One enables the device to detect tiny blood vessels; another, called elastography, was developed to examine the liver, and can help measure the density of placental tissue.
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For example, cancerous tumours will often be harder than the surrounding tissue, and diseased livers are stiffer than healthy ones. There are several elastographic techniques based on the use of ultrasound, magnetic resonance imaging and tactile imaging. The wide clinical use of ultrasound elastography is a result of the implementation of technology in clinical ultrasound machines. Main branches of ultrasound elastography include Quasistatic Elastography/Strain Imaging, Shear Wave Elasticity Imaging (SWEI), Acoustic Radiation Force Impulse imaging (ARFI), Supersonic Shear Imaging (SSI), and Transient Elastography.
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Elastography is able to overcome many these challenges and improve on the benefits of palpation. Elastography is a relatively new technology and entered the clinic primarily in the last decade. The most prominent techniques use ultrasound or magnetic resonance imaging (MRI) to make both the stiffness map and an anatomical image for comparison.
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Magnetic resonance elastography (MRE) is a non-invasive medical imaging technique that measures the stiffness of soft tissues by generating shear waves in tissue, imaging their propagation using MRI, and processing the images to generate a stiffness map (elastogram). It is one of the most commonly used elastography techniques. MRE was first described by Muthupillai et al. in 1995.
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3D tactile image (C) is composed from 2D pressure maps (B) recorded in the process of tissue phantom examination (A). Elastography is a relatively new imaging modality that maps the elastic properties of soft tissue. This modality emerged in the last two decades. Elastography is useful in medical diagnoses, as elasticity can discern healthy from unhealthy tissue for specific organs/growths.
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Other applications may be in medical sonography and elastography measuring the stress or pressure level in relevant elastic tissue types (e.g. ), enhancing non-invasive diagnostics.
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Ultrasound is also used for elastography, which is a relatively new imaging modality that maps the elastic properties of soft tissue. This modality emerged in the last two decades. Elastography is useful in medical diagnoses as it can discern healthy from unhealthy tissue for specific organs/growths. For example, cancerous tumors will often be harder than the surrounding tissue, and diseased livers are stiffer than healthy ones.
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Diagnostic anatomic ultrasound looks at the anatomy whereas diagnostic functional ultrasound records information such as blood flow or tissue characteristics. A specific functional form of ultrasound is elastography which measures and displays the relative elasticity of tissues, which can be used to differentiate tumors from healthy tissue. Recent studies have shown that shear wave elastography in primary invasive breast carcinoma could be useful for indicating axillary lymphadenopathy. Ultrasound is also used surgically.
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In the last decade a steady increase of activities in the field of elastography is observed demonstrating successful application of the technology in various areas of medical diagnostics and treatment monitoring.
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Conventional ultrasonography (lower image) and elastography (supersonic shear imaging; upper image) of papillary thyroid carcinoma, a malignant cancer. The cancer (red) is much stiffer than the healthy tissue. Nowadays, the medical imaging modality of elastography can also be used to determine the stiffness of tissues. Manual palpation suffers from several important limitations: it is limited to tissues accessible to the physician's hand, it is distorted by any intervening tissue, and it is qualitative but not quantitative.
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A number of different tests are available to determine the degree of cirrhosis present. Transient elastography (FibroScan) is the test of choice, but it is expensive. Aspartate aminotransferase to platelet ratio index may be used when cost is an issue.
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During last decade, most of his research activities and publications were on the various medical applications a branch of elastography called mechanical imaging (a.k.a. tactile imaging), developed by Sarvazyan with Vladimir Egorov.Sarvazyan AP. Mechanical imaging: a new technology for medical diagnostics. Int.
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Sarvazyan A. Diversity of biomedical applications of acoustic radiation force. Review. Ultrasonics 2010, 50(2):230-4.Sarvazyan A, Hall TJ, Urban MW, Fatemi M, Aglyamov SR, Garra BS. An overview of Elastography–an emerging branch of medical imaging. Current Medical Imaging Reviews, 2011, 7(4):255-282.
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He has over 100 U.S. and international patents and invention certificates. Sarvazyan is the co-founder of several companies specializing in elastography: ProUroCare Medical Inc.(Golden Valley, MN, 1999), Medical Tactile, Inc. (Los Angeles, CA, 2000), SuperSonic Imagine (Aix-en-Province, France, 2005) and Advanced Tactile Imaging, Inc.
