Evaluation of biological effects induced by diagnostic ultrasound in the rat foetal tissues

In recent years, there has been growing interest in estimating the degree of heating caused by the diagnostic ultrasound in clinical practice. Both theoretical and experimental methods have been suggested for estimating the heating potential, or thermal hazard, of diagnostic ultrasound. Aim of this study was to evaluate in vivo effects of ultrasound exposure of variable duration (from 10 up to 20 min) with commercially available imaging systems commonly used for diagnostic imaging. Numerical results related to the thermal effect are obtained by simulation program based on B-mode (scanning) and Doppler (non-scanning). To investigate the biological effects of the ultrasound exposure to the brain and liver tissues, the antioxidant enzyme activity and thiobarbituric acid reactive substances (TBARS) of the tissues were evaluated. In liver tissue, as a lipid peroxidation index, TBARS levels very significantly increase in Doppler group compared to control. However, in B-mode, TBARS levels are the same with the control group. Use of B-mode in foetal tissue is more reliable than Doppler mode because temperature rise is very small compared to the Doppler mode. On the other hand, the antioxidant enzyme activities tend to increase in B-mode and Doppler groups compared to the control group as a defensive mechanism. In the brain tissue, lipid peroxidation is increased slightly in B-mode compared to the control group. This situation is related to the molecular structure of the brain tissue because of its high lipid concentration. In brain tissue, the antioxidant enzyme activities and lipid peroxidation were significantly increased, such as liver tissue in Doppler groups. Doppler ultrasound may produce harmful effects in rat foetus liver and brain tissues as a result of the high temperature rises.     

Design of lymphedema ultrasound phantom with 3D-printed patient-specific subcutaneous anatomy: A-mode analysis approach for early diagnosis

The secondary lymphedema is mostly caused due to injury of lymphatic system during cancer treatment and its psychological and cosmetic issues are very critical for patients since it can cause severe thickening and swelling of lesions, mostly upper and lower limbs. Therefore, early diagnosis of the secondary lymphedema is more important to treat the symptoms in advance. The amplitude-mode (A-mode) ultrasound is suggested as an early diagnostic modality because it is relatively more cost-effective, portable, and easy to use than other previous diagnostic modalities. In order to see features of the A-mode ultrasound forearly diagnosis of lymphedema, ultrasound lymphedema phantoms were designed and fabricated with patient-specific subcutaneous honeycomb structures at the sub-stages of the international society of lymphedema (ISL) stage II and gelatin- or gelatin-salt based phantom materials. The patent-specific honeycomb structures were segmented from computed tomography (CT) venography images using various image process technologies and printed using a three dimensional (3D) printer for which its printing material shows similar acoustic impedance range with human subcutaneous tissues. The lymphedema phantoms showed similar subcutaneous anatomical features to those of patient's imagesin brightness mode (B-mode) ultrasound examination, and acoustic information originated from the stage-specific honeycomb structures was well represented in A-mode ultrasound examination. In particular, the A-mode wave form well represented stage-specific honeycomb information even with higher impedance value of fibrous fat region. Such stage-specific wave form information of A-mode ultrasound for the corresponding stage-specific lymphedema phantoms at the ISL stage II can be useful for further development of an A-mode ultrasound applications for early diagnosis of the secondary lymphedema.     

Comparison of the diagnostic capacities of imaging methods for childhood hemangiomas

The diagnostic capacities of three imaging methods: B-mode ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) in orbital hemangiomas in babies were compared. Orbital ultrasound, computed tomography, and MRI scans were examined in 358, 384, and 48 babies, respectively. Their mean age was 6.7 months. Out of three techniques, ultrasound scanning proved to be of less informative value. MRI and CT were much more informative although each of them had advantages and limitations. The authors give some preference to CT despite its ionization.     

