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75-423: Under ultrasound guidance, the operator inserts a 16.5 gauge × 11.8″ (1.6 mm × 300 mm outer diameter) needle through the vaginal wall and into an ovarian follicle , taking care not to injure nearby organs and blood vessels. The other end of the needle is attached to a suction device . Once the follicle is entered, suction is carefully applied to aspirate follicular fluid containing cellular material, including

150-453: A hand over their nose and mouth, while using the other hand to push the victim's jaw up. The corpses had no visible injuries, and were supplied to medical schools for money. Compressive asphyxia (also called chest compression) is mechanically limiting expansion of the lungs by compressing the torso, preventing breathing. " Traumatic asphyxia " or "crush asphyxia" usually refers to compressive asphyxia resulting from being crushed or pinned under

225-406: A hand, pillow, or a plastic bag. Smothering can be either partial or complete, where partial indicates that the person being smothered is able to inhale some air, although less than required. In a normal situation, smothering requires at least partial obstruction of both the nasal cavities and the mouth to lead to asphyxia. Smothering with the hands or chest is used in some combat sports to distract

300-429: A large weight or force, or in a crowd crush . An example of traumatic asphyxia is a person who jacks up a car to work on it from below, and is crushed by the vehicle when the jack fails. Constrictor snakes such as boa constrictors kill through slow compressive asphyxia, tightening their coils every time the prey breathes out rather than squeezing forcefully. In cases of an adult co-sleeping with an infant ("overlay"),

375-419: A low oxygen atmosphere, or in a vacuum; environments where sufficiently oxygenated air is present, but cannot be adequately breathed because of air contamination such as excessive smoke. Other causes of oxygen deficiency include but are not limited to: Smothering is a mechanical obstruction of the flow of air from the environment into the mouth and/or nostrils, for instance, by covering the mouth and nose with

450-436: A mouse model), some authors have suggested that the dose of propofol administered during anesthesia should be limited, and also that the retrieved oocytes should be washed free of propofol. Anecdotal evidence suggests that certain airborne chemical contaminants and particles, especially volatile organic compounds (VOC), may be toxic to and impair the growth and development of embryos if present in sufficient concentrations in

525-581: A newborn infant long enough to cause apparent harm. It results most commonly from a drop in maternal blood pressure or interference during delivery with blood flow to the infant's brain . This can occur as a result of inadequate circulation or perfusion , impaired respiratory effort, or inadequate ventilation . There has long been a scientific debate over whether newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals , which have

600-489: A price of deeper tissue penetration. In anesthesiology , ultrasound is commonly used to guide the placement of needles when injecting local anesthetic solutions in the proximity of nerves identified within the ultrasound image (nerve block). It is also used for vascular access such as cannulation of large central veins and for difficult arterial cannulation . Transcranial Doppler is frequently used by neuro-anesthesiologists for obtaining information about flow-velocity in

675-466: A role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen. Classifications of different forms of asphyxia vary among literature, with differences in defining the concept of mechanical asphyxia being the most obvious. In DiMaio and DiMaio's 2001 textbook on forensic pathology, mechanical asphyxia

750-533: A similar mechanism are cave-ins , or when an individual is buried in sand, snow, dirt, or grain. In homicidal cases, the term burking is often ascribed to a killing method that involves simultaneous smothering and compression of the torso. The term "burking" comes from the method William Burke and William Hare used to kill their victims during the West Port murders . They killed the usually intoxicated victims by sitting on their chests and suffocating them by putting

825-500: A specific tumor or calculus is not an imaging mode. However, for positioning a treatment probe to focus on a specific region of interest, A-mode and B-mode are typically used, often during treatment. Compared to other medical imaging modalities, ultrasound has several advantages. It provides images in real-time, is portable , and can consequently be brought to the bedside. It is substantially lower in cost than other imaging strategies. Drawbacks include various limits on its field of view,

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900-405: A useful hint to treat patients with symptoms related to pelvic prolapse, double incontinence and obstructed defecation. It is also used to diagnose and, at higher frequencies, to treat (break up) kidney stones or kidney crystals ( nephrolithiasis ). Scrotal ultrasonography is used in the evaluation of testicular pain , and can help identify solid masses. Ultrasound is an excellent method for

