Quantitative 4D Echocardiography using Fusion Techniques and Spatio-temporal Analysis

4D超声心动图（或实时3D超声心动图）是容量心脏成像领域的新成员，由于它可能取代对更昂贵的技术（MRI）的需求，并且还提出了容量心脏成像的新应用领域，例如在干预中。本研究项目建立在EPSRC GR/S72801的成功基础上，涉及定量4D超声心动图，特别是开发定量方法，用于估计4D超声心动图中心脏健康的全球和区域功能指标。融合四维超声心动图：EPSRC GR/S72801中最初研究的一种想法，融合来自2个或更多4D采集的信息，以获得比单一采集更完整的心脏解剖结构/功能表征。在之前的工作中，我们开发了融合的方法，并表明它可以产生更好的3D图像。在这个新项目中，我们计划研究自动定量分析（分割），我们假设它将优于融合四维超声心动图。我们还将研究组合对齐（配准）和分割技术，这是研究使定量融合四维超声心动图完全自动化并因此在临床实践中有用的自然下一步。2. 静息和应激超声心动图序列分析：应激超声心动图是一种广泛应用于临床实践的检查方法，在心脏处于静止状态时进行成像，然后在心脏受到应激后进行成像。尽管在临床诊断中使用的是两者之间的相对差异，但对应激超声心动图定量图像分析的有限工作将休息序列和应激序列分开处理。这部分项目的新颖想法是使用压力前和压力后序列来定义从训练序列中学习的健康/异常功能模型（数学上是隐马尔可夫模型）。我们在体积数据上做这个。在项目中，我们将建立这样的模型，并将其应用于最初的疾病分类，然后作为分割的约束。这两项发展都将推动临床4D超声心动图和3D心脏成像的发展。所开发的工具也可用于非心脏应用，例如产科和妇科（评估子宫健康）或肿瘤学（肿瘤对治疗的反应）。

4D echocardiography (or real-time 3D echocardiography) is a recent addition to the volumetric cardiac imaging field which is receiving significant clinical interest as it may replace the need for more expensive techniques (MRI) and also suggest new areas of application for volumetric cardiac imaging e.g. in interventions. This research project, building on the succces of EPSRC GR/S72801, concerns quantitative 4D echocardiography, and in particular developing quantitative methods for estimating global and regional functional measures of the health of the heart from 4D echocardiography The novelty in the project is built on two principal ideas.1. Fused 4D echocardiography: an idea, initially investigated in EPSRC GR/S72801, of fusing information from 2 or more 4D acquisitions to get an anatomically more complete representation of the structure/function of a heart than can be obtained from a single acquisition. In prior work we developed methodology for fusion and showed it led to superior 3D images. In this new project we plan to investigate automated quantitative analysis (segmentation) which we hypothese will be superior on fused 4D echocardiography. We will also investigate techniques for combined alignment (registration) and segmentation which is a natural next step to investigate towards making quantitative fused 4D echocardiography fully automated and hence useful in clinical practice. 2. Analysis of combined rest and stress echocardiographic sequences: Stress echocardiography is a widely used test in clinical practice where imaging is done when the heart is at rest and then after it has been stressed. The limited work on quantitative image analysis of stress echocardiography has treated rest and stress sequences separately even though it is the relative difference between the two that is used in clinical diagnosis. The novel idea in this part of the project is to use both pre and post stress sequences to define a model of healthy/abnormal function (mathematically a Hidden Markov Model) which is learned from training sequences. We do this on volumetric data. In the project we will build such models and apply them to initially classify disease and then as a constraint in segmentation.Both developments will advance clinical 4D echocardiography, and 3D cardiac imaging more generally. The developed tools may also find application in non-cardiac applications, such as in obstetrics and gynaecology (assessing the health of the uterus), or oncology (tumour response to treatment).