Diagnostic Value of Spectral CT Reconstruction Mode for Carotid Atherosclerotic Plaque Lesions

Objective:To investigate the diagnostic value of spectral CT reconstruction mode for carotid atherosclerotic plaque lesions.Methods:From January 2017 to January 2019,70 patients with carotid atherosclerotic plaque lesions in our hospita1 were selected as the research object.A11 patients were diagnosed with cervical vascular color Doppler ultrasound and spectral CT scan under spectral cr reconstruction mode.Taking the results of coronaryf angiography as the"gold standard",the clinical value of the two examination methods in the diagnosis of carotid atherosclerotic plaque lesions was compared and analyzed.Results:Coronary angiography diagnosis confirmed that 33 of 70 patients with suspected carotid atherosclerotic plaque lesions had vulnerable plaques and 37 had stable plaques.The accuracy of Spectral CT examination of carotid artery plaque was 87.14%(61/70),sensitivity was 90.91%(30/33),specificity was 83.78%(31/37),and the positive predictive value was 83.33%(30/36),the negative predictive value is 91.76%(31/34),which is higher than that of cervical vascular ultrasonography(61.43%,60.61%,56.76%,57.89%,65.63%),the difference is statistically significant(P<0.05).Conclusion:The application of Spectral CT in the clinical diagnosis and treatment of carotid atherosclerotic plaque lesions with higher accuracy,sensitivity and specificity,is more significant and can provide a more reliable and effective imaging basis.

Gray weighted algorithm for variable voltage CT reconstruction

In conventional computed tomography （CT） reconstruction based on fixed voltage, the projective data often ap- pear overexposed or underexposed, as a result, the reconstructive results are poor. To solve this problem, variable voltage CT reconstruction has been proposed. The effective projective sequences of a structural component are obtained through the variable voltage. The total variation is adjusted and minimized to optimize the reconstructive results on the basis of iterative image using algebraic reconstruction technique （ART）. In the process of reconstruction, the reconstructive image of low voltage is used as an initial value of the effective proiective reconstruction of the adjacent high voltage, and so on until to the highest voltage according to the gray weighted algorithm. Thereby the complete structural information is reconstructed. Simulation results show that the proposed algorithm can completely reflect the information of a complicated structural com- ponent, and the pixel values are more stable than those of the conventional.

Randomized Kaczmarz algorithm for CT reconstruction

The order of the projection in the algebraic reconstruction technique(ART)method has great influence on the rate of the convergence.Although many scholars have studied the order of the projection,few theoretical proofs are given.Thomas Strohmer and Roman Vershynin introduced a randomized version of the Kaczmarz method for consistent,and over-determined linear systems and proved whose rate does not depend on the number of equations in the systems in 2009.In this paper,we apply this method to computed tomography(CT)image reconstruction and compared images generated by the sequential Kaczmarz method and the randomized Kaczmarz method.Experiments demonstrates the feasibility of the randomized Kaczmarz algorithm in CT image reconstruction and its exponential curve convergence.

Isogeometric Analysis of Hyperelastic Material Characteristics for Calcified Aortic Valve

This study explores the implementation of computed tomography(CT)reconstruction and simulation techniques for patient-specific valves,aiming to dissect the mechanical attributes of calcified valves within transcatheter heart valve replacement(TAVR)procedures.In order to facilitate this exploration,it derives pertinent formulas for 3D multi-material isogeometric hyperelastic analysis based on Hounsfield unit(HU)values,thereby unlocking foundational capabilities for isogeometric analysis in calcified aortic valves.A series of uniaxial and biaxial tensile tests is executed to obtain an accurate constitutive model for calcified active valves.To mitigate discretization errors,methodologies for reconstructing volumetric parametric models,integrating both geometric and material attributes,are introduced.Applying these analytical formulas,constitutive models,and precise analytical models to isogeometric analyses of calcified valves,the research ascertains their close alignment with experimental results through the close fit in displacement-stress curves,compellingly validating the accuracy and reliability of the method.This study presents a step-by-step approach to analyzing themechanical characteristics of patient-specific valves obtained fromCT images,holding significant clinical implications and assisting in the selection of treatment strategies and surgical intervention approaches in TAVR procedures.

Research on CT characteristics reconstruction technology

The traditional computed tomography(CT)reconstruction methods are noisy,low resolution,poor contrast,and generally not suitable to detect the smaller flaws.Besides,the filter design is also difficult.The CT characteristics reconstruction technology was brought forward to improve in these aspects,which is defined to directly reconstruct the characteristics of the projection for the best requirements not the overall image quality.The two-dimension(2D)and three-dimension(3D)CT characteristics reconstruction algorithm were firstly introduced,then by detailed analysis,experimental results and comparsion of parameters calculated,its advantages in keeping better high-frequency feature,better noise immunity,short time-consuming and easier design are verified.