975-446: A weight of approximately 450 kg or 1000 lbs). In cases where people have stacked up on each other in a human pile, it has been estimated that those at the bottom are subjected to around 380 kg (840 lbs) of compressive weight. "Positional" or "restraint" asphyxia is when a person is restrained and left alone prone, such as in a police vehicle, and is unable to reposition themself in order to breathe. The death can be in

1050-456: Is a common medical procedure. The need for intravenous access occurs in the outpatient laboratory, in the inpatient hospital units, and most critically in the Emergency Room and Intensive Care Unit. In many situations, intravenous access may be required repeatedly or over a significant time period. In these latter circumstances, a needle with an overlying catheter is introduced into the vein and

1125-489: Is a potentially catastrophic and not so rare complication. Additional complications may result from the administration of intravenous sedation or general anesthesia. These include asphyxia caused by airway obstruction , apnea , hypotension , and pulmonary aspiration of stomach contents. Propofol -based anesthetic techniques result in significant concentrations of propofol in follicular fluid. As propofol has been shown to have deleterious effects on oocyte fertilization (in

1200-421: Is an essential tool in cardiology , assisting in evaluation of heart valve function, such as stenosis or insufficiency , strength of cardiac muscle contraction, and hypertrophy or dilatation of the main chambers. ( ventricle and atrium ) Point of care ultrasound has many applications in emergency medicine . These include differentiating cardiac from pulmonary causes of acute breathlessness , and

1275-529: Is attributed to positional asphyxia. Therefore, passive deaths following custody restraint that are presumed to be the result of positional asphyxia may actually be examples of asphyxia occurring during the restraint process. Chest compression is a technique used in various grappling combat sports, where it is sometimes called wringing, either to tire the opponent or as complementary or distractive moves in combination with pinning holds , or sometimes even as submission holds . Examples of chest compression include

1350-437: Is called medical ultrasonography or simply sonography , or echography . The practice of examining pregnant women using ultrasound is called obstetric ultrasonography , and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine , a sonograph or an echograph . The visual image formed using this technique is called an ultrasonogram , a sonogram or an echogram . Ultrasound

1425-569: Is caused by pressure from outside the body restricting respiration. Similar narrow definitions of mechanical asphyxia have occurred in Azmak's 2006 literature review of asphyxial deaths and Oehmichen and Auer's 2005 book on forensic neuropathology. According to DiMaio and DiMaio, mechanical asphyxia encompasses positional asphyxia, traumatic asphyxia, and "human pile" deaths. In Shkrum and Ramsay's 2007 textbook on forensic pathology, mechanical asphyxia occurs when any mechanical means cause interference with

1500-522: Is composed of sound waves with frequencies greater than 20,000 Hz, which is the approximate upper threshold of human hearing. Ultrasonic images, also known as sonograms, are created by sending pulses of ultrasound into tissue using a probe . The ultrasound pulses echo off tissues with different reflection properties and are returned to the probe which records and displays them as an image. A general-purpose ultrasonic transducer may be used for most imaging purposes but some situations may require

1575-440: Is curable but must be treated to preserve health and fertility. There are two methods of performing pelvic sonography – externally or internally. The internal pelvic sonogram is performed either trans vaginally (in a woman) or transrectally (in a man). Sonographic imaging of the pelvic floor can produce important diagnostic information regarding the precise relationship of abnormal structures with other pelvic organs and it represents

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1650-419: Is from Ancient Greek α- "without" and σφύξις sphyxis , "squeeze" (throb of heart). Situations that can cause asphyxia include but are not limited to: airway obstruction , the constriction or obstruction of airways, such as from asthma , laryngospasm , or simple blockage from the presence of foreign materials; from being in environments where oxygen is not readily accessible: such as underwater, in

1725-435: Is not typically used because local anesthetic agents interfere with follicular cleavage and the technique requires multiple needle punctures. This technique must be done very delicately, without stimulating the uterus, so that contractions do not occur. Minimizing patient anxiety is desirable to favor efficacy. Follicular flushing has not been found to increase pregnancy rates , nor result in an increase in oocyte yield. On