眼部常见疾病的超声诊断分析

目的：总结眼部常见疾病的超声表现,探讨超声对其的诊断价值。方法：对2009年6月～2010年6月来我院超声科行眼部超声检查（占位性病变经手术或病理学结果证实）的63例患者的资料进行回顾性分析,归纳总结了眼部常见疾病的二维超声（2D）、彩色多普勒（CDFI）及超声造影（CEUS）表现。结果：眼部疾病的超声图像在位置、形状、边界、声学特点及对周围组织的影响等方面具有特征性表现;超声造影能有效地显示出病灶内的血管及血流灌注情况。结论：超声对眼部常见病的诊断是一种简便、无创、经济且诊断符合率高的辅助影像学方法,具有较高的实际应用价值。     

High-frequency Ultrasound Imaging of Mouse Cervical Lymph Nodes

High-frequency ultrasound (HFUS) is widely employed as a non-invasive method for imaging internal anatomic structures in experimental small animal systems. HFUS has the ability to detect structures as small as 30 µm, a property that has been utilized for visualizing superficial lymph nodes in rodents in brightness (B)-mode. Combining power Doppler with B-mode imaging allows for measuring circulatory blood flow within lymph nodes and other organs. While HFUS has been utilized for lymph node imaging in a number of mouse  model systems, a detailed protocol describing HFUS imaging and characterization of the cervical lymph nodes in mice has not been reported. Here, we show that HFUS can be adapted to detect and characterize cervical lymph nodes in mice. Combined B-mode and power Doppler imaging can be used to detect increases in blood flow in immunologically-enlarged cervical nodes. We also describe the use of B-mode imaging to conduct fine needle biopsies of cervical lymph nodes to retrieve lymph tissue for histological  analysis. Finally, software-aided steps are described to calculate changes in lymph node volume and to visualize changes in lymph node morphology following image reconstruction. The ability to visually monitor changes in cervical lymph node biology over time provides a simple and powerful technique for the non-invasive monitoring of cervical lymph node alterations in preclinical mouse models of oral cavity disease.     

State of the Art Cranial Ultrasound Imaging in Neonates

Cranial ultrasound (CUS) is a reputable tool for brain imaging in critically ill neonates. It is safe, relatively cheap and easy to use, even when a patient is unstable. In addition it is radiation-free and allows serial imaging. CUS possibilities have steadily expanded. However, in many neonatal intensive care units, these possibilities are not optimally used. We present a comprehensive approach for neonatal CUS, focusing on optimal settings, different probes, multiple acoustic windows and Doppler techniques. This approach is suited for both routine clinical practice and research purposes. In a live demonstration, we show how this technique is performed in the neonatal intensive care unit. Using optimal settings and probes allows for better imaging quality and improves the diagnostic value of CUS in experienced hands. Traditionally, images are obtained through the anterior fontanel. Use of supplemental acoustic windows (lambdoid, mastoid, and lateral fontanels) improves detection of brain injury. Adding Doppler studies allows screening of patency of large intracranial arteries and veins. Flow velocities and indices can be obtained. Doppler CUS offers the possibility of detecting cerebral sinovenous thrombosis at an early stage, creating a window for therapeutic intervention prior to thrombosis-induced tissue damage. Equipment, data storage and safety aspects are also addressed.     

Mesadenitis in children with acute abdominal pain syndrome: clinical and echographic parallels

The paper pools the experience of ultrasound assessment of acute mesadenitis in children with acute abdominal pain syndrome. It reviews the literature on its etiology, pathology, and diagnosis and treatment principles. B-mode and Doppler echograms made by general practice ultrasound diagnosticians are shown. The technique is demonstrated to be effective and of informative value in the early stages of diagnosis in the patient contingent in question.     

High-Resolution Harmonics Ultrasound Imaging for Non-Invasive Characterization of Wound Healing in a Pre-Clinical Swine Model

This work represents the first study employing non-invasive high-resolution harmonic ultrasound imaging to longitudinally characterize skin wound healing. Burn wounds (day 0-42), on the dorsum of a domestic Yorkshire white pig were studied non-invasively using tandem digital planimetry, laser speckle imaging and dual mode (B and Doppler) ultrasound imaging. Wound depth, as measured by B-mode imaging, progressively increased until day 21 and decreased thereafter. Initially, blood flow at the wound edge increased up to day 14 and subsequently regressed to baseline levels by day 21, when the wound was more than 90% closed. Coinciding with regression of blood flow at the wound edge, there was an increase in blood flow in the wound bed. This was observed to regress by day 42. Such changes in wound angiogenesis were corroborated histologically. Gated Doppler imaging quantitated the pulse pressure of the primary feeder artery supplying the wound site. This pulse pressure markedly increased with a bimodal pattern following wounding connecting it to the induction of wound angiogenesis. Finally, ultrasound elastography measured tissue stiffness and visualized growth of new tissue over time. These studies have elegantly captured the physiological sequence of events during the process of wound healing, much of which is anticipated based on certain dynamics in play, to provide the framework for future studies on molecular mechanisms driving these processes. We conclude that the tandem use of non-invasive imaging technologies has the power to provide unprecedented insight into the dynamics of the healing skin tissue.     

