Cornea and anterior eye assessment with slit lamp biomicroscopy, specular microscopy, confocal microscopy, and ultrasound biomicroscopy

PubMed Central

Martin, Raul

2018-01-01

Current corneal assessment technologies make the process of corneal evaluation extremely fast and simple, and several devices and technologies show signs that help in identification of different diseases thereby, helping in diagnosis, management, and follow-up of patients. The purpose of this review is to present and update readers on the evaluation of cornea and ocular surface. This first part reviews a description of slit lamp biomicroscopy (SLB), endothelial specular microscopy, confocal microscopy, and ultrasound biomicroscopy examination techniques and the second part describes the corneal topography and tomography, providing up-to-date information on the clinical recommendations of these techniques in eye care practice. Although the SLB is a traditional technique, it is of paramount importance in clinical diagnosis and compulsory when an eye test is conducted in primary or specialist eye care practice. Different techniques allow the early diagnosis of many diseases, especially when clinical signs have not yet become apparent and visible with SLB. These techniques also allow for patient follow-up in several clinical conditions or diseases, facilitating clinical decisions and improving knowledge regarding the corneal anatomy. PMID:29380757

A pilot study of eye-tracking devices in intensive care.

PubMed

Garry, Jonah; Casey, Kelly; Cole, Therese Kling; Regensburg, Angela; McElroy, Colleen; Schneider, Eric; Efron, David; Chi, Albert

2016-03-01

Eye-tracking devices have been suggested as a means of improving communication and psychosocial status among patients in the intensive care unit (ICU). This study was undertaken to explore the psychosocial impact and communication effects of eye-tracking devices in the ICU. A convenience sample of patients in the medical ICU, surgical ICU, and neurosciences critical care unit were enrolled prospectively. Patients participated in 5 guided sessions of 45 minutes each with the eye-tracking computer. After completion of the sessions, the Psychosocial Impact of Assistive Devices Scale (PIADS) was used to evaluate the device from the patient's perspective. All patients who participated in the study were able to communicate basic needs to nursing staff and family. Delirium as assessed by the Confusion Assessment Method for the Intensive Care Unit was present in 4 patients at recruitment and none after training. The device's overall psychosocial impact ranged from neutral (-0.29) to strongly positive (2.76). Compared with the absence of intervention (0 = no change), patients exposed to eye-tracking computers demonstrated a positive mean overall impact score (PIADS = 1.30; P = .004). This finding was present in mean scores for each PIADS domain: competence = 1.26, adaptability = 1.60, and self-esteem = 1.02 (all P < .01). There is a population of patients in the ICU whose psychosocial status, delirium, and communication ability may be enhanced by eye-tracking devices. These 3 outcomes are intertwined with ICU patient outcomes and indirectly suggest that eye-tracking devices might improve outcomes. A more in-depth exploration of the population to be targeted, the device's limitations, and the benefits of eye-tracking devices in the ICU is warranted. Copyright © 2016 Elsevier Inc. All rights reserved.

Feasibility of rotational scan ultrasound imaging by an angled high frequency transducer for the posterior segment of the eye.

PubMed

Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S; Shung, K Kirk

2009-03-01

High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (approximately 1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45 degrees . From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues.

Feasibility of Rotational Scan Ultrasound Imaging by an Angled High Frequency Transducer for the Posterior Segment of the Eye

PubMed Central

Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S.; Shung, K. Kirk

2009-01-01

High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency-dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (∼1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45°. From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues. PMID:19411226

Ultrasound appearances of Implanon implanted contraceptive devices.

PubMed

McNeill, G; Ward, E; Halpenny, D; Snow, A; Torreggiani, W

2009-01-01

Subdermal contraceptive devices represent a popular choice of contraception. Whilst often removed without the use of imaging, circumstances exist where imaging is required. Ultrasound is the modality of choice. The optimal technique and typical sonographic appearances are detailed in this article.

Meta-analysis of Pentacam vs. ultrasound pachymetry in central corneal thickness measurement in normal, post-LASIK or PRK, and keratoconic or keratoconus-suspect eyes.

PubMed

Wu, Wenjing; Wang, Yan; Xu, Lulu

2014-01-01

The aim of this meta-analysis is to evaluate the central corneal thickness (CCT) measurement differences between Pentacam (Oculus Inc., Germany) and Ultrasound Pachymetry (USP) in normal (unoperated eyes , myopic and astigmatic eyes without corneal disease or topographic irregularity), after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), and keratoconic or keratoconus suspected eyes. We assess whether Pentacam and USP have similar CCT differences in normal, thinner corneas after LASIK or PRK procedures, and kerotoconic or keratoconus suspected eyes. Data sources, including PubMed, Medline, EMBASE, and Cochrane Central Registry of Controlled Trials on the Cochrane Library, were searched to find the relevant studies. Primary outcome measures were CCT measurement between Pentacam and USP. Three groups of eyes were analyzed: normal; LASIK or PRK eyes; and keratoconus suspected or keratoconic eyes. Nineteen studies describing 1,908 eyes were enrolled in the normal group. Pentacam results were 1.47 μm ,95 % confidence interval (CI) -2.32 to 5.27, higher than USP without statistically significant difference (P = 0.45). Nine studies with total 539 eyes were included in the corneas after LASIK or PRK. The mean difference in the CCT measurement with Pentacam and ultrasound pachymetry was 1.03 μm, with the 95 % CI -3.36 to 5.42, there was no statistically difference (P = 0.64). Four studies with a total of 185 eyes were included in the keratoconic eyes or keratoconus-suspect group, however,the mean difference was -6.33 μm (95 % CI -9.17 to-3.49), which was statistically different between Pentacam and ultrasound pachymetry in the CCT measurement (P < 0.0001). Pentacam offers similar CCT results to ultrasound pachymetry in normal eyes, thinner corneas after LASIK or PRK procedures. However, in keratoconic or keratoconus-suspect eyes, Pentacam slightly underestimates the central corneal thickness than does ultrasound pachymetry

Large Area MEMS Based Ultrasound Device for Cancer Detection.

PubMed

Wodnicki, Robert; Thomenius, Kai; Hooi, Fong Ming; Sinha, Sumedha P; Carson, Paul L; Lin, Der-Song; Zhuang, Xuefeng; Khuri-Yakub, Pierre; Woychik, Charles

2011-08-21

We present image results obtained using a prototype ultrasound array which demonstrates the fundamental architecture for a large area MEMS based ultrasound device for detection of breast cancer. The prototype array consists of a tiling of capacitive Micro-Machined Ultrasound Transducers (cMUTs) which have been flip-chip attached to a rigid organic substrate. The pitch on the cMUT elements is 185 um and the operating frequency is nominally 9 MHz. The spatial resolution of the new probe is comparable to production PZT probes, however the sensitivity is reduced by conditions that should be correctable. Simulated opposed-view image registration and Speed of Sound volume reconstruction results for ultrasound in the mammographic geometry are also presented.

Large area MEMS based ultrasound device for cancer detection

NASA Astrophysics Data System (ADS)

Wodnicki, Robert; Thomenius, Kai; Ming Hooi, Fong; Sinha, Sumedha P.; Carson, Paul L.; Lin, Der-Song; Zhuang, Xuefeng; Khuri-Yakub, Pierre; Woychik, Charles

2011-08-01

We present image results obtained using a prototype ultrasound array that demonstrates the fundamental architecture for a large area MEMS based ultrasound device for detection of breast cancer. The prototype array consists of a tiling of capacitive Micromachined Ultrasound Transducers (cMUTs) that have been flip-chip attached to a rigid organic substrate. The pitch on the cMUT elements is 185 μm and the operating frequency is nominally 9 MHz. The spatial resolution of the new probe is comparable to those of production PZT probes; however the sensitivity is reduced by conditions that should be correctable. Simulated opposed-view image registration and Speed of Sound volume reconstruction results for ultrasound in the mammographic geometry are also presented.

Handheld ultrasound array imaging device

NASA Astrophysics Data System (ADS)

Hwang, Juin-Jet; Quistgaard, Jens

1999-06-01

A handheld ultrasound imaging device, one that weighs less than five pounds, has been developed for diagnosing trauma in the combat battlefield as well as a variety of commercial mobile diagnostic applications. This handheld device consists of four component ASICs, each is designed using the state of the art microelectronics technologies. These ASICs are integrated with a convex array transducer to allow high quality imaging of soft tissues and blood flow in real time. The device is designed to be battery driven or ac powered with built-in image storage and cineloop playback capability. Design methodologies of a handheld device are fundamentally different to those of a cart-based system. As system architecture, signal and image processing algorithm as well as image control circuit and software in this device is deigned suitably for large-scale integration, the image performance of this device is designed to be adequate to the intent applications. To elongate the battery life, low power design rules and power management circuits are incorporated in the design of each component ASIC. The performance of the prototype device is currently being evaluated for various applications such as a primary image screening tool, fetal imaging in Obstetrics, foreign object detection and wound assessment for emergency care, etc.

Evaluation of a simplified augmented reality device for ultrasound-guided vascular access in a vascular phantom.

PubMed

Jeon, Yunseok; Choi, Seungpyo; Kim, Heechan

2014-09-01

To investigate whether a novel ultrasound device may be used with a simplified augmented reality technique, and to compare this device with conventional techniques during vascular access using a vascular phantom. Prospective, randomized study. Anesthesiology and Pain Medicine departments of a university-affiliated hospital. 20 physicians with no experience with ultrasound-guided techniques. All participants performed the vascular access technique on the vascular phantom model using both a conventional device and the new ultrasound device. Time and the number of redirections of the needle until aspiration of dye into a vessel of the vascular phantom were measured. The median/interquartile range of time was 39.5/41.7 seconds versus 18.6/10.0 seconds (P < 0.001) and number of redirections was 3/3.5 versus 1/0 (P < 0.001) for the conventional and novel ultrasound devices, respectively. During vascular access in a vascular phantom model, the novel device decreased the time and the number of redirections significantly. The device successfully improved the efficiency of the ultrasound-guided vascular access technique. Copyright © 2014 Elsevier Inc. All rights reserved.

[Sonography of the eye and orbit with a multipurpose ultrasound unit].

PubMed

Bergès, O; Koskas, P; Lafitte, F; Piekarski, J-D

2006-04-01

Our goal is to help echographists and radiologists become familiar with the various possibilities indications, technique and results of ophtalmic ultrasonography. We used a multipurpose ultrasound unit. The frequency of the transducer has to be equal or superior to 7.5 MHz. Color Doppler allowing the study of low flows is useful. The study must be standardized: the first step is to obtain measurements of both eyes. Then the entire globe is systematically evaluated. Finally, the orbital structures and vessels of the eye and orbit are analized. After a review of the anatomy and the normal sonographic features, the main indications are described as well as the main pathologies. Special attention is paid to intravitreal hemorrhage, retinal and choroidal detachments, intraocular tumors and orbital space occupying lesions.

Ultrasound-enhanced delivery of antibiotics and anti-inflammatory drugs into the eye.

PubMed

Nabili, Marjan; Patel, Hetal; Mahesh, Sankaranarayana P; Liu, Ji; Geist, Craig; Zderic, Vesna

2013-04-01

Delivery of sufficient amounts of therapeutic drugs into the eye is often a challenging task. In this study, ultrasound application (frequencies of 400 KHz to 1 MHz, intensities of 0.3-1.0 W/cm(2) and exposure duration of 5 min) was investigated to overcome the barrier properties of cornea, which is a typical route for topical administration of ophthalmic drugs. Permeability of ophthalmic drugs, tobramycin and dexamethasone and sodium fluorescein, a drug-mimicking compound, was studied in ultrasound- and sham-treated rabbit corneas in vitro using a standard diffusion cell setup. Light microscopy observations were used to determine ultrasound-induced structural changes in the cornea. For tobramycin, an increase in permeability for ultrasound- and sham-treated corneas was not statistically significant. Increase of 46%-126% and 32%-109% in corneal permeability was observed for sodium fluorescein and dexamethasone, respectively, with statistical significance (p < 0.05) achieved at all treatment parameter combinations (compared with sham treatments) except for 1-MHz ultrasound applications for dexamethasone experiments. This permeability increase was highest at 400 kHz and appeared to be higher at higher intensities applied. Histologic analysis showed structural changes that were limited to epithelial layers of cornea. In summary, ultrasound application provided enhancement of drug delivery, increasing the permeability of the cornea for the anti-inflammatory ocular drug dexamethasone. Future investigations are needed to determine the effectiveness and safety of this application in in vivo long-term survival studies. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Ultrasound-Enhanced Delivery of Antibiotics and Anti-Inflammatory Drugs into the Eye

PubMed Central

Nabili, Marjan; Patel, Hetal; Mahesh, Sankaranarayana P.; Liu, Ji; Geist, Craig; Zderic, Vesna

2013-01-01

Delivery of sufficient amounts of therapeutic drugs into the eye is often a challenging task. In this study, ultrasound application (frequencies of 400 KHz to 1 MHz, intensities of 0.3–1.0 W/cm2 and exposure duration of 5 min) was investigated to overcome the barrier properties of cornea, which is a typical route for topical administration of ophthalmic drugs. Permeability of ophthalmic drugs, tobramycin and dexamethasone and sodium fluorescein, a drug-mimicking compound, was studied in ultrasound- and sham-treated rabbit corneas in vitro using a standard diffusion cell setup. Light microscopy observations were used to determine ultrasound-induced structural changes in the cornea. For tobramycin, an increase in permeability for ultrasound- and sham-treated corneas was not statistically significant. Increase of 46%–126% and 32%–109% in corneal permeability was observed for sodium fluorescein and dexamethasone, respectively, with statistical significance (p < 0.05) achieved at all treatment parameter combinations (compared with sham treatments) except for 1-MHz ultrasound applications for dexamethasone experiments. This permeability increase was highest at 400 kHz and appeared to be higher at higher intensities applied. Histologic analysis showed structural changes that were limited to epithelial layers of cornea. In summary, ultrasound application provided enhancement of drug delivery, increasing the permeability of the cornea for the anti-inflammatory ocular drug dexamethasone. Future investigations are needed to determine the effectiveness and safety of this application in in vivo long-term survival studies. (E-mail: mnabili@gwu.edu) PMID:23415283

Comparison of ultrasound biomicroscopy and ultrasonographic parameters in eyes with phacomorphic glaucoma and eyes with mature cataract.

PubMed

Subbiah, Sujata; Thomas, Philip A; Nelson Jesudasan, C A

2017-08-01

To compare data on anatomical and biometric parameters, and their combination, obtained by using ultrasound biomicroscopy (UBM) and A-scan in eyes with phacomorphic glaucoma (PG) and eyes with mature cataract and to determine differences that may predispose to development of PG. Eighty patients (80 eyes) were enrolled in this cross-sectional study. Anterior chamber parameters, namely anterior chamber depth (ACD), angle-opening distance (AOD), iris-lens contact distance (ILCD), and trabecular-ciliary process distance (TCPD), among other parameters, were assessed by UBM (35 MHz), while axial length (AL) and lenticular thickness (LT) were determined by A-scan biometry. Absolute lenticular position (ALP) and relative lenticular position (RLP) were also compared. The mean AL of eyes with PG was less (P = 0.64) than the mean AL of eyes with mature cataract. The mean ILCD value in eyes with PG (1.30 ± 0.78 mm) was significantly higher (P = 0.0015) than that in eyes with mature cataract (0.86 ± 0.32 mm). The mean AOD value in eyes with PG (0.15 ± 0.10 mm) was significantly lower (P < 0.0001) than that in eyes with mature cataract (0.23 ± 0.06 mm); similarly, the mean RLP value in eyes with PG (0.20 ± 0.02) was significantly lower (P < 0.0001) than that in eyes with mature cataract (0.17 ± 0.02). TCPD showed negative correlation with LT r = -0.514; P = 0.017, r 2  = 0.264, in eyes with phacomorphic glaucoma and mature cataracts showed significant negative correlation of ILCD with AL (r = -0.575; P = 0.025, r 2  = 0.330). The results of UBM examination suggest that there are multiple mechanisms underlying the pathophysiology of PG, namely crowding of the anterior segment, increased iris-lens contact distance, and a more pronounced anterior shift of the lens. Simultaneous evaluation of anatomic and biometric parameters can improve diagnostic accuracy in predicting cases at risk for PG.

Evaluation of the anterior chamber angle in Asian Indian eyes by ultrasound biomicroscopy and gonioscopy.

PubMed

Kaushik, Sushmita; Jain, Rajeev; Pandav, Surinder Singh; Gupta, Amod

2006-09-01

To compare the ultrasound biomicroscopic measurement of the anterior chamber angle in Asian Indian eyes, with the angle width estimated by gonioscopy. Patients with open and closed angles attending a glaucoma clinic were recruited for the study. Temporal quadrants of the angles of patients were categorized by gonioscopy as Grade 0 to Grade 4, using Shaffer's classification. These angles were quantified by ultrasound biomicroscopy (UBM) using the following biometric characteristics: Angle opening distance at 250 micro (AOD 250) and 500 micro (AOD 500) from the scleral spur and trabecular meshwork-ciliary process distance (TCPD). The angles were further segregated as "narrow angles" (Schaffer's Grade 2 or less) and "open angles" (Schaffer's Grade 3 and 4). The UBM measurements were computed in each case and analyzed in relation to the gonioscopic angle evaluation. One hundred and sixty three eyes of 163 patients were analyzed. One hundred and six eyes had "narrow angles" and 57 eyes had "open angles" on gonioscopy. There was a significant difference among the mean UBM measurements of each angle grade estimated by gonioscopy (P < 0.001). The Pearson correlation coefficient between all UBM parameters and gonioscopy grades was significant at the 0.01 level. The mean AOD 250, AOD 500 and TCPD in narrow angles were 58+/-49 micro, 102+/-84 micro and 653+/-124 respectively, while it was 176+/-47 micro, 291+/-62 micro and 883+/-94 micro in eyes with open angles (P < 0.001) respectively. The angle width estimated by gonioscopy correlated significantly with the angle dimensions measured by UBM. Gonioscopy, though a subjective test, is a reliable method for estimation of the angle width.

Algorithms and Results of Eye Tissues Differentiation Based on RF Ultrasound

PubMed Central

Jurkonis, R.; Janušauskas, A.; Marozas, V.; Jegelevičius, D.; Daukantas, S.; Patašius, M.; Paunksnis, A.; Lukoševičius, A.

2012-01-01

Algorithms and software were developed for analysis of B-scan ultrasonic signals acquired from commercial diagnostic ultrasound system. The algorithms process raw ultrasonic signals in backscattered spectrum domain, which is obtained using two time-frequency methods: short-time Fourier and Hilbert-Huang transformations. The signals from selected regions of eye tissues are characterized by parameters: B-scan envelope amplitude, approximated spectral slope, approximated spectral intercept, mean instantaneous frequency, mean instantaneous bandwidth, and parameters of Nakagami distribution characterizing Hilbert-Huang transformation output. The backscattered ultrasound signal parameters characterizing intraocular and orbit tissues were processed by decision tree data mining algorithm. The pilot trial proved that applied methods are able to correctly classify signals from corpus vitreum blood, extraocular muscle, and orbit tissues. In 26 cases of ocular tissues classification, one error occurred, when tissues were classified into classes of corpus vitreum blood, extraocular muscle, and orbit tissue. In this pilot classification parameters of spectral intercept and Nakagami parameter for instantaneous frequencies distribution of the 1st intrinsic mode function were found specific for corpus vitreum blood, orbit and extraocular muscle tissues. We conclude that ultrasound data should be further collected in clinical database to establish background for decision support system for ocular tissue noninvasive differentiation. PMID:22654643

Petroleum Jelly: A Novel Medium for Ocular Ultrasound.

PubMed

Engelbert, Patrick R; Palma, James K

2015-08-01

Ocular ultrasound is a useful emergency department imaging modality for evaluation of many conditions, such as retinal detachment, vitreous detachment, vitreous hemorrhage, and elevated intracranial pressure. Obtaining satisfactory ocular ultrasound images requires the use of a medium that eliminates the air interface between the patient's eye and the transducer. Ultrasound gel is most commonly used; however, the use of a transparent dressing applied to the closed eye prior to the application of gel has also been described as a suitable technique. Ocular ultrasound is performed with the high-frequency linear array transducer using a medium to eliminate the air interface between the eye and the transducer. Although ultrasound gel is most frequently used, it can cause minor eye irritation. Placing a transparent dressing over a closed eye prior to application of gel can eliminate the eye irritation. However, our experience in training >500 students in ocular ultrasound has shown that air is frequently introduced underneath the dressing, which leads to poor-quality images. This article introduces petroleum jelly as a medium for ocular ultrasound. By applying a layer of petroleum jelly over the closed eye and allowing it to warm via body heat for 30 to 45 s, this medium can both minimize patient discomfort and provide easily obtainable, high-quality ocular ultrasound images. This article introduces petroleum jelly as a safe, comfortable, and effective medium for ocular ultrasound examination. Published by Elsevier Inc.

A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

PubMed

Kim, Dohyun; Park, Sung-Ho

2016-11-01

Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

76 FR 43119 - Medical Devices; General and Plastic Surgery Devices; Classification of the Focused Ultrasound...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... and it is identified as a device using focused ultrasound to produce localized, mechanical motion... labeling includes warnings related to patient reaction in terms of pain and information to user in terms of observable skin reactions that are known to be precursors to the potential thermal adverse effects...

Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Patel, N.; Gibson, C.; Alexander, D.;

In-line positioning of ultrasound images using wireless remote display system with tablet computer facilitates ultrasound-guided radial artery catheterization.

PubMed

Tsuchiya, Masahiko; Mizutani, Koh; Funai, Yusuke; Nakamoto, Tatsuo

2016-02-01

Ultrasound-guided procedures may be easier to perform when the operator's eye axis, needle puncture site, and ultrasound image display form a straight line in the puncture direction. However, such methods have not been well tested in clinical settings because that arrangement is often impossible due to limited space in the operating room. We developed a wireless remote display system for ultrasound devices using a tablet computer (iPad Mini), which allows easy display of images at nearly any location chosen by the operator. We hypothesized that the in-line layout of ultrasound images provided by this system would allow for secure and quick catheterization of the radial artery. We enrolled first-year medical interns (n = 20) who had no prior experience with ultrasound-guided radial artery catheterization to perform that using a short-axis out-of-plane approach with two different methods. With the conventional method, only the ultrasound machine placed at the side of the head of the patient across the targeted forearm was utilized. With the tablet method, the ultrasound images were displayed on an iPad Mini positioned on the arm in alignment with the operator's eye axis and needle puncture direction. The success rate and time required for catheterization were compared between the two methods. Success rate was significantly higher (100 vs. 70 %, P = 0.02) and catheterization time significantly shorter (28.5 ± 7.5 vs. 68.2 ± 14.3 s, P < 0.001) with the tablet method as compared to the conventional method. An ergonomic straight arrangement of the image display is crucial for successful and quick completion of ultrasound-guided arterial catheterization. The present remote display system is a practical method for providing such an arrangement.

Qualitative Assessment of Ultrasound Biomicroscopic Images Using Standard Photographs: The Liwan Eye Study

PubMed Central

Jiang, Yuzhen; Huang, Wenyong; Huang, Qunxiao; Zhang, Jian; Foster, Paul J.

2010-01-01

Objective. To classify anatomic features related to anterior chamber angles by a qualitative assessment system based on ultrasound biomicroscopy (UBM) images. Methods. Cases of primary angle-closure suspect (PACS), defined by pigmented trabecular meshwork that is not visible in two or more quadrants on static gonioscopy (cases) and systematically selected subjects (1 of every 10) who did not meet this criterion (controls) were enrolled during a population-based survey in Guangzhou, China. All subjects underwent UBM examination. A set of standard UBM images was used to qualitatively classify anatomic features related to the angle configuration, including iris thickness, iris convexity, iris angulation, ciliary body size, and ciliary process position. All analysis was conducted on right eye images. Results. Based on the qualitative grades, the difference in overall iris thickness between gonioscopically narrow eyes (n = 117) and control eyes (n = 57) was not statistically significant. The peripheral one third of the iris tended to be thicker in all quadrants of the PACS eyes, although the difference was statistically significant only in the superior quadrant (P = 0.008). No significant differences were found in the qualitative classifications of iris insertion, iris angulation, ciliary body size, and ciliary process position. The findings were similar when compared with the control group of eyes with wide angles in all quadrants. Conclusions. Basal iris thickness seems to be more relevant to narrow angle configuration than to overall iris thickness. Otherwise, the anterior rotation and size of the ciliary body, the iris insertion, and the overall iris thickness are comparable in narrow- and wide-angle eyes. PMID:19834039

[Application of ultrasound-enhanced gene and drug delivery to the ocular tissue].

PubMed

Sonoda, Shozo; Yamashita, Toshifumi; Suzuki, Ryo; Maruyama, Kazuo; Sakamoto, Taiji

2013-01-01

Visual images provide an immensely rich source of information about the external world. Eye has characteristic structure sensory cells are arranged along the eye wall, and is filled inside with vitreous body. In recent years, intravitreal injection of anti-vascular endothelial growth factor (VEGF) agent had widely spread, and numerous number of patients who suffered ocular angiogenic disease such as diabetic retinopathy, age-related macular degeneration and retinal vascular occlusion for the disease, were treated and spared the blindness. Vitreous cavity was regarded as reservoir of drug, intravitreal injection is thought a sort of drug delivery. However, with regard to the administration of a selective drug deliver, it has not yet been solved. Our aim is to establish a new method of gene transfer, drug delivery using low-energy ultrasound to the eye, to date, we confirmed drug and gene deliver to the ocular tissue such as cornea, conjunctiva and retina with high efficiency. In addition, tissue damage was minimal. We have also shown that ultrasound irradiation with combination of a microbubbles or bubble liposome could be introduced drug and gene more effectively. Based on these knowledge, we will focus on development of a new device for intraocular ultrasound exposure and potential for therapeutic application of ultrasound to humans retinal disease such as retinal artery obstruction.

MR compatible positioning device for guiding a focused ultrasound system for the treatment of brain deseases.

PubMed

Mylonas, N; Damianou, C

2014-03-01

A prototype magnetic resonance imaging (MRI)-compatible positioning device that navigates a high intensity focused ultrasound (HIFU) transducer is presented. The positioning device has three user-controlled degrees of freedom that allow access to brain targets using a lateral coupling approach. The positioning device can be used for the treatment of brain cancer (thermal mode ultrasound) or ischemic stroke (mechanical mode ultrasound). The positioning device incorporates only MRI compatible materials such as piezoelectric motors, ABS plastic, brass screws, and brass rack and pinion. The robot has the ability to accurately move the transducer thus creating overlapping lesions in rabbit brain in vivo. The registration and repeatability of the system was evaluated using tissues in vitro and gel phantom and was also tested in vivo in the brain of a rabbit. A simple, cost effective, portable positioning device has been developed which can be used in virtually any clinical MRI scanner since it can be placed on the table of the MRI scanner. This system can be used to treat in the future patients with brain cancer and ischemic stroke. Copyright © 2013 John Wiley & Sons, Ltd.

Measurement of central corneal thickness with optical low-coherence reflectometry and ultrasound pachymetry in normal and post-femtosecond laser in situ keratomileusis eyes.

PubMed

Huang, Jinhai; Liao, Na; Savini, Giacomo; Li, Yuanguang; Bao, Fangjun; Yu, Ye; Yu, Ayong; Wang, Qinmei

2015-02-01

To determine the repeatability and reproducibility of measurements of central corneal thickness (CCT) using optical low-coherence reflectometry (Lenstar LS900; Haag Streit) in normal eyes and post-femtosecond laser in situ keratomileusis (post-FS-LASIK) eyes and evaluate their agreement with ultrasound (US) pachymetry. CCT was measured using Lenstar and US pachymetry sequentially in normal and post-FS-LASIK eyes by 2 experienced observers. Intraoperator repeatability and interoperator reproducibility were assessed by within-subject standard deviation, test-retest repeatability, coefficient of variation (CoV), and intraclass correlation coefficient. Paired t-tests and Bland-Altman plots were used for analyzing agreement between the 2 devices. In this study, 55 healthy subjects and 50 post-FS-LASIK patients were recruited. Test-retest repeatability of Lenstar was within 10 μm, CoV was less than 1.0%, and intraclass correlation coefficient was more than 0.9 in both normal and post-FS-LASIK groups. Mean difference between these methods was 1.4 ± 4.2 μm and -1.7 ± 5.4 μm, respectively. Moreover, measurements of CCT showed narrow 95% limits of agreement (range, normal group: -6.8 and 9.6 μm; post-FS-LASIK group: -12.4 and 8.9 μm), which implied good agreement. Measurements of CCT using Lenstar showed excellent intraoperator repeatability and interoperator reproducibility both in normal eyes and post-FS-LASIK eyes. Measurements of CCT using Lenstar and US pachymetry showed good agreement and both can be used interchangeably.

Efficiency of quantitative echogenicity for investigating supraspinatus tendinopathy by the gray-level histogram of two ultrasound devices.

PubMed

Hsu, Jiun-Cheng; Chen, Po-Han; Huang, Kuo-Chin; Tsai, Yao-Hung; Hsu, Wei-Hsiu

2017-10-01

The gray-level histogram of ultrasound is a promising tool for scanning the hypoechogenic appearance of supraspinatus tendinopathy, and the aim of this study was to test the hypothesis that the gray-level value of the supraspinatus tendon in the painful shoulder has a lower value on B-mode images even though in different ultrasound devices. Sixty-seven patients who had unilateral shoulder pain with rotator cuff tendinopathy underwent bilateral shoulder ultrasonography, and we compared the mean gray-level values of painful shoulders and contralateral shoulders without any pain in each patient using two ultrasound devices. The echogenicity ratio (symptomatic/asymptomatic side) of two ultrasound devices was compared. A significant difference existed between the symptomatic shoulder and contralateral asymptomatic shoulder (p < 0.001) on the mean gray-level value measurements of each device. The symptomatic-to-asymptomatic tendon echogenicity ratio of device A was 0.919 ± 0.090 in the transverse plane and 0.937 ± 0.081 in the longitudinal plane, and the echogenicity ratio of device B was 0.899 ± 0.113 in the transverse plane and 0.940 ± 0.113 in the longitudinal plane. The decline of the mean gray-level value and the echogenicity ratio of the supraspinatus tendon in the painful shoulder may be utilized as a useful sonographic reference of unilateral rotator cuff lesions. Diagnostic level III.

Targeted Prostate Thermal Therapy with Catheter-Based Ultrasound Devices and MR Thermal Monitoring

NASA Astrophysics Data System (ADS)

Diederich, Chris; Ross, Anthony; Kinsey, Adam; Nau, Will H.; Rieke, Viola; Butts Pauly, Kim; Sommer, Graham

2006-05-01

Catheter-based ultrasound devices have significant advantages for thermal therapy procedures, including potential for precise spatial and dynamic control of heating patterns to conform to targeted volumes. Interstitial and transurethral ultrasound applicators, with associated treatment strategies, were developed for thermal ablation of prostate combined with MR thermal monitoring. Four types of multielement transurethral applicators were devised, each with different levels of selectivity and intended therapeutic goals: sectored tubular transducer devices with fixed directional heating patterns; planar and lightly focused curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Similarly, interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with fixed directional heating patterns (e.g., 180 deg.). In vivo experiments in canine prostate (n=15) under MR temperature imaging were used to evaluate the heating technology and develop treatment strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature contours and thermal dose in multiple slices through the target volume. Sectored transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. The curvilinear applicator produces distinct 2-3 mm wide lesions, and with sequential rotation and modulated dwell time can precisely conform thermal ablation to selected areas or the entire prostate gland. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with

The eye-tracking computer device for communication in amyotrophic lateral sclerosis.

PubMed

Spataro, R; Ciriacono, M; Manno, C; La Bella, V

2014-07-01

To explore the effectiveness of communication and the variables affecting the eye-tracking computer system (ETCS) utilization in patients with late-stage amyotrophic lateral sclerosis (ALS). We performed a telephone survey on 30 patients with advanced non-demented ALS that were provisioned an ECTS device. Median age at interview was 55 years (IQR = 48-62), with a relatively high education (13 years, IQR = 8-13). A one-off interview was made and answers were later provided with the help of the caregiver. The interview included items about demographic and clinical variables affecting the daily ETCS utilization. The median time of ETCS device possession was 15 months (IQR = 9-20). The actual daily utilization was 300 min (IQR = 100-720), mainly for the communication with relatives/caregiver, internet surfing, e-mailing, and social networking. 23.3% of patients with ALS (n = 7) had a low daily ETCS utilization; most reported causes were eye-gaze tiredness and oculomotor dysfunction. Eye-tracking computer system is a valuable device for AAC in patients with ALS, and it can be operated with a good performance. The development of oculomotor impairment may limit its functional use. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preliminary Experience Using Eye-Tracking Technology to Differentiate Novice and Expert Image Interpretation for Ultrasound-Guided Regional Anesthesia.

PubMed

Borg, Lindsay K; Harrison, T Kyle; Kou, Alex; Mariano, Edward R; Udani, Ankeet D; Kim, T Edward; Shum, Cynthia; Howard, Steven K

2018-02-01

Objective measures are needed to guide the novice's pathway to expertise. Within and outside medicine, eye tracking has been used for both training and assessment. We designed this study to test the hypothesis that eye tracking may differentiate novices from experts in static image interpretation for ultrasound (US)-guided regional anesthesia. We recruited novice anesthesiology residents and regional anesthesiology experts. Participants wore eye-tracking glasses, were shown 5 sonograms of US-guided regional anesthesia, and were asked a series of anatomy-based questions related to each image while their eye movements were recorded. The answer to each question was a location on the sonogram, defined as the area of interest (AOI). The primary outcome was the total gaze time in the AOI (seconds). Secondary outcomes were the total gaze time outside the AOI (seconds), total time to answer (seconds), and time to first fixation on the AOI (seconds). Five novices and 5 experts completed the study. Although the gaze time (mean ± SD) in the AOI was not different between groups (7 ± 4 seconds for novices and 7 ± 3 seconds for experts; P = .150), the gaze time outside the AOI was greater for novices (75 ± 18 versus 44 ± 4 seconds for experts; P = .005). The total time to answer and total time to first fixation in the AOI were both shorter for experts. Experts in US-guided regional anesthesia take less time to identify sonoanatomy and spend less unfocused time away from a target compared to novices. Eye tracking is a potentially useful tool to differentiate novices from experts in the domain of US image interpretation. © 2017 by the American Institute of Ultrasound in Medicine.

Noninvasive Dry Eye Assessment Using High-Technology Ophthalmic Examination Devices.

PubMed

Yamaguchi, Masahiko; Sakane, Yuri; Kamao, Tomoyuki; Zheng, Xiaodong; Goto, Tomoko; Shiraishi, Atsushi; Ohashi, Yuichi

2016-11-01

Recently, the number of dry eye cases has dramatically increased. Thus, it is important that easy screening, exact diagnoses, and suitable treatments be available. We developed 3 original and noninvasive assessments for this disorder. First, a DR-1 dry eye monitor was used to determine the tear meniscus height quantitatively by capturing a tear meniscus digital image that was analyzed by Meniscus Processor software. The DR-1 meniscus height value significantly correlated with the fluorescein meniscus height (r = 0.06, Bland-Altman analysis). At a cutoff value of 0.22 mm, sensitivity of the dry eye diagnosis was 84.1% with 90.9% specificity. Second, the Tear Stability Analysis System was used to quantitatively measure tear film stability using a topographic modeling system corneal shape analysis device. Tear film stability was objectively and quantitatively evaluated every second during sustained eye openings. The Tear Stability Analysis System is currently installed in an RT-7000 autorefractometer and topographer to automate the diagnosis of dry eye. Third, the Ocular Surface Thermographer uses ophthalmic thermography for diagnosis. The decrease in ocular surface temperature in dry eyes was significantly greater than that in normal eyes (P < 0.001) at 10 seconds after eye opening. Decreased corneal temperature correlated significantly with the tear film breakup time (r = 0.572; P < 0.001). When changes in the ocular surface temperature of the cornea were used as indicators for dry eye, sensitivity was 0.83 and specificity was 0.80 after 10 seconds. This article describes the details and potential of these 3 noninvasive dry eye assessment systems.

Towards understanding addiction factors of mobile devices: An eye tracking study on effect of screen size.

PubMed

Wibirama, Sunu; Nugroho, Hanung A

2017-07-01

Mobile devices addiction has been an important research topic in cognitive science, mental health, and human-machine interaction. Previous works observed mobile device addiction by logging mobile devices activity. Although immersion has been linked as a significant predictor of video game addiction, investigation on addiction factors of mobile device with behavioral measurement has never been done before. In this research, we demonstrated the usage of eye tracking to observe effect of screen size on experience of immersion. We compared subjective judgment with eye movements analysis. Non-parametric analysis on immersion score shows that screen size affects experience of immersion (p<;0.05). Furthermore, our experimental results suggest that fixational eye movements may be used as an indicator for future investigation of mobile devices addiction. Our experimental results are also useful to develop a guideline as well as intervention strategy to deal with smartphone addiction.

Effect of incisional friction and ophthalmic viscosurgical devices on the heat generation of ultrasound during cataract surgery.

PubMed

Floyd, Michael; Valentine, Jeremy; Coombs, Jamie; Olson, Randall J

2006-07-01

To determine the thermal features of the Legacy (Alcon) and Sovereign (Advanced Medical Optics) phacoemulsification machines in a cadaver eye and with 7 ophthalmic viscosurgical devices (OVDs). In situ and in vitro study. Temperature without occlusion was recorded at the sleeve placed in the wound of a cadaver eye, and temperature over baseline was determined after 60 seconds. The result was then compared with the results in a previous study that used balanced salt solution (BSS) in artificial chambers. In the second portion of the experiment, with irrigation and aspiration lines occluded, temperature was recorded at the sleeve placed in an artificial chamber filled with sodium hyaluronate 2.3% (Healon5), sodium hyaluronate 1.4% (Healon GV), sodium hyaluronate 1.0% (Healon), sodium hyaluronate 1.6% (Amvisc Plus), sodium hyaluronate 1.0% (Provisc), sodium hyaluronate 3.0%-chondroitin sulfate 4.0% (Viscoat), or hyaluronate 3.0% (Vitrax). Temperature over baseline was also determined after 60 seconds. These results were compared with each set of OVD data and with the results in the prior BSS study. In the eye-bank model, the Legacy machine had a 62% temperature increase from incisional friction and the Sovereign machine had a decrease of 8.6% over results in an artificial anterior chamber. The OVD temperature increases were greater for the Sovereign (P<.001) and followed the same general trend for the Legacy. The least temperature increase was with Amvisc Plus, Healon, and Healon GV; the intermediate increases were with Provisc and Vitrax; and the greatest increases were with Viscoat and Healon5. The OVD findings did not correlate with viscosity or pseudoplasticity. Incisional friction alone increased heat generation in the Legacy, a stroke-length driven instrument, more than in the Sovereign, a power-driven instrument. Ophthalmic viscosurgical devices are not only a concern due to outflow occlusion but can also add up to 6 times the heat in comparison with BSS. The

Dual-modality imaging with a ultrasound-gamma device for oncology

NASA Astrophysics Data System (ADS)

Polito, C.; Pellegrini, R.; Cinti, M. N.; De Vincentis, G.; Lo Meo, S.; Fabbri, A.; Bennati, P.; Cencelli, V. Orsolini; Pani, R.

2018-06-01

Recently, dual-modality systems have been developed, aimed to correlate anatomical and functional information, improving disease localization and helping oncological or surgical treatments. Moreover, due to the growing interest in handheld detectors for preclinical trials or small animal imaging, in this work a new dual modality integrated device, based on a Ultrasounds probe and a small Field of View Single Photon Emission gamma camera, is proposed.

High-intensity focused ultrasound treatment in refractory glaucoma patients: results at 1 year of prospective clinical study.

PubMed

Melamed, Shlomo; Goldenfeld, Modi; Cotlear, Daniel; Skaat, Alon; Moroz, Iris

2015-01-01

To evaluate the safety and efficacy of the ultrasonic circular cyclo-coagulation procedure using high-intensity focused ultrasound by a miniaturized annular device containing 6 piezoceramic transducers in patients with refractory glaucoma. This was a prospective interventional noncomparative study of 20 eyes of 20 patients with refractory glaucoma. All eyes were treated with 6 activated transducers operating at 21 MHz. Ultrasound biomicroscopy and a complete ophthalmic examination were performed before the procedure and at 1 day, 1 week, and 1, 3, 6, and 12 months after the procedure. Primary outcomes were surgical success (defined as intraocular pressure (IOP) reduction from baseline ≥20% and IOP >5 mm Hg) at the last follow-up visit. Secondary outcomes were mean IOP at each follow-up visit compared to baseline, medication use, complications, and re-interventions. Intraocular pressure was significantly reduced (p<0.01) from a mean preoperative value of 36.4 ± 5.7 mm Hg to a mean postoperative value of 22.5 ± 10.3 mm Hg at 12 months. Four patients needed to be re-treated. The mean IOP reduction achieved was 38%. Surgical success was achieved in 13 of 20 eyes (65%). No major intraoperative or postoperative complications occurred. Ultrasonic circular cyclo-coagulation using high-intensity focused ultrasound delivered by a circular miniaturized device containing 6 piezoceramic transducers is an effective and well-tolerated method to reduce IOP in patients with refractory glaucoma.

Exploration Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Young, M.; Mason, S.; Schaefer, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Coble, C.; Gruschkus, S.; Law, J.; Alexander, D.;

Comparison of an imaging heel quantitative ultrasound device (DTU-one) with densitometric and ultrasonic measurements.

PubMed

Diessel, E; Fuerst, T; Njeh, C F; Hans, D; Cheng, S; Genant, H K

2000-01-01

The purpose of this study was to evaluate a new imaging ultrasound scanner for the heel, the DTU-one (Osteometer MediTech, Denmark), by comparing quantitative ultrasound (QUS) results with bone mineral density (BMD) of the heel and femur from dual X-ray absorptiometry (DXA), and by comparing the DTU-one with another QUS device, the UBA 575+. The regions of interest in the DXA heel scan were matched with the regions evaluated by the two QUS devices. 134 healthy and 16 osteoporotic women aged 30-84 years old were enrolled in the study. In vivo short-term precision of the DTU-one for broadband ultrasound attenuation (BUA) and speed of sound (SOS) was 2.9% and 0.1%, respectively, and long-term precision was 3.8% and 0.2%, respectively. Highest correlations (r) between QUS and BMD measurements were achieved when comparing DTU-one results with BMD in matched regions of the DXA heel scan. Correlation coefficients (r) were 0.81 for BUA and SOS. Highest correlations with the UBA 575+ were 0.68 and 0.72, respectively. The comparison of BMD in different femoral sites with BUA and SOS (DTU-one) varied from 0.62 to 0.69 when including the entire study population. The correlation between BMD values within different sites of the femur tended to be higher (from r = 0.81 to 0.93). When comparing BUA with BUA and SOS with SOS on the two QUS devices, the absolute QUS values differed significantly. However, correlations were relatively high, with 0.76 for BUA and 0.82 for SOS. In conclusion, the results of the new quantitative ultrasound device, the DTU-one, are highly correlated (r = 0.8) with results obtained using the UBA 575+ and with BMD in the heel. The precision of the DTU-one is comparable to other QUS devices for BUA and is high for SOS.

Italian chapter of the International Society of cardiovascular ultrasound expert consensus document on training requirements for noncardiologists using hand-carried ultrasound devices.

PubMed

Pelliccia, Francesco; Palmiero, Pasquale; Maiello, Maria; Losi, Maria-Angela

2012-07-01

Hand-carried ultrasound devices (HCDs), also named personal use echo, are pocket-size, compact, and battery-equipped echocardiographic systems. They have limited technical capabilities but offer some advantages compared with standard echocardiographic devices due to their simplicity of use, immediate availability at the patient's bedside, transportability, and relatively low cost. Current HCDs are considered as screening tools and are used to complement the physical examination by cardiologists. Many noncardiologic subspecialists, however, have adopted this technologic advancement rapidly raising the concern of an inappropriate use of HCD by health professionals who do not have any specific training. In keeping with the mission of the International Society of Cardiovascular Ultrasound to advance the science and art of cardiovascular ultrasound and encourage the knowledge of this subject, the purpose of this Expert Consensus document is to focus on the training for all health care professionals considering the use of HCD. Accordingly, this paper summarizes general aspects of HCD, such as technical characteristics and clinical indications, and then details the specific training requirements for noncardiologists (i.e., training program, minimum case load, duration, and certification of competence). © 2012, Wiley Periodicals, Inc.

Glaucoma in modified osteo-odonto-keratoprosthesis eyes: role of additional stage 1A and Ahmed glaucoma drainage device-technique and timing.

PubMed

Iyer, Geetha; Srinivasan, Bhaskar; Agarwal, Shweta; Shetty, Roshni; Krishnamoorthy, Sripriya; Balekudaru, Shantha; Vijaya, Lingam

2015-03-01

To report the technique, timing, and outcomes of the Ahmed glaucoma drainage device in eyes with the modified osteo-odonto-keratoprosthesis (MOOKP) and the role of an additional stage 1A to the Rome-Vienna protocol. Retrospective interventional case series. Case records of 22 eyes of 20 patients with high intraocular pressure at various stages of the MOOKP procedure performed in 85 eyes of 82 patients were studied. Stage 1A, which includes total iridodialysis, intracapsular cataract extraction, and anterior vitrectomy, was done in all eyes as the primary stage. Seventeen Ahmed glaucoma drainage devices were implanted in 15 eyes of 14 patients (chemical injury in 9 [10 eyes] and Stevens-Johnson syndrome in 5 patients). Implantation was performed during and after stage 1A in 2 and 7 eyes, respectively, after stage 1B+1C in 1 eye, and after stage 2 in 6 eyes. Eleven of 15 eyes (73.3%) remained stable with adequate control of intraocular pressure over a mean follow-up period of 33.68 months (1-90 months). Complications related to the drainage device were hypotony in 1 eye and vitreous block of the tube in 1 eye. It is ideal to place the Ahmed glaucoma drainage device prior to the mucosal graft when the anatomy of the ocular surface is least altered with best outcomes. The technique of placement of the drainage device during the various stages of the MOOKP procedure has been described. The intraocular pressure stabilized in three quarters of the eyes with pre-existing glaucoma. Copyright © 2015 Elsevier Inc. All rights reserved.

2D array transducers for real-time 3D ultrasound guidance of interventional devices

NASA Astrophysics Data System (ADS)

Light, Edward D.; Smith, Stephen W.

2009-02-01

We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

Medical applications of near-eye display devices: an exploratory study.

PubMed

Vorraber, Wolfgang; Voessner, Siegfried; Stark, Gerhard; Neubacher, Dietmar; DeMello, Steven; Bair, Aaron

2014-12-01

Near-eye display devices (such as Google Glass) may improve the efficiency and effectiveness of clinical care by giving clinicians information (such as the patient's vital signs) continuously within their field of vision during various procedures. We describe the use of Glass during a radiological intervention in three patients. Other possible applications (including tele-mentoring and the supervision of trainees) are discussed and a classification proposed. An app was developed to facilitate the use of Glass, so vital physical signs (pulse and blood pressure) could be projected on the near-eye display, via an intranet to protect sensitive data. The device was then used during radiological interventions (percutaneous transluminal angioplasty) in three patients, and assessed by the interventionalists who were interviewed before and after each procedure. The interventionalists reported that Google Glass improved concentration on the task in hand by reducing head and neck movements (which would be needed to view several remote monitors). However, heat generation by the device and low battery capacity are shortcomings for which solutions must be developed, and data protection is mandatory. Google Glass may have a number of clinical applications and can quicken interventions where vital signs or other visual data need to be monitored by the operator. Copyright © 2014 Surgical Associates Ltd. All rights reserved.

A 100-200 MHz ultrasound biomicroscope.

PubMed

Knspik, D A; Starkoski, B; Pavlin, C J; Foster, F S

2000-01-01

The development of higher frequency ultrasound imaging systems affords a unique opportunity to visualize living tissue at the microscopic level. This work was undertaken to assess the potential of ultrasound imaging in vivo using the 100-200 MHz range. Spherically focused lithium niobate transducers were fabricated. The properties of a 200 MHz center frequency device are described in detail. This transducer showed good sensitivity with an insertion loss of 18 dB at 200 MHz. Resolution of 14 /spl mu/m in the lateral direction and 12 /spl mu/m in the axial direction was achieved with f/1.14 focusing. A linear mechanical scan system and a scan converter were used to generate B-scan images at a frame rate up to 12 frames per second. System performance in B-mode imaging is limited by frequency dependent attenuation in tissues. An alternative technique, zone-focus image collection, was investigated to extend depth of field. Images of coronary arteries, the eye, and skin are presented along with some preliminary correlations with histology. These results demonstrate the feasibility of ultrasound biomicroscopy In the 100-200 MHz range. Further development of ultrasound backscatter imaging at frequencies up to and above 200 MHz will contribute valuable information about tissue microstructure.

Design of integrated eye tracker-display device for head mounted systems

NASA Astrophysics Data System (ADS)

David, Y.; Apter, B.; Thirer, N.; Baal-Zedaka, I.; Efron, U.

2009-08-01

We propose an Eye Tracker/Display system, based on a novel, dual function device termed ETD, which allows sharing the optical paths of the Eye tracker and the display and on-chip processing. The proposed ETD design is based on a CMOS chip combining a Liquid-Crystal-on-Silicon (LCoS) micro-display technology with near infrared (NIR) Active Pixel Sensor imager. The ET operation allows capturing the Near IR (NIR) light, back-reflected from the eye's retina. The retinal image is then used for the detection of the current direction of eye's gaze. The design of the eye tracking imager is based on the "deep p-well" pixel technology, providing low crosstalk while shielding the active pixel circuitry, which serves the imaging and the display drivers, from the photo charges generated in the substrate. The use of the ETD in the HMD Design enables a very compact design suitable for Smart Goggle applications. A preliminary optical, electronic and digital design of the goggle and its associated ETD chip and digital control, are presented.

Ultrasound biomicroscopic findings in hallerman-streiff syndrome.

PubMed

Sato, Miho; Terasaki, Hiroko; Amano, Emil; Okamoto, Yoko; Miyake, Yozo

2002-01-01

To demonstrate the usefulness of ultrasound biomicroscopy in detecting the morphological changes in the lens caused by the spontaneous absorption of lens material and to detect fundus abnormalities in a patient with Hallermann-Streiff syndrome. Case report of an infant diagnosed at the age of 2 months as having Hallermann-Streiff syndrome. Spontaneous lens absorption occurred during the course of follow-up and was detected only by ultrasound biomicroscopy after the patient was prepared for cataract surgery. The changes in the anterior chamber depth and lens shapes were documented by ultrasound biomicroscopy. Retinal folds that were barely observable by conventional ophthalmoscopy because of a dense cataract were clearly shown by ultrasound biomicroscopy. Ultrasound biomicroscopy can be used to examine the lenses of eyes that are not observable with conventional optical instruments. Ultrasound biomicroscopy can also be used to study the posterior segment of microphthalmic eyes. We recommend preoperative ultrasound biomicroscopy to prevent unnecessary anesthesia and surgical preparation.

Clinical ophthalmic ultrasound improvements

NASA Technical Reports Server (NTRS)

Garrison, J. B.; Piro, P. A.

1981-01-01

The use of digital synthetic aperture techniques to obtain high resolution ultrasound images of eye and orbit was proposed. The parameters of the switched array configuration to reduce data collection time to a few milliseconds to avoid eye motion problems in the eye itself were established. An assessment of the effects of eye motion on the performance of the system was obtained. The principles of synthetic techniques are discussed. Likely applications are considered.

Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

PubMed

Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

2012-01-01

Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. © 2012 IEEE

Prediction of accommodative optical response in prepresbyopic patients using ultrasound biomicroscopy

PubMed Central

Ramasubramanian, Viswanathan; Glasser, Adrian

2015-01-01

PURPOSE To determine whether relatively low-resolution ultrasound biomicroscopy (UBM) can predict the accommodative optical response in prepresbyopic eyes as well as in a previous study of young phakic subjects, despite lower accommodative amplitudes. SETTING College of Optometry, University of Houston, Houston, USA. DESIGN Observational cross-sectional study. METHODS Static accommodative optical response was measured with infrared photorefraction and an autorefractor (WR-5100K) in subjects aged 36 to 46 years. A 35 MHz UBM device (Vumax, Sonomed Escalon) was used to image the left eye, while the right eye viewed accommodative stimuli. Custom-developed Matlab image-analysis software was used to perform automated analysis of UBM images to measure the ocular biometry parameters. The accommodative optical response was predicted from biometry parameters using linear regression, 95% confidence intervals (CIs), and 95% prediction intervals. RESULTS The study evaluated 25 subjects. Per-diopter (D) accommodative changes in anterior chamber depth (ACD), lens thickness, anterior and posterior lens radii of curvature, and anterior segment length were similar to previous values from young subjects. The standard deviations (SDs) of accommodative optical response predicted from linear regressions for UBM-measured biometry parameters were ACD, 0.15 D; lens thickness, 0.25 D; anterior lens radii of curvature, 0.09 D; posterior lens radii of curvature, 0.37 D; and anterior segment length, 0.42 D. CONCLUSIONS Ultrasound biomicroscopy parameters can, on average, predict accommodative optical response with SDs of less than 0.55 D using linear regressions and 95% CIs. Ultrasound biomicroscopy can be used to visualize and quantify accommodative biometric changes and predict accommodative optical response in prepresbyopic eyes. PMID:26049831

An ex vivo rat eye model to aid development of high-resolution retina imaging devices for rodents

NASA Astrophysics Data System (ADS)

van Oterendorp, Christian; Martin, Keith R.; Zhong, Jiang Jian; Diaz-Santana, Luis

2010-09-01

High resolution in vivo retinal imaging in rodents is becoming increasingly important in eye research. Development of suitable imaging devices currently requires many lengthy animal procedures. We present an ex vivo rat model eye with fluorescently labelled retinal ganglion cells (RGC) and nerve fibre bundles that reduces the need for animal procedures while preserving key properties of the living rat eye. Optical aberrations and scattering of four model eyes and eight live rat eyes were quantified using a Shack-Hartmann sensor. Fluorescent images from RGCs were obtained using a prototype scanning laser ophthalmoscope. The wavefront aberration root mean square value without defocus did not significantly differ between model and living eyes. Higher order aberrations were slightly higher but RGC image quality was comparable to published in vivo work. Overall, the model allows a large reduction in number and duration of animal procedures required to develop new in vivo retinal imaging devices.

Random regression models for the prediction of days to weight, ultrasound rib eye area, and ultrasound back fat depth in beef cattle.

