Introduction to Ultrasound
Start
Introduction to Ultrasound
Click on any of the links below to find out more!
What Can We Actually See?
How Does Ultrasound Work?
Learning Objectives
Test Your Knowledge
Knobology
Virtual US Machine[Coming Soon]
Designed/illustrated/created by Charlie James Ultrasound images courtesy of Russell Frood Reviewed by Amy Feather
Learning Objectives
What's the point?
This resource hes been designed to give you a quick introduction/reminder of some foundational elements in ultrasound. The content covered is by no means exhaustive, but will hopefully help you prepare for your practical ultrasound sessions. On having completed this resource, you'll hopefully be able to:
- Describe, in simple terms, how an ultrasound image is generated
- Define the terms: attenuation, absorption, penetration and resolution with regard to ultrasound
- Explain how the density of a tissue will affect its tone on an ultrasound scan
- Explain how the frequency of an ultrasound wave affects its penetration and resolution
- Describe the mechanism of some commonly encountered artefacts
- Relate the orientation of a probe to the image on screen
- Describe how depth, gain and focus can modify an ultrasound image
How Does Ultrasound Work?
Introduction
Absorption
Reflection
Frequency vs. Resolution
Artefacts
Created by Charlie James Ultrasound images courtesy of Russell Frood
How Does Ultrasound Work?
Let's get physics-al
Ultrasound waves are high-frequency vibrations that extend well beyond the upper range of human hearing. In ultrasonography, these waves are sent through the body to help us visualise tissues and organs in real time.
The waves are generated by a transducer (commonly referred to as a ‘probe’). Specifically, piezoelectric crystals inside the transducer convert electricity into mechanical vibration (this movement creates the sound waves). As these waves travel through the body, they interact with the bodies’ tissues in a number of ways, for example, by being absorbed or reflected.
Piezoelectric crystals vibrate rapidly to create ultrasound waves
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation.
Attenuation: As ultrasound waves travel through the body, they gradually lose energy.
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation. Z is calculated by multiplying the density of the tissue by the frequency of the ultrasound beam. So, if the density of a tissue increases, impedance increases (and US waves will travel a shorter distance).
Ultrasound waves are absorbed more quickly by higher density tissues (right).
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation. Z is calculated by multiplying the density of the tissue by the frequency of the ultrasound beam. So, if the density of a tissue increases, impedance increases (and US waves will travel a shorter distance).
Somewhat counterintuitively, increasing the frequency of the sound waves also increases impedance. This means that high frequency US waves can’t travel as far into the body as low frequency US waves.
High frequency waves (right) are absorbed more quickly than low frequency waves.
Reflection
The theory discussed so far assumes that our ultrasound waves are travelling through a homogeneous, consistent tissue. But, unless you’re scanning a jellyfish, you’re likely to find the body is composed of various tissues, each with different acoustic impedances.
When an ultrasound beam passes through two regions of differing impedance, something odd happens. At the boundary between the two media, some of the US waves are reflected back towards the probe, whilst the rest continue as a transmitted beam.
Outgoing waves (left) reach a boundary between different tissues. At this point, some waves are reflected back towards the probe (R). The rest continue as a transmitted beam (T).
Reflection
The theory discussed so far assumes that our ultrasound waves are travelling through a homogeneous, consistent tissue. But, unless you’re scanning a jellyfish, you’re likely to find the body is composed of various tissues, each with different acoustic impedances.
When an ultrasound beam passes through two regions of differing impedance, something odd happens. At the boundary between the two media, some of the US waves are reflected back towards the probe, whilst the rest continue as a transmitted beam.
The greater the change in acoustic impedance, the greater the strength of reflection. So, when passing between two similar tissues, the reflection will be relatively weak, and most waves will be transmitted. But if there’s a large change in acoustic impedance, more waves are reflected, and fewer will be transmitted.
Denser tissues, such as bone (right) provide a stronger reflection than tissues such as muscle (left).
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle.