Targeting of ovarian cancer cell through functionalized gold nanoparticles by novel glypican-3- binding peptide as a ultrasound contrast agents

Gold nanoparticles (AuNPs) are widely studied nanomaterials for their potential employment in advanced biomedical applications, such as selective molecular imaging and targeted drug delivery. AuNPs are generally low cost and highly biocompatible, can be easily functionalized with a wide variety of functional ligands, and have been demonstrated to be effective in enhancing ultrasound contrast at clinical diagnostic frequencies. Therefore, AuNPs might be used as contrast agents in echographic imaging. In this work, we have developed a AuNPs -based system for the in vitro molecular imaging of ovarian carcinoma cells that express high levels of glypican-3 protein (GPC-3) on their surface. In this regard, a novel GPC-3 targeting peptide was designed and conjugated to fluorescent AuNPs nanoparticles. The physicochemical properties, acoustic behavior, and biocompatibility profile of the functionalized AuNPs were characterized. Then, the binding and uptake of both naked and functionalized AuNPs were analyzed by laser scanning confocal microscopy in human HeLa cells (ovarian carcinoma) cell line. The results obtained showed that GPC-3-functionalized fluorescent AuNPs significantly enhanced the ultrasound contrast and were effectively bound and taken up by HeLa cells without affecting their viability.     

Echo Particle Image Velocimetry

The transport of mass, momentum, and energy in fluid flows is ultimately determined by spatiotemporal distributions of the fluid velocity field.¹ Consequently, a prerequisite for understanding, predicting, and controlling fluid flows is the capability to measure the velocity field with adequate spatial and temporal resolution.² For velocity measurements in optically opaque fluids or through optically opaque geometries, echo particle image velocimetry (EPIV) is an attractive diagnostic technique to generate "instantaneous" two-dimensional fields of velocity.^3,4,5,6 In this paper, the operating protocol for an EPIV system built by integrating a commercial medical ultrasound machine⁷ with a PC running commercial particle image velocimetry (PIV) software⁸ is described, and validation measurements in Hagen-Poiseuille (i.e., laminar pipe) flow are reported.For the EPIV measurements, a phased array probe connected to the medical ultrasound machine is used to generate a two-dimensional ultrasound image by pulsing the piezoelectric probe elements at different times. Each probe element transmits an ultrasound pulse into the fluid, and tracer particles in the fluid (either naturally occurring or seeded) reflect ultrasound echoes back to the probe where they are recorded. The amplitude of the reflected ultrasound waves and their time delay relative to transmission are used to create what is known as B-mode (brightness mode) two-dimensional ultrasound images. Specifically, the time delay is used to determine the position of the scatterer in the fluid and the amplitude is used to assign intensity to the scatterer. The time required to obtain a single B-mode image, t, is determined by the time it take to pulse all the elements of the phased array probe. For acquiring multiple B-mode images, the frame rate of the system in frames per second (fps) = 1/δt. (See 9 for a review of ultrasound imaging.)For a typical EPIV experiment, the frame rate is between 20-60 fps, depending on flow conditions, and 100-1000 B-mode images of the spatial distribution of the tracer particles in the flow are acquired. Once acquired, the B-mode ultrasound images are transmitted via an ethernet connection to the PC running the PIV commercial software. Using the PIV software, tracer particle displacement fields, D(x,y)[pixels], (where x and y denote horizontal and vertical spatial position in the ultrasound image, respectively) are acquired by applying cross correlation algorithms to successive ultrasound B-mode images.¹⁰ The velocity fields, u(x,y)[m/s], are determined from the displacements fields, knowing the time step between image pairs, ΔT[s], and the image magnification, M[meter/pixel], i.e., u(x,y) = MD(x,y)/ΔT. The time step between images ΔT = 1/fps + D(x,y)/B, where B[pixels/s] is the time it takes for the ultrasound probe to sweep across the image width. In the present study, M = 77[μm/pixel], fps = 49.5[1/s], and B = 25,047[pixels/s]. Once acquired, the velocity fields can be analyzed to compute flow quantities of interest.     