1800-620: 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 be considered for supplementary imaging in assessing renal disease. Intravenous access, for the collection of blood samples to assist in diagnosis or laboratory investigation including blood culture, or for administration of intravenous fluids for fluid maintenance of replacement or blood transfusion in sicker patients,

1875-499: Is routinely used in urology to determine the amount of fluid retained in a patient's bladder. In a pelvic sonogram, images include the uterus and ovaries or urinary bladder in females. In males, a sonogram will provide information about the bladder, prostate , or testicles (for example to urgently distinguish epididymitis from testicular torsion ). In young males, it is used to distinguish more benign testicular masses ( varicocele or hydrocele ) from testicular cancer , which

1950-548: Is the initial imaging choice, avoiding radiation if possible, although it frequently needs to be followed by other imaging methods such as CT . Endoanal ultrasound is used particularly in the investigation of anorectal symptoms such as fecal incontinence or obstructed defecation . It images the immediate perianal anatomy and is able to detect occult defects such as tearing of the anal sphincter . Ultrasonography of liver tumors allows for both detection and characterization. Ultrasound imaging studies are often obtained during

2025-472: Is therefore not a true tomographic representation of the body. Three-dimensional imaging is done by combining B-mode images, using dedicated rotating or stationary probes. This has also been referred to as C-mode . An imaging technique refers to a method of signal generation and processing that results in a specific application. Most imaging techniques are operating in B-mode. Therapeutic ultrasound aimed at

2100-448: Is used at the bedside or examination table to evaluate a number of different lung abnormalities as well as to guide procedures such as thoracentesis , (drainage of pleural fluid (effusion)), needle aspiration biopsy, and catheter placement. Although air present in the lungs does not allow good penetration of ultrasound waves, interpretation of specific artifacts created on the lung surface can be used to detect abnormalities. Ultrasound

2175-488: Is used for imaging flow in the intracerebral arteries. Intravascular ultrasound ( IVUS ) uses a specially designed catheter with a miniaturized ultrasound probe attached to its distal end, which is then threaded inside a blood vessel. The proximal end of the catheter is attached to computerized ultrasound equipment and allows the application of ultrasound technology, such as a piezoelectric transducer or capacitive micromachined ultrasonic transducer , to visualize

2250-632: The Focused Assessment with Sonography for Trauma (FAST) exam , extended to include assessment for significant hemoperitoneum or pericardial tamponade after trauma ( EFAST ). Other uses include assisting with differentiating causes of abdominal pain such as gallstones and kidney stones . Emergency Medicine Residency Programs have a substantial history of promoting the use of bedside ultrasound during physician training. Both abdominal and endoanal ultrasound are frequently used in gastroenterology and colorectal surgery . In abdominal sonography,

2325-792: The Hillsborough disaster in 1989, where 97 Liverpool fans were crushed to death in an overcrowded terrace, 95 of the 97 from compressive asphyxia, 93 dying directly from it and 3 others from related complications; the 2021 Meron crowd crush where 45 died; the Astroworld Festival crowd crush in 2021, where 10 died; and the Seoul Halloween crowd crush in 2022, where at least 159 died during Halloween celebrations. In confined spaces, people are forced to push against each other; evidence from bent steel railings in several fatal crowd accidents has shown horizontal forces over 4500 N (equivalent to

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2400-425: The endothelium of blood vessels in living individuals. In the case of the common and potentially, serious problem of blood clots in the deep veins of the leg, ultrasound plays a key diagnostic role, while ultrasonography of chronic venous insufficiency of the legs focuses on more superficial veins to assist with planning of suitable interventions to relieve symptoms or improve cosmetics. Echocardiography

2475-467: The knee-on-stomach position ; or techniques such as leg scissors (also referred to as body scissors and in budō referred to as do-jime ; 胴絞, "trunk strangle" or "body triangle") where a participant wraps his or her legs around the opponent's midsection and squeezes them together. Pressing is a form of torture or execution using compressive asphyxia. Perinatal asphyxia is the medical condition resulting from deprivation of oxygen ( hypoxia ) to

