A Quantification System of Needle Visibility in B-mode Ultrasound with Linear and Curved Transducer

International Journal of Biology and Biomedical Engineering ◽

10.46300/91011.2020.14.3 ◽

2020 ◽

Vol 14 ◽

Keyword(s):

Interventional Procedure ◽

Initial Step ◽

Needle Insertion ◽

Specific Reference ◽

Fundamental Physics ◽

Needle Position ◽

Needle Visibility ◽

Visibility Enhancement ◽

Further Development ◽

Insertion Length

Apart from its usefulness in interventional procedure, ultrasound-guided needle insertion has also crucial problem in terms of needle visibility. The inconsistency of needle visibility is needed to be quantified to evaluate the significance of possible technical factors, e.g., imaging strategies, needle type, and needle-transducer relative position. Needle visibility quantification is important as an initial step before further investigation about fundamental physics behind it and further development of needle visibility enhancement. 20G, 150 mm spinal needle inserted in degassed water phantom is imaged with B-mode Flex Focus 800 BK-Medical using 12 MHz linear transducer and 6 MHz curved transducer. The insertion angles are varied between 15°-70°. The quantified visibility representing each needle position are combined into a comprehensive visibility map covering the whole insertion area. It is also evaluated based on insertion length. The results suggest that both linear and curved transducer, for all insertion angles, the distributions of needle visibility have similar pattern and they are not affected by the insertion length. Practically, this applied method of visibility quantification can be used as specific reference and to predict the distribution of needle visibility limited by the specification of needle and ultrasound system, i.e., range of transducer’s frequency and needle’s size.

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Structure and Electrical Properties of an Assembly of Au Nanoclusters

MRS Proceedings ◽

10.1557/proc-635-c1.2 ◽

2001 ◽

Vol 635 ◽

Author(s):

G. Muralidharan ◽

L. Maya ◽

T. Thundat

Keyword(s):

Threshold Voltage ◽

Specific Reference ◽

Low Molecular Weight ◽

Electrical Measurements ◽

Monolayer Films ◽

Au Nanoclusters ◽

Fundamental Physics ◽

Au Clusters ◽

Significant Interest ◽

Potential Applications

AbstractConduction through an assembly of nanosized clusters coupled by tunneling barriers is of significant interest both for understanding the fundamental physics involved and for potential applications. In this study, we describe a technique for preparing relatively large (dimensions of a few 100 µm to a few mm in size) monolayer films consisting of 3 nm diameter Au clusters coated with mercaptododecanoic acid, using low molecular weight-polymers as coupling agents. Electrical measurements of the assembly show non-linear characteristics. Below a certain threshold voltage, the current does not vary with an increase in voltage. Above this threshold voltage, current increases with voltage and can be described by a power-law relationship with an exponent close to unity. These characteristics of the I-V curve are discussed with specific reference to theoretical studies on conduction through an array of capacitance-coupled metallic islands and previous experimental results in similar systems.

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Prospective study of percutaneous tracheostomy: Role of bronchoscopy and surgical technique

SAGE Open Medicine ◽

10.1177/2050312116670407 ◽

2016 ◽

Vol 4 ◽

pp. 205031211667040 ◽

Cited By ~ 2

Author(s):

Tanel Laisaar ◽

Eero Jakobson ◽

Bruno Sarana ◽

Silver Sarapuu ◽

Jüri Vahtramäe ◽

...

Keyword(s):

Intensive Care ◽

Percutaneous Tracheostomy ◽

Surgical Techniques ◽

Needle Insertion ◽

Common Procedure ◽

Unified Protocol ◽

Needle Position ◽

Tissue Dissection ◽

Guide Needle

Objective: Percutaneous tracheostomy is a common procedure but varies considerably in approach. The aim of our study was to evaluate the need for intraoperative bronchoscopy and to compare various surgical techniques. Methods: During 1 year all percutaneous tracheostomies in three intensive care units were prospectively documented according to a unified protocol. In one unit, bronchoscopy was used routinely and in others only during the study. Results: A total of 111 subjects (77 males) with median age 64 (range, 18–86) years and body mass index 25.4 (range, 15.9–50.7) were included. In unit A, tracheal wall was directly exposed; in unit B, limited dissection to enable tracheal palpation was made. In both units, bronchoscopy was used to check the location of an already inserted guiding needle; needle position required correction in 8% and 12% of cases, respectively. In unit C, in tracheostomies without pretracheal tissue dissection, bronchoscopy was used to guide needle insertion; needle position required correction in 66% of cases. Median duration of operations performed by thoracic surgeons and residents was 10 (range, 3–37) min and by intensive care doctors and residents was 16.5 (range, 3–63) min (p < 0.001). Time from the beginning of preparations for tracheostomy until the end of the whole procedure was median 32 min for bedside tracheostomies and 64 min for operations in the operating theatre (p < 0.001). Conclusion: Limited pretracheal tissue dissection enabled proper guiding needle insertion and bronchoscopy was rarely needed. Percutaneous tracheostomies performed by thoracic surgeons took less time, and duration of the whole procedure was remarkably shorter when performed at bedside.

