Ultrasonic Imaging Device Research Articles

High-intensity therapeutic ultrasound: metrological requirements versus clinical usage

High-intensity therapeutic ultrasound (HITU) is an appealing non-invasive, non-ionizing therapeutic modality with a wide range of tissue interactions ranging from transient permeabilization of cell membranes to thermal ablation. The ability to guide and monitor the treatment with an associated ultrasonic or magnetic resonance imaging device has resulted in a dramatic rise in the clinical use of therapeutic ultrasound in the past two decades. Nevertheless, the range of clinical applications and the number of patients treated has grown at a much higher pace than the definition of standards. In this paper the metrological requirements of the therapeutic beams are reviewed and are compared with the current clinical use of image-guided HITU mostly based on a practical approach. Liver therapy, a particularly challenging clinical application, is discussed to highlight the differences between some complex clinical situations and the experimental conditions of the metrological characterization of ultrasonic transducers.

NAVIGATION AND IMAGING SYSTEM SYCHRONIZED WITH RESPIRATORY AND/OR CARDIAC ACTIVITY

An imaging and navigation system is disclosed herein. The imaging and navigation system includes a computer and an ultrasonic imaging device disposed at least partially within an ultrasound catheter. The ultrasonic imaging device is connected to the computer and is adapted to obtain a generally real time three-dimensional image. The imaging and navigation system also includes a tracking system connected to the computer. The tracking system is adapted to estimate a position of a medical instrument. The imaging and navigation system also includes a display connected to the computer. The display is adapted to depict the generally real time three-dimensional image from the ultrasonic imaging device and to graphically convey the estimated position of the medical instrument.

The Validity and Reproducibility of Pharynx Movement Evaluation at Deglutition by an Ultrasonic Imaging Device and Heart-Beat Microphone

〔目的〕嚥下動態の視覚的，定量的評価法の開発に向けて新たに考案された超音波画像診断装置による画像と，マイクにより録音された嚥下音の周波数解析との組み合わせによる咽頭運動分析方法の妥当性と再現性を検討すること．〔対象〕健常成人4名とした．〔方法〕嚥下音の周波数解析と計測された咽頭運動時間の再現性を従来法である嚥下造影によるものと比較した．本研究の妥当性を検討するためにVFでも同様の測定を実施し比較検討を行った．〔結果〕超音波画像診断装置と音声マイクを用いた嚥下音の周波数解析は，最も咽頭運動の視覚的判断が優良であるVFを用いた測定値と比較して同程度の再現性が得られた．〔結語〕超音波画像診断装置を用いた評価は，誤嚥状態にある患者の定量的な評価手法として有効な手段であると考えられた．

HAND-HELD ULTRASOUND IMAGING DEVICE HAVING REMOVABLE TRANSDUCER ARRAYS

A hand-held ultrasonic imaging device is provided with a removable transducer array. The imaging device has a housing, a display on the housing, and a transducer assembly including a transducer array detachably coupled to the housing. The imaging device may detect the type of transducer array that is coupled to the housing and select a corresponding functional mode for the transducer array. The transducer array may be coupled at different angles to the housing. The transducer array may be coupled to the housing by a pivotable swivel connector.

Guidance Of Invasive Medical Devices By Three Dimensional Ultrasonic Imaging

A three dimensional ultrasonic diagnostic imaging system is operated to guide or observe the operation of an invasive medical device (30) in three dimensions. An interventional system (20) is used to operate the invasive medical device (30) and produces spatially-based information relating to the activity of the invasive medical device (30). The spatially-based information from the interventional system (20) is merged into the three dimensional ultrasonic image data to produce a live three dimensional image of the invasive medical device (30) or its activity. In one embodiment the locations where the activity of the invasive medical device (30) is performed is recorded and displayed in the three dimensional ultrasonic image. The three dimensional ultrasonic image may be shown as an anatomical volume rendered image or as a wire frame model (130) of the anatomy. In another embodiment an integrated three dimensional ultrasonic imaging and invasive device system is described.

