医学超声成像技术方法学进展

近几年来,超声成像技术的发展十分迅速,医学超声技术在基础研究、超声图像改善等多个领域取得了长足进展,尤其是计算机的发展及其在超声医学中的运用,不仅提高了已有的医学超声技术性能,还开发出许多新的技术,使超声诊断的方法更加丰富.现仅就以下新技术从方法学上作一初步评价.     

四维超声心动图成像方法学探讨（上）——方法学的建立

四维(动态三维)超声心动图是一项新的超声诊断技术,因其能客观再现心脏的立体结构而引起人们的兴趣与重视,本文介绍了四维超声心动图成像原理、步骤等方法学问题并对其进行了讨论。     

心瓣流场中湍流剪应力的方法学研究

本文从方法学的角度对目前心瓣流场中湍流剪应力体内外研究方法与检测技术及其优缺点进行了综合评估。鉴于诸多方法各自具有的不足，有关湍流剪应力的研究迄今尚缺乏一种较为理想的方法。指出体内无创研究是今后湍流剪应力的方法学研究的一个主要发展方向，不断普及的RMI与逐步完善的多维彩色多普勒超声技术将成为准确更高、较有前途的湍流剪应力检测方法。     

心瓣流场中湍流剪应力的方法学研究

本文从方法学的角度对目前心瓣流场中湍流剪应力体内外研究方法与检测技术及其优缺点进行了综合评估.鉴于诸多方法各自具有的不足,有关湍流剪应力的研究迄今尚缺乏一种较为理想的方法.指出体内无创研究是今后湍流剪应力方法学研究的一个主要发展方向,不断普及的MRI与逐步完善的多维彩色多普勒超声技术将成为准确性更高、较有前途的湍流剪应力检测方法.     

二尖瓣狭窄下游湍流剪应力体内多普勒超声定量检测的方法学研究

为建立与计算机图像分析技术相结合的人体二尖瓣狭窄下游湍流剪应力 (Turbulent shear stree,TSS)多普勒超声定量检测方法。本研究采用多普勒超声技术对正常人和不同程度二尖瓣狭窄病人组的二尖瓣下游血流速度频谱等指标进行多位点记录 ,通过计算机图像分析技术 ,测算出相关位点 TSS大小。结果表明不同程度二尖瓣狭窄组的二尖瓣下游核心位点 TSS与相对扰动强度 (Relative turbulent intensity,Irel)始终低于边界各位点 ;边界位点 TSS、Irel和流场均匀性等指标在正常对照和不同程度狭窄组之间均存在显著性差异 (P<0 .0 5 ) ,并均与有效瓣口面积 (Effective orifice area,EOA)明显相关。结论为二尖瓣有效开口面积越小 ,狭窄越重 ,射流边界 TSS和 Irel越大 ,射流核心区 TSS明显低于边界。研究结果显示 :应用与计算机图像分析相结合的多普勒超声技术所测人体二尖瓣狭窄下游 TSS与流场均匀性等常规多普勒超声指标具有良好的相关性 ,能共同反映不同狭窄程度病人瓣区血流动力学变化 ,因此表明本方法能比较准确地刻画人体二尖瓣狭窄下游 TSS的大小 ,并且 ,还具有安全无创、抗干扰能力强的特点 ,可用于瓣膜病病人瓣区流场中 TSS的定量分析。     

多普勒超声检测二尖瓣流场均匀性的方法学研究

为了建立体内天然二尖瓣流均匀性的多普勒超声定量检测方法，采用先进的彩色多普勒血流图像技术对正常人及二尖瓣狭窄患者二尖瓣下流场均匀性进行对比研究。发现流场均匀性定量指标在正常人及二尖瓣狭窄患者之间有显著差异，该指标与常规多普勒超声指标明显相关。该方法具有安全无创、准确可靠及可重复性强等优点，能台实地反映正常人及二尖瓣狭窄患者二尖瓣下游流场均匀性的优劣状况。     

超声造影在子宫肿瘤诊治中的应用

目的：探讨超声造影在子宫肿瘤诊断及治疗中的应用进展。方法：查阅近年来关于超声造影在子宫肿瘤治疗和诊断中应用方面的有关文献,进行分析总结。结果：超声造影能够提高对子宫肿瘤的诊断和鉴别诊断,并能对子宫肿瘤进行治疗和治疗效果的评价。结论：超声造影现在已成为超声医学领域的研究热点,但对于妇科疾病的研究尚处于初级阶段。对其进一步研究有助．于临床更好地诊断和治疗子宫肿瘤。     

