三维超声联合TUI和VCI技术诊断肝实性肿瘤

目的 探讨三维超声联合断层超声成像(TUI)和容积空间对比成像(VCI)技术诊断肝实性肿瘤的价值。方法 对50个肝实性肿瘤病灶分别进行二维超声与三维超声联合TUI、VCI检查,评价两种技术对病灶的显示能力。以手术或穿刺活检的病理结果作为金标准,对二者诊断的准确率进行比较,对比分析两种方法对肝恶性肿瘤诊断的敏感度、特异度、准确率、阳性预测值、阴性预测值。结果 二维超声诊断与病理诊断的符合率为68.00%(34/50),三维超声联合TUI、VCI技术诊断与病理诊断的符合率为90.00%(45/50,P<0.05);三维超声联合TUI、VCI技术诊断肝恶性肿瘤的敏感度为91.67%(33/36)、特异度为85.71%(12/14)、准确率为90.00%(45/50)、阳性预测值为94.29%(33/35)、阴性预测值为80.00%(12/15),其敏感度、准确率、阴性预测值与二维超声诊断肝恶性肿瘤比较差异有统计学意义(P均<0.05)。结论 三维超声联合TUI、VCI技术能够提供更全面、更丰富的诊断信息,对定性诊断肝脏肿瘤有较高的临床应用价值。     

Three-dimensional extended field-of-view ultrasound

Three-dimensional (3-D) extended field-of-view ultrasound creates a mosaic view from a set of volumes acquired from a dedicated 3-D ultrasound machine combined with a position tracker. A simple compounding technique can be used to combine the volumes together using only the position measurements, but some misalignment remains. Two different registration methods were developed to correct these errors in the overlapping regions. The first method divides the overlap into smaller blocks and warps the blocks to best align the features. The second method is similar, but uses rigid body registration of the blocks. Experiments in vitro and in vivo showed that block-based registration with warping produced the most reproducible results and the greatest increase in similarity among the overlapping regions. It also produced the best reconstruction accuracy, with a mean distance error of 0.4 mm measured across 101.78 mm in a phantom, representing 0.4% error.     

超声影像学网络教学探讨

从超声影像学网络教学模式探讨出发,概述目前国内超声影像学学科特点和传统教学以及网络教学现状,分析现有教学模式存在的薄弱环节和制约因素,提出网络教学模式的改革措施及努力方向,以期提高资源利用率,提升超声影像学的教学质量。     

Accuracy of three-dimensional transvaginal ultrasound in uterus volume measurements; comparison with two-dimensional ultrasound

The purpose of this study was to document the accuracy of 3-D uterus volume and to compare it with 2-D measurements. Transvaginal ultrasound (US) examinations were performed in 48 consecutive patients before hysterectomy. The examinations were stored digitally on an internal disk drive for subsequent measurements in virtual organ computer-aided analysis (VOCAL) program. Immediately after the hysterectomy, the true volume was measured in a water bath. A total of 5 patients were excluded due to difficulty of identifying the borders of their uterus; 8 patients were excluded because of too large fibroids or diffuse hypertrophic enlargement of uterus (volume> 220 mL). Although the volumes estimated by the 3-D method were not significantly different (p = 0.126 first measurement, p = 0.561 second measurement), the volumes estimated by the 2-D method were significantly different (p = 0.005 first measurement, p = 0.012 second measurement). The mean error rates of the two 3-D volume measurements by the same observer were 7.4% and 7.9%, and they were 22.2% and 21.0% for the 2-D volume measurements. It may be concluded that the volume of the uterus can be measured more accurately by 3-D US than by 2-D US. (E-mail: cemil.yaman@akh.linz.at)     

超声分子影像学研究进展

随着超声分子探针技术的兴起,超声分子成像成为当前医学影像学研究的热点之一.分子探针的设计是超声分子成像研究的重点和先决条件.靶向超声微泡(球)造影剂在分子影像中的研究、应用,愈来愈受到关注,而多学科的融合使其具有更大的发展空间.     

