Reliability of measuring sciatic and tibial nerve movement with diagnostic ultrasound during a neural mobilisation technique

Diagnostic ultrasound provides a technique whereby real-time, in vivo analysis of peripheral nerve movement is possible. This study measured sciatic nerve movement during a "slider" neural mobilisation technique (ankle dorsiflexion/plantar flexion and cervical extension/flexion). Transverse and longitudinal movement was assessed from still ultrasound images and video sequences by using frame-by-frame cross-correlation software. Sciatic nerve movement was recorded in the transverse and longitudinal planes. For transverse movement, at the posterior midthigh (PMT) the mean value of lateral sciatic nerve movement was 3.54 mm (standard error of measurement [SEM] +/- 1.18 mm) compared with anterior-posterior/vertical (AP) movement of 1.61 mm (SEM +/- 0.78 mm). At the popliteal crease (PC) scanning location, lateral movement was 6.62 mm (SEM +/- 1.10 mm) compared with AP movement of 3.26 mm (SEM +/- 0.99 mm). Mean longitudinal sciatic nerve movement at the PMT was 3.47 mm (SEM +/- 0.79 mm; n = 27) compared with the PC of 5.22 mm (SEM +/- 0.05 mm; n = 3). The reliability of ultrasound measurement of transverse sciatic nerve movement was fair to excellent (Intraclass correlation coefficient [ICC] = 0.39-0.76) compared with excellent (ICC = 0.75) for analysis of longitudinal movement. Diagnostic ultrasound presents a reliable, noninvasive, real-time, in vivo method for analysis of sciatic nerve movement.     

Pictorial essay: Ultrasound of tumours and tumour-like lesions of peripheral nerves

High-resolution ultrasound is an excellent diagnostic modality for visualising peripheral nerves and differentiate tumours of the peripheral nerve. With high-frequency transducers (5-15 MHz), peripheral nerves can be visualised, the hypoechoic nerve fascicles, the surrounding tissue and tumourous lesions including the relation to their nerve of origin can be evaluated. By using colour Doppler sonography (CDS), it is possible to detect and assess vascularisation of tumours of the nerve. We present sonographic features of common and uncommon benign and malignant tumours of the peripheral nerve.     

周围神经干的超声定位

目的观察周围神经干超声声像图结构特征,并验证超声引导穿刺定位神经干的准确性。方法对20例志愿者行肌皮神经、坐骨神经、胫神经超声检查,对其中6位志愿者行肌皮神经穿刺定位,5位志愿者行胫神经穿刺定位,9例志愿者行坐骨神经穿刺定位。结果20例志愿者均有效显示相应神经干,肌皮神经、胫神经及坐骨神经显示率为100%。横断面上周围神经干内部呈低回声,周边见膜状高回声的筛孔状结构,纵切面上表现为中等回声,内见线性平行回声的管状结构。6例肌皮神经及5例胫神经超声引导穿刺定位均一次性成功,电刺激验证神经定位准确,引起相应肌肉收缩的电流强度分别为0～0.4mA及0.2～1.0mA,9例坐骨神经超声引导穿刺定位一次性成功7例,二次穿刺定位成功2例,电刺激验证神经定位准确,引起相应肌肉收缩的电流强度分别为0.2～1.4mA。结论超声能清晰显示周围神经干的走行及结构特征,并能准确定位。     

高频超声在各细小神经中的临床应用

目前CT、MRI等影像技术难以实时动态地对细小周围神经进行观测。随着超声技术的快速进步，超声分辨率不断提高，使用高频超声对一些细小神经进行观察成为可能。细小神经超声显像逐渐被用于多种疾病的诊断与鉴别诊断，在临床诊疗中体现出日益重要的作用。通过超声显像确定细小神经的解剖位置可以为精准的神经阻滞提供引导，此外，神经的横截面积、回声及血流信号等超声测量参数的变化可为多种疾病的诊断及疗效评估提供参考依据。本文就高频超声对各个细小神经显像和相关诊断及神经阻滞中的应用现状及进展进行综述。     

Ultrasonography of peripheral nerves.

With recent improvements in ultrasound (US) imaging equipment and refinements in scanning technique, an increasing number of peripheral nerves and related pathologic conditions can be identified. US imaging can support clinical and electrophysiologic testing for detection of nerve abnormalities caused by trauma, tumors, and a variety of nonneoplastic conditions, including entrapment neuropathies. This article addresses the normal US appearance of peripheral nerves and discusses the potential role of US nerve imaging in specific clinical settings. A series of US images of diverse pathologic processes involving peripheral nerves is presented.     