医学实验技术课教学—方法学的研究与应用(摘要)

医学实验技术课教学—方法学的研究与应用（摘要）龚志锦詹熔洲戴益民余宏宇王建军（第二军医大学病理解剖学教研室，上海２００４３３）病理实验技术在医学中是一个不可缺少的重要组成部分。“方法学研究与应用”一课中，用以在本行业中具有成就的先进典型事例进行教学。...     

超声心动图在胎儿先心病诊断中的应用价值

目的研究超声心动图在胎儿先心病产前诊断中的临床应用价值。方法自2007年6月至2008年5月对5312例孕妇进行产前系统彩色多谱勒超声筛查,对心脏病高危胎儿应用超声心动图对其心脏进行检查。结果在彩色多谱勒超声筛查中发现心脏病高危胎儿413例。对心脏病高危胎儿应用超声心动图对其心脏进行检查,诊断为先心病的胎儿为31例,产后追踪随访及尸检确诊的先心病共38例,超声心动图诊断产前检出率为81.6%,漏诊率18.4%。结论超声心动图对产前诊断胎儿先心病具有重要的临床价值。     

TIL方法学研究进展

肿瘤浸润淋巴细胞(TIL)是继LAK细胞之后发现的又一类抗肿瘤免疫活性细胞,它具有更强而特异的抗瘤活性。当前,建立体外获得大量可供临床应用的具有高度而特异抗瘤活性的免疫效应细胞的方法和途径已成为人们致力研究的课题。本文着重介绍了TIL 分离制备和体外培养扩增等方法学研究进展。近年来,已基本建立起TIL 分离制备技术,在IL-2存在下TIL 能够有效增殖达1000倍以上;TIL 经冻存复苏后仍保持较好的增殖和抗瘤活性,这为临床长期应用TIL 提供了可能性。TIL 的研究为临床晚期肿瘤的治疗开辟了新途径。     

The cardiac magnetic resonance in the diagnosis of cardiac Raynaud phenomenon in a patient with systemic sclerosis: case report and review of literature

Raynaud phenomenon (RP) is the hallmark of Systemic Sclerosis (SSc). Visceral RP has also been proposed in SSc patients. Cardiac Raynaud’s phenomenon (C-RP) was evaluated in a few clinical studies both as cold-induced transient myocardial ischaemia and as presence of advanced myocardial fibrosis and contraction band necrosis in autopsied patients. Until today numerous techniques, such as scintigraphy and myocardial contrast echocardiography, have been used to evaluate C-RP. In this case report for the first time we have used Cardiac Magnetic Resonance (CMR) after cold test to demonstrate the presence of the C-RP. In addition we have shown that therapy with Iloprost can be used to reduce episodes of C-RP.     

Recent advances in echocardiographic diagnosis of ischemic heart disease

Before the early 1990s, the diagnostic usefulness of echocardiography for ischemic heart disease had been relatively limited compared with that for other cardiac diseases such as valvular disease, congenital anomalies and cardiomyopathies. The principal role of echocardiography was to assess persistent regional wall motion abnormality as well as to detect complications of myocardial infarction. However, recent technological advances have created many newer applications of echocardiography in this field. One of the most important advances was seen in the field of stress echocardiography. Dobutamine stress echocardiography has become an established method of diagnosing transient myocardial ischemia due to coronary stenosis and assessing the myocardial viability of a persistently akinetic segment. More recently, several new contrast agents have been developed or will be available in the near future to visualize the blood stream within the left heart cavity and myocardial blood flow. Simultaneously, new ultrasound technologies including harmonic imaging and gated intermittent imaging have enhanced the selective visualization of contrast agents and will contribute to noninvasive imaging of coronary microcirculation. Harmonic imaging has also been shown to improve quality of B-mode image without a contrast agent and will play an important role in the clinical recognition of wall motion abnormality in patients with ischemic heart disease. Recent advances in three-dimensional technology have enabled accurate measurements of left ventricular volume and ejection fraction without any geometrical assumption, which may be especially important for the evaluation of ischemic patients who often have a deformed left ventricular cavity due to remodeling.     