PubMed

Speidel, S E; Peel, R K; Crews, D H; Enns, R M

2016-02-01

Genetic evaluation research designed to reduce the required days to a specified end point has received very little attention in pertinent scientific literature, given that its economic importance was first discussed in 1957. There are many production scenarios in today's beef industry, making a prediction for the required number of days to a single end point a suboptimal option. Random regression is an attractive alternative to calculate days to weight (DTW), days to ultrasound back fat (DTUBF), and days to ultrasound rib eye area (DTUREA) genetic predictions that could overcome weaknesses of a single end point prediction. The objective of this study was to develop random regression approaches for the prediction of the DTW, DTUREA, and DTUBF. Data were obtained from the Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB, Canada. Data consisted of records on 1,324 feedlot cattle spanning 1999 to 2007. Individual animals averaged 5.77 observations with weights, ultrasound rib eye area (UREA), ultrasound back fat depth (UBF), and ages ranging from 293 to 863 kg, 73.39 to 129.54 cm, 1.53 to 30.47 mm, and 276 to 519 d, respectively. Random regression models using Legendre polynomials were used to regress age of the individual on weight, UREA, and UBF. Fixed effects in the model included an overall fixed regression of age on end point (weight, UREA, and UBF) nested within breed to account for the mean relationship between age and weight as well as a contemporary group effect consisting of breed of the animal (Angus, Charolais, and Charolais sired), feedlot pen, and year of measure. Likelihood ratio tests were used to determine the appropriate random polynomial order. Use of the quadratic polynomial did not account for any additional genetic variation in days for DTW ( > 0.11), for DTUREA ( > 0.18), and for DTUBF ( > 0.20) when compared with the linear random polynomial. Heritability estimates from the linear random regression for DTW ranged from 0.54 to 0

MC ray-tracing optimization of lobster-eye focusing devices with RESTRAX

NASA Astrophysics Data System (ADS)

Šaroun, Jan; Kulda, Jiří

2006-11-01

The enhanced functionalities of the latest version of the RESTRAX software, providing a high-speed Monte Carlo (MC) ray-tracing code to represent a virtual three-axis neutron spectrometer, include representation of parabolic and elliptic guide profiles and facilities for numerical optimization of parameter values, characterizing the instrument components. As examples, we present simulations of a doubly focusing monochromator in combination with cold neutron guides and lobster-eye supermirror devices, concentrating a monochromatic beam to small sample volumes. A Levenberg-Marquardt minimization algorithm is used to optimize simultaneously several parameters of the monochromator and lobster-eye guides. We compare the performance of optimized configurations in terms of monochromatic neutron flux and energy spread and demonstrate the effect of lobster-eye optics on beam transformations in real and momentum subspaces.

Exploratory Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Law. J.; Alexander, D.; Ryder, V. Myers;

Interacting with mobile devices by fusion eye and hand gestures recognition systems based on decision tree approach

NASA Astrophysics Data System (ADS)

Elleuch, Hanene; Wali, Ali; Samet, Anis; Alimi, Adel M.

2017-03-01

Two systems of eyes and hand gestures recognition are used to control mobile devices. Based on a real-time video streaming captured from the device's camera, the first system recognizes the motion of user's eyes and the second one detects the static hand gestures. To avoid any confusion between natural and intentional movements we developed a system to fuse the decision coming from eyes and hands gesture recognition systems. The phase of fusion was based on decision tree approach. We conducted a study on 5 volunteers and the results that our system is robust and competitive.

Biometric measurements in highly myopic eyes.

PubMed

Shen, Peiyang; Zheng, Yingfeng; Ding, Xiaohu; Liu, Bin; Congdon, Nathan; Morgan, Ian; He, Mingguang

2013-02-01

To assess the repeatability and accuracy of optical biometry (Lenstar LS900 optical low-coherence reflectometry [OLCR] and IOLMaster partial coherence interferometry [PCI]) and applanation ultrasound biometry in highly myopic eyes. Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Guangzhou, China. Comparative evaluation of diagnostic technology. Biometric measurements were taken in highly myopic subjects with a spherical equivalent (SE) of -6.00 diopters (D) or higher and an axial length (AL) longer than 25.0 mm. Measurements of AL and anterior chamber depth (ACD) obtained by OLCR were compared with those obtained by PCI and applanation A-scan ultrasound. Right eyes were analyzed. Repeatability was evaluated using the coefficient of variation (CoV) and agreement, using Bland-Altman analyses. The mean SE was -11.20 D ± 4.65 (SD). The CoVs for repeated AL measurements using OLCR, PCI, and applanation ultrasound were 0.06%, 0.07%, and 0.20%, respectively. The limits of agreement (LoA) for AL were 0.11 mm between OLCR and PCI, 1.01 mm between OLCR and applanation ultrasound, and 1.03 mm between PCI and ultrasound. The ACD values were 0.29 mm, 0.53 mm, and 0.51 mm, respectively. These repeatability and agreement results were comparable in eyes with extreme myopia (AL ≥ 27.0 mm) or posterior staphyloma. The mean radius of corneal curvature was similar between OLCR and PCI (7.66 ± 0.24 mm versus 7.64 ± 0.25 mm), with an LoA of 0.12 mm. Optical biometry provided more repeatable and precise measurements of biometric parameters, including AL and ACD, than applanation ultrasound biometry in highly myopic eyes. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Treatment of glaucoma with high intensity focused ultrasound.

PubMed

Aptel, Florent; Lafon, Cyril

2015-05-01

Glaucoma is a common disease mainly due to an increase in pressure inside the eye, leading to a progressive destruction of the optic nerve, potentially to blindness. Intraocular pressure (IOP) is the result of a balance between production of liquid that fills the eye--aqueous humour--and its resorption. All treatments for glaucoma aim to reduce IOP and can therefore have two mechanisms of action: reducing aqueous humour production by the partial destruction or medical inhibition of the ciliary body--the anatomical structure responsible for production of aqueous humour--or facilitating the evacuation of aqueous humour from the eye. Several physical methods can be used to destroy the ciliary body, e.g. laser, cryotherapy, microwave. All these methods have two major drawbacks: they are non-selective for the organ to be treated and they have an unpredictable dose–effect relationship. High intensity focused ultrasound (HIFU) can be used to coagulate the ciliary body and avoid these drawbacks. A commercially available device was marketed in the 1980s, but later abandoned, essentially for technical reasons. A smaller circular device using miniaturised transducers was recently developed and proposed for clinical practice. Experimental studies have shown selective coagulation necrosis of the treated ciliary body. The first three clinical trials in humans have shown that this device was well tolerated and allowed a significant, predictable and sustained reduction of IOP. The aim of this contribution is to present a summary of the work concerning the use of HIFU to treat glaucoma.

Carotid Doppler ultrasound findings in patients with left ventricular assist devices.

PubMed

Cervini, Patrick; Park, Soon J; Shah, Dipesh K; Penev, Irina E; Lewis, Bradley D

2010-12-01

Left ventricular assist devices (LVADs) have been used to treat advanced heart failure refractory to medical management, as bridge therapy to myocardial recovery, as bridge therapy to cardiac transplantation, or as destination therapy for patients with unfavorable transplant candidacy. Neurologic complications are some of the most common and devastating complications in these patients. Preoperative carotid ultrasound is, therefore, a standard evaluation in patients at risk for cerebrovascular disease. Postoperative carotid artery Doppler sonography is performed in those patients with neurologic symptoms. It is likely, therefore, that sonographers, radiologists, and other physicians working in a center where LVADs are implanted will likely encounter a carotid artery Doppler study in this patient group. To our knowledge, the carotid Doppler findings in these patients have never been published. We review the Doppler ultrasound findings in 6 patients after LVAD insertion.

Evaluation of an eye-pointer interaction device for human-computer interaction.

PubMed

Cáceres, Enrique; Carrasco, Miguel; Ríos, Sebastián

2018-03-01

Advances in eye-tracking technology have led to better human-computer interaction, and involve controlling a computer without any kind of physical contact. This research describes the transformation of a commercial eye-tracker for use as an alternative peripheral device in human-computer interactions, implementing a pointer that only needs the eye movements of a user facing a computer screen, thus replacing the need to control the software by hand movements. The experiment was performed with 30 test individuals who used the prototype with a set of educational videogames. The results show that, although most of the test subjects would prefer a mouse to control the pointer, the prototype tested has an empirical precision similar to that of the mouse, either when trying to control its movements or when attempting to click on a point of the screen.

A History of the Sonocare CST-100: The First FDA-approved HIFU Device

NASA Astrophysics Data System (ADS)

Muratore, Robert

2006-05-01

The Sonocare CST-100 Therapeutic Ultrasound System, designed for the treatment of glaucoma, was developed in the 1980s and became the first high intensity focused ultrasound (HIFU) device to receive Food and Drug Administration approval. The system arose from studies done by F.L. Lizzi, Eng.Sc.D., of Riverside Research Institute and D.J. Coleman, M.D., of Cornell Medical Center/New York Hospital on the safety of ultrasound diagnosis of the eye. As safety limits were probed, therapeutic regimes were discovered. Optimization of operational parameters, clinical experience, and engineering design came together through a spin-off company, Sonocare, Inc., formed to produce and market the ophthalmic device. Various precedents were set during the approval process, including the acceptance by the FDA of radiation momentum imparted to an absorber as a measure of acoustic power. Many devices were sold, but the laser industry, grandfathered into the therapeutic field, eventually out-marketed Sonocare. The CST-100 remains as a model of elegant industrial design, and existing units are used daily in HIFU laboratory experiments.

A portable device for measuring donor corneal transparency in eye banks.

PubMed

Parekh, Mohit; Ferrari, Stefano; Ruzza, Alessandro; Pugliese, Mariarosaria; Ponzin, Diego; Salvalaio, Gianni

2014-03-01

To develop a portable device for measuring the donor corneal transparency and validate its efficacy for corneal evaluation in the eye-banks and for research. The transparency device (TD) has a light source, a detachable system for corneal insertion and a base for light transmission. The probe detects the transmitted light which is measured by a lux-meter. A contact lens was set as 'control' to reduce the light scattering concern, an empty petri-plate as 'blank' and the cornea as 'sample'. Two experts and non-experts (masked) observed the corneas for subjective analysis which was then compared using the TD. The parameters observed were scars, foreign-body, stromal-deformities, folds, thickness and opacity which were then converted to a relative overall percentage by the observer. Twenty corneas were evaluated for correlation, five tissues to obtain standard-deviation and twenty-four pairs for a comparative study. Experts mimicked the eye-banks with long-term experience while non-experts mimicked the emerging eye-banks. Subjective values by the experts closely resembled the measurements by TD. The average correlation between the experts and the non-experts to TD was 0.985 and 0.960 respectively. TD showed higher reproducibility than experts followed by the non-experts. The comparative study showed that increase in thickness reduces the transparency. TD is portable, easy, efficient, maintains sterility and less expensive hence the emerging eye-banks and researchers can use to raise their standards and evaluate the transparency for in vitro tests and comparative studies. The suitable transparency for the cornea deemed for clinical applications was found to be >75 %.

[Evolution of nodular scleritis with ultrasound biomicroscopy: case report].

PubMed

Martinez, Andrea Alejandra Gonzalez; Matos, Kimble Teixeira Fonseca; Trevisani, Virgínia; Hirai, Alcides; Allemann, Norma

2013-01-01

To establish evolutionary pattern of a case of nodular scleritis with high frequency ultrasound during treatment. Twenty-seven year old female, initial manifestation of intermediate uveitis, bilateral macular edema after clinical treatment with topical and oral steroids. After four months, we observed the formation of a scleral nodule in the right eye when patient underwent high frequency ultrasound (Paradigm, 50 MHz transducer, immersion technique). The lesion in right eye was characterized at high frequency ultrasound as a nodular lesion located at the anterior inferior temporal wall associated with localized reduction of scleral thickness. After intravitreal injection of triamcinolone for treatment of macular edema, clinical regression of the scleral nodule was observed in right eye, maintaining reduced scleral thickness. High frequency ultrasound assisted in the diagnosis of nodular scleritis during the phases of treatment and in the identify its characteristic sequel feature, the scleral thinning.

Ultrasound detection of cavitation as a phenomenon common to intervention devices causing tissue ablation

NASA Astrophysics Data System (ADS)

Bach, David S.; Armstrong, William F.; Erbel, Raimund; Ellis, Stephen G.; Sousa, Joao; Rosenschein, Uri

1992-08-01

Cavitation previously has been observed in association with ultrasonic angioplasty and high- frequency rotational atherectomy. This study evaluates the production of cavitation accompanying the use of several catheter-based devices under development or in current use in the practice of interventional cardiology. Catheters were examined in an in vitro model, and cavitation was evaluated using standard ultrasound imaging equipment. Cavitation was detected with each of the devices that effects tissue ablation, but not tissue resection. Devices produced characteristic patterns of cavitation dependent on the mode of energy release of the device. The size, but not the intensity, of the cavitation effect was proportional to the energy output of the devices. The precise role of cavitation in the mechanism of tissue ablation remains uncertain.

Fast Track ultrasound protocol to detect acute complications after totally implantable venous access device placement.

PubMed

Wu, Chun-Yu; Lin, Feng-Sheng; Wang, Yi-Chia; Chou, Wei-Han; Lin, Wen-Ying; Sun, Wei-Zen; Lin, Chih-Peng

2015-01-01

The role of ultrasound examination in detection of postprocedure complications from totally implantable venous access devices (TIVAD) placement is still uncertain. In a cohort of 665 cancer outpatients, we assessed a quick ultrasound examination protocol in early detection of mechanical complications of catheterization. Immediately after TIVAD placement, an ultrasound examination and chest radiography were performed to detect hemothorax, pneumothorax, and catheter malposition. The two methods were compared. Of the 668 catheters inserted, 628 were placed into axillary veins and 40 into internal jugular veins. The ultrasound examination took 2.5 ± 1.1 min. No hemothorax was detected, and neither pneumothorax nor catheter malposition was evident among the 40 internal jugular vein cannulations. Ultrasound and chest radiography examinations of the 628 axillary vein cannulations detected five and four instances of pneumothorax, respectively. Ultrasound detected all six catheter malpositions into the internal jugular vein. However, ultrasound failed to detect two out of three malpositions in the contralateral brachiocephalic vein and one kinking inside the superior vena cava. Without revision surgery, the operating time was 34.1 ± 15.6 min. With revision surgery, the operating time was shorter when ultrasound detected catheter malposition than when chest radiography was used (96.8 ± 12.9 vs. 188.8 ± 10.3 min, p < 0.001). Postprocedure ultrasound examination is a quick and sensitive method to detect TIVAD-related pneumothorax. It also precisely detects catheter malposition to internal jugular vein thus reduces time needed for revision surgery while chest radiography remains necessary to confirm catheter final position.

Comparison of central corneal thickness measurements using ultrasound pachymetry, ultrasound biomicroscopy, and the Artemis-2 VHF scanner in normal eyes

PubMed Central

Al-Farhan, Haya M; Al-Otaibi, Wafa’a Majed

2012-01-01

Purpose To compare the precision of central corneal thickness (CCT) measurements taken with the handheld ultrasound pachymeter (USP), ultrasound biomicroscopy (UBM), and the Artemis-2 very high frequency ultrasound scanner (VHFUS) on normal subjects. Design Prospective study. Methods One eye from each of 61 normal subjects was randomly selected for this study. The measurements of the CCT were taken with the USP, VHFUS, and UBM. Results were compared statistically using repeated-measures analysis of variance (ANOVA), Pearson’s correlation coefficient, and limits of agreement. Results The average CCT (± standard deviation) was 530.1 ± 30.5 μm, 554.9 ± 31.7 μm, and 559.5 ± 30.7 μm for UBM, VHFUS, and USP respectively. The intraobserver repeatability analyses of variance are not significant for USP, UBM, and VHFUS. P-values were 0.17, 0.19, and 0.37 respectively. Repeated-measures ANOVA showed a significant difference between the three different methods of measuring CCT (P = 0.0001). The ANOVA test revealed no statistically significant difference between USP and VHFUS (P > 0.05), yet statistical significant differences with UBM versus USP and UBM versus VHFUS (P < 0.001). There were high correlations between the three instruments (P < 0.0001). The mean differences (and upper/lower limits of agreement) for CCT measurements were 29.4 ± 14.3 (2.7/56), 4.6 ± 8.6 (−14.7/23.8), and −24.8 ± 13.1 (−50.4/0.8) for USP versus UBM, USP versus VHFUS, and UBM versus VHFUS, respectively. Conclusion The UBM produces CCT measurements that vary significantly from those returned by the USP and the VHFUS, suggesting that the UBM may not be used interchangeably with either equipment for monitoring the CCT in the clinical setting. PMID:22848145

Transverse vs torsional ultrasound: prospective randomized contralaterally controlled study comparing two phacoemulsification-system handpieces

PubMed Central

Assil, Kerry K; Harris, Lindsay; Cecka, Jeannie

2015-01-01

Purpose To compare surgical efficiency and multiple early clinical outcome variables in eyes undergoing phacoemulsification using either transversal or torsional ultrasound systems. Setting Assil Eye Institute, Beverly Hills, CA, USA. Design Prospective, randomized, clinician-masked, contralaterally controlled single-center evaluation. Patients and methods Patients seeking cataract removal in both eyes with implantation of multifocal intraocular lenses were randomly assigned to one of two treatment rooms for phacoemulsification with either a transverse ultrasound system or torsional handpiece system. The contralateral eye was treated at a later date with the alternate device. A total of 54 eyes of 27 patients having similar degrees of cataract, astigmatism, and visual potential were included. All operative data were collected for analysis, and patients were followed for 3 months after surgery. Results Similar visual acuity was reported at all postoperative visits between the two groups. Mean phacoemulsification time and total power required were both significantly lower with the transverse system than with the torsional technique (P<0.05 for both). Similarly, mean total balanced salt solution used was significantly less with the transverse system vs torsional (P<0.05). Postoperative safety demonstrated significantly lower endothelial cell loss at 1 day and 1 month (P<0.05) with transverse vs torsional. Macular swelling was less at 1 week, 1 month, and 3 months with transverse vs torsional, although the difference did not achieve significance (P=0.1) at any single time point. Clinically detectable corneal edema was reported less frequently at all postoperative time points with the transverse system. Conclusion The transverse ultrasound system was found to be possibly associated with less balanced salt-solution use, less phacoemulsification time, and less power required than the torsional phaco system. Postoperative data suggested that improved phaco efficiency may

Transverse vs torsional ultrasound: prospective randomized contralaterally controlled study comparing two phacoemulsification-system handpieces.

PubMed

Assil, Kerry K; Harris, Lindsay; Cecka, Jeannie

2015-01-01

To compare surgical efficiency and multiple early clinical outcome variables in eyes undergoing phacoemulsification using either transversal or torsional ultrasound systems. Assil Eye Institute, Beverly Hills, CA, USA. Prospective, randomized, clinician-masked, contralaterally controlled single-center evaluation. Patients seeking cataract removal in both eyes with implantation of multifocal intraocular lenses were randomly assigned to one of two treatment rooms for phacoemulsification with either a transverse ultrasound system or torsional handpiece system. The contralateral eye was treated at a later date with the alternate device. A total of 54 eyes of 27 patients having similar degrees of cataract, astigmatism, and visual potential were included. All operative data were collected for analysis, and patients were followed for 3 months after surgery. Similar visual acuity was reported at all postoperative visits between the two groups. Mean phacoemulsification time and total power required were both significantly lower with the transverse system than with the torsional technique (P<0.05 for both). Similarly, mean total balanced salt solution used was significantly less with the transverse system vs torsional (P<0.05). Postoperative safety demonstrated significantly lower endothelial cell loss at 1 day and 1 month (P<0.05) with transverse vs torsional. Macular swelling was less at 1 week, 1 month, and 3 months with transverse vs torsional, although the difference did not achieve significance (P=0.1) at any single time point. Clinically detectable corneal edema was reported less frequently at all postoperative time points with the transverse system. The transverse ultrasound system was found to be possibly associated with less balanced salt-solution use, less phacoemulsification time, and less power required than the torsional phaco system. Postoperative data suggested that improved phaco efficiency may translate to a better overall safety profile for the patient.

The effect of extended sensory range via the EyeCane sensory substitution device on the characteristics of visionless virtual navigation.

PubMed

Maidenbaum, Shachar; Levy-Tzedek, Shelly; Chebat, Daniel Robert; Namer-Furstenberg, Rinat; Amedi, Amir

2014-01-01

Mobility training programs for helping the blind navigate through unknown places with a White-Cane significantly improve their mobility. However, what is the effect of new assistive technologies, offering more information to the blind user, on the underlying premises of these programs such as navigation patterns? We developed the virtual-EyeCane, a minimalistic sensory substitution device translating single-point-distance into auditory cues identical to the EyeCane's in the real world. We compared performance in virtual environments when using the virtual-EyeCane, a virtual-White-Cane, no device and visual navigation. We show that the characteristics of virtual-EyeCane navigation differ from navigation with a virtual-White-Cane or no device, and that virtual-EyeCane users complete more levels successfully, taking shorter paths and with less collisions than these groups, and we demonstrate the relative similarity of virtual-EyeCane and visual navigation patterns. This suggests that additional distance information indeed changes navigation patterns from virtual-White-Cane use, and brings them closer to visual navigation.

[Pharmacokinetics of radiotracers in the ocular tissues exposed to infrasound and ultrasound phonophoreses].

PubMed

2006-01-01

The paper compares the efficiency of infrasound and ultrasound phonophoreses. The efficiency was evaluated on the basis of the rate of radiotracers within the eye after infrasound or ultrasound exposure of the eyeball. The exposure was made after preliminary putting the radiotracer-impregnated application into the bulbar conjunctiva of an animal. Radioactivity was recorded on a Siemens gamma camera in its lifetime. The time course of changes in the radioactivities measured 10, 30, and 60 minutes after termination of exposures strongly suggests its stable increase in the eye exposed to infrasound. At the same time 10 minutes after ultrasound exposure, the increased concentration of a radiotracer in the eye was less than that after infrasound exposure and then it progressively decreased. Thus, having a significant phoretic activity, infrasound, as ultrasound, creates more favorable conditions for long drug storage in the eye.

Ultrasound microscope: the new field in ultrasound diagnostics

NASA Astrophysics Data System (ADS)

Novyc'kyy, Victor V.; Lushchyk, Ulyana B.

2001-06-01

A device which is a new stage in the development of medical equipment has been developed. The device works as an ultrasound microscope in vivo and provides 4 up to 32 colored histological image. It gives possibility to estimate tissue acoustic density with the help of 4 up to 32 gradation coloring different tissues and enables tissue microcirculation visualization. With the help of the device a doctor can objectify fatty hepatitis and cirrhosis, edema of different organs and tissues as well as microcirculation in organs and tissues (e.g. muscles, myocard and bone system). New promising applications of ultrasound systems in diagnostics and for choosing individual treatment tactics, with pathogenesis being taken into account, may be developed with the help of the device.

Ocular examination for trauma; clinical ultrasound aboard the International Space Station.

PubMed

Chiao, Leroy; Sharipov, Salizhan; Sargsyan, Ashot E; Melton, Shannon; Hamilton, Douglas R; McFarlin, Kellie; Dulchavsky, Scott A

2005-05-01

Ultrasound imaging is a successful modality in a broad variety of diagnostic applications including trauma. Ultrasound has been shown to be accurate when performed by non-radiologist physicians; recent reports have suggested that non-physicians can perform limited ultrasound examinations. A multipurpose ultrasound system is installed on the International Space Station (ISS) as a component of the Human Research Facility (HRF). This report documents the first ocular ultrasound examination conducted in space, which demonstrated the capability to assess physiologic alterations or pathology including trauma during long-duration space flight. An ISS crewmember with minimal sonography training was remotely guided by an imaging expert from Mission Control Center (MCC) through a comprehensive ultrasound examination of the eye. A multipurpose ultrasound imager was used in conjunction with a space-to-ground video downlink and two-way audio. Reference cards with topological reference points, hardware controls, and target images were used to facilitate the examination. Multiple views of the eye structures were obtained through a closed eyelid. Pupillary response to light was demonstrated by modifying the light exposure of the contralateral eye. A crewmember on the ISS was able to complete a comprehensive ocular examination using B- and M-mode ultrasonography with remote guidance from an expert in the MCC. Multiple anteroposterior, oblique, and coronal views of the eye clearly demonstrated the anatomic structures of both segments of the globe. The iris and pupil were readily visualized with probe manipulation. Pupillary diameter was assessed in real time in B- and M-mode displays. The anatomic detail and fidelity of ultrasound video were excellent and could be used to answer a variety of clinical and space physiologic questions. A comprehensive, high-quality ultrasound examination of the eye was performed with a multipurpose imager aboard the ISS by a non-expert operator using

Ocular examination for trauma; clinical ultrasound aboard the International Space Station

NASA Technical Reports Server (NTRS)

Chiao, Leroy; Sharipov, Salizhan; Sargsyan, Ashot E.; Melton, Shannon; Hamilton, Douglas R.; McFarlin, Kellie; Dulchavsky, Scott A.

2005-01-01

BACKGROUND: Ultrasound imaging is a successful modality in a broad variety of diagnostic applications including trauma. Ultrasound has been shown to be accurate when performed by non-radiologist physicians; recent reports have suggested that non-physicians can perform limited ultrasound examinations. A multipurpose ultrasound system is installed on the International Space Station (ISS) as a component of the Human Research Facility (HRF). This report documents the first ocular ultrasound examination conducted in space, which demonstrated the capability to assess physiologic alterations or pathology including trauma during long-duration space flight. METHODS: An ISS crewmember with minimal sonography training was remotely guided by an imaging expert from Mission Control Center (MCC) through a comprehensive ultrasound examination of the eye. A multipurpose ultrasound imager was used in conjunction with a space-to-ground video downlink and two-way audio. Reference cards with topological reference points, hardware controls, and target images were used to facilitate the examination. Multiple views of the eye structures were obtained through a closed eyelid. Pupillary response to light was demonstrated by modifying the light exposure of the contralateral eye. RESULTS: A crewmember on the ISS was able to complete a comprehensive ocular examination using B- and M-mode ultrasonography with remote guidance from an expert in the MCC. Multiple anteroposterior, oblique, and coronal views of the eye clearly demonstrated the anatomic structures of both segments of the globe. The iris and pupil were readily visualized with probe manipulation. Pupillary diameter was assessed in real time in B- and M-mode displays. The anatomic detail and fidelity of ultrasound video were excellent and could be used to answer a variety of clinical and space physiologic questions. CONCLUSIONS: A comprehensive, high-quality ultrasound examination of the eye was performed with a multipurpose imager

Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Schaefer, C.; Coble, C.; Mason, S.; Young, M.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Patel, N.; Gibson, C.; Alexander, D.;

Portable Bladder Ultrasound

PubMed Central

2006-01-01

L are considered an indication for urinary retention, requiring intermittent catheterization, whereas a PVR urine volume of 100 mL to 150 mL or less is generally considered an acceptable result of bladder training. Urinary retention has been associated with poor outcomes including UTI, bladder overdistension, and higher hospital mortality rates. The standard method of determining PVR urine volumes is intermittent catheterization, which is associated with increased risk of UTI, urethral trauma and discomfort. The Technology Being Reviewed Portable bladder ultrasound products are transportable ultrasound devices that use automated technology to register bladder volume digitally, including PVR volume, and provide three-dimensional images of the bladder. The main clinical use of portable bladder ultrasound is as a diagnostic aid. Health care professionals (primarily nurses) administer the device to measure PVR volume and prevent unnecessary catheterization. An adjunctive use of the bladder ultrasound device is to visualize the placement and removal of catheters. Also, portable bladder ultrasound products may improve the diagnosis and differentiation of urological problems and their management and treatment, including the establishment of voiding schedules, study of bladder biofeedback, fewer UTIs, and monitoring of potential urinary incontinence after surgery or trauma. Review Strategy To determine the effectiveness and clinical utility of portable bladder ultrasound as reported in the published literature, the Medical Advisory Secretariat used its standard search strategy to retrieve international health technology assessments and English-language journal articles from selected databases. Nonsystematic reviews, nonhuman studies, case reports, letters, editorials, and comments were excluded. Summary of Findings Of the 4 included studies that examined the clinical utility of portable bladder ultrasound in the elderly population, all found the device to be acceptable. One

Annular phased-array high-intensity focused ultrasound device for image-guided therapy of uterine fibroids.

PubMed

Held, Robert Thomas; Zderic, Vesna; Nguyen, Thuc Nghi; Vaezy, Shahram

2006-02-01

An ultrasound (US), image-guided high-intensity focused ultrasound (HIFU) device was developed for noninvasive ablation of uterine fibroids. The HIFU device was an annular phased array, with a focal depth range of 30-60 mm, a natural focus of 50 mm, and a resonant frequency of 3 MHz. The in-house control software was developed to operate the HIFU electronics drive system for inducing tissue coagulation at different distances from the array. A novel imaging algorithm was developed to minimize the HIFU-induced noise in the US images. The device was able to produce lesions in bovine serum albumin-embedded polyacrylamide gels and excised pig liver. The lesions could be seen on the US images as hyperechoic regions. Depths ranging from 30 to 60 mm were sonicated at acoustic intensities of 4100 and 6100 W/cm2 for 15 s each, with the latter producing average lesion volumes at least 63% larger than the former. Tissue sonication patterns that began distal to the transducer produced longer lesions than those that began proximally. The variation in lesion dimensions indicates the possible development of HIFU protocols that increase HIFU throughput and shorten tumor treatment times.

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

Comparison of IOL--master and ultrasound biometry in preoperative intra ocular lens (IOL) power calculation.

PubMed

Kolega, Marija Škara; Kovačević, Suzana; Čanović, Samir; Pavičić, Ana Didović; Bašić, Jadranka Katušić

2015-03-01

Postoperative refractive outcome largely depends on the accuracy of calculating power of implanted IOL. Lens power calculation can be done by conventional ultrasound biometry and partial coherence laser interferometry (IOL Master). The aim was to compare the accuracy of IOL power calculations using conventional ultrasound biometry and partial coherence laser interferometry.40 eyes were included in this prospective randomized trial. Twenty eyes underwent IOL master and 20 eyes had aplanation ultrasound biometry. There were included only eyes with age-related cataract and postoperative natural visual acuity (VA) 0.7. Visual acuity was performed 6 weeks after cataract surgery. After 6 weeks best natural visual acuity were 0.9 (± 0.1) in IOL-Master group and 0.85 (± 0.15) in ultrasound biometry. The postoperative mean absolute refractive error was 0.75 (± 0.5) D for ultrasound biometry and 0.50 (± 0.50) D for IOL-Master. Optical biometry with the IOL-Master proved to be slightly more accurate than ultrasound biometry for IOL power calculation.

Ultrasound biomicroscopy. High-frequency ultrasound imaging of the eye at microscopic resolution.

PubMed

Pavlin, C J; Foster, F S

1998-11-01

UBM presents us with a new method of imaging the anterior segment of the eye at high resolution. Its strengths lie in its ability to produce cross-sections of the living eye at microscopic resolution without violating the integrity of the globe. UBM, although lacking the resolution of optical microscopy, gives us images in living eyes without affecting the internal relationships of the structures imaged. There are many other applications of this new imaging method. Examples of other uses include imaging adnexal pathology, assessing corneal changes with refractive surgery, the assessment of trauma, and determination of intraocular lens position.

21 CFR 886.4750 - Ophthalmic eye shield.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a plastic or aluminum eye covering intended to...

21 CFR 886.4750 - Ophthalmic eye shield.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a plastic or aluminum eye covering intended to...

21 CFR 886.3200 - Artificial eye.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to be...

21 CFR 886.3200 - Artificial eye.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a device resembling the anterior portion of the eye, usually made of glass or plastic, intended to be...

Comparison of Two Devices for Intraoperative Portal Venous Flow Measurement in Living-Donor Liver Transplantation: Transit Time Ultrasound and Conventional Doppler Ultrasound.

PubMed

Wang, H-K; Chen, C-Y; Lin, N-C; Liu, C-S; Loong, C-C; Lin, Y-H; Lai, Y-C; Chiou, H-J

2018-05-01

Intraoperative portal venous flow measurement provides surgeons with instant guidance for portal flow modulation during living-donor liver transplantation (LDLT). In this study, we compared the agreement of portal flow measurement obtained by 2 devices: transit time ultrasound (TTU) and conventional Doppler ultrasound (CDU). Fifty-four recipients of LDLT underwent intraoperative measurement of portal flow after completion of vascular anastomosis of the implanted partial liver graft. Both TTU and CDU were used concurrently. Agreement of TTU and CDU was assessed by intraclass correlation coefficient using a model of 2-way random effects, absolute agreement, and single measurement. A Bland-Altman plot was applied to assess the variability between the 2 devices. The mean, median, and range of portal venous flow was 1456, 1418, and 117 to 2776 mL/min according to TTU; and 1564, 1566, and 119 to 3216 mL/min according to CDU. The intraclass correlation coefficient of portal venous flow between TTU and CDU was 0.68 (95% confidence interval, 0.51-0.80). The Bland-Altman plots revealed an average variation of 4.8% between TTU and CDU but with a rather wide 95% confidence interval of variation ranging from -57.7% to 67.4%. Intraoperative TTU and CDU showed moderate agreement in portal flow measurement. However, a relatively wide range of variation exists between TTU and CDU, indicating that data obtained from the 2 devices may not be interchangeable. Copyright © 2018 Elsevier Inc. All rights reserved.

[Validation of a new hand-carried ultrasound device equipped with directional color power Doppler and continuous wave Doppler].

PubMed

Kawai, Junichi; Tanabe, Kazuaki; Matsuzaki, Masashi; Yamaguchi, Kazuto; Yagi, Toshikazu; Fujii, Yoko; Konda, Toshiko; Ui, Kazuyo; Sumida, Toshiaki; Okada, Midori; Tani, Tomoko; Morioka, Shigefumi

2003-10-01

This study evaluated the accuracy of the directional color power Doppler (DCPD) and continuous wave Doppler (CWD) methods incorporated in the new hand-carried SonoSite 180PLUS ultrasound device. The hand-held ultrasound system with 2.5 MHz transducer and SONOS 5500 was used as a standard ultrasound system with a 2 to 4 MHz wideband transducer. The experimental study used a Doppler wire phantom to evaluate the influence of target wire speed and angle of transducer on DCPD imaging. The clinical study included 48 consecutive patients. DCPD assessment of valvular regurgitation measured the distances of DCPD signals of mitral, aortic and tricuspid valve regurgitation using the apical four-chamber view for comparison with standard echocardiography. CWD assessment measured the peak velocities of the aortic flow and tricuspid valve regurgitant flow for comparison with standard echocardiography. In the experimental study, DCPD signals were not influenced by target wire speed changes and transducer incident angles. In the clinical study, agreements for mitral, aortic and tricuspid regurgitation between the two methods were 89.6%, 81.8% and 78.7%, respectively. The distances of DCPD valve regurgitant signals by the hand-carried ultrasound device showed good correlation (mitral regurgitation: y = 0.84x + 0.55; r = 0.93, aortic regurgitation: y = 0.95x + 0.27; r = 0.94, tricuspid regurgitation: y = 0.86x + 0.61; r = 0.90) with those by standard echocardiography. Evaluation of CWD velocity measurements showed good agreement for the lower flow velocities (< 2.0 m/sec). However, underestimation occurred for the high flow velocities (> 2.0 m/sec) compared with those by standard echocardiography (aortic flow: y = 0.80x + 0.11; r = 0.95, tricuspid regurgitation: y = 1.00x - 0.23; r = 0.90). The new hand-carried ultrasound device (SonoSite 180PLUS equipped with DCPD and CWD) is clinically useful for evaluating valvular regurgitations and flow velocities. Further studies are needed to

Eyes as fenestrations to the ears: a novel mechanism for high-frequency and ultrasonic hearing.

PubMed

Lenhardt, Martin L

2007-01-01

Intense airborne ultrasound has been associated with hearing loss, tinnitus, and various nonauditory subjective effects, such as headaches, dizziness, and fullness in the ear. Yet, when people detect ultrasonic components in music, ultrasound adds to the pleasantness of the perception and evokes changes in the brain as measured in electroencephalograms, behavior, and imaging. How does the airborne ultrasound get into the ear to create such polar-opposite human effects? Surprisingly, ultrasound passes first through the eyes; thus, the eye becomes but another window into the inner ear.

Practical application to composite materials of a portable digital ultrasound device controlled by a microprocessor

NASA Astrophysics Data System (ADS)

Castel, J. G.; Husarek, V.

1987-06-01

The usefulness of a portable microprocessor-controlled ultrasound device for the periodic assessment of aircraft parts made of composite materials is shown. The performance of the device is demonstrated with the examples of a metallic honeycomb with a carbon-fiber skin, a phenolic honeycomb with a carbon skin, and a phenolic honeycomb with a Kevlar skin. Also considered are assessments of homogeneous carbon-fiber parts, including the study of artificial defects consisting of 1-2 mm diameter holes, and the assessment of the behavior of a carbon-titanium interface with separated zones. Advantages of the device include ease of adjustment, automated evaluation of the depth of defects, and the nearly-absolute reproducibility of adjustments.

Evaluation of the Tobii EyeX Eye tracking controller and Matlab toolkit for research.

PubMed

Gibaldi, Agostino; Vanegas, Mauricio; Bex, Peter J; Maiello, Guido

2017-06-01

The Tobii Eyex Controller is a new low-cost binocular eye tracker marketed for integration in gaming and consumer applications. The manufacturers claim that the system was conceived for natural eye gaze interaction, does not require continuous recalibration, and allows moderate head movements. The Controller is provided with a SDK to foster the development of new eye tracking applications. We review the characteristics of the device for its possible use in scientific research. We develop and evaluate an open source Matlab Toolkit that can be employed to interface with the EyeX device for gaze recording in behavioral experiments. The Toolkit provides calibration procedures tailored to both binocular and monocular experiments, as well as procedures to evaluate other eye tracking devices. The observed performance of the EyeX (i.e. accuracy < 0.6°, precision < 0.25°, latency < 50 ms and sampling frequency ≈55 Hz), is sufficient for some classes of research application. The device can be successfully employed to measure fixation parameters, saccadic, smooth pursuit and vergence eye movements. However, the relatively low sampling rate and moderate precision limit the suitability of the EyeX for monitoring micro-saccadic eye movements or for real-time gaze-contingent stimulus control. For these applications, research grade, high-cost eye tracking technology may still be necessary. Therefore, despite its limitations with respect to high-end devices, the EyeX has the potential to further the dissemination of eye tracking technology to a broad audience, and could be a valuable asset in consumer and gaming applications as well as a subset of basic and clinical research settings.

Comparison of sound speed measurements on two different ultrasound tomography devices

NASA Astrophysics Data System (ADS)

Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

2014-03-01

Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the attenuation of sound speed secondary to breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data

Ophthalmic applications of laser-generated ultrasound

NASA Astrophysics Data System (ADS)

Payne, Peter A.; Sadr, Ali; Rosen, Emanuel S.; Dewhurst, Richard J.

2000-06-01

Laser-generated ultrasound has found a number of niche applications in non-destructive testing and evaluation and there is now a growing trend to examine potential applications for materials characterization in medicine. Conventional ultrasound techniques for measuring various important dimensions within the eye are in extensive use. However, one problem remains outstanding, which is that the dimensions of the cornea, anterior chamber and lens can be measured using a high frequency, high resolution transducer, but the dimensions of the overall eyeball (i.e., cornea to retina) have to be measured with a lower frequency transducer in order to achieve the necessary penetration. We have conducted a number of in vitro studies using bovine eyes to determine whether the use of laser induced ultrasound would be able to overcome the aforementioned problem. The results of these measurements will be presented, together with a discussion of the many difficulties that remain to be overcome. In addition, our studies involve the potential use of laser ultrasound to quantify the degree of cataract formation, both primary and secondary. This paper will also consider the work accomplished to data in this area.

Ultrasound-enhanced ocular delivery of dexamethasone sodium phosphate: an in vivo study

PubMed Central

2014-01-01

Background The eye's unique anatomy and its physiological and anatomical barriers can limit effective drug delivery into the eye. Methods An in vivo study was designed to determine the effectiveness and safety of ultrasound application in enhancing drug delivery in a rabbit model. Permeability of a steroid ophthalmic drug, dexamethasone sodium phosphate, was investigated in ultrasound- and sham-treated cases. For this study, an eye cup filled with dexamethasone sodium phosphate was placed on the cornea. Ultrasound was applied at intensity of 0.8 W/cm2 and frequency of 400 or 600 kHz for 5 min. The drug concentration in aqueous humor samples, collected 90 min after the treatment, was determined using chromatography methods. Light microscopy observations were done to determine the structural changes in the cornea as a result of ultrasound application. Results An increase in drug concentration in aqueous humor samples of 2.8 times (p < 0.05) with ultrasound application at 400 kHz and 2.4 times (p < 0.01) with ultrasound application at 600 kHz was observed as compared to sham-treated samples. Histological analysis showed that the structural changes in the corneas exposed to ultrasound predominantly consisted of minor epithelial disorganization. Conclusions Ultrasound application enhanced the delivery of an anti-inflammatory ocular drug, dexamethasone sodium phosphate, through the cornea in vivo. Ultrasound-enhanced ocular drug delivery appears to be a promising area of research with a potential future application in a clinical setting. PMID:24921047

Comparison of Two Different Ultrasound Devices Using Strain Elastography Technology in the Diagnosis of Breast Lesions Related to the Histologic Results.

PubMed

Farrokh, André; Schaefer, Fritz; Degenhardt, Friedrich; Maass, Nicolai

2018-05-01

This study was conducted to provide evidence that elastograms of two different devices and different manufacturers using the same technical approach provide the same diagnoses. A total of 110 breast lesions were prospectively analysed by two experts in ultrasound, using the strain elastography function from two different manufacturers (Hitachi HI-RTE, Hitachi Medical Systems, Wiesbaden, Germany; and Siemens eSie Touch, Siemens Medical Systems, Erlangen, Germany). Results were compared with the histopathologic results. Applying the Bowker test of symmetry, no statistically significant difference between the two elastography functions of these two devices was found (p = 0.120). The Cohen's kappa of k = 0.591 showed moderate strength of agreement between the two elastograms. The two examiners yielded moderate strength of agreement analysing the elastograms (Hitachi HI-RTE, k = 0.478; Siemens eSie Touch, k = 0.441). In conclusion, evidence is provided that elastograms of the same lesion generated by two different ultrasound devices equipped with a strain elastography function do not significantly differ. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

21 CFR 886.1510 - Eye movement monitor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Eye movement monitor. 886.1510 Section 886.1510...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1510 Eye movement monitor. (a) Identification. An eye movement monitor is an AC-powered device with an electrode intended to measure and record...

21 CFR 886.1510 - Eye movement monitor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Eye movement monitor. 886.1510 Section 886.1510...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1510 Eye movement monitor. (a) Identification. An eye movement monitor is an AC-powered device with an electrode intended to measure and record...

21 CFR 878.4440 - Eye pad.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is...

21 CFR 878.4440 - Eye pad.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is...

21 CFR 878.4440 - Eye pad.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is...

Computer/Mobile Device Screen Time of Children and Their Eye Care Behavior: The Roles of Risk Perception and Parenting.

PubMed

Chang, Fong-Ching; Chiu, Chiung-Hui; Chen, Ping-Hung; Miao, Nae-Fang; Chiang, Jeng-Tung; Chuang, Hung-Yi

2018-03-01

This study assessed the computer/mobile device screen time and eye care behavior of children and examined the roles of risk perception and parental practices. Data were obtained from a sample of 2,454 child-parent dyads recruited from 30 primary schools in Taipei city and New Taipei city, Taiwan, in 2016. Self-administered questionnaires were collected from students and parents. Fifth-grade students spend more time on new media (computer/smartphone/tablet: 16 hours a week) than on traditional media (television: 10 hours a week). The average daily screen time (3.5 hours) for these children exceeded the American Academy of Pediatrics recommendations (≤2 hours). Multivariate analysis results showed that after controlling for demographic factors, the parents with higher levels of risk perception and parental efficacy were more likely to mediate their child's eye care behavior. Children who reported lower academic performance, who were from non-intact families, reported lower levels of risk perception of mobile device use, had parents who spent more time using computers and mobile devices, and had lower levels of parental mediation were more likely to spend more time using computers and mobile devices; whereas children who reported higher academic performance, higher levels of risk perception, and higher levels of parental mediation were more likely to engage in higher levels of eye care behavior. Risk perception by children and parental practices are associated with the amount of screen time that children regularly engage in and their level of eye care behavior.

In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies

PubMed Central

Radziemski, Leon; Makin, Inder Raj S.

2015-01-01

Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10 – 15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5 hours of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants. PMID:26243566

The efficacy of a combination non-thermal focused ultrasound and radiofrequency device for noninvasive body contouring in Asians.

PubMed

Shek, Samantha Y N; Yeung, Chi K; Chan, Johnny C Y; Chan, Henry H L

2016-02-01

Several studies have been published on the first generation non-thermal focused ultrasound with an average improvement of 0-3.95 cm reported. We aim to investigate the efficacy of the second-generation non-thermal focused ultrasound device with a combined radiofrequency hand piece. With the addition of radiofrequency energy, the temperature of the adipose tissue is raised before focused ultrasound is applied. This facilitates the mechanical disruption of fat cells by focused ultrasound. Twenty subjects were recruited and underwent three treatments biweekly. Caliper reading, abdominal circumference, and standardized photographs were taken with the Vectra(®) system at all visits. We aim to have the subjects stand and hold the same position and the photograph taken after exhalation. Caliper and circumference measurements carry uncertainty. It is impossible to eliminate all uncertainties but can be improved by having the same trained physician assistant perform the measurement at the same site and taking an average of three readings. Pain score and satisfaction were recorded by means of the visual analogue scale. The efficacy is defined by a statistically significant improvement in circumferential improvement based on intention-to-treat analysis. Seventeen subjects completed the treatment schedule. Abdominal circumference showed statistically significant improvement at 2 weeks post-second treatment (P = 0.023) and almost all subsequent follow-ups. Caliper readings were statistically significant at 2 weeks post-second treatment (P = 0.013) and almost all follow-ups. The mean pain score reported was 2.3 on the visual analog scale and 6% were unsatisfied with the overall treatments. Six incidents of wheal formation appeared immediately after treatment all of which subsided spontaneously within several hours. The combination non-thermal focused ultrasound and radiofrequency device is effective for improving body contour in Asians. © 2015 Wiley Periodicals, Inc.

Eye Protection in Kansas Schools.

ERIC Educational Resources Information Center

Hay, Kenneth M.; And Others

A law passed by a state legislature requires that students in industrial arts shops and science laboratories must wear eye protective devices. Explanatory material presents the text of the bill and guidelines for implementation, including--(1) types of eye hazards, (2) types of protective devices, (3) administrating eye safety equipment, (4)…

High-intensity focused ultrasound treatment in patients with refractory glaucoma.

PubMed

Giannaccare, Giuseppe; Vagge, A; Gizzi, C; Bagnis, A; Sebastiani, S; Del Noce, C; Fresina, M; Traverso, C E; Campos, E C

2017-03-01

To assess the safety and efficacy of ultrasound coagulation of the ciliary body in refractory glaucoma. This prospective multicenter interventional study was conducted in two Italian university-affiliated glaucoma centers: St. Orsola-Malpighi Teaching Hospital (Bologna, Italy) and University Eye Clinic of Genoa (Genoa, Italy). The main inclusion criterion was the diagnosis of glaucoma with a baseline intraocular pressure (IOP) ≥ 21 mmHg while on maximum topical and systemic medical hypotensive treatment. The EyeOP1 device (Eye Tech Care, Rillieux-la-Pape, France), which was employed in the study, uses miniaturized transducers to produce high-intensity focused ultrasound (HIFU). Treatment consisted of the sequential activation of each transducer lasting 4 s (group 1), 6 s (group 2) or 8 s (group 3). Hypotensive medications were interrupted after surgery and then prescribed only if postoperative IOP was ≥ 21 mmHg during follow-up visits. Patients were assessed before and 1, 7, 14, 30, 90 and 180 days after the procedure. Primary outcomes were the mean IOP reduction in the overall population and in groups 1, 2 and 3, and the rates of complete success, qualified success and failure. Thirty eyes (16 open-angle, 10 angle-closure and 4 neovascular glaucoma) of 30 patients were included. The mean preoperative IOP was 30.1 ± 10.5 mmHg. Twenty-nine patients completed the entire study follow-up; one patient exited from the study 3 months after HIFU and underwent trabeculectomy. At days 1 and 180, the mean IOP was significantly reduced (18.4 ± 7.2 and 20.2 ± 6.2 mmHg, respectively; all p < 0.0001). Group 3 patients (8-s ultrasound exposure time) showed a greater IOP reduction than the other two groups (-16.2 ± 8.3 for group 3 vs. -8.8 ± 6.6 for group 2 and -3.7 ± 6.5 for group 1; p = 0.02 and p < 0.001, respectively). Qualified and complete success was achieved in 23.3 and 46.7% of patients, respectively; treatment

Minimally-invasive Ultrasound Devices for Treating Low Back Pain

NASA Astrophysics Data System (ADS)

Nau, William; Diederich, C.; Shu, R.; Kinsey, A.; Lotz, J.; Ferrier, W.; Sutton, J.; Pellegrino, R.

2006-05-01

demonstrated with both applicator design configurations. Results from these studies demonstrated the capability to control temperature distributions within targeted regions of the disc using interstitial ultrasound with greater thermal penetration than can be achieved with the RF heating devices currently in clinical use. Thus interstitial ultrasound offers a potential alternative heating modality for the clinical management of low back pain.

A Disposable Microfluidic Device for Controlled Drug Release from Thermal-Sensitive Liposomes by High Intensity Focused Ultrasound.

PubMed

Meng, Long; Deng, Zhiting; Niu, Lili; Li, Fei; Yan, Fei; Wu, Junru; Cai, Feiyan; Zheng, Hairong

2015-01-01

The drug release triggered thermally by high intensity focused ultrasound (HIFU) has been considered a promising drug delivery strategy due to its localized energy and non-invasive characters. However, the mechanism underlying the HIFU-mediated drug delivery remains unclear due to its complexity at the cellular level. In this paper, micro-HIFU (MHIFU) generated by a microfluidic device is introduced which is able to control the drug release from temperature-sensitive liposomes (TSL) and evaluate the thermal and mechanical effects of ultrasound on the cellular drug uptake and apoptosis. By simply adjusting the input electrical signal to the device, the temperature of sample can be maintained at 37 °C, 42 °C and 50 °C with the deviation of ± 0.3 °C as desired. The flow cytometry results show that the drug delivery under MHIFU sonication leads to a significant increase in apoptosis compared to the drug release by incubation alone at elevated temperature of 42 °C. Furthermore, increased squamous and protruding structures on the surface membrane of cells were detected by atomic force microscopy (AFM) after MHIFU irradiation of TSL. We demonstrate that compared to the routine HIFU treatment, MHIFU enables monitoring of in situ interactions between the ultrasound and cell in real time. Furthermore, it can quantitatively analyze and characterize the alterations of the cell membrane as a function of the treatment time.

Ultrasound imaging of the anterior section of the eye of five different snake species.

PubMed

Lauridsen, Henrik; Da Silva, Mari-Ann O; Hansen, Kasper; Jensen, Heidi M; Warming, Mads; Wang, Tobias; Pedersen, Michael

2014-12-30

Nineteen clinically normal snakes: six ball pythons (Python regius), six Burmese pythons (Python bivittatus), one Children's python (Antaresia childreni), four Amazon tree boas (Corallus hortulanus), and two Malagasy ground boas (Acrantophis madagascariensis) were subjected to ultrasound imaging with 21 MHz (ball python) and 50 MHz (ball python, Burmese python, Children's python, Amazon tree boa, Malagasy ground boa) transducers in order to measure the different structures of the anterior segment in clinically normal snake eyes with the aim to review baseline values for clinically important ophthalmic structures. The ultrasonographic measurements included horizontal spectacle diameter, spectacle thickness, depth of sub-spectacular space and corneal thickness. For comparative purposes, a formalin-fixed head of a Burmese python was subjected to micro computed tomography. In all snakes, the spectacle was thinner than the cornea. There was significant difference in spectacle diameter, and spectacle and corneal thickness between the Amazon tree boa and the Burmese and ball pythons. There was no difference in the depth of the sub-spectacular space. The results obtained in the Burmese python with the 50 MHz transducer were similar to the results obtained with micro computed tomography. Images acquired with the 21 MHz transducer included artifacts which may be misinterpreted as ocular structures. Our measurements of the structures in the anterior segment of the eye can serve as orientative values for snakes examined for ocular diseases. In addition, we demonstrated that using a high frequency transducer minimizes the risk of misinterpreting artifacts as ocular structures.

21 CFR 878.4440 - Eye pad.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is... use as a bandage over the eye for protection or absorption of secretions. (b) Classification. Class I...

21 CFR 878.4440 - Eye pad.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is... use as a bandage over the eye for protection or absorption of secretions. (b) Classification. Class I...

Rodent wearable ultrasound system for wireless neural recording.

PubMed

Piech, David K; Kay, Joshua E; Boser, Bernhard E; Maharbiz, Michel M

2017-07-01

Advances in minimally-invasive, distributed biological interface nodes enable possibilities for networks of sensors and actuators to connect the brain with external devices. The recent development of the neural dust sensor mote has shown that utilizing ultrasound backscatter communication enables untethered sub-mm neural recording devices. These implanted sensor motes require a wearable external ultrasound interrogation device to enable in-vivo, freely-behaving neural interface experiments. However, minimizing the complexity and size of the implanted sensors shifts the power and processing burden to the external interrogator. In this paper, we present an ultrasound backscatter interrogator that supports real-time backscatter processing in a rodent-wearable, completely wireless device. We demonstrate a generic digital encoding scheme which is intended for transmitting neural information. The system integrates a front-end ultrasonic interface ASIC with off-the-shelf components to enable a highly compact ultrasound interrogation device intended for rodent neural interface experiments but applicable to other model systems.

Focused ultrasound in ophthalmology

PubMed Central

Silverman, Ronald H

2016-01-01

The use of focused ultrasound to obtain diagnostically significant information about the eye goes back to the 1950s. This review describes the historical and technological development of ophthalmic ultrasound and its clinical application and impact. Ultrasound, like light, can be focused, which is crucial for formation of high-resolution, diagnostically useful images. Focused, single-element, mechanically scanned transducers are most common in ophthalmology. Specially designed transducers have been used to generate focused, high-intensity ultrasound that through thermal effects has been used to treat glaucoma (via ciliodestruction), tumors, and other pathologies. Linear and annular transducer arrays offer synthetic focusing in which precise timing of the excitation of independently addressable array elements allows formation of a converging wavefront to create a focus at one or more programmable depths. Most recently, linear array-based plane-wave ultrasound, in which the array emits an unfocused wavefront and focusing is performed solely on received data, has been demonstrated for imaging ocular anatomy and blood flow. While the history of ophthalmic ultrasound extends back over half-a-century, new and powerful technologic advances continue to be made, offering the prospect of novel diagnostic capabilities. PMID:27757007

Focused ultrasound in ophthalmology.

PubMed

Silverman, Ronald H

2016-01-01

The use of focused ultrasound to obtain diagnostically significant information about the eye goes back to the 1950s. This review describes the historical and technological development of ophthalmic ultrasound and its clinical application and impact. Ultrasound, like light, can be focused, which is crucial for formation of high-resolution, diagnostically useful images. Focused, single-element, mechanically scanned transducers are most common in ophthalmology. Specially designed transducers have been used to generate focused, high-intensity ultrasound that through thermal effects has been used to treat glaucoma (via ciliodestruction), tumors, and other pathologies. Linear and annular transducer arrays offer synthetic focusing in which precise timing of the excitation of independently addressable array elements allows formation of a converging wavefront to create a focus at one or more programmable depths. Most recently, linear array-based plane-wave ultrasound, in which the array emits an unfocused wavefront and focusing is performed solely on received data, has been demonstrated for imaging ocular anatomy and blood flow. While the history of ophthalmic ultrasound extends back over half-a-century, new and powerful technologic advances continue to be made, offering the prospect of novel diagnostic capabilities.