Real-time 3-D contrast-enhanced transcranial ultrasound and aberration correction

Contrast-enhanced (CE) transcranial ultrasound (US) and reconstructed 3-D transcranial ultrasound have shown advantages over traditional methods in a variety of cerebrovascular diseases. We present the results from a novel ultrasound technique, namely real-time 3-D contrast-enhanced transcranial ultrasound. Using real-time 3-D (RT3D) ultrasound and microbubble contrast agent, we scanned 17 healthy volunteers via a single temporal window and nine via the suboccipital window and report our detection rates for the major cerebral vessels. In 71% of subjects, both of our observers identified the ipsilateral circle of Willis from the temporal window, and in 59% we imaged the entire circle of Willis. From the suboccipital window, both observers detected the entire vertebrobasilar circulation in 22% of subjects, and in 44%, the basilar artery. After performing phase aberration correction on one subject, we were able to increase the diagnostic value of the scan, detecting a vessel not present in the uncorrected scan. These preliminary results suggest that RT3D CE transcranial US and RT3D CE transcranial US with phase aberration correction have the potential to greatly impact the field of neurosonology. (E-mail: ni3@duke.edu).     

用于超声分子成像的聚乳酸-乙醇酸造影剂的研究进展

超声分子成像是基于靶向超声造影剂发展起来的一门新兴的影像技术,通过超声造影的方式反映细胞的病理生理变化,在分子水平上显示疾病发生、发展的过程。近年来,出现了多种用于超声分子成像的聚乳酸-乙醇酸造影剂。本文就这些新兴造影剂的制备方法和靶向设计做一综述。     

40-MHz annular array imaging of mouse embryos

Ultrasound biomicroscopy (UBM) has emerged as an important in vivo imaging approach for analyzing normal and genetically engineered mouse embryos. Current UBM systems use fixed-focus transducers, which are limited in depth-of-focus. Depending on the gestational age of the embryo, regions-of-interest in the image can extend well beyond the depth-of-focus for a fixed-focus transducer. This shortcoming makes it particularly problematic to analyze 3-D data sets and to generate accurate volumetric renderings of the mouse embryonic anatomy. To address this problem, we have developed a five-element, 40-MHz annular array transducer and a computer-controlled system to acquire and reconstruct fixed- and array-focused images of mouse embryos. Both qualitative and quantitative comparisons showed significant improvement with array-focusing, including an increase of 3 to 9 dB in signal-to-noise ratio and an increase of at least 2.5 mm in depth-of-focus. Volumetric-rendered images of brain ventricles demonstrated the clear superiority of array-focusing for 3-D analysis of mouse embryonic anatomy.     

超声分子成像的机制及研究现状

随着分子生物学的迅速发展以及疾病分子机制的逐步阐明,医学影像学已深入到细胞及分子水平.超声分子成像技术是医学分子影像学领域中重要组成部分,在当今分子影像学中占据重要地位.本文对其成像机制及研究现状进行综述.     

留学生超声影像学教学实践及体会

超声影像学教学对医学留学生培养具有重要作用,其全英文教学已引起广泛关注。在教学过程中需要针对超声影像学课程和留学生特点,做好充分教学准备工作,不断改进教学方法,才能提高教学质量。     

在细胞生物学教学中引入超声分子影像学概念的思考

细胞生物学是医学影像专业的重要基础课程,与多学科相互融会贯通,在细胞生物学教学过程中,可以引入超声分子影像学概念,以加强基础学科与专业学科的联系,拓宽学生视野,锻炼学生创新思维,提升教学效果.     

Reliability of 3-D ultrasound measurements of cervical lymph node volume

This study was undertaken to evaluate the reliability of three-dimensional (3-D) ultrasound in measuring cervical lymph node volume. Ultrasound examination of the neck was performed on 15 healthy subjects (eight men and seven women). For each subject, the volume of cervical lymph nodes was measured twice with 3-D ultrasound by two operators, to evaluate the reproducibility of measurements (interoperator variability). 3-D ultrasound measurements of cervical node volume were performed with and without using SonoCT and XRES imaging. Each 3-D data set was reviewed and remeasured by the operators to evaluate the repeatability of measurements (intra-operator variability). Results showed that the reproducibility and repeatability of 3-D ultrasound volumetric measurements of cervical nodes was improved when SonoCT and XRES imaging were used. There was a high repeatability of 3-D ultrasound measurements of cervical node volume (> 90%). A high reproducibility of measurements was found in the posterior triangle nodes (90.3% - 90.9%). When SonoCT and XRES imaging were used with the scanning, there was a high reproducibility for parotid node measurements (87.4%) and a satisfactory level of reproducibility for submental (61.8%), submandibular (69.3%) and upper cervical node (79%) measurements. 3-D ultrasound is a useful and reliable method in measuring cervical lymph node volume. However, further studies to improve the reproducibility of 3-D ultrasound measurements of submental, submandibular and upper cervical node volume are suggested.     