Diastolic compression of the right atrium and right ventricle as an echocardiographic sign of pericardial tamponade. Case report

A 33 years old female patient requiring regular hemodialysis for chronic renal failure exhibited a severe hypotensive episode. 2-dimensional echocardiography enabled rapid recognition of the underlying cause. 2-dimensional echocardiography revealed a large pericardial effusion and from the apical window a marked diastolic compression of the right atrium and the right ventricle was noted. These findings have been previously described to be specific for cardiac tamponade. After removal of 400 ml of fluid by pericardiocentesis the clinical symptoms rapidly improved and in the 2-dimensional echocardiography diastolic compression of the right sided heart chambers was not longer evident, although a substantial amount of pericardial fluid was still present. This case report underlines the clinical usefulness of 2-dimensional echocardiography for the diagnosis of cardiac tamponade.     

Uraemic pericarditis, an epidemic disease?

Pericarditis (PC) is a frequent complication with renal failure. Numerous causes have been proposed. Over a six week period, we observed five cases of PC in five of 102 patients on maintenance haemodialysis. Viral cause was suspected in one case (Respiratory Syncytial Virus). During the past year, no recurrence of PC has been seen. The case clustering episodes might suggest a viral cause. The value of examining the patients by stetoscopy and echocardiography was documented.     

From genotype to phenotype: a longitudinal study of a patient with hypertrophic cardiomyopathy due to a mutation in the MYBPC3 gene

Many of the links between the genotype and phenotype in hypertrophic cardiomyopathy remain unexplained. In this unique longitudinal study we have investigated a patient with classical clinical phenotypic features of hypertrophic obstructive cardiomyopathy, with a known mutation in MYBPC3, the most commonly affected gene in this disease. By collecting cardiac tissue from the patient at the time of surgical myectomy for relief of left ventricular outflow tract obstruction, we have been able to examine the structure of the myocytes and the functional differences that occur in MyBP-C mutated HCM cardiac tissue from single protein level, onto single cardiomyocyte contractility, through to whole organ function as assessed clinically by echocardiography.     

基于BiSeNet的小儿超声心动图左心分割方法

小儿超声心动图分割是后续生物学参数测量与疾病诊断的关键一步。目前,这主要依赖于超声医生的手动分割,不仅耗时耗力,而且由于它的重复性与冗余性,常常会导致不准确的分割。深度学习方法在自然图像处理领域已经取得令人瞩目的成果,因此提出应用深度卷积神经网络,从小儿超声心动图中学习有效特征,进行左心关键解剖结构的分割。具体来说,提出使用双路径分割网络(BiSeNet),通过两路分支网络,分别提取低层和高层的特征,然后送入一个特征融合模块,筛选出有效的特征,从而得到准确的分割结果。在采集自深圳儿童医院超声科的包含87个超声心动图视频(2 216张图像)的数据集上进行验证,并与医生的标注结果进行比较。实验结果表明,BiSeNet可以提取到超声心动图中心脏结构的特征,它在左室和左房的分割任务上取得Dice系数高达0.914和0.887。这证明,所提出的方法可以帮助医生进行超声心动图分割,从而减轻医生的负担。     

Computer analysis of echocardiograms

Owing to its non-invasive nature, echocardiography, is widely used in many fields of clinical sciences. Especially in cardiology, real-time pictures of the beating heart are now essential in clinical practice. With recent developments of computer technology, various aspects of computerization have been introduced into echocardiography. Analysis of cardiac function became easier by automated echocardiography with three dimensional framework, length-tension-velocity. A 3-dimensional view of the heart could also be obtained by computerized image processing of serial echocardiograms. The results of the automated analysis by computer were in good agreement with those with manual measurements. Therefore, the computer processing is valid. These kinds of computer image processing of echocardiograms would be useful in various clinical settings.     