2550-440: The transducer at the desired frequency. The frequencies can vary between 1 and 18 MHz , though frequencies up to 50–100 megahertz have been used experimentally in a technique known as biomicroscopy in special regions, such as the anterior chamber of the eye. Older technology transducers focused their beam with physical lenses. Contemporary technology transducers use digital antenna array techniques (piezoelectric elements in

2625-769: The absence of sonography. It is currently believed that the risk of delayed diagnosis is greater than the small risk, if any, associated with undergoing an ultrasound scan. However, its use for non-medical purposes such as fetal "keepsake" videos and photos is discouraged. Obstetric ultrasound is primarily used to: According to the European Committee of Medical Ultrasound Safety (ECMUS) Ultrasonic examinations should only be performed by competent personnel who are trained and updated in safety matters. Ultrasound produces heating, pressure changes and mechanical disturbances in tissue. Diagnostic levels of ultrasound can produce temperature rises that are hazardous to sensitive organs and

2700-595: The ambient atmosphere of an IVF incubator . Endometriosis seems to cause a challenge for TVOR that may have reflection on individual surgeon's performance rates for the procedure, independently from the diameter of a pre-existing ovarian endometrioma (OMA) or ovarian adhesions. Obesity is another factor that may present a challenge for the procedure. This technique was first developed by Pierre Dellenbach and colleagues in Strasbourg , France, and reported in 1984. Steptoe and Edwards used laparoscopy to recover oocytes when IVF

2775-599: The application and interpretation of medical imaging modalities, or by cardiologists in the case of cardiac ultrasonography ( echocardiography ). Sonography is effective for imaging soft tissues of the body. Superficial structures such as muscle , tendon , testis , breast , thyroid and parathyroid glands, and the neonatal brain are imaged at higher frequencies (7–18 MHz), which provide better linear (axial) and horizontal (lateral) resolution . Deeper structures such as liver and kidney are imaged at lower frequencies (1–6 MHz) with lower axial and lateral resolution as

2850-424: The basal cerebral vessels . In angiology or vascular medicine, duplex ultrasound (B Mode imaging combined with Doppler flow measurement) is used to diagnose arterial and venous disease. This is particularly important in potential neurologic problems , where carotid ultrasound is commonly used for assessing blood flow and potential or suspected stenosis in the carotid arteries , while transcranial Doppler

2925-578: The catheter is then inserted securely into the vein while the needle is withdrawn. The chosen veins are most frequently selected from the arm, but in challenging situations, a deeper vein from the neck ( external jugular vein ) or upper arm ( subclavian vein ) may need to be used. There are many reasons why the selection of a suitable vein may be problematic. These include, but are not limited to, obesity, previous injury to veins from inflammatory reaction to previous 'blood draws', previous injury to veins from recreational drug use. In these challenging situations,

3000-415: The chosen vein. Ultrasound training for intravenous cannulation is offered in most ultrasound training programs. The creation of an image from sound has three steps – transmitting a sound wave , receiving echoes , and interpreting those echoes. A sound wave is typically produced by a piezoelectric transducer encased in a plastic housing. Strong, short electrical pulses from the ultrasound machine drive

3075-490: The eggs are fully mature but just prior to rupture of the follicles . Injection of hCG as a trigger for ovulation confers a risk of ovarian hyperstimulation syndrome , especially in patients with polycystic ovary syndrome who have been hyperstimulated during previous assisted reproduction cycles. Complications of TVOR include injury to pelvic organs, hemorrhage , and infection. Occurring more often in lean patients with polycystic ovary syndrome, ovarian hemorrhage after TVOR

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3150-399: The embryo/fetus. Biological effects of non-thermal origin have been reported in animals but, to date, no such effects have been demonstrated in humans, except when a micro-bubble contrast agent is present. Nonetheless, care should be taken to use low power settings and avoid pulsed wave scanning of the fetal brain unless specifically indicated in high risk pregnancies. Figures released for