The Effects of Employing Pillows for Postural Changes on Ventilation: An Investigation Using an Ultrasonic Imaging Device

[Purpose] We investigated the effects of compression on the posterior surface of the thorax caused by a pillow used for postural changes on the respiratory function. [Subjects] The subjects were 22 healthy males with no history of ailments of the respiratory and circulatory organs. [Methods] With the subjects placed in the supine position, a half-lateral position with a pillow supporting the posterior surface of the thorax (pillow-supported position (1)), and a half-lateral position with pillows supporting the shoulder girdle and the pelvic band (pillow- supported position (2)), the ventilatory volume per breath (hereinafter TV) and expiratory reserve volume (hereinafter ERV) were measured based on the respiratory function, and at the same time, the distanced moved by the diaphragm was measured using an ultrasonic imaging device. [Results] Significantly lower values for TV were observed in the pillow-supported position (1) in comparison to the other postures. Significantly higher values for ERV were observed in the pillow-supported position (1) in comparison to the other postures. Significantly lower values for the distance moved by the diaphragm were observed in the pillow-supported position (1) in comparison to the other postures. [Conclusion] Ventilation decreased in pillow-supported position (1). We therefore consider that the movement of the diaphragm was reduced due to an expanded state caused by increase in residual air in the lungs.

Ultrasonic imaging device

Ultrasonic imaging device

Hardware-efficient realization of a real-time ultrasonic target detection system using IIR filters

In this study, we address the increased computational demands of a frequency-diverse ultrasonic target detection system by developing a zero-phase IIR (ZP-IIR) filter. Several ZP-IIR filter types including Chebyshev-I, Chebyshev- II, and Butterworth were analyzed for their detection performance. The 4th-order filters with 8-bit quantized coefficients are shown to improve the flaw-to-clutter ratio by approximately 10 dB. Furthermore, the reduced adder graph algorithm is used for a hardware realization of ZP-IIR filters that does not require any dedicated multipliers. A small number of coefficients inherent to IIR filters and their multiplierless implementation provide efficient architecture suitable for compact, real-time ultrasonic imaging devices.

Ultrasonic imaging device and the information processing method thereof

An ultrasonic imaging device, comprising: a receiver, for receiving ultrasonic signals which carry information about human body; a processor, for analyzing and processing the received ultrasonic signals in order to get image and/or sound signals; a controller, for issuing at least one instruction; and a recorder, for recording the image and/or sound signals on recording medium in digital form in accordance with the instruction.

Ultrasonographic device and ultrasonographic method

In an ultrasonic imaging device having an image synthesizing unit, correlation between images to be synthesized is computed for balancing between an improvement in contrast resolution and an improvement in spatial resolution, and an amount of displacement between the images is computed. When the amount of displacement is large, the signals after envelop detection are synthesized. When the amount of displacement is small, RF signals are synthesized. Alternatively, the mixing frequency may be variable according to the amount of displacement, and the balance between an improvement in spatial resolution and that in contract resolution is achieved according to a degree of the positional displacement.

Applications of ultrasonography in the diagnosis of soft tissue swellings of the cervicofacial region

To determine the accuracy, sensitivity, specificity and prediction values of ultrasound as a means of diagnosis of cervico-facial soft tissue swellings. We carried out ultrasonographic evaluation of 76 consecutive cases of cervico-facial soft tissue swellings that presented at the Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, Nigeria from August 2002 to November 2003. The patients' demographics and relevant clinical information were obtained. Ultrasonographic evaluation was done using the B-mode transcutaneous ultrasonic imaging device with a transducer frequency of 5MHz. All the lesions were subjected to histopathological examination. There were 43(56.6%) males and 33(43.4%) females whose ages ranged from 2 weeks to 70 years (mean +/- SD; 22 +/- 19.7 years). Histologically, tumours constituted the highest percentage of swellings (35.5%), followed by cysts (26.3%). Males were more predominant in all classes of swellings except benign tumours. The accuracy of ultrasound in the diagnosis of pleomorphic adenoma was 80% and 100% for both adenocarcinoma and hemangioma. It was also 100% for majority of the cysts and HIV associated salivary gland swellings. The sensitivity of ultrasound in the diagnosis of pleomorphic adenoma was 80% and 100% for adenocarcinoma, hemangioma, all the cysts and HIV associated swellings. Ultrasound was also 100% specific in the diagnosis of monomorphic adenoma and hemangioma. Ultrasound is a useful diagnostic tool for cervicofacial soft tissue swellings. The accuracy of diagnosis is enhanced by the characteristics of the probe and the experience of the sonologist.

