What is ultrasound ?
Ultrasound is an advanced diagnostic technique. It is used for the diagnosis of diseases related to the internal organs. It comes under non-invasive diagnostic procedures. It is very helpful for the clinicians to diagnose and interpret the medical conditions. Due to development of this technique in the medical sector so many new discoveries has been occurred. In this article we will get through knowledge about this technique.
What is the scientific principle of behind the working of Ultrasound?
When any form of energy is applied to a quartz crystal it vibrates to produce waves. This wave strikes the various tissues and is reflected back to the quartz crystals produces a corresponding electric current. This current is further processed by the machine, to be displayed as images. Ultrasonography is used for tomographic imaging of both normal and abnormal soft tissue, To quantitate the movement of structures ,To access the patterns of blood flow. The concept is Developed from SONAR (sound navigation and ranging) systems used to detect submarines. The human ear detect sound frequencies 20-20000 Hz. sound above this range is called ultrasound. Most instruments used in diagnostic medicine use sound in the range of 1-20 MHz
What are the physical principles of ultrasound ?
Two main components of the ultrasound. These are behind the real working of the ultrasound.
1. Wavelength – distance travelled by ultrasound wave.
2. Frequency- it is the number of times a wave is repeated per second.
V= lf
V = velocity of sound
l = Waved length
f = frequency
Smaller the wave length, greater absorption of sound, greater resolution, lesser penetration. The penetration ability is controlled by the frequency of ultrasound wave. Shorter the frequency higher is the penetration, E.g. 2-3.5 MHz for scanning internal organs of large animals, 20-40 MHz for scanning superficial structures like skin, cornea, and lens.
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What are the modes of ultrasound ?
1. A-Mode (Amplitude mode)– Single Ultrasound beams is used in this mode of the diagnosis of ultrasound. The returning echoes are shown as peak along the horizontal axis. The height of the peak is directly proportional to the strength of the echo. gives information about the organ boundaries.
2. B– Mode- Returning echo is depicted as the dots Brightness Multiple Ultrasound beams are used. of the dot is directly proportional to the strength of the echo. called as the “Grey- Scale imaging”
3. 2D image- It is the most popular mode of display Same as A-mode. Brightness corresponding to amplitude of reflected sound. Brightness denote depth of organ. Most modern ultrasound devices are real time 2D imaging systems.
What is the procedure of performing ultrasound ?
First the organ to be scanned is decided with the knowledge of the topographic anatomy. Use the ‘acoustic window’ i.e. easiest and the nearest site for passing the ultrasound wave into the desired organs. This acoustic window used for performing the ultrasound. Apply the gel or mineral oil for facilitating the movement of the probe over the surface and also for the easy passage of the sound waves.
Common terms used in the ultrasonography ?
1. Anechoic- Never use dense, opaque, lucent
2. Echogenic-No returning echoes= black (acellular fluid),some shade of grey will be seen due to returning echoes.
3. Hyper-echoic/echogenic/echo rich– Bright images on dark screen is given by highly reflective interface such as bone or air.
4. Hypo- echoic/echo poor– Grey image on dark screen which is given by interface of moderate reflection.
5. Anechoic/echo lucent/echo free– Black image due to absence of echo. It denotes the complete transmission of the sound as through the fluids.
What are the use of ultrasound ?
- Lithiotrypsy– Its is the procedure in which ultrasound waves are used to to break up the stones in the kidney and parts of the ureter. It is very useful for the patients who are suffering from the kidney stone. After break up of the stones small pieces of the stone comes out in the urine and patients get relief.
- Discriminating Nature of Tissue– Ultrasounds are used for the discrimination of the soft tissues. This used for the diagnosis of the different kind of cancerous growths in internal organs.
- Ultrasound Therapy– Ultrasound therapy is used for different types of the disease disorders. It is a kind of radiation therapy. By using this therapy many people get benefited.
- Ocular Examination– Now a days due to development in the science and use of ultrasound. This method is used for the diagnosis of different eye related conditions also. Ocular examination of human is by ultrasound is very accurate for the disease conditions.
- Cardiac Evaluation– Ultrasonography of the heart is termed as echocardiography. With the help of the echocardiography a clinician can evaluate the different aspects of the heart. Echocardiography is the ultimate method of diagnosis of cardiac associated problems in humans as well as animals.
- Biopsy of organ/tissue- Biopsy of tissue for the diagnosis of the different kind of neoplasm also can be performed by the use of ultrasound.
- Aspiration of content in normal/abnormal– Ultrasound method is also used for the aspiration of normal and abnormal content for the general evaluation or diagnosis of the disease.
- Diagnosis of Myopathy – In cases of the muscles related studies ultrasound is used frequently. Myopathy is the condition in which the muscles are affected and there is abnormality in the muscles. Ultrasound becomes the accurate method of diagnosis for this type of the condition in patients.
- Diagnosis of Lesions in Fluid Filled Cavities– In different types of pathological conditions fluids accumulates in the body cavities or it accumulates in a specific area. For knowing the nature of the fluid which is accumulates in the body cavity or a particular area ultrasounds are used.
Pregnancy Diagnosis– Pregnancy diagnosis can be done by using the ultrasound. This is the very accurate method used in humans, cattle and dogs also. To regulate the use of ultrasound very strict laws pf the government are imposed because by using the ultrasound an exert can also know the sex of the child before birth. So many regulations are used to maintain the sex ratio in many countries.