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Insertion Behavior of Microneedles for Drug Delivery

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.47-50.1442 ◽

2008 ◽

Vol 47-50 ◽

pp. 1442-1445

Author(s):

K.T. Shek ◽

David C.C. Lam

Keyword(s):

Drug Delivery ◽

Needle Insertion ◽

Drug Dosage ◽

Porcine Skin ◽

Insertion Depth ◽

Test Frame ◽

Needle Diameter ◽

Gripping Force ◽

Insertion Length ◽

Precision Test

Drug dosage delivered by drug-coated microneedle is dependent on needle insertion behavior. The insertion length and gripping force at varied insertion speeds are determined quantitatively using a precision test frame. The ratio of inserted depth to pressed depth was found to rise asymptotically to a plateau, but decreased rapidly to zero insertion when the needles are pressed less than 1000 microns deep for both silicone rubber and porcine skin. No insertion was observed when the needles are pressed less than 200 microns. The gripping force exerted onto the inserted needle by the skin decreased by 0.1N per mm of needle diameter and insertion depth. The short insertion depth and low force suggest that drug delivery using short 300 micron microneedles would be tenuous. High insertion speeds can help to improve drug delivery, but the improvement is limited to large needles since the results from this study showed that insertions become speedindependent when the needle diameter is less than 130 microns.

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Design and Development of an Augmented Reality Robotic System for Large Tumor Ablation

International Journal of Virtual Reality ◽

10.20870/ijvr.2009.8.1.2710 ◽

2009 ◽

Vol 8 (1) ◽

pp. 27-35 ◽

Cited By ~ 5

Author(s):

Liangjing Yang ◽

Chee-Kong Chui ◽

Stephen Chang

Keyword(s):

Augmented Reality ◽

Interventional Procedure ◽

Needle Insertion ◽

Robotic System ◽

Robot Assisted ◽

Large Tumor ◽

Projection System ◽

Ablation Volume ◽

Insertion Device ◽

Surgical System

An augmented reality based robotic system is proposed for treatment of large liver tumor using multiple overlapping ablations technique. Radiofrequency ablation is a non-resection interventional procedure that minimizes invasiveness and reduces trauma. A single ablation is however limited by the ablation volume coverage. In treatment of tumor with diameter that could be 150mm or more, a single needle insertion will not create sufficient ablation coverage to destroy the entire tumor. As such, multiple insertions are required. The precision and consistency associated with robot assisted surgery coupled with direct augmented reality projection system can better facilitate such treatment. The projection system is equipped with manipulator mechanism and robotic needle insertion arm for multiple insertions and needle deployment. The prototype augmented reality surgical system was evaluated on its abilities in ablating large tumor. Virtual models of the rectangular robot for projector manipulation and robotic needle insertion device were also used to assess the effectiveness of the proposed AR design.

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Endothelial Dysfunction in Dyslipidaemia: Molecular Mechanisms and Clinical Implications

Current Medicinal Chemistry ◽

10.2174/0929867326666190903112146 ◽

2020 ◽

Vol 27 (7) ◽

pp. 1021-1040 ◽

Cited By ~ 5

Author(s):

Bozidarka Zaric ◽

Milan Obradovic ◽

Andreja Trpkovic ◽

Maciej Banach ◽

Dimitri P. Mikhailidis ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Molecular Mechanisms ◽

Lymphatic Vessels ◽

Lipoprotein Metabolism ◽

Initial Step ◽

Beneficial Effects ◽

Relative Contribution ◽

Vessel Remodeling ◽

Vitamin C Supplementation ◽

Further Development

The endothelium consists of a monolayer of Endothelial Cells (ECs) which form the inner cellular lining of veins, arteries, capillaries and lymphatic vessels. ECs interact with the blood and lymph. The endothelium fulfils functions such as vasodilatation, regulation of adhesion, infiltration of leukocytes, inhibition of platelet adhesion, vessel remodeling and lipoprotein metabolism. ECs synthesize and release compounds such as Nitric Oxide (NO), metabolites of arachidonic acid, Reactive Oxygen Species (ROS) and enzymes that degrade the extracellular matrix. Endothelial dysfunction represents a phenotype prone to atherogenesis and may be used as a marker of atherosclerotic risk. Such dysfunction includes impaired synthesis and availability of NO and an imbalance in the relative contribution of endothelialderived relaxing factors and contracting factors such as endothelin-1 and angiotensin. This dysfunction appears before the earliest anatomic evidence of atherosclerosis and could be an important initial step in further development of atherosclerosis. Endothelial dysfunction was historically treated with vitamin C supplementation and L-arginine supplementation. Short term improvement of the expression of adhesion molecule and endothelial function during antioxidant therapy has been observed. Statins are used in the treatment of hyperlipidaemia, a risk factor for cardiovascular disease. Future studies should focus on identifying the mechanisms involved in the beneficial effects of statins on the endothelium. This may help develop drugs specifically aimed at endothelial dysfunction.