The pulse-echo principle. Piezoelectric crystals generate a pulse of outgoing ultrasound waves (left), then pause to receive any reflected echoes (right)
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle.
Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues (left) appear on ultrasound (right).
Dark or hypo-echoic
Liquid
Bone
Muscle
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle.
Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues appear on ultrasound.
Bright or hyper-echoic
Liquid
Bone
Muscle
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle.
Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues appear on ultrasound.
Black or anechoic
Liquid
Bone
Muscle
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrate) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrates) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrates) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Artefacts
Ultrasound can be a great visualisation tool, but isn't perfect. As you scan, you may encounter artefacts - misinterpreted echoes that create a false visualisation of the body. Here are some of the major ones to look out for: Acoustic Shadowing When ultrasound waves meet a highly reflective structure (such as bone, or gallstones), the majority are reflected towards the probe, with only a few being transmitted more deeply. This creates a bright, hyperechoic region with an unusually dark, hypoechoic shadow extending beyond it.
Artefacts
Acoustic Enhancement/Flaring Conversely, the beam may travel through a region of low acoustic impedance (such as the gallbladder). In this case, the beams suffers little attenuation and remains unusually strong when it reaches underlying tissues. This results in the region beyond the tissue appearing significantly brighter than surrounding areas.
Artefacts
Acoustic Enhancement/Flaring Conversely, the beam may travel through a region of low acoustic impedance (such as the gallbladder). In this case, the beams suffers little attenuation and remains unusually strong when it reaches underlying tissues. This results in the region beyond the tissue appearing significantly brighter than surrounding areas.
What Are We Actually Seeing?
Viewing a trifle
Viewing the heart
Created by Charlie James Ultrasound images courtesy of Russell Frood
What Are We Actually Seeing?
The slice is right
One of the hardest parts of working with ultrasound can be relating what you see on screen to the anatomy of the human body. Essentially, an ultrasound scan shows a two-dimensional slice through a three-dimensional structure. This 'slice' passes from the end of the probe and through the body. What you see on screen is every structure that it meets, in the order that it meets them. The human body can be complex (and weridly shaped) so first, let's try scanning something simpler. The image on the right shows the World's Worst Trifle. A block of jelly sits atop a bed of custard and, deep inside the gelatinous mass, is a single, unpeeled banana. Each of the arrows [A, B, C D] represents a different orientation for placing an ultrasound probe. Try clicking through the arrows and see how it affects your view of the trifle.
In this orientation, we can see a transverse section that's similar to A. However, as the sponge is now perpendicular to the probe, it appears along one side of the image [N.B. the side it’s on will be determined by which way round the probe is placed].
In this orientation, we can see a transverse section through the banana. The top of the screen relates to the position of the probe, with deeper structures, appearing lower on the screen. So, after a layer of jelly, we’ll see the banana, and, at the bottom, the custard.
In this orientation, we can see a sagittal section through the banana. The ultrasound beam passes through the banana before the custard, so the banana appears higher on the screen.
In this orientation, we can see a coronal section through the banana. However, since the beam from the ultrasound probe doesn't travel through the custard, only the jelly and banana can be seen.
What Are We Actually Seeing?
Scanning the human body works in exactly the same way - it's just that the shapes are more complex (hopefully). A good knowledge of three-dimensional anatomy is really helpful when orientating an ultrasound scan. In particular, it's useful to know which structures will be closest/furthest away from the probe, and the direction that they run in. Click on the arrows to see how the orientation of the probe affects your view of the heart.
Right ventricle
Left ventricle
Right atrium
Left atrium
In this orientation, the slice cuts through all four chambers of the heart. The probe is closest to the apex, so that appears at the top of the scan, with the atria at the bottom. This is an apical four-chamber view.
Right ventricle
Papillary muscle
Left ventricle
In this orientation, the probe cuts transversely through the heart, taking a section through both ventricles, and the wall between them. Depending in the proximity to the apex, papillary muscles may also be seen. This is a parasternal short axis view.