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He also pioneered innovative medical imaging methods: transient elastography, supersonic shear imaging and multi-wave imaging that are now implemented by several companies. Six companies with close to 400 employees have been created from his research: Echosens,Echosens Sensitive Object,SensitiveObject Supersonic Imagine, Time Reversal Communications, Cardiawave, and GreenerWave.
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This range has shorter wavelengths which allow better resolution in imaging technologies. Medical applications such as ultrasonography and elastography rely on the ultrasonic frequency range. On the other end of the spectrum, the lowest frequencies are known as the infrasonic range. These frequencies can be used to study geological phenomena such as earthquakes.
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Quantitative shear wave elastography in primary invasive breast cancers, based on collagen-S100A4 pathology, indicates axillary lymph node metastasis. Quant Imaging Med Surg. 2020;10(3):624-633. Not only does overexpression of S100A4 contribute to the formation of various cancers, but it also contributes to pathological factors associated with cancer and its progression.
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This device could be used in preventive healthcare to protect against skin cancer. She was supported by the Office of Naval Research to develop an interferometric optical biosensor. The proposed biosensor is able to detect DNA and bacteria. She developed a high-resolution polarimetric elastography instrument to characterise the mechanical properties of visco-elastic materials.
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Beginning in the late 80s, a significant part of Sarvazyan's research activities were on the problems of elastography, an emerging technology of medical diagnostics. In 1991–1992, in collaboration with the University of Michigan, Ann Arbor, Sarvazyan conducted pioneering experiments on MRI and ultrasonic elastography.Fowlkes J, Emelianov S, Pipe J, Carson P, Adler R, Sarvazyan A, Skovoroda A. Possibility of cancer detection through measurement of elasticity properties.
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On the other hand, acoustic wave equations based on fractional derivative viscoelastic models are applied to describe the power law frequency dependent acoustic attenuation. Chen and Holm proposed the positive fractional derivative modified Szabo's wave equation and the fractional Laplacian wave equation. See Holm S., Näsholm, S. P., "Comparison of Fractional Wave Equations for Power Law Attenuation in Ultrasound and Elastography," Ultrasound Med. Biol., 40(4), pp.
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Their main aims are to characterize the risk of malignancy of nodules to better select nodules to submit to fine-needle aspiration cytology. Another imaging modality, which is ultrasound elastography, is also useful in diagnosing thyroid malignancy especially for follicular thyroid cancer. However, it is limited by the presence of adequate amount of normal tissue around the lesion, calcified shell around a nodule, cystic nodules, coalescent nodules.
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Since the early 2000s several research studies have been conducted to determine if there was a way to visualize myofascial trigger points using tools such as ultrasound imaging and magnetic resonance elastography. Several of these studies have been dismissed under meta- analysis. Another synthetic literature review expressed more optimism about the validity of imaging for myofascial trigger points, but admitted small sample sizes of the reviewed studies.
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Using B-mode imaging, assessment of renal anatomy is easily performed, and US is often used as image guidance for renal interventions. Furthermore, novel applications in renal US have been introduced with contrast-enhanced ultrasound (CEUS), elastography and fusion imaging. However, renal US has certain limitations, and other modalities, such as CT (CECT) and MRI, should always be considered as supplementary imaging modalities in the assessment of renal disease.
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A type of ultrasound examination to measure tissue stiffness, which is used to detect tumours, is elastography. Breast ultrasound is also used to perform fine-needle aspiration biopsy and ultrasound-guided fine- needle aspiration of breast abscesses. Some women prefer breast ultrasound over mammography because they dislike the pain felt during squeezing or fixing of breast done during mammography for X-ray views. Breast ultrasound is painless procedure.
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Alternatives include breast ultrasonography, CT scans, PET scans, scintimammography, elastography, thermography, ductal lavage, and experimental screening protocols, some of which hope to identify biomarkers for breast cancer (molecules that appear in the blood when breast cancer begins). Ovarian cancer screening usually involves ultrasonography of the pelvic region, typically twice a year. Women may also use a blood test for CA-125 and clinical pelvic exams. The blood test has relatively poor sensitivity and specificity for ovarian cancer.
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In the study, 2.5% of 4,000 people born in 1991 and 1992 were found by ultrasound scanning at the age of 18 to have non-alcoholic fatty liver disease; five years later transient elastography (fibroscan) found over 20% to have the fatty deposits on the liver of steatosis, indicating non-alcoholic fatty liver disease; half of those were classified as severe. The scans also found that 2.4% had the liver scarring of fibrosis, which can lead to cirrhosis.