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The dyad gene is required for progression through female meiosis in Arabidopsis

Development ◽

10.1242/dev.127.1.197 ◽

2000 ◽

Vol 127 (1) ◽

pp. 197-207 ◽

Cited By ~ 5

Author(s):

I. Siddiqi ◽

G. Ganesh ◽

U. Grossniklaus ◽

V. Subbiah

Keyword(s):

Mother Cell ◽

Megaspore Mother Cell ◽

Female Gametophyte ◽

Molecular Mechanisms ◽

Higher Plants ◽

Embryo Sac ◽

Initial Step ◽

Female Meiosis ◽

Female Germ Cell ◽

Further Development

In higher plants the gametophyte consists of a gamete in association with a small number of haploid cells, specialized for sexual reproduction. The female gametophyte or embryo sac, is contained within the ovule and develops from a single cell, the megaspore which is formed by meiosis of the megaspore mother cell. The dyad mutant of Arabidopsis, described herein, represents a novel class among female sterile mutants in plants. dyad ovules contain two large cells in place of an embryo sac. The two cells represent the products of a single division of the megaspore mother cell followed by an arrest in further development of the megaspore. We addressed the question of whether the division of the megaspore mother cell in the mutant was meiotic or mitotic by examining the expression of two markers that are normally expressed in the megaspore mother cell during meiosis. Our observations indicate that in dyad, the megaspore mother cell enters but fails to complete meiosis, arresting at the end of meiosis 1 in the majority of ovules. This was corroborated by a direct observation of chromosome segregation during division of the megaspore mother cell, showing that the division is a reductional and not an equational one. In a minority of dyad ovules, the megaspore mother cell does not divide. Pollen development and male fertility in the mutant is normal, as is the rest of the ovule that surrounds the female gametophyte. The embryo sac is also shown to have an influence on the nucellus in wild type. The dyad mutation therefore specifically affects a function that is required in the female germ cell precursor for meiosis. The identification and analysis of mutants specifically affecting female meiosis is an initial step in understanding the molecular mechanisms underlying early events in the pathway of female reproductive development.

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Ultrasound Needle Visibility in Contrast Mode Imaging: An In Vitro and Ex Vivo Study

Ultrasound International Open ◽

10.1055/s-0043-101511 ◽

2017 ◽

Vol 03 (02) ◽

pp. E82-E88 ◽

Cited By ~ 1

Author(s):

Marga Rominger ◽

Katharina Martini ◽

Evelyn Dappa ◽

Gilbert Puippe ◽

Volker Klingmüller ◽

...

Keyword(s):

High Resolution ◽

Ex Vivo ◽

Needle Insertion ◽

Biopsy Needle ◽

Linear Probe ◽

Needle Visibility ◽

Acoustic Output ◽

Coded Images ◽

Visible Area

Abstract Purpose To evaluate needle visibility in ultrasound under contrast mode conditions. Materials and Methods Needle visibility was evaluated for bevel, EchoTip® and shaft of 18G Chiba biopsy needle with a 9 MHz linear probe (GE Logiq E9). Insertion angles varied between 30°(steep) and 90°(parallel to the probe surface). The acoustic output varied from 5–28%. 2 different contrast mode presets with either 'Amplitude Modulation' (Penetration) or 'Phase Inversion Harmonics' (High Resolution) were assessed. All other imaging parameters were kept constant. The visibility of bevel, EchoTip® and shaft was assessed for grayscale and color-coded images with a 3-point Likert-like scale (not, poorly, well visible) by 2 independent readers. The echogenicity of the needle bevel, EchoTip® and shaft was assessed in deciBel (dB) on the color-coded images. Results With the parallel insertion angle, all needle areas were well visible. With steep insertion the EchoTip® was the only visible area. High Resolution was superior to Penetration (p<0.001). The visibility and echogenicity of the needle bevel (r grayscale=0.109, pgrayscale=0.178; r color-coded=0.236, pcolor-coded=0.266; r dB=0.956, pdB=0.001), EchoTip® (r grayscale+= 0.477, pgrayscale+= 0.018; r color-coded=0.540, pcolor-coded+= 0.006; r dB=0.911, pdB=0.001) and shaft (r grayscale=0.124, pgrayscale=0.563; r color-coded=0.061, pcolor-coded+= 0.775; r dB+= 0.926, pdB=0.001) increased with increasing acoustic output. Grayscale images were superior to color-coded images for needle visibility (p=0.004). Conclusion Parallel needle insertion, use of an echogenic tip, adequate choice of presets, increased acoustic output, and dual view of grayscale and color-coded images improve needle visibility in ultrasound under contrast mode conditions.

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