21 CFR 886.3320 - Eye sphere implant.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Eye sphere implant. 886.3320 Section 886.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3320 Eye sphere implant. (a) Identification. An eye...

21 CFR 886.3320 - Eye sphere implant.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Eye sphere implant. 886.3320 Section 886.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3320 Eye sphere implant. (a) Identification. An eye...

Axial ultrasound B-scans of the entire eye with a 20-MHz linear array: correction of crystalline lens phase aberration by applying Fermat's principle.

PubMed

Mateo, Tony; Chang, Alexandre; Mofid, Yassine; Pisella, Pierre-Jean; Ossant, Frederic

2014-11-01

In ophthalmic ultrasonography the crystalline lens is known to be the main source of phase aberration, causing a significant decrease in resolution and distortion effects on axial B-scans. This paper proposes a computationally efficient method to correct the phase aberration arising from the crystalline lens, including refraction effects using a bending ray tracing approach based on Fermat's principle. This method is used as a basis to perform eye-adapted beamforming (BF), with appropriate focusing delays for a 128-element 20-MHz linear array in both emission and reception. Implementation was achieved on an in-house developed experimental ultrasound scanning device, the ECODERM. The proposed BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. Both extremes of accommodation shapes of the human crystalline lens were investigated. The performance of the developed BF was evaluated in relation to that in homogeneous medium and compared to a conventional delay-and-sum (DAS) BF and a second adapted BF which was simplified to ignore the lens refraction. Global expectations provided by our method with the transducer array are reviewed by an analysis quantifying both image quality and spatial fidelity, as well as the detrimental effects of a crystalline lens in conventional reconstruction. Compared to conventional array imaging, the results indicated a two-fold improvement in the lateral resolution, greater sensitivity and a considerable reduction of spatial distortions that were sufficient to envisage reliable biometry directly in B-mode, especially phakometry.

The efficacy of Ahmed glaucoma valve drainage devices in cases of adult refractory glaucoma in Indian eyes

PubMed Central

Parihar, Jitendra K S; Vats, Devendra P; Maggon, Rakesh; Mathur, Vijay; Singh, Anirudh; Mishra, Sanjay K

2009-01-01

Aim: To evaluate the efficacy of Ahmed glaucoma valve (AGV) drainage devices in cases of adult refractory glaucoma in Indian eyes. Settings and Design: Retrospective interventional case series study. Materials and Methods: Fifty two eyes of 32 patients of refractory glaucoma in the age group of 35 to 60 years who underwent AGV implantation with or without concomitant procedures from January 2003 to Jan 2007 were studied. Of these, 46 eyes (88%) had undergone filtering surgery earlier whereas remaining eyes underwent primary AGV implantation following failure of maximal medical therapy. The follow up ranged between 12 months to 48 months Results: Eighteen eyes (35%) had undergone phacoemulsification with AGV implantation, penetrating keratoplasty (PK) with AGV and intraocular lens (IOL) implantation in 13 eyes (25%), AGV over preexisting IOL in eight eyes (15%). AGV implantation alone was done in six (11%) eyes. Anterior chamber (AC) reconstruction with secondary IOL and AGV was performed in the remaining eyes. The mean intra ocular pressure (IOP) decreased from 36.3 ± 15.7 mm Hg to 19.6 ± 9.2 mm Hg. Complete success as per criteria was achieved in 46 eyes (88%). None of the eyes had failure to maintain IOP control following AGV. Conclusion: The AGV resulted in effective and sustained control of IOP in cases of adult refractory glaucoma in intermediate follow up. PMID:19700871

Diagnostic performance of multi-organ ultrasound with pocket-sized device in the management of acute dyspnea.

PubMed

Sforza, Alfonso; Mancusi, Costantino; Carlino, Maria Viviana; Buonauro, Agostino; Barozzi, Marco; Romano, Giuseppe; Serra, Sossio; de Simone, Giovanni

2017-06-19

The availability of ultra-miniaturized pocket ultrasound devices (PUD) adds diagnostic power to the clinical examination. Information on accuracy of ultrasound with handheld units in immediate differential diagnosis in emergency department (ED) is poor. The aim of this study is to test the usefulness and accuracy of lung ultrasound (LUS) alone or combined with ultrasound of the heart and inferior vena cava (IVC) using a PUD for the differential diagnosis of acute dyspnea (AD). We included 68 patients presenting to the ED of "Maurizio Bufalini" Hospital in Cesena (Italy) for AD. All patients underwent integrated ultrasound examination (IUE) of lung-heart-IVC, using PUD. The series was divided into patients with dyspnea of cardiac or non-cardiac origin. We used 2 × 2 contingency tables to analyze sensitivity, specificity, positive predictive value and negative predictive value of the three ultrasonic methods and their various combinations for the diagnosis of cardiogenic dyspnea (CD), comparing with the final diagnosis made by an independent emergency physician. LUS alone exhibited a good sensitivity (92.6%) and specificity (80.5%). The highest accuracy (90%) for the diagnosis of CD was obtained with the combination of LUS and one of the other two methods (heart or IVC). The IUE with PUD is a useful extension of the clinical examination, can be readily available at the bedside or in ambulance, requires few minutes and has a reliable diagnostic discriminant ability in the setting of AD.

Effect of oxybuprocaine eye drops on corneal volume and thickness measurements.

PubMed

Rosa, Nicola; De Bernardo, Maddalena; Borrelli, Maria; Filosa, Maria Luisa; Lanza, Michele

2011-05-01

To investigate the effect of oxybuprocaine eye drops on corneal volume (CV) and corneal thickness measurements. Central corneal thickness (CCT), corneal thinnest point (CTP), and CV of 78 eyes of 78 healthy volunteers were measured with Pentacam, before and 5 min after the administration of oxybuprocaine eye drops. The fellow non-anesthetized eyes were used as control. Before topical anesthesia, the mean CCT was 546.76 ± 35.3 μm, after anesthesia, it was 547.76 ± 36.56 μm (p = 0.86). In the fellow eyes, the first mean CCT was 548.82 ± 35.2 μm and the second was 547.55 ± 35.9 μm (p = 0.82). The mean CTP before anesthesia was 543.99 ± 35.23 μm, after it was 544.89 ± 36.3 μm (p = 0.88). In the fellow eyes, the first mean CTP was 544.15 ± 35.35 μm and the second was 542.81 ± 36 μm (p = 0.81). Before topical anesthesia, the mean CV was 60.55 ± 3.84 mm, after it was 60.66 ± 3.97 mm (p = 0.86). In the fellow eyes, the first mean CV was 60.93 ± 3.87 mm and the second was 60.73 ± 4 mm (p = 0.75). Oxybuprocaine eye drops do not appear to induce a significant corneal swelling and do not affect the measurements when comparing CCT measured with optical or ultrasound devices.

In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies.

PubMed

Radziemski, Leon; Makin, Inder Raj S

2016-01-01

Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10-15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5h of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasound skin tightening.

PubMed

Minkis, Kira; Alam, Murad

2014-01-01

Ultrasound skin tightening is a noninvasive, nonablative method that allows for energy deposition into the deep dermal and subcutaneous tissue while avoiding epidermal heating. Ultrasound coagulation is confined to arrays of 1-mm(3) zones that include the superficial musculoaponeurotic system and connective tissue. This technology gained approval from the Food and Drug Administration as the first energy-based skin "lifting" device, specifically for lifting lax tissue on the neck, submentum, and eyebrows. Ultrasound has the unique advantage of direct visualization of treated structures during treatment. Ultrasound is a safe and efficacious treatment for mild skin tightening and lifting. Copyright © 2014 Elsevier Inc. All rights reserved.

Design evolution enhances patient compliance for low-intensity pulsed ultrasound device usage

PubMed Central

Pounder, Neill M; Jones, John T; Tanis, Kevin J

2016-01-01

Poor patient compliance or nonadherence with prescribed treatments can have a significant unfavorable impact on medical costs and clinical outcomes. In the current study, voice-of-the-customer research was conducted to aid in the development of a next-generation low-intensity pulsed ultrasound (LIPUS) bone healing product. An opportunity to improve patient compliance reporting was identified, resulting in the incorporation into the next-generation device of a visual calendar that provides direct feedback to the patient, indicating days for which they successfully completed treatment. Further investigation was done on whether inclusion of the visual calendar improved patient adherence to the prescribed therapy (20 minutes of daily treatment) over a 6-month period. Thus, 12,984 data files were analyzed from patients prescribed either the earlier- or the next-generation LIPUS device. Over the 6-month period, overall patient compliance was 83.8% with the next-generation LIPUS device, compared with 74.2% for the previous version (p<0.0001). Incorporation of the calendar feature resulted in compliance never decreasing below 76% over the analysis period, whereas compliance with the earlier-generation product fell to 51%. A literature review on the LIPUS device shows a correlation between clinical effectiveness and compliance rates more than 70%. Incorporation of stakeholder feedback throughout the design and innovation process of a next-generation LIPUS device resulted in a measurable improvement in patient adherence, which may help to optimize clinical outcomes. PMID:27942237

Fast Conformal Thermal Ablation in the Prostate with Transurethral Multi-Sectored Ultrasound Devices and MR Guidance

NASA Astrophysics Data System (ADS)

Kinsey, Adam M.; Diederich, Chris J.; Nau, William H.; Ross, Anthony B.; Pauly, Kim Butts; Rieke, Viola; Sommer, Graham

2007-05-01

Transurethral ultrasound applicators incorporating an array of multisectored tubular transducers were evaluated in theoretical simulations and in vivo canine prostates under MR guidance as a method for fast, conformal thermal therapy of the prostate. Comprehensive simulations with a biothermal model investigated the effect on lesion creation of sector size, perfusion, treatment time, rectal cooling, prostate target dimensions, and feedback controller parameters (maximum temperature, pilot points at boundary, update times). In vivo canine prostates (n = 4) were treated with trisectored ultrasound transducers (3 mm OD) under MR temperature monitoring to contour the ablation zone (>52 C for 1-2 min) to the boundary of the prostate. Contiguous thermal lesions extended 2 cm in radius from the urethra in less than 15 min and independent sector control simultaneously allowed for conformal treatment in the angular dimension. Experiments investigated sequential translation of the transducer assembly within the catheter for tailoring heat treatments to different partitions in the prostate (base, apex) without changing the initial setup. This treatment method offered greater lesion shape control in three dimensions and slightly lengthened the overall treatment time. The MR temperature images correlated with post-treatment histology and accurately controlled the heating to the target boundary. MR-based control of transurethral ultrasound devices appeared more practical with multisectored transducers compared to rotating curvilinear and planar applicators due to less stringent requirements on spatial and temporal MR parameters. This study demonstrated the applicability of these devices in the prostate for anterior-lateral BPH treatment, and whole gland or quadrant target volumes for cancer treatment.

Prostate thermal therapy with catheter-based ultrasound devices and MR thermal monitoring

NASA Astrophysics Data System (ADS)

Diederich, Chris J.; Nau, Will H.; Kinsey, Adam; Ross, Tony; Wootton, Jeff; Juang, Titania; Butts-Pauly, Kim; Ricke, Viola; Liu, Erin H.; Chen, Jing; Bouley, Donna M.; Van den Bosch, Maurice; Sommer, Graham

2007-02-01

Four types of transurethral applicators were devised for thermal ablation of prostate combined with MR thermal monitoring: sectored tubular transducer devices with directional heating patterns; planar and curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with directional or dynamic angular control. In vivo experiments in canine prostate under MR temperature imaging were used to evaluate the heating technology and develop treatment control strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature and thermal dose in multiple slices through the target volume. Sectored tubular, planar, and curvilinear transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. Sequential rotation and modulated dwell time can conform thermal ablation to selected regions. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with directional devices can be used to effectively ablate the posterior peripheral zone of the gland while protecting the rectum. The MR derived 52 °C and lethal thermal dose contours (t 43=240 min) allowed for real-time control of the applicators and effectively defined the extent of thermal damage. Catheter-based ultrasound devices, combined with MR thermal monitoring, can produce relatively fast and precise thermal ablation of prostate, with potential for treatment of cancer or BPH.

Power Doppler ultrasonography and synovitis: correlating ultrasound imaging with histopathological findings and evaluating the performance of ultrasound equipments.

PubMed

Koski, J M; Saarakkala, S; Helle, M; Hakulinen, U; Heikkinen, J O; Hermunen, H

2006-12-01

To examine the validity of power Doppler ultrasound imaging to identify synovitis, using histopathology as gold standard, and to assess the performance of ultrasound equipments. 44 synovial sites in small and large joints, bursae and tendon sheaths were depicted with ultrasound. A synovial biopsy was performed on the site depicted and a synovial sample was taken for histopathological evaluation. The performance of three ultrasound devices was tested using flow phantoms. A positive Doppler signal was detected in 29 of 35 (83%) of the patients with active histological inflammation. In eight additional samples, histological examination showed other pathological synovial findings and a Doppler signal was detected in five of them. No significant correlation was found between the amount of Doppler signal and histological synovitis score (r = 0.239, p = NS). The amount of subsynovial infiltration of polymorphonuclear leucocytes and surface fibrin correlated significantly with the amount of power Doppler signal: r = 0.397 (p<0.01) and 0.328 (p<0.05), respectively. The ultrasound devices differed in showing the smallest detectable flow. A negative Doppler signal does not exclude the possibility of synovitis. A positive Doppler signal in the synovium is an indicator of an active synovial inflammation in patients. A Doppler signal does not correlate with the extent of the inflammation and it can also be seen in other synovial reactions. It is important that the quality measurements of ultrasound devices are reported, because the results should be evaluated against the quality of the device used.

Beef quality parameters estimation using ultrasound and color images

PubMed Central

2015-01-01

Background Beef quality measurement is a complex task with high economic impact. There is high interest in obtaining an automatic quality parameters estimation in live cattle or post mortem. In this paper we set out to obtain beef quality estimates from the analysis of ultrasound (in vivo) and color images (post mortem), with the measurement of various parameters related to tenderness and amount of meat: rib eye area, percentage of intramuscular fat and backfat thickness or subcutaneous fat. Proposal An algorithm based on curve evolution is implemented to calculate the rib eye area. The backfat thickness is estimated from the profile of distances between two curves that limit the steak and the rib eye, previously detected. A model base in Support Vector Regression (SVR) is trained to estimate the intramuscular fat percentage. A series of features extracted on a region of interest, previously detected in both ultrasound and color images, were proposed. In all cases, a complete evaluation was performed with different databases including: color and ultrasound images acquired by a beef industry expert, intramuscular fat estimation obtained by an expert using a commercial software, and chemical analysis. Conclusions The proposed algorithms show good results to calculate the rib eye area and the backfat thickness measure and profile. They are also promising in predicting the percentage of intramuscular fat. PMID:25734452

Modeling of endoluminal and interstitial ultrasound hyperthermia and thermal ablation: applications to device design, feedback control, and treatment planning

PubMed Central

Prakash, Punit; Salgaonkar, Vasant A.; Diederich, Chris J.

2014-01-01

Endoluminal and catheter-based ultrasound applicators are currently under development and are in clinical use for minimally invasive hyperthermia and thermal ablation of various tissue targets. Computational models play a critical role in in device design and optimization, assessment of therapeutic feasibility and safety, devising treatment monitoring and feedback control strategies, and performing patient-specific treatment planning with this technology. The critical aspects of theoretical modeling, applied specifically to endoluminal and interstitial ultrasound thermotherapy, are reviewed. Principles and practical techniques for modeling acoustic energy deposition, bioheat transfer, thermal tissue damage, and dynamic changes in the physical and physiological state of tissue are reviewed. The integration of these models and applications of simulation techniques in identification of device design parameters, development of real time feedback-control platforms, assessing the quality and safety of treatment delivery strategies, and optimization of inverse treatment plans are presented. PMID:23738697

Measurements of donor endothelial keratoplasty lenticules prepared from fresh donated whole eyes by using ultrasound and optical coherence tomography.

PubMed

Kanavi, Mozhgan Rezaei; Nemati, Farzan; Chamani, Tahereh; Kheiri, Bahar; Javadi, Mohammad Ali

2017-03-01

This study was conducted to analyze the profile and thickness of endothelial keratoplasty lenticules prepared from fresh donated whole eyes with Visante optical coherence tomography (V-OCT) compared to measurements obtained from ultrasound pachymetry (USP) at the Central Eye Bank of Iran. Microkeratome-assisted precut corneas were prepared for Descemet stripping automated endothelial keratoplasty by using standard eye bank protocol. Central posterior lenticule thickness (CPLT) on fresh whole eye, before excising corneoscleral disc and transferring to Optisol-GS, was measured by USP. V-OCT was used to measure central, paracentral, and midperipheral thicknesses of lenticules after transferring the tissue to Optisol-GS. Chi Square and Bonferroni tests were respectively used to uncover the differences between the USP and V-OCT measurements and also the thickness profile of lenticules. Postoperative reports for the entire transplanted lenticules were recorded. Accordingly, on evaluation of 312 enrolled precut corneas, CPLT measurements by V-OCT versus USP were statistically different (mean: 136 µm vs 165 µm, respectively; P = 0.008). Thickness profile of the posterior lenticules revealed increased thickness from the central to the peripheral parts of the cornea (mean increase of 16 µm at the pericentral and 64.2 µm at the peripheral locations, respectively); however, the increase in the thickness was relatively symmetrical. Postoperative reports of transplanted lenticules were unremarkable, since there were no posterior flap detachments. In essence, V-OCT measurements of microkeratome-assisted precut lenticules prepared from fresh donated whole eyes averaged 29 μm thinner than USP measurements and revealed a significant but symmetric increase of thickness towards the peripheral parts of the corneas. However, the variation in the thickness profile did not affect the attachment or the clarity of transplanted precut lenticlues.

A real-time device for converting Doppler ultrasound audio signals into fluid flow velocity

PubMed Central

Hogeman, Cynthia S.; Koch, Dennis W.; Krishnan, Anandi; Momen, Afsana; Leuenberger, Urs A.

2010-01-01

A Doppler signal converter has been developed to facilitate cardiovascular and exercise physiology research. This device directly converts audio signals from a clinical Doppler ultrasound imaging system into a real-time analog signal that accurately represents blood flow velocity and is easily recorded by any standard data acquisition system. This real-time flow velocity signal, when simultaneously recorded with other physiological signals of interest, permits the observation of transient flow response to experimental interventions in a manner not possible when using standard Doppler imaging devices. This converted flow velocity signal also permits a more robust and less subjective analysis of data in a fraction of the time required by previous analytic methods. This signal converter provides this capability inexpensively and requires no modification of either the imaging or data acquisition system. PMID:20173048

Wireless communication of real-time ultrasound data and control

NASA Astrophysics Data System (ADS)

Tobias, Richard J.

2015-03-01

The Internet of Things (IoT) is expected to grow to 26 billion connected devices by 2020, plus the PC, smart phone, and tablet segment that includes mobile Health (mHealth) connected devices is projected to account for another 7.3 billion units by 2020. This paper explores some of the real-time constraints on the data-flow and control of a wireless connected ultrasound machine. The paper will define an ultrasound server and the capabilities necessary for real-time use of the device. The concept of an ultrasound server wirelessly (or over any network) connected to multiple lightweight clients on devices like an iPad, iPhone, or Android-based tablet, smartphone and other network-attached displays (i.e., Google Glass) is explored. Latency in the ultrasound data stream is one of the key areas to measure and to focus on keeping as small as possible (<30ms) so that the ultrasound operator can see what is at the probe at that moment, instead of where the probe was a short period earlier. By keeping the latency less than 30ms, the operator will feel like the data he sees on the wireless connected devices is running in real-time with the operator. The second parameter is the management of bandwidth. At minimum we need to be able to see 20 frames-per- second. It is possible to achieve ultrasound in triplex mode at >20 frames-per-second on a properly configured wireless network. The ultrasound server needs to be designed to accept multiple ultrasound data clients and multiple control clients. A description of the server and some of its key features will be described.

Simulation Study of an Ultrasound Retinal Prosthesis With a Novel Contact-Lens Array for Noninvasive Retinal Stimulation.

PubMed

Gao, Mengdi; Yu, Yanyan; Zhao, Huixia; Li, Guofeng; Jiang, Hongyang; Wang, Congzhi; Cai, Feiyan; Chan, Leanne Lai-Hang; Chiu, Bernard; Qian, Wei; Qiu, Weibao; Zheng, Hairong

2017-09-01

Millions of people around the world suffer from varying degrees of vision loss (including complete blindness) because of retinal degenerative diseases. Artificial retinal prosthesis, which is usually based on electrical neurostimulation, is the most advanced technology for different types of retinal degeneration. However, this technology involves placing a device into the eyeball, and such a highly invasive procedure is inevitably highly risk and expensive. Ultrasound has been demonstrated to be a promising technology for noninvasive neurostimulation, making it possible to stimulate the retina and induce action potentials similar to those elicited by light stimulation. However, the technology of ultrasound retinal stimulation still requires considerable developments before it could be applied clinically. This paper proposes a novel contact-lens array transducer for use in an ultrasound retinal prosthesis (USRP). The transducer was designed in the shape of a contact lens so as to facilitate acoustic coupling with the eye liquid. The key parameters of the ultrasound transducer were simulated, and results are presented that indicate the achievement of 2-D pattern generation and that the proposed contact-lens array is suitable for multiple-focus neurostimulation, and can be used in a USRP.

Portable bladder ultrasound: an evidence-based analysis.

PubMed

2006-01-01

retention, requiring intermittent catheterization, whereas a PVR urine volume of 100 mL to 150 mL or less is generally considered an acceptable result of bladder training. Urinary retention has been associated with poor outcomes including UTI, bladder overdistension, and higher hospital mortality rates. The standard method of determining PVR urine volumes is intermittent catheterization, which is associated with increased risk of UTI, urethral trauma and discomfort. Portable bladder ultrasound products are transportable ultrasound devices that use automated technology to register bladder volume digitally, including PVR volume, and provide three-dimensional images of the bladder. The main clinical use of portable bladder ultrasound is as a diagnostic aid. Health care professionals (primarily nurses) administer the device to measure PVR volume and prevent unnecessary catheterization. An adjunctive use of the bladder ultrasound device is to visualize the placement and removal of catheters. Also, portable bladder ultrasound products may improve the diagnosis and differentiation of urological problems and their management and treatment, including the establishment of voiding schedules, study of bladder biofeedback, fewer UTIs, and monitoring of potential urinary incontinence after surgery or trauma. To determine the effectiveness and clinical utility of portable bladder ultrasound as reported in the published literature, the Medical Advisory Secretariat used its standard search strategy to retrieve international health technology assessments and English-language journal articles from selected databases. Nonsystematic reviews, nonhuman studies, case reports, letters, editorials, and comments were excluded. Of the 4 included studies that examined the clinical utility of portable bladder ultrasound in the elderly population, all found the device to be acceptable. One study reported that the device underestimated catheterized bladder volume In patients with urology problems, 2 of

Hot topics in biomedical ultrasound: ultrasound therapy and its integration with ultrasonic imaging

NASA Astrophysics Data System (ADS)

Everbach, E. Carr

2005-09-01

Since the development of biomedical ultrasound imaging from sonar after WWII, there has been a clear divide between ultrasonic imaging and ultrasound therapy. While imaging techniques are designed to cause as little change as possible in the tissues through which ultrasound propagates, ultrasound therapy typically relies upon heating or acoustic cavitation to produce a desirable therapeutic effect. Concerns over the increasingly high acoustic outputs of diagnostic ultrasound scanners prompted the adoption of the Mechanical Index (MI) and Thermal Index (TI) in the early 1990s. Therapeutic applications of ultrasound, meanwhile, have evolved from deep tissue heating in sports medicine to include targeted drug delivery, tumor and plaque ablation, cauterization via high intensity focused ultrasound (HIFU), and accelerated dissolution of blood clots. The integration of ultrasonic imaging and therapy in one device is just beginning, but the promise of improved patient outcomes is balanced by regulatory and practical impediments.

Intraocular pressure control of a novel glaucoma drainage device - in vitro and in vivo studies

PubMed Central

Cui, Li-Jun; Li, Di-Chen; Liu, Jian; Zhang, Lei; Xing, Yao

2017-01-01

AIM To evaluate the intraocular pressure (IOP) control of an artificial trabeculum drainage system (ATDS), a newly designed glaucoma drainage device, and postoperative complications in normal rabbit eyes. METHODS Pressure drops in air and fluid of 30 ATDS were measured after being connected to a closed manometric system. Twenty of them were then chosen and implanted randomly into the eyes of 20 rabbits. Postoperative slit-lamp, gonioscopic examination and IOP measurements were recorded periodically. Ultrasound biomicroscopy and B-scan ultrasonography were also used to observe the complications. Eyes were enucleated on day 60. RESULTS Pressure drops of 4.6-9.4 mm Hg were obtained at physiological aqueous flow rates in the tests in vitro. The average postoperative IOP of the experimental eyes (11.6-12.8 mm Hg) was lower than the controls significantly (P<0.05) at each time point. Complications of hemorrhage (n=1), cellulosic exudation (two cases) and local iris congestion (two cases) were observed. The lumina of the devices were devoid of obstructions in all specimens examined and a thin fibrous capsule was found around the endplate. CONCLUSION ATDS reduce IOP effectively. However, further studies on the structure are needed to reduce complications. PMID:28944192

The utility of ultrasound in patients with melanoma.

PubMed

Uren, Roger F; Sanki, Amira; Thompson, John F

2007-11-01

The highest quality gray-scale ultrasound images are obtained with high-frequency transducers; however, such high frequencies do not penetrate more than a few centimeters into body tissue. Fortunately, in patients with melanoma, the structures of interest are close to the skin surface, making them ideal targets for examination with high-resolution ultrasound. These include primary cutaneous melanomas, uveal melanomas and the regional lymph nodes draining the skin that lie in the axilla, groin, neck and other locations. Although ultrasound study of primary melanomas arising in the skin and eye has provided some insights, a major role for ultrasound has evolved recently, to provide early detection of metastatic melanoma in regional lymph nodes. Ultrasound is clearly superior to clinical palpation of the nodes during follow-up and, when combined with guided fine-needle biopsy, allows the earliest possible surgical intervention for regional nodal metastases. In the future the use of ultrasound contrast agents may improve the sensitivity of ultrasound in the detection of very small metastatic deposits.

Ultrasound physics and instrumentation for pathologists.

PubMed

Lieu, David

2010-10-01

Interest in pathologist-performed ultrasound-guided fine-needle aspiration is increasing. Educational courses discuss clinical ultrasound and biopsy techniques but not ultrasound physics and instrumentation. To review modern ultrasound physics and instrumentation to help pathologists understand the basis of modern ultrasound. A review of recent literature and textbooks was performed. Ultrasound physics and instrumentation are the foundations of clinical ultrasound. The key physical principle is the piezoelectric effect. When stimulated by an electric current, certain crystals vibrate and produce ultrasound. A hand-held transducer converts electricity into ultrasound, transmits it into tissue, and listens for reflected ultrasound to return. The returning echoes are converted into electrical signals and used to create a 2-dimensional gray-scale image. Scanning at a high frequency improves axial resolution but has low tissue penetration. Electronic focusing moves the long-axis focus to depth of the object of interest and improves lateral resolution. The short-axis focus in 1-dimensional transducers is fixed, which results in poor elevational resolution away from the focal zone. Using multiple foci improves lateral resolution but degrades temporal resolution. The sonographer can adjust the dynamic range to change contrast and bring out subtle masses. Contrast resolution is limited by processing speed, monitor resolution, and gray-scale perception of the human eye. Ultrasound is an evolving field. New technologies include miniaturization, spatial compound imaging, tissue harmonics, and multidimensional transducers. Clinical cytopathologists who understand ultrasound physics, instrumentation, and clinical ultrasound are ready for the challenges of cytopathologist-performed ultrasound-guided fine-needle aspiration and core-needle biopsy in the 21st century.

Rabbits' eye globe sonographic biometry.

PubMed

Toni, Maria Carolina; Meirelles, Adriana Érica Wilkes Burton; Gava, Fábio Nelson; Camacho, Aparecido Antônio; Laus, José Luiz; Canola, Júlio Carlos

2010-11-01

To measure intraocular structures in New Zealand White breed rabbits (Oryctolagus cuniculus Linnaeus, 1758) using A-mode and B-mode ultrasound with a 20 MHz transducer. In this study, the eyes of 15 rabbits were evaluated for determination of intraocular measurements using an ophthalmic ultrasound unit able to operate in both A and B-modes. The distances from the cornea to the anterior capsule of the lens (D1), from the anterior capsule of the lens to the posterior capsule of the lens (D2), from the posterior capsule of the lens to the retina (D3) and the complete length of the eye, which corresponds to the distance from the cornea to the retina (D4) were taken. The mean values obtained were 2.70 mm (± 0.22 mm) for D1, 7.32 mm (± 0.40 mm) for D2, 7.10 mm (± 0.45 mm) for D3 and 17.12 mm (± 0.41 mm) for D4. Statistical analyses using the Student's t-test showed that there were no differences between the eyes. The study was feasible without the need of pharmacological restraint and yielded normal mean values for ocular sonographic biometry in rabbits. © 2010 American College of Veterinary Ophthalmologists.

In vivo retinal imaging for fixational eye motion detection using a high-speed digital micromirror device (DMD)-based ophthalmoscope.

PubMed

Vienola, Kari V; Damodaran, Mathi; Braaf, Boy; Vermeer, Koenraad A; de Boer, Johannes F

2018-02-01

Retinal motion detection with an accuracy of 0.77 arcmin corresponding to 3.7 µm on the retina is demonstrated with a novel digital micromirror device based ophthalmoscope. By generating a confocal image as a reference, eye motion could be measured from consecutively measured subsampled frames. The subsampled frames provide 7.7 millisecond snapshots of the retina without motion artifacts between the image points of the subsampled frame, distributed over the full field of view. An ophthalmoscope pattern projection speed of 130 Hz enabled a motion detection bandwidth of 65 Hz. A model eye with a scanning mirror was built to test the performance of the motion detection algorithm. Furthermore, an in vivo motion trace was obtained from a healthy volunteer. The obtained eye motion trace clearly shows the three main types of fixational eye movements. Lastly, the obtained eye motion trace was used to correct for the eye motion in consecutively obtained subsampled frames to produce an averaged confocal image correct for motion artefacts.

In vivo retinal imaging for fixational eye motion detection using a high-speed digital micromirror device (DMD)-based ophthalmoscope

PubMed Central

Vienola, Kari V.; Damodaran, Mathi; Braaf, Boy; Vermeer, Koenraad A.; de Boer, Johannes F.

2018-01-01

Retinal motion detection with an accuracy of 0.77 arcmin corresponding to 3.7 µm on the retina is demonstrated with a novel digital micromirror device based ophthalmoscope. By generating a confocal image as a reference, eye motion could be measured from consecutively measured subsampled frames. The subsampled frames provide 7.7 millisecond snapshots of the retina without motion artifacts between the image points of the subsampled frame, distributed over the full field of view. An ophthalmoscope pattern projection speed of 130 Hz enabled a motion detection bandwidth of 65 Hz. A model eye with a scanning mirror was built to test the performance of the motion detection algorithm. Furthermore, an in vivo motion trace was obtained from a healthy volunteer. The obtained eye motion trace clearly shows the three main types of fixational eye movements. Lastly, the obtained eye motion trace was used to correct for the eye motion in consecutively obtained subsampled frames to produce an averaged confocal image correct for motion artefacts. PMID:29552396

Corneal seal device

NASA Technical Reports Server (NTRS)

Baehr, E. F. (Inventor)

1977-01-01

A corneal seal device is provided which, when placed in an incision in the eye, permits the insertion of a surgical tool or instrument through the device into the eye. The device includes a seal chamber which opens into a tube which is adapted to be sutured to the eye and serves as an entry passage for a tool. A sealable aperture in the chamber permits passage of the tool through the chamber into the tube and hence into the eye. The chamber includes inlet ports adapted to be connected to a regulated source of irrigation fluid which provides a safe intraocular pressure.

Effect of ultrasound radiation force on the choroid.

PubMed

Silverman, Ronald H; Urs, Raksha; Lloyd, Harriet O

2013-01-10

While visualization of the retina and choroid has made great progress, functional imaging techniques have been lacking. Our aim was to utilize acoustic radiation force impulse (ARFI) response to probe functional properties of these tissues. A single element 18-MHz ultrasound transducer was focused upon the retina of the rabbit eye. The procedure was performed with the eye proptosed and with the eye seated normally in the orbit. The transducer was excited to emit ARFI over a 10-ms period with a 25% duty cycle. Phase resolved pulse/echo data were acquired before, during, and following ARFI. In the proptosed eye, ARFI exposure produced tissue displacements ranging from 0 to 10 μm, and an immediate increase in choroidal echo amplitude to over 6 dB, decaying to baseline after about 1 second. In the normally seated eye, ultrasound phase shifts consistent with flow were observed in the choroid, but enhanced backscatter following ARFI rarely occurred. ARFI-induced displacements of about 10 μm were observed at the choroidal margins. Larger displacements occurred within the choroid and in orbital tissues. We hypothesize that elevated intraocular pressure occurring during proptosis induced choroidal ischemia and that acoustic radiation force produced a transient local decompression and reperfusion. With the eye normally seated, choroidal flow was observed and little alteration in backscatter resulted from exposure. Clinical application of this technique may provide new insights into diseases characterized by altered choroidal hemodynamics, including maculopathies, diabetic retinopathy, and glaucoma.

Impedance-controlled ultrasound probe

NASA Astrophysics Data System (ADS)

Gilbertson, Matthew W.; Anthony, Brian W.

2011-03-01

An actuated hand-held impedance-controlled ultrasound probe has been developed. The controller maintains a prescribed contact state (force and velocity) between the probe and a patient's body. The device will enhance the diagnostic capability of free-hand elastography and swept-force compound imaging, and also make it easier for a technician to acquire repeatable (i.e. directly comparable) images over time. The mechanical system consists of an ultrasound probe, ball-screw-driven linear actuator, and a force/torque sensor. The feedback controller commands the motor to rotate the ball-screw to translate the ultrasound probe in order to maintain a desired contact force. It was found that users of the device, with the control system engaged, maintain a constant contact force with 15 times less variation than without the controller engaged. The system was used to determine the elastic properties of soft tissue.

Objective straylight assessment of the human eye with a novel device

NASA Astrophysics Data System (ADS)

Schramm, Stefan; Schikowski, Patrick; Lerm, Elena; Kaeding, André; Klemm, Matthias; Haueisen, Jens; Baumgarten, Daniel

2016-03-01

Forward scattered light from the anterior segment of the human eye can be measured by Shack-Hartmann (SH) wavefront aberrometers with limited visual angle. We propose a novel Point Spread Function (PSF) reconstruction algorithm based on SH measurements with a novel measurement devise to overcome these limitations. In our optical setup, we use a Digital Mirror Device as variable field stop, which is conventionally a pinhole suppressing scatter and reflections. Images with 21 different stop diameters were captured and from each image the average subaperture image intensity and the average intensity of the pupil were computed. The 21 intensities represent integral values of the PSF which is consequently reconstructed by derivation with respect to the visual angle. A generalized form of the Stiles-Holladay-approximation is fitted to the PSF resulting in a stray light parameter Log(IS). Additionaly the transmission loss of eye is computed. For the proof of principle, a study on 13 healthy young volunteers was carried out. Scatter filters were positioned in front of the volunteer's eye during C-Quant and scatter measurements to generate straylight emulating scatter in the lens. The straylight parameter is compared to the C-Quant measurement parameter Log(ISC) and scatter density of the filters SDF with a partial correlation. Log(IS) shows significant correlation with the SDF and Log(ISC). The correlation is more prominent between Log(IS) combined with the transmission loss and the SDF and Log(ISC). Our novel measurement and reconstruction technique allow for objective stray light analysis of visual angles up to 4 degrees.

Novel ultrasound method to reposition kidney stones

PubMed Central

Shah, Anup; Owen, Neil R.; Lu, Wei; Cunitz, Bryan W.; Kaczkowski, Peter J.; Harper, Jonathan D.; Bailey, Michael R.; Crum, Lawrence A.

2011-01-01

The success of surgical management of lower pole stones is principally dependent on stone fragmentation and residual stone clearance. Choice of surgical method depends on stone size, yet all methods are subject to post-surgical complications resulting from residual stone fragments. Here we present a novel method and device to reposition kidney stones using ultrasound radiation force delivered by focused ultrasound and guided by ultrasound imaging. The device couples a commercial imaging array with a focused annular array transducer. Feasibility of repositioning stones was investigated by implanting artificial and human stones into a kidney-mimicking phantom that simulated a lower pole and collecting system. During experiment, stones were located by ultrasound imaging and repositioned by delivering short bursts of focused ultrasound. Stone motion was concurrently monitored by fluoroscopy, ultrasound imaging, and video photography, from which displacement and velocity were estimated. Stones were seen to move immediately after delivering focused ultrasound and successfully repositioned from the lower pole to the collecting system. Estimated velocities were on the order of 1 cm/s. This in vitro study demonstrates a promising modality to facilitate spontaneous clearance of kidney stones and increased clearance of residual stone fragments after surgical management. PMID:20967437

Eye Safety. Mississippi Industrial Arts.

ERIC Educational Resources Information Center

Mississippi State Dept. of Education, Jackson. Div. of Vocational and Technical Education.

This manual is designed to help industrial arts teachers eliminate student eye injuries within industrial arts programs. Presented first is Mississippi eye safety law. Following a discussion of eye protection equipment, illustrations of eye protection devices are provided. Guidelines are set forth for selecting shade numbers for welding filters.…

[Electronic Device for Retinal and Iris Imaging].

PubMed

Drahanský, M; Kolář, R; Mňuk, T

This paper describes design and construction of a new device for automatic capturing of eye retina and iris. This device has two possible ways of utilization - either for biometric purposes (persons recognition on the base of their eye characteristics) or for medical purposes as supporting diagnostic device. eye retina, eye iris, device, acquisition, image.

Usefulness of optic nerve ultrasound to predict clinical progression in multiple sclerosis.

PubMed

Pérez Sánchez, S; Eichau Madueño, S; Rus Hidalgo, M; Domínguez Mayoral, A M; Vilches-Arenas, A; Navarro Mascarell, G; Izquierdo, G

2018-03-21

Progressive neuronal and axonal loss are considered the main causes of disability in patients with multiple sclerosis (MS). The disease frequently involves the visual system; the accessibility of the system for several functional and structural tests has made it a model for the in vivo study of MS pathogenesis. Orbital ultrasound is a non-invasive technique that enables various structures of the orbit, including the optic nerve, to be evaluated in real time. We conducted an observational, ambispective study of MS patients. Disease progression data were collected. Orbital ultrasound was performed on all patients, with power set according to the 'as low as reasonably achievable' (ALARA) principle. Optical coherence tomography (OCT) data were also collected for those patients who underwent the procedure. Statistical analysis was conducted using SPSS version 22.0. Disease progression was significantly correlated with ultrasound findings (P=.041 for the right eye and P=.037 for the left eye) and with Expanded Disability Status Scale (EDSS) score at the end of the follow-up period (P=.07 for the right eye and P=.043 for the left eye). No statistically significant differences were found with relation to relapses or other clinical variables. Ultrasound measurement of optic nerve diameter constitutes a useful, predictive factor for the evaluation of patients with MS. Smaller diameters are associated with poor clinical progression and greater disability (measured by EDSS). Copyright © 2018 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Focused ultrasound thermal therapy system with ultrasound image guidance and temperature measurement feedback.

PubMed

Lin, Kao-Han; Young, Sun-Yi; Hsu, Ming-Chuan; Chan, Hsu; Chen, Yung-Yaw; Lin, Win-Li

2008-01-01

In this study, we developed a focused ultrasound (FUS) thermal therapy system with ultrasound image guidance and thermocouple temperature measurement feedback. Hydraulic position devices and computer-controlled servo motors were used to move the FUS transducer to the desired location with the measurement of actual movement by linear scale. The entire system integrated automatic position devices, FUS transducer, power amplifier, ultrasound image system, and thermocouple temperature measurement into a graphical user interface. For the treatment procedure, a thermocouple was implanted into a targeted treatment region in a tissue-mimicking phantom under ultrasound image guidance, and then the acoustic interference pattern formed by image ultrasound beam and low-power FUS beam was employed as image guidance to move the FUS transducer to have its focal zone coincident with the thermocouple tip. The thermocouple temperature rise was used to determine the sonication duration for a suitable thermal lesion as a high power was turned on and ultrasound image was used to capture the thermal lesion formation. For a multiple lesion formation, the FUS transducer was moved under the acoustic interference guidance to a new location and then it sonicated with the same power level and duration. This system was evaluated and the results showed that it could perform two-dimensional motion control to do a two-dimensional thermal therapy with a small localization error 0.5 mm. Through the user interface, the FUS transducer could be moved to heat the target region with the guidance of ultrasound image and acoustic interference pattern. The preliminary phantom experimental results demonstrated that the system could achieve the desired treatment plan satisfactorily.

Doppler Ultrasound: What Is It Used for?

MedlinePlus

... During a Doppler ultrasound, a technician trained in ultrasound imaging (sonographer) presses a small hand-held device (transducer), ... neurologic-disorders/neurologic-tests-and-procedures/other-neurologic-imaging-studies. Accessed Oct. 18, 2016. ... . Mayo Clinic Footer Legal ...

Application of high intensity focused ultrasound for treatment of open-angle glaucoma in Indian patients.

PubMed

Deb-Joardar, Nilanjana; Reddy, Kasu Prasad

2018-04-01

The aim of this study is to assess the efficacy of ultrasound cycloplasty (UCP) in Indian patients with open angle glaucoma (OAG). A prospective interventional study was designed to treat 73 eyes of 73 patients with OAG with the EyeOP1 device equipped with six miniaturized cylindrical piezoelectric transducers. Two treatment protocols of ultrasound delivery depending on exposure time (8 s and 10 s of shot per transducer) were used. Complete ophthalmic examination, ocular biometry and anterior segment optical coherence tomography were performed preoperatively and patients were followed up at day 1, day 7 and months 1, 2, 3, 6, and 12. The primary outcome measure was "successful" intraocular pressure (IOP) control defined as IOP reduction ≥20% from baseline and IOP value >5 mm Hg at the last follow-up visit. Secondary outcomes were the occurrence of complications and mean IOP during the follow-up period. In all patients, the mean IOP reduced from 23.5 ± 3.0 mmHg before treatment to 15.7 ± 5.4 mmHg at 12 months (P < 0.05). Successful IOP control after a single procedure was 78.3% (79% and 78% in the 8 s and 10 s groups, respectively) at 12 months. Overall, the mean IOP reduction achieved in responding patients was 41% (standard deviation = 12%). Notwithstanding minor side effects such as transient pain, anterior chamber reaction, and refractive error changes, no major intraoperative or postoperative complications (severe hypotony or phthisis) were observed during the follow-up. Our short-term results reveal that UCP is a simple, safe, and noninvasive procedure which enables to significantly reduce the IOP in patients with OAG. The study results in Indian eyes corroborate findings in earlier studies on Caucasian eyes.

Ultrasound internal tattooing.

PubMed

Couture, Olivier; Faivre, Magalie; Pannacci, Nicolas; Babataheri, Avin; Servois, Vincent; Tabeling, Patrick; Tanter, Mickael

2011-02-01

The ability of remotely tagging tissues in a controlled and three-dimensional manner during preoperative imaging could greatly help surgeons to identify targets for resection. The authors' objective is to selectively and noninvasively deposit markers under image guidance for such internal tattooing. This study describes the production of new ultrasound-inducible droplets carrying large payloads of fluorescent markers and the in vivo proof of concept of their remote and controlled deposition via focused ultrasound. The droplets are monodispersed multiple emulsions produced in a microfluidic system, consisting of aqueous fluorescein in perfluorocarbon in water. Their conversion (either by vaporization or cavitation) is performed remotely using a clinical ultrasonic imaging probe. When submitted to 5 MHz imaging pulses, the droplets vaporize in vitro at 1.4 MPa peak-negative pressure and eject their content. After several seconds, a brightly fluorescent spot (0.5 mm diameter) is observed at the focus of the transducer. Experiments in the chorioallantoique membrane of chicken eggs and chicken embryo demonstrate that the spot is stable and is easily seen by naked eye. These ultrasound-inducible multiple emulsions could be used to deliver large amounts of contrast agents, chemotherapy, and genetic materials in vivo using a conventional ultrasound scanner.

A comparison of 10 MHz and 20 MHz ultrasound probes in imaging the eye and orbit.

PubMed

Hewick, S A; Fairhead, A C; Culy, J C; Atta, H R

2004-04-01

/aims: B-scan ultrasonography is an invaluable, versatile, non-invasive tool in ophthalmology. Recently, a "high frequency" contact 20 MHz probe has been introduced. B-scanning ultrasonography of orbital and ocular structures was performed with both a 10 MHz and the new 20 MHz probe, to evaluate what information was best obtained from each probe, and provide recommendations for the use of each. Patients were selected from routine ultrasound clinics at Aberdeen Royal Infirmary between 1 January 2002 and 1 August 2002. The vitreous, retina, choroid, sclera and, in the orbit, the extraocular muscles, optic nerve, and orbital fat were assessed with both the 10 MHz and 20 MHz probes. In the laboratory, using a "point target," the characteristics of the ultrasound beam at different distances from the probe were also assessed. The point target showed that focus was deeper and that the lateral, and to a lesser degree the axial, resolution are sharper with the 20 MHz probe, compared with the 10 MHz probe. In patients' eyes, highly reflective structures are seen at higher resolution with the 20 MHz probe. Imaging of lower intensity reflectors such as the vitreous and particles within it are seen better with the 10 MHz probe. Increased tissue attenuation was evident with the 20 MHz probe. The 20 MHz probe has a superior resolution and can be used to better detect details at the posterior pole and in the orbit. The 10 MHz probe can be used to examine low intensity scatterers, such as the vitreous humour, that cannot be seen using a higher frequency probe.

A scanned focused ultrasound device for hyperthermia: numerical simulation and prototype implementation

NASA Astrophysics Data System (ADS)

Meaney, Paul M.; Raynolds, Timothy; Geimer, Shireen D.; Potwin, Lincoln; Paulsen, Keith D.

2004-07-01

We are developing a scanned focused ultrasound system for hyperthermia treatment of breast cancer. Focused ultrasound has significant potential as a therapy delivery device because it can focus sufficient heating energy below the skin surface with minimal damage to intervening tissue. However, as a practical therapy system, the focal zone is generally quite small and requires either electronic (in the case of a phased array system) or mechanical steering (for a fixed bowl transducer) to cover a therapeutically useful area. We have devised a simple automated steering system consisting of a focused bowl transducer supported by three vertically movable rods which are connected to computer controlled linear actuators. This scheme is particularly attractive for breast cancer hyperthermia where the support rods can be fed through the base of a liquid coupling tank to treat tumors within the breast while coupled to our noninvasive microwave thermal imaging system. A MATLAB routine has been developed for controlling the rod motion such that the beam focal point scans a horizontal spiral and the subsequent heating zone is cylindrical. In coordination with this effort, a 3D finite element thermal model has been developed to evaluate the temperature distributions from the scanned focused heating. In this way, scanning protocols can be optimized to deliver the most uniform temperature rise to the desired location.

Novel shadowless imaging for eyes-like diagnosis in vivo

NASA Astrophysics Data System (ADS)

Xue, Ning; Jiang, Kai; Li, Qi; Zhang, Lili; Ma, Li; Huang, Guoliang

2016-10-01

Eyes-like diagnosis was a traditional Chinese medicine method for many diseases, such as chronic gastritis, diabetes, hypertension etc. There was a close relationship between viscera and eyes-like. White-Eye was divided into fourteen sections, which corresponded to different viscera, so eyes-like was the reflection of status of viscera, in another words, it was an epitome of viscera health condition. In this paper, we developed a novel shadowless imaging technology and system for eyes-like diagnosis in vivo, which consisted of an optical shadowless imaging device for capturing and saving images of patients' eyes-like, and a computer linked to the device for image processing. A character matching algorithm was developed to extract the character of white-eye in corresponding sections of eyes-like images taken by the optical shadowless imaging device, according to the character of eyes-like, whether there were viscera diseases could be learned. A series of assays were carried out, and the results verified the feasibility of eyes-like diagnosis technique.

Relationship Between Eye Movement and Cognitive Information Acquisition Utilizing an Unobtrusive Eye Movement Monitoring Device.

ERIC Educational Resources Information Center

Nesbit, Larry L.

A research study was designed to test the relationship between the number of eye fixations and amount of learning as determined by a criterion referenced posttest. The study sought to answer the following questions: (1) Are differences in eye movement indices related to the posttest score? (2) Do differences in eye movement indices of subjects…

Comparison of Central Corneal Thickness Measurements Obtained by RTVue OCT, Lenstar, Sirius Topography, and Ultrasound Pachymetry in Healthy Subjects.

PubMed

Şimşek, Ali; Bilak, Şemsettin; Güler, Mete; Çapkin, Musa; Bilgin, Burak; Reyhan, Ali Hakim

2016-01-01

To compare central corneal thickness (CCT) measurement results obtained by RTVue OCT, Lenstar, Sirius topography, and ultrasound pachymetry (UP) (OcuScan RxP Ophthalmic Ultrasound System, Alcon Laboratories) in healthy subjects. 256 eyes of 128 healthy subjects were included in the study. CCT measurements were obtained from the eyes for each subject using the UP, Lenstar, Sirius topography, and RTVue OCT instruments. Ultrasound pachymetry measurements were performed after the eyes were anesthetized with one drop of 0.5% proparacaine hydrochloride and were performed at the same day after 15 minutes after previous measurements. Of 128 participants, 84 were male and 44 were female with a mean age of 33.15 ± 12.95 years (ranging from 18 to 75 years). The mean CCTs for UP, Lenstar, Sirius topography, and RTVue OCT were 535.60 ± 35.15 (440,00-668,00); 532.63 ± 34.44 (449,00-650,00); 526.05 ± 36.45 (314,00-640,00); 525.89 ± 33.21 (437,00-646,00) µm, respectively. The mean CCT measurements were statistically different among the three groups (p = 0.002). CCT measurements obtained using RTVue-OCT were significantly thinner than those obtained using UP (p = 0.009). Sirius CCT measurements were also thinner than UP (p = 0.011). Mean CCT measurements between UP and Lenstar were similar (p = 0.769). Measurements with Lenstar (r = 0.849), Sirius topography (r = 0.883), and RTVue OCT (0.949) were highly correlated with UP measurements. RTVue OCT and Sirius topography significantly underestimated the CCT compared with UP. Although highly correlated, the measurement values with these devices are not directly interchangeable in clinical practice.

Thermal safety of ultrasound-enhanced ocular drug delivery: A modeling study

PubMed Central

Nabili, Marjan; Geist, Craig; Zderic, Vesna

2015-01-01

Purpose: Delivery of sufficient amounts of therapeutic drugs into the eye for treatment of various ocular diseases is often a challenging task. Ultrasound was shown to be effective in enhancing ocular drug delivery in the authors’ previous in vitro and in vivo studies. Methods: The study reported here was designed to investigate the safety of ultrasound application and its potential thermal effects in the eye using PZFlex modeling software. The safety limit in this study was set as a temperature increase of no more than 1.5 °C based on regulatory recommendations and previous experimental safety studies. Acoustic and thermal specifications of different human eye tissues were obtained from the published literature. The tissues of particular interest in this modeling safety study were cornea, lens, and the location of optic nerve in the posterior eye. Ultrasound application was modeled at frequencies of 400 kHz–1 MHz, intensities of 0.3–1 W/cm2, and exposure duration of 5 min, which were the parameters used in the authors’ previous drug delivery experiments. The baseline eye temperature was 37 °C. Results: The authors’ results showed that the maximal tissue temperatures after 5 min of ultrasound application were 38, 39, 39.5, and 40 °C in the cornea, 39.5, 40, 42, and 43 °C in the center of the lens, and 37.5, 38.5, and 39 °C in the back of the eye (at the optic nerve location) at frequencies of 400, 600, 800 kHz, and 1 MHz, respectively. Conclusions: The ocular temperatures reached at higher frequencies were considered unsafe based on current recommendations. At a frequency of 400 kHz and intensity of 0.8 W/cm2 (parameters shown in the authors’ previous in vivo studies to be optimal for ocular drug delivery), the temperature increase was small enough to be considered safe inside different ocular tissues. However, the impact of orbital bone and tissue perfusion should be included in future modeling efforts to determine the safety of this

Thermal safety of ultrasound-enhanced ocular drug delivery: A modeling study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nabili, Marjan, E-mail: mnabili@gwmail.gwu.edu; Geist, Craig, E-mail: cgeist@mfa.gwu.edu, E-mail: zderic@gwu.edu; Zderic, Vesna, E-mail: cgeist@mfa.gwu.edu, E-mail: zderic@gwu.edu

Purpose: Delivery of sufficient amounts of therapeutic drugs into the eye for treatment of various ocular diseases is often a challenging task. Ultrasound was shown to be effective in enhancing ocular drug delivery in the authors’ previous in vitro and in vivo studies. Methods: The study reported here was designed to investigate the safety of ultrasound application and its potential thermal effects in the eye using PZFlex modeling software. The safety limit in this study was set as a temperature increase of no more than 1.5 °C based on regulatory recommendations and previous experimental safety studies. Acoustic and thermal specifications ofmore » different human eye tissues were obtained from the published literature. The tissues of particular interest in this modeling safety study were cornea, lens, and the location of optic nerve in the posterior eye. Ultrasound application was modeled at frequencies of 400 kHz–1 MHz, intensities of 0.3–1 W/cm{sup 2}, and exposure duration of 5 min, which were the parameters used in the authors’ previous drug delivery experiments. The baseline eye temperature was 37 °C. Results: The authors’ results showed that the maximal tissue temperatures after 5 min of ultrasound application were 38, 39, 39.5, and 40 °C in the cornea, 39.5, 40, 42, and 43 °C in the center of the lens, and 37.5, 38.5, and 39 °C in the back of the eye (at the optic nerve location) at frequencies of 400, 600, 800 kHz, and 1 MHz, respectively. Conclusions: The ocular temperatures reached at higher frequencies were considered unsafe based on current recommendations. At a frequency of 400 kHz and intensity of 0.8 W/cm{sup 2} (parameters shown in the authors’ previous in vivo studies to be optimal for ocular drug delivery), the temperature increase was small enough to be considered safe inside different ocular tissues. However, the impact of orbital bone and tissue perfusion should be included in future modeling efforts to determine

21 CFR 886.3200 - Artificial eye.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device resembling the anterior portion of the eye, usually made of glass or plastic, intended to be...

21 CFR 886.3200 - Artificial eye.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device resembling the anterior portion of the eye, usually made of glass or plastic, intended to be...

21 CFR 886.3200 - Artificial eye.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device resembling the anterior portion of the eye, usually made of glass or plastic, intended to be...

