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What is ultrasound? (how does it work?)
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How are images produced in ultrasound?
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ULTRASOUND
Lecture 4 -9/17
| Question | Answer |
|---|---|
| What is ultrasound? (how does it work?) | an imaging technique that uses high frequency sound waves to produce images or organs and structures in the body. |
| How are images produced in ultrasound? | by recording the reflections (echoes) of ultrasonic waves directed into the body. |
| Two functions of the transducer? | admits sound waves and reads them |
| High frequency transducer = what? | more superficial read. |
| Low frequency transducer = what? | will go deeper into the body |
| Why are some transducers flat? | to have constant contact with the body |
| Linear or curved linear traducers are used for? | abdomens |
| Sound waves that are heard by the human ear are called? What is their frequency? | Audible, 20-Hz-20kHz |
| Sound waves with higher frequencies than audible are called? What is their frequency? | Ultrasonic, 1-17MHz |
| Sound waves are transmittable only in ______ &_______, not in ______ or ______. | liquids & solids, air or gas |
| Why is ultrasound harmless? | Because there is no ionizing of the tissue |
| Ultrasound can be traced back to when? | WW1 |
| What is sonar? | a technique of sending out sound waves through the water and reading and observing the returning echoes to look for objects |
| What is A-mode ultrasound? | The first unit built in early 1950's by the Japanese. Anatomy was represented by a series of "blips" on the screen, height was related to the returning echo. |
| What is B-mode ultrasound? | Japan, US, and Europe developed 2-D gray scale system. Returning echoes represented by varying degrees of gray. |
| When was real time dynamic introduced? | During the 1970's with the introduction of computers |
| Who was the first to use doppler? and for what? | Japan, to evaluate vascular structures and blood flow. |
| When was doppler introduced? and for what? | In the 1980's, color used to evaluate vascular structures and blood flow, speed, and direction. |
| When were digital systems introduced? And what did it allow? | In the 1990's, convert to digital format, processing, manipulation, viewing, storage, and send images to remote sites. |
| What does the transducer do? | converts one energy to another. (electrical energy to ultasound energy) sends sound waves and reads them. |
| The transducer contains a ______ ___ that creates _____ frequency sound when an electrical current is passed through it causing it to ________. Which is called "_________ ____" | ceramic material, high, vibrate. Piezoelectric effect. |
| What does "Piezoelectric Effect" mean? | pressure electric |
| Piezoelectric effect describes... | the property of certain crystals expanding and contracting in response to the application of an electric field. |
| What does using gel do? | it ensures there is no loss of signal, as a result of trapped air between the transducer and the skin. |
| What is the frequency range of a high frequency transducer? And what type of exams would we use them for? | 5-7MHz, small abdomens, necks, vascular |
| What is the frequency range of a low frequency transducer? And what type of exams would we use them for? | 3.5MHZ average to larger abdomens |
| The reflected sound waves are called? | echoes |
| Name two barriers in the human body. | Bone & Air |
| Ultrasound is the gold standard for what exams? (6) | pregnancy, infertility, GYN, gallbladder, carotids, evaluating vascular diseases |
| What is a dermoid cyst? | cystic teratoma that contains developmentally mature skin complete with hair follicles and sweat glands. Almost always benign. |
Created by:
Aborys88