Comparison of Optical and Power Doppler Ultrasound Imaging for Non-Invasive Evaluation of Arsenic Trioxide as a Vascular Disrupting Agent in Tumors

Small animal imaging provides diverse methods for evaluating tumor growth and acute response to therapy. This study compared the utility of non-invasive optical and ultrasound imaging to monitor growth of three diverse human tumor xenografts (brain U87-luc-mCherry, mammary MCF7-luc-mCherry, and prostate PC3-luc) growing in nude mice. Bioluminescence imaging (BLI), fluorescence imaging (FLI), and Power Doppler ultrasound (PD US) were then applied to examine acute vascular disruption following administration of arsenic trioxide (ATO).During initial tumor growth, strong correlations were found between manual caliper measured tumor volume and FLI intensity, BLI intensity following luciferin injection, and traditional B-mode US. Administration of ATO to established U87 tumors caused significant vascular shutdown within 2 hrs at all doses in the range 5 to 10 mg/kg in a dose dependant manner, as revealed by depressed bioluminescent light emission. At lower doses substantial recovery was seen within 4 hrs. At 8 mg/kg there was >85% reduction in tumor vascular perfusion, which remained depressed after 6 hrs, but showed some recovery after 24 hrs. Similar response was observed in MCF7 and PC3 tumors. Dynamic BLI and PD US each showed similar duration and percent reductions in tumor blood flow, but FLI showed no significant changes during the first 24 hrs.The results provide further evidence for comparable utility of optical and ultrasound imaging for monitoring tumor growth, More specifically, they confirm the utility of BLI and ultrasound imaging as facile assays of the vascular disruption in solid tumors based on ATO as a model agent.     

超声造影与B型超声对人颈动脉内膜-中层厚度及斑块的诊断价值分析

摘要 目的：探讨超声造影（CEUS）与B型超声在诊断人颈动脉内膜-中层厚度（CIMT）及斑块中的临床应用价值。方法：选取2018年10月至2022年12月内蒙古自治区人民医院健康体检者142例,均行颈动脉B型超声和CEUS成像检查。记录左右侧颈动脉各分段点CIMT近壁和远壁值,然后取平均值。采用半定量的方法进行评分,以确定在B型超声和CEUS成像过程中的CIMT可视化。比较B型超声和CEUS成像技术对斑块检出的差异。根据CIMT平均值进行进一步分组,分析CIMT与亚临床左心功能障碍之间的关系。结果：在B型超声成像上,左右侧颈动脉CIMT远壁的可视化评分均明显高于CIMT近壁,差异有统计学意义（P＜0.05）;在CEUS成像上,左右侧颈动脉CIMT远壁的可视化评分均高于CIMT近壁,差异有统计学意义（P＜0.05）。与B型超声成像模式对比,在CEUS成像模式中左右侧颈动脉CIMT远壁和近壁的可视化评分均得到显著提高,差异有统计学意义（P＜0.05）。142例健康体检者中,B型超声总共检测出271个斑块,CEUS总共检测出293个斑块,斑块检出率组间比较差异有统计学意义（P＜0.05）。随着CIMT平均值的逐渐增大,LVM逐渐减小,LVGLS逐渐增大,差异有统计学意义（P＜0.05）。CIMT平均值的大小与LVEDD、LVESD和LVEF差异无统计学意义（P＞0.05）。结论：CEUS改善了CIMT的可视化,并能更好地检测出颈动脉斑块（主要为低回声斑块）,对预测心血管疾病的发生有一定临床价值。     

泌尿系造影联合彩色多普勒对小儿先天性肾积水的诊断价值评估

摘要 目的：探讨泌尿系造影联合彩色多普勒对小儿先天性肾积水的诊断价值。方法：选取2018年11月～2021年11月在本院治疗的88例先天性肾积水患儿为研究对象,所有患儿均完善静脉肾盂造影及彩色多普勒超声检查,以病理诊断结果为金标准,对比两种检查方法对小儿先天性肾积水的诊断价值。结果：彩色多普勒超声检查结果显示,肾积水轻度、中度、重度患儿分别为10例、39例、39例,不同病情程度患儿比较,重度组收缩期峰值速度（PSV）、舒张期最小流速（EDV）均低于中度组和轻度组,重度组血流阻力指数（RI）高于中度组和轻度组（P<0.05）,但轻度组与中度组PSV、EDV、RI比较差异无统计学意义（P>0.05）。与病理学诊断检查结果对比,彩色多普勒超声对中度、重度先天性肾积水患儿具有较高的诊断效能,其准确度分别为90.91%、93.18%,与病理诊断kappa值分别为0.795、0.862,具有较高的一致性;但对轻度肾积水诊断效能较低,kappa值为0.629,一致性一般。静脉肾盂造影对轻度先天性肾积水患儿具有较高的诊断效能,准确度为96.59%,与病理诊断kappa值为0.824,具有较高的一致性;但对中度、重度肾积水诊断效能较低,kappa值分别为0.583、0.565,一致性一般。彩色多普勒超声联合静脉肾盂造影诊断准确率高达94.32%,明显高于两检查方法单独应用（P<0.05）。结论：不同病情程度的先天性肾积水患儿具有不同超声征象,彩色多普勒超声对中、重度肾积水患儿具有较好的诊断价值,而静脉肾盂造影诊断轻度肾积水患儿的效能较好,将二者联合可提高对先天性肾积水的诊断准确率。     