Emerging Non-Cancer Applications of Therapeutic Ultrasound

PubMed Central

O’Reilly, Meaghan A.; Hynynen, Kullervo

2015-01-01

Ultrasound therapy has been investigated for over half a century. Ultrasound can act on tissue through a variety of mechanisms, including thermal, shockwave and cavitation mechanisms, and through these can elicit different responses. Ultrasound therapy can provide a non-invasive or minimally invasive treatment option, and ultrasound technology has advanced to the point where devices can be developed to investigate a wide range of applications. This review focuses on non-cancer, clinical applications of therapeutic ultrasound, with an emphasis on treatments that have recently reached clinical investigations, and preclinical research programs that have great potential to impact patient care. PMID:25792225

Ultrasound-guided venous access for pacemakers and defibrillators.

PubMed

Seto, Arnold H; Jolly, Aaron; Salcedo, Jonathan

2013-03-01

Ultrasound guidance is widely recommended to reduce the risk of complications during central venous catheter placement. However, ultrasound guidance is not commonly utilized for implanting leads for cardiac rhythm management devices. We describe our technique of ultrasound-guided pacemaker implantation, including a novel pull-through technique that allows percutaneous guidewire insertion prior to the first incision. We review the literature and recent advances in ultrasound imaging technology that may facilitate the adoption of ultrasound guidance. Ultrasound guidance provides a safe and rapid technique for extrathoracic subclavian or axillary venous lead placement. © 2012 Wiley Periodicals, Inc.

New heights in ultrasound: first report of spinal ultrasound from the international space station.

PubMed

Marshburn, Thomas H; Hadfield, Chris A; Sargsyan, Ashot E; Garcia, Kathleen; Ebert, Douglas; Dulchavsky, Scott A

2014-01-01

Changes in the lumbar and sacral spine occur with exposure to microgravity in astronauts; monitoring these alterations without radiographic capabilities on the International Space Station (ISS) requires novel diagnostic solutions to be developed. We evaluated the ability of point-of-care ultrasound, performed by nonexpert-operator astronauts, to provide accurate anatomic information about the spine in long-duration crewmembers in space. Astronauts received brief ultrasound instruction on the ground and performed in-flight cervical and lumbosacral ultrasound examinations using just-in-time training and remote expert tele-ultrasound guidance. Ultrasound examinations on the ISS used a portable ultrasound device with real-time communication/guidance with ground experts in Mission Control. The crewmembers were able to obtain diagnostic-quality examinations of the cervical and lumbar spine that would provide essential information about acute or chronic changes to the spine. Spinal ultrasound provides essential anatomic information in the cervical and lumbosacral spine; this technique may be extensible to point-of-care situations in emergency departments or resource-challenged areas without direct access to additional radiologic capabilities. Copyright © 2014 Elsevier Inc. All rights reserved.

Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography

PubMed Central

Yeo, Joon Hyung; Moon, Nam Ju

2017-01-01

Purpose To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Methods Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. Results The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The two methods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots were used to demonstrate the agreement between the two methods. Conclusions We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. PMID:28471103

Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography.

PubMed

Yeo, Joon Hyung; Moon, Nam Ju; Lee, Jeong Kyu

2017-06-01

To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The two methods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots were used to demonstrate the agreement between the two methods. We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. © 2017 The Korean Ophthalmological Society

21 CFR 878.4590 - Focused ultrasound stimulator system for aesthetic use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Focused ultrasound stimulator system for aesthetic....4590 Focused ultrasound stimulator system for aesthetic use. (a) Identification. A Focused Ultrasound Stimulator System for Aesthetic Use is a device using focused ultrasound to produce localized, mechanical...

21 CFR 878.4590 - Focused ultrasound stimulator system for aesthetic use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Focused ultrasound stimulator system for aesthetic....4590 Focused ultrasound stimulator system for aesthetic use. (a) Identification. A Focused Ultrasound Stimulator System for Aesthetic Use is a device using focused ultrasound to produce localized, mechanical...

21 CFR 878.4590 - Focused ultrasound stimulator system for aesthetic use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Focused ultrasound stimulator system for aesthetic....4590 Focused ultrasound stimulator system for aesthetic use. (a) Identification. A Focused Ultrasound Stimulator System for Aesthetic Use is a device using focused ultrasound to produce localized, mechanical...

Virtual Guidance Ultrasound: A Tool to Obtain Diagnostic Ultrasound for Remote Environments

NASA Technical Reports Server (NTRS)

Caine,Timothy L.; Martin David S.; Matz, Timothy; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.

2012-01-01

Astronauts currently acquire ultrasound images on the International Space Station with the assistance of real-time remote guidance from an ultrasound expert in Mission Control. Remote guidance will not be feasible when significant communication delays exist during exploration missions beyond low-Earth orbit. For example, there may be as much as a 20- minute delay in communications between the Earth and Mars. Virtual-guidance, a pre-recorded audio-visual tutorial viewed in real-time, is a viable modality for minimally trained scanners to obtain diagnostically-adequate images of clinically relevant anatomical structures in an autonomous manner. METHODS: Inexperienced ultrasound operators were recruited to perform carotid artery (n = 10) and ophthalmic (n = 9) ultrasound examinations using virtual guidance as their only instructional tool. In the carotid group, each each untrained operator acquired two-dimensional, pulsed, and color Doppler of the carotid artery. In the ophthalmic group, operators acquired representative images of the anterior chamber of the eye, retina, optic nerve, and nerve sheath. Ultrasound image quality was evaluated by independent imaging experts. RESULTS: Eight of the 10 carotid studies were judged to be diagnostically adequate. With one exception the quality of all the ophthalmic images were adequate to excellent. CONCLUSION: Diagnostically-adequate carotid and ophthalmic ultrasound examinations can be obtained by untrained operators with instruction only from an audio/video tutorial viewed in real time while scanning. This form of quick-response-guidance, can be developed for other ultrasound examinations, represents an opportunity to acquire important medical and scientific information for NASA flight surgeons and researchers when trained medical personnel are not present. Further, virtual guidance will allow untrained personnel to autonomously obtain important medical information in remote locations on Earth where communication is

Comparison of Central Corneal Thickness Measured by Standard Ultrasound Pachymetry, Corneal Topography, Tono-Pachymetry and Anterior Segment Optical Coherence Tomography.

PubMed

González-Pérez, Javier; Queiruga Piñeiro, Juan; Sánchez García, Ángelx; González Méijome, José Manuel

2018-04-10

To compare central corneal thickness (CCT) measured by standard ultrasound pachymetry (USP), and three non-contact devices in healthy eyes. A cross-sectional study of CCT measurement in 52 eyes of 52 healthy volunteers was done by a single examiner at Ocular Surface and Contact Lens Laboratory. Three consecutive measurements were done by standard USP, non-contact tono-pachymeter, Pentacam corneal topographer, and Anterior Segment Optical Coherence Tomography (AS-OCT). The mean values were used for assessment. The results were compared using multivariate ANOVA, linear regression, and Pearson correlation. Agreement among the devices was analyzed using mean differences and Bland-Altman analysis with 95% limits of agreement (LoA). Finally, reliability was analyzed using intraclass correlation coefficient (ICC). Mean CCT by ultrasound pachymeter, tono-pachymeter, corneal topographer and AS-OCT were 558.9 ± 31.2 µm, 525.8 ± 43.1 µm, 550.4 ± 30.5 µm, and 545.9 ± 30.5 µm respectively. There was a significant positive correlation between AS-OCT and USP (Pearson correlation = 0.957, p < 0.001), corneal topography and USP (Pearson correlation = 0.965, p < 0.001), and corneal topography and AS-OCT (Pearson correlation = 0.965, p < 0.001). There was a lower correlation between CT-1P tono-pachymeter and the other three modalities. Intraclass correlation coefficients show an excellent reliability between pairs except for CT-1P against the other three instruments that were found moderate. CT-1P tono-pachymeter underestimates CCT measurements compared to Scheimpflug system, AS-OCT device, and USP. Mean CCT among USP, Pentacam and AS-OCT were comparable and had significant linear correlations. In clinical practice, these three modalities could be interchangeable in healthy patients.

Optical micromachined ultrasound transducers (OMUT)--a new approach for high-frequency transducers.

PubMed

Tadayon, Mohammad Amin; Ashkenazi, Shai

2013-09-01

The sensitivity and reliability of piezoelectric ultrasound transducers severely degrade in applications requiring high frequency and small element size. Alternative technologies such as capacitive micromachined ultrasound transducers (CMUT) and optical sensing and generation of ultrasound have been proposed and studied for several decades. In this paper, we present a new type of device based on optical micromachined ultrasound transducer (OMUT) technology. OMUTs rely on microfabrication techniques to construct micrometerscale air cavities capped by an elastic membrane. A modified photoresist bonding process has been developed to facilitate the fabrication of these devices. We will describe the design, fabrication, and testing of prototype OMUT devices which implement a receive-only function. Future design modifications are proposed for incorporating complete transmit¿receive functionality in a single element.

Ultrasound biomicroscopy after canaloplasty: clinical study with two different units.

PubMed

Doro, Daniele; Koerber, Norbert; Paolucci, Pierpaolo; Cimatti, Pierangela

2012-12-01

Canaloplasty is a recent non penetrating glaucoma surgical procedure where Schlemm's canal is dilated and trabecular meshwork distended by tensioning polypropylene suture. The aim of this study was to visualize the iridocorneal angle after the canaloplasty procedure by means of two different ultrasound biomicroscopy (UBM) units. Ten eyes of nine patients with primary open angle glaucoma (average age 62 years) underwent canaloplasty (six eyes) or canaloplasty combined with phacoemulsification and in-the-bag intraocular lens implantation (4 eyes). Both 50 MHz (Paradigm P45) and 80 MHz (i-UltraSound) systems were used. All procedures were performed by the same surgeon. UBM examination was performed 3 to 12 (mean 7 +/- 3.1) months after surgery. No, mild and good trabecular meshwork distension by suture tensioning was graded as 0, 1 and 2 according to the higher resolution 80 MHz images. Both ultrasound systems could show intrascleral lake and trabecular meshwork distension, which was graded as 0, 1 and 2 in 10%, 30% and 60% of eyes, respectively. Schlemm's canal could be imaged with the 80 MHz transducer only. The overall qualified success of canaloplasty (80%) was apparently correlated with suture tensioning (r=0.64). In our experience, after canaloplasty the 80 MHz but also 50 MHz technology can show trabecular meshwork distension. A greater number of eyes are needed to assess the correlation between intraocular pressure decrease and suture tensioning.

Distributed Network, Wireless and Cloud Computing Enabled 3-D Ultrasound; a New Medical Technology Paradigm

PubMed Central

Meir, Arie; Rubinsky, Boris

2009-01-01

Medical technologies are indispensable to modern medicine. However, they have become exceedingly expensive and complex and are not available to the economically disadvantaged majority of the world population in underdeveloped as well as developed parts of the world. For example, according to the World Health Organization about two thirds of the world population does not have access to medical imaging. In this paper we introduce a new medical technology paradigm centered on wireless technology and cloud computing that was designed to overcome the problems of increasing health technology costs. We demonstrate the value of the concept with an example; the design of a wireless, distributed network and central (cloud) computing enabled three-dimensional (3-D) ultrasound system. Specifically, we demonstrate the feasibility of producing a 3-D high end ultrasound scan at a central computing facility using the raw data acquired at the remote patient site with an inexpensive low end ultrasound transducer designed for 2-D, through a mobile device and wireless connection link between them. Producing high-end 3D ultrasound images with simple low-end transducers reduces the cost of imaging by orders of magnitude. It also removes the requirement of having a highly trained imaging expert at the patient site, since the need for hand-eye coordination and the ability to reconstruct a 3-D mental image from 2-D scans, which is a necessity for high quality ultrasound imaging, is eliminated. This could enable relatively untrained medical workers in developing nations to administer imaging and a more accurate diagnosis, effectively saving the lives of people. PMID:19936236

Distributed network, wireless and cloud computing enabled 3-D ultrasound; a new medical technology paradigm.

PubMed

Meir, Arie; Rubinsky, Boris

2009-11-19

Medical technologies are indispensable to modern medicine. However, they have become exceedingly expensive and complex and are not available to the economically disadvantaged majority of the world population in underdeveloped as well as developed parts of the world. For example, according to the World Health Organization about two thirds of the world population does not have access to medical imaging. In this paper we introduce a new medical technology paradigm centered on wireless technology and cloud computing that was designed to overcome the problems of increasing health technology costs. We demonstrate the value of the concept with an example; the design of a wireless, distributed network and central (cloud) computing enabled three-dimensional (3-D) ultrasound system. Specifically, we demonstrate the feasibility of producing a 3-D high end ultrasound scan at a central computing facility using the raw data acquired at the remote patient site with an inexpensive low end ultrasound transducer designed for 2-D, through a mobile device and wireless connection link between them. Producing high-end 3D ultrasound images with simple low-end transducers reduces the cost of imaging by orders of magnitude. It also removes the requirement of having a highly trained imaging expert at the patient site, since the need for hand-eye coordination and the ability to reconstruct a 3-D mental image from 2-D scans, which is a necessity for high quality ultrasound imaging, is eliminated. This could enable relatively untrained medical workers in developing nations to administer imaging and a more accurate diagnosis, effectively saving the lives of people.

A Proposed Method for Upper Eyelid and Infrabrow Tightening Using a Transcutaneous Temperature Controlled Radiofrequency Device With Opaque Plastic Eye Shields.

PubMed

Key, Douglas J; Boudreaux, Lauren

2016-11-01

Laxity of the eyelid and periorbital area, a common manifestation of aging, is usually addressed via blepharoplasty and/ or fat transfer. Given the trend toward safer, less invasive treatments preferred by those patients reticent to undergo more invasive procedures, viable alternatives have been sought. Transcutaneous temperature controlled radiofrequency (TTCRF) integrates non- invasive super cial RF treatment with automatic temperature feedback control of energy deposition, as a stimulator of overall collagen remodeling; however, the globe of the eye is particularly sensitive to RF energy. The purpose of the study was to propose a method by which TTCRF and other non-ablative modalities could be used to treat eyelid and infrabrow laxity, with autoclavable opaque black haptic scleral contact lenses protecting the globe of the eye. Subjects (n=40, 36 women and 4 men, age range, 33-72) with mild to moderate laxity of the eyelid and infrabrow were treated with TTCRF using black plastic eye shields (Oculoplastik, Montreal, Quebec, Canada) to protect the globe of the eye from heat and RF energy. With the shields in place subjects were treated with the 10 mm small monopolar emitter of the ThermiSmooth device (Thermi, Irving, Tex.), using small circular looping motions to safely elevate the temperature of target tissue to the therapeutically rel- evant range for approximately 6 minutes; tissue temperature was measured in real time using the device's forward-looking infrared imaging. No major adverse events were recorded. Treatment was safe and tolerable for all subjects. The use of autoclavable opaque black plastic eye shields provides a safe method of treating the upper eye lid and infrabrow using TTCRF. J Drugs Dermatol. 2016;15(11):1302-1305..

Extracting information of fixational eye movements through pupil tracking

NASA Astrophysics Data System (ADS)

Xiao, JiangWei; Qiu, Jian; Luo, Kaiqin; Peng, Li; Han, Peng

2018-01-01

Human eyes are never completely static even when they are fixing a stationary point. These irregular, small movements, which consist of micro-tremors, micro-saccades and drifts, can prevent the fading of the images that enter our eyes. The importance of researching the fixational eye movements has been experimentally demonstrated recently. However, the characteristics of fixational eye movements and their roles in visual process have not been explained clearly, because these signals can hardly be completely extracted by now. In this paper, we developed a new eye movement detection device with a high-speed camera. This device includes a beam splitter mirror, an infrared light source and a high-speed digital video camera with a frame rate of 200Hz. To avoid the influence of head shaking, we made the device wearable by fixing the camera on a safety helmet. Using this device, the experiments of pupil tracking were conducted. By localizing the pupil center and spectrum analysis, the envelope frequency spectrum of micro-saccades, micro-tremors and drifts are shown obviously. The experimental results show that the device is feasible and effective, so that the device can be applied in further characteristic analysis.

Delay and Standard Deviation Beamforming to Enhance Specular Reflections in Ultrasound Imaging.

PubMed

Bandaru, Raja Sekhar; Sornes, Anders Rasmus; Hermans, Jeroen; Samset, Eigil; D'hooge, Jan

2016-12-01

Although interventional devices, such as needles, guide wires, and catheters, are best visualized by X-ray, real-time volumetric echography could offer an attractive alternative as it avoids ionizing radiation; it provides good soft tissue contrast, and it is mobile and relatively cheap. Unfortunately, as echography is traditionally used to image soft tissue and blood flow, the appearance of interventional devices in conventional ultrasound images remains relatively poor, which is a major obstacle toward ultrasound-guided interventions. The objective of this paper was therefore to enhance the appearance of interventional devices in ultrasound images. Thereto, a modified ultrasound beamforming process using conventional-focused transmit beams is proposed that exploits the properties of received signals containing specular reflections (as arising from these devices). This new beamforming approach referred to as delay and standard deviation beamforming (DASD) was quantitatively tested using simulated as well as experimental data using a linear array transducer. Furthermore, the influence of different imaging settings (i.e., transmit focus, imaging depth, and scan angle) on the obtained image contrast was evaluated. The study showed that the image contrast of specular regions improved by 5-30 dB using DASD beamforming compared with traditional delay and sum (DAS) beamforming. The highest gain in contrast was observed when the interventional device was tilted away from being orthogonal to the transmit beam, which is a major limitation in standard DAS imaging. As such, the proposed beamforming methodology can offer an improved visualization of interventional devices in the ultrasound image with potential implications for ultrasound-guided interventions.

Using an auditory sensory substitution device to augment vision: evidence from eye movements.

PubMed

Wright, Thomas D; Margolis, Aaron; Ward, Jamie

2015-03-01

Sensory substitution devices convert information normally associated with one sense into another sense (e.g. converting vision into sound). This is often done to compensate for an impaired sense. The present research uses a multimodal approach in which both natural vision and sound-from-vision ('soundscapes') are simultaneously presented. Although there is a systematic correspondence between what is seen and what is heard, we introduce a local discrepancy between the signals (the presence of a target object that is heard but not seen) that the participant is required to locate. In addition to behavioural responses, the participants' gaze is monitored with eye-tracking. Although the target object is only presented in the auditory channel, behavioural performance is enhanced when visual information relating to the non-target background is presented. In this instance, vision may be used to generate predictions about the soundscape that enhances the ability to detect the hidden auditory object. The eye-tracking data reveal that participants look for longer in the quadrant containing the auditory target even when they subsequently judge it to be located elsewhere. As such, eye movements generated by soundscapes reveal the knowledge of the target location that does not necessarily correspond to the actual judgment made. The results provide a proof of principle that multimodal sensory substitution may be of benefit to visually impaired people with some residual vision and, in normally sighted participants, for guiding search within complex scenes.

Grooved Glaucoma Drainage Devices That Continuously Deliver Cyclosporine A Decrease Postsurgical Scar Formation in Rabbit Eyes.

PubMed

Dai, Zhaoxing; Yu, Xiaobo; Sun, Jianguo; Sun, Xinghuai

2017-03-01

To study the functional outcomes of filtration surgery by implanting improved glaucoma drainage devices (GDDs) comprising surface grooves and a composite coating of cyclosporine A (CsA) and PLGA in experimental rabbit eyes. Improved GDDs were designed and prepared by modifying normal GDD with surface grooves and a CsA-PLGA composite coating. Normal GDDs, grooved GDDs (G-GDDs), and G-GDDs with a CsA-PLGA composite coating (CsA@G-GDD) were implanted into 18 rabbit eyes (six eyes per group). The intraocular pressure (IOP), bleb survival time, bleb morphology, and anterior chamber reactions were assessed for up to 12 weeks after GDD implantation. The IOPs were compared statistically among the three groups. Bleb morphology was quantified using the Indiana Bleb Appearance Grading Scale. Anterior chamber radiography was performed to check whether the filtrating pathway was blocked, and determine the drainage time and diffusion area of the contrast agent. Hematoxylin and eosin staining and immunohistochemistry were conducted to assess how the GDDs slowed or prevented scar formation. The improved GDDs were successfully prepared and implanted in 18 rabbit eyes without severe surgical complications. Bleb survival time was significantly longer and IOP was significantly lower in the G-GDD and CsA@G-GDD groups compared with the GDD group (all, P < 0.001). Blebs were significantly higher in the CsA@G-GDD group than in the GDD and G-GDD groups (P = 0.003). Anterior chamber radiography revealed more unobstructed filtration channels in the CsA@G-GDD group than in the GDD group (P = 0.032). Postsurgical scar formation was less extensive in the G-GDD and CsA@G-GDD groups than in the GDD group. Compared with the normal GDDs, G-GDDs with a CsA-PLGA coating inhibited postsurgical scar formation and improved the surgical success rate, and might represent an alternative to existing glaucoma filtration devices.

Pocket ultrasound device as a complement to physical examination for ascites evaluation and guided paracentesis.

PubMed

Keil-Ríos, Daniel; Terrazas-Solís, Hiram; González-Garay, Alejandro; Sánchez-Ávila, Juan Francisco; García-Juárez, Ignacio

2016-04-01

The pocket ultrasound device (PUD) is a new tool that may be of use in the early detection of ascites. Abdominal ultrasound-guided paracentesis has been reported to decrease the rate of complications due to the procedure, but must be performed in a healthcare setting; this new tool may be a useful on an ambulatory basis. The aim of this study was to determine the diagnostic usefulness of the PUD in the diagnosis of ascites and the safety of guided paracentesis. We conducted a retrospective study that included adult patients suspected of having ascites and in whom an evaluation was performed with the PUD to identify it. Concordance with abdominal ultrasound (AUS) was determined with the Kappa coefficient. Sensitivity (Se), specificity (Sp) and likelihood ratios (LR) were determined and compared with physical examination, AUS, computed tomography and procurement of fluid by paracentesis. Complications resulting from the guided paracentesis were analyzed. 89 participants were included and 40 underwent a paracentesis. The PUD for ascites detection had 95.8 % Se, 81.8 % Sp, 5.27 +LR and 0.05 -LR. It had a concordance with AUS of 0.781 (p < 0.001). Technical problems during the guided paracentesis were present in only two participants (5 %) and three patients (7.5 %) developed minor complications that required no further intervention. There were no severe complications or deaths. This study suggests that the PUD is a reliable tool for ascites detection as a complement to physical examination and appears to be a safe method to perform guided paracentesis.

Endobronchial Ultrasound-guided Transbronchial Needle Aspiration With a 19-G Needle Device.

PubMed

Tremblay, Alain; McFadden, Seamus; Bonifazi, Martina; Luzzi, Valentina; Kemp, Samuel V; Gasparini, Stefano; Chee, Alex; MacEachern, Paul; Dumoulin, Elaine; A Hergott, Christopher; Shah, Pallav L

2018-05-16

Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration is a well-established first-line minimally invasive modality for mediastinal lymph node sampling. Although results are excellent overall, the technique underperforms in certain situations. We aimed to describe our results using a new 19-G EBUS-guided transbronchial needle aspiration device to determine safety and feasibility of this approach. We completed a retrospective chart review of all cases performed to the time of data analysis at each of 3 study sites. A total of 165 procedures were performed with a total of 297 individual lymph nodes or lesions sampled with the 19-G device by 10 bronchoscopists. Relatively large targets were selected for sampling with the device (mean lymph node size: 20.4 mm; lung lesions: 33.5 mm). A specific diagnosis was obtained in 77.3% of cases with an additional 13.6% of cases with benign lymphocytes, for a procedural adequacy rate of 90.9%. Procedure sample adequacy was 88.6% in suspected malignant cases, 91.0% in suspected sarcoidosis/lymphadenopathy cases, and 85.7% of cases with suspected lymphoma. On a per-node basis, a specific diagnosis was noted in 191/280 (68.2%) of samples, with an additional 61 showing benign lymphocytes for a per-node sample adequacy rate of 90%. One case (0.6%) of intraprocedure bleeding was noted. A new flexible 19-G EBUS needle was successfully and safely applied in a large patient cohort for sampling of lung and enlarged mediastinal lesions with high diagnostic rates across clinical indications.

Human eye-inspired soft optoelectronic device using high-density MoS2-graphene curved image sensor array.

PubMed

Choi, Changsoon; Choi, Moon Kee; Liu, Siyi; Kim, Min Sung; Park, Ok Kyu; Im, Changkyun; Kim, Jaemin; Qin, Xiaoliang; Lee, Gil Ju; Cho, Kyoung Won; Kim, Myungbin; Joh, Eehyung; Lee, Jongha; Son, Donghee; Kwon, Seung-Hae; Jeon, Noo Li; Song, Young Min; Lu, Nanshu; Kim, Dae-Hyeong

2017-11-21

Soft bioelectronic devices provide new opportunities for next-generation implantable devices owing to their soft mechanical nature that leads to minimal tissue damages and immune responses. However, a soft form of the implantable optoelectronic device for optical sensing and retinal stimulation has not been developed yet because of the bulkiness and rigidity of conventional imaging modules and their composing materials. Here, we describe a high-density and hemispherically curved image sensor array that leverages the atomically thin MoS 2 -graphene heterostructure and strain-releasing device designs. The hemispherically curved image sensor array exhibits infrared blindness and successfully acquires pixelated optical signals. We corroborate the validity of the proposed soft materials and ultrathin device designs through theoretical modeling and finite element analysis. Then, we propose the ultrathin hemispherically curved image sensor array as a promising imaging element in the soft retinal implant. The CurvIS array is applied as a human eye-inspired soft implantable optoelectronic device that can detect optical signals and apply programmed electrical stimulation to optic nerves with minimum mechanical side effects to the retina.

Randomized sham-controlled trial to evaluate the safety and effectiveness of a high-intensity focused ultrasound device for noninvasive body sculpting.

PubMed

Jewell, Mark L; Baxter, Richard A; Cox, Sue Ellen; Donofrio, Lisa M; Dover, Jeffrey S; Glogau, Richard G; Kane, Michael A; Weiss, Robert A; Martin, Patrick; Schlessinger, Joel

2011-07-01

High-intensity focused ultrasound presents a noninvasive approach to body sculpting for nonobese patients. The purpose of this study was to evaluate the safety and effectiveness of a high-intensity focused ultrasound device for sculpting of the abdomen and flanks. Adults (aged 18 to 65 years) with subcutaneous abdominal fat greater than or equal to 2.5 cm thick who met screening criteria were randomized to receive high-intensity focused ultrasound treatment of the anterior abdomen and flanks at energy levels (a total of three passes each) of 47 J/cm (141 J/cm total), 59 J/cm (177 J/cm), or 0 J/cm (no energy applied, sham control). The primary endpoint was change from baseline waist circumference at the iliac crest level at posttreatment week 12. Subjective aesthetic assessments included the Global Aesthetic Improvement Scale and a patient satisfaction questionnaire. Safety assessments included adverse events, laboratory values, and physical examinations. For the primary endpoint, in the intent-to-treat population, statistical significance versus sham was achieved for the 59-J/cm (-2.44; p = 0.01) but not the 47-J/cm treatment group (-2.06 cm; p = 0.13). In a per-protocol population, statistical significance versus sham was achieved for both the 59-J/cm (-2.52 cm; p = 0.002) and the 47-J/cm treatment groups (-2.10 cm; p = 0.04). Investigator subjective measures of global aesthetic improvement and patient satisfaction also favored each active treatment versus sham. Adverse events included mild to moderate discomfort, bruising, and edema. Laboratory values and physical examinations were unremarkable. Treatment with this high-intensity focused ultrasound device reduced waist circumference and was generally well tolerated for noninvasive body sculpting. Reduction in waist circumference was statistically significant with both active treatments (per protocol). Therapeutic, II.(Figure is included in full-text article.).

Design of an ergonomic ultrasound system: accommodation of user anthropometrics.

PubMed

Park, Sung; Yim, Jinho; Lee, Goeun

2012-01-01

Long-term use of medical imaging devices requires significant improvements to the user experience. One factor that impact upon such experience is whether the device is ergonomically built, ecologically designed, and leverages the current medical practice. In this research, we took a holistic and systematic approach to design an effective and biomechanically-fit ultrasound system. Research methods from behavior science (e.g., contextual inquiry, pseudo experiments) had been adopted to involve the users (sonographers) early in the design process. The end results - product design guideline for a cart type ultrasound system and control panel layout - were reviewed by the users and adjusted so that the design is within the range of an acceptable learning curve while maintaining innovativeness, a differentiated value over competitor's ultrasound devices.

Bio-inspired hemispherical compound eye camera

NASA Astrophysics Data System (ADS)

Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

2014-03-01

Compound eyes in arthropods demonstrate distinct imaging characteristics from human eyes, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. Artificial imaging systems with similar geometries and properties are of great interest for many applications. However, the challenges in building such systems with hemispherical, compound apposition layouts cannot be met through established planar sensor technologies and conventional optics. We present our recent progress in combining optics, materials, mechanics and integration schemes to build fully functional artificial compound eye cameras. Nearly full hemispherical shapes (about 160 degrees) with densely packed artificial ommatidia were realized. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors, which were fabricated in the planar geometries and then integrated and elastically transformed to hemispherical shapes. Imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

Imaging late capsular block syndrome: ultrasound biomicroscopy versus Scheimpflug camera.

PubMed

Kucukevcilioglu, Murat; Hurmeric, Volkan; Erdurman, Fazıl Cuneyt; Ceylan, Osman Melih

2011-11-01

We describe 2 patients with late capsular block syndrome whose anterior chamber morphology was evaluated with ultrasound biomicroscopy and Scheimpflug imaging before and after neodymium:YAG laser capsulotomy. Pretreatment ultrasound biomicroscopy examination showed significant capsular bag distension in both patients. Scheimpflug imaging failed to capture the posterior capsule displaced far behind the intraocular lens. Automatic anterior chamber depth measurements were incorrect with Scheimpflug imaging in 1 patient. Ultrasound biomicroscopy seems to be superior to Scheimpflug imaging in eyes with extremely distended capsular bags. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Simulation of ultrasound propagation in bone

NASA Astrophysics Data System (ADS)

Kaufman, Jonathan J.; Luo, Gangming; Siffert, Robert S.

2004-10-01

Ultrasound has been proposed as a means to noninvasively assess bone and, particularly, bone strength and fracture risk, as for example in osteoporosis. Because strength is a function of both mineral density and architecture, ultrasound has the potential to provide more accurate measurement of bone integrity than, for example, with x-ray absorptiometric methods. Although some of this potential has already been realized-a number of clinical devices are presently available-there is still much that is unknown regarding the interaction of ultrasound with bone. Because of the inherent complexity of the propagation medium, few analytic solutions exist with practical application. For this reason, ultrasound simulation techniques have been developed and applied to a number of different problems of interest in ultrasonic bone assessment. Both 2D and 3D simulation results will be presented, including the effects of architecture and density on the received waveform, propagation effects of both cortical and trabecular bone, and the relative contributions of scattering and absorption to attenuation in trabecular bone. The results of these simulation studies should lead to improved understanding and ultimately to more effective clinical devices for ultrasound bone assessment. [This work was supported by The Carroll and Milton Petrie Foundation and by SBIR Grant No. 1R43RR16750 from the National Center for Research Resources of the NIH.

21 CFR 880.5270 - Neonatal eye pad.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy. (b...

21 CFR 880.5270 - Neonatal eye pad.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy. (b...

Performance of the SRK/T formula using A-Scan ultrasound biometry after phacoemulsification in eyes with short and long axial lengths.

PubMed

Karabela, Yunus; Eliacik, Mustafa; Kaya, Faruk

2016-07-08

The SRK/T formula is one of the third generation IOL calculation formulas. The purpose of this study was to evaluate the performance of the SRK/T formula in predicting a target refraction ±1.0D in short and long eyes using ultrasound biometry after phacoemulsification. The present study was a retrospective analysis, which included 38 eyes with an AL < 22.0 mm (short AL), and 62 eyes ≥24.6 mm (long AL) that underwent uncomplicated phacoemulsification. Preoperative AL was measured by ultrasound biometry and SRK/T formula was used for IOL calculation. Three different IOLs were implanted in the capsular bag. The prediction error was defined as the difference between the achieved postoperative refraction, and attempted predicted target refraction. Statistical analysis was performed with SPSS V21. In short ALs, the mean age was 65.13 ± 9.49 year, the mean AL was 21.55 ± 0.45 mm, the mean K1 and K2 were 45.76 ± 1.77D and 46.09 ± 1.61D, the mean IOL power was 23.96 ± 1.92D, the mean attempted (predicted) value was 0.07 ± 0.26D, the mean achieved value was 0.07 ± 0.63 D, the mean PE was 0.01 ± 0.60D, and the MAE was 0.51 ± 0.31D. A significant positive relationship with AL and K1, K2, IOL power and a strong negative relationship with PE and achieved postoperative was found. In long ALs, the mean age was 64.05 ± 7.31 year, the mean AL was 25.77 ± 1.64 mm, the mean K1 and K2 were 42.20 ± 1.57D and 42.17 ± 1.68D, the mean IOL power was 15.79 ± 5.17D, the mean attempted value was -0.434 ± 0.315D, the mean achieved value was -0.42 ± 0.96D, the mean PE was -0.004 ± 0.93D, the MAE was 0.68 ± 0.62D. A significant positive relationship with AL and K1, K2 and a significant positive relationship with PE and achieved value, otherwise a negative relationship with AL and IOL power was found. There was a little tendency towards hyperopic for short ALs and myopic for long ALs. The majority of

Applicator for in-vitro ultrasound-activated targeted drug delivery

NASA Astrophysics Data System (ADS)

Gerold, B.; Gourevich, D.; Volovick, A.; Xu, D.; Arditti, F.; Prentice, P.; Cochran, S.; Gnaim, J.; Medan, Y.; Wang, L.; Melzer, A.

2012-10-01

Reducing toxicity and improving uptake of cancer drugs in tumors are important goals of targeted drug delivery (TDD). Ultrasonic drug release from various encapsulants has been a focus of many research groups. However, a single standard ultrasonic device, viable for use by biologists, is not currently present in the market. The device reported here is designed to allow investigation of the impact of ultrasound on cellular uptake and cell viability in-vitro. In it, single-element transducers with different operating frequencies are mounted below a standard 96-well plate. The plate is moved above the transducers, such that each line of wells can be sonicated at a different frequency. To assess the device, 96-well plates were seeded with cells and sonicated using different ultrasonic parameters, with and without doxorubicin. Cell viability was measured by colorimetric MTT assay and the uptake of doxorubicin by cells was also determined. The device proved to be highly viable in preliminary tests; it demonstrated that change in ultrasonic parameters produces different effect on cells. For example, increase in uptake of doxorubicin was demonstrated following ultrasound application. The growing interest in ultrasound-activated TDD emphasizes the need for standardization of the ultrasound device and the one reported here may offer some indications of how that may be achieved. It is planned to further improve the prototype by increasing the number of ultrasonic frequencies and degrees of freedom for each transducer.

Comparison of the biometric formulas used for applanation A-scan ultrasound biometry.

PubMed

Özcura, Fatih; Aktaş, Serdar; Sağdık, Hacı Murat; Tetikoğlu, Mehmet

2016-10-01

The purpose of the study was to compare the accuracy of various biometric formulas for predicting postoperative refraction determined using applanation A-scan ultrasound. This retrospective comparative study included 485 eyes that underwent uneventful phacoemulsification with intraocular lens (IOL) implantation. Applanation A-scan ultrasound biometry and postoperative manifest refraction were obtained in all eyes. Biometric data were entered into each of the five IOL power calculation formulas: SRK-II, SRK/T, Holladay I, Hoffer Q, and Binkhorst II. All eyes were divided into three groups according to axial length: short (≤22.0 mm), average (22.0-25.0 mm), and long (≥25.0 mm) eyes. The postoperative spherical equivalent was calculated and compared with the predicted refractive error using each biometric formula. The results showed that all formulas had significantly lower mean absolute error (MAE) in comparison with Binkhorst II formula (P < 0.01). The lowest MAE was obtained with the SRK-II for average (0.49 ± 0.40 D) and short (0.67 ± 0.54 D) eyes and the SRK/T for long (0.61 ± 0.50 D) eyes. The highest postoperative hyperopic shift was seen with the SRK-II for average (46.8 %), short (28.1 %), and long (48.4 %) eyes. The highest postoperative myopic shift was seen with the Holladay I for average (66.4 %) and long (71.0 %) eyes and the SRK/T for short eyes (80.6 %). In conclusion, the SRK-II formula produced the lowest MAE in average and short eyes and the SRK/T formula produced the lowest MAE in long eyes. The SRK-II has the highest postoperative hyperopic shift in all eyes. The highest postoperative myopic shift is with the Holladay I for average and long eyes and SRK/T for short eyes.

PLUS: open-source toolkit for ultrasound-guided intervention systems.

PubMed

Lasso, Andras; Heffter, Tamas; Rankin, Adam; Pinter, Csaba; Ungi, Tamas; Fichtinger, Gabor

2014-10-01

A variety of advanced image analysis methods have been under the development for ultrasound-guided interventions. Unfortunately, the transition from an image analysis algorithm to clinical feasibility trials as part of an intervention system requires integration of many components, such as imaging and tracking devices, data processing algorithms, and visualization software. The objective of our paper is to provide a freely available open-source software platform-PLUS: Public software Library for Ultrasound-to facilitate rapid prototyping of ultrasound-guided intervention systems for translational clinical research. PLUS provides a variety of methods for interventional tool pose and ultrasound image acquisition from a wide range of tracking and imaging devices, spatial and temporal calibration, volume reconstruction, simulated image generation, and recording and live streaming of the acquired data. This paper introduces PLUS, explains its functionality and architecture, and presents typical uses and performance in ultrasound-guided intervention systems. PLUS fulfills the essential requirements for the development of ultrasound-guided intervention systems and it aspires to become a widely used translational research prototyping platform. PLUS is freely available as open source software under BSD license and can be downloaded from http://www.plustoolkit.org.

Central corneal thickness measurements and ultrasonographic study of the growing equine eye.

PubMed

Herbig, Lena E; Eule, J Corinna

2015-11-01

The aim of this study was to determine the central corneal thickness (CCT) of healthy equine eyes with high-frequency ultrasound (HF) and ultrasound biomicroscopy (UBM) and to measure the axial dimensions with B-mode ultrasound. Additionally, the influence of the age on the measured dimensions of the globe was analyzed. Fifty warm blood horses (mean age 23.0 ± 21.12 months) were divided into 3 age groups (group 1: 0-6 months; group 2: ≥7-30 months; and group 3: ≥31-78 months). Corneal measurements were performed with a 22-MHz and a 50-MHz transducer. Crystalline lens thickness (CLT), vitreous chamber depth (VCD), and axial globe length (AGL) were measured at a frequency of 10 MHz. Anterior chamber depth (ACD) was calculated. The eyes were measured under general anesthesia nonrelated to this study. The mean CCT of 50 eyes was 818 ± 41 μm. The mean values ± SD in mm for axial dimensions were AGL 34.7 ± 2.7, ACD 3.4 ± 0.7, CLT 10.0 ± 0.9, and VCD of 20.4 ± 1.5. A positive correlation with increasing age was found for all dimensions. No significant differences were found between the gender and the left or right eye. HF and UBM are valuable high-resolution imaging tools for CCT measurements in horses. The here-obtained values support previous findings that a positive correlation with increasing age exists for CCT, ACD, CLT, VCD, and AGL in horse. © 2015 American College of Veterinary Ophthalmologists.

Efficacy of the Canabrava Ring (pupil expansion device) in cataract surgery for eyes with small pupils: the first 30 cases.

PubMed

Canabrava, Sérgio; Rezende, Pedro Henriques; Eliazar, Glauber Coutinho; Figueiredo, Sophia Barbosa de; Resende, Arthur Fernandes; Batista, Wagner Duarte; Diniz-Filho, Alberto

2018-06-01

To evaluate the outcomes of the first 30 cataract surgeries performed with a new disposable, injector-free, small-pupil expansion device. This consecutive case series included 30 eyes from 29 patients who underwent cataract surgery using a new disposable small-pupil expansion device called the Canabrava Ring (AJL Ophthalmic S.A, Spain). It is the first iris expansion ring produced with indents that do not align with each other in the superior and inferior regions, resulting in a small vertical length (0.4 mm) that minimizes the risk of endothelial contact. All eyes had poorly dilated pupils of less than 5 mm preoperatively. Fifteen eyes had significant infective or traumatic pathologies preoperatively. Vertical and horizontal pupil diameters were evaluated preoperatively, intraoperatively, and 1 month postoperatively. The mean patient age was 64 ± 11.8 (standard deviation) years. The Canabrava Ring remained engaged throughout all surgeries, except one. All pupils were intraoperatively expanded to a diameter of 6.3 mm. Although preexisting pathology on the innervation of the pupils, the mean pupil diameter returns to a close preoperative size after 1 month surgery. The mean pupil diameters postoperatively and preoperatively were 4.41 and 3.77 mm, respectively (p<0.05). Postoperative complications occurred in eight eyes (one toxoplasmosis reactivation, one retinal detachment, one posterior capsule rupture, one posterior capsule opacification, and four posterior synechiae). These complications occurred in eyes with preexisting traumatic or infective pathologies or synechiae. The Canabrava Ring is effective for expanding and maintaining expansion of small pupils in cataract surgery. The increase in postoperative pupil diameter is clinically diminutive and can most likely be attributed to preexisting pathologies affecting pupil innervation. Further large-scale studies are required to support the present findings.

Holistic ultrasound in trauma: An update.

PubMed

Saranteas, Theodosios; Mavrogenis, Andreas F

2016-10-01

Holistic ultrasound is a total body examination using an ultrasound device aiming to achieve immediate patient care and decision making. In the setting of trauma, it is one of the most fundamental components of care of the injured patients. Ground-breaking imaging software allows physicians to examine various organs thoroughly, recognize imaging signs early, and potentially foresee the onset or the possible outcome of certain types of injuries. Holistic ultrasound can be performed on a routine basis at the bedside of the patients, at admission and during the perioperative period. Trauma care physicians should be aware of the diagnostic and guidance benefits of ultrasound and should receive appropriate training for the optimal management of their patients. In this paper, the findings of holistic ultrasound in trauma patients are presented, with emphasis on the lungs, heart, cerebral circulation, abdomen, and airway. Additionally, the benefits of ultrasound imaging in interventional anaesthesia techniques such as ultrasound-guided peripheral nerve blocks and central vein catheterization are described. Copyright © 2016 Elsevier Ltd. All rights reserved.

A flexible ultrasound transducer array with micro-machined bulk PZT.

PubMed

Wang, Zhe; Xue, Qing-Tang; Chen, Yuan-Quan; Shu, Yi; Tian, He; Yang, Yi; Xie, Dan; Luo, Jian-Wen; Ren, Tian-Ling

2015-01-23

This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

Ultrasound: biological effects and industrial hygiene concerns.

PubMed

Wiernicki, C; Karoly, W J

1985-09-01

Due to the increased use of high intensity ultrasonic devices, there is now a greater risk of worker exposure to ultrasonic radiation than there was in the past. Exposure to high power ultrasound may produce adverse biological effects. High power ultrasound, characterized by high intensity outputs at frequencies of 20-100 kHz, has a wide range of applications throughout industry. Future applications may involve equipment with higher energy outputs. Contact ultrasound, i.e., no airspace between the energy source and the biological tissue, is significantly more hazardous than exposure to airborne ultrasound because air transmits less than one percent of the energy. This paper discusses biological effects associated with overexposure to ultrasound, exposure standards proposed for airborne and contact ultrasound, industrial hygiene controls that can be employed to minimize exposure, and the instrumentation that is required for evaluating exposures.

Biological effects of low frequency high intensity ultrasound application on ex vivo human adipose tissue.

PubMed

Palumbo, P; Cinque, B; Miconi, G; La Torre, C; Zoccali, G; Vrentzos, N; Vitale, A R; Leocata, P; Lombardi, D; Lorenzo, C; D'Angelo, B; Macchiarelli, G; Cimini, A; Cifone, M G; Giuliani, M

2011-01-01

In the present work the effects of a new low frequency, high intensity ultrasound technology on human adipose tissue ex vivo were studied. In particular, we investigated the effects of both external and surgical ultrasound-irradiation (10 min) by evaluating, other than sample weight loss and fat release, also histological architecture alteration as well apoptosis induction. The influence of saline buffer tissue-infiltration on the effects of ultrasound irradiation was also examined. The results suggest that, in our experimental conditions, both transcutaneous and surgical ultrasound exposure caused a significant weight loss and fat release. This effect was more relevant when the ultrasound intensity was set at 100 % (~2.5 W/cm², for external device; ~19-21 W/cm2, for surgical device) compared to 70 % (~1.8 W/cm² for external device; ~13-14 W/cm2 for surgical device). Of note, the effectiveness of ultrasound was much higher when the tissue samples were previously infiltrated with saline buffer, in accordance with the knowledge that ultrasonic waves in aqueous solution better propagate with a consequently more efficient cavitation process. Moreover, the overall effects of ultrasound irradiation did not appear immediately after treatment but persisted over time, being significantly more relevant at 18 h from the end of ultrasound irradiation. Evaluation of histological characteristics of ultrasound-irradiated samples showed a clear alteration of adipose tissue architecture as well a prominent destruction of collagen fibers which were dependent on ultrasound intensity and most relevant in saline buffer-infiltrated samples. The structural changes of collagen bundles present between the lobules of fat cells were confirmed through scanning electron microscopy (SEM) which clearly demonstrated how ultrasound exposure induced a drastic reduction in the compactness of the adipose connective tissue and an irregular arrangement of the fibers with a consequent alteration in

Eye wash water flow direction study: an evaluation of the effectiveness of eye wash devices with opposite directional water flow.

PubMed

Fogt, Jennifer S; Jones-Jordan, Lisa A; Barr, Joseph T

2018-01-01

New designs of eye wash stations have been developed in which the direction of water flow from the fountain has been reversed, with two water streams originating nasally in both eyes and flowing toward the temporal side of each eye. No study has been done to determine the ideal direction of water flow coming from the eye wash in relation to the eye. Ophthalmic eye examinations were conducted before and after the use of two eye wash stations with opposite water flow directionality. Fluorescein was instilled in both eyes before using an eye wash to measure the effectiveness of the water flow. Subjects were surveyed upon their experiences using the eye washes. Ophthalmic examination found no significant difference in the efficacy of the eye washes with nasal-to-temporal water flow when compared to temporal-to-nasal water flow direction.

Eye-Safe Lidar

NASA Technical Reports Server (NTRS)

Byer, Robert L.

1989-01-01

Laser infrared radar (lidar) undergoing development harmless to human eyes, consists almost entirely of solid-state components, and offers high range resolution. Operates at wavelength of about 2 micrometers. If radiation from such device strikes eye, almost completely absorbed by cornea without causing damage, even if aimed directly at eye. Continuous-wave light from laser oscillator amplified and modulated for transmission from telescope. Small portion of output of oscillator fed to single-mode fiber coupler, where mixed with return pulses. Intended for remote Doppler measurements of winds and differential-absorption measurements of concentrations of gases in atmosphere.

Tracked 3D ultrasound in radio-frequency liver ablation

NASA Astrophysics Data System (ADS)

Boctor, Emad M.; Fichtinger, Gabor; Taylor, Russell H.; Choti, Michael A.

2003-05-01

Recent studies have shown that radio frequency (RF) ablation is a simple, safe and potentially effective treatment for selected patients with liver metastases. Despite all recent therapeutic advancements, however, intra-procedural target localization and precise and consistent placement of the tissue ablator device are still unsolved problems. Various imaging modalities, including ultrasound (US) and computed tomography (CT) have been tried as guidance modalities. Transcutaneous US imaging, due to its real-time nature, may be beneficial in many cases, but unfortunately, fails to adequately visualize the tumor in many cases. Intraoperative or laparoscopic US, on the other hand, provides improved visualization and target imaging. This paper describes a system for computer-assisted RF ablation of liver tumors, combining navigational tracking of a conventional imaging ultrasound probe to produce 3D ultrasound imaging with a tracked RF ablation device supported by a passive mechanical arm and spatially registered to the ultrasound volume.

Comparison of postoperative refractive outcomes: IOLMaster® versus immersion ultrasound.

PubMed

Whang, Woong-Joo; Jung, Byung-Ju; Oh, Tae-Hoon; Byun, Yong-Soo; Joo, Choun-Ki

2012-01-01

To compare the postoperative refractive outcomes between IOLMaster biometry (Carl Zeiss Meditec, Inc., Dublin, CA) and immersion ultrasound biometry for axial length measurements. Refractive outcomes in 354 eyes were compared using the IOLMaster and the immersion ultrasound biometry. Predicted refraction was determined using manual keratometry and the SRK-T formula with personalized A-constant. The axial lengths measured using the IOLMaster and immersion ultrasound were 24.49 ± 2.11 and 24.46 ± 2.11 mm, respectively, and the difference was significant (P < .05). The mean errors were 0.000 ± 0.578 D with the IOLMaster, and 0.000 ± 0.599 D with the immersion ultrasound, but the difference was not significant. The mean absolute error was smaller with the IOLMaster than with immersion ultrasound (0.463 ± 0.341 vs 0.479 ± 0.359 D), but the difference was not significant. IOLMaster biometry yields highly accurate results in cataract surgery. However, if the IOLMaster is unavailable, immersion ultrasound biometry with personalized intraocular lens constants is an acceptable alternative. Copyright 2012, SLACK Incorporated.

Thermo-Acoustic Ultrasound for Detection of RF-Induced Device Lead Heating in MRI.

PubMed

Dixit, Neerav; Stang, Pascal P; Pauly, John M; Scott, Greig C

2018-02-01

Patients who have implanted medical devices with long conductive leads are often restricted from receiving MRI scans due to the danger of RF-induced heating near the lead tips. Phantom studies have shown that this heating varies significantly on a case-by-case basis, indicating that many patients with implanted devices can receive clinically useful MRI scans without harm. However, the difficulty of predicting RF-induced lead tip heating prior to scanning prevents numerous implant recipients from being scanned. Here, we demonstrate that thermo-acoustic ultrasound (TAUS) has the potential to be utilized for a pre-scan procedure assessing the risk of RF-induced lead tip heating in MRI. A system was developed to detect TAUS signals by four different TAUS acquisition methods. We then integrated this system with an MRI scanner and detected a peak in RF power absorption near the tip of a model lead when transmitting from the scanner's body coil. We also developed and experimentally validated simulations to characterize the thermo-acoustic signal generated near lead tips. These results indicate that TAUS is a promising method for assessing RF implant safety, and with further development, a TAUS pre-scan could allow many more patients to have access to MRI scans of significant clinical value.

Effectiveness of Existing Eye Safety Legislation in Arizona.

ERIC Educational Resources Information Center

Gillaspy, Roy Eugene

This study was designed to ascertain the current practices of eye safety in Arizona high school industrial education laboratories, including the enforcement of eye safety legislation, use of eye protection devices, how the eye ware meets the American National Standards Institute specifications, and the teachers' interpretations of the existing eye…

Optical Micromachined Ultrasound Transducers (OMUT)-- A New Approach for High Frequency Ultrasound Imaging

NASA Astrophysics Data System (ADS)

Tadayon, Mohammad Amin

Piezoelectric technology is the backbone of most medical ultrasound imaging arrays, however, in scaling the technology to sizes required for high frequency operation (> 20 MHz), it encounters substantial difficulties in fabrication and signal transduction efficiency. These limitations particularly affect the design of intravascular ultrasound (IVUS) imaging probes whose operating frequency can approach 60 MHz. Optical technology has been proposed and investigated for several decades as an alternative approach for high frequency ultrasound transducers. However, to apply this promising technology in guiding clinical operations such as in interventional cardiology, brain surgery, and laparoscopic surgery further raise in the sensitivity is required. Here, in order to achieve the required sensitivity for an intravascular ultrasound imaging probe, we introduce design changes making use of alternative receiver mechanisms. First, we present an air cavity detector that makes use of a polymer membrane for increased mechanical deflection. We have also significantly raised the thin film detector sensitivity by improving its optical characteristics. This can be achieved by inducing a refractive index feature inside the Fabry-Perot resonator that simply creates a waveguide between the two mirrors. This approach eliminates the loss in energy due to diffraction in the cavity, and therefore the Q-factor is only limited by mirror loss and absorption. To demonstrate this optical improvements, a waveguide Fabry-Perot resonator has been fabricated consisting of two dielectric Bragg reflectors with a layer of photosensitive polymer between them. The measured finesse of the fabricated resonator was 692, and the Q-factor was 55000. The fabrication process of this device has been modified to fabricate an ultrasonically testable waveguide Fabry-Perot resonator. By applying this method, we have achieved a noise equivalent pressure of 178 Pa over a bandwidth of 28 MHz or 0.03 Pa/Hz1/2 which

Evaluation of a recently developed noncontact specular microscope in comparison with conventional pachymetry devices.

PubMed

Módis, László; Szalai, Eszter; Németh, Gábor; Berta, András

2010-01-01

The study was conducted to assess the central corneal thickness (CCT) of the healthy cornea with a recently developed noncontact specular microscope (EM-3000; Tomey) and compare the results with those measured with a contact specular microscope and an ultrasound pachymeter. Agreement between measurements taken by 2 investigators was also studied. The right eyes of 41 healthy individuals who had negative history of contact lens wear, ophthalmic disease, or ocular surgery were examined. The CCT was determined sequentially with a noncontact specular microscope, a contact specular microscope (EM-1000; Tomey), and an ultrasound pachymeter (AL-2000; Tomey). Each evaluation with the specular microscopes was performed by 2 independent operators. A significant difference was detected in pachymetry measurements among the 3 instruments (p=0.01; analysis of variance). The mean CCT values were lower measured with the ultrasound pachymeter (537+/-30 microm) than the contact endothelial microscope (543+/-37 microm, p=0.17, Student t-test) and the noncontact microscope (549+/-33 microm, p<0.0001) (operator 1). There was no statistically significant difference in CCT measurements between the 2 endothelial microscopes (p=0.19). We found significant correlations (p<0.0001) in thickness measurements between each pair of instruments (r=0.91, noncontact microscopy and ultrasound pachymetry; r=0.74, noncontact and contact microscopy; r=0.72, contact microscopy and ultrasound pachymetry; Spearman rank correlation). The strong correlations among the 3 pachymetry devices suggest that the tested instruments provide reliable measurements; however, they cannot be used interchangeably.

High frequency ultrasound: a new frontier for ultrasound.

PubMed

Shung, K; Cannata, Jonathan; Qifa Zhou, Member; Lee, Jungwoo

2009-01-01

High frequency ultrasonic imaging is considered by many to be the next frontier in ultrasonic imaging because higher frequencies yield much improved spatial resolution by sacrificing the depth of penetration. It has many clinical applications including visualizing blood vessel wall, anterior segments of the eye and skin. Another application is small animal imaging. Ultrasound is especially attractive in imaging the heart of a small animal like mouse which has a size in the mm range and a heart beat rate faster than 600 BPM. A majority of current commercial high frequency scanners often termed "ultrasonic backscatter microscope or UBM" acquire images by scanning single element transducers at frequencies between 50 to 80 MHz with a frame rate lower than 40 frames/s, making them less suitable for this application. High frequency linear arrays and linear array based ultrasonic imaging systems at frequencies higher than 30 MHz are being developed. The engineering of such arrays and development of high frequency imaging systems has been proven to be highly challenging. High frequency ultrasound may find other significant biomedical applications. The development of acoustic tweezers for manipulating microparticles is such an example.