Histopathologic Observation and Three Dimeninal CT Reconstruction of the Nasal Cavity and Paranasal Sinuses in Children with Cleft Palates

The morphologic characteristics of nasal cavity and paranasal sinuses in childred with cleft plaate were studied by

Digital measurement of bone tumor volume by CT three-dimensional reconstruction technology

Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital were included in the

Application of spiral CT three dimentional reconstruction on developmental dysplasis of the hip in children

Objective To evaluate the value of surface shaded reconstruction (SSD) of CT scanning on developmental dysplasia of the hip (DDK). Methods Unilateral DDH in 39 cases was examined with Picker 2000S spiral CT to perform SSD of the affected pelvis. All patients were females with the age ranging from 3.5 to 8 years old ( average 4.25 years). Of 39 cases, 22 cases were complete dislocation the hip, 17 cases were subluxation of the hip. The measurement of SSD included of the depth and surface area of normal and affected acetabulum; the distances from the lowest point of the bottom of the acetabulum (O point) to the anterior end (A point) of the lateral margin of anterior acetabular column (OA), the middle point (point) of the acetabular roof (OB) and the posterior end (C point) of lateral margin of the posterior acetabular column (OC). Results In normal hip, the medial and lateral margin of the acetabular roof was overlapping, and in DDH, a bony defect was found in the lateral acetabular margin in

Clinical Study on CT-guided Modified Akupotomye in the Treatment of Lumbar Nerve Posterior Branch Compression

Objective: To observe the clinical effect of modified akupotomye closed lysis under CT guidance on compression of posterior lumbar nerve branch.Methods: Patients were diagnosed by HRCT 3-D reconstruction combined with clinical symptoms and signs.After HRCT three-dimensional reconstruction combined with clinical symptoms and signs, the patients were confirmed as posterior lumbar nerve compression.After CT accurate surface positioning, CT-guided modified akupotomye was used for closed lysis of the posterior lumbar nerve branch.Oswestry Dysfunction Index Questionnaire(ODI) was used for quantitative scoring, 7 days before and after treatment and 6 months after treatment.Results: In 62 cases, 20 cases were cured, with 25 cases markedly effective, 11 cases effective, and 36 cases ineffective.The total effective rate was 90.3%.ODI score: Self-paired t test 7 days before after treatment, P < 0.01;Before treatment and 6 months after treatment, self-paired t test(P < 0.01);Self-paired t-test was performed 7 days after treatment and 6 months after treatment(P > 0.05).Conclusion: With CT precise positioning, the modified akupotomye can be used to do closed lysis, to relieve the adhesion and compression, so that the low back pain can be relieved, with good clinical.The akupotomye closed lysis, combined with modern imaging technology has not only achieved good clinical effect, but also can improve the accuracy, safety and scientificity of akupotomye treatment.

Improved projection-based energy weighting for spectral CT

Purpose Conventional X-ray CT scanners have limited ability to distinguish low-contrast substances.However,spectral CTs with photon counting detectors can identify photon energy and utilize spectral information,which is expected to achieve improved contrast.Energy weighting is a kind of reconstruction method for spectral CT.By assigning appropriate weight for each energy channel,the image contrast can be improved.Hence,how to determine the optimal weights is very important.Methods In this paper,we developed an improved projection-based energy weighting model for spectral CT.In this model,the object thickness of low-density materials is assumed as a constant,and the measured spectrum distribution is used to calculate the weight coefficients.Both phantom and tissue experiments were conducted in spectral CT scanner.Results The results showed that the thickness of low-density materials has little influence on the energy weight,so it can be regarded as a constant.For low-contrast phantom,the contrast-to-noise ratio was improved~32%by the proposed projectionbased weighting method.Conclusions The improved projection-based energy weighting model is effective in practice.It can increase the contrast of low-density materials.

A Splitting Primal-dual Proximity Algorithm for Solving Composite Optimization Problems

Our work considers the optimization of the sum of a non-smooth convex function and a finite family of composite convex functions, each one of which is composed of a convex function and a bounded linear operator. This type of problem is associated with many interesting challenges encoun- tered in the image restoration and image reconstruction fields. We developed a splitting primal-dual proximity algorithm to solve this problem. Furthermore, we propose a preconditioned method~ of which the iterative parameters are obtained without the need to know some particular operator norm in advance. Theoretical convergence theorems are presented. We then apply the proposed methods to solve a total variation regularization model, in which the L2 data error function is added to the L1 data error function. The main advantageous feature of this model is its capability to combine different loss functions. The numerical results obtained for computed tomography （CT） image recon- struction demonstrated the ability of the proposed algorithm to reconstruct an image with few and sparse projection views while maintaining the image quality.