3225-464: The evaluation process of Fatty liver disease . Ultrasonography reveals a "bright" liver with increased echogenicity. Pocket-sized ultrasound devices might be used as point-of-care screening tools to diagnose liver steatosis. Gynecologic ultrasonography examines female pelvic organs (specifically the uterus , ovaries , and fallopian tubes ) as well as the bladder , adnexa , and pouch of Douglas . It uses transducers designed for approaches through

3300-595: The exchange of oxygen and carbon dioxide in the body. Similar broad definitions of mechanical asphyxia have occurred in Saukko and Knight's 2004 book on asphyxia, and Dolinak and Matshes' 2005 book on forensic pathology. According to Shkrum and Ramsay, mechanical asphyxia encompasses smothering, choking, positional asphyxia, traumatic asphyxia, wedging, strangulation and drowning. Sauvageau and Boghossian propose in 2010 that mechanical asphyxia should be officially defined as caused by "restriction of respiratory movements, either by

3375-415: The head and neck can be differentiated, evaluated, and managed with the help of diagnostic ultrasound and ultrasound-guided procedures. In neonatology , transcranial Doppler can be used for basic assessment of intracerebral structural abnormalities, suspected hemorrhage, ventriculomegaly or hydrocephalus and anoxic insults ( periventricular leukomalacia ). It can be performed through the soft spots in

3450-552: The heavy sleeping adult may move on top of the infant, causing compression asphyxia. In fatal crowd disasters, compressive asphyxia from being crushed against the crowd causes all or nearly all deaths, rather than blunt trauma from trampling. This is what occurred at the Ibrox disaster in 1971, where 66 Rangers fans died; the 1979 The Who concert disaster where 11 died; the Luzhniki disaster in 1982, when 66 FC Spartak Moscow fans died;

3525-407: The insertion of a catheter into a vein has been greatly assisted by the use of ultrasound. The ultrasound unit may be 'cart-based' or 'handheld' using a linear transducer with a frequency of 10 to 15 megahertz . In most circumstances, choice of vein will be limited by the requirement that the vein is within 1.5 cms. from the skin surface. The transducer may be placed longitudinally or transversely over

3600-423: The kidneys is essential in the diagnosis and management of kidney-related diseases. The kidneys are easily examined, and most pathological changes are distinguishable with ultrasound. It is an accessible, versatile, relatively economic, and fast aid for decision-making in patients with renal symptoms and for guidance in renal intervention. Using B-mode imaging , assessment of renal anatomy is easily performed, and US

3675-461: The lateral resolution decreases. Therefore, the wider the transducer width and the higher the frequency of ultrasound, the longer the Fresnel zone, and the lateral resolution can be maintained at a greater depth from the transducer. Ultrasound waves travel in pulses. Therefore, a shorter pulse length requires higher bandwidth (greater number of frequencies) to constitute the ultrasound pulse. As stated,

3750-443: The layers between different tissues or scattered from smaller structures. Specifically, sound is reflected anywhere where there are acoustic impedance changes in the body: e.g. blood cells in blood plasma , small structures in organs, etc. Some of the reflections return to the transducer. The return of the sound wave to the transducer results in the same process as sending the sound wave, in reverse. The returned sound wave vibrates

3825-442: The limited data available. TVOR is typically performed after ovarian hyperstimulation , where oocytes are pharmacologically stimulated to mature. When the ovarian follicles have reached a certain degree of development, induction of final oocyte maturation is performed, generally by an intramuscular or subcutaneous injection of human chorionic gonadotropin (hCG). TVOR is typically performed 34–36 hours after hCG injection, when

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3900-474: The lower abdominal wall, curvilinear and sector, and specialty transducers such as transvaginal ultrasound . Obstetrical sonography was originally developed in the late 1950s and 1960s by Sir Ian Donald and is commonly used during pregnancy to check the development and presentation of the fetus . It can be used to identify many conditions that could be potentially harmful to the mother and/or baby possibly remaining undiagnosed or with delayed diagnosis in

3975-399: The major organs of the abdomen such as the pancreas , aorta , inferior vena cava , liver , gall bladder , bile ducts , kidneys , and spleen may be imaged. However, sound waves may be blocked by gas in the bowel and attenuated to differing degrees by fat, sometimes limiting diagnostic capabilities. The appendix can sometimes be seen when inflamed (e.g.: appendicitis ) and ultrasound

