The purpose of this study was to evaluate and compare the effect of the variable factors of wire on the elastic properties of looped rectangular wire. Five variable factors were presented - material(Hi-T, blue Elgiloy), wire size(.016" x .022", .018" x .025"), loop length(15mm, 20mm), loop configuration(open loop, closed loop), gabling (non-gable, gable). So, the total 256 specimens were divided into 32 groups, and each of those was pulled on Instron testing machine. The load-deflection curve of each wire was obtained, from which force, range in elastic limit, and stiffness were computed and analyzed statistically. The results were obtained as follows: 1. All of the variable factors - wire material, size, loop length, loop configuration, and gabling - took a significant effect on load-deflection rate of looped wire. 2. The force at elastic limit was the smallest in the group of Hi-T, .0l6"x.022", 20mm loop length, open loop, non-gable, and the largest in the group of blue Elgiloy, .018"x.025", 15mm loop length, closed loop, non-gable. 3. The range at elastic limit was the smallest in the group of Hi-T, .0l8"x.025", 15mm loop length, open loop, non-gable, and the largest in the group of HI-T, .016"x.022", 20mm loop length, closed loop, gable. 4. Loop configuration and loop length were the most effective factors on the elastic properties of looped wires, and gabling was the least effective.
Elasticity

No abstract available.
Elasticity Imaging Techniques ; Elasticity ; Tendons ; Ultrasonography

OBJECTIVE: The clinical uses of screws are increasing with broader applications in spinal disorders. When screws are inserted repeatedly to achieve optimal position, tips of screw pitch may become damaged during insertion even though there are significant differences in the moduli of elasticity between bone and titanium. The effect of repeated screw insertion on pullout resistance was investigated. METHODS: Three different titanium screws(cortical lateral mass screw, cancellous lateral mass screw and cervical vertebral body screw) were inserted into the synthetic cancellous material and then extracted axially at a rate of 2.4mm/min using Instron(Model TT-D, Canton, MA). Each set of screws was inserted and pulled out three times. There were six screws in each group. The insertional torque was measured with a torque wrench during insertion. Pullout strength was recorded with a digital oscilloscope. RESULTS: The mean pullout force measurements for the cortical lateral mass screws(185.66N+/-42.60, 167.10N+/-27.01 and 162.52 N+/-23.83 for first, second and third pullout respectively: p=0.03) and the cervical vertebral body screws(386.0N+/-24.1, 360.2N+/-17.5 and 330.9N+/-16.7: p=0.0024) showed consecutive decrease in pullout resistance after each pullout, whereas the cancellous lateral mass screws did not(194.00N+/-36.47, 219.24N+/-26.58 and 199.49N(36.63: p=0.24). The SEM after insertion and pullout three times showed a blunting in the tip of the screw pitch and a smearing of the screw surface. CONCLUSIONS: Repetitive screw insertion and pullout resulted in the decrease of pullout resistance in certain screws possibly caused by blunting the screw tip. This means screw tips suffer deformations during either repeated insertion or pullout. Thus, the screws that have been inserted should not be used for the final construct.
Elasticity ; Titanium ; Torque

Elastography is an imaging modality for the evaluation of tissue stiffness, which has been used for the analysis of superficial organs, such as those of the breast and prostate. The measurement of tissue elasticity has been reported to be useful for the diagnosis and differentiation of tumors, which are stiffer than normal tissues. Endoscopic ultrasonography elastography (EUS-EG) is a promising imaging technique with a high accuracy for the differential diagnosis of solid pancreatic tumors. However, to date EUS-EG has not been used to provide complementary information for biologic behavior of adenxal mass. We report our experience of EUS-EG in a patient with adnexal mass.
Breast ; Diagnosis, Differential ; Elasticity ; Elasticity Imaging Techniques ; Endosonography ; Humans ; Prostate

PURPOSE: This study was conducted to determine the influence of standoff material on acoustic radiation force impulse (ARFI) measurements in an elasticity phantom by using two different probes. METHODS: Using ARFI elastography, 10 observers measured the shear wave velocity (SWV, m/sec) in different lesions of an elasticity phantom with a convex 4C1 probe and a linear 9L4 probe. The experimental setup was expanded by the use of an interposed piece of porcine muscle as standoff material. The probe pressure on the phantom was registered. RESULTS: Faulty ARFI measurements occurred more often when quantifying the hardest lesion (74.0 kPa 4.97 m/sec) by the 9L4 probe with the porcine muscle as a standoff material interposed between the probe and the phantom. The success rate for ARFI measurements in these series was 52.4%, compared with 99.5% in the other series. The SWV values measured with the 9L4 probe were significantly higher (3.33±1.39 m/sec vs. 2.60±0.74 m/sec, P < 0.001 in the group without muscle) and were closer to the reference value than those measured with the 4C1 probe (0.25±0.23 m/sec vs. 0.85±1.21 m/sec, P < 0.001 in the same group). The SWV values measured when using the muscle as a standoff material were lower than those without the muscle (significant for 9L4, P=0.040). The deviation from the reference value and the variance increased significantly with the 9L4 probe if the muscle was in situ (B=0.27, P=0.004 and B=0.32, P < 0.001). In our study, the pressure exerted by the operator had no effect on the SWV values. CONCLUSION: The presence of porcine muscle acting as a standoff material influenced the occurrence of failed measurements as well as the variance and the accuracy of the measured values. The linear high-frequency probe was particularly affected.
Acoustics* ; Elasticity ; Elasticity Imaging Techniques* ; Muscles ; Reference Values ; Transducers ; Ultrasonography