Eye point-of-regard system

NASA Technical Reports Server (NTRS)

Jex, H. R.

1971-01-01

System measures intersection of line of sight and eye point of regard /EPR/ for a human operator in visual scanning system. Device measures two head to reference angles with EPR system and adds them with eye to head angles, yielding a dc signal proportional to picture plane coordinates.

Fluid Mixing in the Eye Under Rapid Eye Movement

NASA Astrophysics Data System (ADS)

Huang, Jinglin; Gharib, Morteza

2017-11-01

Drug injection is an important technique in certain treatments of eye diseases. The efficacy of chemical mixing plays an important role in determining pharmacokinetics of injected drugs. In this study, we build a device to study the chemical mixing behavior in a spherical structure. The mixing process is visualized and analyzed qualitatively. We hope to understand the chemical convection and diffusion behaviors in correlation with controlled rapid mechanical movements. The results will have potential applications in treatment of eye diseases. Resnick Institute at Caltech.

Noninvasive measurement of wave speed of porcine cornea in ex vivo porcine eyes for various intraocular pressures.

PubMed

Zhou, Boran; Sit, Arthur J; Zhang, Xiaoming

2017-11-01

The objective of this study was to extend an ultrasound surface wave elastography (USWE) technique for noninvasive measurement of ocular tissue elastic properties. In particular, we aim to establish the relationship between the wave speed of cornea and the intraocular pressure (IOP). Normal ranges of IOP are between 12 and 22mmHg. Ex vivo porcine eye balls were used in this research. The porcine eye ball was supported by the gelatin phantom in a testing container. Some water was pour into the container for the ultrasound measurement. A local harmonic vibration was generated on the side of the eye ball. An ultrasound probe was used to measure the wave propagation in the cornea noninvasively. A 25 gauge butterfly needle was inserted into the vitreous humor of the eye ball under the ultrasound imaging guidance. The needle was connected to a syringe. The IOP was obtained by the water height difference between the water level in the syringe and the water level in the testing container. The IOP was adjusted between 5mmHg and 30mmHg with a 5mmHg interval. The wave speed was measured at each IOP for three frequencies of 100, 150 and 200Hz. Finite element method (FEM) was used to simulate the wave propagation in the corneal according to our experimental setup. A linear viscoelastic FEM model was used to compare the experimental data. Both the experiments and the FEM analyses showed that the wave speed of cornea increased with IOP. Copyright © 2017 Elsevier B.V. All rights reserved.

Staying away from the optic nerve: a formula for modifying glaucoma drainage device surgery in pediatric and other small eyes.

PubMed

Margeta, Milica A; Kuo, Anthony N; Proia, Alan D; Freedman, Sharon F

2017-02-01

To provide guidelines for safe implantation of glaucoma drainage devices (GDDs) in small and pediatric eyes to avoid contact between the optic nerve (ON) and the posterior edge of the GDD plate. We developed a formula for calculating limbus-to-ON distance to estimate the available "real estate" for GDD placement in small eyes. The formula was validated using eyes of pediatric decedents undergoing clinical autopsy, with axial lengths (AL) of 15-24 mm. For each autopsy eye, we measured AL, anterior chamber depth, corneal diameter, and limbus-to-ON distances for the four eye quadrants. The main outcome measure was the degree of agreement between measured and calculated limbus-to-ON distances. A total of 15 autopsy eyes were divided into derivation (n = 10) and validation (n = 5) groups. A formula was derived to estimate superotemporal limbus-to-ON distance (D ST ) using AL and corneal diameter data. Linear regression showed excellent correlation between the measured D ST and AL (R 2  = 0.98). There was excellent agreement between measured and calculated limbus-to-ON values for all four eye quadrants (R 2 range, 0.92-0.98). Our formula accurately predicts limbus-to-ON distances across a wide range of clinically relevant ALs. Based on this information, GDD surgery in small eyes can be adjusted by positioning the GDD closer to the limbus or by trimming the posterior edge of the GDD plate. To our knowledge, this is the first set of guidelines developed to promote safe implantation of GDDs in small eyes. Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

A new approach for the screening of carotid lesions: a 'fast-track' method with the use of new generation hand-held ultrasound devices.

PubMed

Aboyans, V; Lacroix, P; Jeannicot, A; Guilloux, J; Bertin, F; Laskar, M

2004-09-01

We assessed the usefulness of fast-track neck sonography with a new-generation hand-held ultrasound scanner in the detection of > or =60% carotid stenosis. Patients with a past history of atherosclerotic disease or presence of risk factors were enrolled. All had fast-track carotid screening with a hand-held ultrasound scanner. Initial assessment was performed with our quick imaging protocol. A second examiner performed a conventional complete carotid duplex as gold-standard. We enrolled 197 consecutive patients with a mean age of 67 years (range 35-94). A carotid stenosis >60% was detected in 13 cases (6%). The sensitivity, specificity, positive and negative predictive value of fast-track sonography was 100%, 64%, 17% and 100%, respectively. Concomitant power Doppler imaging during the fast-track method did not improve accuracy. The use of a fast-track method with a hand-held ultrasound device can reduce the number of unnecessary carotid Duplex and enhance the screening efficiency without missing significant carotid stenoses.

Simulation and training of ultrasound supported anaesthesia: a low-cost approach

NASA Astrophysics Data System (ADS)

Schaaf, T.; Lamontain, M.; Hilpert, J.; Schilling, F.; Tolxdorff, T.

2010-03-01

The use of ultrasound imaging technology during techniques of peripheral nerve blockade offers several clinical benefits. Here we report on a new method to educate residents in ultrasound-guided regional anesthesia. The daily challenge for the anesthesiologists is the 3D angle-depending handling of the stimulation needle and the ultrasound probe while watching the 2D ultrasound image on the monitor. Purpose: Our approach describes how a computer-aided simulation and training set for ultrasound-guided regional anesthesia could be built based on wireless low-cost devices and an interactive simulation of a 2D ultrasound image. For training purposes the injection needle and the ultrasound probe are replaced by wireless Bluetooth-connected 3D tracking devices, which are embedded in WII-mote controllers (Nintendo-Brand). In correlation to the tracked 3D positions of the needle and transducer models the visibility and position of the needle should be simulated in the 2D generated ultrasound image. Conclusion: In future, this tracking and visualization software module could be integrated in a more complex training set, where complex injection paths could be trained based on a 3D segmented model and the training results could be part of a curricular e-learning module.

Implementation of a rotational ultrasound biomicroscopy system equipped with a high-frequency angled needle transducer--ex vivo ultrasound imaging of porcine ocular posterior tissues.

PubMed

Bok, Tae-Hoon; Kim, Juho; Bae, Jinho; Lee, Chong Hyun; Paeng, Dong-Guk

2014-09-24

The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM) system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270°~330° and at a distance range of 6~7 mm, whereas the tissues of the other eye were observed in relative angle range of 160°~220° and at a distance range of 7.5~9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system.

[Efficacy and problems of bladder volume measurement using portable three dimensional ultrasound scanning device--in particular, on measuring bladder volume lower than 100ml].

PubMed

Oh-Oka, Hitoshi; Nose, Ryuichiro

2005-09-01

Using a portable three dimensional ultrasound scanning device (The Bladder Scan BVI6100, Diagnostic Ultrasound Corporation), we examined measured values of bladder volume, especially focusing on volume lower than 100 ml. A total of 100 patients (male: 66, female: 34) were enrolled in the study. We made a comparison study between the measured value (the average of three measurements of bladder urine volume after a trial in male and female modes) using BVI6100, and the actual measured value of the sample obtained by urethral catheterization in each patient. We examined the factors which could increase the error rate. We also introduced the effective techniques to reduce measurement errors. The actual measured values in all patients correlated well with the average value of three measurements after a trial in a male mode of the BVI6100. The correlation coefficient was 0.887, the error rate was--4.6 +/- 24.5%, and the average coefficient of variation was 15.2. It was observed that the measurement result using the BVI6100 is influenced by patient side factors (extracted edges between bladder wall and urine, thickened bladder wall, irregular bladder wall, flattened rate of bladder, mistaking prostate for bladder in male, mistaking bladder for uterus in a female mode, etc.) or examiner side factors (angle between BVI and abdominal wall, compatibility between abdominal wall and ultrasound probe, controlling deflection while using probe, etc). When appropriate patients are chosen and proper measurement is performed, BVI6100 provides significantly higher accuracy in determining bladder volume, compared with existing abdominal ultrasound methods. BVI6100 is a convenient and extremely effective device also for the measurement of bladder urine over 100 ml.

Cognitive load predicts point-of-care ultrasound simulator performance.

PubMed

Aldekhyl, Sara; Cavalcanti, Rodrigo B; Naismith, Laura M

2018-02-01

The ability to maintain good performance with low cognitive load is an important marker of expertise. Incorporating cognitive load measurements in the context of simulation training may help to inform judgements of competence. This exploratory study investigated relationships between demographic markers of expertise, cognitive load measures, and simulator performance in the context of point-of-care ultrasonography. Twenty-nine medical trainees and clinicians at the University of Toronto with a range of clinical ultrasound experience were recruited. Participants answered a demographic questionnaire then used an ultrasound simulator to perform targeted scanning tasks based on clinical vignettes. Participants were scored on their ability to both acquire and interpret ultrasound images. Cognitive load measures included participant self-report, eye-based physiological indices, and behavioural measures. Data were analyzed using a multilevel linear modelling approach, wherein observations were clustered by participants. Experienced participants outperformed novice participants on ultrasound image acquisition. Ultrasound image interpretation was comparable between the two groups. Ultrasound image acquisition performance was predicted by level of training, prior ultrasound training, and cognitive load. There was significant convergence between cognitive load measurement techniques. A marginal model of ultrasound image acquisition performance including prior ultrasound training and cognitive load as fixed effects provided the best overall fit for the observed data. In this proof-of-principle study, the combination of demographic and cognitive load measures provided more sensitive metrics to predict ultrasound simulator performance. Performance assessments which include cognitive load can help differentiate between levels of expertise in simulation environments, and may serve as better predictors of skill transfer to clinical practice.

Antenatal diagnosis of anophthalmia by three-dimensional ultrasound: a novel application of the reverse face view.

PubMed

Wong, H S; Parker, S; Tait, J; Pringle, K C

2008-07-01

The prenatal diagnosis of anophthalmia can be made on the demonstration of absent eye globe and lens on the affected side(s) on two-dimensional ultrasound examination, but when the fetal head position is unfavorable three-dimensional (3D) ultrasound may reveal additional diagnostic sonographic features, including sunken eyelids and small or hypoplastic orbit on the affected side(s). We present two cases of isolated anophthalmia diagnosed on prenatal ultrasound examination in which 3D ultrasound provided additional diagnostic information. The reverse face view provides valuable information about the orbits and the eyeballs for prenatal diagnosis and assessment of anophthalmia.

Development of a Mechanical Scanning Device With High-Frequency Ultrasound Transducer for Ultrasonic Capsule Endoscopy.

PubMed

Wang, Xingying; Seetohul, Vipin; Chen, Ruimin; Zhang, Zhiqiang; Qian, Ming; Shi, Zhehao; Yang, Ge; Mu, Peitian; Wang, Congzhi; Huang, Zhihong; Zhou, Qifa; Zheng, Hairong; Cochran, Sandy; Qiu, Weibao

2017-09-01

Wireless capsule endoscopy has opened a new era by enabling remote diagnostic assessment of the gastrointestinal tract in a painless procedure. Video capsule endoscopy is currently commercially available worldwide. However, it is limited to visualization of superficial tissue. Ultrasound (US) imaging is a complementary solution as it is capable of acquiring transmural information from the tissue wall. This paper presents a mechanical scanning device incorporating a high-frequency transducer specifically as a proof of concept for US capsule endoscopy (USCE), providing information that may usefully assist future research. A rotary solenoid-coil-based motor was employed to rotate the US transducer with sectional electronic control. A set of gears was used to convert the sectional rotation to circular rotation. A single-element focused US transducer with 39-MHz center frequency was used for high-resolution US imaging, connected to an imaging platform for pulse generation and image processing. Key parameters of US imaging for USCE applications were evaluated. Wire phantom imaging and tissue phantom imaging have been conducted to evaluate the performance of the proposed method. A porcine small intestine specimen was also used for imaging evaluation in vitro. Test results demonstrate that the proposed device and rotation mechanism are able to offer good image resolution ( [Formula: see text]) of the lumen wall, and they, therefore, offer a viable basis for the fabrication of a USCE device.

Eye vision system using programmable micro-optics and micro-electronics

NASA Astrophysics Data System (ADS)

Riza, Nabeel A.; Amin, M. Junaid; Riza, Mehdi N.

2014-02-01

Proposed is a novel eye vision system that combines the use of advanced micro-optic and microelectronic technologies that includes programmable micro-optic devices, pico-projectors, Radio Frequency (RF) and optical wireless communication and control links, energy harvesting and storage devices and remote wireless energy transfer capabilities. This portable light weight system can measure eye refractive powers, optimize light conditions for the eye under test, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. Described is the basic design of the proposed system and its first stage system experimental results for vision spherical lens refractive error correction.

Improvement of design of a surgical interface using an eye tracking device

PubMed Central

2014-01-01

Background Surgical interfaces are used for helping surgeons in interpretation and quantification of the patient information, and for the presentation of an integrated workflow where all available data are combined to enable optimal treatments. Human factors research provides a systematic approach to design user interfaces with safety, accuracy, satisfaction and comfort. One of the human factors research called user-centered design approach is used to develop a surgical interface for kidney tumor cryoablation. An eye tracking device is used to obtain the best configuration of the developed surgical interface. Methods Surgical interface for kidney tumor cryoablation has been developed considering the four phases of user-centered design approach, which are analysis, design, implementation and deployment. Possible configurations of the surgical interface, which comprise various combinations of menu-based command controls, visual display of multi-modal medical images, 2D and 3D models of the surgical environment, graphical or tabulated information, visual alerts, etc., has been developed. Experiments of a simulated cryoablation of a tumor task have been performed with surgeons to evaluate the proposed surgical interface. Fixation durations and number of fixations at informative regions of the surgical interface have been analyzed, and these data are used to modify the surgical interface. Results Eye movement data has shown that participants concentrated their attention on informative regions more when the number of displayed Computer Tomography (CT) images has been reduced. Additionally, the time required to complete the kidney tumor cryoablation task by the participants had been decreased with the reduced number of CT images. Furthermore, the fixation durations obtained after the revision of the surgical interface are very close to what is observed in visual search and natural scene perception studies suggesting more efficient and comfortable interaction with the

Improvement of design of a surgical interface using an eye tracking device.

PubMed

Erol Barkana, Duygun; Açık, Alper; Duru, Dilek Goksel; Duru, Adil Deniz

2014-05-07

Surgical interfaces are used for helping surgeons in interpretation and quantification of the patient information, and for the presentation of an integrated workflow where all available data are combined to enable optimal treatments. Human factors research provides a systematic approach to design user interfaces with safety, accuracy, satisfaction and comfort. One of the human factors research called user-centered design approach is used to develop a surgical interface for kidney tumor cryoablation. An eye tracking device is used to obtain the best configuration of the developed surgical interface. Surgical interface for kidney tumor cryoablation has been developed considering the four phases of user-centered design approach, which are analysis, design, implementation and deployment. Possible configurations of the surgical interface, which comprise various combinations of menu-based command controls, visual display of multi-modal medical images, 2D and 3D models of the surgical environment, graphical or tabulated information, visual alerts, etc., has been developed. Experiments of a simulated cryoablation of a tumor task have been performed with surgeons to evaluate the proposed surgical interface. Fixation durations and number of fixations at informative regions of the surgical interface have been analyzed, and these data are used to modify the surgical interface. Eye movement data has shown that participants concentrated their attention on informative regions more when the number of displayed Computer Tomography (CT) images has been reduced. Additionally, the time required to complete the kidney tumor cryoablation task by the participants had been decreased with the reduced number of CT images. Furthermore, the fixation durations obtained after the revision of the surgical interface are very close to what is observed in visual search and natural scene perception studies suggesting more efficient and comfortable interaction with the surgical interface. The

Evaluation of iridociliary and lenticular elasticity using shear-wave elastography in rabbit eyes.

PubMed

Detorakis, Efstathios T; Drakonaki, Eleni E; Ginis, Harilaos; Karyotakis, Nikolaos; Pallikaris, Ioannis G

2014-01-01

A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine. Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer. Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity. Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.

Design of a Subtarsal Ultrasonic Transducer for Mild Hyperthermia Treatment of Dry Eye Disease.

PubMed

Hynes, Michael B; Bujak, Matthew C; Chérin, Emmanuel; Sade, Shachar; Foster, F Stuart

2016-01-01

Dry eye disease is a disorder of the ocular surface that causes pain and low vision in a significant portion of the adult population. A common cause is obstructive Meibomian gland dysfunction, whereby the Meibomian glands secrete abnormal meibum with a melting point elevated by 3°C-4°C; hence, hyperthermia is the typical treatment. A design is proposed for an ultrasound hyperthermia device made of a transducer contained inside a contact lens with an internal air gap. The transducer heats the posterior of the tarsus, and the air gap provides an air backing to the transducer, preventing direct heating of the cornea. A prototype device was built, and hyperthermia experiments were performed on a porcine subject in vivo. A therapeutic temperature rise of 5°C-7°C was achievable in 10-15 min. The temperature of the cornea did not rise more than 2°C during any of the experiments. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

An ergonomic, instrumented ultrasound probe for 6-axis force/torque measurement.

PubMed

Gilbertson, Matthew W; Anthony, Brian W

2013-01-01

An ergonomic, instrumented ultrasound probe has been developed for medical imaging applications. The device, which fits compactly in the hand of sonographers and permits rapid attachment & removal of the ultrasound probe, measures ultrasound probe-to-patient contact forces and torques in all six axes. The device was used to measure contact forces and torques applied by ten professional sonographers on five patients during thirty-six abdominal exams. Of the three contact forces, those applied along the probe axis were found to be largest, averaging 7.0N. Measurement noise was quantified for each axis, and found to be small compared with the axial force. Understanding the range of forces applied during ultrasound imaging enables the design of more accurate robotic imaging systems and could also improve understanding of the correlation between contact force and sonographer fatigue and injury.

Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

PubMed Central

Ramasubramanian, Viswanathan; Glasser, Adrian

2015-01-01

PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly (P < .0001) linearly correlated with accommodative stimulus amplitudes. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD 0.0176 mm, lens thickness 0.0294 mm, anterior lens radius of curvature 0.3350 mm, posterior lens radius of curvature 0.1580 mm, and anterior segment length 0.0340 mm). The mean difference between the A-scan and UBM measurements was −0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. PMID:25804579

Is it Time to Replace Physical Examination with a Hand-Held Ultrasound Device?

PubMed Central

Kaul, Sanjiv

2014-01-01

Attempts at using physical examination (PE) go back centuries, with inspection, palpation, and percussion being the mainstay of this approach until 2 centuries ago when the stethoscope was invented and auscultation became probably the most important element of PE for patients with known or suspected cardiovascular disease (CVD). Despite its several limitations, PE is still used, sometimes as the only means, of evaluating and following patients with CVD. In this paper I shall argue for the substitution of this inaccurate and archaic approach by direct visualization of the heart using a hand-held ultrasound (HHU) device. I am not in any way suggesting the substitution of a comprehensive echocardiographic examination by an expert sonographer/echocardiographer by HHU in patients with significant CVD. Instead, I am arguing for the replacement of PE for evaluation of the heart at the point of care as well as at the bedside, simply because HHU is more accurate and provides more meaningful information. PMID:28465916

Is it Time to Replace Physical Examination with a Hand-Held Ultrasound Device?

PubMed

Kaul, Sanjiv

2014-01-01

Attempts at using physical examination (PE) go back centuries, with inspection, palpation, and percussion being the mainstay of this approach until 2 centuries ago when the stethoscope was invented and auscultation became probably the most important element of PE for patients with known or suspected cardiovascular disease (CVD). Despite its several limitations, PE is still used, sometimes as the only means, of evaluating and following patients with CVD. In this paper I shall argue for the substitution of this inaccurate and archaic approach by direct visualization of the heart using a hand-held ultrasound (HHU) device. I am not in any way suggesting the substitution of a comprehensive echocardiographic examination by an expert sonographer/echocardiographer by HHU in patients with significant CVD. Instead, I am arguing for the replacement of PE for evaluation of the heart at the point of care as well as at the bedside, simply because HHU is more accurate and provides more meaningful information.

Agreement between gonioscopy and ultrasound biomicroscopy in detecting iridotrabecular apposition.

PubMed

Barkana, Yaniv; Dorairaj, Syril K; Gerber, Yariv; Liebmann, Jeffrey M; Ritch, Robert

2007-10-01

To assess the agreement between findings obtained at dark-room gonioscopy and ultrasound biomicroscopy (UBM) in the diagnosis of iridotrabecular apposition in light and dark conditions. We enrolled patients with appositional angle closure at dark-room gonioscopy performed using a 1-mm slitlamp beam that did not cross the pupil. Ultrasound biomicroscopic images were acquired in normal room light and subsequently with all room lights off. Images were evaluated for the presence or absence of iris-cornea contact. The angle opening distance at 500 microm was calculated. Iridotrabecular apposition in at least 1 angle quadrant was demonstrated in all 18 eyes at dark-room gonioscopy, 17 eyes (94%) at dark-room UBM, and only 10 eyes (56%) at UBM in room light. Of 18 superior angles that were appositionally closed at dark-room gonioscopy, apposition was demonstrated on UBM images in 16 (89%) in a dark room but only 6 (33%) in room light. Angle opening distance was less during dark-room gonioscopy in all but the nasal quadrant. We found high agreement between gonioscopy and UBM when both are performed in a completely dark room. Our findings support the recommendation that, in routine clinical practice, gonioscopy be performed in a dark room to avoid misdiagnosis of treatable iridotrabecular apposition.

Management of digital eye strain.

PubMed

Coles-Brennan, Chantal; Sulley, Anna; Young, Graeme

2018-05-23

Digital eye strain, an emerging public health issue, is a condition characterised by visual disturbance and/or ocular discomfort related to the use of digital devices and resulting from a range of stresses on the ocular environment. This review aims to provide an overview of the extensive literature on digital eye strain research with particular reference to the clinical management of symptoms. As many as 90 per cent of digital device users experience symptoms of digital eye strain. Many studies suggest that the following factors are associated with digital eye strain: uncorrected refractive error (including presbyopia), accommodative and vergence anomalies, altered blinking pattern (reduced rate and incomplete blinking), excessive exposure to intense light, closer working distance, and smaller font size. Since a symptom may be caused by one or more factors, a holistic approach should be adopted. The following management strategies have been suggested: (i) appropriate correction of refractive error, including astigmatism and presbyopia; (ii) management of vergence anomalies, with the aim of inducing or leaving a small amount of heterophoria (~1.5 Δ Exo); (iii) blinking exercise/training to maintain normal blinking pattern; (iv) use of lubricating eye drops (artificial tears) to help alleviate dry eye-related symptoms; (v) contact lenses with enhanced comfort, particularly at end-of-day and in challenging environments; (vi) prescription of colour filters in all vision correction options, especially blue light-absorbing filters; and (vii) management of accommodative anomalies. Prevention is the main strategy for management of digital eye strain, which involves: (i) ensuring an ergonomic work environment and practice (through patient education and the implementation of ergonomic workplace policies); and (ii) visual examination and eye care to treat visual disorders. Special consideration is needed for people at a high risk of digital eye strain, such as computer

Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices.

PubMed

Sano, Ichiya; Tanito, Masaki; Uchida, Koji; Katsube, Takashi; Kitagaki, Hajime; Ohira, Akihiro

2015-01-01

To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs) using magnetic resonance imaging (MRI) and the effects of various factors on postoperative intraocular pressure (IOP). This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years) who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]). Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured. In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182) and bleb height (r = -0.3954, P = 0.0412). The postoperative IOP was significantly (P = 0.0026) lower in BGI-implanted eyes (12.2±0.7 mmHg) than AGV-implanted eyes (16.7±1.2 mmHg); bleb volume was significantly (P = 0.0093) larger in BGI-implanted eyes (478.8±84.2 mm3) than AGV-implanted eyes (161.1±52.3 mm3). Other parameters did not differ. The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long-tube GDDs.

High intensity focused ultrasound (HIFU).

PubMed

Barkin, Jack

2011-04-01

Curative treatments for localized prostate cancer, from least invasive to most invasive, include brachytherapy, cryosurgery, three-dimensional conformal radiation therapy, external beam radiation therapy, and radical prostatectomy. A patient with localized, low risk or intermediate risk prostate cancer who is diagnosed at an early age and receives one of these treatments has only an approximately 50% chance of maintaining an undetectable prostate-specific antigen (PSA) level, good spontaneous erections, and total continence by 5 years after treatment. This article discusses transrectal high intensity focused ultrasound (HIFU) treatment of localized prostate cancer using the Sonablate 500 (Focus Surgery, Indianapolis, IN, USA) device, which the author has adopted in favor of the Ablatherm (EDAP, TMS S. A., Lyons, France) device, the other HIFU device approved for use in Canada. Characteristics of the ideal prostate cancer include stage T1-T2b, less than 40 cc in size, and with an anterior-posterior dimension of up to 35 mm high. The anterior zone of the prostate is treated before the posterior zone. The procedure involves 2 to 3 second bursts of ultrasound energy, followed by 3 second cooling cycles. In each treatment lesion, the physician achieves a temperature of 100 C at the focal point. The device allows for real-time visualization of tissue response following the delivery of ultrasound energy. HIFU is a minimally invasive, outpatient treatment for localized prostate cancer that provides similar short term and medium term cure rates and considerably less morbidity and side effects than other treatments. Although the effectiveness of HIFU has not yet been demonstrated in large, long term studies, this treatment option should be discussed with patients who have just been diagnosed with low risk or intermediate risk prostate cancer and desire aggressive, noninvasive, curative therapy, with potentially a lower incidence of side effects compared to conventional

Real-time registration of video with ultrasound using stereo disparity

NASA Astrophysics Data System (ADS)

Wang, Jihang; Horvath, Samantha; Stetten, George; Siegel, Mel; Galeotti, John

2012-02-01

Medical ultrasound typically deals with the interior of the patient, with the exterior left to the original medical imaging modality, direct human vision. For the human operator scanning the patient, the view of the external anatomy is essential for correctly locating the ultrasound probe on the body and making sense of the resulting ultrasound images in their proper anatomical context. The operator, after all, is not expected to perform the scan with his eyes shut. Over the past decade, our laboratory has developed a method of fusing these two information streams in the mind of the operator, the Sonic Flashlight, which uses a half silvered mirror and miniature display mounted on an ultrasound probe to produce a virtual image within the patient at its proper location. We are now interested in developing a similar data fusion approach within the ultrasound machine itself, by, in effect, giving vision to the transducer. Our embodiment of this concept consists of an ultrasound probe with two small video cameras mounted on it, with software capable of locating the surface of an ultrasound phantom using stereo disparity between the two video images. We report its first successful operation, demonstrating a 3D rendering of the phantom's surface with the ultrasound data superimposed at its correct relative location. Eventually, automated analysis of these registered data sets may permit the scanner and its associated computational apparatus to interpret the ultrasound data within its anatomical context, much as the human operator does today.

Simultaneous ultrasound and photoacoustics based flow cytometry

NASA Astrophysics Data System (ADS)

Gnyawali, Vaskar; Strohm, Eric M.; Tsai, Scott S. H.; Kolios, Michael C.

2018-04-01

We have developed a flow cytometer based on simultaneous detection of ultrasound and photoacoustic waves from individual particles/cells flowing in a microfluidic channel. Our polydimethylsiloxane (PDMS) based hydrodynamic 3-dimensional (3D) flow-focusing microfluidic device contains a cross-junction channel, a micro-needle (ID 100 μm and OD 200 μm) insert, and a 3D printed frame to hold and align a high frequency (center frequency 375 MHz) ultrasound transducer. The focused flow passes through a narrow focal zone with lateral and axial focal lengths of 6-8 μm and 15-20 μm, respectively. Both the lateral and axial alignments are achieved by screwing the transducer to the frame onto the PDMS device. Individual particles pass through an interrogation zone in the microfluidic channel with a collinearly aligned ultrasound transducer and a focused 532 nm wavelength laser beam. The particles are simultaneously insonified by high-frequency ultrasound and irradiated by a laser beam. The ultrasound backscatter and laser generated photoacoustic waves are detected for each passing particle. The backscattered ultrasound and photoacoustic signal are strongly dependent on the size, morphology, mechanical properties, and material properties of the flowing particles; these parameters can be extracted by analyzing unique features in the power spectrum of the signals. Frequencies less than 100 MHz do not have these unique spectral signatures. We show that we can reliably distinguish between different particles in a sample using the acoustic-based flow cytometer. This technique, when extended to biomedical applications, allows us to rapidly analyze the spectral signatures from individual single cells of a large cell population, with applications towards label-free detection and characterization of healthy and diseased cells.

Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

NASA Technical Reports Server (NTRS)

Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

1997-01-01

Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

29 CFR 1917.91 - Eye and face protection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Eye and face protection. 1917.91 Section 1917.91 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.91 Eye and face protection. (a)(1)(i) The employer shall ensure that each affected employee uses protective eye and face protection devices that comply...

29 CFR 1917.91 - Eye and face protection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Eye and face protection. 1917.91 Section 1917.91 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.91 Eye and face protection. (a)(1)(i) The employer shall ensure that each affected employee uses protective eye and face protection devices that comply...

Improved high-resolution ultrasonic imaging of the eye.

PubMed

Silverman, Ronald H; Ketterling, Jeffrey A; Mamou, Jonathan; Coleman, D Jackson

2008-01-01

Currently, virtually all clinical diagnostic ultrasound systems used in ophthalmology are based on fixed-focus, single-element transducers. High-frequency (> or = 20-MHz) transducers introduced to ophthalmology during the last decade have led to improved resolution and diagnostic capabilities for assessment of the anterior segment and the retina. However, single-element transducers are restricted to a small depth of field, limiting their capacity to image the eye as a whole. We fabricated a 20-MHz annular array probe prototype consisting of 5 concentric transducer elements and scanned an ex vivo human eye. Synthetically focused images of the bank eye showed improved depth of field and sensitivity, allowing simultaneous display of the anterior and posterior segments and the full lens contour. This capability may be useful in assessment of vitreoretinal pathologies and investigation of the accommodative mechanism.

Mobile Ultrasound Plane Wave Beamforming on iPhone or iPad using Metal- based GPU Processing

NASA Astrophysics Data System (ADS)

Hewener, Holger J.; Tretbar, Steffen H.

Mobile and cost effective ultrasound devices are being used in point of care scenarios or the drama room. To reduce the costs of such devices we already presented the possibilities of consumer devices like the Apple iPad for full signal processing of raw data for ultrasound image generation. Using technologies like plane wave imaging to generate a full image with only one excitation/reception event the acquisition times and power consumption of ultrasound imaging can be reduced for low power mobile devices based on consumer electronics realizing the transition from FPGA or ASIC based beamforming into more flexible software beamforming. The massive parallel beamforming processing can be done with the Apple framework "Metal" for advanced graphics and general purpose GPU processing for the iOS platform. We were able to integrate the beamforming reconstruction into our mobile ultrasound processing application with imaging rates up to 70 Hz on iPad Air 2 hardware.

Method and system to synchronize acoustic therapy with ultrasound imaging

NASA Technical Reports Server (NTRS)

Hossack, James (Inventor); Owen, Neil (Inventor); Bailey, Michael R. (Inventor)

2009-01-01

Interference in ultrasound imaging when used in connection with high intensity focused ultrasound (HIFU) is avoided by employing a synchronization signal to control the HIFU signal. Unless the timing of the HIFU transducer is controlled, its output will substantially overwhelm the signal produced by ultrasound imaging system and obscure the image it produces. The synchronization signal employed to control the HIFU transducer is obtained without requiring modification of the ultrasound imaging system. Signals corresponding to scattered ultrasound imaging waves are collected using either the HIFU transducer or a dedicated receiver. A synchronization processor manipulates the scattered ultrasound imaging signals to achieve the synchronization signal, which is then used to control the HIFU bursts so as to substantially reduce or eliminate HIFU interference in the ultrasound image. The synchronization processor can alternatively be implemented using a computing device or an application-specific circuit.

Transvaginal 3D Image-Guided High Intensity Focused Ultrasound Array

NASA Astrophysics Data System (ADS)

Held, Robert; Nguyen, Thuc Nghi; Vaezy, Shahram

2005-03-01

The goal of this project is to develop a transvaginal image-guided High Intensity Focused Ultrasound (HIFU) device using piezocomposite HIFU array technology, and commercially-available ultrasound imaging. Potential applications include treatment of uterine fibroids and abnormal uterine bleeding. The HIFU transducer was an annular phased array, with a focal length range of 30-60 mm, an elliptically-shaped aperture of 35×60 mm, and an operating frequency of 3 MHz. A pillow-shaped bag with water circulation will be used for coupling the HIFU energy into the tissue. An intra-cavity imaging probe (C9-5, Philips) was integrated with the HIFU array such that the focal axis of the HIFU transducer was within the image plane. The entire device will be covered by a gel-filled condom when inserted in the vaginal cavity. To control it, software packages were developed in the LabView programming environment. An imaging algorithm processed the ultrasound image to remove noise patterns due to the HIFU signal. The device will be equipped with a three-dimensional tracking system, using a six-degrees-of-freedom articulating arm. Necrotic lesions were produced in a tissue-mimicking phantom and a turkey breast sample for all focal lengths. Various HIFU doses allow various necrotic lesion shapes, including thin ellipsoidal, spherical, wide cylindrical, and teardrop-shaped. Software control of the device allows multiple foci to be activated sequentially for desired lesion patterns. Ultrasound imaging synchronization can be achieved using hardware signals obtained from the imaging system, or software signals determined empirically for various imaging probes. The image-guided HIFU device will provide a valuable tool in visualization of uterine fibroid tumors for the purposes of planning and subsequent HIFU treatment of the tumor, all in a 3D environment. The control system allows for various lesions of different shapes to be optimally positioned in the tumor to cover the entire tumor

Detecting eye movements in dynamic environments.

PubMed

Reimer, Bryan; Sodhi, Manbir

2006-11-01

To take advantage of the increasing number of in-vehicle devices, automobile drivers must divide their attention between primary (driving) and secondary (operating in-vehicle device) tasks. In dynamic environments such as driving, however, it is not easy to identify and quantify how a driver focuses on the various tasks he/she is simultaneously engaged in, including the distracting tasks. Measures derived from the driver's scan path have been used as correlates of driver attention. This article presents a methodology for analyzing eye positions, which are discrete samples of a subject's scan path, in order to categorize driver eye movements. Previous methods of analyzing eye positions recorded in a dynamic environment have relied completely on the manual identification of the focus of visual attention from a point of regard superimposed on a video of a recorded scene, failing to utilize information regarding movement structure in the raw recorded eye positions. Although effective, these methods are too time consuming to be easily used when the large data sets that would be required to identify subtle differences between drivers, under different road conditions, and with different levels of distraction are processed. The aim of the methods presented in this article are to extend the degree of automation in the processing of eye movement data by proposing a methodology for eye movement analysis that extends automated fixation identification to include smooth and saccadic movements. By identifying eye movements in the recorded eye positions, a method of reducing the analysis of scene video to a finite search space is presented. The implementation of a software tool for the eye movement analysis is described, including an example from an on-road test-driving sample.

Ultrasound liquid crystal lens

NASA Astrophysics Data System (ADS)

Shimizu, Yuki; Koyama, Daisuke; Fukui, Marina; Emoto, Akira; Nakamura, Kentaro; Matsukawa, Mami

2018-04-01

A variable-focus lens using a combination of liquid crystals and ultrasound is discussed. The lens uses a technique based on ultrasound vibration to control the molecular orientation of the liquid crystal. The lens structure is simple, with no mechanical moving parts and no transparent electrodes, which is helpful for device downsizing; the structure consists of a liquid crystal layer sandwiched between two glass substrates with a piezoelectric ring. The tens-of-kHz ultrasonic resonance flexural vibration used to excite the lens generates an acoustic radiation force on the liquid crystal layer to induce changes in the molecular orientation of the liquid crystal. The orientations of the liquid crystal molecules and the optical characteristics of the lens were investigated under ultrasound excitation. Clear optical images were observed through the lens, and the focal point could be controlled using the input voltage to the piezoelectric ring to give the lens its variable-focus action.

Awareness and Utilization of Welders' Personal Protective Eye Devices and Associated Factors: Findings and Lessons From a Nigerian Population.

PubMed

Eze, Boniface I; Okoye, Obiekwe; Aguwa, Emmanuel N

2015-04-01

This study assessed commercial welders' awareness and utilization of personal protective eye devices (PPEDs), and their associations, in Enugu, Nigeria, between January and March, 2011. The participants included 343 males, age 33.9 years±10.0 SD years. The participants reported high awareness of welding-associated ocular hazards (99.4%) and PPEDs (75.2%-98.3%), but low PPED possession and utilization rates. Cost and "presumed lack of utility" were the leading barriers to PPED possession; non-utilization was mainly attributed to "user inconvenience" and "presumed lack of protective benefit." PPED utilization was significantly associated with lower educational status (p=.030) and electric welding (p<.0001). The underlying causes are amenable to preventive occupational eye health education, enhanced ergonomics and affordability of PPEDs, and legislative enforcement of their use. © 2015 The Author(s).

Portable ultrasound in disaster triage: a focused review.

PubMed

Wydo, S M; Seamon, M J; Melanson, S W; Thomas, P; Bahner, D P; Stawicki, S P

2016-04-01

Ultrasound technology has become ubiquitous in modern medicine. Its applications span the assessment of life-threatening trauma or hemodynamic conditions, to elective procedures such as image-guided peripheral nerve blocks. Sonographers have utilized ultrasound techniques in the pre-hospital setting, emergency departments, operating rooms, intensive care units, outpatient clinics, as well as during mass casualty and disaster management. Currently available ultrasound devices are more affordable, portable, and feature user-friendly interfaces, making them well suited for use in the demanding situation of a mass casualty incident (MCI) or disaster triage. We have reviewed the existing literature regarding the application of sonology in MCI and disaster scenarios, focusing on the most promising and practical ultrasound-based paradigms applicable in these settings.

Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues

PubMed Central

Bok, Tae-Hoon; Kim, Juho; Bae, Jinho; Lee, Chong Hyun; Paeng, Dong-Guk

2014-01-01

The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM) system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270° ∼ 330° and at a distance range of 6 ∼ 7 mm, whereas the tissues of the other eye were observed in relative angle range of 160° ∼ 220° and at a distance range of 7.5 ∼ 9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system. PMID:25254305

On Biometrics With Eye Movements.

PubMed

Zhang, Youming; Juhola, Martti

2017-09-01

Eye movements are a relatively novel data source for biometric identification. When video cameras applied to eye tracking become smaller and more efficient, this data source could offer interesting opportunities for the development of eye movement biometrics. In this paper, we study primarily biometric identification as seen as a classification task of multiple classes, and secondarily biometric verification considered as binary classification. Our research is based on the saccadic eye movement signal measurements from 109 young subjects. In order to test the data measured, we use a procedure of biometric identification according to the one-versus-one (subject) principle. In a development from our previous research, which also involved biometric verification based on saccadic eye movements, we now apply another eye movement tracker device with a higher sampling frequency of 250 Hz. The results obtained are good, with correct identification rates at 80-90% at their best.

Feasibility of remote real-time guidance of a cardiac examination performed by novices using a pocket-sized ultrasound device.

PubMed

Mai, Tuan V; Ahn, David T; Phillips, Colin T; Agan, Donna L; Kimura, Bruce J

2013-01-01

Background. The potential of pocket-sized ultrasound devices (PUDs) to improve global healthcare delivery is limited by the lack of a suitable imaging protocol and trained users. Therefore, we investigated the feasibility of performing a brief, evidence-based cardiac limited ultrasound exam (CLUE) through wireless guidance of novice users. Methods. Three trainees applied PUDs on 27 subjects while directed by an off-site cardiologist to obtain a CLUE to screen for LV systolic dysfunction (LVSD), LA enlargement (LAE), ultrasound lung comets (ULC+), and elevated CVP (eCVP). Real-time remote audiovisual guidance and interpretation by the cardiologist were performed using the iPhone 4/iPod (FaceTime, Apple, Inc.) attached to the PUD and transmitted data wirelessly. Accuracy and technical quality of transmitted images were compared to on-site, gold-standard echo thresholds. Results. Novice versus sonographer imaging yielded technically adequate views in 122/135 (90%) versus 130/135 (96%) (P < 0.05). CLUE's combined SN, SP, and ACC were 0.67, 0.96, and 0.90. Technical adequacy (%) and accuracy for each abnormality (n) were LVSD (85%, 0.93, n = 5), LAE (89%, 0.74, n = 16), ULC+ (100%, 0.94, n = 5), and eCVP (78%, 0.91, n = 1). Conclusion. A novice can perform the CLUE using PUD when wirelessly guided by an expert. This method could facilitate PUD use for off-site bedside medical decision making and triaging of patients.

Ultrasound assisted dialysis of semi-permeable membrane devices for the simultaneous analysis of a wide number of persistent organic pollutants.

PubMed

Bustamante, Julen; Navarro, Patricia; Arana, Gorka; de Diego, Alberto; Madariaga, Juan Manuel

2013-09-30

A new procedure based on ultrasound assisted dialysis (UAD) for the simultaneous and quantitative extraction of a wide number of persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) or some other organochlorinated pesticides (OCPs) contained in semi-permeable membrane devices (SPMDs) has been developed. This extraction technique combines the advantages of the organic solvent dialysis (OSD) and the speed of the ultrasound assisted extraction. The extraction was performed in an ultrasound bath for 32 min placing the SPMD in a glass flask covered with 80 mL of hexane. This set-up is able to extract simultaneously up to 8 samples. The proposed method entails good repeatabilities (RSD 2-13%) and recoveries (around 100% for almost every analyte). Limits of detection were at ng SPMD(-1) level and enough for the determination of the target analytes in a slightly polluted aquatic environment, as it was tested by successfully comparing the OSD to the proposed methodology. Therefore, the results obtained show that the UAD can be a good alternative for the extraction of POPs in SPMDs as it requires short extraction times and solvent volumes, and provides a cleaner extract for the subsequent clean-up step. Moreover, it fits better than the OSD to the general requirements of Green Chemistry. Copyright © 2013 Elsevier B.V. All rights reserved.

Point-of-care cardiac ultrasound techniques in the physical examination: better at the bedside.

PubMed

Kimura, Bruce J

2017-07-01

The development of hand-carried, battery-powered ultrasound devices has created a new practice in ultrasound diagnostic imaging, called 'point-of-care' ultrasound (POCUS). Capitalising on device portability, POCUS is marked by brief and limited ultrasound imaging performed by the physician at the bedside to increase diagnostic accuracy and expediency. The natural evolution of POCUS techniques in general medicine, particularly with pocket-sized devices, may be in the development of a basic ultrasound examination similar to the use of the binaural stethoscope. This paper will specifically review how POCUS improves the limited sensitivity of the current practice of traditional cardiac physical examination by both cardiologists and non-cardiologists. Signs of left ventricular systolic dysfunction, left atrial enlargement, lung congestion and elevated central venous pressures are often missed by physical techniques but can be easily detected by POCUS and have prognostic and treatment implications. Creating a general set of repetitive imaging skills for these entities for application on all patients during routine examination will standardise and reduce heterogeneity in cardiac bedside ultrasound applications, simplify teaching curricula, enhance learning and recollection, and unify competency thresholds and practice. The addition of POCUS to standard physical examination techniques in cardiovascular medicine will result in an ultrasound-augmented cardiac physical examination that reaffirms the value of bedside diagnosis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effects of Device on Video Head Impulse Test (vHIT) Gain.

PubMed

Janky, Kristen L; Patterson, Jessie N; Shepard, Neil T; Thomas, Megan L A; Honaker, Julie A

2017-10-01

Numerous video head impulse test (vHIT) devices are available commercially; however, gain is not calculated uniformly. An evaluation of these devices/algorithms in healthy controls and patients with vestibular loss is necessary for comparing and synthesizing work that utilizes different devices and gain calculations. Using three commercially available vHIT devices/algorithms, the purpose of the present study was to compare: (1) horizontal canal vHIT gain among devices/algorithms in normal control subjects; (2) the effects of age on vHIT gain for each device/algorithm in normal control subjects; and (3) the clinical performance of horizontal canal vHIT gain between devices/algorithms for differentiating normal versus abnormal vestibular function. Prospective. Sixty-one normal control adult subjects (range 20-78) and eleven adults with unilateral or bilateral vestibular loss (range 32-79). vHIT was administered using three different devices/algorithms, randomized in order, for each subject on the same day: (1) Impulse (Otometrics, Schaumberg, IL; monocular eye recording, right eye only; using area under the curve gain), (2) EyeSeeCam (Interacoustics, Denmark; monocular eye recording, left eye only; using instantaneous gain), and (3) VisualEyes (MicroMedical, Chatham, IL, binocular eye recording; using position gain). There was a significant mean difference in vHIT gain among devices/algorithms for both the normal control and vestibular loss groups. vHIT gain was significantly larger in the ipsilateral direction of the eye used to measure gain; however, in spite of the significant mean differences in vHIT gain among devices/algorithms and the significant directional bias, classification of "normal" versus "abnormal" gain is consistent across all compared devices/algorithms, with the exception of instantaneous gain at 40 msec. There was not an effect of age on vHIT gain up to 78 years regardless of the device/algorithm. These findings support that vHIT gain is

Macular hole: 10 and 20-MHz ultrasound and spectral-domain optical coherence tomography.

PubMed

Bottós, Juliana Mantovani; Torres, Virginia Laura Lucas; Kanecadan, Liliane Andrade Almeida; Martinez, Andrea Alejandra Gonzalez; Moraes, Nilva Simeren Bueno; Maia, Mauricio; Allemann, Norma

2012-01-01

Optical coherence tomography (OCT) is valuable for macula evaluation. However, as this technique relies on light energy it cannot be performed in the presence of opaque media. In such cases, the ultrasound (US) may predict some macular features. The aim of this study was to characterize images obtained by ultrasound with 10 and 20-MHz transducers comparing to OCT, as well as to analyze the relationship between the vitreous and retina in eyes with macular hole (MH). 29 eyes of 22 patients with biomicroscopic evidence of MH at different stages were included. All patients were evaluated using ultrasonography with 10 and 20-MHz transducers and OCT. OCT identified signs of MH in 25 of 29 eyes. The remaining 4 cases not identified by US were pseudoholes caused by epiretinal membranes. In MH stages I (2 eyes) and II (1 eye), both transducers were not useful to analyze the macular thickening, but suggestive findings as macular irregularity, operculum or partial posterior vitreous detachment (PVD) were highlighted. In stages III (14 eyes) and IV (5 eyes), both transducers identified the double hump irregularity and thickening. US could measure the macular thickness and other suggestive findings for MH: operculum, vitreomacular traction and partial or complete PVD. In cases of pseudoholes, US identified irregularities macular contour and a discrete depression. 10-MHz US was useful for an overall assessment of the vitreous body as well as its relationship to the retina. The 20-MHz transducer allowed valuable information on the vitreomacular interface and macular contour. OCT provides superior quality for fine morphological study of macular area, except in cases of opaque media. In these cases, and even if OCT is not available, the combined US study is able to provide a valid evaluation of the macular area improving therapeutic approach.

Mediastinal Adenopathy in India: Through the Eyes of Endobranchial Ultrasound.

PubMed

Dhamija, Amit; Basu, Arup; Sharma, Vishal; Bakshi, Pooja; Verma, Kusum

2015-09-01

Aetiology of mediastinal adenopathy is likely to vary with geographic location and socioeconomic status of a population. Whilst most of adenopathy in the West could be attributed to malignant disorders, causes of the same in a developing country like India has not been extensively studied earlier due to lack of less invasive tools to sample these nodes for cytological and microbiological analysis. Endobronchial ultrasound (EBUS) helps us reach these nodes as a minimally invasive procedure to take aspirations under real-time ultrasound guidance. The aim of the present study is to study the aetiology of mediastinal adenopathy in our population with the help of EBUS. This was a retrospective analysis of all EBUS procedures done by the authors and the diagnosis thus obtained at Sir Ganga Ram Hospital, New Delhi, India between April 2010 and December 2011. A total of 300 patients underwent EBUS in the above period. Most common aetiology encountered in our population was a granulomatous disorder (53% cases) like tuberculosis and sarcoidosis whilst malignancy was third in order of diagnosis (17% cases). Lymph node enlargement due to anthracosis was another uncommon aetiology encountered in the study (5% cases). Benign granulomatous disorders like tuberculosis and sarcoidosis are the most common causes of mediastinal adenopathy in our population. EBUS is proving its worth for diagnosing mediastinal adenopathy. © Journal of the Association of Physicians of India 2011.

Counterbalancing the use of ultrasound contrast agents by a cavitation-regulated system.

PubMed

Desjouy, C; Fouqueray, M; Lo, C W; Muleki Seya, P; Lee, J L; Bera, J C; Chen, W S; Inserra, C

2015-09-01

The stochastic behavior of cavitation can lead to major problems of initiation and maintenance of cavitation during sonication, responsible of poor reproducibility of US-induced bioeffects in the context of sonoporation for instance. To overcome these disadvantages, the injection of ultrasound contrast agents as cavitation nuclei ensures fast initiation and lower acoustic intensities required for cavitation activity. More recently, regulated-cavitation devices based on the real-time modulation of the applied acoustic intensity have shown their potential to maintain a stable cavitation state during an ultrasonic shot, in continuous or pulsed wave conditions. In this paper is investigated the interest, in terms of cavitation activity, of using such regulated-cavitation device or injecting ultrasound contrast agents in the sonicated medium. When using fixed applied acoustic intensity, results showed that introducing ultrasound contrast agents increases reproducibility of cavitation activity (coefficient of variation 62% and 22% without and with UCA, respectively). Moreover, the use of the regulated-cavitation device ensures a given cavitation activity (coefficient of variation less 0.4% in presence of UCAs or not). This highlights the interest of controlling cavitation over time to free cavitation-based application from the use of UCAs. Interestingly, during a one minute sonication, while ultrasound contrast agents progressively disappear, the regulated-cavitation device counterbalance their destruction to sustain a stable inertial cavitation activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of Ultrasound Energy as a New Drug Delivery System

NASA Astrophysics Data System (ADS)

Tachibana, Katsuro; Tachibana, Shunro

1999-05-01

Ultrasound has been in use for the last three decades as amodality for diagnostic imaging in medicine. Recently, there have beennumerous reports on the application of nonthermal ultrasound energyfor targeting or controlling drug release. This new concept oftherapeutic ultrasound combined with drugs has led to much excitementin various medical fields. Ultrasound energy can enhance the effectsof thrombolytic agents such as urokinase. Therapeutic ultrasoundcatheters are currently being developed for treatment ofcardiovascular diseases. Devices with ultrasound transducers implantedin transdermal drug patches are also being evaluated for possibledelivery of insulin through the skin. Chemical activation of drugs byultrasound energy for treatment of cancers is another new fieldrecently termed “Sonodynamic Therapy”. Various examples of ultrasoundapplication are under investigation which could lead to revolutionarydrug delivery systems in the future.

Acoustic bubble sorting for ultrasound contrast agent enrichment.

PubMed

Segers, Tim; Versluis, Michel

2014-05-21

An ultrasound contrast agent (UCA) suspension contains encapsulated microbubbles with a wide size distribution, with radii ranging from 1 to 10 μm. Medical transducers typically operate at a single frequency, therefore only a small selection of bubbles will resonate to the driving ultrasound pulse. Thus, the sensitivity can be improved by narrowing down the size distribution. Here, we present a simple lab-on-a-chip method to sort the population of microbubbles on-chip using a traveling ultrasound wave. First, we explore the physical parameter space of acoustic bubble sorting using well-defined bubble sizes formed in a flow-focusing device, then we demonstrate successful acoustic sorting of a commercial UCA. This novel sorting strategy may lead to an overall improvement of the sensitivity of contrast ultrasound by more than 10 dB.

[Occupational risk caused by ultrasound in medicine].

PubMed

Magnavita, N; Fileni, A

1994-01-01

Ultrasound (US) is extensively used in the medical field for its therapeutic and diagnostic applications. US units are commonly found in hospitals and clinics of all sizes, and a growing number of medical staff such as doctors and nurses are exposed to hand-transmitted ultrasound waves in their work-place. This review discusses the available information on the occupational risk of the operators using diagnostic and therapeutic ultrasound devices. The new occupational groups of medical workers who use ultrasound (diagnostic, surgical, sterilization, and physiotherapeutic) equipment are exposed to contact ultrasound waves. Contact ultrasound -- i.e., no airspace between the energy source and the biological tissue -- is much more hazardous than exposure to airborne ultrasound because air transmits less than one percent of this kind of energy. In spite of being a non-ionizing radiation with an excellent safety record, US is likely to induce some changes in the exposed organ. Recent Russian studies indicate that the hospital workers who have been long exposed to ultrasound at work may develop neurovascular dose-dependent disorders of the peripheral nervous system in the form of the angiodystonic syndrome of vegetative polyneuritis of the hands. In some Scandinavian studies, female physiotherapists (exposed to ultrasound and short waves) exhibit increased rate of spontaneous abortions and congenital malformations, but no definite conclusion can be drawn on the basis of these results alone. Trends in exposure for diagnostic ultrasound equipment over the last two decades show a continuous increase. While there is no reason for alarm, there is a growing need for avoiding unnecessary exposure to medical workers.

Co-registered photoacoustic, thermoacoustic, and ultrasound mouse imaging

NASA Astrophysics Data System (ADS)

Reinecke, Daniel R.; Kruger, Robert A.; Lam, Richard B.; DelRio, Stephen P.

2010-02-01

We have constructed and tested a prototype test bed that allows us to form 3D photoacoustic CT images using near-infrared (NIR) irradiation (700 - 900 nm), 3D thermoacoustic CT images using microwave irradiation (434 MHz), and 3D ultrasound images from a commercial ultrasound scanner. The device utilizes a vertically oriented, curved array to capture the photoacoustic and thermoacoustic data. In addition, an 8-MHz linear array fixed in a horizontal position provides the ultrasound data. The photoacoustic and thermoacoustic data sets are co-registered exactly because they use the same detector. The ultrasound data set requires only simple corrections to co-register its images. The photoacoustic, thermoacoustic, and ultrasound images of mouse anatomy reveal complementary anatomic information as they exploit different contrast mechanisms. The thermoacoustic images differentiate between muscle, fat and bone. The photoacoustic images reveal the hemoglobin distribution, which is localized predominantly in the vascular space. The ultrasound images provide detailed information about the bony structures. Superposition of all three images onto a co-registered hybrid image shows the potential of a trimodal photoacoustic-thermoacoustic-ultrasound small-animal imaging system.

A resonance-free nano-film airborne ultrasound emitter

NASA Astrophysics Data System (ADS)

Daschewski, Maxim; Harrer, Andrea; Prager, Jens; Kreutzbruck, Marc; Beck, Uwe; Lange, Thorid; Weise, Matthias

2013-01-01

In this contribution we present a novel thermo-acoustic approach for the generation of broad band airborne ultrasound and investigate the applicability of resonance-free thermo-acoustic emitters for very short high pressure airborne ultrasound pulses. We report on measurements of thermo-acoustic emitter consisting of a 30 nm thin metallic film on a usual soda-lime glass substrate, generating sound pressure values of more than 140 dB at 60 mm distance from the transducer and compare the results with conventional piezoelectric airborne ultrasound transducers. Our experimental investigations show that such thermo-acoustic devices can be used as broad band emitters using pulse excitation.

