Medical Ultrasound Imaging
Thursday, 21 November 2024
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From Philips Medical Systems;Introduced in June 2005, 'one of the less expensive and more dedicated' ultrasound systems.
Device Information and Specification
CONFIGURATION
LCD monitor
Broadband, convex, linear,
digital beamformer and focal tuning IMAGING OPTIONS
OPTIONAL PACKAGE
DICOM, etc.
STORAGE, CONNECTIVITY, OS
HDD, CD, USB, optionalMOD and DICOM 3.0
DATA PROCESSING
256-digitally processed channels
H*W*D inch.
58 * 20 * 32
WEIGHT
135 lbs.
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From Philips Medical Systems;'It's better than ever, inside and out − the new Philips HDI 5000 system brings together new ergonomics, a boost in processing power and the revolutionary technologies of the HDI 5000 system.' Specifications for this system will be available soon. •
Harmonic imaging relies on detection of harmonics of the transmitted
frequency produced by bubble oscillation. This method is widely available on ultrasound scanners and uses the same array transducers as conventional imaging. A major limitation of the use of ultrasound contrast agents is the problem that signals from the microbubbles are mixed with those from tissue. Echoes from solid tissue and red blood cells are suppressed by harmonic imaging. In harmonic mode, the system transmits at one frequency, but is tuned to receive echoes preferentially at double that frequency, and the second harmonic echoes from the place of the bubble. Typically, the transmit frequency lies between 1.5 and 3 MHz and the receive frequency is selected by means of a bandpass filter whose center frequency lies between 3 and 6 MHz. Color Doppler and real-time harmonic spectral Doppler modes have also been implemented and show a level of tissue motion suppression not available in conventional modes. See also Harmonic B-Mode Imaging, and Harmonic Power Doppler.  Further Reading: Basics:
News & More:
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The earliest introduction of vascular ultrasound contrast agents (USCA) was by Gramiak and Shah in 1968, when they injected agitated saline into the ascending aorta and cardiac chambers during echocardiographic to opacify the left heart chamber. Strong echoes were produced within the heart, due to the acoustic mismatch between free air microbubbles in the saline and the surrounding blood.
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In 1880 the Curie brothers discovered the piezoelectric effect in quartz. Converse piezoelectricity was mathematically deduced from fundamental thermodynamic principles by Lippmann in 1881.
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In 1917, Paul Langevin (France) and his coworkers developed an underwater sonar system (called hydrophone) that uses the piezoelectric effect to detect submarines through echo location.
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In 1935, the first RADAR system was produced by the British physicist Robert Watson-Wat. Also about 1935, developments began with the objective to use ultrasonic power therapeutically, utilizing its heating and disruptive effects on living tissues. In 1936, Siemens markets the first ultrasonic therapeutic machine, the Sonostat.
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Shortly after the World War II, researchers began to explore medical diagnostic capabilities of ultrasound. Karl Theo Dussik (Austria) attempted to locate the cerebral ventricles by measuring the transmission of ultrasound beam through the skull. Other researchers try to use ultrasound to detect gallstones, breast masses, and tumors. These first investigations were performed with A-mode.
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Shortly after the World War II, researchers in Europe, the United States and Japan began to explore medical diagnostic capabilities of ultrasound. Karl Theo Dussik (Austria) attempted to locate the cerebral ventricles by measuring the transmission of ultrasound beam through the skull. Other researchers, e.g. George Ludwig (United States) tried to use ultrasound to detect gallstones, breast masses, and tumors. This first experimentally investigations were performed with A-mode. Ultrasound pioneers contributed innovations and important discoveries, for example the velocity of sound transmission in animal soft tissues with a mean value of 1540 m/sec (still in use today), and determined values of the optimal scanning frequency of the ultrasound transducer.
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In the early 50`s the first B-mode images were obtained. Images were static, without gray-scale information in simple black and white and compound technique. Carl Hellmuth Hertz and Inge Edler (Sweden) made in 1953 the first scan of heart activity. Ian Donald and Colleagues (Scotland) were specialized on obstetric and gynecologic ultrasound research. By continuous development it was possible to study pregnancy and diagnose possible complications.
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After about 1960 two-dimensional compound procedures were developed. The applications in obstetric and gynecologic ultrasound boomed worldwide from the mid 60's with both, A-scan and B-scan equipment. In the late 60's B-mode ultrasonography replaced A-mode in wide parts.
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In the 70's gray scale imaging became available and with progress of computer technique ultrasonic imaging gets better and faster.
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In the 90's, high resolution scanners with digital beamforming, high transducer frequencies, multi-channel focus and broad-band transducer technology became state of the art. Optimized tissue contrast and improved diagnostic accuracy lead to an important role in breast imaging and cancer detection. Color Doppler and Duplex became available and sensitivity for low flow was continuously improved.
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Actually, machines with advanced ultrasound system performance are equipped with realtime compound imaging, tissue harmonic imaging, contrast harmonic imaging, vascular assessment, matrix array transducers, pulse inversion imaging, 3D and 4D ultrasound with panoramic view.
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Ultrasound contrast agents (USCAs) improve the sensitivity of various ultrasound applications. They usually stay within the vascular space and can be injected several times. Nevertheless the contrast enhancement is limited caused by physiologic clearance and bubble destruction. Different injection techniques to improve the imaging:
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Bolus injection generally results in a more or less prolonged blooming phase and a relatively short enhancing period of approximately 2- to 3 minutes.
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Slow injection provides markedly prolonged enhancement by minimizing over-contrast artifacts.
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Continuous perfusion achieves stable and uniform enhancement, lasting until the infusion is stopped.
Continuous infusion yield a steady-state concentration of the USCAs, greater examination time with optimal enhancement, avoid bloom and possibly other artifacts. Continuous infusion also allows the sonographer to optimize the effective dose individually during the examination. See also Power Modulation. Further Reading: News & More: Result Pages : | Share This Page     Look Ups |
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[last update: 2023-11-06 01:42:00]