PURPOSE: The purpose of this study was to evaluate how the anisotropy and the static stretch stress of the cervical musculature influence the measured shear modulus in a tissue-mimicking phantom and in cervical lymph nodes in vivo by using shear wave elastography (SWE). METHODS: SWE was performed on a phantom using a pig muscle and on the middle jugular cervical lymph nodes in six volunteers. Tissue elasticity was quantified using the shear modulus and a supersonic shear wave imaging technique. For the phantom study, first, the optimal depth for measurement was determined, and then, SWE was performed in parallel and perpendicular to the muscle fiber orientation with and without strain stress. For the in vivo study, SWE was performed on the cervical lymph nodes in parallel and perpendicular to the sternocleidomastoid muscle fiber direction with and without neck stretching. The mean values of the shear modulus (meanSM) were then analyzed. RESULTS: In the phantom study, the measured depth significantly influenced the meanSM with a sharp decrease at the depth of 1.5 cm (P<0.001). Strain stress increased the meanSM, irrespective of the muscle fiber orientation (P<0.001). In the in vivo study, the meanSM values obtained in parallel to the muscle fiber orientation were greater than those obtained perpendicular to the fiber orientation, irrespective of the stretch stress (P<0.001). However, meanSM was affected significantly by the stretch stress parallel to the muscle fiber orientation (P<0.001). CONCLUSION: The anisotropic nature of the cervical musculature and the applied stretch stress explain the variability of the SWE measurements and should be identified before applying SWE for the interpretation of the measured shear modulus values.
Anisotropy* ; Elasticity ; Elasticity Imaging Techniques* ; Lymph Nodes* ; Neck* ; Ultrasonography* ; Volunteers

The most troublesome of ultrasonic B-mode imaging is the difficulty of accurately diagnosing cancers, benign tumors, and cysts because they appear similar to each other in B-mode images. The human soft tissue has different physical characteristics of ultrasound depending on whether it is normal or not. In particular, cancers in soft tissue tend to be harder than the surrounding tissue. Thus, ultrasound elasticity imaging can be advantageously used to detect cancers. To measure elasticity, a mechanical force is applied to a region of interest, and the degree of deformation measured is rendered as an image. Depending on the method of applying stress and measuring strain, different elasticity imaging modalities have been reported, including strain imaging, sonoelastography, vibro-acoustography, transient elastography, acoustic radiation force impulse imaging, supersonic imaging, and strain-rate imaging. In this paper, we introduce various elasticity imaging methods and explore their technical principles and characteristics.
Elasticity Imaging Techniques ; Elasticity* ; Humans ; Methods ; Ultrasonics ; Ultrasonography*

Burow's graft, obtained from the excised Burow's triangle, is a sort of full-thickness skin graft and can provide outstanding results because the skin used is immediately adjacent to the defects. This procedure is a suitable reconstruction method of surgical defects which are too large for primary closure or within an anatomic subunit with insufficient skin elasticity. Reconstruction of the scalp is not simple owing to lack of elasticity, inflexibility, and hair-bearing feature. We report a case of large sized eccrine poroma on the scalp that was reconstructed with Burow's graft, producing an aesthetically satisfactory result.
Elasticity ; Poroma ; Scalp ; Skin ; Transplants

No abstract available.
Elasticity Imaging Techniques ; Pancreatic Neoplasms

Developing an acoustic radiation force excitation module including 64 channels based in FPGA for ultrasound elastography. The circuit of the module was derived in bipolar, and the parameters such as excitation frequency, pulse repetition frequency, pulse number, element number and focus depth were adjustable. The acoustic field for special parameter was experimented with OptiSon laser acoustic field system with a result which reflects the width of focal spot is about 3 mm. The acoustic power was experimented with RFB2000 radiation force balance with a result which reflects acoustic power is increasing linearly with the number of pulses and the number of elements, and is increasing squarely with the peak-to-peak value of excitation voltage. The module is promising in factual application which can be triggered externally in synchronously, and can be combined with B-mode ultrasound system for ultrasound elastography.
Acoustics ; Elasticity Imaging Techniques ; Ultrasonics