Ultrasonic imaging device. System and method of use

An ultrasonic probe comprises an elongate structure having a longitudinal axis; a first array of ultrasonic transducer elements extending along an outer surface of the elongate structure in a direction generally parallel to the longitudinal axis; a second array of ultrasonic transducer elements extending along the outer surface of the elongate structure in a direction generally parallel to the longitudinal axis; and a third array of ultrasonic transducer elements extending about the elongate structure in a direction so that it images a plane perpendicular to that imaged by at least one of the first array and the second array, the third array being disposed in a space between the first array and the second array. An electronics module for use with the probe, and an additional probe, to produce internal images of a patient.

Ultrasonic imaging device

This invention provides an ultrasonic imaging system that implements imaging by distinguishing sharply and definitely the echo components generated by scattering in a microbubble contrast medium, from the tissue harmonic components generated by nonlinear propagation of a transmitted pulse. This ultrasonic imaging system, constructed to transmit/receive ultrasonic pulses to/from a living body and form a contrast image of the inside of the living body by using the contrast-imaging microbubbles, repeats the transmitting/receiving operations four times in all, under the same transmitting/receiving focus conditions at different phase angles [(a)=0°, (b)=120°, (c)=−120°, (d)=180°] of the carrier of a transmitted pulse wave including a common envelope signal, sums up three time-series receive echo signals associated with (a), (b), (c), forms the contrast image, sums up two time-series receive echo signals associated with (a), (d), forms an image of the living body having a nonlinear pulse propagation property, and makes a superimposed display of the two kinds of images.

Supersonic shear imaging

There is a great interest for developing in vivo quantitative imaging of the shear tissue properties. This can be achieved by using an ultrafast ultrasonic imaging device able to follow in real time the propagation of low frequency transient shear wave in the body. We have developed such an ultrafast scanner that can give up to 5.000 images/s. From the spatio-temporal evolution of the elastic field a local inversion algorithm allows to recover the shear modulus and viscosity map without the limitations induced by diffraction. Transient shear sources are induced by ultrasonic radiation pressure generated by the ultrasonic probe array. The most interesting configuration that induces high amplitude shear waves used a sonic shear source that moves at supersonic velocities. In vitro and in vivo results will be presented that demonstrate the great interest of supersonic shear imaging.

Circumferential Adjustment of Ultrasound Probe Position to Determine the Optimal Approach to the Internal Jugular Vein: A Noninvasive Geometric Study in Adults

Circumferential adjustment of the position of a two-dimensional ultrasound (US) probe around the neck has been recommended as a strategy for reducing the potential for unintentional common carotid artery puncture during internal jugular venous (IJV) cannulation. We obtained multiple high-resolution US images bilaterally from the necks of 107 adult subjects and analyzed these to determine the degree to which this strategy permits identification of a pathway from the skin to the IJV that minimizes venoarterial overlap while maximizing venous target (angular) width. The method consistently permitted identification of an approach to the IJV superior to that obtainable with any one of four popular surface anatomy-based ("blind") approaches and was even more powerful if used in concert with a US-guided 1) adjustment of the degree of head rotation, 2) choice between a high and low approach, and 3) choice between the right and left IJV. Use of a high-resolution US imaging device also permitted identification of the precise boundaries of additional cervical anatomic structures (nontarget vessels, lymph nodes, and the thyroid gland) potentially relevant to selection of an optimal approach to the IJV.

System and method for tissue biopsy using ultrasonic imaging

A tissue biopsy device uses ultrasonic imaging to guide the biopsy needle. An ultrasonic imaging device comprises three acoustically coupled chambers with an ultrasound transducer in a first chamber, at least a portion of an ultrasound detector in the second chamber and the portion of patient anatomy to be imaged placed in the third chamber, which is intermediate the first and second chambers. The three chambers are filled with an acoustically transmissive liquid. One or more of the end walls dividing the first and third chambers and second and third chambers may be movable to form compression plates that are used to retain the patient anatomy in a fixed position during the imaging and biopsy process. When a structure, such as a lesion, has been located, the imaging may be used to determine the precise location of the lesion in three dimensions. The ultrasonically transmissive fluid is drained from the central third chamber with ultrasonic coupling occurring through the ultrasonically transmissive compression plates and the imaged patient anatomy. This permits real-time imaging of the patient anatomy during the biopsy process. The three-dimensional coordinates are used to provide a manual guide for insertion of the biopsy needle. Light bars may be projected onto the external anatomy of the patient to indicate the desired point of entry of the biopsy needle. The physician may use the real-time imaging to view both the lesion and the biopsy needle. In an alternative embodiment, a biopsy needle may be automatically positioned at the location of the lesion by a three-dimensional positioning system.