Medical and non-medical protection standards for ultrasound and infrasound

Protection from inappropriate or hazardous exposure to ultrasound is controlled through international standards and national regulations. IEC standard 60601 part 1 establishes requirements for the mechanical, electrical, chemical and thermal safety for all electro-medical equipment. The associated part 2 standard for diagnostic medical ultrasonic equipment sets no upper limits on ultrasonic exposure. Instead, safety indices are defined that are intended to advise users on the degree of thermal and mechanical hazard. At present the display of these safety indices satisfies regulatory requirements in both the USA and Europe. Nevertheless there are reservations about the effectiveness of this approach to protection management. In the USA, there are national regulatory limits on diagnostic exposure, based on acoustic output from clinical equipment in use over 20 years ago. The IEC 60601 part 2 standard for therapeutic equipment sets 3 W cm⁻² as the limit on acoustic intensity. Transducer surface temperature is controlled for both diagnostic and therapy devices.

For airborne ultrasound, interim guidelines on limits of human exposure published by the IRPA are now 2 decades old. A limit on sound pressure level of 100 dB for the general population is recommended. The absence of protection standards for infrasound relates to difficulties in measurement at these low frequencies.     

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice

Cardiac troponin I (TnI) knockout mice exhibit a phenotype of sudden death at 17-18 days after birth due to a progressive loss of TnI. The objective of this study was to gain insight into the physiological consequences of TnI depletion and the cause of death in these mice. Cardiac function was monitored serially between 12 and 17 days of age by using high-resolution ultrasonic imaging and Doppler echocardiography. Two-dimensional B-mode and anatomical M-mode imaging and Doppler echocardiography were performed using a high-frequency ( approximately 20-45 MHz) ultrasound imaging system on homozygous cardiac TnI mutant mice (cTnI(-/-)) and wild-type littermates. On day 12, cTnI(-/-) mice were indistinguishable from wild-type mice in terms of heart rate, atrial and LV (LV) chamber dimensions, LV posterior wall thickness, and body weight. By days 16 through 17, wild-type mice showed up to a 40% increase in chamber dimensions due to normal growth, whereas cTnI(-/-) mice showed increases in atrial dimensions of up to 97% but decreases in ventricular dimensions of up to 70%. Mitral Doppler analysis revealed prolonged isovolumic relaxation time and pronounced inversion of the mitral E/A ratio (early ventricular filling wave-to-late atrial contraction filling wave) only in cTnI(-/-) mice indicative of impaired LV relaxation. cTnI(-/-) mouse hearts showed clear signs of failure on day 17, characterized by >50% declines in cardiac output, ejection fraction, and fractional shortening. B-mode echocardiography showed a profoundly narrowed tube-like LV and enlarged atria at this time. Our data are consistent with TnI deficiency causing impaired LV relaxation, which leads to diastolic heart failure in this model.     

The usefulness of contrast-enhanced sonography in the differential diagnostic of adrenal tumors

