Ultrasound written test

Sine wave

A mathematical curve respresenting smooth repetitive oscillator.

Acoustic impededance.

How much resistance an ultrasound beam encounters as it passes through a tissue. It depends on the velocity of sound wave transmitted through the tissue median.

Homogenous

Parenchyma (tissue) of a structure exhibits uniform echotexture

Heterogenous

Structure with non similar components or elements, appearing irregular.

Hyper-echoic

Bright white section

Anechoic

Lack of echo, appears very dark and black.

TGC - time gain composition

Is used to adjust the image and acts as a post processing effect. Can be used to visual deeper antomy.

Pulse echo principle

Is the principle of the transducer emitting sound waves and reflecting off the structures within the body before then receiving the echo back to the transducer. Uses high frequency generator that generates short wave length

Ultrasound

Uses high-frequency sound waves to create real time pictures or video of internal organs or other soft tissues, such as blood vessels.

Brightness mode

linear array of transducers simultaneously scans a plane through body that can views as 2D image on screen

A-mode (amplitude mode)

Is most simplest mode. A single transducer scans a line through body with echos plotted on screen as function depth.

M-mode ( motion mode)

Rapid sequence of bmode scans where images follow each other in a sequence of screen . Able to see range of motion

Doppler mode.

Non invasive test used to measure the blood flow through blood vessels.

Colour doppler

this test uses a computer to change sound wave measurement into different colours. The colours show the speeed and direction of blood flow.

Power Doppler

Technique that uses the amplitude of Doppler signal to detect moving matter

Spectral Doppler

This test shows blood flow information in a graph. It can show how much of blood vessel is blocked. There’s 2 types. Pulsed wave: Doppler can show wher blood is flowing at different speeds. Continuous wave Doppler can record very fast blood flow.

Duplex Doppler

Test uses standard ultrasound to take images showing blood flow.

Piezoelectric effect

Converts kinetic or mechanical energy due to crystal deformation into electrical energy. This is how ultrasound transducers receive the sound waves.

Curve linear probe.

Known as trans abdominal or obstetrics scanning. Low frequency probe allows deeper scanning and structures are attenuated lesss. Low frequency probe. (2-5mHz)

Linear transducer

Produces a field of perpendicular to probe face. Mid range frequency. Commonly used for vascular, musculoskeletal, small parts. Smaller footprint than curve linear. (5-12MHz)z

Phased array transducer

An ultrasonic testing transducer that contains a series of elements that can be pulsed in unison to direct sound waves in a specific direction

Endo transducer

Provides you with the opportunity to perform internal examinations of the patient

High frequency

Travels less, high pitch, shorter wavelength

Low frequency

Deeper pitch, travels more distance. Longer wavelength

Spatial resolution

Ability to detect and display structures that are close together.

Temporal resolution

Anatomical structures are displayed on the screen of the ultrasound machine. In 2 or 3 dimensions as sequential frames over time

Contrast resolution

Ability to identify differences between adjacent soft tissue regions

Amplitude

Height or strength of wave length defined by the distance between the peak and the average of the waves highest and lowest points

Reverberation

Echos become trapped between multiple reflective surfaces thi can cause echoes to be places deeper in image

Mirroring

Large reflective surface can cause an area to be imaged twice one by the original beam and then again by echo

Acoustic shadowing

An echo poor or anechoic area is created behind a strong reflective surface such as stones, bone and gas

Target contrast enhanced

Contrast agent bind to specific tissue types. When organ scanned the contrast bubbles increase the amount of strong reflections from that area enhancing the image