4050-437: The neck, including the thyroid and parathyroid glands , lymph nodes , and salivary glands , are well-visualized by high-frequency ultrasound with exceptional anatomic detail. Ultrasound is the preferred imaging modality for thyroid tumors and lesions, and its use is important in the evaluation, preoperative planning, and postoperative surveillance of patients with thyroid cancer . Many other benign and malignant conditions in

4125-635: The need for patient cooperation, dependence on patient physique, difficulty imaging structures obscured by bone , air or gases, and the necessity of a skilled operator, usually with professional training. Sonography (ultrasonography) is widely used in medicine . It is possible to perform both diagnosis and therapeutic procedures , using ultrasound to guide interventional procedures such as biopsies or to drain collections of fluid, which can be both diagnostic and therapeutic. Sonographers are medical professionals who perform scans which are traditionally interpreted by radiologists, physicians who specialize in

4200-524: The newborn, respiratory distress syndrome, congenital pneumonia, meconium aspiration syndrome, and pneumothorax. A neonatal lung ultrasound score, first described by Brat et al., has been found to highly correlate with oxygenation in the newborn. In ophthalmology and optometry , there are two major forms of eye exam using ultrasound: Ultrasound is used to assess the lungs in a variety of settings including critical care, emergency medicine, trauma surgery, as well as general medicine. This imaging modality

4275-454: The oocyte are removed. Initially performed using transabdominal ultrasonography , TVOR is currently performed with a transvaginal ultrasound transducer with an attached needle. TVOR is performed in an operating room or a physician's office, with the (female) subject in the lithotomy position . TVOR is usually performed under procedural sedation , general anesthesia , paracervical block , or sometimes spinal anesthesia . Local anesthesia

4350-457: The oocyte. The suction device must maintain a pressure of -140 mmHg (necessary to aspirate rapidly, but not enough to damage the follicles) and a temperature of approximately 37 °C. The follicular fluid is delivered to a technician in the IVF laboratory to identify and quantify the ova. Once the ovarian follicles have been aspirated on one ovary, the needle is withdrawn and the procedure is repeated on

4425-455: The opponent, and create openings for transitions , as the opponent is forced to react to the smothering. In some cases, when performing certain routines, smothering is combined with simultaneous compressive asphyxia. One example is overlay, in which an adult accidentally rolls over onto an infant during co-sleeping , an accident that often goes unnoticed and is mistakenly thought to be sudden infant death syndrome . Other accidents involving

4500-479: The other hand, it requires a significantly longer operative time and more analgesia. Seminal fluid contains several proteins that interact with epithelial cells of the cervix and uterus , inducing active gestational immune tolerance . There are significantly improved outcomes when patients are exposed to seminal plasma around the time of oocyte retrieval, with statistical significance for clinical pregnancy , but not for ongoing pregnancy or live birth rates with

4575-414: The other ovary. It is not unusual to remove 20 oocytes as patients are generally hyperstimulated in advance of this procedure. After completion, the needle is withdrawn, and hemostasis is achieved. The procedure usually lasts 10–20 minutes. Once the extraction is done, the sample is analyzed in the microscope to select and carry out the oocyte decumulation, a process where the granulosa cells surrounding

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4650-675: The period 2005–2006 by the UK Government (Department of Health) show that non-obstetric ultrasound examinations constituted more than 65% of the total number of ultrasound scans conducted. Blood velocity can be measured in various blood vessels, such as middle cerebral artery or descending aorta , by relatively inexpensive and low risk ultrasound Doppler probes attached to portable monitors. These provide non-invasive or transcutaneous (non-piercing) minimal invasive blood flow assessment. Common examples are transcranial Doppler , esophageal Doppler and suprasternal Doppler . Most structures of

4725-581: The position of the body or by external chest compression", thus encompassing only positional asphyxia and traumatic asphyxia. If there are symptoms of mechanical asphyxia, it is necessary to call the Emergency Medical Services . In some countries, such as the US, there may also be self-acting groups of voluntary first responders who have been trained in first aid. In case of mechanical asphyxia, first aid can be provided on your own. In case of choking on