2D to 3D fusion of echocardiography and cardiac CT for TAVR and TAVI image guidance

This study proposed a registration framework to fuse 2D echocardiography images of the aortic valve with preoperative cardiac CT volume. The registration facilitates the fusion of CT and echocardiography to aid the diagnosis of aortic valve diseases and provide surgical guidance during transcatheter aortic valve replacement and implantation. The image registration framework consists of two major steps: temporal synchronization and spatial registration. Temporal synchronization allows time stamping of echocardiography time series data to identify frames that are at similar cardiac phase as the CT volume. Spatial registration is an intensity-based normalized mutual information method applied with pattern search optimization algorithm to produce an interpolated cardiac CT image that matches the echocardiography image. Our proposed registration method has been applied on the short-axis “Mercedes Benz” sign view of the aortic valve and long-axis parasternal view of echocardiography images from ten patients. The accuracy of our fully automated registration method was 0.81 ± 0.08 and 1.30 ± 0.13 mm in terms of Dice coefficient and Hausdorff distance for short-axis aortic valve view registration, whereas for long-axis parasternal view registration it was 0.79 ± 0.02 and 1.19 ± 0.11 mm, respectively. This accuracy is comparable to gold standard manual registration by expert. There was no significant difference in aortic annulus diameter measurement between the automatically and manually registered CT images. Without the use of optical tracking, we have shown the applicability of this technique for effective fusion of echocardiography with preoperative CT volume to potentially facilitate catheter-based surgery.     

Improvement in the diagnosis of abscesses associated with endocarditis by transesophageal echocardiography

BACKGROUND. Echocardiography is recognized as the method of choice for the noninvasive detection of valvular vegetations in patients with infective endocarditis, with transesophageal echocardiography being more accurate than transthoracic echocardiography. The diagnosis of associated abscesses by transthoracic echocardiography is difficult or even impossible in many cases, however, and it is not known whether transesophageal echocardiography is any better. METHODS. To determine the value of transesophageal echocardiography in the detection of abscesses associated with endocarditis, we studied prospectively by two-dimensional transthoracic and transesophageal echocardiography 118 consecutive patients with infective endocarditis of 137 native or prosthetic valves that was documented during surgery or at autopsy. RESULTS. During surgery or at autopsy, 44 patients (37.3 percent) had a total of 46 definite regions of abscess. Abscesses were more frequent in aortic-valve endocarditis than in infections of other valves, and the infecting organism was more often staphylococcus (52.3 percent of cases) in patients with abscesses than in those without abscesses (16.2 percent). The hospital mortality rate was 22.7 percent in patients with abscesses, as compared with 13.5 percent in patients without abscesses. Whereas transthoracic echocardiography identified only 13 of the 46 areas of abscess, the transesophageal approach allowed the detection of 40 regions (P less than 0.001). Sensitivity and specificity for the detection of abscesses associated with endocarditis were 28.3 and 98.6 percent, respectively, for transthoracic echocardiography and 87.0 and 94.6 percent for transesophageal echocardiography; positive and negative predictive values were 92.9 and 68.9 percent, respectively, for the transthoracic approach and 90.9 and 92.1 percent for the transesophageal approach. Variation between observers was 3.4 percent for transthoracic and 4.2 percent for transesophageal echocardiography. CONCLUSIONS. The data indicate that transesophageal echocardiography leads to a significant improvement in the diagnosis of abscesses associated with endocarditis. The technique facilitates the identification of patients with endocarditis who have an increased risk of death and permits earlier treatment.     

Non-invasive assessment of cardiac function

Noninvasive assessment of cardiac function by Doppler echocardiography is reviewed. The heart propels the blood through the repeated sequence of systole and diastole. The systolic function is essential to maintain the biological function of the whole body. However, before the heart ejects the blood during systole, the heart must be filled up with blood during the preceding diastole. Thus, the diastolic function is as important as the systolic function. Although the diastolic function is traditionally assessed by hemodynamic parameters obtained in the cardiac catheterization laboratory, it has routinely been assessed by Doppler echocardiography in the echocardiographic laboratory in recent years. Since the concept of diastolic failure has widely spread, the important role of the transmitral flow in assessing the diastolic function has been well recognized. Besides the transmitral flow, the modalities for clinical assessment of the left ventricular diastolic function have been well developed. For example, the pulmonary venous flow has been easily obtained by a transthoracic approach, and the tissue Doppler technique provides important information about the diastolic function, and furthermore the color M-mode is applied for the flow propagation velocity of the left ventricular inflow. These modalities make it possible to assess the left ventricular diastolic function more precisely by Doppler echocardiography. Also, TEI index, strain rate and strain imaging, and wave intensity are mentioned.