3-D measurement of body tissues based on ultrasound images with 3-D spatial information

In this study, we developed a new method to perform 3-D measurements between the recorded B-scans using the corresponding spatial location and orientation of each B-scan, without the need to create a 3-D volume. A portable ultrasound (US) scanner and an electromagnetic spatial locator attached to the US probe were used. During data collection, the US probe was moved over the region-of-interest. A small number of B-scans containing interesting anatomical information were captured from different body parts and displayed in a 3-D space with their corresponding locations recorded by the spatial locator. In the B-scan planes, the distance between any two points, as well as the angle between any two lines, could be calculated. In validation experiments, three distances and three angles of a custom-designed phantom were measured using this method. In comparison with the results measured by a micrometer, the mean error of distance measurement was −0.8 ± 1.7 mm (−2.3 ± 3.6%) and that of angle measurement was −0.3 ± 2.9° (−0.1 ± 4.1%). The lengths of the first metatarsals and the angles between the first metatarsals and the middle part of the tibias of three subjects were measured in vivo using magnetic resonance imaging (MRI) and the US method by two operators before and after MRI scanning. The overall percentage differences of the length and angle measurements were 0.8 ± 2.2% and 2.5 ± 3.6%, respectively. The results showed that this US method had good repeatability and reproducibility (interclass correlation coefficient values > 0.75). We expect that this new method could potentially provide a quick and effective approach for the 3-D measurement of soft tissues and bones in the musculoskeletal system.     

Validity of measuring distal vastus medialis muscle using rehabilitative ultrasound imaging versus magnetic resonance imaging

Objective quantification of muscle size can aid clinical assessment when treating musculoskeletal conditions. To date the gold standard of measuring muscle morphology is magnetic resonance imaging (MRI). However, there's a growing body of evidence validating rehabilitative ultrasound imaging (RUSI) against MRI.ObjectiveThis study aimed to validate RUSI against MRI for the linear measurements of the distal fibres of vastus medialis muscle in the thigh.Twelve healthy male participants were recruited from a local university population. The distal portion of their right vastus medialis was imaged with the participant in long-sitting, using MRI and RUSI whilst the leg was in extension and neutral hip rotation. Cross sectional area (CSA) and three linear measures were taken from the MRI and these were compared with the same linear measures from RUSI. Statistical analysis included comparison of MRI and RUSI measures using the paired t-test and intra-class correlation coefficients (ICC 3,1).Mean differences between the linear measures taken from the MRI and RUSI were −0.5 mm to 2.9 mm (95% confidence intervals −0.6–8.3 mm), which were not statistically different (p > 0.05) and were highly correlated (ICCs 3,1 0.84–0.94). Correlations between the three linear measurements and muscle CSA ranged from r = 0.23 to 0.87, the greatest being muscle thickness. Multiplying the linear measures did not improve the correlation of 0.87 found for muscle thickness.Linear measures of vastus medialis depth made using RUSI were shown to be as valid as using MRI. Muscle thickness measures using RUSI could be used within an objective assessment of this muscle.     

Robot-assisted ultrasound imaging: Overview and development of a parallel telerobotic system

Ultrasound imaging is frequently used in medicine. The quality of ultrasound images is often dependent on the skill of the sonographer. Several researchers have proposed robotic systems to aid in ultrasound image acquisition. In this paper we first provide a short overview of robot-assisted ultrasound imaging (US). We categorize robot-assisted US imaging systems into three approaches: autonomous US imaging, teleoperated US imaging, and human-robot cooperation. For each approach several systems are introduced and briefly discussed. We then describe a compact six degree of freedom parallel mechanism telerobotic system for ultrasound imaging developed by our research team. The long-term goal of this work is to enable remote ultrasound scanning through teleoperation. This parallel mechanism allows for both translation and rotation of an ultrasound probe mounted on the top plate along with force control. Our experimental results confirmed good mechanical system performance with a positioning error of < 1 mm. Phantom experiments by a radiologist showed promising results with good image quality.     

超声分子显像与治疗及设备的研究

近年来,随着医学影像技术的发展,超声分子成像成为当前医学影像学研究的热点之一,其中超声分子探针的设计是分子成像研究的重点和先决条件。靶向超声微泡(球)造影剂在超声分子显像及治疗中的研究和应用愈来愈受到人们的关注,而多学科的融合使其具有更大的发展空间。将超声分子成像设备、超声微泡(球)触发装置、超声分子成像监控与超声分子探针有机结合的"低功率超声分子显像与治疗系统",有望实现超声分子显像及精细、适形、高效的药物体内定位递送、定量控释和疗效评价一体化,为疾病的超声分子显像诊断与治疗提供创新的、适合多学科使用的新技术和科研平台。     