4800-451: The skull of a newborn infant ( Fontanelle ) until these completely close at about 1 year of age by which time they have formed a virtually impenetrable acoustic barrier to ultrasound. The most common site for cranial ultrasound is the anterior fontanelle. The smaller the fontanelle, the more the image is compromised. Lung ultrasound has been found to be useful in diagnosing common neonatal respiratory diseases such as transient tachypnea of

4875-413: The sound is focused either by the shape of the transducer, a lens in front of the transducer, or a complex set of control pulses from the ultrasound scanner, in the beamforming or spatial filtering technique. This focusing produces an arc-shaped sound wave from the face of the transducer. The wave travels into the body and comes into focus at a desired depth. Materials on the face of the transducer enable

4950-408: The sound to be transmitted efficiently into the body (often a rubbery coating, a form of impedance matching ). In addition, a water-based gel is placed between the patient's skin and the probe to facilitate ultrasound transmission into the body. This is because air causes total reflection of ultrasound; impeding the transmission of ultrasound into the body. The sound wave is partially reflected from

5025-409: The study of the penis , such as indicated in trauma, priapism, erectile dysfunction or suspected Peyronie's disease . Musculoskeletal ultrasound is used to examine tendons, muscles, nerves, ligaments, soft tissue masses, and bone surfaces. It is helpful in diagnosing ligament sprains, muscles strains and joint pathology. It is an alternative or supplement to x-ray imaging in detecting fractures of

5100-408: The tissues and organs, some more rapidly than others. There are many circumstances that can induce asphyxia, all of which are characterized by the inability of a person to acquire sufficient oxygen through breathing for an extended period of time. Asphyxia can cause coma or death. In 2015, about 9.8 million cases of unintentional suffocation occurred which resulted in 35,600 deaths. The word asphyxia

5175-499: The transducer and the transducer turns the vibrations into electrical pulses that travel to the ultrasonic scanner where they are processed and transformed into a digital image. To make an image, the ultrasound scanner must determine two characteristics from each received echo: Asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing . Asphyxia causes generalized hypoxia , which affects all

5250-449: The transducer produce echoes at different times) to enable the ultrasound machine to change the direction and depth of focus. Near the transducer, the width of the ultrasound beam almost equals to the width of the transducer, after reaching a distance from the transducer (near zone length or Fresnel zone ), the beam width narrows to half of the transducer width, and after that the width increases (far zone length or Fraunhofer's zone ), where

5325-472: The use of a specialized transducer. Most ultrasound examination is done using a transducer on the surface of the body, but improved visualization is often possible if a transducer can be placed inside the body. For this purpose, special-use transducers, including transvaginal , endorectal, and transesophageal transducers are commonly employed. At the extreme, very small transducers can be mounted on small diameter catheters and placed within blood vessels to image

5400-413: The vehicle, or following loss of consciousness to be followed by death while in a coma, having presented with anoxic brain damage. The asphyxia can be caused by facial compression, neck compression, or chest compression. This occurs mostly during restraint and handcuffing situations by law enforcement, including psychiatric incidents. The weight of the restraint(s) doing the compression may contribute to what

5475-412: The walls and disease of those vessels. The imaging mode refers to probe and machine settings that result in specific dimensions of the ultrasound image. Several modes of ultrasound are used in medical imaging: Most machines convert two-way time to imaging depth using as assumed speed of sound of 1540 m/s. As the actual speed of sound varies greatly in different tissue types, an ultrasound image

5550-487: The wrist, elbow and shoulder for patients up to 12 years ( Fracture sonography ). Quantitative ultrasound is an adjunct musculoskeletal test for myopathic disease in children; estimates of lean body mass in adults; proxy measures of muscle quality (i.e., tissue composition) in older adults with sarcopenia Ultrasound can also be used for needle guidance in muscle or joint injections , as in ultrasound-guided hip joint injection . In nephrology , ultrasonography of

5625-607: Was introduced, and laparoscopy was the major method of oocyte recovery until TVOR was introduced. Medical ultrasound Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound , as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons , muscles , joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine

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