Coronary CT angiography:Diagnostic value and clinical challenges

Coronary computed tomography(CT)angiography has been increasingly used in the diagnosis of coronary artery disease due to improved spatial and temporal resolution with high diagnostic value being reported when compared to invasive coronary angiography.Diagnostic performance of coronary CT angiography has been significantly improved with the technological developments in multislice CT scanners from the early generation of 4-slice CT to the latest 320-slice CT scanners.Despite the promising diagnostic value,coronary CT angiography is still limited in some areas,such as inferior temporal resolution,motion-related artifacts and high false positive results due to severe calcification.The aim of this review is to present an overview of the technical developments of multislice CT and diagnostic value of coronary CT angiography in coronary artery disease based on different generations of multislice CT scanners.Prognostic value of coronary CT angiography in coronary artery disease is also discussed,while limitations and challenges of coronary CT angiography are highlighted.

Radiation dose measurements in coronary CT angiography

Coronary computed tomography(CT)angiography is associated with high radiation dose and this has raised serious concerns in the literature.Awareness of various parameters for dose estimates and measurements of coronary CT angiography plays an important role in increasing our understanding of the radiation exposure to patients,thus,contributing to the implementation of dose-saving strategies.This article provides an overview of the radiation dose quantity and its measurement during coronary CT angiography procedures.

Coronary CT angiography:Beyond morphological stenosis analysis

Rapid technological developments in computed tomography(CT)imaging technique have made coronary CT angiography an attractive imaging tool in the detection of coronary artery disease.Despite visualization of excellent anatomical details of the coronary lumen changes,coronary CT angiography does not provide hemodynamic changes caused by presence of plaques.Computational fluid dynamics(CFD)is a widely used method in the mechanical engineering field to solve complex problems through analysing fluid flow,heat transfer and associated phenomena by using computer simulations.In recent years,CFD is increasingly used in biomedical research due to high performance hardware and software.CFD techniques have been used to study cardiovascular hemodynamics through simulation tools to assist in predicting the behaviour of circulatory blood flow inside the human body.Blood flow plays a key role in the localization and progression of coronary artery disease.CFD simulation based on 3D lumina reconstructions can be used to analyse the local flow fields and flow profiling due to changes of vascular geometry,thus,identifying risk factors for development of coronary artery disease.The purpose of this article is to provide an overview of the coronary CT-derived CFD applications in coronary artery disease.

Coronary CT angiography:Dose reduction strategies

With the introduction of 64- and post-64 slice computed tomography(CT)technology,coronary CT angiography has been increasingly used as a less invasive modality for the diagnosis of coronary artery disease.Despite its high diagnostic value and promising results compared to invasive coronary angiography,coronary CT angiography is associated with high radiation dose,leading to potential risk of radiation-induced cancer.A variety of dose-reduction strategies have been reported recently to reduce radiation dose with effective outcomes having been achieved.This article presents an overview of the various methods currently used for radiation dose reduction.

Endovascular stent graft repair of abdominal aortic aneurysms:Current status and future directions

Endovascular stent graft repair of abdominal aortic aneurysm(AAA)has undergone rapid developments since it was introduced in the early 1990s.Two main types of aortic stent grafts have been developed and are currently being used in clinical practice to deal with patients with complicated or unsuitable aneurysm necks,namely,suprarenal and fenestrated stent grafts.Helical computed tomography angiography has been widely recognized as the method of choice for both pre-operative planning and post-operative followup of endovascular repair(EVAR).In addition to 2D axial images,a number of 2D and 3D reconstructions are generated to provide additional information about imaging of the stent grafts in relation to the aortic aneurysm diameter and extent,encroachment of stent wires to the renal artery ostium and position of the fenestrated vessel stents.The purpose of this article is to provide an overview of applications of EVAR of AAA and diagnostic applications of 2D and 3D image visualizations in the assessment of treatment outcomes of EVAR.Interference of stent wires with renal blood flow from the hemodynamic point of view will also be discussed,and future directions explored.

冠的 CT angiography : 在词法狭窄分析以外

Rapid technological developments in computed tomography(CT)imaging technique have made coronary CT angiography an attractive imaging tool in the detection of coronary artery disease.Despite visualization of excellent anatomical details of the coronary lumen changes,coronary CT angiography does not provide hemodynamic changes caused by presence of plaques.Computational fluid dynamics(CFD)is a widely used method in the mechanical engineering field to solve complex problems through analysing fluid flow,heat transfer and associated phenomena by using computer simulations.In recent years,CFD is increasingly used in biomedical research due to high performance hardware and software.CFD techniques have been used to study cardiovascular hemodynamics through simulation tools to assist in predicting the behaviour of circulatory blood flow inside the human body.Blood flow plays a key role in the localization and progression of coronary artery disease.CFD simulation based on 3D lumina reconstructions can be used to analyse the local flow fields and flow profiling due to changes of vascular geometry,thus,identifying risk factors for development of coronary artery disease.The purpose of this article is to provide an overview of the coronary CT-derived CFD applications in coronary artery disease.

Coronary CT angiography:State of the art

Coronary computed tomography(CT)angiography has been recognized as the most rapidly developed imaging technique in the diagnosis of coronary artery disease due to the emergence and technological advances in multislice CT scanners.Coronary CT angiography has been confirmed to demonstrate high diagnostic and predictive value in coronary artery disease when compared to invasive coronary angiography.However,it suffers from high radiation dose which raises concerns in the medical field.Various dose-reduction strategies have been proposed with effective outcomes having been achieved to reduce radiation exposure to patients.This article provides an introduction and overview of the series of articles that will focus on each particular topic related to coronary CT angiography.

LCD MDS码的几类构造方法

线性互补对偶(linear complementary dual, LCD)码因其在数据存储和密码学方面的显著作用而受到广泛研究.线性互补对偶极大距离可分(LCD MDS (maximum distance separable))码具有最大的纠错能力,因而,构造LCD MDS码是LCD码理论研究的一个热点. Carlet等利用线性码的生成矩阵给出了LCD MDS码的存在性结果.最近,编码学者们基于广义Reed-Solomon码、代数几何码和常循环码等给出了LCD MDS码的显式构造.本文将介绍构造LCD MDS码的主要方法、结果以及最新进展.

Effect of Microstructure Scale on Negative Thermal Expansion of Antiperovskite Manganese Nitride

The negative thermal expansion （NTE） properties of the antiperovskite manganese nitrides with micron-scale, submicron-scale and nanometer-scale microstructures, respectively, were investigated using the Mn3Cu0.5Ge0.5N composition as an example. It was discovered that the NTE start temperature, NTE operation temperature range and coefficient of NTE change obviously in a wide range with decreasing the grain size level of the microstructure. The mechanisms for the broadening of the NTE operation temperature range and the decrease in the absolute value of NTE coefficient were proposed based on the grain-size-dependence of the frustrated magnetic interactions and magnetic ordering. The present study indicates that the NTE properties of the antiperovskite manganese nitrides can be tailored by the control of the microstructure scale.