INTRODUCTION: The occurrence of gland tumors causes significant clinical problem. Non hormone-secreting tumors provide the most complicated diagnostic difficulties. The application of contrast-enhanced sonography could improve the vessels visualization and point out characteristic features of benign and malignant changes. The authors believe that this new method make possible the differential adrenal tumor diagnostic process more precise and increase the specificity of ultrasonography in the recognition of benign and malignant tumors. The aim of this study was to define the usefulness of contrasting agent Levovist in differential diagnostics of adrenal tumors and its influence on sensitivity and specificity of ultrasound examination and to establish patients qualification criteria for surgical procedures. MATERIAL AND METHODS: Ultrasound examinations were made with the use of digital devise by GE Voluson 740, probe 4-6 mHz with Doppler options and volumetric probe 3D according to the following protocol: 26 patients with recognized adrenal tumor were qualified for the examination. Patients in the first stage of tumor vascularization had Doppler examination with color (CD) and power Doppler (PD). Three-dimensional ultrasonography was used to improve visualization of vascularization. In the final phase of the examination the patients were administrated of Levovist in the recommended by the producer dose: 2.5 g in the concentration of 400 mg/l. RESULTS: 26 cases of adrenal gland tumours were subjected to analysis. In standard ultrasonographic examination focal changes in 25 patients were hipoechogenic focuses and in one case the focus was hyperechogenic. Heterogeneity of focuses was observed in 16 cases. In Doppler examination with color (CD) and power Doppler (PD) vascular blood flow was revealed within 12. After using contrasting agent Levovist vascular blood flow was achieved in 4 additional cases, which constituted 61%. CONCLUSIONS: 1. 3D ultrasound could be useful in cases of big adrenal tumors--over 3 cm diameter after application of ultrasound contrast agents. 2. The use of Levovist in Doppler examination improves the visualization of tumor vascularization. However, it is impossible to differentiate benign from malignant tumors unequivocally.     

彩色多普勒超声诊断子宫肉瘤的价值

目的探讨彩色多普勒超声对子宫肉瘤的诊断与鉴别诊断的价值。方法回顾性分析19例子宫肉瘤的声像图表现及多普勒血流频谱特点与手术及病理结果进行对照。结果子宫肉瘤的二维声像图表现分为四类：子宫肌层实性占位（4例）;子宫肌层囊实性占位（9例）;子宫内膜占位（4例）;宫颈占位（2例）。血流特点是肿瘤表面和内部以血流丰富型为主（15／19）,动脉阻力指数较低,15例RI平均值0．66。结论子宫肉瘤的声像图和血流多普勒显示具有特征性表现,超声检查对子宫肉瘤的早期发现、早期诊断及鉴别诊断能为临床提供重要帮助。     

Evaluation of ultrasonography effectiveness in prostate cancer detection

The database of examining 624 patients aged 49-85 were analyzed to define the diagnostic effectiveness of gray-scale, color and power Doppler transrectal ultrasonography (TRUS). Among them there are 473 (75.8%) cancer patients and 151 (24.2%) benign prostate diseases patients. All the patients underwent a transrectal ultrasound examination with multifocal biopsy. The gray-scale, color and power Doppler transrectal ultrasound examination has the diagnostic accuracy of 75,3%. At this the effectiveness of the method increases with the Gleason sum growing.     

基于动态聚焦的声聚焦光声内窥成像算法研究

目的 声聚焦光声内窥成像具有成像深度大的优点,是一种非常有前景的功能成像技术,该技术被广泛应用于直肠、食道等内窥成像中。声聚焦光声内窥成像通常采用基于单个聚焦超声传感器的侧向扫描方式,同时采用传统的B扫描方法进行重建,会大大降低图像质量。为了获得高质量的图像,本文提出了几种动态聚焦的声聚焦光声内窥成像算法。方法 本文使用几种动态聚焦算法进行了数值仿真,并搭建系统进行了仿体实验验证,从横向分辨率和信噪比等多方面比较了各算法在动态聚焦中的成像效果。结果 相比B扫描方法,动态聚焦后的图像在离焦区域的横向分辨率与信噪比方面都有提升,仿真模拟中最高可将离焦区域的成像目标分辨率提升约26倍,其信噪比经动态聚焦后最高可提高2.3倍左右,实验中的远距离点目标经动态聚焦重建后分辨率提升3～6倍。结论 整体而言,基于时空响应的算法和合成孔径聚焦重建算法是在实验条件下更为适用的算法。本工作对后续的声聚焦光声内窥成像的设计具有指导意义。     

超声技术鉴别子宫肌瘤和子宫腺肌病

子宫肌瘤和腺肌病的准确鉴别在妇科临床诊治中有十分重要的意义,各种鉴别诊断技术中,超声技术因其无损性、简便性而成为常规的一种方法。超声成像技术是其中较为成熟的方法。在综述B型成像、彩色血流成像结合脉冲多普勒、彩色血流功率成像和三维彩色功率成像等四种超声成像技术鉴别子宫肌瘤和子宫腺肌病情况的基础上,介绍了两种新的超声鉴别方法：超声弹性检测技术、基于其他声学特征参数检测的组织定征技术。