Ultrasonic imaging devices and methods of fabrication

An ultrasound catheter suitable for insertion in the body lumens of a patient during medical procedures is provided. An ultrasound transducer may be provided at the distal tip of the catheter. An inflatable balloon may be provided at the distal end of the catheter on the proximal side of the ultrasound transducer. The catheter may have lumens for inflation fluid, electrical wires,and a guide wire. A sheath that runs through the balloon may be used to isolate the electrical wires and guide wire from inflation fluid in the interior of the balloon.

Time to threshold ( TT), a safety parameter for heating by diagnostic ultrasound

Activities in the standardisation of medical ultrasonic imaging and monitoring devices have been undertaken to ensure the safe application and to provide the user with tools to perform risk-to-benefit analysis. Internationally, agreement has not been reached to implement a system based on a physical quantity such as temperature rise. Therefore, recently, the IEC Standard 60601-2-37 has adopted the thermal index ( TI) as a safety parameter. TI indicates conditions that are more likely than others to produce thermal effects. The models used to calculate TI are based on the equilibrium temperature rise for a stationary transducer. Ultrasound (US) is often applied during a short time at one place. To characterise the situation before equilibrium is reached, this study proposes a new parameter: TT (time to threshold). TT indicates the time after which a threshold temperature rise is exceeded. TT is calculated for some tissue models to illustrate the meaning of TT. TT indicates how long one piece of tissue can be insonated safely, provided the safe threshold is known. Using TT, higher intensities can be applied safely during a limited time. This paper illustrates the effects of short insonation times and the influence of the beam diameter. Questions that are critical to the introduction of TT as a safety parameter are discussed. (E-mail: j.lubbers@med.rug.nl)

High-frequency backscatter and attenuation measurements of porcine erythrocyte suspensions between 30–90 MHz

There are now diagnostic ultrasonic imaging devices that operate at very high frequencies (VHF) of 20 MHz and beyond for clinical applications in ophthalmology, dermatology and vascular surgery. To be able to better interpret these images and to further the development of these devices, knowledge of ultrasonic attenuation and scattering of biologic tissues, such as blood, in the high-frequency range is crucial. VHF attenuation and backscatter experiments were made on porcine red blood cell (RBC) suspensions, for which much data on attenuation and backscatter can be found in the literature in the lower frequency range. Attenuation and backscatter at hematocrits of 6%, 10%, 15%, 20%, 25% and 30% from 30 to 90 MHz were measured using a modified substitution method that allows the utilization of focused transducers. The results show that the attenuation coefficient from all suspensions increased linearly with frequency and the backscatter coefficient for low hematocrit suspensions was found to have a maximum between 10% and 15%. At higher hematocrits, a decrease in the frequency-dependence was observed, possibly indicating that Rayleigh scattering is no longer valid because the wavelength in the VHF range is comparable to the size of a porcine RBC.

Ultrasonic scattering by blood: theories, experimental results and biomedical applications

In this paper, theoretical and experimental efforts that have been undertaken to better understand the phenomenon of ultrasonic scattering in blood will be reviewed. This subject is of interest in biology and medicine because the echoes generated by blood are used to extract blood velocity by ultrasonic Doppler flow and imaging devices. In the course of these investigations it became clear that ultrasonic scattering from blood is dependent upon such hematological and hemodynamic properties of blood as hematocrit, plasma protein concentration, flow rate and flow cycle duration. Several aspects of these experimental results have been successfully modeled by recent theoretical developments. An unexpected consequence of these efforts is that ultrasound appears to be a viable tool for blood flow visualization and hemodynamic measurements. Two unique hemodynamic phenomena that have never been reported in the hemodynamic literature have been observed: the black hole, a low echogenic zone in the center stream of whole blood flowing in a blood vessel under steady flow and the collapsing ring, an echogenic ring appearing near the periphery of a vessel at the beginning of a flow cycle, converging toward the center, and eventually collapsing during pulsatile flow. Similar observations have been made during clinical scanning of patients.