Knobology
Introduction
Depth
Gain
Focus
Created by Charlie James Ultrasound images courtesy of Russell Frood
Knobology: An Introduction
Getting the perfect picture
'Knobology' is a term for adjusting the ultrasound setting to create the best possible image. Previously, this would have involved the manipulation of various buttons or knobs, whereas nowadays, many scanners use touch screens (but touch-screen-ology just doesn't have the same ring to it). There are plenty of options you can use to fine tune your image, but for now, let's focus on three of the most important ones... The image on the right shows an ultrasound scan of a kidney. Click on the buttons below the scan to explore how each variable can change the field of view.
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it.
Reduce depth
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it.
Increase depth
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Reduce gain
Increase gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Reduce gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Increase gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed. Focus Changing the focus allows you to concentrate ultrasound waves at a specific depth, maximising the resolution within that area [the depth of focus is marked by yellow arrows along the side of the screen].
Shallower focus
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed. Focus Changing the focus allows you to concentrate ultrasound waves at a specific depth, maximising the resolution within that area [the depth of focus is marked by yellow arrows along the side of the screen].
Deeper focus
Virtual Ultrasound Machine
Something something
Loris etc. Text to be added later
Test Your Knowledge!
Start
Congratulations - you've finished the quiz!
How many did you get correct?
1-3: Some reflection needed 4-6: Slight attenuation 7-9: Knowledge absorbed
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Transcript
Introduction to Ultrasound
Start
Introduction to Ultrasound
Click on any of the links below to find out more!
What Can We Actually See?
How Does Ultrasound Work?
Learning Objectives
Test Your Knowledge
Knobology
Virtual US Machine[Coming Soon]
Designed/illustrated/created by Charlie James Ultrasound images courtesy of Russell Frood Reviewed by Amy Feather
Learning Objectives
What's the point?
This resource hes been designed to give you a quick introduction/reminder of some foundational elements in ultrasound. The content covered is by no means exhaustive, but will hopefully help you prepare for your practical ultrasound sessions. On having completed this resource, you'll hopefully be able to:
How Does Ultrasound Work?
Introduction
Absorption
Reflection
Frequency vs. Resolution
Artefacts
Created by Charlie James Ultrasound images courtesy of Russell Frood
How Does Ultrasound Work?
Let's get physics-al
Ultrasound waves are high-frequency vibrations that extend well beyond the upper range of human hearing. In ultrasonography, these waves are sent through the body to help us visualise tissues and organs in real time. The waves are generated by a transducer (commonly referred to as a ‘probe’). Specifically, piezoelectric crystals inside the transducer convert electricity into mechanical vibration (this movement creates the sound waves). As these waves travel through the body, they interact with the bodies’ tissues in a number of ways, for example, by being absorbed or reflected.
Piezoelectric crystals vibrate rapidly to create ultrasound waves
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation.
Attenuation: As ultrasound waves travel through the body, they gradually lose energy.
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation. Z is calculated by multiplying the density of the tissue by the frequency of the ultrasound beam. So, if the density of a tissue increases, impedance increases (and US waves will travel a shorter distance).
Ultrasound waves are absorbed more quickly by higher density tissues (right).
Absorption
As ultrasound waves travel through the body, their energy is absorbed by the bodies’ tissues (this loss of energy is known as attenuation). Acoustic impedance (Z) is a term used to describe how much resistance an ultrasound wave experiences as it passes through a tissue. The higher the value of Z, the greater the resistance, and the faster the rate of attenuation. Z is calculated by multiplying the density of the tissue by the frequency of the ultrasound beam. So, if the density of a tissue increases, impedance increases (and US waves will travel a shorter distance). Somewhat counterintuitively, increasing the frequency of the sound waves also increases impedance. This means that high frequency US waves can’t travel as far into the body as low frequency US waves.
High frequency waves (right) are absorbed more quickly than low frequency waves.
