nine patients [30%]). Conclusion There was only a 52% correlation between surgeons' assessments and postoperative CT scan evaluations of RD in patients reported to have undergone optimal cytoreduction. Further study is required to determine whether this lack of correlation is due to rapid interval tumor regrowth, RD underestimated by the surgeons, and/or overestimated by the radiologists; and to determine the clinical implications of these discrepancies.

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