高频超声诊断四肢外周神经损伤的临床价值

目的探讨高频超声在外周神经损伤中的诊断价值。方法高频超声检查30例健康志愿者,了解正常外周神经超声图像的基础上,对临床40例外周神经损伤于术前行超声检查,并用术中所见及病理学检测结果证实超声诊断价值。结果正常外周神经纵切声像图为多条平行线性回声的束状结构。外周神经完全断裂,可见束状结构连续性中断,近端形成神经瘤,外周神经肿胀粘连,显示神经增粗,束状结构回声界限模糊不清。卡压性损伤可见神经变细,内部呈低回声改变。超声与术中所见及病理检测结果的符合率达87．5％。结论高频超声检查对外周神经损伤有较好的诊断价值,对临床治疗和选择手术方案有重要指导意义。     

Doppler ultrasound in noninvasive cardiac evaluation. The growing range of applications

Ultrasound is of proven clinical utility for imaging cardiac structures. Doppler ultrasonic techniques can be used with or without echocardiography for noninvasive hemodynamic studies. The usefulness of Doppler ultrasonic techniques in the noninvasive laboratory has been shown recently at the Massachusetts General Hospital, Boston. In 61 of 100 consecutive patients in a prospective study, Doppler ultrasound provided clinical information that could not be obtained with echocardiographic studies alone. The advantages of this technique for noninvasive cardiac studies are now being recognized in the general medical community. The results of ongoing clinical investigations will help define the role of Doppler echocardiography as a clinically useful diagnostic tool for cardiac evaluation.     

高频超声诊断周围神经内、外囊肿致神经卡压的临床价值

目的 探讨高频超声在诊断周围神经内、外囊肿导致神经卡压综合征中的临床价值。方法 周围神经囊肿患者27例，使用高频超声扫查病变神经，观察神经内、外囊肿致周围神经损伤声像图表现。并与肌电图、MRI进行比较，以手术术中探查为标准。结果 27例患者超声诊断神经内囊肿12例，主要超声表现神经内条带状囊性结节，上下累及神经范围较长，正常神经束膜受压移位；神经外囊肿15例，主要超声表现为神经卡压变形，近心端及远心端内径明显增粗，束状结构或筛网状结构不清或消失，囊肿与神经分界清晰。与手术术中所见符合的为24例。肌电图结果显示23例为阳性表现，主要为神经传导速度及波幅明显减低。3例患者行MRI检查，检查结果显示神经走行区域囊状信号影，病变与神经分界不清。结论 高频超声可对神经囊肿提供形态学依据，可与肌电图的电生理特点结合，为临床提供更多的影像学支持。     

Estimation of aortic and pulmonary blood flow in a paediatric population using Doppler ultrasound: an in-vitro study

The noninvasive measurement of blood flow using ultrasound has been attempted by numerous workers. In order to evaluate the technique of duplex scanning applied to the problem of noninvasive assessment of aortic and pulmonary blood flow in a paediatric population with ventricular septal defect, we attempted an in-vitro simulation of these flow conditions. The factors which have been considered in the design of the apparatus include the availability of a range of tube diameters, an aortic-"like" waveform, laminar flow, variable downstream peripheral resistance, a compliance factor and viscosity of the flow medium. The ultrasound probe beam characteristics, sample volume size and shape were also determined. From the results of the beam plots it was apparent that the region of sensitivity of the CW Doppler probes were inappropriate for the measurement of blood flow in neonates. In order to simulate physiological parameters in a paediatric population as closely as possible, five tubes of diameters ranging from 9-18 mm were used, in each tube a range of flow values from 0.8 L min-1 to 5 L min-1 were measured. The flow values were measured by both "bucket and stopwatch" and duplex scanner for both steady and pulsatile flow conditions. The results are presented as correlations between the direct and noninvasive pulsed Doppler assessment of flow measurement and are in the range 0.92-0.99 significant at p less than .001. A discussion of the reliability of flow measurements made using a conventional duplex scanner is given.     

Angle-independent motion measurement by correlation of ultrasound signals assessed with a single circular-shaped transducer

In medicine, pulsed ultrasound is a widespread noninvasive technique that measures motion in the direction of the ultrasound beam, i.e., axial motion. The magnitude of the actual motion can be determined only if the angle between the ultrasound beam and the direction of motion (transducer-to-motion angle) is known. For blood flow measurements, current pulsed ultrasound systems assume this angle to be equal to the angle between the ultrasound beam and the longitudinal direction of the vessel, as can be estimated from a two-dimensional brightness-mode (B-mode) image that is obtained prior to the blood flow measurement. For tissue motion measurements, current pulsed ultrasound systems are mostly unable to determine the transducer-to-motion angle. Recently, a model has been derived for the correlation of(analytic) radiofrequency (rf) signals, assessed with a circular-shaped ultrasound transducer along the same line of observation. In the present paper, this model is used to derive estimators, requiring only the calculation of a few correlation coefficients, for the motion components (axial, lateral and actual) and for some of the signal parameters (center frequency, bandwidth and signal-to-noise ratio) of the assessed rf signals. The transducer-to-motion angle can be derived from the estimated motion components. For the evaluation of the estimators, rf signals were acquired with a motion-controlled experimental arrangement. The results of the evaluation study show that the transducer-to-motion angle can be estimated with a mean standard deviation of less than 2 degrees.     