An ultrasound wearable system for the monitoring and acceleration of fracture healing in long bones.

PubMed

Protopappas, Vasilios C; Baga, Dina A; Fotiadis, Dimitrios I; Likas, Aristidis C; Papachristos, Athanasios A; Malizos, Konstantinos N

2005-09-01

An ultrasound wearable system for remote monitoring and acceleration of the healing process in fractured long bones is presented. The so-called USBone system consists of a pair of ultrasound transducers, implanted into the fracture region, a wearable device and a centralized unit. The wearable device is responsible to carry out ultrasound measurements using the axial-transmission technique and initiate therapy sessions of low-intensity pulsed ultrasound. The acquired measurements and other data are wirelessly transferred from the patient-site to the centralized unit, which is located in a clinical setting. The evaluation of the system on an animal tibial osteotomy model is also presented. A dataset was constructed for monitoring purposes consisting of serial ultrasound measurements, follow-up radiographs, quantitative computed tomography-based densitometry and biomechanical data. The animal study demonstrated the ability of the system to collect ultrasound measurements in an effective and reliable fashion and participating orthopaedic surgeons accepted the system for future clinical application. Analysis of the acquired measurements showed that the pattern of evolution of the ultrasound velocity through healing bones over the postoperative period monitors a dynamic healing process. Furthermore, the ultrasound velocity of radiographically healed bones returns to 80% of the intact bone value, whereas the correlation coefficient of the velocity with the material and mechanical properties of the healing bone ranges from 0.699 to 0.814. The USBone system constitutes the first telemedicine system for the out-hospital management of patients sustained open fractures and treated with external fixation devices.

Measurement of corneal tangent modulus using ultrasound indentation.

PubMed

Wang, Li-Ke; Huang, Yan-Ping; Tian, Lei; Kee, Chea-Su; Zheng, Yong-Ping

2016-09-01

Biomechanical properties are potential information for the diagnosis of corneal pathologies. An ultrasound indentation probe consisting of a load cell and a miniature ultrasound transducer as indenter was developed to detect the force-indentation relationship of the cornea. The key idea was to utilize the ultrasound transducer to compress the cornea and to ultrasonically measure the corneal deformation with the eyeball overall displacement compensated. Twelve corneal silicone phantoms were fabricated with different stiffness for the validation of measurement with reference to an extension test. In addition, fifteen fresh porcine eyes were measured by the developed system in vitro. The tangent moduli of the corneal phantoms calculated using the ultrasound indentation data agreed well with the results from the tensile test of the corresponding phantom strips (R(2)=0.96). The mean tangent moduli of the porcine corneas measured by the proposed method were 0.089±0.026MPa at intraocular pressure (IOP) of 15mmHg and 0.220±0.053MPa at IOP of 30mmHg, respectively. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) of tangent modulus were 14.4% and 0.765 at 15mmHg, and 8.6% and 0.870 at 30mmHg, respectively. The preliminary study showed that ultrasound indentation could be applied to the measurement of corneal tangent modulus with good repeatability and improved measurement accuracy compared to conventional surface displacement-based measurement method. The ultrasound indentation can be a potential tool for the corneal biomechanical properties measurement in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

Eye and Face Protection in School Science

ERIC Educational Resources Information Center

Kaufman, Jim

2006-01-01

Choosing what eye and face protection to provide for the high school science laboratory is often a challenge. Science teachers and school administrators may not fully understand the relevant safety regulations and standards or be able to correctly identify the various types of eye protection devices. Although some schools have received training…

A cMUT probe for ultrasound-guided focused ultrasound targeted therapy.

PubMed

Gross, Dominique; Coutier, Caroline; Legros, Mathieu; Bouakaz, Ayache; Certon, Dominique

2015-06-01

Ultrasound-mediated targeted therapy represents a promising strategy in the arsenal of modern therapy. Capacitive micromachined ultrasonic transducer (cMUT) technology could overcome some difficulties encountered by traditional piezoelectric transducers. In this study, we report on the design, fabrication, and characterization of an ultrasound-guided focused ultrasound (USgFUS) cMUT probe dedicated to preclinical evaluation of targeted therapy (hyperthermia, thermosensitive liposomes activation, and sonoporation) at low frequency (1 MHz) with simultaneous ultrasonic imaging and guidance (15 to 20 MHz). The probe embeds two types of cMUT arrays to perform the modalities of targeted therapy and imaging respectively. The wafer-bonding process flow employed for the manufacturing of the cMUTs is reported. One of its main features is the possibility of implementing two different gap heights on the same wafer. All the design and characterization steps of the devices are described and discussed, starting from the array design up to the first in vitro measurements: optical (microscopy) and electrical (impedance) measurements, arrays' electroacoustic responses, focused pressure field mapping (maximum peak-to-peak pressure = 2.5 MPa), and the first B-scan image of a wire-target phantom.

Micromolded thick PZT sol gel composite structures for ultrasound transducer devices operating at high frequencies

NASA Astrophysics Data System (ADS)

Pang, Guofeng

The objective of this work has been to design and develop a micromolding technique useful for batch fabrication to microfabricate 3D ceramic structures for device purposes using a sol gel composite processing technique and deep photolithography (UV LIGA). These structures may be the elements of ultrasound transducers, the structures associated with electronic packaging, or microstructures for microfluidic applications. To demonstrate the technique, the project has focused on the design and fabrication of annular and linear arrays for high frequency (>20 MHz) ultrasound imaging applications, particularly where an electronically steered imaging modality is employed. Other typical micromolded structures have been demonstrated to show the potential for micromolding. The transferability of the technique for industrial purposes is proposed. Using a sol gel composite process, the critical components in this technique are mold making, mold filling, material-processing, demolding, top electrode and essential material characterization. Two types of molds have been created using UV LIGA and/or electroplating. A purely organic mold made of Su-8 epoxy based photo-resist has shown tremendous performance for micromolding. The transducer packaging process has also been designed and evaluated at the laboratory level. A Su-8 micro bridge and bond pad has been used for wire bonding purposes. A 5-element annular array transducer has been fabricated by this technique and fully packaged. The micromolded piezoceramic structures have been characterized. The pulse echo performance of each element and the focusing performance of 5 elements of a packaged transducer array have been evaluated using a coaxial cable and a cable delay system.

High-Intensity Focused Ultrasound (HIFU) Using Sonablate® Devices for the Treatment of Benign Prostatic Hyperplasia and Localized Prostate Cancer: 18-year experience

NASA Astrophysics Data System (ADS)

Uchida, Toyoaki

2011-09-01

From 1993 to 2010, we have treated 156 patients benign prostatic hyperplasia (BPH) and 1,052 patients localized prostate cancer high-intensity focused ultrasound (HIFU). Four different HIFU devices, SonablateR-200, SonablateR-500, SonablateR-500 version 4 and Sonablate® TCM, have been used for this study. Clinical outcome of HIFU for BPH did not show any superior effects to transurethral resection of the prostate, laser surgery or transurethral vapolization of the prostate. However, HIFU appears to be a safe and minimally invasive therapy for patients with localized prostate cancer, especially low- and intermediate-risk patients. The rate of clinical outcome has significantly improved over the years due to technical improvements in the device.

Morphometric assessment of normal human ciliary body using ultrasound biomicroscopy.

PubMed

Okamoto, Yoshifumi; Okamoto, Fumiki; Nakano, Shinichiro; Oshika, Tetsuro

2017-12-01

To quantitatively assess the biometry of the ciliary body in normal human eyes using ultrasound biomicroscopy. We evaluated 85 eyes of 85 normal subjects (35 men and 50 women), whose age ranged from 11 to 86 years (mean ± SD, 56.8 ± 20.4 years). The eyes were assessed along the 3-, 6-, 9-, and 12-o'clock meridians relative to the center of the cornea. Clinical data were collected, including age, axial length, ciliary body length (CBL), ciliary body thickness (CBT), anterior chamber depth, iris root thickness, trabecular-iris angle, and scleral-ciliary process angle. Axial length was measured using A-scan ultrasonography. CBL and CBT tended to be larger in the superior than in the inferior quadrant, but the differences among the four quadrants were not statistically significant. The average CBL showed a significant positive correlation with the average CBT (r = 0.40, P < 0.001). Average CBL and CBT were significantly correlated with axial length (r = 0.33, P = 0.031; r = 0.46, P < 0.01 respectively). In addition, the average CBL was significantly correlated with anterior chamber depth (r = 0.23, P < 0.05), trabecular-iris angle (r = 0.29, P = 0.01), and scleral-ciliary process angle (r = 0.40, P < 0.001). Ultrasound biomicroscopic imaging demonstrated that the ciliary body is similar in size in all circumferences, and eyes with longer axial length have an elongated and thicker ciliary body. The values obtained in the present study may serve as standard clinical references.

The potential of ultrasound in cardiac pacing and rhythm modulation.

PubMed

Kohut, Andrew R; Vecchio, Christopher; Adam, Dan; Lewin, Peter A

2016-09-01

This review examines the potential for ultrasound to induce or otherwise influence cardiac pacing and rhythm modulation. Of particular interest is the possibility of developing new, truly non-invasive, nonpharmacological, acute and chronic, ultrasound-based arrhythmia treatments. Such approaches would not depend upon implanted or indwelling devices of any kind and would use ultrasound at diagnostic exposure levels (so as not to harm the heart or surrounding tissues). It is known that ultrasound can cause cardiomyocyte depolarization and a variety of underlying mechanisms have been proposed. Expert commentary: Questions still remain regarding the effect of exposure parameters and work will also be necessary to identify the optimal target regions within the heart if ultrasound energy is to be used to induce safe and reliable pacing in a clinical setting.

Preliminary study of ergonomic behavior during simulated ultrasound-guided regional anesthesia using a head-mounted display.

PubMed

Udani, Ankeet D; Harrison, T Kyle; Howard, Steven K; Kim, T Edward; Brock-Utne, John G; Gaba, David M; Mariano, Edward R

2012-08-01

A head-mounted display provides continuous real-time imaging within the practitioner's visual field. We evaluated the feasibility of using head-mounted display technology to improve ergonomics in ultrasound-guided regional anesthesia in a simulated environment. Two anesthesiologists performed an equal number of ultrasound-guided popliteal-sciatic nerve blocks using the head-mounted display on a porcine hindquarter, and an independent observer assessed each practitioner's ergonomics (eg, head turning, arching, eye movements, and needle manipulation) and the overall block quality based on the injectate spread around the target nerve for each procedure. Both practitioners performed their procedures without directly viewing the ultrasound monitor, and neither practitioner showed poor ergonomic behavior. Head-mounted display technology may offer potential advantages during ultrasound-guided regional anesthesia.

Simplified stereo-optical ultrasound plane calibration

NASA Astrophysics Data System (ADS)

Hoßbach, Martin; Noll, Matthias; Wesarg, Stefan

2013-03-01

Image guided therapy is a natural concept and commonly used in medicine. In anesthesia, a common task is the injection of an anesthetic close to a nerve under freehand ultrasound guidance. Several guidance systems exist using electromagnetic tracking of the ultrasound probe as well as the needle, providing the physician with a precise projection of the needle into the ultrasound image. This, however, requires additional expensive devices. We suggest using optical tracking with miniature cameras attached to a 2D ultrasound probe to achieve a higher acceptance among physicians. The purpose of this paper is to present an intuitive method to calibrate freehand ultrasound needle guidance systems employing a rigid stereo camera system. State of the art methods are based on a complex series of error prone coordinate system transformations which makes them susceptible to error accumulation. By reducing the amount of calibration steps to a single calibration procedure we provide a calibration method that is equivalent, yet not prone to error accumulation. It requires a linear calibration object and is validated on three datasets utilizing di erent calibration objects: a 6mm metal bar and a 1:25mm biopsy needle were used for experiments. Compared to existing calibration methods for freehand ultrasound needle guidance systems, we are able to achieve higher accuracy results while additionally reducing the overall calibration complexity. Ke

Ultrasonographic diagnosis of early pregnancy in cattle using different ultrasound systems.

PubMed

Racewicz, Przemysław; Sickinger, Marlene; Włodarek, Jan; Jaśkowski, Jędrzej M

2016-06-16

To evaluate the efficiency of different ultrasound devices in achieving an early diagnosis of pregnancy in dairy herds. A total of 1976 Holstein Friesian cows and heifers were artificially inseminated (AI) according to the herd manager's regime. Pregnancy diagnostics were performed between day 26 and 35 after AI using six different types of ultrasound systems (linear vs. sector scanners). Manual rectal palpation between day 45 and 60 after AI was used as the gold standard for pregnancy diagnostics. Sensitivity (SENS), specificity (SPEC), positive (PPV) and negative predictive value (NPV) and diagnostic accuracy (ACC) of the diagnostic measures were determined. Average SENS was 82% (range 67.7-95.2%) with a mean SPEC of 73% (range 50.0-81.0%). ACC was 78.2% with a minimum of 64.6% and a maximum of 89.4%, depending on the ultrasound system. The PPV (ratio of the number of pregnant cows with a positive examination result to the number of cows actually pregnant) was 80.8% (range 59.1-88.1%), whereas the NPV (defined as the ratio of the number of cows correctly diagnosed negative to the number of cows actually open) was 74.4% (72.3-91.9%). Significant differences for these parameters were found depending on the ultrasound system used (p ≤ 0.01; Cramer's V. = 0.14). Regardless of the ultrasound device used, early pregnancy diagnostics between day 26 and 35 show a moderate diagnostic efficiency. Comparing the accuracy of the different devices, there may be a significant influence of type and technical parameters. Even though ultrasound systems with mechanical sector probes are not as convenient to use as systems with linear probes, according to this study, sector scanners are a reasonable alternative.

[Feasibility of device closure for multiple atrial septal defects using 3D printing and ultrasound-guided intervention technique].

PubMed

Qiu, X; Lü, B; Xu, N; Yan, C W; Ouyang, W B; Liu, Y; Zhang, F W; Yue, Z Q; Pang, K J; Pan, X B

2017-04-25

Objective: To investigate the feasibility of trans-catheter closure of multiple atrial septal defects (ASD) monitored by trans-thoracic echocardiography (TTE) under the guidance of 3D printing heart model. Methods: Between April and August 2016, a total of 21 patients (8 male and 13 female) with multiple ASD in Fuwai Hospital of Chinese Academy of Medical Sciences underwent CT scan and 3-dimensional echocardiography for heart disease model produced by 3D printing technique. The best occlusion program was determined through the simulation test on the model. Percutaneous device closure of multiple ASD was performed follow the predetermined program guided by TTE. Clinical follow-up including electrocardiogram and TTE was arranged at 1 month after the procedure. Results: The trans-catheter procedure was successful in all 21 patients using a single atrial septal occluder. Mild residual shunt was found in 5 patient in the immediate postoperative period, 3 of them were disappeared during postoperative follow-up. There was no death, vascular damage, arrhythmia, device migration, thromboembolism, valvular dysfunction during the follow-up period. Conclusion: The use of 3D printing heart model provides a useful reference for transcatheter device closure of multiple ASD achieving through ultrasound-guided intervention technique, which appears to be safe and feasible with good outcomes of short-term follow-up.

B-mode ultrasonography biometry of the Amazon Parrot (Amazona aestiva) eye.

PubMed

Lehmkuhl, Ricardo C; Almeida, Mariana F; Mamprim, Maria J; Vulcano, Luiz C

2010-09-01

Ultrasonographic evaluation of the eye is a relatively recent addition to routine ophthalmic diagnostics in small animal ophthalmology. Some parameters for ophthalmic biometry have been established. There are few studies in clinical avian ophthalmology that describe ultrasound images of eye in some nocturnal avian species and in other birds that do not belong to the Brazilian fauna, but the psittacine family is not represented. The purpose of this study was to describe the following measurements: the distances between cornea and anterior lens capsule (D1) between the anterior and posterior lens capsule (D2), between posterior lens capsule and optic papilla (D3) and the axial length. Sixty four transpalpebral ocular ultrasound examinations were performed on 32 Blue fronted Amazon parrots (Amazona aestiva) with no history of previous ophthalmic disease. The measurements were taken in sagital planes using a 10 MHz linear probe without a standoff pad. The mean values for the left eye were; D1 0.17 ± 0.03 cm, D2 0.35 ± 0.02 cm, D3 0.73 ± 0.04 cm and the axial length 1.26 ± 0.06 cm. In the right eye D1 0.17 ± 0.02 cm, D2 0.34 ± 0.02 cm, D3 0.74 ± 0.03 cm and the axial length 1.25 ± 0.05 cm. No significant statistical difference was observed among the birds or between the left and right eye. The description of these parameters will allow the veterinary practitioner to evaluate the structural changes that specific diseases may cause in these animals.

An ergonomic handheld ultrasound probe providing contact forces and pose information.

PubMed

Yohan Noh; Housden, R James; Gomez, Alberto; Knight, Caroline; Garcia, Francesca; Hongbin Liu; Razavi, Reza; Rhode, Kawal; Althoefer, Kaspar

2015-08-01

This paper presents a handheld ultrasound probe which is integrated with sensors to measure force and pose (position/orientation) information. Using an integrated probe like this, one can relate ultrasound images to spatial location and create 3D ultrasound maps. The handheld device can be used by sonographers and also easily be integrated with robot arms for automated sonography. The handheld device is ergonomically designed; rapid attachment and removal of the ultrasound transducer itself is possible using easy-to-operate clip mechanisms. A cable locking mechanism reduces the impact that gravitational and other external forces have (originating from data and power supply cables connected to the probe) on our measurements. Gravitational errors introduced by the housing of the probe are compensated for using knowledge of the housing geometry and the integrated pose sensor that provides us with accurate orientation information. In this paper, we describe the handheld probe with its integrated force/pose sensors and our approach to gravity compensation. We carried out a set of experiments to verify the feasibility of our approach to obtain accurate spatial information of the handheld probe.

Comparison of central corneal thickness measurements with a rotating scheimpflug camera, a specular microscope, optical low-coherence reflectometry, and ultrasound pachymetry in keratoconic eyes.

PubMed

Cinar, Yasin; Cingu, Abdullah Kursat; Turkcu, Fatih Mehmet; Cinar, Tuba; Sahin, Alparslan; Yuksel, Harun; Ari, Seyhmus

2015-03-01

To compare central corneal thickness (CCT) measurements with a rotating Scheimpflug camera (RSC), noncontact specular microscopy (SM), optical low-coherence reflectometry (OLCR), and ultrasonic pachymetry (UP) in keratoconus (KC) patients. In this prospective study, four CCT measurements taken with an RSC, SM, OLCR, and UP were compared in 81 eyes of 44 consecutive KC patients. The KC patients were divided into four subgroups according to Amsler-Krumeich's KC classification. The RSC and UP measurements of the CCT were not statistically significant in all the groups. Comparison of the SM vs. the OLCR measurements yielded statistically significant differences in all the KC patients and in all KC stages. In all the KC patients, RSC and OLCR showed a high correlation coefficient factor (r = 0.87, p = 0.000). CCT measurements with RSC are comparable to those achieved with UP. Compared with the other devices, according to SM measurements, the central cornea is thicker in all keratoconic eyes and in all KC grades, and it is thinner according to OLCR. RSC, UP, SM, and OLCR should not be used interchangeably in keratoconic eyes.

Assistive technology for ultrasound-guided central venous catheter placement.

PubMed

Ikhsan, Mohammad; Tan, Kok Kiong; Putra, Andi Sudjana

2018-01-01

This study evaluated the existing technology used to improve the safety and ease of ultrasound-guided central venous catheterization. Electronic database searches were conducted in Scopus, IEEE, Google Patents, and relevant conference databases (SPIE, MICCAI, and IEEE conferences) for related articles on assistive technology for ultrasound-guided central venous catheterization. A total of 89 articles were examined and pointed to several fields that are currently the focus of improvements to ultrasound-guided procedures. These include improving needle visualization, needle guides and localization technology, image processing algorithms to enhance and segment important features within the ultrasound image, robotic assistance using probe-mounted manipulators, and improving procedure ergonomics through in situ projections of important information. Probe-mounted robotic manipulators provide a promising avenue for assistive technology developed for freehand ultrasound-guided percutaneous procedures. However, there is currently a lack of clinical trials to validate the effectiveness of these devices.

Comparison of Optical versus Ultrasonic Biometry in Keratoconic Eyes

PubMed Central

Çınar, Yasin; Cingü, Abdullah Kürşat; Şahin, Muhammed; Yüksel, Harun; Türkcü, Fatih Mehmet; Çınar, Tuba; Çaça, İhsan

2013-01-01

Purpose. To compare the measurements of optical versus ultrasonic biometry devices in keratoconic eyes. Materials and Methods. Forty-two eyes of 42 keratoconus (KC) patients enrolled in the study were examined. Clinical and demographic characteristics of the patients were noted, and detailed ophthalmological examination was performed. Following Pentacam measurements, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were obtained using the Lenstar and US biometer to determine the reproducibility of the measurements between the two devices in keratoconic eyes. The Bland-Altman method was used to describe the agreement between the two devices. Results. The Lenstar could not measure at least one of the biometric properties in one eye and did not automatically give the corrected ACD in 2/3 of our study population. The Lenstar measured CCT (average difference 5.4 ± 19.6 µm; ICC = 0.90; P < 0.001), LT (average difference 0.13 ± 0.17 mm; ICC = 0.67; P < 0.001), and AL (average difference 0.10 ± 0.76 mm; ICC = 0.75; P < 0.001) thinner than US biometer, whereas it measured ACD (average difference 0.18 ± 0.17 mm; ICC = 0.85; P < 0.001) deeper than US biometer in keratoconic eyes. Conclusion. Although the difference between the measurements obtained using the two devices might be clinically acceptable, US biometry and Lenstar should not be used interchangeably for biometric measurements in KC patients. PMID:23986865

Comparison of Optical versus Ultrasonic Biometry in Keratoconic Eyes.

PubMed

Cınar, Yasin; Cingü, Abdullah Kürşat; Sahin, Muhammed; Sahin, Alparslan; Yüksel, Harun; Türkcü, Fatih Mehmet; Cınar, Tuba; Caça, Ihsan

2013-01-01

Purpose. To compare the measurements of optical versus ultrasonic biometry devices in keratoconic eyes. Materials and Methods. Forty-two eyes of 42 keratoconus (KC) patients enrolled in the study were examined. Clinical and demographic characteristics of the patients were noted, and detailed ophthalmological examination was performed. Following Pentacam measurements, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were obtained using the Lenstar and US biometer to determine the reproducibility of the measurements between the two devices in keratoconic eyes. The Bland-Altman method was used to describe the agreement between the two devices. Results. The Lenstar could not measure at least one of the biometric properties in one eye and did not automatically give the corrected ACD in 2/3 of our study population. The Lenstar measured CCT (average difference 5.4 ± 19.6 µm; ICC = 0.90; P < 0.001), LT (average difference 0.13 ± 0.17 mm; ICC = 0.67; P < 0.001), and AL (average difference 0.10 ± 0.76 mm; ICC = 0.75; P < 0.001) thinner than US biometer, whereas it measured ACD (average difference 0.18 ± 0.17 mm; ICC = 0.85; P < 0.001) deeper than US biometer in keratoconic eyes. Conclusion. Although the difference between the measurements obtained using the two devices might be clinically acceptable, US biometry and Lenstar should not be used interchangeably for biometric measurements in KC patients.

Sonoporation of adherent cells under regulated ultrasound cavitation conditions.

PubMed

Muleki Seya, Pauline; Fouqueray, Manuela; Ngo, Jacqueline; Poizat, Adrien; Inserra, Claude; Béra, Jean-Christophe

2015-04-01

A sonoporation device dedicated to the adherent cell monolayer has been implemented with a regulation process allowing the real-time monitoring and control of inertial cavitation activity. Use of the cavitation-regulated device revealed first that adherent cell sonoporation efficiency is related to inertial cavitation activity, without inducing additional cell mortality. Reproducibility is enhanced for the highest sonoporation rates (up to 17%); sonoporation efficiency can reach 26% when advantage is taken of the standing wave acoustic configuration by applying a frequency sweep with ultrasound frequency tuned to the modal acoustic modes of the cavity. This device allows sonoporation of adherent and suspended cells, and the use of regulation allows some environmental parameters such as the temperature of the medium to be overcome, resulting in the possibility of cell sonoporation even at ambient temperature. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Rapid Diagnosis of an Ulnar Fracture with Portable Hand-Held Ultrasound

NASA Technical Reports Server (NTRS)

Kirkpatrick, Andrew W.; Brown, Ross; Diebel, Lawrence N.; Nicolaou, Savvas; Marshburn, Tom; Dulchavsky, Scott A.

2002-01-01

Orthopedic fractures are a common injury in operational activities, injuries that often occur in isolated or hostile environments. Clinical ultrasound devices have become more user friendly and lighter allowing them to be easily transported with forward medical teams. The bone-soft tissue interface has a very large acoustic impedance, with a high reflectance that can be used to visualize breaks in contour including fractures. Herein reported is a case of an ulnar fracture that was quickly visualized in the early phase of a multi-system trauma resuscitation with a hand-held ultrasound device. The implications for operational medicine are discussed.

Ultrasound Improves Cricothyrotomy Success in Cadavers with Poorly Defined Neck Anatomy: A Randomized Control Trial.

PubMed

Siddiqui, Naveed; Arzola, Cristian; Friedman, Zeev; Guerina, Laarni; You-Ten, Kong Eric

2015-11-01

Misidentification of the cricothyroid membrane in a "cannot intubate-cannot oxygenate" situation can lead to failures and serious complications. The authors hypothesized that preprocedure ultrasound-guided identification of the cricothyroid membrane would reduce complications associated with cricothyrotomy. A group of 47 trainees were randomized to digital palpation (n = 23) and ultrasound (n = 24) groups. Cricothyrotomy was performed on human cadavers by using the Portex device (Smiths Medical, USA). Anatomical landmarks of cadavers were graded as follows: grade 1-easy = visual landmarks; 2-moderate = requires light palpation of landmarks; 3-difficult = requires deep palpation of landmarks; and 4-impossible = landmarks not palpable. Primary outcome was the complication rate as measured by the severity of injuries. Secondary outcomes were correct device placement, failure to cannulate, and insertion time. Ultrasound guidance significantly decreased the incidence of injuries to the larynx and trachea (digital palpation: 17 of 23 = 74% vs. ultrasound: 6 of 24 = 25%; relative risk, 2.88; 95% CI, 1.39 to 5.94; P = 0.001) and increased the probability of correct insertion by 5.6 times (P = 0.043) in cadavers with difficult and impossible landmark palpation (digital palpation 8.3% vs. ultrasound 46.7%). Injuries were found in 100% of the grades 3 to 4 (difficult-impossible landmark palpation) cadavers by digital palpation compared with only 33% by ultrasound (P < 0.001). The mean (SD) insertion time was significantly longer with ultrasound than with digital palpation (196.1 s [60.6 s] vs. 110.5 s [46.9 s]; P < 0.001). Preprocedure ultrasound guidance in cadavers with poorly defined neck anatomy significantly reduces complications and improves correct insertion of the airway device in the cricothyroid membrane.

Anterior Segment Morphology in Primary Angle Closure Glaucoma using Ultrasound Biomicroscopy

PubMed Central

Balakrishna, Nagalla

2017-01-01

Aim To evaluate the configuration of the anterior chamber angle quantitatively and study the morphological changes in the eye with ultrasound biomicroscopy (UBM) in primary angle closure glaucoma (PACG) patients after laser peripheral iridotomy (LPI). Materials and methods A total of 185 eyes of 185 PACG patients post-LPI and 126 eyes of 126 normal subjects were included in this prospective study. All subjects underwent complete ophthalmic evaluation, A-scan biometry, and UBM. The anterior segment and angle parameters were measured quantitatively and compared in both groups using Student’s t-test. Results The PACG patients had shorter axial length, shallower central anterior chamber depth anterior chamber depth (ACD), and anteriorly located lens when compared with normal subjects. Trabecular iris angle (TIA) was significantly narrow (5.73 ± 7.76°) in patients with PACG when compared with normal subjects (23.75 ± 9.38°). The angle opening distance at 500 pm from scleral spur (AOD 500), trabecular-ciliary process distance (TCPD), iris-ciliary process distance (ICPD), and iris-zonule distance (IZD) were significantly shorter in patients with PACG than in normal subjects (p < 0.0001). The iris lens angle (ILA), scleral-iris angle (SIA), and scleral-ciliary process angle (SCPA) were significantly narrower in patients with PACG than in normal subjects (p < 0.0001). The iris-lens contact distance (ILCD) was greater in PACG group than in normal (p = 0.001). Plateau iris was seen in 57/185 (30.8%) of the eyes. Anterior positioned ciliary processes were seen in 130/185 eyes (70.3%) of eyes. Conclusion In PACG patients, persistent apposition angle closure is common even after LPI, which could be due to anterior rotation of ciliary body and plateau iris and overcrowding of anterior segment due to shorter axial length and relative anterior lens position. How to cite this article: Mansoori T, Balakrishna N. Anterior Segment Morphology in Primary Angle Closure Glaucoma

A longitudinal study assessing lens thickness changes in the eye of the growing beagle using ultrasound scanning: relevance to age of dogs in regulatory toxicology studies.

PubMed

Maynard, Juliana; Sykes, Angela; Powell, Helen; Healing, Guy; Scott, Marietta; Holmes, Andrew; Ricketts, Sally-Ann; Stewart, Jane; Davis, Stewart

2014-12-01

The lens is formed in utero with new secondary lens fibres added as outer layers throughout life in a growth pattern characteristic of the species. This study examined the time course of beagle lens growth to better understand the optimal starting age of dogs for safety studies to support adult versus paediatric indications, and to assess the feasibility of non-invasively monitoring lens growth with high frequency ultrasound. Ultrasound scanning was performed in six female beagle dogs using the Vevo770. All dogs were imaged in B-mode using local anaesthetic but without sedation. Imaging was carried out every 2 weeks from 8 to 22 weeks of age and then monthly until 62 weeks of age. The dogs tolerated the procedure well. The lens was visible in all dogs and measuring the lens thickness with high frequency ultrasound demonstrated good analytical reproducibility [Root Mean Square (RMS) = 3.13%]. No differences between the left and right eye existed and lens thickness correlated with body weight. The highest weekly growth rate was before 12 weeks of age. A statistically significant difference between monthly thickness was detected until 42 weeks of age at which point growth reached a plateau. During the experiment, lenses grew by 29.7% reaching an average thickness of 6.4 mm ± 0.03. By 10 months of age (the typical age used for routine toxicological evaluation), beagles have reached a plateau in lens growth that is analogous to human adults. Where lens is a target organ of concern it is suggested that beagles under 6 months old may be a better model for determining paediatric safety. Copyright © 2014 John Wiley & Sons, Ltd.

[Evidence of lacrimal plugs via high resolution ultrasound].

PubMed

Tost, Frank H W; Darman, Jacques

2003-07-01

The practical value of high-frequency ultrasound (transducer frequency of 20 MHz) for studying lacrimal plugs positioned into canaliculi was proved. Twelve patients with twenty intracanalicular plugs and two punctum plugs were examined via high-frequency B-scan ultrasonography using 20 MHz transducer (model I3 Sacramento, USA). Detection and localisation of the intracanalicular plugs was made by a 20 MHz sector scanner. The ultrasound examinations were performed 1 - 24 month after the placement of lacrimal plugs. After patient's head positioning, the high-frequency ultrasound investigation was done via immersion fluid (2 % methylcellulose). All patients with dry eye treated by lacrimal plug implant showed echographic structure in the lacrimal canaliculus. In transversal echograms it was possible to image both canaliculi together when the lids were half-closed. Contrary to the normal state, it was not necessary to inject viscous fluid into the canaliculus. High-resolution ultrasound was able to differentiate the normal canaliculus from the findings after plug placement. The echograms can vary from one plug type to another. Highly reflective structures were found after the placement of silicone intracanalicular plugs, e. g. HERRICK-Plug. In contrast, the ultrasonic image taken through acrylic polymer intracanalicular plugs showed homogeneous small reflective inner structure, e. g. SMART-Plug. However, smooth and flat acoustic interface between acrylic polymer plug and the lacrimal canaliculus produced strong echoes. 20 MHz ultrasound seems to be well suited for the detection and localisation of intracanalicular plugs. By use of 20 MHz ultrasound scans it is possible to get high-quality images of the intracanalicular plug and around lacrimal canaliculus. Compared with UBM, the depth of penetration is much higher with negligible resolution. On the whole, we believe that 20 MHz ultrasound can become a useful tool for evaluating the placement of intracanalicular plugs

A new experimental device to evaluate eye ulcers using a multispectral electrical impedance technique

NASA Astrophysics Data System (ADS)

Bellotti, Mariela I.; Bast, Walter; Berra, Alejandro; Bonetto, Fabián J.

2011-07-01

We present a novel experimental technique to determine eye ulcers in animals using a spectral electrical impedance technique. We expect that this technique will be useful in dry eye syndrome. We used a sensor that is basically a platinum (Pt) microelectrode electrically insulated by glass from a cylindrical stainless steel counter-electrode. This sensor was applied to the naked eye of New Zealand rabbits (2.0-3.5 kg in weight). Whereas half of the eyes were normal (control), we applied to the remainder a few drops of 20% (v/v) alcohol to produce an ulcer in the eye. Using a multispectral electrical impedance system we measured ulcerated and control eyes and observed significant difference between normal and pathological samples. We also investigated the effects of different applied pressures and natural degradation of initially normal eyes as a function of time. We believe that this technique could be sufficiently sensitive and repetitive to help diagnose ocular surface diseases such as dry eye syndrome.

A new experimental device to evaluate eye ulcers using a multispectral electrical impedance technique.

PubMed

Bellotti, Mariela I; Bast, Walter; Berra, Alejandro; Bonetto, Fabián J

2011-07-01

We present a novel experimental technique to determine eye ulcers in animals using a spectral electrical impedance technique. We expect that this technique will be useful in dry eye syndrome. We used a sensor that is basically a platinum (Pt) microelectrode electrically insulated by glass from a cylindrical stainless steel counter-electrode. This sensor was applied to the naked eye of New Zealand rabbits (2.0-3.5 kg in weight). Whereas half of the eyes were normal (control), we applied to the remainder a few drops of 20% (v/v) alcohol to produce an ulcer in the eye. Using a multispectral electrical impedance system we measured ulcerated and control eyes and observed significant difference between normal and pathological samples. We also investigated the effects of different applied pressures and natural degradation of initially normal eyes as a function of time. We believe that this technique could be sufficiently sensitive and repetitive to help diagnose ocular surface diseases such as dry eye syndrome.

Upconverting device for enhanced recogntion of certain wavelengths of light

DOEpatents

Kross, Brian; McKIsson, John E; McKisson, John; Weisenberger, Andrew; Xi, Wenze; Zorn, Carl

2013-05-21

An upconverting device for enhanced recognition of selected wavelengths is provided. The device comprises a transparent light transmitter in combination with a plurality of upconverting nanoparticles. The device may a lens in eyewear or alternatively a transparent panel such as a window in an instrument or machine. In use the upconverting device is positioned between a light source and the eye(s) of the user of the upconverting device.

MO-FG-210-02: Implementation of Image-Guided Prostate HDR Brachytherapy Using MR-Ultrasound Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, B.

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real-time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR-ultrasound co-registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefitmore » from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy. Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR-ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.« less

Infant Eye-Tracking in the Context of Goal-Directed Actions

ERIC Educational Resources Information Center

Corbetta, Daniela; Guan, Yu; Williams, Joshua L.

2012-01-01

This paper presents two methods that we applied to our research to record infant gaze in the context of goal-oriented actions using different eye-tracking devices: head-mounted and remote eye-tracking. For each type of eye-tracking system, we discuss their advantages and disadvantages, describe the particular experimental setups we used to study…

Combined Ultrasound and MR Imaging to Guide Focused Ultrasound Therapies in the Brain

PubMed Central

Arvanitis, Costas D.; Livingstone, Margaret S.; McDannold, Nathan

2013-01-01

Purpose Several emerging therapies with potential for use in the brain harness effects produced by acoustic cavitation – the interaction between ultrasound and microbubbles either generated during sonication or introduced into the vasculature. Systems developed for transcranial MRI-guided focused ultrasound (MRgFUS) thermal ablation can enable their clinical translation, but methods for real-time monitoring and control are currently lacking. Acoustic emissions produced during sonication can provide information about the location, strength, and type of the microbubble oscillations within the ultrasound field, and they can be mapped in real-time using passive imaging approaches. Here, we tested whether such mapping can be achieved transcranially within a clinical brain MRgFUS system. Materials and Methods We integrated an ultrasound imaging array into the hemisphere transducer of the MRgFUS device. Passive cavitation maps were obtained during sonications combined with a circulating microbubble agent at 20 targets in the cingulate cortex in three macaques. The maps were compared with MRI-evident tissue effects. Results The system successfully mapped microbubble activity during both stable and inertial cavitation, which was correlated with MRI-evident transient blood-brain barrier disruption and vascular damage, respectively. The location of this activity was coincident with the resulting tissue changes within the expected resolution limits of the system. Conclusion While preliminary, these data clearly demonstrate, for the first time, that is possible to construct maps of stable and inertial cavitation transcranially, in a large animal model, and under clinically relevant conditions. Further, these results suggest that this hybrid ultrasound/MRI approach can provide comprehensive guidance for targeted drug delivery via blood-brain barrier disruption and other emerging ultrasound treatments, facilitating their clinical translation. We anticipate it will also prove to

Combined ultrasound and MR imaging to guide focused ultrasound therapies in the brain

NASA Astrophysics Data System (ADS)

Arvanitis, Costas D.; Livingstone, Margaret S.; McDannold, Nathan

2013-07-01

Several emerging therapies with potential for use in the brain, harness effects produced by acoustic cavitation—the interaction between ultrasound and microbubbles either generated during sonication or introduced into the vasculature. Systems developed for transcranial MRI-guided focused ultrasound (MRgFUS) thermal ablation can enable their clinical translation, but methods for real-time monitoring and control are currently lacking. Acoustic emissions produced during sonication can provide information about the location, strength and type of the microbubble oscillations within the ultrasound field, and they can be mapped in real-time using passive imaging approaches. Here, we tested whether such mapping can be achieved transcranially within a clinical brain MRgFUS system. We integrated an ultrasound imaging array into the hemisphere transducer of the MRgFUS device. Passive cavitation maps were obtained during sonications combined with a circulating microbubble agent at 20 targets in the cingulate cortex in three macaques. The maps were compared with MRI-evident tissue effects. The system successfully mapped microbubble activity during both stable and inertial cavitation, which was correlated with MRI-evident transient blood-brain barrier disruption and vascular damage, respectively. The location of this activity was coincident with the resulting tissue changes within the expected resolution limits of the system. While preliminary, these data clearly demonstrate, for the first time, that it is possible to construct maps of stable and inertial cavitation transcranially, in a large animal model, and under clinically relevant conditions. Further, these results suggest that this hybrid ultrasound/MRI approach can provide comprehensive guidance for targeted drug delivery via blood-brain barrier disruption and other emerging ultrasound treatments, facilitating their clinical translation. We anticipate that it will also prove to be an important research tool that will

Optical Detection of Ultrasound in Photoacoustic Imaging

PubMed Central

Dong, Biqin; Sun, Cheng; Zhang, Hao F.

2017-01-01

Objective Photoacoustic (PA) imaging emerges as a unique tool to study biological samples based on optical absorption contrast. In PA imaging, piezoelectric transducers are commonly used to detect laser-induced ultrasonic waves. However, they typically lack adequate broadband sensitivity at ultrasonic frequency higher than 100 MHz while their bulky size and optically opaque nature cause technical difficulties in integrating PA imaging with conventional optical imaging modalities. To overcome these limitations, optical methods of ultrasound detection were developed and shown their unique applications in photoacoustic imaging. Methods We provide an overview of recent technological advances in optical methods of ultrasound detection and their applications in PA imaging. A general theoretical framework describing sensitivity, bandwidth, and angular responses of optical ultrasound detection is also introduced. Results Optical methods of ultrasound detection can provide improved detection angle and sensitivity over significantly extended bandwidth. In addition, its versatile variants also offer additional advantages, such as device miniaturization, optical transparency, mechanical flexibility, minimal electrical/mechanical crosstalk, and potential noncontact PA imaging. Conclusion The optical ultrasound detection methods discussed in this review and their future evolution may play an important role in photoacoustic imaging for biomedical study and clinical diagnosis. PMID:27608445

[Trial of eye drops recognizer for visually disabled persons].

PubMed

Okamoto, Norio; Suzuki, Katsuhiko; Mimura, Osamu

2009-01-01

The development of a device to enable the visually disabled to differentiate eye drops and their dose. The new instrument is composed of a voice generator and a two-dimensional bar-code reader (LS9208). We designed voice outputs for the visually disabled to state when (number of times) and where (right, left, or both) to administer eye drops. We then determined the minimum bar-code size that can be recognized. After attaching bar-codes of the appropriate size to the lateral or bottom surface of the eye drops container, the readability of the bar-codes was compared. The minimum discrimination bar-code size was 6 mm high x 8.5 mm long. Bar-codes on the bottom surface could be more easily recognized than bar-codes on the side. Our newly-developed device using bar-codes enables visually disabled persons to differentiate eye drops and their doses.

Human Factors Engineering and testing for a wearable, long duration ultrasound system self-applied by an end user.

PubMed

Taggart, Rebecca; Langer, Matthew D; Lewis, George K

2014-01-01

One of the major challenges in the design of a new class of medical device is ensuring that the device will have a safe and effective user interface for the intended users. Human Factors Engineering addresses these concerns through direct study of how a user interacts with newly designed devices with unique features. In this study, a novel long duration, low intensity therapeutic ultrasound device is tested by 20 end users representative of the intended user population. Over 90% of users were able to operate the device successfully. The therapeutic ultrasound device was found to be reasonably safe and effective for the intended users, uses, and use environments.

Traffic control device conspicuity.

DOT National Transportation Integrated Search

2013-08-01

The conspicuity of a traffic control device (TCD) is defined as the probability that the device will be noticed. However, there is no agreed-upon measure of what constitutes being noticed. Various measures have been suggested, including eye fixations...

A Standard Mammography Unit - Standard 3D Ultrasound Probe Fusion Prototype: First Results.

PubMed

Schulz-Wendtland, Rüdiger; Jud, Sebastian M; Fasching, Peter A; Hartmann, Arndt; Radicke, Marcus; Rauh, Claudia; Uder, Michael; Wunderle, Marius; Gass, Paul; Langemann, Hanna; Beckmann, Matthias W; Emons, Julius

2017-06-01

The combination of different imaging modalities through the use of fusion devices promises significant diagnostic improvement for breast pathology. The aim of this study was to evaluate image quality and clinical feasibility of a prototype fusion device (fusion prototype) constructed from a standard tomosynthesis mammography unit and a standard 3D ultrasound probe using a new method of breast compression. Imaging was performed on 5 mastectomy specimens from patients with confirmed DCIS or invasive carcinoma (BI-RADS ™ 6). For the preclinical fusion prototype an ABVS system ultrasound probe from an Acuson S2000 was integrated into a MAMMOMAT Inspiration (both Siemens Healthcare Ltd) and, with the aid of a newly developed compression plate, digital mammogram and automated 3D ultrasound images were obtained. The quality of digital mammogram images produced by the fusion prototype was comparable to those produced using conventional compression. The newly developed compression plate did not influence the applied x-ray dose. The method was not more labour intensive or time-consuming than conventional mammography. From the technical perspective, fusion of the two modalities was achievable. In this study, using only a few mastectomy specimens, the fusion of an automated 3D ultrasound machine with a standard mammography unit delivered images of comparable quality to conventional mammography. The device allows simultaneous ultrasound - the second important imaging modality in complementary breast diagnostics - without increasing examination time or requiring additional staff.

Clinical applications of very high frequency ultrasound in ophthalmology

NASA Astrophysics Data System (ADS)

Silverman, Ronald H.; Coleman, D. Jackson; Reinstein, Dan Z.; Lizzi, Frederic L.

2004-05-01

The eye is ideally suited for diagnostic imaging with very high frequency (>35 MHz) ultrasound (VHFU) because of its peripheral location and cystic structure. VHFU allows high resolution visualization of pathologies affecting the anterior segment of the eye, including tumors, cysts, foreign bodies, and corneal pathologies. We developed a series of prototype instruments suitable for ophthalmic studies using both polymer and lithium niobate transducers, with digitization of radiofrequency echo data at up to 500 MHz. While initially using linear scan geometries, we subsequently developed an arc-shaped scan matched to the curvature of the 0.5-mm-thick cornea to circumvent the effect of specular deflection of the ultrasound beam produced by the corneas curved surface. This technique allowed us to obtain data across the entire cornea and determination of the thickness of each corneal layer, including the epithelium (approximately 50 microns in thickness) and the surgically induced interface produced in LASIK, the most common form of refractive surgery. By scanning in a series of meridians, and applying optimized signal processing strategies (deconvolution, analytic signal envelope determination), corneal pachymetric maps representing the local thickness of each layer can be generated and aid in diagnosis of surgically induced defects or refractive abnormalities.

Automated nystagmus analysis. [on-line computer technique for eye data processing

NASA Technical Reports Server (NTRS)

Oman, C. M.; Allum, J. H. J.; Tole, J. R.; Young, L. R.

1973-01-01

Several methods have recently been used for on-line analysis of nystagmus: A digital computer program has been developed to accept sampled records of eye position, detect fast phase components, and output cumulative slow phase position, continuous slow phase velocity, instantaneous fast phase frequency, and other parameters. The slow phase velocity is obtained by differentiation of the calculated cumulative position rather than the original eye movement record. Also, a prototype analog device has been devised which calculates the velocity of the slow phase component during caloric testing. Examples of clinical and research eye movement records analyzed with these devices are shown.

MR-guided focused ultrasound robot for performing experiments on large animals

NASA Astrophysics Data System (ADS)

Mylonas, N.; Damianou, C.

2011-09-01

Introduction: In this paper an experimental MRI-guided focused ultrasound robot for large animals is presented. Materials and methods: A single element spherically focused transducer of 4 cm diameter, focusing at 10 cm and operating at 1 MHz was used. A positioning device was developed in order to scan the ultrasound transducer for performing MR-guided focused ultrasound experiments in large animals such as pig, sheep and dog. The positioning device incorporates only MRI compatible materials such as piezoelectric motors, Acrylonitrile Butadiene Styrene (ABS) plastic, brass screws, and brass pulleys. The system is manufactured automatically using a rapid prototyping system. Results: The system was tested successfully in a number of animals for various tasks (creation of single lesions, creation of overlapping lesions, and MR compatibility). Conclusions: A simple, cost effective, portable positioning device has been developed which can be used in virtually any clinical MRI scanner since it can be sited on the scanner's table. The propagation of HIFU can be via a lateral or superior-inferior approach. This system has the potential to be marketed as a cost effective solution for performing experiments in small and large animals.

Ultrasound pregnancy

MedlinePlus

Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; Placenta previa - ultrasound; Multiple pregnancy - ultrasound; ...

Wireless ultrasound-powered biotelemetry for implants.

PubMed

Towe, Bruce C; Larson, Patrick J; Gulick, Daniel W

2009-01-01

A miniature piezoelectric receiver coupled to a diode is evaluated as a simple device for wireless transmission of bioelectric events to the body surface. The device converts the energy of a surface-applied ultrasound beam to a high frequency carrier current in solution. Bioelectrical currents near the implant modulate the carrier amplitude, and this signal is remotely detected and demodulated to recover the biopotential waveform. This technique achieves millivolt sensitivity in saline tank tests, and further attention to system design is expected to improve sensitivity.

Eye safety related to near infrared radiation exposure to biometric devices.

PubMed

Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

2011-03-01

Biometrics has become an emerging field of technology due to its intrinsic security features concerning the identification of individuals by means of measurable biological characteristics. Two of the most promising biometric modalities are iris and retina recognition, which primarily use nonionizing radiation in the infrared region. Illumination of the eye is achieved by infrared light emitting diodes (LEDs). Even if few LED sources are capable of causing direct eye damage as they emit incoherent light, there is a growing concern about the possible use of LED arrays that might pose a potential threat. Exposure to intense coherent infrared radiation has been proven to have significant effects on living tissues. The purpose of this study is to explore the biological effects arising from exposing the eye to near infrared radiation with reference to international legislation.

[Changes of axial dimensions of the eye during growth in emmetropia, myopia and hyperopia].

PubMed

Katuzny, Bartłomiej J; Koszewska-Kołodziejczak, Aleksandra

2005-01-01

The aim ot this study was to evaluate changes ot axial dimensions ot the eye during growth in emmetropia, myopia and hyperopia. We examined 183 children (363 eyes) aged 4 to 19 with emmetropia, myopia and hyperopia. All measurements were performed after cycloplegia with 1% tropicamidum (Polfa Warszawa). Total and corneal refraction was examined with autokeratorefractometer (Nikon NRK-8000). Then we used ultrasound biometer Ocuscan (Alcon, USA), to measure axial length of the eye, axial length of the vitreous cavity, axial dimension of the lens and axial depth of the anterior chamber. 1. Growth of the axial length of the emmetropic eyes is finished at the age of 12, in hyperopic eyes in the age of 11 and in myopic eyes growth is proportional until the age of 14 and then significantly accelerates. 2. Growth of the axial length is mainly caused by increasing axial length of vitreous cavity. A little role in human eye growth is also played by increasing depth of the anterior chamber. 3. Between 4 and 19 years old, mean cycloplegic axial dimension of the lens is slightly decreasing in emmetropic and hyperopic eyes, whereas in myopic eyes is constant.

Development towards compact nitrocellulose interferometric biochips for dry eye diagnosis based on MMP9, S100A6 and CST4 biomarkers using a Point-of-Care device

NASA Astrophysics Data System (ADS)

Santamaría, Beatriz; Laguna, María. Fe; López-Romero, David; López-Hernandez, A.; Sanza, F. J.; Lavín, A.; Casquel, R.; Maigler, M.; Holgado, M.

2018-02-01

A novel compact optical biochip based on a thin layer-sensing BICELL surface of nitrocellulose is used for in-situ labelfree detection of dry eye disease (DED). In this work the development of a compact biosensor that allows obtaining quantitative diagnosis with a limited volume of sample is reported. The designed sensors can be analyzed with an optical integrated Point-of-Care read-out system based on the "Increase Relative Optical Power" principle which enhances the performance and Limit of Detection. Several proteins involved with dry eye dysfunction have been validated as biomarkers. Presented biochip analyzes three of those biomarkers: MMP9, S100A6 and CST4. BICELLs based on nitrocellulose permit to immobilize antibodies for each biomarker recognition. The optical response obtained from the biosensor through the readout platform is capable to recognize specifically the desired proteins in the concentrations range for control eye (CE) and dry eye syndrome (DES). Preliminary results obtained will allow the development of a dry eye detection device useful in the area of ophthalmology and applicable to other possible diseases related to the eye dysfunction.

Raman Shifted Nd:YAG Class I Eye-Safe Laser Development 21 January 1986

NASA Astrophysics Data System (ADS)

Nichols, R. W.; Ng, W. K.

1986-07-01

Hughes Aircraft has been developing a hand-held eye-safe laser rangefinder fo1r the Army utilizing Stimulated Raman Scattering technology. The device uses the 2915 cm-1 vibrational mode of methane (CH4) to wavelength shift the Nd:YAG pump laser's 1.064 micron to an eye-safe 1.543 micron. The result is a lightweight BRH Class I eye-safe tactical device. A brief description of Raman wavelength shifting basics is followed by description of the Hughes system.

Prediction of hip fracture risk by quantitative ultrasound in more than 7000 Swiss women > or =70 years of age: comparison of three technologically different bone ultrasound devices in the SEMOF study.

PubMed

Krieg, Marc-Antoine; Cornuz, Jacques; Ruffieux, Christiane; Van Melle, Guy; Büche, Daniel; Dambacher, Maximilian A; Hans, Didier; Hartl, Florian; Häuselmann, Hansjorg J; Kraenzlin, Marius; Lippuner, Kurt; Neff, Maurus; Pancaldi, Pierro; Rizzoli, Rene; Tanzi, Franco; Theiler, Robert; Tyndall, Alan; Wimpfheimer, Claus; Burckhardt, Peter

2006-09-01

To compare the prediction of hip fracture risk of several bone ultrasounds (QUS), 7062 Swiss women > or =70 years of age were measured with three QUSs (two of the heel, one of the phalanges). Heel QUSs were both predictive of hip fracture risk, whereas the phalanges QUS was not. As the number of hip fracture is expected to increase during these next decades, it is important to develop strategies to detect subjects at risk. Quantitative bone ultrasound (QUS), an ionizing radiation-free method, which is transportable, could be interesting for this purpose. The Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk (SEMOF) study is a multicenter cohort study, which compared three QUSs for the assessment of hip fracture risk in a sample of 7609 elderly ambulatory women > or =70 years of age. Two QUSs measured the heel (Achilles+; GE-Lunar and Sahara; Hologic), and one measured the heel (DBM Sonic 1200; IGEA). The Cox proportional hazards regression was used to estimate the hazard of the first hip fracture, adjusted for age, BMI, and center, and the area under the ROC curves were calculated to compare the devices and their parameters. From the 7609 women who were included in the study, 7062 women 75.2 +/- 3.1 (SD) years of age were prospectively followed for 2.9 +/- 0.8 years. Eighty women reported a hip fracture. A decrease by 1 SD of the QUS variables corresponded to an increase of the hip fracture risk from 2.3 (95% CI, 1.7, 3.1) to 2.6 (95% CI, 1.9, 3.4) for the three variables of Achilles+ and from 2.2 (95% CI, 1.7, 3.0) to 2.4 (95% CI, 1.8, 3.2) for the three variables of Sahara. Risk gradients did not differ significantly among the variables of the two heel QUS devices. On the other hand, the phalanges QUS (DBM Sonic 1200) was not predictive of hip fracture risk, with an adjusted hazard risk of 1.2 (95% CI, 0.9, 1.5), even after reanalysis of the digitalized data and using different cut-off levels (1700 or 1570 m/s). In this elderly women

Transvaginal ultrasound

MedlinePlus

Endovaginal ultrasound; Ultrasound - transvaginal; Fibroids - transvaginal ultrasound; Vaginal bleeding - transvaginal ultrasound; Uterine bleeding - transvaginal ultrasound; Menstrual bleeding - transvaginal ultrasound; ...

Training Program for Cardiology Residents to Perform Focused Cardiac Ultrasound Examination with Portable Device.