Reflection
The theory discussed so far assumes that our ultrasound waves are travelling through a homogeneous, consistent tissue. But, unless you’re scanning a jellyfish, you’re likely to find the body is composed of various tissues, each with different acoustic impedances. When an ultrasound beam passes through two regions of differing impedance, something odd happens. At the boundary between the two media, some of the US waves are reflected back towards the probe, whilst the rest continue as a transmitted beam.
Outgoing waves (left) reach a boundary between different tissues. At this point, some waves are reflected back towards the probe (R). The rest continue as a transmitted beam (T).
Reflection
The theory discussed so far assumes that our ultrasound waves are travelling through a homogeneous, consistent tissue. But, unless you’re scanning a jellyfish, you’re likely to find the body is composed of various tissues, each with different acoustic impedances. When an ultrasound beam passes through two regions of differing impedance, something odd happens. At the boundary between the two media, some of the US waves are reflected back towards the probe, whilst the rest continue as a transmitted beam. The greater the change in acoustic impedance, the greater the strength of reflection. So, when passing between two similar tissues, the reflection will be relatively weak, and most waves will be transmitted. But if there’s a large change in acoustic impedance, more waves are reflected, and fewer will be transmitted.
Denser tissues, such as bone (right) provide a stronger reflection than tissues such as muscle (left).
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle.
The pulse-echo principle. Piezoelectric crystals generate a pulse of outgoing ultrasound waves (left), then pause to receive any reflected echoes (right)
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle. Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues (left) appear on ultrasound (right).
Dark or hypo-echoic
Liquid
Bone
Muscle
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle. Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues appear on ultrasound.
Bright or hyper-echoic
Liquid
Bone
Muscle
Reflection
The piezoelectric crystals that produced the US waves are also responsible for receiving these reflected signals. However, since they can’t send and receive sound waves at the same time, outgoing waves are produced in pulses, with a pause between them to receive any reflected ‘echoes’. This is the pulse-echo principle. Once received by the transducer, the reflected waves are used to build an image of what can be seen. Stronger reflections produce brighter tones and weaker reflections produce darker tones. Click the buttons below to see how different tissues appear on ultrasound.
Black or anechoic
Liquid
Bone
Muscle
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrate) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrates) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Frequency vs. Resolution
We’ve seen that the lower the frequency, the further a sound wave can travel (or penetrates) through the body. So, why not just use the lowest possible frequency for every scan? Well, you also need to consider the level of detail, or ‘resolution’ of the scan. Big, low frequency waves travel further through tissues, but are less likely to interact with fine structures – resulting in fewer reflections, and lower resolution. High frequency waves may not reach deeper tissues, but provider a higher resolution. Try adjusting the frequency of the probe (left) and seeing how it changes what's visible (right).
Artefacts
Ultrasound can be a great visualisation tool, but isn't perfect. As you scan, you may encounter artefacts - misinterpreted echoes that create a false visualisation of the body. Here are some of the major ones to look out for: Acoustic Shadowing When ultrasound waves meet a highly reflective structure (such as bone, or gallstones), the majority are reflected towards the probe, with only a few being transmitted more deeply. This creates a bright, hyperechoic region with an unusually dark, hypoechoic shadow extending beyond it.
Artefacts
Acoustic Enhancement/Flaring Conversely, the beam may travel through a region of low acoustic impedance (such as the gallbladder). In this case, the beams suffers little attenuation and remains unusually strong when it reaches underlying tissues. This results in the region beyond the tissue appearing significantly brighter than surrounding areas.
Artefacts
Acoustic Enhancement/Flaring Conversely, the beam may travel through a region of low acoustic impedance (such as the gallbladder). In this case, the beams suffers little attenuation and remains unusually strong when it reaches underlying tissues. This results in the region beyond the tissue appearing significantly brighter than surrounding areas.
What Are We Actually Seeing?
Viewing a trifle
Viewing the heart
Created by Charlie James Ultrasound images courtesy of Russell Frood
What Are We Actually Seeing?