Analysis of refractive artifacts by reconstructed three-dimensional ultrasound imaging

Purpose Refractive artifacts are frequently encountered in clinical settings, and they have been analyzed on the basis of conventional two-dimensional (2-D) ultrasound (US) images, but this method is restricted to monoplane data and is limited by its inability to assess the three-dimensional (3-D) structure of refractive artifacts. The aim of this study was to evaluate the role of reconstructed 3-D US images in the analysis of refractive artifacts. Methods The following representative refractive artifacts were analyzed on the basis of reconstructed 3-D US images: (a) a distorted image of a fine tube behind a cyst (balloon); (b) a deformed image of the bottom of a balloon; and (c) a duplication artifact due to the acoustic lens effect. Results (a) A tube was imaged as a fine echogenic line with two points of sudden interruption, unlike a curved needle, which was imaged without interruption. (b) 3-D US allowed us to visualize the mode of deformity in the image of the bottom of a fluid-filled balloon in a water bath. When the acoustic velocity in the fluid was greater than that in the surrounding water, the bottom of the balloon appeared to be shrunken. When the acoustic velocity in the fluid was less than that in the surrounding water, the bottom of the balloon appeared to be swollen. (c) When we placed two pieces of white chicken meat in front of a fine needle, the needle was duplicated in the resulting image. In this case, the needle appeared to be vague and fuzzy. In this case, 3-D US did not add further information to the 2-D images. Conclusions Our study suggests that reconstructed 3-D US images provide a better understanding of the mode of refractive artifacts than do 2-D US images.     

Evaluation of normal and abnormal hyoid bone movement during swallowing by use of ultrasound duplex-Doppler imaging

We developed a new method to analyze normal and abnormal movements of the hyoid muscular region as an indicator of hyoid bone motion during swallowing using ultrasound duplex-Doppler imaging. Hyoid bone motion can be monitored by studying the Doppler shift spectra and B-mode images produced by ultrasound duplex imaging of the hyoid region muscular attachments. We can accurately determine swallowing duration and trajectory of hyoid bone movement. This procedure can assist in discriminating between normal and abnormal movements of the hyoid bone and the surrounding muscles during swallowing. This method appears to be a highly consistent measure. We suggest that Doppler spectrum analysis can be used for defining hyoid position and displaying accurate movement, which may be useful in the diagnosis of swallowing disorders.     

Real-time 3-d intracranial ultrasound with an endoscopic matrix array transducer

A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting and 252 receive channels placed in a regular pattern in the array. The operating frequency is 4.5 MHz with a -6 dB bandwidth of 30%. The transducer is fabricated on a 10-layer flexible circuit from Microconnex (Snoqualmie, WA, USA). The purpose of this study is to evaluate the clinical feasibility of real-time 3-D intracranial ultrasound with this device. The Volumetrics Medical Imaging (Durham, NC, USA) 3-D scanner was used to obtain images in a canine model. A transcalvarial acoustic window was created under general anesthesia in the animal laboratory by placing a 10-mm burr hole in the high parietal calvarium of a 50-kg canine subject. The burr-hole was placed in a left parasagittal location to avoid the sagittal sinus, and the transducer was placed against the intact dura mater for ultrasound imaging. Images of the lateral ventricles were produced, including real-time 3-D guidance of a needle puncture of one ventricle. In a second canine subject, contrast-enhanced 3-D Doppler color flow images were made of the cerebral vessels including the complete Circle of Willis. Clinical applications may include real-time 3-D guidance of cerebrospinal fluid extraction from the lateral ventricles and bedside evaluation of critically ill patients where computed tomography and magnetic resonance imaging techniques are unavailable.     

On ultrasound imaging for guided screw insertion in spinal fusion surgery

Spinal fusion surgery generally involves the insertion of screws in the pedicle, a three-dimensional (3-D) process that requires great skill if serious consequences are to be avoided. This article describes an image guidance technique based on generating B?mode images from within a small bore hole in the pedicle’s trabecular bone. The purpose is to determine the viability and safety of the hole placement for subsequent insertion of the screw. Toward this end, this article endeavours to understand the factors that govern B-mode image quality. Specifically, the results of numerical simulations on the effects of transducer frequency and bone volume on image quality are presented along with demonstrations of B-mode image formation obtained in vitro on human pedicles using a 3.2 MHz probe. The results of the numerical simulations suggest that high frequency and high bone volume generally reduce the image quality. The in vitro experiments showed that the trabecular and cortical bone can be detected in the B-mode images. (E-mail: cobbold@ecf.utoronto.ca)