PubMed

Siqueira, Vicente N; Mancuso, Frederico J N; Campos, Orlando; De Paola, Angelo A; Carvalho, Antonio C; Moises, Valdir A

2015-10-01

Training requirements for general cardiologists without echocardiographic expertise to perform focused cardiac ultrasound (FCU) with portable devices have not yet been defined. The objective of this study was to evaluate a training program to instruct cardiology residents to perform FCU with a hand-carried device (HCD) in different clinical settings. Twelve cardiology residents were subjected to a 50-question test, 4 lectures on basic echocardiography and imaging interpretation, the supervised interpretation of 50 echocardiograms and performance of 30 exams using HCD. After this period, they repeated the written test and were administered a practical test comprising 30 exams each (360 patients) in different clinical settings. They reported on 15 parameters and a final diagnosis; their findings were compared to the HCD exam of a specialist in echocardiography. The proportion of correct answers on the theoretical test was higher after training (86%) than before (51%; P = 0.001). The agreement was substantial among the 15 parameters analyzed (kappa ranging from 0.615 to 0.891; P < 0.001). The percentage of correct interpretation was lower for abnormal (75%) than normal (95%) items, for valve abnormalities (85%) compared to other items (92%) and for graded scale (87%) than for dichotomous (95%) items (P < 0.0001, for all). For the final diagnoses, the kappa value was higher than 0.941 (P < 0.001; 95% CI [0.914, 0.955]). The training proposed enabled residents to perform FCU with HCD, and their findings were in good agreement with those of a cardiologist specialized in echocardiography. © 2015, Wiley Periodicals, Inc.

4D Ultrasound - Medical Devices for Recent Advances on the Etiology of Cerebral Palsy

PubMed Central

Tomasovic, Sanja; Predojevic, Maja

2011-01-01

Children cerebral palsy (CCP) encompasses a group of nonprogessive and noninfectious conditions, which cause light, moderate, and severe deviations in neurological development. Diagnosis of CCP is set mostly by the age of 3 years. The fact that a large number of cerebral damage occurs prenatally and the fact that early intervention in cases of neurological damage is successful, prompted some researchers to explore the possibility of detecting neurologically damaged fetus in the uterus. This research was made possible thanks to the development of two-dimensional ultrasound technology in a real time, which enabled the display of the mobility of the fetus. Advancement of the ultrasound technology has enabled the development of 4D ultrasound where a spontaneous fetal movement can be observed almost in a real time. Estimate of the number and quality of spontaneous fetal movements and stitches on the head, the neurology thumb and a high palate were included in the prenatal neurological screening of the fetus. This raises the question, as to does the fetal behavior reflect, (which was revealed in 2D or 4D ultrasound), fetal neurological development in a manner that will allow the detection of the brain damage. PMID:23407920

Ultrasound cavitation versus cryolipolysis for non-invasive body contouring.

PubMed

Mahmoud ELdesoky, Mohamed Taher; Mohamed Abutaleb, Enas ELsayed; Mohamed Mousa, Gihan Samir

2015-08-24

The demand for non-surgical and non-invasive devices is continuous and increasing. Such devices have gradually gained ground in the reduction of localised fat and the improvement of body contouring. The study aimed to compare the effects of ultrasound cavitation and cryolipolysis on localised abdominal fat. In total, 60 participants with a body mass index (BMI) over 30 kg/m 2 , whose age ranged between 25 and 45 years, were included. The participants were randomly assigned to three groups of 20 each, using ultrasound cavitation and diet, cryolipolysis and diet, and diet only (the control group), respectively. Measures were bodyweight, BMI, waist circumference and suprailiac skinfold were measured at the beginning of the study and 2 months later. The three groups showed significant improvements in all measured variables after 2 months. There was no statistically significant difference in bodyweight or in BMI among the groups after treatment. However, the groups using ultrasound cavitation and cryolipolysis showed better post-treatment improvement than the diet-only group in waist circumference and suprailiac skinfold. There was no statistically significant difference post-treatment between the cavitation and cryolipolysis groups in waist circumference or suprailiac skinfold. Both ultrasound cavitation and cryolipolysis are safe and effective for the reduction of abdominal fat thickness and for abdominal contouring. © 2015 The Australasian College of Dermatologists.

Design Considerations and Performance of MEMS Acoustoelectric Ultrasound Detectors

PubMed Central

Wang, Zhaohui; Ingram, Pier; Greenlee, Charles L.; Olafsson, Ragnar; Norwood, Robert A.; Witte, Russell S.

2014-01-01

Most single-element hydrophones depend on a piezoelectric material that converts pressure changes to electricity. These devices, however, can be expensive, susceptible to damage at high pressure, and/or have limited bandwidth and sensitivity. We have previously described the acoustoelectric (AE) hydrophone as an inexpensive alternative for mapping an ultrasound beam and monitoring acoustic exposure. The device exploits the AE effect, an interaction between electrical current flowing through a material and a propagating pressure wave. Previous designs required imprecise fabrication methods using common laboratory supplies, making it difficult to control basic features such as shape and size. This study describes a different approach based on microelectromechanical systems (MEMS) processing that allows for much finer control of several design features. In an effort to improve the performance of the AE hydrophone, we combine simulations with bench-top testing to evaluate key design features, such as thickness, shape, and conductivity of the active and passive elements. The devices were evaluated in terms of sensitivity, frequency response, and accuracy for reproducing the beam pattern. Our simulations and experimental results both indicated that designs using a combination of indium tin oxide (ITO) for the active element and gold for the passive electrodes (conductivity ratio = ~20) produced the best result for mapping the beam of a 2.25-MHz ultrasound transducer. Also, the AE hydrophone with a rectangular dumbbell configuration achieved a better beam pattern than other shape configurations. Lateral and axial resolutions were consistent with images generated from a commercial capsule hydrophone. Sensitivity of the best-performing device was 1.52 nV/Pa at 500 kPa using a bias voltage of 20 V. We expect a thicker AE hydrophone closer to half the acoustic wavelength to produce even better sensitivity, while maintaining high spectral bandwidth for characterizing medical

Arthropod eye-inspired digital camera with unique imaging characteristics

NASA Astrophysics Data System (ADS)

Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

2014-06-01

In nature, arthropods have a remarkably sophisticated class of imaging systems, with a hemispherical geometry, a wideangle field of view, low aberrations, high acuity to motion and an infinite depth of field. There are great interests in building systems with similar geometries and properties due to numerous potential applications. However, the established semiconductor sensor technologies and optics are essentially planar, which experience great challenges in building such systems with hemispherical, compound apposition layouts. With the recent advancement of stretchable optoelectronics, we have successfully developed strategies to build a fully functional artificial apposition compound eye camera by combining optics, materials and mechanics principles. The strategies start with fabricating stretchable arrays of thin silicon photodetectors and elastomeric optical elements in planar geometries, which are then precisely aligned and integrated, and elastically transformed to hemispherical shapes. This imaging device demonstrates nearly full hemispherical shape (about 160 degrees), with densely packed artificial ommatidia. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. We have illustrated key features of operation of compound eyes through experimental imaging results and quantitative ray-tracing-based simulations. The general strategies shown in this development could be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

Incremental value of pocket-sized imaging device for bedside diagnosis of unilateral pleural effusions and ultrasound-guided thoracentesis

PubMed Central

Lisi, Matteo; Cameli, Matteo; Mondillo, Sergio; Luzzi, Luca; Zacà, Valerio; Cameli, Paolo; Gotti, Giuseppe; Galderisi, Maurizio

2012-01-01

OBJECTIVES The present study aimed to assess the additional value of a pocket-sized imaging device (PSID) as an adjunct to plain chest X-rays in the diagnosis of pleural effusion (PE), mainly for those requiring pleural thoracentesis. METHODS We performed a thoracic ultrasound examination using a PSID in 73 patients with an abnormal chest X-ray diagnostic for unilateral PE. Abundant PE was defined as an interpleural distance between the diaphragm and visceral pleura (VP) of ≥30 mm at the apex of the 50 mm bisector line of the costodiaphragmatic recess at end expiration. RESULTS According to PSID ultrasound evaluation, abundant PE was present in 46 patients (63%), while 27 (37%) patients showed the presence of mild PE or absence of PE. Thoracentesis was performed successfully and without procedure-induced complications in all 46 patients with abundant PE. Using the above-mentioned method, we obtained a high diagnostic accuracy (area under the curve = 0.99) and excellent sensitivity and specificity of 91.7 and 99.9%, respectively, to predict a PE >1000 ml, when VP was >6.3 cm. CONCLUSIONS PSID is a useful tool that may integrate and complete the physical examination, also providing additional information to chest X-ray in the clinical management of patients with suspected PE. PSID evaluation can also increase the effectiveness and safety of thoracentesis. PMID:22815326

Teaching enthesis ultrasound: experience of an ultrasound training workshop.

PubMed

Miguel, Cláudia; De Miguel, Eugenio; Batlle-Gualda, Enrique; Rejón, Eduardo; Lojo, Leticia

2012-12-01

To evaluate a standardised enthesis ultrasound training method, a workshop was conducted to train rheumatologists on enthesis ultrasound. After a theoretical session about ultrasound elementary enthesis lesions (changes in tendon architecture/thickness, bone proliferation/erosion, bursitis or Doppler signal), a reading exercise of 28 entheses' ultrasonographic images (plantar fasciae, Achilles, origin and insertion of patellar tendon) was completed. Participants scored through an electronic multiple-choice device with six possible lesions in each enthesis. To assess the adequacy and efficacy of the workshop, we explored the following: (1) subjective outcomes: a 12-item structured satisfaction questionnaire (graded 1-5 using Likert scale) and (2) objective outcomes of reliability: sensitivity (Se), specificity (Sp) and percentage of correctly classified cases (CC). Forty-nine participants attended the workshop. The satisfaction questionnaire demonstrated a 4.7 mean global value. The inter-reader Kappa reliability coefficient was moderate for the plantar fascia (0.47), Achilles tendon (0.47), and distal patellar tendons (0.50) and good for the proximal patellar tendon (0.63). The whole group means comparing to teachers' consensus were as follows: (a) plantar fascia: Se, 73.2%; Sp, 87.7%; CC, 83.3%; (b) Achilles: Se, 66.9%; Sp, 85.0%; CC, 79.5%; (c) distal patellar tendon: Se, 74.6%; Sp, 85.3%; CC, 82.1%; and (d) proximal patellar tendon: Se, 82.2%; Sp, 90.6%; CC, 88%. The proposed learning method seemed to be simple, easily performed, effective and well accepted by the target audience.

Ultrasound

MedlinePlus

... community Home > Pregnancy > Prenatal care > Ultrasound during pregnancy Ultrasound during pregnancy E-mail to a friend Please ... you. What are some reasons for having an ultrasound? Your provider uses ultrasound to do several things, ...

Microfocused ultrasound for skin tightening.

PubMed

MacGregor, Jennifer L; Tanzi, Elizabeth L

2013-03-01

The demand for noninvasive skin tightening procedures is increasing as patients seek safe and effective alternatives to aesthetic surgical procedures of the face, neck, and body. Over the past decade, radiofrequency and infrared laser devices have been popularized owing to their ability to deliver controlled heat to the dermis, stimulate neocollagenesis, and effect modest tissue tightening with minimal recovery. However, these less invasive approaches are historically associated with inferior efficacy so that surgery still remains the treatment of choice to address moderate to severe tissue laxity. Microfocused ultrasound was recently introduced as a novel energy modality for transcutaneous heat delivery that reaches the deeper subdermal connective tissue in tightly focused zones at consistent programmed depths. The goal is to produce a deeper wound healing response at multiple levels with robust collagen remodeling and a more durable clinical response. The Ulthera device (Ulthera, Inc, Meza, AZ), with refined microfocused ultrasound technology, has been adapted specifically for skin tightening and lifting with little recovery or risk of complications since its introduction in 2009. As clinical parameters are studied and optimized, enhanced efficacy and consistency of clinical improvement is expected.

Ultrasonography and optical low-coherence interferometry compared in the chicken eye.

PubMed

Penha, Alexandra Marcha; Burkhardt, Eva; Schaeffel, Frank; Feldkaemper, Marita P

2012-06-01

To compare ocular biometry [anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL)] using A-scan ultrasonography and optical low-coherence interferometry (OLCI) in the chicken eye. Two-week-old chicks (n = 42) were measured. Bland-Altman plots and repeatability and correlation analyses were calculated for both methods. There was a high correlation between both methods for ACD (r = 0.6144, p < 0.0001), VCD (r = 0.9595, p < 0.0001), and AL (r = 0.9290, p < 0.0001) but not for LT (r = 0.1604, p = 0.144). Measurements by OLCI were more consistent (smaller coefficients of variation and higher intraclass correlation). Bland-Altman plots showed that ultrasound provided larger values for LT, VCD, and AL but not for ACD [differences between ultrasound and OLCI (mean ± SD): ACD = -0.11 ± 0.12 mm; LT = 0.10 ± 0.09 mm; VCD = 0.25 ± 0.08 mm; AL = 0.50 ± 0.16 mm]. A high correlation between both techniques was found for three of the four parameters (ACD, VCD, and AL). However, as the absolute values were different, both techniques cannot replace each other mainly because (1) one is non-contact and the other contact and can induce a minor indentation of the cornea and (2) each device uses different types of waves that cross the ocular interfaces differently. While consistency and repeatability were better by OLCI, a disadvantage is that, different from humans, it can only be used in anesthetized chicks.

Ultrasound ionization of biomolecules.

PubMed

Wu, Chen-I; Wang, Yi-Sheng; Chen, Nelson G; Wu, Chung-Yi; Chen, Chung-Hsuan

2010-09-15

To date, mass spectrometric analysis of biomolecules has been primarily performed with either matrix-assisted laser desorption/ionization (MALDI) or electrospray ionization (ESI). In this work, ultrasound produced by a simple piezoelectric device is shown as an alternative method for soft ionization of biomolecules. Precursor ions of proteins, saccharides and fatty acids showed little fragmentation. Cavitation is considered as a primary mechanism for the ionization of biomolecules. Copyright 2010 John Wiley & Sons, Ltd.

EDITORIAL: The Eye and The Chip 2008 The Eye and The Chip 2008

NASA Astrophysics Data System (ADS)

Rizzo, Joseph F.; O'Malley, Edward R.; Hessburg, Philip C.

2009-06-01

Over the course of the past decade, The Eye and The Chip world congress on visual neuro-prosthetic devices has become a premier meeting for those who believe that 'artificial' vision will one day be used to improve the quality of life of visually impaired patients. Although substantial progress has been made, there are numerous unresolved issues, like the preferred methods for wireless communication, placement of devices, and materials and design among others. The Eye and The Chip meeting of 2008, held in Detroit on 12-14 June 2008, provided important new information about these and other important topics, and thus served to advance this field of scientific research. From a research seedling a decade ago to the crowd of superb presentations in Detroit last June, a very real sense of justifiable optimism has developed. The prospects of artificial vision are no longer remote. Many of the researchers expressed confidence that implantable devices will provide the hoped-for level of vision to justify their widespread use in the future. The often dramatic successes of cochlear implants continues to provide credence that artificial stimulation of nerve tissue is a plausible strategy to restore vision. The Eye and The Chip 2008 attracted researchers from four continents (North America, Europe, Asia and Australia). The meeting also benefited from the attendance and presentations by representatives of the FDA, who have been present for all The Eye and The Chip meetings. The 2008 meeting was also enhanced by the inclusion of a new and related scientific field that shares the goal of restoring vision to the blind—the field of molecular restoration of retinal function by insertion of channelrhodopsin. Just as the field of ophthalmology went from Ridley's primitive intraocular lens replacement to implants useful in virtually every cataract patient in one surgeon's clinical lifetime, the field of retinal prostheses seems to be following a very similar trajectory. Likewise, the

Ultrasound comparison of external and internal neck anatomy with the LMA Unique.

PubMed

Lee, Steven M; Wojtczak, Jacek A; Cattano, Davide

2017-12-01

Internal neck anatomy landmarks and their relation after placement of an extraglottic airway devices have not been studied extensively by the use of ultrasound. Based on our group experience with external landmarks as well as internal landmarks evaluation with other techniques, we aimed use ultrasound to analyze the internal neck anatomy landmarks and the related changes due to the placement of the Laryngeal Mask Airway Unique. Observational pilot investigation. Non-obese adult patients with no evidence of airway anomalies, were recruited. External neck landmarks were measured based on a validated and standardized method by tape. Eight internal anatomical landmarks, reciprocal by the investigational hypothesis to the external landmarks, were also measured by ultrasound guidance. The internal landmarks were re-measured after optimal placement and inflation of the extraglottic airway devices cuff Laryngeal Mask Airway Unique. Six subjects were recruited. Ultrasound measurements of hyoid-mental distance, thyroid-cricoid distance, thyroid height, and thyroid width were found to be significantly ( p < 0.05) overestimated using a tape measure. Sagittal neck landmark distances such as thyroid height, sternal-mental distance, and thyroid-cricoid distance significantly decreased after placement of the Laryngeal Mask Airway Unique. The laryngeal mask airway Unique resulted in significant changes in internal neck anatomy. The induced changes and respective specific internal neck anatomy landmarks could help to design devices that would modify their shape accordingly to areas of greatest displacement. Also, while external neck landmark measurements overestimate their respective internal neck landmarks, as we previously reported, the concordance of each measurement and their respective conversion factor could continue to be of help in sizing extraglottic airway devices. Due to the pilot nature of the study, more investigations are warranted.

A Multifunctional Bimetallic Molecular Device for Ultrasensitive Detection, Naked-Eye Recognition, and Elimination of Cyanide Ions.

PubMed

Chow, Cheuk-Fai; Ho, Pui-Yu; Wong, Wing-Leung; Gong, Cheng-Bin

2015-09-07

A new bimetallic Fe(II) -Cu(II) complex was synthesized, characterized, and applied as a selective and sensitive sensor for cyanide detection in water. This complex is the first multifunctional device that can simultaneously detect cyanide ions in real water samples, amplify the colorimetric signal upon detection for naked-eye recognition at the parts-per-million (ppb) level, and convert the toxic cyanide ion into the much safer cyanate ion in situ. The mechanism of the bimetallic complex for high-selectivity recognition and signaling toward cyanide ions was investigated through a series of binding kinetics of the complex with different analytes, including CN(-) , SO4 (2-) , HCO3 (-) , HPO4 (2-) , N3 (-) , CH3 COO(-) , NCS(-) , NO3 (-) , and Cl(-) ions. In addition, the use of the indicator/catalyst displacement assay (ICDA) is demonstrated in the present system in which one metal center acts as a receptor and inhibitor and is bridged to another metal center that is responsible for signal transduction and catalysis, thus showing a versatile approach to the design of new multifunctional devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prenatal diagnosis of bilateral anophthalmia by 3D "reverse face" view ultrasound and magnetic resonance imaging.

PubMed

Araujo Júnior, Edward; Kawanami, Tatiana Emy; Nardozza, Luciano Marcondes Machado; Milani, Hérbene José Figuinha; Oliveira, Patrícia Soares; Moron, Antonio Fernandes

2012-12-01

Primary anophthalmia is a rare congenital malformation that affects 0.6/10,000 liveborn infants. It is usually associated with central nervous system malformations, aneuploidies, cytomegalovirus infection and mental retardation and it can also be part of genetic conditions such as Fraser, Goltz, Goldenhar, Waardenburg and Lenz syndromes. Neonatal prognosis depends on whether anophthalmia is an isolated malformation, or it is associated with other defects or part of a syndrome. A healthy 43-year-old woman, G4 P3 with three previous healthy children, was referred to our clinic for a routine obstetric ultrasound at 28 weeks' gestation. The fetal eye globes and lenses could not be seen on two-dimensional (2D) ultrasound, which led to the diagnosis of bilateral congenital anophthalmia. No other fetal malformations were detected. At 30 weeks' gestation, a three-dimensional (3D) ultrasound was performed using the rendering mode and "reverse face" view. Using this technique, the absence of both eye globes could be clearly seen through a "slit". 3D-ultrasound allowed the parents to better understand their child's problem and possible postnatal implications. Fetal magnetic resonance imaging (MRI) was also performed, to study the fetal cortex in more detail. This exam revealed right cerebral hemisphere sulci and gyri hypoplasia. At 41 1/7 weeks, she went into spontaneous labor and delivered vaginally a 3525 g male infant with Apgar scores of 9 and 10. Postnatal exams confirmed bilateral congenital anophthalmia. This is the first case report in the literature of prenatal diagnosis of bilateral anophthalmia using 3D "reverse face" view ultrasound and MRI. Copyright © 2012. Published by Elsevier B.V.

QUS devices for assessment of osteoporosis

NASA Astrophysics Data System (ADS)

Langton, Christian

2002-05-01

The acronym QUS (Quantitative Ultrasound) is now widely used to describe ultrasound assessment of osteoporosis, a disease primarily manifested by fragility fractures of the wrist and hip along with shortening of the spine. There is currently available a plethora of commercial QUS devices, measuring various anatomic sites including the heel, finger, and tibia. Largely through commercial rather than scientific drivers, the parameters reported often differ significantly from the two fundamental parameters of velocity and attenuation. Attenuation at the heel is generally reported as BUA (broadband ultrasound attenuation, the linearly regressed increase in attenuation between 200 and 600 kHz). Velocity derivatives include bone, heel, TOF, and AdV. Further, velocity and BUA parameters may be mathematically combined to provide proprietary parameters including ``stiffness'' and ``QUI.'' In terms of clinical utility, the situation is further complicated by ultrasound being inherently dependent upon ``bone quality'' (e.g., structure) in addition to ``bone quantity'' (generally expressed as BMD, bone mineral density). Hence the BMD derived WHO criteria for osteoporosis and osteopenia may not be directly applied to QUS. There is therefore an urgent need to understand the fundamental dependence of QUS parameters, to perform calibration and cross-correlation studies of QUS devices, and to define its clinical utility.

A dual-mode hemispherical sparse array for 3D passive acoustic mapping and skull localization within a clinical MRI guided focused ultrasound device

NASA Astrophysics Data System (ADS)

Crake, Calum; Brinker, Spencer T.; Coviello, Christian M.; Livingstone, Margaret S.; McDannold, Nathan J.

2018-03-01

Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound (MRgFUS) devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner. The array is constructed from 5  ×  0.4 mm piezoceramic disc elements arranged in pseudorandom fashion on a low-profile laser-cut acrylic frame designed to fit between the therapeutic elements of a 230 kHz InSightec ExAblate 4000 transducer. By exploiting thickness and radial resonance modes of the piezo discs the array is capable of both B-mode imaging at 5 MHz for skull localization, as well as passive reception at the second harmonic of the therapy array for detection of cavitation and 3D passive acoustic imaging. In active mode, the array was able to perform B-mode imaging of a human skull, showing the outer skull surface with good qualitative agreement with MR imaging. Extension to 3D showed the array was able to locate the skull within  ±2 mm/2° of reference points derived from MRI, which could potentially allow registration of a patient to the therapy system without the expense of real-time MRI. In passive mode, the array was able to resolve a point source in 3D within a  ±10 mm region about each axis from the focus, detect cavitation (SNR ~ 12 dB) at burst lengths from 10 cycles to continuous wave, and produce 3D acoustic maps in a flow phantom. Finally, the array was used to detect and map cavitation associated with microbubble activity in the brain in nonhuman primates.

Endoscopic ultrasound-guided biliary drainage

PubMed Central

Chavalitdhamrong, Disaya; Draganov, Peter V

2012-01-01

Endoscopic ultrasound (EUS)-guided biliary drainage has emerged as a minimally invasive alternative to percutaneous and surgical interventions for patients with biliary obstruction who had failed endoscopic retrograde cholangiopancreatography (ERCP). EUS-guided biliary drainage has become feasible due to the development of large channel curvilinear therapeutic echo-endoscopes and the use of real-time ultrasound and fluoroscopy imaging in addition to standard ERCP devices and techniques. EUS-guided biliary drainage is an attractive option because of its minimally invasive, single step procedure which provides internal biliary decompression. Multiple investigators have reported high success and low complication rates. Unfortunately, high quality prospective data are still lacking. We provide detailed review of the use of EUS for biliary drainage from the perspective of practicing endoscopists with specific focus on the technical aspects of the procedure. PMID:22363114

Ultrasound-guided near-infrared spectroscopy for brain functional study: feasibility analysis and preliminary work

NASA Astrophysics Data System (ADS)

Xu, Ronald; Qiang, Bo; Liu, Jun

2005-04-01

Recent advances in diffuse optical imaging and spectroscopy (DOIS) allow the noninvasive measurement of local changes in cerebral oxygenation and hemodynamics. Available DOIS devices fall into three categories: time domain (TD), frequency domain (FD) and continuous wave (CW). The TD and FD devices have potential for high spatial resolution, high temporal resolution and high accuracy measurement, but the instrument cost and the hardware size prevent their wide clinical application. Furthermore, the presence of the low scattering cerebrospinal fluid layer (CSF) and its thickness variation during motion challenges quantitative, continuous monitoring of the cortex layer oxygenation and blood content. MRI has been used to provide a priori knowledge of the head anatomy that helps the NIR image reconstruction. However, the technology is expensive and lacks portability. This paper proposes a method that combines the accuracy of a TD/FD system and the portability of a CW device. With the optical baseline measured by a TD or FD device and the layer thickness characterized by an ultrasound transducer, a conventional CW system may be able to quantify the cortex layer optical absorption with high accuracy. In this paper, the feasibility of using ultrasound guided CW spectroscopy to monitor brain activities was studied on a multi layer head model using Monte Carlo simulation and order of magnitude analysis. A forward algorithm based on diffuse approximation and 2D Fourier Transform was used to optimize the source detector separation. Both analytical and neuron network approaches were developed for inverse calculation of the cortex layer absorption in real time. An ultrasound transducer was used to monitor the thickness of different layers surrounding the cerebral cortex. The concept of ultrasound guided CW spectroscopy was demonstrated by numerical simulation on a 2 layer head model and the use of the ultrasound transducer for layer thickness characterization was verified by

Piezoelectric Micromachined Ultrasound Transducer (PMUT) Arrays for Integrated Sensing, Actuation and Imaging

PubMed Central

Qiu, Yongqiang; Gigliotti, James V.; Wallace, Margeaux; Griggio, Flavio; Demore, Christine E. M.; Cochran, Sandy; Trolier-McKinstry, Susan

2015-01-01

Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed. PMID:25855038

Piezoelectric micromachined ultrasound transducer (PMUT) arrays for integrated sensing, actuation and imaging.

PubMed

Qiu, Yongqiang; Gigliotti, James V; Wallace, Margeaux; Griggio, Flavio; Demore, Christine E M; Cochran, Sandy; Trolier-McKinstry, Susan

2015-04-03

Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed.

Duplex ultrasound

MedlinePlus

Vascular ultrasound; Peripheral vascular ultrasound ... A duplex ultrasound combines: Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures. Doppler ultrasound: This ...

An Assessment of Iterative Reconstruction Methods for Sparse Ultrasound Imaging

PubMed Central

Valente, Solivan A.; Zibetti, Marcelo V. W.; Pipa, Daniel R.; Maia, Joaquim M.; Schneider, Fabio K.

2017-01-01

Ultrasonic image reconstruction using inverse problems has recently appeared as an alternative to enhance ultrasound imaging over beamforming methods. This approach depends on the accuracy of the acquisition model used to represent transducers, reflectivity, and medium physics. Iterative methods, well known in general sparse signal reconstruction, are also suited for imaging. In this paper, a discrete acquisition model is assessed by solving a linear system of equations by an ℓ1-regularized least-squares minimization, where the solution sparsity may be adjusted as desired. The paper surveys 11 variants of four well-known algorithms for sparse reconstruction, and assesses their optimization parameters with the goal of finding the best approach for iterative ultrasound imaging. The strategy for the model evaluation consists of using two distinct datasets. We first generate data from a synthetic phantom that mimics real targets inside a professional ultrasound phantom device. This dataset is contaminated with Gaussian noise with an estimated SNR, and all methods are assessed by their resulting images and performances. The model and methods are then assessed with real data collected by a research ultrasound platform when scanning the same phantom device, and results are compared with beamforming. A distinct real dataset is finally used to further validate the proposed modeling. Although high computational effort is required by iterative methods, results show that the discrete model may lead to images closer to ground-truth than traditional beamforming. However, computing capabilities of current platforms need to evolve before frame rates currently delivered by ultrasound equipments are achievable. PMID:28282862

Ultrasound, histopathological, and genetic features of uveal melanoma in a Mexican-Mestizo population.

PubMed

Delgado, S; Rodriguez Reyes, A; Mora Rios, L; Dueñas-González, A; Taja-Chayeb, L; Moragrega Adame, E

2018-01-01

To describe the ultrasound, histopathological and genetic characteristics of uveal melanoma in a Mexican-Mestizo population. A total of 39 enucleated eyes with a histopathological diagnosis of uveal melanoma were assessed by describing the clinical findings, and ultrasound, histopathological and genetic features. A high correlation was observed between tumour height measurement using ultrasound and histopathology. In our cases, tumour size and reflectivity were higher compared with those reported in the literature. The preliminary data on the molecular assessment of the tumours show the presence of an unreported polymorphism (T>C IVS5+34) and one sample with GNAQ mutation (A>C CAA>CCA Gln 209 Pro). Ultrasound is a reliable method to identify the size of the tumour. Furthermore, knowledge of the molecular mechanisms promises new perspectives for the development of new targeted therapeutics. Fortunately this leads to progress in the treatment of patients with metastatic disease or prevents it in those at high risk. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Ultrasound and MRI of Pediatric Ocular Masses with Histopathologic Correlation

PubMed Central

Brennan, Rachel C.; Wilson, Matthew W.; Kaste, Sue; Helton, Kathleen J.; McCarville, M. Beth

2012-01-01

We review our experience with unusual ocular pathologies mimicking retinoblastoma that were referred to our institution over the past two decades. After presenting the imaging anatomy of the normal eye, we discuss pertinent clinical and pathological features, and illustrate the ultrasound and magnetic resonance imaging appearance of retinoblastoma, medulloepithelioma, uveal melanoma, persistent fetal vasculature, Coats disease, corneal dermoid, retinal dysplasia and toxocara granuloma. Features useful in discriminating between these entities are emphasized. PMID:22466750

SU-E-T-16: A Comparison of Expected Dwell Times and Dose Variations for NAMD Patients Treated with An Episcleral Brachytherapy Device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, R; Patel, P; Balaggan, K

2015-06-15

Purpose: To evaluate the variations in dwell times and doses expected when using an episcleral brachytherapy device for treatment of neovascular agerelated macular degeneration (n-AMD) based on accurate imaging modalities Methods: Data from 40 eyes from 40 subjects with known n- AMD acquired through the Distance of Choroid Study (DOCS) conducted at Moorfields Eye Hospital was used to determine the target depth; the distance from the outer scleral surface of the eye, through the choroid, to the apex of the choroidal neovascularization (CNV). Each subject underwent, in triplicate, enhanced-depth Spectral Domain Optical Coherence Tomography (SD-OCT), Swept Source Optical Coherence Tomography,more » (SS-OCT) and Ocular Ultrasound (O-US). These data are the most comprehensive and accurate measurements of the dimensions of the CNV and adjacent layers of the eye for this cohort of patients. During treatment of n-AMD, patients receive a dose of 24Gy to the apex at the target depth. Using the percentage depth dose for a Sr-90 episcleral brachytherapy device, dwell times and doses to the apex were computed to determine the expected variations. Results: The mean target depth and the 95% confidence interval (CI) determined by combining O-US with SD-OCT were 1326 (956,1696)µm and with SS-OCT were 1332 (970,1693)µm. The calculated corresponding mean dwell times and 95% (CI) were 334 (223,445)s and 335 (226,445)s for SD-OCT and SS-OCT determined depths, respectively. The corresponding mean apex dose and 95% (CI) were 24 (35.9,18.0)Gy (SD-OCT) and 24 (35.6,18.1)Gy (SS-OCT). Conclusion: For episcleral brachytherapy treatment of n-AMD, using a patient population average target depth for treatment planning is inadequate, resulting in dose variations of a factor of approximately two over the 95% CI and larger variations for a nontrivial segment of the population. Each patient should have individualized imaging studies to determine the target depth for use in the dwell time

Exploiting spatial degrees of freedom for high data rate ultrasound communication with implantable devices

NASA Astrophysics Data System (ADS)

Wang, Max L.; Arbabian, Amin

2017-09-01

We propose and demonstrate an ultrasonic communication link using spatial degrees of freedom to increase data rates for deeply implantable medical devices. Low attenuation and millimeter wavelengths make ultrasound an ideal communication medium for miniaturized low-power implants. While a small spectral bandwidth has drastically limited achievable data rates in conventional ultrasonic implants, a large spatial bandwidth can be exploited by using multiple transducers in a multiple-input/multiple-output system to provide spatial multiplexing gain without additional power, larger bandwidth, or complicated packaging. We experimentally verify the communication link in mineral oil with a transmitter and a receiver 5 cm apart, each housing two custom-designed mm-sized piezoelectric transducers operating at the same frequency. Two streams of data modulated with quadrature phase-shift keying at 125 kbps are simultaneously transmitted and received on both channels, effectively doubling the data rate to 250 kbps with a measured bit error rate below 10-4. We also evaluate the performance and robustness of the channel separation network by testing the communication link after introducing position offsets. These results demonstrate the potential of spatial multiplexing to enable more complex implant applications requiring higher data rates.

Ultrasound monitoring of inter-knee distances during gait.

PubMed

Lai, Daniel T H; Wrigley, Tim V; Palaniswami, M

2009-01-01

Knee osteoarthritis is an extremely common, debilitating disease associated with pain and loss of function. There is considerable interest in monitoring lower limb alignment due to its close association with joint overload leading to disease progression. The effects of gait modifications that can lower joint loading are of particular interest. Here we describe an ultrasound-based system for monitoring an important aspect of dynamic lower limb alignment, the inter-knee distance during walking. Monitoring this gait parameter should facilitate studies in reducing knee loading, a primary risk factor of knee osteoarthritis progression. The portable device is composed of an ultrasound sensor connected to an Intel iMote2 equipped with Bluetooth wireless capability. Static tests and calibration results show that the sensor possesses an effective beam envelope of 120 degrees, with maximum distance errors of 10% at the envelope edges. Dynamic walking trials reveal close correlation of inter-knee distance trends between that measured by an optical system (Optotrak Certus NDI) and the sensor device. The maximum average root mean square error was found to be 1.46 cm. Future work will focus on improving the accuracy of the device.

Advancements in the Design and Fabrication of Ultrasound Transducers for Extreme Temperatures

NASA Astrophysics Data System (ADS)

Bosyj, Christopher

An ultrasound transducer for operation from room temperature to 800 °C is developed. The device includes a lithium niobate piezoelectric crystal, a porous zirconia attenuative backing layer, and a quarter wavelength matching layer. The manufacturing procedure for porous zirconia is optimized by adjusting pore size and forming pressure to yield good acoustic performance and mechanical integrity. Several acoustic coupling methods are evaluated. A novel silver-copper braze and an aluminum-based braze are found to be suitable at elevated temperatures. Several materials are evaluated for their performance as a quarter wavelength matching layer in the transducer stack. The use of either a nickel-chromium or stainless steel matching layer is established in place of ceramic components. Equipment limitations prevent evaluation at 800 °C, though ultrasound transmission is theoretically achievable with the devices established by this study. Reliable high-amplitude, wide-bandwidth ultrasound transmission is achieved from room temperature to 600 °C with two transducer variants.

Towards Wearable A-Mode Ultrasound Sensing for Real-Time Finger Motion Recognition.

PubMed

Yang, Xingchen; Sun, Xueli; Zhou, Dalin; Li, Yuefeng; Liu, Honghai

2018-06-01

It is evident that surface electromyography (sEMG) based human-machine interfaces (HMI) have inherent difficulty in predicting dexterous musculoskeletal movements such as finger motions. This paper is an attempt to investigate a plausible alternative to sEMG, ultrasound-driven HMI, for dexterous motion recognition due to its characteristic of detecting morphological changes of deep muscles and tendons. A multi-channel A-mode ultrasound lightweight device is adopted to evaluate the performance of finger motion recognition; an experiment is designed for both widely acceptable offline and online algorithms with eight able-bodied subjects employed. The experiment result presents that the offline recognition accuracy is up to 98.83% ± 0.79%. The real-time motion completion rate is 95.4% ± 8.7% and online motion selection time is 0.243 ± 0.127 s. The outcomes confirm the feasibility of A-mode ultrasound based wearable HMI and its prosperous applications in prosthetic devices, virtual reality, and remote manipulation.

Relationship between relative lens position and appositional closure in eyes with narrow angles.

PubMed

Otori, Yasumasa; Tomita, Yuki; Hamamoto, Ayumi; Fukui, Kanae; Usui, Shinichi; Tatebayashi, Misako

2011-03-01

To investigate the relationship between relative lens position (RLP) and appositional closure in eyes with narrow angles. Ultrasound biomicroscopy (UBM) was used to measure anterior chamber depth (ACD) and lens thickness (LT), and the IOLMaster to measure axial length (AL). The number of quadrants with appositional closure was assessed by UBM under dark conditions. The RLP was calculated thus: RLP = 10 × (ACD + 0.5 LT) /AL. This study comprised 30 consecutive patients (30 eyes) with narrow-angle eyes defined as Shaffer grade 2 or lower and without peripheral anterior synechiae (24 women, 6 men; mean age ± SD, 67.3 ± 10.4 years; range, 42-87 years). Under dark conditions, 66.7% of the eyes with narrow angles showed appositional closure in at least one quadrant. Of the various ocular biometric parameters, only the RLP significantly decreased with appositional closure in at least one quadrant (P = 0.005). A decrease in the RLP can be predictive of appositional closure for narrow-angle eyes under dark conditions.

Application of a wide-field phantom eye for optical coherence tomography and reflectance imaging.

PubMed

Corcoran, Anthony; Muyo, Gonzalo; van Hemert, Jano; Gorman, Alistair; Harvey, Andrew R

2015-12-15

Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R. J. Opt. Soc. Am. A , 1985, 2 .] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for a [Formula: see text] external FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and Optos OCT SLO and use the phantom to provide an insight into some of the challenges of wide-field OCT.

Application of a wide-field phantom eye for optical coherence tomography and reflectance imaging

NASA Astrophysics Data System (ADS)

Corcoran, Anthony; Muyo, Gonzalo; van Hemert, Jano; Gorman, Alistair; Harvey, Andrew R.

2015-12-01

Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R. J. Opt. Soc. Am. A, 1985, 2.] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for a ? external FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and Optos OCT SLO and use the phantom to provide an insight into some of the challenges of wide-field OCT.

Association between FASN gene polymorphisms ultrasound carcass traits and intramuscular fat in Qinchuan cattle.

PubMed

Raza, Sayed Haidar Abbas; Gui, Linsheng; Khan, Rajwali; Schreurs, Nicola M; Xiaoyu, Wang; Wu, Sen; Mei, Chugang; Wang, Li; Ma, Xueyao; Wei, Dawei; Guo, Hongfang; Zhang, Song; Wang, Xingping; Kaleri, Hubdar Ali; Zan, Linsen

2018-03-01

Fatty acid synthase (FASN) is an enzyme involved with fat deposition and fatty acid composition in cattle. This study was conducted to detect single nucleotide polymorphisms (SNPs) of the FASN gene and explore their relationships with ultrasound carcass traits in order to assess the potential use of the FASN gene for the breeding selection of Qinchuan cattle for desirable carcass traits. The frequencies of SNP g.12740C>T, g.13192T>C and g.13232C>T were identified in 525 individual Qinchuan cattle which were also assessed for backfat depth, eye muscle area and intramuscular fat by ultrasound. According to the PIC values, g.13192T>C possessed an intermediate polymorphism (0.25T, g.12740C>T possessed low polymorphism (PIC<0.25). Chi-square tests showed that g.13192T>C were in Hardy-Weinberg disequilibrium (c2ultrasound carcass traits. The H 2 H 2 diplotypes had a greater back fat depth than H 1 H 1 , H 1 H 4 and H 1 H 2 (P<0.01). The TT genotype at g.13192T>C was associated with a greater eye muscle area and the TT genotype at g.13232C>T was associated with greater intramuscular fat. When these genotypes were combined there was no difference in eye muscle area and intramuscular fat between the diplotypes. The H 2 H 2 diplotype was associated with carcass traits that are likely to provide economic advantage in Qinchuan cattle. Variations in the FASN genes and their corresponding genotypes may be considered as molecular markers for economic traits in cattle breeding. Copyright © 2017 Elsevier B.V. All rights reserved.

Eye-tracking for clinical decision support: A method to capture automatically what physicians are viewing in the EMR.

PubMed

King, Andrew J; Hochheiser, Harry; Visweswaran, Shyam; Clermont, Gilles; Cooper, Gregory F

2017-01-01

Eye-tracking is a valuable research tool that is used in laboratory and limited field environments. We take steps toward developing methods that enable widespread adoption of eye-tracking and its real-time application in clinical decision support. Eye-tracking will enhance awareness and enable intelligent views, more precise alerts, and other forms of decision support in the Electronic Medical Record (EMR). We evaluated a low-cost eye-tracking device and found the device's accuracy to be non-inferior to a more expensive device. We also developed and evaluated an automatic method for mapping eye-tracking data to interface elements in the EMR (e.g., a displayed laboratory test value). Mapping was 88% accurate across the six participants in our experiment. Finally, we piloted the use of the low-cost device and the automatic mapping method to label training data for a Learning EMR (LEMR) which is a system that highlights the EMR elements a physician is predicted to use.

Photorefraction of eyes: history and future prospects.

PubMed

Howland, Howard C

2009-06-01

A brief history of photorefraction, i.e., the refraction of eyes by photography or computer image capture, is given. The method of photorefraction originated from an optical scheme for secret communication across the Berlin wall. This scheme used a lens whose focus about infinity was modulated by a movable reflecting surface. From this device, it was recognized that the vertebrate eye was such a reflector and that its double-pass pointspread could be used to compute its degree of defocus. Subsequently, a second, totally independent invention, more accurately termed "photoretinoscopy," used an eccentric light source and obtained retinoscopic-like images of the reflex in the pupil of the subject's eyes. Photoretinoscopy has become the preferred method of photorefraction and has been instantiated in a wide variety of devices used in vision screening and research. This has been greatly helped by the parallel development of computer and digital camera technology. It seems likely that photorefractive methods will continue to be refined and may eventually become ubiquitous in clinical practice.

An easy-to-build, low-budget point-of-care ultrasound simulator: from Linux to a web-based solution.

PubMed

Damjanovic, Domagoj; Goebel, Ulrich; Fischer, Benedikt; Huth, Martin; Breger, Hartmut; Buerkle, Hartmut; Schmutz, Axel

2017-12-01

Hands-on training in point-of-care ultrasound (POC-US) should ideally comprise bedside teaching, as well as simulated clinical scenarios. High-fidelity phantoms and portable ultrasound simulation systems are commercially available, however, at considerable costs. This limits their suitability for medical schools. A Linux-based software for Emergency Department Ultrasound Simulation (edus2TM) was developed by Kulyk and Olszynski in 2011. Its feasibility for POC-US education has been well-documented, and shows good acceptance. An important limitation to an even more widespread use of edus2, however, may be due to the need for a virtual machine for WINDOWS ® systems. Our aim was to adapt the original software toward an HTML-based solution, thus making it affordable and applicable in any simulation setting. We created an HTML browser-based ultrasound simulation application, which reads the input of different sensors, triggering an ultrasound video to be displayed on a respective device. RFID tags, NFC tags, and QR Codes™ have been integrated into training phantoms or were attached to standardized patients. The RFID antenna was hidden in a mock ultrasound probe. The application is independent from the respective device. Our application was used successfully with different trigger/scanner combinations and mounted readily into simulated training scenarios. The application runs independently from operating systems or electronic devices. This low-cost, browser-based ultrasound simulator is easy-to-build, very adaptive, and independent from operating systems. It has the potential to facilitate POC-US training throughout the world, especially in resource-limited areas.

Multicarrier airborne ultrasound transmission with piezoelectric transducers.

PubMed

Ens, Alexander; Reindl, Leonhard M

2015-05-01

In decentralized localization systems, the received signal has to be assigned to the sender. Therefore, longrange airborne ultrasound communication enables the transmission of an identifier of the sender within the ultrasound signal to the receiver. Further, in areas with high electromagnetic noise or electromagnetic free areas, ultrasound communication is an alternative. Using code division multiple access (CDMA) to transmit data is ineffective in rooms due to high echo amplitudes. Further, piezoelectric transducers generate a narrow-band ultrasound signal, which limits the data rate. This work shows the use of multiple carrier frequencies in orthogonal frequency division multiplex (OFDM) and differential quadrature phase shift keying modulation with narrowband piezoelectric devices to achieve a packet length of 2.1 ms. Moreover, the adapted channel coding increases data rate by correcting transmission errors. As a result, a 2-carrier ultrasound transmission system on an embedded system achieves a data rate of approximately 5.7 kBaud. Within the presented work, a transmission range up to 18 m with a packet error rate (PER) of 13% at 10-V supply voltage is reported. In addition, the transmission works up to 22 m with a PER of 85%. Moreover, this paper shows the accuracy of the frame synchronization over the distance. Consequently, the system achieves a standard deviation of 14 μs for ranges up to 10 m.

[INVITED] Surface plasmon cavities on optical fiber end-facets for biomolecule and ultrasound detection

NASA Astrophysics Data System (ADS)

Yang, Tian; He, Xiaolong; Zhou, Xin; Lei, Zeyu; Wang, Yalin; Yang, Jie; Cai, De; Chen, Sung-Liang; Wang, Xueding

2018-05-01

Integrating surface plasmon resonance (SPR) devices upon single-mode fiber (SMF) end facets renders label-free sensing systems that have a simple dip-and-read configuration, a small form factor, high compatibility with fiber-optic techniques, and invasive testing capability. Such devices are not only low cost replacement of current equipments in centralized laboratories, but also highly desirable for opening paths to new applications of label-free optical sensing technologies, such as point-of-care immunological tests and intravascular ultrasound imaging. In this paper, we explain the requirements and challenges for such devices from the perspectives of biomolecule and ultrasound detection applications. In such a context, we review our recent work on SMF end-facet SPR cavities. This include a glue-and-strip fabrication method to transfer a nano-patterned thin gold film to the SMF end-facet with high yield, high quality and high alignment precision, the designs of distributed Bragg reflector (DBR) and distributed feedback (DFB) SPR cavities that couple efficiently with the SMF guided mode and reach quality factors of over 100, and the preliminary results for biomolecule interaction sensing and ultrasound detection. The particular advantages and potential values of these devices have been discussed, in terms of sensitivity, data reliability, reproducibility, bandwidth, etc.

Microprocessor controlled compliance monitor for eye drop medication.

PubMed

Hermann, M M; Diestelhorst, M

2006-07-01

The effectiveness of a self administered eye drop medication can only be assessed if the compliance is known. The authors studied the specificity and sensitivity of a new microprocessor controlled monitoring device. The monitoring system was conducted by an 8 bit microcontroller for data acquisition and storage with sensors measuring applied pressure to the bottle, temperature, and vertical position. 10 devices were mounted under commercial 10 ml eye drops. Test subjects had to note down each application manually. A total of 15 applications each within 3 days was intended. Manual reports confirmed 15 applications for each of the 10 bottles. The monitoring devices detected a total of 149 events; one was missed; comprising a sensitivity of 99%. Two devices registered three applications, which did not appear in the manual protocols, indicating a specificity of about 98%. Refrigerated bottles were correctly identified. The battery lifetime exceeded 60 days. The new monitoring device demonstrated a high reliability of the collected compliance data. The important, yet often unknown, influence of compliance in patient care and clinical trials shall be illuminated by the new device. This may lead to a better adapted patient care. Studies will profit from a higher credibility and results will be less influenced by non-compliance.

Real-time evaluation of diffusion of the local anesthetic solution during peribulbar block using ultrasound imaging and clinical correlates of diffusion.

PubMed

Luyet, Cédric; Eng, Kenneth T; Kertes, Peter J; Avila, Arsenio; Muni, Rajeev H; McHardy, Paul

2012-01-01

The aims of this prospective observational study were to assess the incidence of intraconal spread during peribulbar (extraconal) anesthesia by real-time ultrasound imaging of the retro-orbital compartment and to determine whether a complete sensory and motor block (with akinesia) of the eye is directly related to the intraconal spread. Ultrasound imaging was performed in 100 patients who underwent a surgical procedure on the posterior segment of the eye. All patients received a peribulbar block using the inferolateral approach. Once the needle was in place, a linear ultrasound transducer was placed over the eyelid and the spread of local anesthetics was assessed during the injection (real time). Akinesia was assessed by a blinded observer 10 minutes after block placement. The incidence of intraconal spread and its correlation with a complete akinesia was measured. The overall block failure rate was 28% in terms of akinesia, and the rate of rescue blocks was 20%. Clear intraconal spread during injection of the local anesthetic mixture could be detected with ultrasound imaging in 61 of 100 patients. The positive predictive value for successful block when intraconal spread was detected was 98% (95% confidence interval, 91%-100%). The association between clear and no evidence of intraconal spread and effective block was statistically significant (χ test, P < 0.001). Ultrasound imaging provides information of local anesthetic spread within the retro-orbital space, which might assist in the prediction of block success.

Applications of ultrasound in dentistry.

PubMed

Walmsley, A D

1988-01-01

An ultrasonic descaler working at kHz frequencies is used in dentistry to remove attached deposits from the teeth. Such devices offer many advantages over conventional hand instruments by reducing both the work and time involved in the clinical descaling process. Although it is a recognised clinical instrument, there has been little attempt to standardise its acoustic power output. A parameter which may characterise adequately the acoustic emission from these instruments is the displacement amplitude of the probe tip. Modification of the ultrasonic descaler generator has led to the further use of the instrument in other dental areas. Diagnostic applications of MHz ultrasound is limited by the structure and arrangement of the dental tissues. Therapeutic ultrasound has been used to treat a variety of dentally related ailments, and ultrasonic cleaning baths are used to clean both dental instruments and materials.

Endocavity Ultrasound Probe Manipulators

PubMed Central

Stoianovici, Dan; Kim, Chunwoo; Schäfer, Felix; Huang, Chien-Ming; Zuo, Yihe; Petrisor, Doru; Han, Misop

2014-01-01

We developed two similar structure manipulators for medical endocavity ultrasound probes with 3 and 4 degrees of freedom (DoF). These robots allow scanning with ultrasound for 3-D imaging and enable robot-assisted image-guided procedures. Both robots use remote center of motion kinematics, characteristic of medical robots. The 4-DoF robot provides unrestricted manipulation of the endocavity probe. With the 3-DoF robot the insertion motion of the probe must be adjusted manually, but the device is simpler and may also be used to manipulate external-body probes. The robots enabled a novel surgical approach of using intraoperative image-based navigation during robot-assisted laparoscopic prostatectomy (RALP), performed with concurrent use of two robotic systems (Tandem, T-RALP). Thus far, a clinical trial for evaluation of safety and feasibility has been performed successfully on 46 patients. This paper describes the architecture and design of the robots, the two prototypes, control features related to safety, preclinical experiments, and the T-RALP procedure. PMID:24795525

Comparison between high-intensity focused ultrasound devices for the treatment of patients with localized prostate cancer

NASA Astrophysics Data System (ADS)

Kim, Hakushi; Tomonaga, Tetsuro; Shoji, Sunao; Uchida, Toyoaki

2017-03-01

To evaluate the association between long-term clinical outcomes and morbidity of patients with prostate cancer who underwent high-intensity focused ultrasound (HIFU). We included 918 patients with stage T1c-T3N0M0 prostate cancer who were treated with Sonablate™ (SB) devices during 1999-2012 and followed-up for >2 years. Risk stratification and complication rates were compared between the treatment groups. The 10-year overall and cancer-specific survival rates were 89.6% and 97.4%, respectively. The 5-year biochemical disease-free survival (bDFS) rates in the SB200/500, SB500 version 4, and SB500 tissue change monitor groups were 48.3%, 62.3%, and 82.0%, respectively (p < 0.0001). In the low-, intermediate-, and high-risk categories, the 10-year bDFS rates for all patients were 63%, 52%, and 32%, respectively (p < 0.0001), whereas the 5-year bDFS rates in the tissue change monitor group were 95%, 84%, and 72%, respectively (p = 0.0134). The overall negative biopsy rate was 87.3%. Multivariate analysis showed pre-treatment serum prostate-specific antigen levels, neoadjuvant hormonal therapy, and devices as significant predictors (p < 0.0001). Urethral stricture, epididymitis, and urinary incontinence were observed in 19.7%, 6.2%, and 2.3% of the cases, respectively. Long-term follow-up with HIFU demonstrated improved clinical outcomes owing to technical, imaging, and technological advancements.

Laser-Induced Focused Ultrasound for Cavitation Treatment: Toward High-Precision Invisible Sonic Scalpel.

PubMed

Lee, Taehwa; Luo, Wei; Li, Qiaochu; Demirci, Hakan; Guo, L Jay

2017-10-01

Beyond the implementation of the photoacoustic effect to photoacoustic imaging and laser ultrasonics, this study demonstrates a novel application of the photoacoustic effect for high-precision cavitation treatment of tissue using laser-induced focused ultrasound. The focused ultrasound is generated by pulsed optical excitation of an efficient photoacoustic film coated on a concave surface, and its amplitude is high enough to produce controllable microcavitation within the focal region (lateral focus <100 µm). Such microcavitation is used to cut or ablate soft tissue in a highly precise manner. This work demonstrates precise cutting of tissue-mimicking gels as well as accurate ablation of gels and animal eye tissues. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrasound

MedlinePlus

Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...

A novel technology using transscleral ultrasound to deliver protein loaded nanoparticles.

PubMed

Huang, Di; Wang, Lili; Dong, Yixuan; Pan, Xin; Li, Ge; Wu, Chuanbin

2014-09-01

This study was designed to investigate the feasibility of silk fibroin nanoparticles (SFNs) for sustained drug delivery in transscleral ultrasound. Fluorescein isothiocynate labeled bovine serum albumin (FITC-BSA, MW 66.45 kDa) was chosen as a model macromolecular protein drug and SFNs were used as nano-carrier systems suitable for ocular drug delivery. Drug loaded nanoparticles (FITC-BSA-SFNs) were first prepared and characterized. In vitro transscleral study under ultrasound exposure (1MHz, 0.5 W/cm(2), 5 min continuous wave) using isolated sclera of rabbit was performed. The posterior eye segment of rabbit was examined for adverse effect by slit-lamp and histology. It was found that FITC-BSA-SFNs possessed sustained release, bioadhesive, and co-permeation characteristics. The ultrasound application significantly improved the penetration efficiency of FITC-BSA-SFNs as compared with passive delivery, meanwhile caused no damages to the ocular tissue and particles themselves. The distribution profile of SFNs revealed rapid and lasting adhesion on the outer scleral tissues, followed by migration into the interior up to one week after treatment. This research suggested a novel non-invasive transscleral administration of macromolecular protein drugs using SFN carriers combining with ultrasound technology. Copyright © 2014 Elsevier B.V. All rights reserved.

Hybrid-modality ocular imaging using a clinical ultrasound system and nanosecond pulsed laser.