高频超声在细小神经诊疗中的临床应用

目前CT、MRI等影像技术均难以对细小周围神经进行实时动态观察。随着超声技术的快速发展,超声分辨率不断提高,应用高频超声对一些细小神经进行观察成为可能,并逐渐应用于多种疾病的诊断与鉴别诊断。通过超声显像确定细小神经的解剖位置可以精准地引导神经阻滞,通过观测神经的横截面积、回声及血流信号等参数的变化,可为多种疾病的诊断及疗效评估提供参考依据。本文就高频超声对各细小神经显像和相关诊断,以及其在神经阻滞中的应用现状进行综述。     

Noninvasive Doppler assessment of renal artery stenosis and hemodynamics

We present a review of ultrasonic Doppler methods (duplex scanning) used in the noninvasive assessment of renal artery stenosis and hemodynamics. The clinically successful applications of ultrasonic Doppler methods to the noninvasive assessment of the peripheral and cerebral vasculatures have prompted investigators to apply these methods to the renal artery. Various Doppler criteria for the diagnosis of renal artery stenosis have given sensitivities and specificities that range from 31% to 91% and 88% to 100%, respectively. Furthermore, estimates of renal vascular flows and resistances can be made in echogenic subjects. The technical success rate of the method is operator dependent, consequently, reliable duplex scanning of the renal arteries may be limited to experienced ultrasound laboratories.     

The use of train of four monitoring for clinical evaluation of the axillary brachial plexus block

The axillary approach of brachial plexus anesthesia is the most commonly used technique for forearm and hand surgery. Dynamometer is known as objective test for the clinical assessment of motor block of the nerves in brachial plexus block. However, the use of this device may not always be practical in operating room. The train-of-four (TOF) test is a non-invasive peripheral nerve stimulator that shows the level of motor block of muscle relaxants. The aim of the study is to investigate the use of TOF testing as a peripheral nerve stimulator for objective clinical evaluation of motor block at axillary brachial plexus block. 44 patients were randomized according to the development of partial or complete motor in the axillary brachial plexus block. The nerves were selectively localized by nerve stimulation and ultrasound guidance. After obtaining an appropriate peripheral motor response, predetermined volumes of bupivacaine were selectively injected to the 4 nerves. Sensory, motor block levels and TOF values were measured at 10th, 20th, 30th minutes immediately after the axillary brachial plexus block. TOF values were gradually decreased and significant difference was observed between the development of a complete and partial motor block at 30th minute. TOF values were also significantly less in patients of complete sensory block than the patients of partial sensory block at 30th minute. The use of TOF monitoring may be beneficial to assess the objective clinical effect of motor block in the patients with axillary brachial plexus nerve block.     

Applications of Transcranial Color‐Coded Sonography in the Emergency Department

Transcranial color‐coded Doppler sonography is a noninvasive bedside ultrasound application that combines both imaging of parenchymal structures and Doppler assessment of intracranial vessels. It may aid in rapid diagnoses and treatment decision making of patients with intracranial emergencies in point‐of‐care settings. This pictorial essay illustrates the technical aspects and emergency department applications of transcranial color‐coded Doppler sonography, and provides some rationale for implementation of this technique into the emergency department practice.     

Ultrasound of the nerves of the knee region: Technique of examination and normal US appearance

The diagnosis of disorders of the peripheral nerves (PN) has traditionally been based on clinical and electrophysiological data since nerve tissue cannot be visualized on standard radiographs. More recently, however, nerve structures have been evaluated with magnetic resonance imaging (MRI) and ultrasound (US). The former modality is expensive and not available in all institutions. There are also some contraindications to its use, and the assessment of long nerves can be time-consuming since different coils must be used. Thanks to recent advances in sonographic software and hardware, US can now be used for in-depth assessment of the PN of the upper and lower limbs.Most knee disorders involve lesions to the cruciate ligaments and/or the menisci, which are difficult to evaluate with US. However, similar symptoms may be caused by compression of one or more nerves in the knee region or intrinsic disorders involving these structures. Because of their superficial positions, the nerves around the knee can be clearly visualized with US. A thorough knowledge of the normal anatomy of this region and a careful scanning technique are essential for a successful diagnostic US examination. In this article, we will review the normal gross and microscopic anatomy of the nerves in the knee region, the US technique used for their examination, and their normal US appearance.     

