Noninvasive measurement of arterial diameters in humans using ultrasound echoes with prefiltered waveforms

A system for the direct measurement of the inner diameters of selected human arteriesin situ has been developed. Ultrasound pulses are emitted perdendicular to the vessel axis, and reflected from the wall material interfaces. Improved depth resolution is achieved by using a high-frequency transducer, and by inverse filtering of the signal. This is performed by emitting a waveform calculated beforehand to give an optimum time resolution in the received echo. Echoes from both innerand outer surfaces of the vessel walls are discriminated, and the inter-echo time intervals can be measured with an accuracy of 33ns, corresponding to approximately 26μm. By repeating the measurements through the cardiac cycle, the diameter variations can be accurately described.     

Ultrasonographic assessment of human skeletal muscle size

The measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered gold standard for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia.     

Application of Scanning Acoustic Microscopy for Assessing Stress Distribution in Atherosclerotic Plaque

Scanning acoustic microscopy (SAM) was equipped to assess the acoustic properties of normal and atherosclerotic coronary arteries. The SAM image in the atherosclerotic lesion clearly demonstrated that the sound speed was higher than that in the normal intima, and that the variation of elasticity was found within the fibrous cap of the plaque. Young's elastic modulus of each region was calculated and the finite element analysis was applied to derive the stress distribution in these arterial walls. In a case of normal coronary artery, the stress was dominant in the intima and the distribution was rather homogeneous and in a case of atherosclerosis, high stress was concentrated to the relatively soft lesion in the fibrous cap overlying lipid pool. SAM provides information on the physical properties, which cannot be obtained by the optical microscope. The results would help in understanding the pathological features of atherosclerosis. © 2001 Biomedical Engineering Society. PAC01: 8764-t, 8763Df, 8719Xx, 8719Rr     

超声筛查胎儿发育异常的回归模型构建研究

目的 用Logistic多因素非条件回归分析，建立超声筛查胎儿发育异常回归模型。方法对影响胎儿发育异常的各个因素进行非条件Logistic回归分析，计算标准偏回归系数、0R值等。结果共有7个因素进入方程，从各影响因素的标准偏回归系及OR值大小分析，以股骨、孕妇年龄、羊水对回归模型影响较大。结论胎儿发育异常与多种因素有关，股骨短小的孕妇应作为超声重点监测对象。     

超声波辐照后家兔肝脏超微结构的变化

本文作者用诊断剂量的超声波辐照活体家兔肝脏，喂养３ｄ致死后取材，经处理后用电子显微镜观察其超微结构的变化情况。实验结果表明超声波辐照２０ｍｉｎ的家兔肝脏的超檄结构无明显变化，而辐照３０ｍｉｎ及６０ｍｉｎ的家兔肝脏，除细胞质内粗面内质网有程度不同的扩张外，肝组织及肝细胞的其它结构均无明显改变。由于热效应与辐照时间有关，而本实验辐照３０ｍｉｎ及６０ｍｉｎ的家兔肝脏的超微结构的变化是相同的。且本实验所用超声强度小而不致引起机械效应。因此作者认为本实验出现的兔肝细胞粗面内质网扩张的现象不会是热效应和机械效应引起，而只可能是空化效应所致，这说明诊断超声可能在动物组织中引起空化效应。     

Outlining the prostate boundary using the harmonics method

In a computerised ultrasound image guidance for automated prostatectomy system, it is necessary to identify a smooth, continuous contour for the prostate (boundary) from the ultrasound image. The radial bas-relief (RBR) method, which has been reported previously, can extract a skeletonised image from an ultrasound image automatically. After this process the prostate boundary is clearly revealed. However, analysis of the image is far from complete, as there are many spurious branches that create too much ambiguity for the system to define the actual boundary. There are also sections missing from the prostate boundary. Therefore further post-processing is required to describe and define the prostate boundary. In the paper, the harmonics method is used to describe the prostate boundary. The harmonics method uses Fourier information for noise removal and encodes a smooth boundary. The results of using the harmonics method after application of the RBR method on ultrasound images are presented. Factors that affect the performance are also highlighted and discussed.     

Ultrasound in Obstructive Jaundice

The ultrasonographic findings of 44 patients, with obstructive jaundice were retrospectively reviewed. Our conclusions from this study are:

• (i) Ultrasound is an excellent modality for detecting dilatation of the biliary tree (in part or in total) and assessing the degree of dilatation, but it does not reliably detect the obstructing lesion often enough.
• (ii) It is important to adequately visualise the area of the extra-hepatic biliary tree and pancreatic head before suggesting the aetiology of any biliary tract dilatation regardless of the findings more proximally in the biliary tract.
• (iii) The optimal role of ultrasound is to detect a mass if one is present: tissue-typing requires histological or cytological examination of material from the mass.

     

超声联合血清TPO–Ab、Tg–Ab在桥本甲状腺炎临床进程评价中的应用价值

目的：探讨超声联合血清甲状腺过氧化物酶抗体（TPO–Ab）、甲状腺球蛋白抗体（Tg–Ab）评价桥本甲状腺炎（HT）临床进程的应用价值。方法：选择2021年9月至2022年8月贵州航天医院接诊的HT患者100例纳入观察组,另选择同期于贵州航天医院体检的健康者100例纳入对照组,两组研究对象均行彩色多普勒超声及血清TPO–Ab、Tg–Ab检查。比较两组研究对象血清TPO–Ab与Tg–Ab水平,并分析观察组患者术后病理或空心针穿刺活检组织病理学分级情况,以及观察组患者不同术后组织病理学分级患者血清TPO–Ab与Tg–Ab水平。以术后病理或空心针穿刺活检组织病理学分级为标准,评价超声、血清TPO–Ab与Tg–Ab单独及联合检测对观察组患者组织病理学分级的诊断准确度。结果：观察组患者血清TPO–Ab及Tg–Ab水平均高于对照组健康者,差异具有统计学意义（P <0.05）。观察组中,组织病理学分级为Ⅰ级的患者有58例,Ⅱ级有30例,Ⅲ级有12例;Ⅰ级患者血清TPO–Ab与Tg–Ab水平均低于Ⅱ、Ⅲ级患者,Ⅱ级患者血清TPO–Ab与Tg–Ab水平均低于Ⅲ级患者,差异均具有统计学意义（P <...     

不同影像技术对胰腺癌模型兔原位种植建模效果的评价与比较

目的:比较CT、MRI及超声平扫检查对胰腺癌模型兔建模效果的评价价值。方法:建立胰腺癌模型兔10只,对每只模型兔采用CT、MRI、超声平扫等影像检查,比较不同影像技术对模型兔肿瘤病灶的检出率;并对肿瘤采用磁共振波谱(MRS)分析肿瘤代谢情况。结果:建模成功3周末,死亡5只,存活5只;3种检查方式均能发现胰腺区的肿瘤病变和腹腔积液,检出率均能够达到100%。在对肿大淋巴结和血管包绕的检出中,MRI与CT的检出率相当,均优于超声平扫;在对远处转移的检出中,MRI要优于另外两种方式,但三种影像检查方法的病灶肿大淋巴结、血管包绕及远处转移等检出率比较,差异均无统计学意义(χ²=3.619,χ²=3.000,χ²=6.857;P>0.05)。MRS分析能够清晰显示胆碱(Ch)、肌酐(Cr)和N-乙酰天门冬氨酸(NAA)峰。结论:对动物肿瘤模型采用CT、MRI和超声平扫检查,可以获得较为满意的检测效果,但是在行动物实验过程中,需要根据实际的肿瘤种植位置和肿瘤转移位置采用合适的影像检查方法。