PubMed

Lim, Hoong-Ta; Matham, Murukeshan Vadakke

2015-07-01

Hybrid optical modality imaging is a special type of multimodality imaging significantly used in the recent past in order to harness the strengths of different imaging methods as well as to furnish complementary information beyond that provided by any individual method. We present a hybrid-modality imaging system based on a commercial clinical ultrasound imaging (USI) system using a linear array ultrasound transducer (UST) and a tunable nanosecond pulsed laser as the source. The integrated system uses photoacoustic imaging (PAI) and USI for ocular imaging to provide the complementary absorption and structural information of the eye. In this system, B-mode images from PAI and USI are acquired at 10 Hz and about 40 Hz, respectively. A linear array UST makes the system much faster compared to other ocular imaging systems using a single-element UST to form B-mode images. The results show that the proposed instrumentation is able to incorporate PAI and USI in a single setup. The feasibility and efficiency of this developed probe system was illustrated by using enucleated pig eyes as test samples. It was demonstrated that PAI could successfully capture photoacoustic signals from the iris, anterior lens surface, and posterior pole, while USI could accomplish the mapping of the eye to reveal the structures like the cornea, anterior chamber, lens, iris, and posterior pole. This system and the proposed methodology are expected to enable ocular disease diagnostic applications and can be used as a preclinical imaging system.

Improved cardiovascular diagnostic accuracy by pocket size imaging device in non-cardiologic outpatients: the NaUSiCa (Naples Ultrasound Stethoscope in Cardiology) study

PubMed Central

2010-01-01

Miniaturization has evolved in the creation of a pocket-size imaging device which can be utilized as an ultrasound stethoscope. This study assessed the additional diagnostic power of pocket size device by both experts operators and trainees in comparison with physical examination and its appropriateness of use in comparison with standard echo machine in a non-cardiologic population. Three hundred four consecutive non cardiologic outpatients underwent a sequential assessment including physical examination, pocket size imaging device and standard Doppler-echo exam. Pocket size device was used by both expert operators and trainees (who received specific training before the beginning of the study). All the operators were requested to give only visual, qualitative insights on specific issues. All standard Doppler-echo exams were performed by expert operators. One hundred two pocket size device exams were performed by experts and two hundred two by trainees. The time duration of the pocket size device exam was 304 ± 117 sec. Diagnosis of cardiac abnormalities was made in 38.2% of cases by physical examination and in 69.7% of cases by physical examination + pocket size device (additional diagnostic power = 31.5%, p < 0.0001). The overall K between pocket size device and standard Doppler-echo was 0.67 in the pooled population (0.84 by experts and 0.58 by trainees). K was suboptimal for trainees in the eyeball evaluation of ejection fraction, left atrial dilation and right ventricular dilation. Overall sensitivity was 91% and specificity 76%. Sensitivity and specificity were lower in trainees than in experts. In conclusion, pocket size device showed a relevant additional diagnostic value in comparison with physical examination. Sensitivity and specificity were good in experts and suboptimal in trainees. Specificity was particularly influenced by the level of experience. Training programs are needed for pocket size device users. PMID:21110840

The Eyes Have It

NASA Technical Reports Server (NTRS)

1999-01-01

NASA'S Ames Research Center contracted with SRI international to contract a device that would be able to anticipate, track, and monitor involuntary ocular movement horizontally, vertically, and with respect to depth-of-field. This development helped research institutions to understand the eye. The Eyetracker, manufactured and distributed by Forward Optical Technologies, Inc. is now used in the clinical/medical field.

Initial results of the FUSION-X-US prototype combining 3D automated breast ultrasound and digital breast tomosynthesis.

PubMed

Schaefgen, Benedikt; Heil, Joerg; Barr, Richard G; Radicke, Marcus; Harcos, Aba; Gomez, Christina; Stieber, Anne; Hennigs, André; von Au, Alexandra; Spratte, Julia; Rauch, Geraldine; Rom, Joachim; Schütz, Florian; Sohn, Christof; Golatta, Michael

2018-06-01

To determine the feasibility of a prototype device combining 3D-automated breast ultrasound (ABVS) and digital breast tomosynthesis in a single device to detect and characterize breast lesions. In this prospective feasibility study, the FUSION-X-US prototype was used to perform digital breast tomosynthesis and ABVS in 23 patients with an indication for tomosynthesis based on current guidelines after clinical examination and standard imaging. The ABVS and tomosynthesis images of the prototype were interpreted separately by two blinded experts. The study compares the detection and BI-RADS® scores of breast lesions using only the tomosynthesis and ABVS data from the FUSION-X-US prototype to the results of the complete diagnostic workup. Image acquisition and processing by the prototype was fast and accurate, with some limitations in ultrasound coverage and image quality. In the diagnostic workup, 29 solid lesions (23 benign, including three cases with microcalcifications, and six malignant lesions) were identified. Using the prototype, all malignant lesions were detected and classified as malignant or suspicious by both investigators. Solid breast lesions can be localized accurately and fast by the Fusion-X-US system. Technical improvements of the ultrasound image quality and ultrasound coverage are needed to further study this new device. The prototype combines tomosynthesis and automated 3D-ultrasound (ABVS) in one device. It allows accurate detection of malignant lesions, directly correlating tomosynthesis and ABVS data. The diagnostic evaluation of the prototype-acquired data was interpreter-independent. The prototype provides a time-efficient and technically reliable diagnostic procedure. The combination of tomosynthesis and ABVS is a promising diagnostic approach.

Ultrasound-guided central venous access using Google Glass.

PubMed

Wu, Teresa S; Dameff, Christian J; Tully, Jeffrey L

2014-12-01

The use of ultrasound during invasive bedside procedures is quickly becoming the standard of care. Ultrasound machine placement during procedures often requires the practitioner to turn their head during the procedure to view the screen. Such turning has been implicated in unintentional hand movements in novices. Google Glass is a head-mounted computer with a specialized screen capable of projecting images and video into the view of the wearer. Such technology may help decrease unintentional hand movements. Our aim was to evaluate whether or not medical practitioners at various levels of training could use Google Glass to perform an ultrasound-guided procedure, and to explore potential advantages of this technology. Forty participants of varying training levels were randomized into two groups. One group used Google Glass to perform an ultrasound-guided central line. The other group used traditional ultrasound during the procedure. Video recordings of eye and hand movements were analyzed. All participants from both groups were able to complete the procedure without difficulty. Google Glass wearers took longer to perform the procedure at all training levels (medical student year 1 [MS1]: 193 s vs. 77 s, p > 0.5; MS4: 197s vs. 91s, p ≤ 0.05; postgraduate year 1 [PGY1]: 288s vs. 125 s, p > 0.5; PGY3: 151 s vs. 52 s, p ≤ 0.05), and required more needle redirections (MS1: 4.4 vs. 2.0, p > 0.5; MS4: 4.8 vs. 2.8, p > 0.5; PGY1: 4.4 vs. 2.8, p > 0.5; PGY3: 2.0 vs. 1.0, p > 0.5). In this study, it was possible to perform ultrasound-guided procedures with Google Glass. Google Glass wearers, on average, took longer to gain access, and had more needle redirections, but less head movements were noted. Copyright © 2014 Elsevier Inc. All rights reserved.

Ultrasound

MedlinePlus Videos and Cool Tools

Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two- ... sound waves and appear dark or black. An ultrasound can supply vital information about a mother's pregnancy ...

Traffic control device conspicuity, TechBrief

DOT National Transportation Integrated Search

2013-09-01

The conspicuity of a traffic control device (TCD) is defined as the probability that the device will be noticed. However, there is no agreed-upon measure of what constitutes being noticed. Various measures such as eye fixations, recall, and other ver...

Pragmatic Approach to Device-Independent Color

NASA Technical Reports Server (NTRS)

Brandt, R. D.; Capraro, K. S.

1995-01-01

JPL has been producing images of planetary bodies for over 30 years. The results of an effort to implement device-independent color on three types of devices are described. The goal is to produce near the same eye-brain response when the observer views the image produced by each device under the correct lighting conditions. The procedure used to calibrate and obtain each device profile is described.

Verification and compensation of respiratory motion using an ultrasound imaging system.

PubMed

Chuang, Ho-Chiao; Hsu, Hsiao-Yu; Chiu, Wei-Hung; Tien, Der-Chi; Wu, Ren-Hong; Hsu, Chung-Hsien

2015-03-01

The purpose of this study was to determine if it is feasible to use ultrasound imaging as an aid for moving the treatment couch during diagnosis and treatment procedures associated with radiation therapy, in order to offset organ displacement caused by respiratory motion. A noninvasive ultrasound system was used to replace the C-arm device during diagnosis and treatment with the aims of reducing the x-ray radiation dose on the human body while simultaneously being able to monitor organ displacements. This study used a proposed respiratory compensating system combined with an ultrasound imaging system to monitor the compensation effect of respiratory motion. The accuracy of the compensation effect was verified by fluoroscopy, which means that fluoroscopy could be replaced so as to reduce unnecessary radiation dose on patients. A respiratory simulation system was used to simulate the respiratory motion of the human abdomen and a strain gauge (respiratory signal acquisition device) was used to capture the simulated respiratory signals. The target displacements could be detected by an ultrasound probe and used as a reference for adjusting the gain value of the respiratory signal used by the respiratory compensating system. This ensured that the amplitude of the respiratory compensation signal was a faithful representation of the target displacement. The results show that performing respiratory compensation with the assistance of the ultrasound images reduced the compensation error of the respiratory compensating system to 0.81-2.92 mm, both for sine-wave input signals with amplitudes of 5, 10, and 15 mm, and human respiratory signals; this represented compensation of the respiratory motion by up to 92.48%. In addition, the respiratory signals of 10 patients were captured in clinical trials, while their diaphragm displacements were observed simultaneously using ultrasound. Using the respiratory compensating system to offset, the diaphragm displacement resulted in

Verification and compensation of respiratory motion using an ultrasound imaging system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Ho-Chiao, E-mail: hchuang@mail.ntut.edu.tw; Hsu, Hsiao-Yu; Chiu, Wei-Hung

Purpose: The purpose of this study was to determine if it is feasible to use ultrasound imaging as an aid for moving the treatment couch during diagnosis and treatment procedures associated with radiation therapy, in order to offset organ displacement caused by respiratory motion. A noninvasive ultrasound system was used to replace the C-arm device during diagnosis and treatment with the aims of reducing the x-ray radiation dose on the human body while simultaneously being able to monitor organ displacements. Methods: This study used a proposed respiratory compensating system combined with an ultrasound imaging system to monitor the compensation effectmore » of respiratory motion. The accuracy of the compensation effect was verified by fluoroscopy, which means that fluoroscopy could be replaced so as to reduce unnecessary radiation dose on patients. A respiratory simulation system was used to simulate the respiratory motion of the human abdomen and a strain gauge (respiratory signal acquisition device) was used to capture the simulated respiratory signals. The target displacements could be detected by an ultrasound probe and used as a reference for adjusting the gain value of the respiratory signal used by the respiratory compensating system. This ensured that the amplitude of the respiratory compensation signal was a faithful representation of the target displacement. Results: The results show that performing respiratory compensation with the assistance of the ultrasound images reduced the compensation error of the respiratory compensating system to 0.81–2.92 mm, both for sine-wave input signals with amplitudes of 5, 10, and 15 mm, and human respiratory signals; this represented compensation of the respiratory motion by up to 92.48%. In addition, the respiratory signals of 10 patients were captured in clinical trials, while their diaphragm displacements were observed simultaneously using ultrasound. Using the respiratory compensating system to offset, the

Enhanced ultrasound for advanced diagnostics, ultrasound tomography for volume limb imaging and prosthetic fitting

NASA Astrophysics Data System (ADS)

Anthony, Brian W.

2016-04-01

Ultrasound imaging methods hold the potential to deliver low-cost, high-resolution, operator-independent and nonionizing imaging systems - such systems couple appropriate algorithms with imaging devices and techniques. The increasing demands on general practitioners motivate us to develop more usable and productive diagnostic imaging equipment. Ultrasound, specifically freehand ultrasound, is a low cost and safe medical imaging technique. It doesn't expose a patient to ionizing radiation. Its safety and versatility make it very well suited for the increasing demands on general practitioners, or for providing improved medical care in rural regions or the developing world. However it typically suffers from sonographer variability; we will discuss techniques to address user variability. We also discuss our work to combine cylindrical scanning systems with state of the art inversion algorithms to deliver ultrasound systems for imaging and quantifying limbs in 3-D in vivo. Such systems have the potential to track the progression of limb health at a low cost and without radiation exposure, as well as, improve prosthetic socket fitting. Current methods of prosthetic socket fabrication remain subjective and ineffective at creating an interface to the human body that is both comfortable and functional. Though there has been recent success using methods like magnetic resonance imaging and biomechanical modeling, a low-cost, streamlined, and quantitative process for prosthetic cup design and fabrication has not been fully demonstrated. Medical ultrasonography may inform the design process of prosthetic sockets in a more objective manner. This keynote talk presents the results of progress in this area.

SU-F-T-51: Investigating the Effect of Eye Size and Eccentricity On Normal Tissue Doses From Eye Plaque Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polsdofer, E; Crilly, R

Purpose: This study investigates the effect of eye size and eccentricity on doses to critical tissues by simulating doses in the Plaque Simulator (v. 6.3.1) software. Present OHSU plaque brachytherapy treatment focuses on delivering radiation to the tumor measured with ocular ultrasound plus a small margin and assumes the orbit has the dimensions of a “standard eye.” Accurately modeling the dimensions of the orbit requires a high resolution ocular CT. This study quantifies how standard differences in equatorial diameters and eccentricity affect calculated doses to critical structures in order to query the justification of the additional CT scan to themore » treatment planning process. Methods: Tumors of 10 mm × 10 mm × 5 mm were modeled at the 12:00:00 hour with a latitude of 45 degrees. Right eyes were modeled at a number of equatorial diameters from 17.5 to 28 mm for each of the standard non-notched COMS plaques with silastic inserts. The COMS plaques were fully loaded with uniform activity, centered on the tumor, and prescribed to a common tumor dose (85 Gy/100 hours). Variations in the calculated doses to normal structures were examined to see if the changes were significant. Results: The calculated dose to normal structures show a marked dependence on eye geometry. This is exemplified by fovea dose which more than doubled in the smaller eyes and nearly halved in the larger model. Additional significant dependence was found in plaque size on the calculated dose in spite of all plaques giving the same dose to the prescription point. Conclusion: The variation in dose with eye dimension fully justifies the addition of a high resolution ocular CT to the planning technique. Additional attention must be made to plaque size beyond simply covering the tumor when considering normal tissue dose.« less

Micro-optical artificial compound eyes.

PubMed

Duparré, J W; Wippermann, F C

2006-03-01

Natural compound eyes combine small eye volumes with a large field of view at the cost of comparatively low spatial resolution. For small invertebrates such as flies or moths, compound eyes are the perfectly adapted solution to obtaining sufficient visual information about their environment without overloading their brains with the necessary image processing. However, to date little effort has been made to adopt this principle in optics. Classical imaging always had its archetype in natural single aperture eyes which, for example, human vision is based on. But a high-resolution image is not always required. Often the focus is on very compact, robust and cheap vision systems. The main question is consequently: what is the better approach for extremely miniaturized imaging systems-just scaling of classical lens designs or being inspired by alternative imaging principles evolved by nature in the case of small insects? In this paper, it is shown that such optical systems can be achieved using state-of-the-art micro-optics technology. This enables the generation of highly precise and uniform microlens arrays and their accurate alignment to the subsequent optics-, spacing- and optoelectronics structures. The results are thin, simple and monolithic imaging devices with a high accuracy of photolithography. Two different artificial compound eye concepts for compact vision systems have been investigated in detail: the artificial apposition compound eye and the cluster eye. Novel optical design methods and characterization tools were developed to allow the layout and experimental testing of the planar micro-optical imaging systems, which were fabricated for the first time by micro-optics technology. The artificial apposition compound eye can be considered as a simple imaging optical sensor while the cluster eye is capable of becoming a valid alternative to classical bulk objectives but is much more complex than the first system.

Acoustically active lipospheres containing paclitaxel: a new therapeutic ultrasound contrast agent.

PubMed

Unger, E C; McCreery, T P; Sweitzer, R H; Caldwell, V E; Wu, Y

1998-12-01

Paclitaxel-carrying lipospheres (MRX-552) were developed and evaluated as a new ultrasound contrast agent for chemotherapeutic drug delivery. Paclitaxel was suspended in soybean oil and added to an aqueous suspension of phospholipids in vials. The headspace of the vials was replaced with perfluorobutane gas; the vials were sealed, and they were agitated at 4200 rpm on a shaking device. The resulting lipospheres containing paclitaxel were studied for concentration, size, acute toxicity in mice, and acoustic activity and drug release with ultrasound. Lipospheres containing sudan black dye were produced to demonstrate the acoustically active liposphere (AAL)-ultrasound release concept. Acoustically active lipospheres containing paclitaxel had a mean particle count of approximately 1 x 10(9) particles per mL and a mean size of 2.9 microns. Acute toxicity studies in mice showed a 10-fold reduction in toxicity for paclitaxel in AALs compared with free paclitaxel. The AALs reflected ultrasound as a contrast agent. Increasing amounts of ultrasound energy selectively ruptured the AALs and released the paclitaxel. Acoustically active lipospheres represent a new class of acoustically active drug delivery vehicles. Future studies will assess efficacy of AALs for ultrasound-mediated drug delivery.

Comparison of graft survival following penetrating keratoplasty and Descemet's stripping endothelial keratoplasty in eyes with a glaucoma drainage device.

PubMed

Iverson, Shawn M; Spierer, Oriel; Papachristou, George C; Feuer, William J; Shi, Wei; Greenfield, David S; O'Brien, Terrence P

2018-02-01

To compare corneal graft survival rates after penetrating keratoplasty (PK) and Descemet's stripping endothelial keratoplasty (DSEK) in patients with a glaucoma drainage device (GDD) or medically managed glaucoma. A retrospective chart review was conducted on consecutive patients who underwent primary PK or primary DSEK. Inclusion criteria consisted of eyes with a diagnosis of glaucoma prior to corneal transplantation and a minimum of 6 months of follow-up. Graft failure was defined as an edematous cornea with failure to maintain deturgescence lasting beyond a period of 1 month of intense steroid therapy or vascularization and scarring resulting in irreversible loss of central graft clarity. Corneal graft survival was calculated using Kaplan-Meier survival analysis. Patients were divided into four groups: GDD-PK, GDD-DSEK, medical-PK and medical-DSEK. Fifty-six eyes of 56 patients were identified as meeting inclusion criteria. Among eyes with a GDD, there was no difference in the proportion of failures between PK grafts (48%) and DSEK grafts (50%) (p = 0.90). Failure occurred earlier in DSEK recipients compared to PK recipients, 5.82 ± 6.77 months versus 14.40 ± 7.70 months, respectively (p = 0.04). A Kaplan-Meier analysis did not identify a difference between the four groups with respect to graft failure (p = 0.52). There is no significant difference in graft survival rates between medically and surgically treated glaucoma patients for either PK or DSEK grafts. In patients with GDD, graft failure occurs earlier in DSEK compared to PK.

Comparability of anterior chamber depth measurements with partial coherence interferometry and optical low-coherence reflectometry in pseudophakic eyes.

PubMed

Luft, Nikolaus; Hirnschall, Nino; Farrokhi, Sanaz; Findl, Oliver

2015-08-01

To assess whether anterior chamber depth (ACD) measurements in pseudophakic eyes obtained with partial coherence interferometry (PCI) and optical low-coherence reflectometry (OLCR) devices can be used interchangeably. Vienna Institute for Research in Ocular Surgery, A Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria. Prospective case series. The ACD measurements in 1 eye of each pseudophakic patient were performed with the PCI-based ACMaster device and the OLCR-based Lenstar LS900 device at least 1 day postoperatively. The study comprised 65 eyes of 65 patients with a mean age of 71.7 years ± 9.0 (SD) (range 39 to 91 years). In 15 eyes, no valid ACD readings could be obtained with the OLCR device. No obvious reason for these measurement failures was identified; however, tear-film alterations shortly after surgery were suspected. No significant difference in the mean ACD in the remaining 50 eyes was found between PCI measurements (5019 ± 660 μm; range 4008 to 6181 μm) and OLCR measurements (5015 ± 663 μm; range 4017 to 6163 μm) (P = .06). Three (6%) of 50 measurements were not within the 95% limits of agreement in the Bland-Altman analysis. Pseudophakic ACD measurements with the PCI and OLCR devices can be used interchangeably. The OLCR device proved to be more user-friendly and faster; however, in a substantial number of eyes, no usable values were obtainable. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Evaluation of the validity and reliability of A-scan ultrasound biometry with a single use disposable cover.

PubMed

Cass, K; Thompson, C M; Tromans, C; Wood, I C J

2002-03-01

The UK Medical Devices Agency has suggested that ophthalmic practitioners should, where practicable and not compromising clinical outcome, restrict corneal contact devices to single patient use to minimise a remote theoretical risk of transmission of new variant Creutzfeldt-Jakob disease (vCJD). This study reports on a modified technique of ultrasound A-scan biometry that complies with the MDA recommendations. The right eyes of 37 consecutive hospital patients had a series of biometry readings taken with a Humphrey 820 A-scan instrument with a plane wave transducer use d conventionally and with the addition of a disposable latex cover. Intrasessional repeatability of axial length measurements was similar for conventional readings--mean difference 0.027 mm, 95% confidence intervals (CI) +/- 0.44 mm and those taken with a disposable cover (0.028 mm, CI +/- 0.38). Intersessional repeatability was equivalent with (0.002 mm, CI +.- 0.51) and without a cover (0.03 mm, CI +/- 0.51). Readings with a cover were not significantly different from those without (paired t test; p >0.05), but tended to be greater (mean difference 0.085 mm, CI +/- 0.60). These findings suggest that corneal contact biometry with a disposable cover is a viable and theoretically safer alternative to the conventional technique.

Microprocessor controlled compliance monitor for eye drop medication

PubMed Central

Hermann, M M; Diestelhorst, M

2006-01-01

Background/aims The effectiveness of a self administered eye drop medication can only be assessed if the compliance is known. The authors studied the specificity and sensitivity of a new microprocessor controlled monitoring device. Methods The monitoring system was conducted by an 8 bit microcontroller for data acquisition and storage with sensors measuring applied pressure to the bottle, temperature, and vertical position. 10 devices were mounted under commercial 10 ml eye drops. Test subjects had to note down each application manually. A total of 15 applications each within 3 days was intended. Results Manual reports confirmed 15 applications for each of the 10 bottles. The monitoring devices detected a total of 149 events; one was missed; comprising a sensitivity of 99%. Two devices registered three applications, which did not appear in the manual protocols, indicating a specificity of about 98%. Refrigerated bottles were correctly identified. The battery lifetime exceeded 60 days. Conclusion The new monitoring device demonstrated a high reliability of the collected compliance data. The important, yet often unknown, influence of compliance in patient care and clinical trials shall be illuminated by the new device. This may lead to a better adapted patient care. Studies will profit from a higher credibility and results will be less influenced by non‐compliance. PMID:16540488

Initial Experience with a Wireless Ultrasound-Guided Vacuum-Assisted Breast Biopsy Device

PubMed Central

Choi, E-Ryung; Han, Boo-Kyung; Ko, Eun Sook; Ko, Eun Young; Choi, Ji Soo; Cho, Eun Yoon; Nam, Seok Jin

2015-01-01

Objective To determine the imaging characteristic of frequent target lesions of wireless ultrasound (US)-guided, vacuum-assisted breast biopsy (Wi-UVAB) and to evaluate diagnostic yield, accuracy and complication of the device in indeterminate breast lesions. Materials and Methods From March 2013 to October 2014, 114 women (age range, 29–76 years; mean age, 50.0 years) underwent Wi-UVAB using a 13-gauge needle (Mammotome Elite®; Devicor Medical Products, Cincinnati, OH, USA). In 103 lesions of 96 women with surgical (n = 81) or follow-up (n = 22) data, complications, biopsy procedure, imaging findings of biopsy targets and histologic results were reviewed. Results Mean number of biopsy cores was 10 (range 4–25). Nine patients developed moderate bleeding. All lesions were suspicious on US, and included non-mass lesions (67.0%) and mass lesions (33.0%). Visible calcifications on US were evident in 57.3% of the target lesions. Most of the lesions (93.2%) were nonpalpable. Sixty-six (64.1%) were malignant [ductal carcinoma in situ (DCIS) rate, 61%] and 12 were high-risk lesions (11.7%). Histologic underestimation was identified in 11 of 40 (27.5%). DCIS cases and in 3 of 9 (33.3%) high-risk lesions necessitating surgery. There was no false-negative case. Conclusion Wi-UVAB is very handy and advantageous for US-unapparent non-mass lesions to diagnose DCIS, especially for calcification cases. Histologic underestimation is unavoidable; still, Wi-UVAB is safe and accurate to diagnose a malignancy. PMID:26630136

Models to teach lung sonopathology and ultrasound-guided thoracentesis.

PubMed

Wojtczak, Jacek A

2014-12-01

Lung sonography allows rapid diagnosis of lung emergencies such as pulmonary edema, hemothorax or pneumothorax. The ability to timely diagnose an intraoperative pneumothorax is an important skill for the anesthesiologist. However, lung ultrasound exams require an interpretation of not only real images but also complex acoustic artifacts such as A-lines and B-lines. Therefore, appropriate training to gain proficiency is important. Simulated environment using ultrasound phantom models allows controlled, supervised learning. We have developed hybrid models that combine dry or wet polyurethane foams, porcine rib cages and human hand simulating a rib cage. These models simulate fairly accurately pulmonary sonopathology and allow supervised teaching of lung sonography with the immediate feedback. In-vitro models can also facilitate learning of procedural skills, improving transducer and needle positioning and movement, rapid recognition of thoracic anatomy and hand - eye coordination skills. We described a new model to teach an ultrasound guided thoracentesis. This model consists of the experimenter's hand placed on top of the water-filled container with a wet foam. Metacarpal bones of the human hand simulate a rib cage and a wet foam simulates a diseased lung immersed in the pleural fluid. Positive fluid flow offers users feedback when a simulated pleural effusion is accurately assessed.

Diurnal variation of eye movement and heart rate variability in the human fetus at term.

PubMed

Morokuma, S; Horimoto, N; Satoh, S; Nakano, H

2001-07-01

To elucidate diurnal variations in eye movement and fetal heart rate (FHR) variability in the term fetus, we observed these two parameters continuously for 24 h, using real-time ultrasound and Doppler cardiotocograph, respectively. Studied were five uncomplicated fetuses at term. The time series data of the presence and absence of eye movement and mean FHR value for each 1 min were analyzed using the maximum entropy method (MEM) and subsequent nonlinear least squares fitting. According to the power value of eye movement, all five cases were classified into two groups: three cases in the large power group and two cases in the small power group. The acrophases of eye movement and FHR variability in the large power group were close, thereby implying the existence of a diurnal rhythm in both these parameters and also that they are synchronized. In the small power group, the acrophases were separated. The synchronization of eye movement and FHR variability in the large power group suggests that these phenomena are governed by a common central mechanism related to diurnal rhythm generation.

Evaluation of ultrasound techniques for brain injury detection

NASA Astrophysics Data System (ADS)

Mobley, Joel; Kasili, Paul M.; Norton, Stephen J.; Vo-Dinh, Tuan

1998-05-01

In this work, we examine the physics underlying wave propagation in the head to evaluate various ultrasonic transducers for use in a brian injury detection device. The results of measurements of the attenuation coefficient and phase velocity for ultrasonic propagation in samples of brain tissue and skull bone from sheep are presented. The material properties are then used to investigate the propagation of ultrasonic pressure fields in the head. The ultrasound fields for three different transducers are calculated for propagation in a simulated brain/skull model. The model is constructed using speed-of-sound and mass density values of the two tissue types. The impact of the attenuation on the ultrasound fields is then examined. Finally, the relevant points drawn from these discussions are summarized. We hope to minimize the confounding effects of the skull by using sub-MHz ultrasound while maintaining the necessary temporal and spatial resolution to successfully detect injury in the brain.

Learning Ultrasound-Guided Needle Insertion Skills through an Edutainment Game

NASA Astrophysics Data System (ADS)

Chan, Wing-Yin; Ni, Dong; Pang, Wai-Man; Qin, Jing; Chui, Yim-Pan; Yu, Simon Chun-Ho; Heng, Pheng-Ann

Ultrasound-guided needle insertion is essential in many of minimally invasive surgeries or procedures, such as biopsy, drug delivery, spinal anaesthesia, etc. Accurate and safe needle insertion is a difficult task due to the high requirement of hand-eye coordination skills. Many proposed virtual reality (VR) based training systems put their emphasis on realistic simulation instead of pedagogical efficiency. The lack of schematic training scenario leads to boredom of repetitive operations. To solve this, we present our novel training system with the integration of game elements in order to retain the trainees' enthusiasm. Task-oriented scenarios, time attack scenarios and performance evaluation are introduced. Besides, some state-of-art technologies are also presented, including ultrasound simulation, needle haptic rendering as well as a mass-spring-based needle-tissue interaction simulation. These works are shown to be effective to keep the trainees up with learning.

Abdominal aortic aneurysm screening program using hand-held ultrasound in primary healthcare

PubMed Central

Kostov, Belchin; Navarro González, Marta; Cararach Salami, Daniel; Pérez Jiménez, Alfonso; Gilabert Solé, Rosa; Bru Saumell, Concepció; Donoso Bach, Lluís; Villalta Martí, Mireia; González-de Paz, Luis; Ruiz Riera, Rafael; Riambau Alonso, Vicenç; Acar-Denizli, Nihan; Farré Almacellas, Marta; Ramos-Casals, Manuel; Benavent Àreu, Jaume

2017-01-01

We determined the feasibility of abdominal aortic aneurysm (AAA) screening program led by family physicians in public primary healthcare setting using hand-held ultrasound device. The potential study population was 11,214 men aged ≥ 60 years attended by three urban, public primary healthcare centers. Participants were recruited by randomly-selected telephone calls. Ultrasound examinations were performed by four trained family physicians with a hand-held ultrasound device (Vscan®). AAA observed were verified by confirmatory imaging using standard ultrasound or computed tomography. Cardiovascular risk factors were determined. The prevalence of AAA was computed as the sum of previously-known aneurysms, aneurysms detected by the screening program and model-based estimated undiagnosed aneurysms. We screened 1,010 men, with mean age of 71.3 (SD 6.9) years; 995 (98.5%) men had normal aortas and 15 (1.5%) had AAA on Vscan®. Eleven out of 14 AAA-cases (78.6%) had AAA on confirmatory imaging (one patient died). The total prevalence of AAA was 2.49% (95%CI 2.20 to 2.78). The median aortic diameter at diagnosis was 3.5 cm in screened patients and 4.7 cm (p<0.001) in patients in whom AAA was diagnosed incidentally. Multivariate logistic regression analysis identified coronary heart disease (OR = 4.6, 95%CI 1.3 to 15.9) as the independent factor with the highest odds ratio. A screening program led by trained family physicians using hand-held ultrasound was a feasible, safe and reliable tool for the early detection of AAA. PMID:28453577

Aesthetic ultrasound therapy

NASA Astrophysics Data System (ADS)

Barthe, Peter G.; Slayton, Michael H.

2012-10-01

Ultrasound provides key benefits in aesthetic surgery compared to laser and RF based energy sources. We present results of research, development, pre-clinical and clinical studies, regulatory clearance and commercialization of a revolutionary non-invasive aesthetic ultrasound imaging and therapy system. Clinical applications for this platform include non-invasive face-lifts, brow-lifts, and neck-lifts achieved through fractionated treatment of the superficial musculoaponeurotic system (SMAS) and subcutaneous tissue. Treatment consists of placing a grid of micro-coagulative lesions on the order of 1 mm3 at depths in skin of 1 to 6 mm, source energy levels of 0.1 to 3 J, and spacing on the order of 1.5 mm, from 4 to 10 MHz dual-mode image/treat transducers. System details are described, as well as a regulatory pathway consisting of acoustic and bioheat simulations, source characterization (hydrophone, radiation force, and Schlieren), pre-clinical studies (porcine skin ex vivo, in vivo, and human cadaver), human safety studies (treat and resect) and efficacy trials which culminated in FDA clearance (2009) under a new device classification and world-wide usage. Clinical before and after photographs are presented which validate the clinical approach.

Video-based eye tracking for neuropsychiatric assessment.

PubMed

Adhikari, Sam; Stark, David E

2017-01-01

This paper presents a video-based eye-tracking method, ideally deployed via a mobile device or laptop-based webcam, as a tool for measuring brain function. Eye movements and pupillary motility are tightly regulated by brain circuits, are subtly perturbed by many disease states, and are measurable using video-based methods. Quantitative measurement of eye movement by readily available webcams may enable early detection and diagnosis, as well as remote/serial monitoring, of neurological and neuropsychiatric disorders. We successfully extracted computational and semantic features for 14 testing sessions, comprising 42 individual video blocks and approximately 17,000 image frames generated across several days of testing. Here, we demonstrate the feasibility of collecting video-based eye-tracking data from a standard webcam in order to assess psychomotor function. Furthermore, we were able to demonstrate through systematic analysis of this data set that eye-tracking features (in particular, radial and tangential variance on a circular visual-tracking paradigm) predict performance on well-validated psychomotor tests. © 2017 New York Academy of Sciences.

Pseudo-cat's eye for improved tilt-immune interferometry.

PubMed

Speake, Clive C; Bradshaw, Miranda J

2015-08-20

We present a new simple optical design for a cat's eye retroreflector. We describe the design of the new optical configuration and its use in tilt-immune interferometry where it enables the tracking of the displacement of a plane target mirror with minimum sensitivity to its tilt about axes orthogonal to the interferometer's optical axis. In this application the new cat's eye does not behave as a perfect retroreflector and we refer to it as a "pseudo"-cat's eye (PCE). The device allows, for the first time, tilt-immune interferometric displacement measurements in cases where the nominal distance to the target mirror is significantly larger than the length of the cat's eye. We describe the general optical characteristics of the PCE and compare its performance in our application with that of a conventional cat's eye optical configuration using ABCD matrices and Zemax analyses. We further suggest a simple modification to the design that would enable the PCE to behave as a perfect cat's eye, and this design may provide an advantageous solution for other applications.

Skin temperature increase mediated by wearable, long duration, low-intensity therapeutic ultrasound

NASA Astrophysics Data System (ADS)

Langer, Matthew D.; Huang, Wenyi; Ghanem, Angi; Guo, Yuan; Lewis, George K.

2017-03-01

One of the safety concerns with the delivery of therapeutic ultrasound is overheating of the transducer-skin interface due to poor or improper coupling. The objective of this research was to define a model that could be used to calculate the heating in the skin as a result of a novel, wearable long-duration ultrasound device. This model was used to determine that the maximum heating in the skin remained below the minimum threshold necessary to cause thermal injury over multiple hours of use. In addition to this model data, a human clinical study used wire thermocouples on the skin surface to measure heating characteristics during treatment with the sustained ultrasound system. Parametric analysis of the model determined that the maximum temperature increase is at the surface of the skin ranged from 40-41.8° C when perfusion was taken into account. The clinical data agreed well with the model predictions. The average steady state temperature observed across all 44 subjects was 40°C. The maximum temperature observed was less than 44° C, which is clinically safe for over 5 hours of human skin contact. The resultant clinical temperature data paired well with the model data suggesting the model can be used for future transducer and ultrasound system design simulation. As a result, the device was validated for thermal safety for typical users and use conditions.

Ultrasound therapy applicators for controlled thermal modification of tissue

NASA Astrophysics Data System (ADS)

Burdette, E. Clif; Lichtenstiger, Carol; Rund, Laurie; Keralapura, Mallika; Gossett, Chad; Stahlhut, Randy; Neubauer, Paul; Komadina, Bruce; Williams, Emery; Alix, Chris; Jensen, Tor; Schook, Lawrence; Diederich, Chris J.

2011-03-01

Heat therapy has long been used for treatments in dermatology and sports medicine. The use of laser, RF, microwave, and more recently, ultrasound treatment, for psoriasis, collagen reformation, and skin tightening has gained considerable interest over the past several years. Numerous studies and commercial devices have demonstrated the efficacy of these methods for treatment of skin disorders. Despite these promising results, current systems remain highly dependent on operator skill, and cannot effectively treat effectively because there is little or no control of the size, shape, and depth of the target zone. These limitations make it extremely difficult to obtain consistent treatment results. The purpose of this study was to determine the feasibility for using acoustic energy for controlled dose delivery sufficient to produce collagen modification for the treatment of skin tissue in the dermal and sub-dermal layers. We designed and evaluated a curvilinear focused ultrasound device for treating skin disorders such as psoriasis, stimulation of wound healing, tightening of skin through shrinkage of existing collagen and stimulation of new collagen formation, and skin cancer. Design parameters were examined using acoustic pattern simulations and thermal modeling. Acute studies were performed in 201 freshly-excised samples of young porcine underbelly skin tissue and 56 in-vivo treatment areas in 60- 80 kg pigs. These were treated with ultrasound (9-11MHz) focused in the deep dermis. Dose distribution was analyzed and gross pathology assessed. Tissue shrinkage was measured based on fiducial markers and video image registration and analyzed using NIH Image-J software. Comparisons were made between RF and focused ultrasound for five energy ranges. In each experimental series, therapeutic dose levels (60degC) were attained at 2-5mm depth. Localized collagen changes ranged from 1-3% for RF versus 8-15% for focused ultrasound. Therapeutic ultrasound applied at high

Eye-tracking for clinical decision support: A method to capture automatically what physicians are viewing in the EMR

PubMed Central

King, Andrew J.; Hochheiser, Harry; Visweswaran, Shyam; Clermont, Gilles; Cooper, Gregory F.

2017-01-01

Eye-tracking is a valuable research tool that is used in laboratory and limited field environments. We take steps toward developing methods that enable widespread adoption of eye-tracking and its real-time application in clinical decision support. Eye-tracking will enhance awareness and enable intelligent views, more precise alerts, and other forms of decision support in the Electronic Medical Record (EMR). We evaluated a low-cost eye-tracking device and found the device’s accuracy to be non-inferior to a more expensive device. We also developed and evaluated an automatic method for mapping eye-tracking data to interface elements in the EMR (e.g., a displayed laboratory test value). Mapping was 88% accurate across the six participants in our experiment. Finally, we piloted the use of the low-cost device and the automatic mapping method to label training data for a Learning EMR (LEMR) which is a system that highlights the EMR elements a physician is predicted to use. PMID:28815151

High-speed adaptive optics line scan confocal retinal imaging for human eye.

PubMed

Lu, Jing; Gu, Boyu; Wang, Xiaolin; Zhang, Yuhua

2017-01-01

Continuous and rapid eye movement causes significant intraframe distortion in adaptive optics high resolution retinal imaging. To minimize this artifact, we developed a high speed adaptive optics line scan confocal retinal imaging system. A high speed line camera was employed to acquire retinal image and custom adaptive optics was developed to compensate the wave aberration of the human eye's optics. The spatial resolution and signal to noise ratio were assessed in model eye and in living human eye. The improvement of imaging fidelity was estimated by reduction of intra-frame distortion of retinal images acquired in the living human eyes with frame rates at 30 frames/second (FPS), 100 FPS, and 200 FPS. The device produced retinal image with cellular level resolution at 200 FPS with a digitization of 512×512 pixels/frame in the living human eye. Cone photoreceptors in the central fovea and rod photoreceptors near the fovea were resolved in three human subjects in normal chorioretinal health. Compared with retinal images acquired at 30 FPS, the intra-frame distortion in images taken at 200 FPS was reduced by 50.9% to 79.7%. We demonstrated the feasibility of acquiring high resolution retinal images in the living human eye at a speed that minimizes retinal motion artifact. This device may facilitate research involving subjects with nystagmus or unsteady fixation due to central vision loss.

Eye protection in dental laboratories.

PubMed

Palenik, C J

1997-09-01

Many dental laboratory procedures increase the chances of serious eye injury. This would include traumatic injuries due to projectiles or through exposure to harsh chemicals or heat and infections from contact with patient body fluids. To help assure a safer working environment, awareness of the need for eye protection must be established and maintained by all laboratory personnel. The purpose of this article are: 1) to list the applicable federal regulations concerning eye safety in dental laboratory workplaces; 2) to describe the various types of appropriate eyewear; and 3) to identify which protective devices best prevent exposure to specific types of hazards. The goal of this article is to help dental laboratories with their employee safety programs, especially concerning the selection of protective eyewear. Such programs must include engineering controls and work practice controls plus appropriate personal protective equipment. Laboratories today must comply with safety mandates in the most effective and efficient manner.

Comparison of immersion ultrasound, partial coherence interferometry, and low coherence reflectometry for ocular biometry in cataract patients.

PubMed

Montés-Micó, Robert; Carones, Francesco; Buttacchio, Antonietta; Ferrer-Blasco, Teresa; Madrid-Costa, David

2011-09-01

To compare ocular biometry parameters measured with immersion ultrasound, partial coherence interferometry, and low coherence reflectometry in cataract patients. Measurements of axial length and anterior chamber depth were analyzed and compared using immersion ultrasound, partial coherence interferometry, and low coherence reflectometry. Keratometry (K), flattest axis, and white-to-white measurements were compared between partial coherence interferometry and low coherence reflectometry. Seventy-eight cataract (LOCS II range: 1 to 3) eyes of 45 patients aged between 42 and 90 years were evaluated. A subanalysis as a function of cataract degree was done for axial length and anterior chamber depth between techniques. No statistically significant differences were noted for the study cohort or within each cataract degree among the three techniques for axial length and anterior chamber depth (P>.05, ANOVA test). Measurements between techniques were highly correlated for axial length (R=0.99) and anterior chamber depth (R=0.90 to 0.96) for all methods. Keratometry, flattest axis, and white-to-white measurements were comparable (paired t test, P>.1) and correlated well between partial coherence interferometry and low coherence reflectometry (K1 [R=0.95), K2 [R=0.97], flattest axis [R=0.95], and white-to-white [R=0.92]). Immersion ultrasound, partial coherence interferometry, and low coherence reflectometry provided comparable ocular biometry measurements in cataractous eyes. Copyright 2011, SLACK Incorporated.

Design and characterization of a high-power ultrasound driver with ultralow-output impedance

NASA Astrophysics Data System (ADS)

Lewis, George K.; Olbricht, William L.

2009-11-01

We describe a pocket-sized ultrasound driver with an ultralow-output impedance amplifier circuit (less than 0.05 Ω) that can transfer more than 99% of the voltage from a power supply to the ultrasound transducer with minimal reflections. The device produces high-power acoustical energy waves while operating at lower voltages than conventional ultrasound driving systems because energy losses owing to mismatched impedance are minimized. The peak performance of the driver is measured experimentally with a PZT-4, 1.54 MHz, piezoelectric ceramic, and modeled using an adjusted Mason model over a range of transducer resonant frequencies. The ultrasound driver can deliver a 100 Vpp (peak to peak) square-wave signal across 0-8 MHz ultrasound transducers in 5 ms bursts through continuous wave operation, producing acoustic powers exceeding 130 W. Effects of frequency, output impedance of the driver, and input impedance of the transducer on the maximum acoustic output power of piezoelectric transducers are examined. The small size, high power, and efficiency of the ultrasound driver make this technology useful for research, medical, and industrial ultrasonic applications.

Design and characterization of a high-power ultrasound driver with ultralow-output impedance.

PubMed

Lewis, George K; Olbricht, William L

2009-11-01

We describe a pocket-sized ultrasound driver with an ultralow-output impedance amplifier circuit (less than 0.05 ohms) that can transfer more than 99% of the voltage from a power supply to the ultrasound transducer with minimal reflections. The device produces high-power acoustical energy waves while operating at lower voltages than conventional ultrasound driving systems because energy losses owing to mismatched impedance are minimized. The peak performance of the driver is measured experimentally with a PZT-4, 1.54 MHz, piezoelectric ceramic, and modeled using an adjusted Mason model over a range of transducer resonant frequencies. The ultrasound driver can deliver a 100 V(pp) (peak to peak) square-wave signal across 0-8 MHz ultrasound transducers in 5 ms bursts through continuous wave operation, producing acoustic powers exceeding 130 W. Effects of frequency, output impedance of the driver, and input impedance of the transducer on the maximum acoustic output power of piezoelectric transducers are examined. The small size, high power, and efficiency of the ultrasound driver make this technology useful for research, medical, and industrial ultrasonic applications.

Remote artificial eyes using micro-optical circuit for long-distance 3D imaging perception.

PubMed

Thammawongsa, Nopparat; Yupapin, Preecha P

2016-01-01

A small-scale optical device incorporated with an optical nano-antenna is designed to operate as the remote artificial eye using a tiny conjugate mirror. A basic device known as a conjugate mirror can be formed using the artificial eye device, the partially reflected light intensities from input source are interfered and the 3D whispering gallery modes formed within the ring centers, which can be modulated and propagated to the object. The image pixel is obtained at the center ring and linked with the optic nerve in the remote area via the nano-antenna, which is useful for blind people.

Evaluation and comparison of indentation ultrasound biomicroscopy gonioscopy in relative pupillary block, peripheral anterior synechia, and plateau iris configuration.

PubMed

Matsunaga, Koichi; Ito, Kunio; Esaki, Koji; Sugimoto, Kota; Sano, Toru; Miura, Katsuya; Sasoh, Mikio; Uji, Yukitaka

2004-12-01

To evaluate and compare the findings and changes of the anterior chamber angle configuration with indentation ultrasound biomicroscopy (UBM) gonioscopy in relative pupillary block (RPB), peripheral anterior synechia (PAS), and plateau iris configuration (PIC). This study included 73 eyes of 52 patients with RPB (n = 26), PAS (n = 21), or PIC (n = 26). First, a conventional UBM scan was performed using a normal size standard eye cup before indentation. Then, for indentation UBM gonioscopy, scans were performed using a new eye cup that we designed. For evaluation of the angle, angle opening distance 500 and angle recess area were recorded and evaluated with regard to the effect of expansion on the anterior chamber angle. Indentation UBM gonioscopy showed the characteristic images in each of the eyes. The angle of all examined eyes was significantly widened with indentation (P < 0.01). The angle changes in eyes with RPB were significantly greater than in eyes with PAS or PIC (P < 0.01). Indentation UBM gonioscopy is a very useful method for observing the angle and diagnosis of RPB, PAS, and PIC.

Optical projectors simulate human eyes to establish operator's field of view

NASA Technical Reports Server (NTRS)

Beam, R. A.

1966-01-01

Device projects visual pattern limits of the field of view of an operator as his eyes are directed at a given point on a control panel. The device, which consists of two projectors, provides instant evaluation of visual ability at a point on a panel.

Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell.

PubMed

Choe, Se-Woon; Park, Kitae; Park, Chulwoo; Ryu, Jaemyung; Choi, Hojong

2017-12-01

Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors. We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells. Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%). We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

Histological and Ultrastructural Effects of Ultrasound-induced Cavitation on Human Skin Adipose Tissue.

PubMed

Bani, Daniele; Quattrini Li, Alessandro; Freschi, Giancarlo; Russo, Giulia Lo

2013-09-01

In aesthetic medicine, the most promising techniques for noninvasive body sculpturing purposes are based on ultrasound-induced fat cavitation. Liporeductive ultrasound devices afford clinically relevant subcutaneous fat pad reduction without significant adverse reactions. This study aims at evaluating the histological and ultrastructural changes induced by ultrasound cavitation on the different cell components of human skin. Control and ultrasound-treated ex vivo abdominal full-thickness skin samples and skin biopsies from patients pretreated with or without ultrasound cavitation were studied histologically, morphometrically, and ultrastructurally to evaluate possible changes in adipocyte size and morphology. Adipocyte apoptosis and triglyceride release were also assayed. Clinical evaluation of the effects of 4 weekly ultrasound vs sham treatments was performed by plicometry. Compared with the sham-treated control samples, ultrasound cavitation induced a statistically significant reduction in the size of the adipocytes (P < 0.001), the appearance of micropores and triglyceride leakage and release in the conditioned medium (P < 0.05 at 15 min), or adipose tissue interstitium, without appreciable changes in microvascular, stromal, and epidermal components and in the number of apoptotic adipocytes. Clinically, the ultrasound treatment caused a significant reduction of abdominal fat. This study further strengthens the current notion that noninvasive transcutaneous ultrasound cavitation is a promising and safe technology for localized reduction of fat and provides experimental evidence for its specific mechanism of action on the adipocytes.

Can we trust intraocular pressure measurements in eyes with intracameral air?

PubMed

Jóhannesson, Gauti; Lindén, Christina; Eklund, Anders; Behndig, Anders; Hallberg, Per

2014-10-01

To evaluate the effect of intracameral air on intraocular pressure (IOP) measurements using Goldmann applanation tonometry (GAT) and applanation resonance tonometry (ART) in an in-vitro porcine eye model. IOP was measured on thirteen freshly enucleated eyes at three reference pressures: 20, 30, and 40 mmHg. Six measurements/method were performed in a standardized order with GAT and ART respectively. Air was injected intracamerally in the same manner as during Descemet's stripping endothelial keratoplasty (DSEK) and Descemet's membrane endothelial keratoplasty (DMEK), and the measurements were repeated. Measured IOP increased significantly for both tonometry methods after air injection: 0.7 ± 2.1 mmHg for GAT and 10.6 ± 4.9 mmHg for ART. This difference was significant at each reference pressure for ART but not for GAT. Although slightly affected, this study suggests that we can trust GAT IOP-measurements in eyes with intracameral air, such as after DSEK/DMEK operations. Ultrasound-based methods such as ART should not be used.

Motion Estimation Using the Single-row Superposition-type Planar Compound-like Eye

PubMed Central

Cheng, Chi-Cheng; Lin, Gwo-Long

2007-01-01

How can the compound eye of insects capture the prey so accurately and quickly? This interesting issue is explored from the perspective of computer vision instead of from the viewpoint of biology. The focus is on performance evaluation of noise immunity for motion recovery using the single-row superposition-type planar compound like eye (SPCE). The SPCE owns a special symmetrical framework with tremendous amount of ommatidia inspired by compound eye of insects. The noise simulates possible ambiguity of image patterns caused by either environmental uncertainty or low resolution of CCD devices. Results of extensive simulations indicate that this special visual configuration provides excellent motion estimation performance regardless of the magnitude of the noise. Even when the noise interference is serious, the SPCE is able to dramatically reduce errors of motion recovery of the ego-translation without any type of filters. In other words, symmetrical, regular, and multiple vision sensing devices of the compound-like eye have statistical averaging advantage to suppress possible noises. This discovery lays the basic foundation in terms of engineering approaches for the secret of the compound eye of insects.

An Electro-Optic Spatial Light Modulator for Thermoelastic Generation of Programmably Focused Ultrasound.

DTIC Science & Technology

1984-12-01

The concept proposed is an electro - optic technique that would make it possible to spatially modulate a high power pulsed laser beam to thermoelastically induce focused ultrasound in a test material. Being a purely electro - optic device, the modulator, and therefore the depth at which the acoustic focus occurs, can be programmed electronically at electronic speeds. If successful, it would become possible to scan ultrasound continuously in three dimensions within the component or structure under test. (Author)

An electro-optic spatial light modulator for thermoelastic generation of programmably focused ultrasound

NASA Astrophysics Data System (ADS)

1984-12-01

The concept proposed is an electro-optic technique that would make it possible to spatially modulate a high power pulsed laser beam to thermoelastically induce focused ultrasound in a test material. Being a purely electro-optic device, the modulator, and therefore the depth at which the acoustic focus occurs, can be programmed electronically at electronic speeds. If successful, it would become possible to scan ultrasound continuously in three dimensions within the component or structure under test.

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.

PubMed

Tian, Jiajun; Zhang, Qi; Han, Ming

2013-03-11

Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.

Virtual Ultrasound Guidance for Inexperienced Operators

NASA Technical Reports Server (NTRS)

Caine, Timothy; Martin, David

2012-01-01

Medical ultrasound or echocardiographic studies are highly operator-dependent and generally require lengthy training and internship to perfect. To obtain quality echocardiographic images in remote environments, such as on-orbit, remote guidance of studies has been employed. This technique involves minimal training for the user, coupled with remote guidance from an expert. When real-time communication or expert guidance is not available, a more autonomous system of guiding an inexperienced operator through an ultrasound study is needed. One example would be missions beyond low Earth orbit in which the time delay inherent with communication will make remote guidance impractical. The Virtual Ultrasound Guidance system is a combination of hardware and software. The hardware portion includes, but is not limited to, video glasses that allow hands-free, full-screen viewing. The glasses also allow the operator a substantial field of view below the glasses to view and operate the ultrasound system. The software is a comprehensive video program designed to guide an inexperienced operator through a detailed ultrasound or echocardiographic study without extensive training or guidance from the ground. The program contains a detailed description using video and audio to demonstrate equipment controls, ergonomics of scanning, study protocol, and scanning guidance, including recovery from sub-optimal images. The components used in the initial validation of the system include an Apple iPod Classic third-generation as the video source, and Myvue video glasses. Initially, the program prompts the operator to power-up the ultrasound and position the patient. The operator would put on the video glasses and attach them to the video source. After turning on both devices and the ultrasound system, the audio-video guidance would then instruct on patient positioning and scanning techniques. A detailed scanning protocol follows with descriptions and reference video of each view along with

Looking into the Eye with a Smartphone

NASA Astrophysics Data System (ADS)

Colicchia, Giuseppe; Wiesner, Hartmut

2015-02-01

Thanks to their sensors and the large number of apps available, smartphones can be used as a useful tool to carry out new laboratory experiments in physics.1-3 Such devices, very popular among young people, may be a successful approach to improve students' interest in the subject, particularly in a medical context. In addition to their small camera, smartphones usually have an integrated LED light source that is in line with the visual axis of the camera sensor. Using a smartphone, it is hence possible to take photos or videos of the fundus (retina) inside the eye through the pupil. We will explain the optical principles underlying the methods for observing the fundus of the eye (ophthalmoscopy) and describe how students can perform "fundus" photography on eye models using a smartphone.

20 kHz ultrasound assisted treatment of chronic wounds with concurrent optic monitoring

NASA Astrophysics Data System (ADS)

Bawiec, Christopher R.; Sunny, Youhan; Diaz, David; Nadkarni, Sumati; Weingarten, Michael S.; Neidrauer, Michael; Margolis, David J.; Zubkov, Leonid; Lewin, Peter A.

2015-05-01

This paper describes a novel, wearable, battery powered ultrasound applicator that was evaluated as a therapeutic tool for healing of chronic wounds, such as venous ulcers. The low frequency and low intensity (~100mW/cm2) applicator works by generating ultrasound waves with peak-to-peak pressure amplitudes of 55 kPa at 20 kHz. The device was used in a pilot human study (n=25) concurrently with remote optical (diffuse correlation spectroscopy - DCS) monitoring to assess the healing outcome. More specifically, the ulcers' healing status was determined by measuring tissue oxygenation and blood flow in the capillary network. This procedure facilitated an early prognosis of the treatment outcome and - once verified - may eventually enable customization of wound management. The outcome of the study shows that the healing patients of the ultrasound treated group had a statistically improved (p<0.05) average rate of wound healing (20.6%/week) compared to the control group (5.3%/week). In addition, the calculated blood flow index (BFI) decreased more rapidly in wounds that decreased in size, indicating a correlation between BFI and wound healing prediction. Overall, the results presented support the notion that active low frequency ultrasound treatment of chronic venous ulcers accelerates healing when combined with the current standard clinical care. The ultrasound applicator described here provides a user-friendly, fully wearable system that has the potential for becoming the first device suitable for treatment of chronic wounds in patient's homes, which - in turn - would increase patients' compliance and improve quality of life.

Fast scanning probe for ophthalmic echography using an ultrasound motor.

PubMed