Aortic compliance measurements using doppler ultrasound: In vivo biochemical correlates

A noninvasive Doppler ultrasound technique for the assessment of aortic compliance based on the in vivo measurement of pulse wave velocity along the thoraco-abdominal aortic pathway is described. An approach for correcting for the effect of blood pressure on aortic distensibility is considered. The derivation of an index of intrinsic distensibility, Cp, which is independent of blood pressure, is provided and applied to data collected from normal, healthy volunteers. Overviews are provided of studies utilising the technique to determine aortic compliance in medical disorders, which are known to predispose to premature cardiovascular disease, such as diabetes mellitus, familial hypercholesterolaemia and growth hormone deficiency. The significance of correlations between in vivo aortic compliance measurements and plasma concentrations of total cholesterol, low-density-lipoprotein cholesterol, high-density-lipoprotein cholesterol and insulin-like growth factor-I are discussed. It is proposed that the measurement of aortic compliance in normal, healthy individuals may potentially be a useful in vivo research tool for investigating the effects of biochemical factors on the biophysical properties of the aortic wall. Furthermore, we believe that the routine measurement of blood pressure-corrected aortic distensibility may prove a useful, noninvasive clinical tool for assessing patients' susceptibility to atherosclerosis, as well as for monitoring their response to therapeutic interventions.     

Repeatability of measuring sciatic nerve excursion during a modified passive straight leg raise test with ultrasound imaging

The purpose of this study was to establish the reliability of a frame-by-frame cross correlation method of assessing longitudinal sciatic nerve excursion motion using real time ultrasound imaging during a modified passive straight leg raise (SLR) test. Eighteen asymptomatic participants (age range 19–68 years) lay on their sides on a purpose made jig and the sciatic nerve in the posterior thigh was imaged during knee extension at 30° and then 60° of hip flexion (HF). Participants were re-tested ≥48 h later. The ultrasound images were analysed off-line using cross correlation software. Results demonstrated excellent repeatability of in vivo sciatic nerve excursion during a modified SLR (HF30° ICC 0.92, CI 0.79–0.97, SEM 0.69; HF60° ICC 0.96, CI 0.89–0.99, SEM 0.87). The authors also identify points of good practise to ensure an accurate as possible measurement of nerve excursion using this method. These include breaking down larger movements into sub-components, visually tracking the moving nerve during the tracking procedure, and ensuring the optimal image is captured prior to analysis. The use of ultrasound imaging in lower limb nerve dysfunction will enhance the understanding of how nerves move in vivo during neurodynamic testing, as well as being able to identify possible alteration to nerve movements in patients with neuropathic pain states.     

Ultrasound and Anatomical Study of Accessing the Nerves in the Knee by Fascial Planes

The fascia is an undifferentiated mesenchymal tissue related to the peripheral nerves. Both can be identified by ultrasound, which is useful when performing peripheral nerve blocks. However, there is no unanimity about the approaching point of each nerve, nor is there a consensus on how to name the appropriate infiltration zone, although the paraneural zone is frequently mentioned. The aims of this study were to determine if ultrasound is accurate for identifying the fascial planes and the paraneural space of the nerves in the knee, infiltrating them, and achieving a correct anatomical diffusion, as well as for establishing access routes to avoid intraneural infiltration. The study was performed in 16 cryopreserved lower extremities of the dissection room of the Faculty of Medicine and Health Sciences, University of Barcelona. Nerves of the knee were injected with colorant guided by ultrasound after they were visualized. Correct location of the nerves by ultrasound was achieved in 98.75% of the cases, correct visualization of the needle by ultrasound in 82.5%, the hypoechogenic image around the nerve after infiltration in 82.5%, and a correct paraneural infiltration in 76.25% of cases. With these results, we can conclude that high‐definition ultrasound enables location of the peripheral nerves and adjacent structures as well as the fasciae that surround them, and therefore allows performance of infiltrations in the paraneural spaces.     

超声与神经阻滞

高频超声可清晰地显示外周神外,用超声引导行外周神经阻滞能更好地减少操作的盲目性并提高成功率。本文就国外对外周神经的超声影像学研究,超声引导外周神经阻滞技术的临床应用和评价作一综述。     

彩色多普勒超声和磁共振在门静脉系血流测定的应用

目的　进行彩色多普勒超声和磁共振血管造影在门静脉系血流量测定方面的对比。方法　用彩色多普勒超声(CDUS)和二维相位对比磁共振 ( 2D PCMR)测定门静脉高压症者门静脉系统血流量。结果　CDUS与 2D PCMR在门静脉系统血流量的测定无显著差别。结论　CDUS和 2D PCMR都为一种无创检查 ,但CDUS价格低廉 ,可作为门静脉高压症术前首选检查。