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Grant projects on gene polymorphism in cirrhosis, elastography and fatty liver have been adopted. For the first time in Azerbaijan, it was used by stem cells for liver disease. He has been active in scientific and organizational work in Azerbaijan and around the world. In Azerbaijan he actively participated in defining and promoting pillar priorities of medical science (stem cells and regenerative medicine, genomics, molecular biology, high technologies and medicine, evidence-based medicine, translational medicine, etc.).
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Symptoms of muscle diseases may include weakness, spasticity, myoclonus and myalgia. Diagnostic procedures that may reveal muscular disorders include testing creatine kinase levels in the blood and electromyography (measuring electrical activity in muscles). In some cases, muscle biopsy may be done to identify a myopathy, as well as genetic testing to identify DNA abnormalities associated with specific myopathies and dystrophies. A non-invasive elastography technique that measures muscle noise is undergoing experimentation to provide a way of monitoring neuromuscular disease.
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In Bristol University's study Children of the 90s, 2.5% of 4,000 people born in 1991 and 1992 were found by ultrasound scanning at the age of 18 to have non-alcoholic fatty liver disease; five years later transient elastography (fibroscan) found over 20% to have the fatty deposits on the liver of steatosis, indicating non-alcoholic fatty liver disease; half of those were classified as severe. The scans also found that 2.4% had the liver scarring of fibrosis, which can lead to cirrhosis.
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In 2008, SIUI developed the real-time 3D/4D technology, and released a series of real-time 3D/ 4D color Doppler systems. E: Elastography. SIUI develops and manufactures a variety of ultrasound imaging systems and accessories for both human and veterinary use, and NDT equipment including phased-array ultrasonic flaw detector, conventional flaw detector, thickness gauge, probes and accessories. The company is currently organized into three product category divisions: ultrasound imaging systems, medical X-Ray imaging products, and non- destructive testing instruments.
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In Bristol University's study Children of the 90s, 2.5% of 4,000 people born in 1991 and 1992 were found by ultrasound scanning at the age of 18 to have non-alcoholic fatty liver disease; five years later transient elastography (fibroscan) found over 20% to have the fatty deposits on the liver of steatosis, indicating non-alcoholic fatty liver disease; half of those were classified as severe. The scans also found that 2.4% had the liver scarring of fibrosis, which can lead to cirrhosis.
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A hepatogram is a medical imaging examation of the liver. It is done via magnetic resonance imaging and consists of liver fibrosis and inflammation assessment, as well as steatosis grading. The current imaging protocol for a hepatogram is magnetic resonance elastography for fibrosis and inflammation assessment, and proton density fat fraction for steatosis measurement. A hepatogram is seen as a more accurate and noninvasive alternative to liver biopsy, and has emerged as "the reference standard for non-invasive diagnosis of liver fibrosis".
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Ultrasound tissue elastography is a method to determine tissue health, as pathologies have been noted to increase the elasticity of tissue. In 2015, a tissue-like agar-based phantom had been reported to be useful in compression elastographical diagnosis of breast cancer. The scientists replicated the clinical appearance of conditions such as fibroadenoma and invasive ductal carcinoma in the phantom breast and compared elastographic and sonographic images. Additionally, a recipe for the formation of a semi-compressible phantom breast with liquid rubber has been reported.
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In molecular ultrasonography, the technique of acoustic radiation force (also used for shear wave elastography) is applied in order to literally push the targeted microbubbles towards microvessels wall; firstly demonstrated by Dr Paul Dayton in 1999. This allows maximization of binding to the malignant tumor; the targeted microbubbles being in more direct contact with cancerous biomolecules expressed at the inner surface of tumoral microvessels. At the stage of scientific preclinical research, the technique of acoustic radiation force was implemented as a prototype in clinical ultrasound systems and validated in vivo in 2D and 3D imaging modes.
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FLD is the most common cause of abnormal liver function tests in the United States. Fatty liver is more prevalent in Hispanic people than white, with black people having the lowest susceptibility. In the study of Children of the 90s, 2.5% born in 1991 and 1992 were found by ultrasound at the age of 18 to have non- alcoholic fatty liver disease; five years later transient elastography (fibroscan) found over 20% to have the fatty deposits on the liver, indicating non-alcoholic fatty liver disease; half of those were classified as severe. The scans also found that 2.4% had the liver scarring, which can lead to cirrhosis.