The slice is right
One of the hardest parts of working with ultrasound can be relating what you see on screen to the anatomy of the human body. Essentially, an ultrasound scan shows a two-dimensional slice through a three-dimensional structure. This 'slice' passes from the end of the probe and through the body. What you see on screen is every structure that it meets, in the order that it meets them. The human body can be complex (and weridly shaped) so first, let's try scanning something simpler. The image on the right shows the World's Worst Trifle. A block of jelly sits atop a bed of custard and, deep inside the gelatinous mass, is a single, unpeeled banana. Each of the arrows [A, B, C D] represents a different orientation for placing an ultrasound probe. Try clicking through the arrows and see how it affects your view of the trifle.
In this orientation, we can see a transverse section that's similar to A. However, as the sponge is now perpendicular to the probe, it appears along one side of the image [N.B. the side it’s on will be determined by which way round the probe is placed].
In this orientation, we can see a transverse section through the banana. The top of the screen relates to the position of the probe, with deeper structures, appearing lower on the screen. So, after a layer of jelly, we’ll see the banana, and, at the bottom, the custard.
In this orientation, we can see a sagittal section through the banana. The ultrasound beam passes through the banana before the custard, so the banana appears higher on the screen.
In this orientation, we can see a coronal section through the banana. However, since the beam from the ultrasound probe doesn't travel through the custard, only the jelly and banana can be seen.
What Are We Actually Seeing?
Scanning the human body works in exactly the same way - it's just that the shapes are more complex (hopefully). A good knowledge of three-dimensional anatomy is really helpful when orientating an ultrasound scan. In particular, it's useful to know which structures will be closest/furthest away from the probe, and the direction that they run in. Click on the arrows to see how the orientation of the probe affects your view of the heart.
Right ventricle
Left ventricle
Right atrium
Left atrium
In this orientation, the slice cuts through all four chambers of the heart. The probe is closest to the apex, so that appears at the top of the scan, with the atria at the bottom. This is an apical four-chamber view.
Right ventricle
Papillary muscle
Left ventricle
In this orientation, the probe cuts transversely through the heart, taking a section through both ventricles, and the wall between them. Depending in the proximity to the apex, papillary muscles may also be seen. This is a parasternal short axis view.
Knobology
Introduction
Depth
Gain
Focus
Created by Charlie James Ultrasound images courtesy of Russell Frood
Knobology: An Introduction
Getting the perfect picture
'Knobology' is a term for adjusting the ultrasound setting to create the best possible image. Previously, this would have involved the manipulation of various buttons or knobs, whereas nowadays, many scanners use touch screens (but touch-screen-ology just doesn't have the same ring to it). There are plenty of options you can use to fine tune your image, but for now, let's focus on three of the most important ones... The image on the right shows an ultrasound scan of a kidney. Click on the buttons below the scan to explore how each variable can change the field of view.
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it.
Reduce depth
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it.
Increase depth
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Reduce gain
Increase gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Reduce gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed.
Increase gain
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed. Focus Changing the focus allows you to concentrate ultrasound waves at a specific depth, maximising the resolution within that area [the depth of focus is marked by yellow arrows along the side of the screen].
Shallower focus
Knobology: An Introduction
Getting the perfect picture
Depth In short, how far into the body do you need your ultrasound to scan? Ideally, this will be deep enough to see your structure of interest, but without an excessive field of view below it. Gain This setting adjusts the strength of the returning echoes, making the image brighter or darker as needed. Focus Changing the focus allows you to concentrate ultrasound waves at a specific depth, maximising the resolution within that area [the depth of focus is marked by yellow arrows along the side of the screen].
Deeper focus
Virtual Ultrasound Machine
Something something
Loris etc. Text to be added later
Test Your Knowledge!
Start
Congratulations - you've finished the quiz!
How many did you get correct?
1-3: Some reflection needed 4-6: Slight attenuation 7-9: Knowledge absorbed
Home