This method makes it possible to differentiate between normal and diseased tissues. Sick tissues will be observed in a brighter shade. Traditional cardiac ultrasound uses the transthoracic pathway, that is, the heart is analyzed through the spaces that are located between the ribs. Cardiac ultrasound is obtained by an apparatus consisting of three basic elements:.
Transducer: A transducer is a device capable of transforming or converting a certain manifestation of input energy into a different output, but of very small values in relative terms with respect to a generator. Computer: is responsible for analyzing and managing the data obtained by the transducer, converting them into images, recording and reproducing them on the screen, as well as performing all kinds of measurements and processing data that will help us obtain the clinical diagnosis.
Display or Monitor: Essentially defined as screen to a surface, which has flat and smooth qualities designed with various materials, the function of it is to facilitate the projection of images in real time, allowing us to see what is happening inside the body at that precise moment.
The development of the first diagnostic equipment in medicine began at the end of World War II. This exploration was conducted by American, Japanese and European researchers who worked in parallel to manufacture prototypes of medical diagnostic equipment in mode A Analog , and later in mode B Bright with analogue imaging. The first ultrasound apparatus was developed in and perfected in , which was when it was possible to acquire images in real time, being one of the most important factors for the wide use of ultrasonography.
In , ultrasound was used to indicate the presence of fluid introduced into the peritoneal cavity of corpses. Although it is a clinical study that has many advantages, it also has some disadvantages, which are:. Information obtained by ultrasound may be confused and unnecessary biopsies or surgeries that could affect the patient may be confused.
Ultrasound equipment needs to be manipulated by a human being so that it can operate and interpret the results. It is limited for visualization of deeper structures patients of increased physical contexture, does not cross bone structures, and does not allow analysis of intra-articular structures.
First the patient lies down on a stretcher with the part of the body where the test will be uncovered. Then the health professional applies a special gel over the area where the patient will have the ultrasound done. Once the gel has been applied, the transducer is positioned in the area of the body to be analyzed and movements begin in order to locate the organ and obtain the desired image.
By means of the transducer, sound waves are sent to the body, which are so sharp that they cannot be perceived by the patient. Technicians may also save short video loops of the images. Doppler ultrasound is a special application of the ultrasound technique. Doppler measures the speed and direction of blood cells as they move through blood vessels. Like the changing pitch of a train's whistle as the locomotive passes, movement of blood cells changes the pitch of the reflected sound waves.
Scientists refer to this the Doppler Effect. A computer collects and processes the sounds to color pictures and graphs that represent the flow of blood through the blood vessels. There are two main types of medical ultrasounds: diagnostic ultrasound and therapeutic ultrasound. Diagnostic ultrasounds help doctors diagnose patients by producing images of internal fluids, tissues and organs.
Therapeutic ultrasounds use the power of sound energy to interact with body tissues in a way that modifies or destroys the tissue. Ultrasound specialists use therapeutic ultrasounds to move or push tissue, heat tissue, dissolve blood clots or deliver drugs to specific locations within a patient's body. Ultrasound professionals can also use therapeutic ultrasounds with very high-intensity beams to destroy diseased or abnormal tissues, such as tumors, without the need for surgery.
While ultrasound is an advanced medical technology today, its roots go all the way back to , when physiologist Lazzaro Spallanzani was the first person to study echolocation among bats. This echolocation, which is the use of sound waves to locate objects, is the basis of ultrasound physics. In , brothers Jacques and Pierre Currie discover piezoelectricity, in which they used probes to emit and receive sound waves. In , the sinking of the Titanic inspired physicist Paul Langevin to invent a device that could detect objects at the bottom of the sea.
He eventually invented the hydrophone, now recognized as the world's transducer. Doctors began to use ultrasound, also known as sonography, as a form of physical therapy in the s through the s. Neurologist Karl Dussik started using ultrasound for medical diagnosis in hopes of detecting brain tumors in Doctors then started using ultrasound for a wide variety of uses, such as for detecting gallstones and breast tumors.
Other advances include handheld transducers, Doppler, three-dimensional 3D imaging, and use during other procedures. Ultrasound scans are used to evaluate fetal development, and they can detect problems in the liver, heart, kidney, or abdomen. They may also assist in performing certain types of biopsy.
The person who performs an ultrasound scan is called a sonographer, but the images are interpreted by radiologists, cardiologists, or other specialists. Ultrasound is sound that travels through soft tissue and fluids, but it bounces back, or echoes, off denser surfaces. This is how it creates an image. For diagnostic uses, the ultrasound is usually between 2 and 18 megahertz MHz. Higher frequencies provide better quality images but are more readily absorbed by the skin and other tissue, so they cannot penetrate as deeply as lower frequencies.
Ultrasound will travel through blood in the heart chamber, for example, but if it hits a heart valve, it will echo, or bounce back. It will travel straight through the gallbladder if there are no gallstones , but if there are stones, it will bounce back from them. This bouncing back, or echo, gives the ultrasound image its features.
Varying shades of gray reflect different densities. Some very small transducers can be placed onto the end of a catheter and inserted into blood vessels to examine the walls of blood vessels. Ultrasound is commonly used for diagnosis, for treatment, and for guidance during procedures such as biopsies. It can be used to examine internal organs such as the liver and kidneys, the pancreas, the thyroid gland, the testes and the ovaries, and others.
An ultrasound scan can reveal whether a lump is a tumor. This could be cancerous, or a fluid-filled cyst. It can help diagnose problems with soft tissues, muscles, blood vessels, tendons, and joints. It is used to investigate a frozen shoulder , tennis elbow , carpal tunnel syndrome , and others.
Doppler ultrasound can assess the flow of blood in a vessel or blood pressure. It can determine the speed of the blood flow and any obstructions. An echocardiogram ECG is an example of Doppler ultrasound. It can be used to create images of the cardiovascular system and to measure blood flow and cardiac tissue movement at specific points.
A Doppler ultrasound can assess the function and state of cardiac valve areas, any abnormalities in the heart, valvular regurgitation, or blood leaking from valves, and it can show how well the heart pumps out blood.
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