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Strain–encoded magnetic resonance imaging (SENC-MRI) is a magnetic resonance imaging technique for imaging the strain of deforming tissue. It is undergoing testing to diagnose some heart diseases, particularly congenital right ventricle dysfunctions, which are difficult to diagnose. It is an improvement on magnetic resonance elastography in that it has a faster imaging time, and less post-processing time, to turn the acquired data into a useful image. To use the technique, the gradient coils in the MRI equipment need to be driven with special pulse sequences, designed for specific tissues, that "tags" deformation of the tissue, such that tissue that deforms more is brighter, or darker, as needed.
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When a force is applied, these materials elastically store and release energy, which does not result in energy loss in the form of heat. Yet, MRE and other elastography imaging techniques typically utilize a mechanical parameter estimation that assumes biological tissues to be linearly elastic and isotropic for simplicity purposes. The effective shear modulus \mu can be expressed with the following equation: \mu=E/[2(1+ u)] where E is the elastic modulus of the material and u is the Poisson’s ratio. The Poisson’s ratio for soft tissues is approximated to equal 0.5, resulting in the ratio between the elastic modulus and shear modulus to equal 3.
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These diagnostic techniques are often performed in combination with general pathology procedures and are themselves often essential to developing new understanding of the pathogenesis of a given disease and tracking the progress of disease in specific medical cases. Examples of important subdivisions in medical imaging include radiology (which uses the imaging technologies of X-ray radiography) magnetic resonance imaging, medical ultrasonography (or ultrasound), endoscopy, elastography, tactile imaging, thermography, medical photography, nuclear medicine and functional imaging techniques such as positron emission tomography. Though they do not strictly relay images, readings from diagnostics tests involving electroencephalography, magnetoencephalography, and electrocardiography often give hints as to the state and function of certain tissues in the brain and heart respectively.
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As a discipline and in its widest sense, it is part of biological imaging and incorporates radiology, which uses the imaging technologies of X-ray radiography, magnetic resonance imaging, ultrasound, endoscopy, elastography, tactile imaging, thermography, medical photography, nuclear medicine functional imaging techniques as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Measurement and recording techniques that are not primarily designed to produce images, such as electroencephalography (EEG), magnetoencephalography (MEG), electrocardiography (ECG), and others, represent other technologies that produce data susceptible to representation as a parameter graph vs. time or maps that contain data about the measurement locations. In a limited comparison, these technologies can be considered forms of medical imaging in another discipline.
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Back in 2000, Nuru Bayramov returned to Azerbaijan, where he previously worked as an associate professor at the Azerbaijan Medical University, and currently head of the Department of I Surgical Diseases. The main areas of his research during this period are liver resection, liver and kidney transplantation, laparoscopic and metabolic surgery, stem cells and genetic studies. Under his leadership doctoral thesis on topics of laparoscopic appendectomy, laparoscopic fundoplication, laparoscopic bile duct exploration, laparoscopic hernia repair, simultaneuse laproscopic surgery were defended. At present doctoral thesis on topics such as biliary complications, microRNA, histones and hepatic disfunctions after liver transplantation, iodine polymers in thyroid pathology, elastography in liver pathology, bariatric surgery in obesity are continued.
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While not widespread amongst elastography methods, computerized palpation is of interest here because it essentially uses palpation to measure the stiffness, whereas other techniques will obtain data using other methods. Computerized palpation is also called "Tactile Imaging", "Mechanical imaging" or "Stress imaging", is a medical imaging modality that translates the sense of touch into a digital image. The tactile image is a function of P(x,y,z), where P is the pressure on soft tissue surface under applied deformation and x,y,z are coordinates where pressure P was measured. Tactile imaging closely mimics manual palpation, since the probe of the device with a pressure sensor array mounted on its face acts similar to human fingers during clinical examination, slightly deforming soft tissue by the probe and detecting resulting changes in the pressure pattern.
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While it may provide less anatomical detail than techniques such as CT or MRI, it has several advantages which make it ideal in numerous situations, in particular that it studies the function of moving structures in real-time, emits no ionizing radiation, and contains speckle that can be used in elastography. Ultrasound is also used as a popular research tool for capturing raw data, that can be made available through an ultrasound research interface, for the purpose of tissue characterization and implementation of new image processing techniques. The concepts of ultrasound differ from other medical imaging modalities in the fact that it is operated by the transmission and receipt of sound waves. The high frequency sound waves are sent into the tissue and depending on the composition of the different tissues; the signal will be attenuated and returned at separate intervals.
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